[From the U.S. Government Printing Office, www.gpo.gov]



                                                                                                                                                                                                                            A
                                                                                                                                                                                                          OCS ElS/r:A
                                                                                                                                                                                                          MMS 92-"7
                      Gulf of Mexico
                      Sales 142 and 143:

                      Central and Western Planning Areas

                      Draft Environmental Impact Statement

                      Volume 1: Sections I through IV.C.





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                                                     U.S. Department of the Interior
                                                     Minerals Management Service
                                                     Gulf of Mexico OCS Region















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                                                                                             OCS ElS/r:A
                                                                                             MMS 92-"7
             Gulf of Mexico
             Sales 142 and 143:


             Central and Western Planning Areas

             Draft Environmental Impact Statement


             Volume 1: Sections I through IV.C.







             Author


             Minerals Management Service
             Gulf of Mexico OCS Region




                                                             U - S . DEPARTMENT OF COMMERCE NOAA
                                                             COASTAL SERVICES CENTER
                                                             2234 SOUTH HOBSON AVENUE
                                                             CHARLESTON    SC 29405-2413







                                                               Property of         Library





         CID




             Published by

             U.S. Department of the Interior
             Minerals Management Service                                                New Orleans
             Gulf of Mexico OCS Region                                                  April 1992

























                                               REGIONAL DIRECTOR'S NOTE






                                  This Draft Environmental Impact Statement (EIS) covering the proposed
                              OCS off and gas lease sales in the Gulf of Mexico for 1993 is a product of
                              the Minerals Management Service (MMS) in New Orleans, Louisiana. The
                              proposed sales are Central Gulf of Mexico Sale 142 (March 1993) and
                              Western Gulf of Mexico Sale 143 (August 1993). This document includes
                              the purpose and background of the proposed actions, the alternatives, the
                              description of the affected environment, and the potential environmental
                              impacts of the proposed actions and alternatives. Mitigating measures and
                              their effects and potential cumulative impacts are also discussed. Most of
                              the visuals that are referred to in this document were distributed with the
                              Draft EIS for Sales 131, 135, and 137. Visual No. 2, Areas of Multiple Use,
                              was revised and was distributed with the Draft EIS for Sales 139 and 141.
                                  Additional copies of this Draft EIS and the referenced visuals may be
                              obtained from the MMS, Gulf of Mexico OCS Region, 1201 Elmwood Park
                              Boulevard, New Orleans, Louisiana 70123-2394, Attention: MS 5034, or by
                              telephone (504) 736-2519.
                                  Comments on this Draft EIS should be sent to the same address,
                              Attention: MS 5410.
                                                             Al. R o TPe- a 4rc,
                                                                    Regional Director
                                                                    Minerals Management Service
                                                                    Gulf of Mexico OCS Region













                                                                                                               v







                                                    COVER SHEET

                                 Environmental Impact Statement for Proposed Central Gulf of
                                    Mexico OCS Lease Sale 142 (March 1993) and Proposed
                                   Western Gulf of Mexico OCS Lease Sale 143 (August 1993)

                    Draft (x)                              Final

             Type of Action:

                    Administrative (x)             Legislative

             Area of Potential Impact:

                    Offshore Marine Environment and Coastal Counties/Parishes of Alabama, Mississippi, Louisiana, and
                    Texas


             Lead Agency:

                    Send Comments To:


                    U.S. Department of the Interior
                    Minerals Management Service
                    Gulf of Mexico OCS Region
                    1201 Elmwood Park Boulevard
                    New Orleans, LA 70123-2394
                    Attention: MS 5410


             Region Contact:

                    Dennis L. Chew
                    (504) 736-2793 or (FTS) 686-2793

             Washington Contact:

                    Richard H. Miller
                    U.S. Department of the Interior
                    Minerals Management Service
                    381 Elden Street (MS 4320)
                    Herndon, VA 22070-4817
                    (703) 787-1665 or (FTS) 393-1665











                 TABLE OF CONTENTS



                 FIGURES                                                                                                              xxi


                 TABLES                                                                                                               xxiii


                 ABBREVIATIONS AND ACRONYMS                                                                                           xxv


                 SUMMARY                                                                                                              Xxix


                                                                      VOLUMEI


                 1.       THE PROPOSED ACTIONS                                                                                        1-3


                          A.        PURPOSE, NEED, AND DESCRIPTION                                                                    1-3


                          B.        BACKGROUND                                                                                        1-7


                                    1.       Administrative Events Leading to the Proposed Actions                                    1-7

                                    2.       Scoping Activities and Findings                                                          1-8
                                             a.        Alternatives                                                                   1-8
                                                       (1)     Alternatives for Proposed Central Gulf Sale 142                        1-8
                                                       (2)     Alternatives for Proposed Western Gulf Sale 143                        1-8
                                                       (3)     Alternatives Considered But Not Offered                                1-8
                                             b.        Mitigating Measures                                                            1-9
                                                       (1)     Potential Mitigating Measures Analyzed in the EIS                      1-9
                                                       (2)     Mitigating Measures Considered But Not Analyzed                        1-10
                                             C.        Issues                                                                         I-11
                                                       (1)     Significant Issues                                                     1-11
                                                       (2)     Issues Considered But Not Analyzed                                     1-12

                                    3.       Regulatory and Administrative Framework                                                  1-12
                                             a.        Outer Continental Shelf Lands Act                                              1-12
                                             b.        National Environmental Policy Act                                              1-13
                                             C.        Presale Activities                                                             1-14
                                                       (1)     Federal/State Coordination                                             1-14
                                                       (2)     Geological and Geophysical Exploration
                                                               Regulations/Coordination                                               1-15
                                             d.        Postsale Activities                                                            1-16
                                                       (1)     Review, Coordination, and Approval of
                                                               Exploration, Development, and Production
                                                               Activities                                                             1-16
                                                               (a)      Exploration Plans                                             1-16
                                                               (b)       DeNelopment and Production Plans                             1-17
                                                               (c)       Oil Spill Contingency Plans                                  1-18
                                                               (d)       Hydrogen Sulfide Contingency Plans                           1-18











                    viii


                                                                     (e)       Environmental Information                                      1-18
                                                                     (f)       Air Emissions Information                                      1-19
                                                                     (g)       Site Clearance                                                 1-20
                                                                     (h)       Coastal Zone Management Consistency Review
                                                                               and Appeals for Plans                                          1-20
                                                           (2)       Enforcement Measures                                                     1-21
                                                                     (a)       Inspections                                                    1-21
                                                                     (b)       Suspension of Operations                                       1-22
                                                                     (c)       Cancellation of Leases                                         1-22
                                                                     (d)       Remedies and Penalties                                         1-23
                                                           (3)       Environmental Safeguards                                                 1-23
                                                                     (a)       OCS Regulations                                                1-23
                                                                     (b)       OCS Structures and Equipment                                   1-24
                                                                     (c)       Lease Stipulations                                             1-26
                                                                     (d)       Other MMS Environmental Safety Controls                        1-26
                                                                     (e)       Prevention and Control Regulations for
                                                                               Spills and Discharges                                          1-27
                                                                     (f)       Federal Compensation for Damages or Pollution                  1-32

                                       4.        Interrelationship with Other Federal Policies Governing OCS
                                                 Environmental Resources                                                                      1-34
                                                 a.        Ports and Waterways Safety Act                                                     1-34
                                                 b.        Archaeological Resources Legislation                                               1-35
                                                 C.        Endangered Species Act of 1973                                                     1-35
                                                 d.        Marine Mammal Protection Act of 1972                                               1-35
                                                 e.        Magnuson Fishery Conservation and Management
                                                           Act of 1976                                                                        1-37
                                                 f.        National Fishing Enhancement Act of 1984                                           1-37
                                                 9-        Executive Order 11990 (May 24, 1977), Protection of
                                                           Wetlands                                                                           1-37
                                                 h.        Marine and Estuarine Sanctuaries Legislation                                       1-38
                                                 i.        Ocean Dumping                                                                      1-42
                                                 j.        Rivers and Harbors Act of 1899                                                     142
                                                 k.        Coastal Barrier Resources Act of 1982                                              142
                                                 1.        National Ocean Pollution Planning Act of 1978                                      1-42
                                                 In.       Coastal Zone Management Act of 1972                                                142

                                       5.        Gulf of Mexico Regional Environmental Studies Program                                        144

                   Il.       ALTERNATIVES INCLUDING THE PROPOSED ACTIONS                                                                      11-3


                             A@        PROPOSED CENTRAL GULF SALE 142                                                                         11-3


                                       1.        Alternative A - The Proposed Action                                                          11-3
                                                 a.        Description                                                                        11-3
                                                 b.        Summary of Impacts                                                                 11-5
                                                 C.        Mitigating Measures                                                               11-14
                                                           (1)       Topographic Features Stipulation                                        11-14
                                                           (2)       Live Bottom (Pinnacle Trend) Stipulation                                11-17
                                                           (3)       Archaeological Resource Stipulation                                     11-18
                                                           (4)       Military Areas Stipulation                                              11-20
                                                           (5)       Notices to Lessees and Letters to Lessees                               11-22












                                                                                                                                                 ix

                                      2.       Alternative B - The Proposed Action Excluding the Blocks
                                               Near Biologically Sensitive Topographic Features                                              11-23
                                               a.        Description                                                                         11-23
                                               b.        Summary of Impacts,                                                                 11-28

                                      3.       Alternative C - No Action                                                                     11-30
                                               a.        Description                                                                         11-30
                                               b.        Summary of Impacts                                                                  11-30

                                      4.       Comparison of Alternatives                                                                    11-31

                            B.        PROPOSED WESTERN GULF SALE 143                                                                         11-31

                                      1.       Alternative A - The Proposed Action                                                           11-31
                                               a.        Description                                                                         11-31
                                               b.        Summary of Impacts                                                                  11-33
                                               C.        Mitigating Measures                                                                 11-41
                                                         (1)       Topographic Features Stipulation                                          11-41
                                                         (2)       Archaeological Resource Stipulation                                       11-45
                                                         (3)       Military Areas Stipulation                                                11-47
                                                         (4)       Notices to Lessees and Letters to Lessees                                 11-48

                                      2.       Alternative B - The Proposed Action Excluding the Blocks
                                               Near Biologically Sensitive Topographic Features                                              11-48
                                               a.        Description                                                                         11-48
                                               b.        Summary of Impacts                                                                  11-53

                                      3.       Alternative C - The Proposed Action Excluding the Western
                                               Naval Operations Area                                                                         11-55
                                               a.        Description                                                                         11-55
                                               b.        Summary of Impacts                                                                  11-56

                                      4.       Alternative D - No Action                                                                     11-58
                                               a.        Description                                                                         11-58
                                               b.        Summary of Impacts                                                                  11-58

                                      5.       Comparison of Alternatives                                                                    11-59

                           DESCRIPTION OF THE AFFECTED ENVIRONMENT                                                                           111-3

                           A-         PHYSICAL ELEMENTS OF THE ENVIRONMENT                                                                   111-3

                                      1.       Geology                                                                                       111-3

                                      2.       Meteorological Conditions                                                                     111-5

                                      3.       Air Quality                                                                                  111-10

                                      4.       Physical Oceanography                                                                        111-14

                                      5.       Chemical Oceanography                                                                        111-18













                   x

                                      6.       Water Quality                                                                          111-24
                                               a.       Offshore                                                                      111-24
                                               b.       Coastal and Nearshore                                                         111-25

                            B.        BIOLOGICAL RESOURCES                                                                            111-28

                                      1.       Sensitive Coastal Environments                                                         111-28
                                               a.       Barrier Beaches                                                               111-28
                                               b.       Wetlands                                                                      111-31


                                      2.       Sensitive Offshore Resources                                                           111-34
                                               a.       Live Bottoms (Pinnacle Trend)                                                 111-37
                                               b.       Deep-water Benthic Communities                                                111-39
                                               C.       Topographic Features                                                          111-41

                                      3.       Terrestrial and Marine Mammals                                                         111-49
                                               a.       Marine Mammals                                                                111-49
                                                        (1)       Nonendangered and Nonthreatened Species                             111-49
                                                        (2)       Endangered and Threatened Species                                   111-52
                                               b.       Alabama, Choctawhatchee, and Perdido Key Beach Mice                           111-52

                                      4.       Marine Turtles                                                                         111-53


                                      5.       Coastal and Marine Birds                                                               111-54
                                               a.       Nonendangered and Nonthreatened Species                                       111-54
                                               b.       Endangered and Threatened Species                                             111-55

                                      6.       Fish Resources                                                                         111-56
                                               a.       Nonendangered and Nonthreatened Species                                       111-56
                                               b.       Gulf Sturgeon                                                                 111-60

                            C.        OTHER RELEVANT ACTIVITIES AND RESOURCES                                                         111-60


                                      1.       OCS Oil and Gas Industry                                                               111-60

                                      2.       Socioeconomic Conditions                                                               111-64
                                               a.       Population, Labor, and Employment                                             111-64
                                               b        Public Services and Infrastructure                                            111-73
                                               C.       Social Patterns                                                               111-76


                                      3.       Commercial Fisheries                                                                   111-77


                                      4.       Recreational Resources and Activities                                                  111-80


                                      5.       Archaeological Resources                                                               111-83
                                               a.       Historic                                                                      111-83
                                               b.       Prehistoric                                                                   111-83

                                      6.       Coastal Zone Management Plans                                                          111-85











                                                                                                                               xi

               IV.     ENVIRONMENTAL CONSEQUENCES                                                                          IV-3

                       A. PROPOSED ACTION SCENARIO                                                                         IV-3


                                1.       Resource Estimates, Timetables, and Subarea. Descriptions                         IV-3

                                2.       Description of Offshore Operations and Impacting Factors                          IV-9
                                         a.       Offshore Infrastructure Activities                                       IV-9
                                                  (1)      Surveying/Seismic Operations                                    IV-9
                                                  (2)      Drilling Rigs and Platforms                                    IV-10
                                                           (a) Exploration and Delineation Phase                          IV-10
                                                           (b) Development Phase                                          IV-11
                                                           (c) Production Phase                                           IV-11
                                                  (3)      Structure Removals                                             IV-12
                                                           Workover/Abandonment Activities
                                                  (4)      Deep-water Activities                                          IV-13
                                         b.       Offshore Transport of Oil and Gas                                       IV-15
                                                  (1)      Pipelines                                                      IV-15
                                                  (2)      Oil Barges                                                     IV-20
                                                  (3)      Shuttle Tankers                                                IV-21
                                         C.       Offshore Transport of Personnel/Supplies                                IV-22
                                                  (1)      Service Vessels                                                IV-22
                                                  (2)      Helicopters                                                    IV-23
                                         d.       Offshore Impacting Factors Related to the
                                                  Proposed Actions                                                        IV-23
                                                  (1)      Bottom Disturbances                                            IV-23
                                                           (a)      Fixed Structures                                      IV-24
                                                           (b)      Anchoring                                             IV-24
                                                  (2)      Bottom Debris                                                  IV-25
                                                  (3)      Space-Use Conflicts                                            IV-26
                                                  (4)      Aesthetic Interference                                         IV-26
                                                  (5)      Offshore Operational Wastes                                    IV-26
                                                           (a)      Drilling Muds and Cuttings                            IV-29
                                                           (b)      Produced Waters                                       IV-30
                                                           (c)      Other Development/
                                                                    Production Fluids                                     IV-31
                                                           (d)      Production Sands/Solids/Equipment                     IV-32
                                                           (e)      Treated Domestic and Sanitary Wastes                  IV-33
                                                           (f)      Other Trash and Debris                                IV-33
                                                  (6)      Air Emissions                                                  IV-34
                                                  (7)      Noise                                                          IV-35
                                                  (8)      Blowouts                                                       IV-36
                                                  (9)      Offshore Spills                                                IV-37

                                 3.      Description of Onshore/Coastal Operations and Impacting Factors                  IV-37
                                         a.       Onshore Infrastructure                                                  IV-38
                                                  (1)      Scrvicc and Construction Facilities                            IV-38
                                                           (a)      Service Bases                                         IV-38
                                                           (b)      Heliports                                             IV-39
                                                           (c)      Pipeyafds                                             IV-39
                                                           (d)      Fabrication Yards                                     IV-39










                 xii

                                                    (2)      Processing and Storage Facilities                               IV-40
                                                             (a)      Oil Refineries                                         IV-40
                                                             (b)      Gas Processing Plants                                  IV-41
                                                             (c)      Separation Facilities                                  IV-41
                                                             (d)      Terminals                                              IV-42
                                           b.       Landings and Coastal Transport Operations                                IV-43
                                                    (1)      Pipelines                                                       IV-43
                                                    (2)      Oil Barges                                                      IV-43
                                                    (3)      Shuttle Tankers                                                 IV-44
                                                    (4)      Navigation Channels                                             IV-44
                                           C.       Onshore/Coastal Impacting Factors Related to the Proposed
                                                    Actions                                                                  IV-44
                                                    (1)      Disturbances from Use of Existing Infrastructure                IV-44
                                                             (a)      Nonpoint Source Discharges                             IV-45
                                                             (b)      Operational Discharges                                 IV-45
                                                             (c)    - Air Emissions                                          IV-46
                                                    (2)      Disturbances from New Infrastructure Emplacement                IV-46
                                                    (3)      Vessel Usage of Navigation Channels                             IV-46
                                                             (a)      Channel Back Erosion                                   IV-46
                                                             (b)      Vessel Operational Discharges                          IV-47
                                                             (c)      Maintenance/New Dredging                               IV-47
                                                    (4)      Onshore/Coastal Disposal of Offshore Oil and Gas
                                                             Industry Operational Wastes                                     IV-48
                                                             (a)      Produced Waters                                        IV-50
                                                             (b)      Production and Drilling Solids                         IV-51
                                                             (c)      Other Solid Wastes                                     IV-51
                                                    (5)      Onshore/Coastal Spills                                          IV-52

                         B.        CUMULATIVE SCENARIO                                                                       IV-52


                                  1.       EXPLORATION, DEVELOPMENT, AND PRODUCTION SCENARIO
                                           AND ASSUMPTIONS FOR THE OCS LEASING PROGRAM                                       IV-52


                                           a.       Resource Estimates and Timetables                                        IV-52
                                           b.       Description of Offshore Operations and Impacting Factors,                IV-53
                                                    (1)      Offshore Infrastructure and Activities                          IV-53
                                                             (a)      Surveying/Seismic Operations                           IV-53
                                                             (b)      Drilling Rigs and Platforms                            IV-53
                                                             (c)      Structure Removals                                     IV-57
                                                             (d)      Workover/Abandonment Activities                        IV-57
                                                    (2)      Offshore Transport of Off and Gas                               IV-58
                                                    (3)      Offshore Transport of Personnel/Supplies                        IV-60
                                                    (4)      Offshore Impacting Factors Related to Future
                                                             OCS Operations                                                  IV-61
                                                             (a)      Bottom Disturbances                                    IV-61
                                                             (b)      Bottom Debris                                          IV-62
                                                             (c)      Space-Use Conflicts                                    IV-62
                                                             (d)      Aesthetic Interference                                 IV-63
                                                             (e)      Offshore Operational Wastes                            IV-63
                                                             (f)      Air Emissions                                          IV-66
                                                             (g)      Noise                                                  IV-66
                                                             (h)      Blowouts                                               IV-66
                                                             (i)      Offshore Spills                                        IV-67











                                                                                                                                   xiii

                                           C.       Description of Onshore/Coastal Operations and Impacting Factors            IV-67
                                                    (1)      Onshore Infrastructure and Activities                             IV-67
                                                             (a)      Service and Construction Facilities                      IV-67
                                                             (b)      Processing and Storage Facilities                        IV-72
                                                    (2)      Landings and Coastal Transport Operations                         IV-73
                                                    (3)      Onshore/Coastal Impacting Factors Related to
                                                             OCS Activities                                                    IV-75
                                                             (a)      Disturbances from the Use of the Existing and New
                                                                      Infrastructure                                           IV-75
                                                             (b)      Vessel Usage of Navigation Channels                      IV-78
                                                             (c)      Onshore/Coastal Disposal of Offshore Wastes              IV-78
                                                             (d)      Onshore/Coastal Spills                                   IV-81

                                  2.       State Oil and Gas Activities                                                        IV-82
                                           a.       Leasing, Production, and Associated Infrastructure                         IV-82
                                           b.       Related Concerns                                                           IV-82
                                                    (1)      Drilling-Related Wastes                                           IV-82
                                                    (2)      Production-Related Wastes                                         IV-83

                                  3.       Other Major Offshore Activities                                                     IV-85
                                           a.       Ocean Dumping                                                              IV-85
                                           b.       Deep-water Ports                                                           IV-86
                                           C.       Non-energy Minerals Program in the Gulf of Mexico                          IV-86
                                           d.       Marine Transportation                                                      IV-87
                                           e.       Military Activities                                                        IV-88

                                  4.       Other Major Onshore/Coastal Activities                                              IV-89
                                           a.       River Development and Flood Control Projects                               IV,89
                                           b.       Submergence and Natural Subsidence of Wetlands                             IV-90
                                           C.       Contributors to Coastal Water Quality Problems                             IV-90

                                  5.       Activities Outside the Planning Areas Affecting Migratory Species                   IV-91
                                           a.       Coastal and Marine Birds                                                   IV-91
                                           b.       Marine Turtles                                                             IV-92
                                           C.       Cetaceans                                                                  IV-93
                                           d.       Fish Resources                                                             IV-93


                                  6.       Major Sources of Oil Contamination in the Gulf of Mexico                            IV-94
                                           a.       Other Sources of Oil Spills                                                IV-94
                                           b.       Operational Discharges                                                     IV-98
                                           C.       Other                                                                      IV-98


                         C.       OIL SPILLS OCCURRING IN CONNECTION WITH OCS OPERATIONS                                       IV-99


                                  1.       Historical Spill Occurrence and Assumptions                                        IV-100

                                  2.       Characteristics, Fates, and Effects                                                IV-106

                                  3.       Results of Oil Spill Risk Analysis                                                 IV-112

                                  4.       Oil Spill Prevention                                                               IV-127











                   xiv

                                     5.         Oil Spill Contingency Planning and Response                                        IV-130
                                                a.      Responsibility and Authority                                               IV-130
                                                b.      OR Spill Contingency Planning                                              IV-130
                                                C.      Spill Response Training/Drills                                             IV-133
                                                d.      Equipment Response and Capability                                          IV-134
                                                        (1)      Equipment Locations                                               IV-134
                                                        (2)      Equipment/Response Options and Effectiveness                      IV-138
                                                                 (a)      Mechanical Equipment                                     IV-138
                                                                 (b)      Chemicals/Dispersants Usage                              IV-140
                                                        (3)      Response Times                                                    IV-143
                                                        (4)      Offshore Cleanup Capability for Handling Various
                                                                 Size Spills                                                       IV-144
                                                        (5)      Coastal Cleanup Techniques and Effects                            IV-145
                                                        (6)      In Situ Burning                                                   IV-150
                                                        (7)      Bioremediation                                                    IV-151
                                                e.      Response Options for Handling Oiled Wildlife and Birds                     IV-152
                                                L       Recent Developments in Spill-Response Planning/Capabilities                IV-153

                                                                       VOLUME 11


                           D.       ENVIRONMENTAL IMPACTS OF THE PROPOSED ACTIONS AND
                                     ALTERNATIVES                                                                                  IV-159

                                    1.          PROPOSED CENTRAL GULF SALE 142                                                     IV-159
                                                a.      Alternative A - The Proposed Action                                        IV-159
                                                        (1)      Impacts on Sensitive Coastal Environments                         IV-159
                                                                 (a)      Coastal Barrier Beaches                                  IV-159
                                                                 (b)      Wetlands                                                 IV-164
                                                        (2)      Impacts on Sensitive Offshore Resources                           IV-171
                                                                 (a)      Live Bottoms (Pinnacle Trend)                            IV-171
                                                                 (b)      Deep-water Benthic Communities                           IV-175
                                                                 (c)      Topographic Features                                     IV-178
                                                        (3)      Impacts on Water Quality                                          IV-185
                                                        (4)      Impacts on Air Quality                                            IV-197
                                                        (5)      Impacts on Coastal and Marine Mammals                             IV-207
                                                                 (a)      Marine Mammals                                           IV-207
                                                                 (b)      Alabama, Choctawhatchee, and Perdido K ey
                                                                          Beach Mice                                               IV-215
                                                        (6)      Impacts on Marine Turtles                                         IV-217
                                                        (7)      Impacts on Coastal and Marine Birds                               IV-222
                                                                 (a)      Nonendangered and Nonthreatened Species                  IV-223
                                                                 (b)      Endangered and Threatened Species                        IV-227
                                                        (8)      Impacts on the Gulf Sturgeon                                      IV-230
                                                        (9)      Impacts on Commercial Fisheries                                   IV-232
                                                        (10)     Impacts on Recreational Resources and Activities                  IV-237
                                                                 (a)      Beach Use                                                IV-237
                                                                 (b)      Marine Fishing                                           IV-240
                                                        (11)     Impacts on Archaeological Resources                               IV-243
                                                                 (a)      Historic                                                 IV-244
                                                                 (b)      Prehistoric                                              IV-248













                                                                                                                              xv

                                                  (12)     Impacts on Socioeconomic Conditions                           IV-252
                                                           (a)     Population, Labor, and Employment                     N-252
                                                           (b)     Public Services and Infrastructure                    IV-262
                                                           (c)     Social Patterns                                       IV-266

                                         b.       Alternative B - The Proposed Action Excluding the Blocks
                                                  Near Biologically Sensitive Topographic Features                       IV-270
                                                  (1)      Impacts on Sensitive Coastal Environments                     IV-271
                                                           (a)     Coastal Barrier Beaches                               IV-271
                                                           (b)     Wetlands                                              IV-271
                                                  (2)      Impacts on Sensitive Offshore Resources                       IV-272
                                                           (a)     Live Bottoms (Pinnacle Trend)                         IV-272
                                                           (b)     Deep-water Benthic Communities                        IV-273
                                                           (c)     Topographic Features                                  IV-274
                                                  (3)      Impacts on Water Quality                                      IV-275
                                                  (4)      Impacts on Air Quality                                        IV-276
                                                  (5)      Impacts on Coastal and Marine Mammals                         IV-277
                                                           (a)     Marine Mammals                                        IV-277
                                                           (b)     Alabama, Choctawhatchee, and Perdido Key
                                                                   Beach Mice                                            IV-278
                                                  (6)      Impacts on Marine Turtles                                     IV-278
                                                  (7)      Impacts on Coastal and Marine Birds                           IV-278
                                                           (a)     Nonendangered and Nonthreatened Species               IV-278
                                                           (b)     Endangered and Threatened Species                     IV-279
                                                  (8)      Impacts on the Gulf Sturgeon                                  IV-279
                                                  (9)      Impacts on Commercial Fisheries                               IV-280
                                                  (10)     Impacts on Recreational Resources and Activities              IV-280
                                                           (a)     Beach Use                                             IV-280
                                                           (b)     Marine Fishing                                        IV-280
                                                  (11)     Impacts on Archaeological Resources                           IV-281
                                                           (a)     Historic                                              IV-281
                                                           (b)     Prehistoric                                           IV-282
                                                  (12)     Impacts on Socioeconomic Conditions                           IV-282
                                                           (a)     Population, Labor, and Employment                     IV-282
                                                           (b)     Public Services and Infrastructure                    IV-283
                                                           (c)     Social Patterns                                       IV-283
                                         C.       Impacts from Alternative C - No Action                                 IV-283
                                         d.       Impacts of Cumulative Actions                                          IV-284
                                                  (1)      Impacts on Sensitive Coastal Environments                     IV-284
                                                           (a)     Coastal Barrier Beaches                               IV-284
                                                           (b)     Wetlands                                              IV-288
                                                  (2)      Impacts on Sensitive Offshore Resources                       IV-294
                                                           (a)     Live Bottoms (Pinnacle Trend)                         IV-294
                                                           (b)     Deep-water Benthic Communities                        IV-297
                                                           (c)     Topographic Features                                  IV-298
                                                  (3)      Impacts on Water Quality                                      IV-301
                                                  (4)      Impacts on Air Quality                                        IV-309
                                                  (5)      Impacts on Coastal and Marine Mammals                         IV-314
                                                           (a)     Marine Mammals                                        IV-314
                                                           (b)     Alabama, Choctawhatchee, and Perdido Key
                                                                   Beach Mice                                            IV-319
                                                  (6)      Impacts on Marine Turtles                                     IV-320









                  X.Vi

                                                    (7)      Impacts on Coastal and Marine Birds                           IV-324
                                                             (a)      Nonendangered and Nonthreatened Species              TV-324
                                                             (b)      Endangered and Threatened Species                    IV-326
                                                    (8)      Impacts on the Gulf Sturgeon                                  IV-328
                                                    (9)      Impacts on Commercial Fisheries                               IV-330
                                                    (10)     Impacts on Recreational Resources and Activities              IV-332
                                                             (a)      Beach Use                                            IV-332
                                                             (b)      Marine Fishing                                       IV-334
                                                    (11)     Impacts on Archaeological Resources                           IV-335
                                                             (a)      Historic                                             IV-336
                                                             (b)      Prehistoric                                          IV-338
                                                    (12)     Impacts on Socioeconomic Conditions                           IV-340
                                                             (a)      Population, Labor, and Employment                    IV-340
                                                             (b)      Public Services and Infrastructure                   IV-346
                                                             (c)      Social Patterns                                      IV-348
                                           e.       Coastal. Zone Management Plans and Land Use                            IV-352

                                   2.      PROPOSED WESTERN GULF SALE 143                                                  IV-374
                                           a.       Alternative A - The Proposed Action                                    IV-374
                                                    (1)      Impacts on Sensitive Coastal Environments                     IV-375
                                                             (a)      Coastal Barrier Beaches                              IV-375
                                                             (b)      Wetlands                                             IV-378
                                                    (2)      Impacts on Sensitive Offshore Resources                       IV-384
                                                             (a)      Deep-water Benthic Communities                       IV-384
                                                             (b)      Topographic Features                                 IV-386
                                                    (3)      Impacts on Water Quality                                      IV-389
                                                    (4)      Impacts on Air Quality                                        IV-400
                                                    (5)      Impacts on Marine Mammals                                     IV-409
                                                             (a)      Nonendangered and Nonthreatened Species              IV-409
                                                             (b)      Endangered and Threatened Species                    IV-414
                                                    (6)      Impacts on Marine Turtles                                     IV-417
                                                    (7)      Impacts on Coastal and Marine Birds                           IV-422
                                                             (a)      Nonendangered and Nonthreatened Species              IV422
                                                             (b)      Endangered and Threatened Species                    IV426
                                                    (8)      Impacts on Commercial Fisheries                               IV429
                                                    (9)      Impacts on Recreational Resources and Activities              IV433
                                                             (a)      Beach Use                                            IV433
                                                             (b)      Marine Fishing                                       IV435
                                                    (10)     Impacts on Archaeological Resources                           IV-436
                                                             (a)      Historic                                             IV437
                                                             (b)      Prehistoric                                          IV-441
                                                    (11)     Impacts on Socioeconomic Conditions                           IV-444
                                                             (a)      Population, Labor, and Employment                    IV444
                                                             (b)      Public Services and Infrastructure                   IV454
                                                             (c)      Social Patterns                                      IV458
                                           b.       Alternative B - The Proposed Action Excluding the Blocks
                                                    Near Biologically Sensitive Topographic Features                       IV-463
                                                    (1)      Impacts on Sensitive Coastal Environments                     IV-464
                                                             (a)      Coastal Barrier Beaches                              IV-464
                                                             (b)      Wetlands                                             IV-464
                                                    (2)      Impacts on Sensitive Offshore Resources                       IV-465
                                                             (a)      Deep-water Benthic Communities                       IV-465
                                                             (b)      Topographic Features                                 IV-465











                                                                                                                              xvii

                                                  (3)      Impacts on Water Quality                                      IV-466
                                                  (4)      Impacts on Air Quality                                        IV-467
                                                  (5)      Impacts on Marine Mammals                                     IV-469
                                                           (a)     Nonendangered and Nonthreatened Species               IV-469
                                                           (b)     Endangered and Threatened Species                     IV-469
                                                  (6)      Impacts on Marine Turtles                                     IV-470
                                                  (7)      Impacts on Coastal and Marine Birds                           IV-470
                                                           (a)     Nonendangered and Nonthreatened Species               IV470
                                                           (b)     Endangered and Threatened Species                     IV470
                                                  (8)      Impacts on Commercial Fisheries                               IV471
                                                  (9)      Impacts on Recreational Resources and Activities              IV471
                                                           (a)     Beach Use                                             IV471
                                                           (b)     Marine Fishing                                        IV472
                                                  (10)     Impacts on Archaeological Resources                           IV472
                                                           (a)     Historic                                              IV472
                                                           (b)     Prehistoric                                           IV473
                                                  (11)     Impacts on Socioeconomic Conditions                           IV473
                                                           (a)     Population, Labor, and Employment                     IV473
                                                           (b)     Public Services and Infrastructure                    IV474
                                                           (c)     Social Patterns                                       IV474
                                         C.       Alternative C - The Proposed Action Excluding the Western
                                                  Naval Operations Area                                                  IV475
                                                  (1)      Impacts on Sensitive Coastal Environments                     IV475
                                                           (a)     Coastal Barrier Beaches                               IV475
                                                           (b)     Wetlands                                              IV-476
                                                  (2)      Impacts on Sensitive Offshore Resources                       IV476
                                                           (a)     Deep-water Benthic Communities                        IV476
                                                           (b)     Topographic Features                                  IV477
                                                  (3)      Impacts on Water Quality                                      IV-477
                                                  (4)      Impacts on Air Quality                                        IV-478
                                                  (5)      Impacts on Marine Mammals                                     IV-479
                                                           (a)     Nonendangered and Nonthreatened Species               IV479
                                                           (b)     Endangered and Threatened Species                     IV-479
                                                  (6)      Impacts on Marine Turtles                                     IV480
                                                  (7)      Impacts on Coastal and Marine Birds                           IV480
                                                           (a)     Nonendangered and Nonthreatened Species               IV-480
                                                           (b)     Endangered and Threatened Species                     IV480
                                                  (8)      Impacts on Commercial Fisheries                               IV-481
                                                  (9)      Impacts on Recreational Resources and Activities              IV-481
                                                           (a)     Beach Use                                             IV481
                                                           (b)     Marine Fishing                                        IV-481
                                                  (10)     Impacts on Archaeological Resources                           IV482
                                                           (a)     Historic                                              IV482
                                                           (b)     Prehistoric                                           IV-482
                                                  (11)     Impacts on Socioeconomic Conditions                           IV-483
                                                           (a)     Population, Labor, and Employment                     IV-483
                                                           (b)     Public Services and Infrastructure                    IV483
                                                           (c)     Social Patterns                                       IV484
                                         d.       Impacts from Alternative D - No Action                                 IV-484
                                         e.       Impacts of Cumulative Actions                                          IV-485
                                                  (1)      Impacts on Sensitive Coastal Environments                     IV485
                                                           (a)     Coastal Barrier Beaches                               IV485
                                                           (b)     Wetlands                                              IVAM










                 xviii

                                                    (2)      Impacts on Sensitive Offshore Resources                       IV-491
                                                             (a)     Deep-water Benthic Communities                        IV-491
                                                             (b)     Topographic Features                                  IV-492
                                                    (3)      Impacts on Water Quality                                      IV-494
                                                    (4)      Impacts on Air Quality                                        IV-499
                                                    (5)      Impacts on Marine Mammals                                     IV-504
                                                             (a)     Nonendangered and Nonthreatened Species               IV-504
                                                             (b)     Endangered and Threatened Species                     IV-506
                                                    (6)      Impacts on Marine Turtles                                     IV-508
                                                    (7)      Impacts on Coastal and Marine Birds                           IV-512
                                                             (a)     Nonendangered and Nonthreatened Species               IV-512
                                                             (b)     Endangered and Threatened Species                     IV-514
                                                    (8)      Impacts on Commercial Fisheries                               IV-517
                                                    (9)      Impacts on Recreational Resources and Activities              IV-519
                                                             (a)     Beach Use                                             IV-519
                                                             (b)     Marine Fishing                                        IV-521
                                                    (10)     Impacts on Archaeological Resources                           IV-522
                                                             (a)     Historic                                              IV-522
                                                             (b)     Prehistoric                                           IV-514
                                                    (11)     Impacts on Socioeconomic Conditions                           IV-526
                                                             (a)     Population, Labor, and Employment                     IV-526
                                                             (b)     Public Services and Infrastructure                    TV-530
                                                             (c)     Social Patterns                                       IV-532
                                           f.       Coastal Zone Management Plans and Land Use                             IV-534

                          E. ANALYSIS OF A LARGE OIL SPILL                                                                 IV-546

                                   1.      Background                                                                      IV-546

                                   2.      Scenario to be Analyzed                                                         IV-546
                                           a.       Assumptions About the Occurrence of the Spill                          IV-546
                                           b.       Assumptions About the Offshore and Shoreline Zone of Contact           IV-546
                                           C.       Assumptions About the Onshore Zone of Contact                          IV-546
                                           d.       Assumptions About the Fate of the Spilled Oil                          IV-546

                                   3.      Effects of a Large Oil Spill                                                    IV-548
                                           a.       Impacts on Sensitive Coastal Habitats                                  IV-548
                                           b.       Impacts on Water Quality                                               IV-549
                                           C.       Impacts on Air Quality                                                 IV-551
                                           d.       Impacts on Endangered and Threatened Species                           IV-552
                                           e.       Impacts on Marine Mammals                                              IV-554
                                           f.       Impacts on Coastal and Marine Birds                                    IV-554
                                           9.       Impacts on Commercial Fisheries                                        IV-555
                                           h.       Impacts on Recreational Resources and Activities                       IV-556

                 V.       CONSULTATION AND COORDINATION                                                                       V-3

                          A.       DEVELOPMENT OF THE PROPOSED ACTIONS                                                        V-3


                          B.       DEVELOPMENT OF THE DRAFT EIS                                                               V-3


                          C.       RESPONSES TO THE CALL FOR INFORMATION AND THE
                                   NOTICE OF INTENT TO PREPARE AN EIS                                                         V-3











                                                                                                               XLX


                    D.      DISTRIBUTION OF THE DRAFT EIS FOR REVIEW AND
                            COMMENT                                                                          V-6


            vi.     BIBLIOGRAPHY AND SPECIAL REFERENCES                                                      VI-3


            VII.    PREPARERS                                                                                VI-3


            VIII.   GLOSSARY                                                                                 VI-3


            Ix.     APPENDICES


                    A.      BLOCKS AFFECTED BY THE TOPOGRAPHIC FEATURES
                            STIPULATIONS IN THE CENTRAL AND WESTERN GULF
                            OF MEXICO                                                                        A-3


                    B.      BIOLOGICAL OPINIONS                                                              B-3


                    C.      RESOURCE ESTIMATES GUIDELINES                                                    C-3


                    D.      ALTERNATIVE ENERGY RESOURCES                                                     D-3


                    E.      RECENT MITIGATING MEASURES                                                       E-3












                                                                                                                                          Xxi

                FIGURES
                                                                                                                                       Page

                Figure I-1          Central and Western Gulf Planning Areas, Indicating Deferred Areas and
                                     Areas Affected by Alternatives                                                                      1-4
                Figure 11-1         Location and Lease Status of Blocks Affected by Alternative B                                      11-24
                                     (West Louisiana)
                Figure 11-2         Location and Lease Status of Blocks Affected by Alternative B                                      11-25
                                     (East Louisiana)
                Figure 11-3         Location and Lease Status of Blocks Affected by Alternative B                                      11-49
                                     (South Texas)
                Figure 11-4         Location and Lease Status of Blocks Affected by Alternative B                                      11-50
                                     (North Texas)
                Figure 111-1        Status of Air Quality in the Western and Central Planning Areas of
                                     the Gulf of Mexico                                                                              111-13
                Figure 111-2        Location and Description of Chemosynthetic: Communities in the Central
                                     Gulf of Mexico                                                                                  111-42
                Figure 111-3        Location and Description of Chemosynthetic: Communities in the
                                     Western Gulf of Mexico                                                                          111-43
                Figure 111-4        Location of Topographic Features                                                                 111-44
                Figure 111-5        Sonnier Bank and Protective Zones as Proposed by the Biological Lease
                                     Stipulation                                                                                     111-48
                Figure 111-6        Mobile Rig Utilization                                                                           111-61
                Figure 111-7        Leased Acreage                                                                                   111-62
                Figure 111-8        Oil and Gas Wellhead Prices                                                                      111-63
                Figure 111-9        Oil and Gas Production Offshore Louisiana and Texas, 1954 to 1990                                111-65
                Figure 111-10       Oil and Gas Production Values Offshore Louisiana and Texas, 1954 to 1990                         111-66
                Figure IV-1         Gulf of Mexico OCS Planning Areas and Coastal and Offshore Subareas                                IV-7
                Figure IV-2         Number of OCS Pipeline Landfalls                                                                 IV-76
                Figure IV-3         Distribution of Produced Water Discharges in Louisiana's Estuarine Basins                        IV-84
                Figure IV-4         Distribution of Produced Water Discharges in Texas Coastal Waters                                IV-84
                Figure IV-5         Location of Oil Spills (greater than or equal to 1,000 bbl) from Barges and Tankers              IV-97
                                     in or near the Gulf of Mexico from 1974 to July 1990
                Figure IV-6         Processes Affecting the Fate of Spfiled Oil                                                     IV-107
                Figure IV-7         Land Segments and Launch Sites Used in the Minerals Management Service                          IV-116
                                     Oil Spill Risk Analysis Model
                Figure IV-8         Base Case Employment Impacts from Central Gulf Sale 142                                         IV-254
                Figure IV-9         Employment Impacts from the OCS Program (Central Planning Area)                                 IV-341
                Figure IV-10        Base Case Employment Impacts from Western Gulf Sale 143                                         IV-447
                Figure IV-11        Employment Impacts from the OCS Program (Western Planning Area)                                 IV-527











                                                                                                                                                      xxiii

                 TABLES


                                                                                                                                                      Page

                 Table S-1                  Oil and Gas Resource and OCS Development Activity Estimates:
                                              Sales 142 and 143                                                                                       Xxxii
                 Table S-21                 Significant Environmental Resources and Activities Analyzed                                               xxxIiu
                 Table S-3                  Comparison and Summary of Impact Levels for Alternatives A-C and
                                              Cumulative in the Central Planning Area (Sale 142)                                                      xxxvi
                 Table S-4                  Comparison and Summary of Impact Levels for Alternatives A-D and
                                              Cumulative in the Western Planning Area (Sale 143)                                                      xiiii
                 Table 11-1                 Military Contacts                                                                                         11-21
                 Table 1114                 Climatological Data for Selected Gulf Coast Locations                                                     111-7
                 Table 111-2                National Ambient Air Quality Standards for the Five Gulf of Mexico States,
                                              with More Restrictive Standards Shown for the State of Florida                                       111-11
                 Table 111-3                Water Mass Characteristics in the Gulf of Mexico                                                       111-20
                 Table 111-4                Biotic Zones of Topographic Features with Bank Crest and Seafloor Depth
                                              in Meters                                                                                            111-47
                 Table 111-5                Marine Mammals of the Gulf of Mexico                                                                   III-so
                 Table 111-6                Population Statistics by Offshore Subarea                                                              111-68
                 Table 111-7                Labor Force and Unemployment Statistics for the Central and
                                              Western Gulf Coastal Subareas (average annual data--thousands)                                       111-69
                 Table 111-8                Industrial Composition of Central and Western Gulf Coastal
                                              Subareas for 1987                                                                                    111-71
                 Table 111-9                Population and Employment Projections for the Central and Western
                                              Gulf Coastal Subareas                                                                                111-74
                 Table 111-10               Marine Recreational Fishing Trips in the Gulf of M6:ico (1984 to 1989)
                 Table 111-11               Economic Activity Associated with Marine Recreational Fishing in the
                                              Gulf of Mexico                                                                                       111-82
                 Table IV-1                 Expected Oil and Gas Production in the Gulf of Mexico Over the
                                              Life of the Proposed Action (1993 to 2027)                                                              IV-5
                 Table IV-2                 Offshore Scenario Information Related to Sale 142 for the Years
                                              1993 to 2027                                                                                            IV-6
                 Table IV-3                 Offshore Scenario Information Related to Sale 143 for the Years
                                              1993 to 2027                                                                                            IV-8
                 Table IV-4                 Onshore Scenario Information Related to Sale 142 for the Years
                                              1993 to 2027                                                                                         IV-16
                 Table IV-5                 Onshore Scenario Information Related to Sale 143 for the Years
                                              1993 to 2027                                                                                         IV-17
                 Table IV-6                 Waterway Usage by OCS-Related Navigation Associated with Sales 142
                                              and 143 for the Years 1993 to 2027                                                                   IV-18
                 Table IV-7                 Offshore Scenario Information Associated with OCS Program Activities in
                                              the Central Planning Area for the Years 1993 to 2027                                                 IV-54
                 Table IV-8                 Offshore Scenario Information Associated with OCS Program Activities in
                                              the Western Planning Area for the Years 1993 to 2027                                                 IV-55
                 Table IV-9                 Offshore Scenario Information Associated with OCS Program Activities in
                                              the Eastern Planning Area for the Years 1993 to 2027                                                 IV-56
                 Table IV-10                Projected New Central Gulf OCS Oil and Gas Trunklines (km) by
                                              Water Depth                                                                                          IV-59
                 Table IV-11                Projected New Western Gulf OCS Oil and Gas Trunklines (km) by
                                              Water Depth                                                                                          IV-60










                  xxiv

                  Table IV-12           Onshore Scenario Information Related to OCS Program Activities in the
                                          Central Planning Area for the Years 1993 to 2027                                   IV-68
                  Table IV-13           Onshore Scenario Information Related to OCS Program Activities in the
                                          Western Planning Area for the Years 1993 to 2027                                   IV-69
                  Table IV-14           Onshore Scenario Information Related to OCS Program Activities in the
                                          Gulf of Mexico for the Years 1993 to 2027                                          IV-70
                  Table IV-15           Waterway Usage by OCS-Related Navigation Associated with the OCS
                                          Program for the Years 1993 to 2027                                                 IV-74
                  Table IV-16           Shuttle Tanker Spill Occurrence for Major Ports Receiving OCS-Produced
                                          Crude Oil (spills greater than 1,000 bbl)                                        IV-104
                  Table IV-17           Mass Balance of a Typical Gulf of Mexico Crude Oil Spill                           IV-109
                  Table IV-18           LC50 Values for Some Gulf of Mexico Marine Animals                                 IV-113
                  Table IV-19           Oil-spill Occurrence Probability Estimates for Spills Greater than or
                                          Equal to 1,000 Barrels Resulting Over the Life of the Proposed Actions,
                                          from OCS Program Activities for Proposed Sales 142 and 143                       IV-115
                  Table IV-20           Probabilities (expressed as percent chance) that an Oil Spill (greater
                                          than or equal to 1000 bbl) Starting at a Particular Location Will Contact
                                          a Certain Land Segment Within 10 Days (Sales 142 and 143)                        IV-1 17
                  Table IV-21           Probabilities (expressed as percent chance) of One or More Spills
                                          Greater than or Equal to 1,000 bbl, and the Estimated Number of
                                          Spills (mean) Occurring and Contacting Land Segments Over the
                                          Life of the Proposed Action Within 10 Days (Central Gulf Sale 142)               IV-120
                  Table IV-22           Probabilities (expressed as percent chance) of One or More Spills Greater
                                          than or Equal to 1,000 bbl and the Estimated Number of Spills (mean)
                                          Occurring and Contacting Land Segments Over the Life of the
                                          Proposed Action Within 10 Days (Western Gulf Sale 143)                           IV-123
                  Table IV-23           CGA's Oil Response Equipment                                                       IV-135
                  Table IV-24           Number of Oil Spill Cleanup Contractors by State Stocking Various
                                          Cleanup Equipment                                                                IV-136
                  Table IV-25           Summary of Cleanup Methods                                                         IV-146
                  Table IV-26           Shoreline Cleanup Methods                                                          IV-147
                  Table IV-27           Base Case OCS-Related Employment Projections (Direct +Indirect+
                                          Induced)/Central Gulf Sale 142 (person-years)                                    IV-256
                  Table IV-28           Population and Employment Impact Levels for the Base Case Scenario/
                                          Central Gulf Sale 142 (percent)                                                  IV-257
                  Table IV-29           High Case OCS-Related Employment Projections (Direct+ Indirect+
                                          Induced)/Central Gulf Sale 142 (person-years)                                    IV-259
                  Table IV-30           Population and Employment Impact Levels for the High Case Scenario/
                                          Central Gulf Sale 142 (percent)                                                  IV-260
                  Table IV-31           OCS-Rclated Employment Projections (Direct+Indirect+ Induced)/
                                          for the Cumulative Case Scenario (person-years)                                  IV-343
                  Table IV-32           Population and Employment Impact Levels for the Cumulative Case
                                          Scenario (percent)                                                               IV-343
                  Table IV-33           Base Case OCS-Related Employment Projections (Direct +Indirect+
                                          Induced)/Western Gulf Sale 143 (pcrson-years)                                    IV-448
                  Table IV-34           Population and Employment Impact Levels for the Base Case Scenario/
                                          Western Gulf Sale 143 (percent)                                                  IV-450
                  Table IV-35           High Case OCS-Related Employment Projections (Direct+ Indirect +'Induced)/
                                          Western Gulf Sale 143 (person-years)                                             IV-452
                  Table IV-36           Population and Employment Impact Levels for the High Case Scenario/
                                          Wcstcrn Gulf Sale 143 (percent)                                                  IV-453













                                                                                                                       xxv

              Table D-1            Coal Consumption by End-Use Sector (million short tons)                             D4
              Table D-2            Coal Overview (million short tons)                                                  D4
              Table D-3            Demonstrated Reserve Base of the Major Coal Provinces in the United States          D4
              Table D4             Production of Electricity from Geothermal Sources                                   D-9
              Table D-5            Solar Energy Collector to Land Ratios                                             D-11
              Table D-6            Hydroelectric Power in the United States - Total Potential                        D-12
              Table D-7            Comparison of NEPPP-Reference and High-Energy-Efficiency Cases (Quads)            D-17
              Table D-8            Replacement Energy Needs\Central and Western Planning                             D-18
                                     Areas (Base Case)












                                                                                                                           xxvii

                ABBREVIATIONS AND ACRONYMS


                ac               acre
                ACAA             Alabama Coastal Area Act
                ACAMP            Alabama Coastal Area Management Program
                ADECA            Alabama Department of Community Affairs
                ADEM             Alabama Department of Environmental Management
                AFB              Air Force Base
                APD              Application for Permit to Drill
                API              American Petroleum Institute
                ARTC             Armament Research and Test Center
                B.P.             before present
                BACT             best available control technology
                BAST             best available and safest technology
                BAT              best available technology
                Bbbl             billion barrels
                bbl              barrels
                BBO              billion barrels of oil
                bcf              billion cubic feet
                BLM              Bureau of Land Management
                BMR              Bureau of Marine Resources
                BOD              biological oxygen demand
                BOP              blowout preventer
                BPD              barrels per day
                Btu              British thermal unit
                CAA              Clean Air Act
                CAB              Coastal Area Board
                Call             Call for Information and Nominations
                CBRA             Coastal Barrier Resources Act of 1982
                CBRS             Coastal Barrier Resource System
                CEE              Center for Environmental Education
                CEI              Coastal Environments, Inc.
                CEQ              Council on Environmental Quality
                CER              categorical exclusion review
                CERCLA           Comprehensive Environmental Compensation and Liability Act
                CFR              Code of Federal Regulations
                CGA              Clean Gulf Associates
                cm               centimeter
                COE              Corps of Engineers (U.S. Army)
                CPA              Central Planning Area
                CRCPD            Conference of Radiation Program Directors
                CSA              Continental Shelf Associates
                CzM              Coastal Zone Management
                CZMA             Coastal Zone Management Act
                dB               decibel
                DER              Department of Environmental Regulation
                DM               Departmental Manual
                DOC              Department of Commerce (U.S.) (also: USDOC)
                DOCD             Development Operations Coordination Document
                DOD              Department of Defense (U.S.)
                DOE              Department of Energy (U.S.)











                 xxviii

                 DOI              Department of the Interior (U.S.) (also: USDOI)
                 DOT              Department of Transportation (U.S.) (also: USDOT)
                 DPP              Development/Production Plan
                 DST              deep stratigraphic test
                 DWG              Dispersant Working Group
                 dwt              deadweight tonnage
                 EA               environmental assessment
                 EIS              environmental impact statement
                 EP               Exploration Plan
                 EPA              Eastern Planning Area
                 ESD              Emergency Shutdown System
                 ESP              Environmental Studies Program
                 ESS              Emergency Support System
                 FAA              Federal Aviation Administration
                 FCF              Fishermen's Contingency Fund
                 FCMP             Florida Coastal Manaaement Program
                 FERC             Federal Energy Regulatory Commission
                 FMC              Fisheries Management Council
                 FMP              Fishery Management Plan
                 FR               Federal Register
                 FRS              Fast Response System
                 FSV              flow safety valve
                 ft               foot
                 FWPCA            Federal Water Pollution Control Act
                 FWS              Fish and Wildlife Service
                 FY               fiscal year
                 G&G              geological and geophysical
                 GIWW             Gulf Intracoastal Waterway
                 GMFMC            Gulf of Mexico Fishery Management Council
                 GS               Geological Survey (U.S.) (also: USGS)
                 H.R.             House Resolution (U.S. Congress)
                 ha               hectare
                 HAPC             Habitat Area of Particular Concern
                 HOSS             High-Volume Open Sea Skimmer System
                 IMCO             Intergovernmental Maritime Consultative Organization
                 in               inch
                 IPF              impact-producing factor
                 ITL              Information to Lessees and Operators
                 ITS              Incidental Take Statement
                 km               kilometer
                 kn               knots
                 LCZMP            Louisiana Coastal Zone Management Program
                 LGS              Louisiana Geological Survey
                 LNG              liquefied natural gas
                 LOOP             Louisiana Offshore Oil Port
                 LSH              level sensor high
                 LSL              level sensor low
                 LTL              Letter to Lessees and Operators
                 In               meter
                 MAFLA            Mississippi, Alabama, Florida
                 MCP              Mississippi Coastal Program
                 MFCMA            Magnuson Fishery Conservation and Management Act of 1976













           mi           mile
           MIRG         Marine Industry Research Group
           MMbbl        million barrels
           MmC          Marine Mammal Commission
           MMcf         million cubic feet
           MMRI         Mississippi Mineral Resources Institute
           MMS          Minerals Management Service
           MOU          Memorandum of Understanding
           MPA          Marine Preservation Association
           MSRC         Marine Spill Response Corporation
           mta          million metric tons annually
           MWD          measurement while drilling
           NAAQS        National Ambient Air Quality Standards
           NAS          National Academy of Sciences
           NCP          National Contingency Plan
           NCSC         Naval Command System Center
           NEPA         National Environmental Policy Act
           NERBC        New England River Basins Commission
           NHPA         National Historic Preservation Act
           NMFS         National Marine Fisheries Service
           NOAA         National Oceanic and Atmospheric Administration
           NODC         National Oceanographic Data Center
           NOI          Notice of Intent to Prepare an EIS
           NORM         naturally occurring radioactive materials
           NPA          National Planning Association Data Services, Inc.
           NPDES        National Pollution and Discharge Elimination System
           NPS          National Park Service
           NRC          National Research Council
           NRT          National Response Team
           NSPS         new source performance standards
           NTL          Notice to Lessees and Operators
           OCDM         Offshore Coastal Dispersion Model
           OCRM         Office of Ocean and Coastal Resource Management
           OCS          Outer Continental Shelf
           OCSLA        Outer Continental Shelf Lands Act
           OHMSETT      Oil and Hazardous Materials Simulated Environmental Test Tank
           OSC          On-Scene Coordinator
           OSCP         Oil Spill Contingency Plan
           OSRA         Oil Spill Risk Analysis
           OTA          Office of Technology Assessment (U.S. Congress)
           P.L.         Public Law
           PINC         Potential Incident of Noncompliance
           PIRS         Pollution Incident Reporting System
           HER          parts per million
           PSD          Prevention of Significant Deterioration
           PSH          high-prcssurc; scnsor
           PSL          low-pressure sensor
           PSV          pressure relief valve
           PWSA         Ports and Waterways Safety Act
           RCP          Regional Contingency Plan
           RCRA         Resource Conservation and Recovery Act
           RD           Regional Director












            xxx

            ROTAC       Regional Operations Technology Assessment Committee
            RRT         Regional Response Team
            RTWG        Regional Technical Working Group
            SARA        Superfund Amendments and Reauthorizations Act of 1986
            SEL         Site Evaluation List
            sic         Standard Industrial Classification
            SMA         Special Management Area
            SMSA        Standard Metropolitan Statistical Area
            SPCC        Spill Prevention Control and Countermeasure
            SPR         Strategic Petroleum Reserve
            SSSV        subsurface safety valve
            STOCS       South Texas Outer Continental Shelf
            SUSIO       State University System of Florida, Institute of Oceanography
            tcf         trillion cubic feet
            TSP         total suspended particulates
            TSS         traffic separation schemes
            U.S.        United States
            U.S.C.      United States Code
            USAF        U.S. Air Force
            USCG        U.S. Coast Guard
            USDOC       U.S. Department of Commerce (also: DOC)
            USDOI       U.S. Department of the Interior (also: DOI)
            USEPA       U.S. Environmental Protection Agency
            USGS        U.S. Geological Survey
            VOC         volatile organic compounds
            Voss        Vessel of Opportunity Skimming System
            WPA         Western Planning Area
            yd          yard
            yr          year











                                                                                                                               xxxi

               SUMMARY

                   This environmental impact statement (EIS) addresses two proposed Federal actions, lease Sales 142 and
               143, that will offer for lease Gulf of Mexico Outer Continental Shelf (OCS) areas that may contain
               economically recoverable oil and gas resources. The lease sales are proposed for 1993 and include lease blocks
               in the Central Gulf of Mexico Planning Area (CPA) and Western Gulf of Mexico Planning Area (WPA).
               Figure I-1 provides statistics on the leasing status in these two areas. Approximately 9,900 blocks will be
               available for lease under the two proposed actions; only a small percentage is expected to be actually leased.
               On average, 434 blocks in the Central Gulf and 264 blocks in the Western Gulf have been leased in individual
               Gulf of Mexico OCS lease sales since 1984. Of the blocks that will be leased as a result of the two proposed
               actions, only a portion will be drilled and result in subsequent production.
                   The analytical methods used in this EIS have been formulated over a period of years. The first step of
               the analysis is the identification of significant environmental and socioeconomic resources through the scoping
               process outlined in Section I.13.2.c.(1). A range of energy resource estimates is derived from geologic and
               economic assumptions and alternatives to the proposed action are established. Estimated levels of exploration
               and development activity are assumed for the purposes of the analysis. An analysis of the potential interactio    in
               between the significant environmental resources and the OCS-related activities is then conducted.
                   The scoping process (Section I.B.2.) was used to obtain information and comments on the proposed actions
               and the potential environmental effects from diverse interests, including the affected States, Federal agencies,
               the petroleum industry, environmental and public interest groups, and concerned individuals. The input from
               these sources aided in the identification of significant issues, possible alternatives to the proposed actions, and
               potential mitigating measures. The following are brief descriptions of the proposed actions, alternatives,
               mitigating measures, and issues addressed in this EIS.

               Proposed Actions and Alternatives

                   Proposed Central Gulf Sale 142 and the Alternatives

                   Alternative A (Proposed Central Gulf Sale 142) is scheduled to be held in March 1993 and may offer
               approximately 5,194 unleased blocks (as of January 1992) comprising about 28.0 million acres in the CPA- This
               area includes acreage located from 3 to 219 mi offshore in water depths ranging from 13 to over 11,000 ft.
               There are no areas deferred from the CPA- This alternative includes existing regulations and proposed lease
               stipulations designed to reduce environmental risks. It is estimated that the proposal could result in the
               production of 0.14 billion bbl of oil (BBO) and 1.40 trillion cubic feet (tco of gas.
                   Alternative B (77ze Proposed Action Fxcluding the Blocks Near Biologically Sensitive Topographic Features)
               would delete all unleased blocks of the 167 total blocks on or near biologically sensitive areas of the
               topographic features in the Central Gulf. All of the remaining unleased area would be available for leasing.
                   Alternative C (No Action) equates to cancellation of the sale. Neither potential environmental effects nor
               oil and gas production, which could result from the proposed action, would occur. Alternative energy resources
               that might be used to replace energy resources lost by cancellation of this sale are discussed in Appendix D.

                   Proposed Western Gulf Sale 143 and the Alternatives

                   Alternative A (Proposed Western Gulf Sale 143) is scheduled to be held in August 1993 and may offer
               approximately 4,715 unleased blocks (as of January 1992), comprising about 25.8 million acres in the WPA.
               This area is located from 9 to 221 mi offshore in water depths ranging from 26 to over 9,000 ft. Excluded from
               this proposed action are Blocks A-375 (East Flower Garden Bank) and A-398 (West Flower Garden Bank)
               in the High Island Area; these blocks are deferred because of the environmentally sensitive nature of the
               biological communities located there. The East and West Flower Garden Banks have officially been designated
               as marine sanctuaries. This alternative includes existing regulations and proposed lease stipulations designed











                   xxxii

                   to reduce environmental risks. It is estimated that the proposal could result in the production of 0.05 BBO
                   and 0.74 tcf of gas.
                       Alternative B (Re Proposed Action Excluding the Blocks Near Biologically Sensitive Topographic Features)
                   would delete all unleased blocks of the 200 total blocks on or near biologically sensitive areas of the
                   topographic features in the Western Gulf. All of the remaining unleased areas would be available for leasing,
                   except for the two deferred blocks at the Flower Garden Banks.
                       Alternative C (Re ProposedAction ErcludingBlocks Contained in the Western Naval OpetationsArea) would
                   delete approximately 340 blocks contained in the Western Naval Operations Area near Corpus Christi, Texas.
                       Alternative D (No Action) equates to cancellation of the sale. Neither potential environmental effects nor
                   oil and gas production, which could result from the proposed action, would occur. Alternative energy resources
                   that might be used to replace energy resources lost by cancellation of this sale are discussed in Appendix D.

                   Mitigating Measures

                       Four potential stipulations have historically been applied to appropriate Gulf OCS leases, and these are
                   analyzed as part of the proposed actions. These stipulations are the Live Bottom (Pinnacle Trend),
                   Topographic Features, Archaeological Resource, and Military Area Stipulations for the Central Gulf sale; and
                   the Topographic Features, Archaeological Resource, and Military Area Stipulations for the Western Gulf sale.
                   Actual application of these stipulations to leases that may result from the proposed actions are options
                   available to the Secretary of the Interior.

                   Action Scenarios Analged

                       Oil and gas resources estimated to be leased and developed from the proposed lease sales are the basis
                   for environmental analyses of resources that may be impacted by OCS activities. These estimates, based on
                   many factors such as geologic structure, economic assumptions, proximity to existing development, etc., fall
                   within a large range. From these ranges, two scenarios are developed. The primary scenario is called the Base
                   Case and assumes the mean or expected amounts of undiscovered, unleased hydrocarbon resources, and
                   resultant development activities. The second scenario is the High Case, which is the relatively less likely
                   possibility that the upper end of the range of energy resource estimates will be leased, discovered, and
                   developed.
                       An additional analysis is given of the environmental impacts that result from the incremental impact of the
                   lease sales when added to all past, present, and reasonably foreseeable future human activities. The outcome
                   of this analysis is labeled the cumulative impact on the particular resource under discussionand covers a period
                   of 35 years. This term, however, should not be confused with the cumulative impacts attributable to OCS
                   activities.
                       The environmental analyses are based on levels of assumed development activities correlated with the
                   amount of resources estimated to be leased (Table S-1). These activities include the number of platforms,
                   wells, pipelines, service vessel trips, etc. The interaction of all OCS activities that result from the lease sale
                   with environmental resources is analyzed.

                   Significant Issues

                       Table S-2 lists the resources and activities determined through the scoping process to be sufficiently
                   important to warrant inclusion in this environmental analysis. The scoping process is an ongoing effort, and
                   contacts are made with other Federal and State Agencies, the public, academia, and environmental groups to
                   identify those resources about which there is concern. This process determines the significant resources and
                   activities to be addressed in the EIS.











                                                                                                                    xxxiii

              Impact Conclusions

                  Tables S-3 and S-4 provide a summary of the impacts of proposed Sales 142 and 143 and their alternatives
              under the Base Case, High Case, and cumulative analyses.










                 xxxiv


















                                                                     Table S-1


                       Oil and Gas Resource and OCS Development Activity Estimates: Sales 142 and 143

                                                                      Central               Western
                                                                      Planning              Planning
                                                                        Area                  Area
                                                                        Sale 142            Sale 143
                                                                      Base Case            Base Case


              Acreage Available for Leasing'
                (million of acres)                                       28.0                 25.8
              Resources Expected to be Developed2
                Oil (billion barrels)                                     0.14                 0.05
                Gas (trillion cubic feet)                                 1.40                 0.74


              OCS Development Activity
                Exploration and Delineation Wells                       340                 210
                Platform Installations                                    30                  10
                Development Wells                                       250                 110
                Pipelines (kilometers)                                  240                   80


              'Unleased acreage available for leasing (deferred acreage not included) as of January 1992 fbir the Central
               and Western Gulf sales.
              2The methodology used to estimate resources is explained in Appendix C.

              Source: USDOI, Minerals Management Service, Gulf of Mexico OCS Region estimates, 1991.













                                                                                                                     xxxv















                                                              Table S-2


                                     Significant Environmental Resources and Activities Analyzed

                            Central Gulf Sale 142                                       Western Gulf Sale 143


                Coastal Environments                                         Coastal Environments
                 Coastal Barrier Beaches                                       Coastal Barrier Beaches
                 Wetlands                                                      Wetlands
                Offshore Environments                                        Offshore Environments
                 Live-bottoms (Pinnacle Trend)                                 Deep-water Benthic Communities
                 Deep-water Benthic Communities                                Topographic Features
                 Topographic Features                                        Water Quality
                Water Quality                                                Air Quality
                Air Quality                                                  Marine Mammals
                Coastal and Marine Mammals                                     Nonendangered and Nonthreatened Species
                 Marine Mammals                                                Endangered and Threatened Species
                   Nonendangered and Nonthreatened                           Marine Turtles
                   Species                                                   Coastal and Marine Birds
                   Endangered and Threatened Species                           Nonendangered and Nonthreatened Species
                 Alabama, Choctawhatchee, and Perdido                          Endangered and Threatened Species
                    Key Beach Mice                                           Commercial Fisheries
                Marine Turtles                                               Recreational Resources and Activities
                Coastal and Marine Birds                                       Beach Use
                 Nonendangered and Nonthreatened Species                       Marine Fishing
                 Endangered and Threatened Species                           Archaeological Resources
                Gulf Sturgeon                                                  Historic
                Commercial Fisheries                                           Prehistoric
                Recreational Resources and Activities                        Socioeconomic Conditions
                 Beach Use                                                     Population, Labor, and Employment
                 Marine Fishing                                                Public Services and Infrastructure
                Archaeological Resources                                       Social Patterns
                 Historic
                 Prehistoric
                Socioeconomic Conditions
                 Population, Labor, and Employment
                 Public Services and Infrastructure
                 Social Patterns























                                                                                                                                        Table S-3


                                                                                                             Comparison and Summary of Impacts for Alternatives A-C
                                                                                                              and Cumulative in the Central Planning Area (Sale 142)

                             Alternatives                                                                                           Resource Categories

                                                                Coastal Barrier Beaches                                                            Wetlands                                                       Live Bottom (Pinnacle Trend)

                             Alternative A        The proposed action is not expected to result in           The proposed action is expected to result in dieback and mortality of 10-15 ha             The impact of the proposed action is expected
                             Base Case            permanent      alterations     of    barrier     beach     of wetlands vegetation as a result of contacts from onshore oil spills. All but 2          to be such that any changes in the regional
                                                  configurations, except        in   localized areas         ha of these wetlands will recover within 10 years; the remaining 2 ha will be              physical integrity, species diversity, or biological
                                                  downdrift from navigation channels that have               converted to open water. About 5.5 ha of wetlands are projected to be eroded               productivity of the Pinnacle Trend region would
                                                  been dredged and deepened. The contributionto              along channel margins as a result of OCS vessel wake erosion, and 3.5 ha of                recover to pre-impact conditions in less than 2
                                                  this localized erosion is expected to be less than         wetlands are projected to be created as a result of beneficial disposal ofdredged          years, more probably on the order of 2-4
                                                  1 percent.                                                 material from channel-deepening projects.                                                  months.


                             Alternative A        Same as Alternative A - Base Case.                         The proposed action is expected to result in dieback and mortality of 10-15 ha             Same as Alternative A - Base Case.
                             High Case                                                                       of wetlands vegetation as a result of contacts from onshore oil spills. All but 2
                                                                                                             ha of these wetlands will recover within 10 years; the remaining 2 ha will be
                                                                                                             converted to open water. About I I ha of wetlands are projected to be eroded
                                                                                                             along channel margins as a result of OCS vessel wake erosion, and 7 ha of
                                                                                                             wetlands are projected to be created as a result ofbeneficial disposal of dredged
                                                                                                             material from channel-deepening projects.

                             Alternative BI       Same as Alternative A - Base Case.                         Same as Alternative A - Base Case.                                                         Same as Alternative A - Base Case.


                             Alternative C2       No effect.                                                 No effect.                                                                                 No effect.

                             Cumulative           The observed erosional trend of barrier features           Large losses of wetlands are expected to continue to occur. The main cause of              The cumulative impacts are expected to be such
                             Impacts              is expected to continue in onshore Subareas C-1,           these losses, particularly in coastal Louisiana where the largest amount of                that this damage to one or more components of
                                                  C-2, and C-3. The major causes of these impacts            wetlands will be lost, is sediment deprivation and rapid coastal submergence.              a few regionally common habitats or
                                                  are sediment deficits and relative sea-level rise.         Other contributing factors include tideland oil and gas development, the erosion           communities results in changes to physical
                                                                                                             of navigation channel margins, and, to a lesser extent, impacts from oil spills.           integrity, species diversity, or biological
                                                                                                                                                                                                        productivity that exceeds natural variability
                                                                                                                                                                                                        (observed prior to the damage); recovery to
                                                                                                                                                                                                        pre-impact conditions is expected to take longer
                                                                                                                                                                                                        than 10 years.

















                    Table S-3 Comparison and Summary of Impacts for Alternatives A-C and Cumulative in the Central Planning Area (Sale 142) (continued)

                    Alternatives                                                                                        Resource Categories

                                                       Deep-water Benthic                                              Topographic Features                                                               Water Quality
                                                           Communities

                        Alternative A       ne proposed action is expected to cause         The proposed action is     expected to cause little to no damage to the           An identifiable change to the ambient concentration of one or more
                        Base Case           little damage to the physical integrity,        physical integrity, species diversity, or biological productivity of the          water quality parameters will be evident up to several hundred to
                                            species     diversity,    or     biological     habitats of the topographic features of the Gulf of Mexico. Small areas           1,000 m from the source and for a period lasting up to several weeks
                                            productivity of either the widespread,          of 5-10 M2 would be impacted, and recovery from this damage to pre-               in duration in marine and coastal waters.          Chronic, low-level
                                            low-density chemosynthetic communities          impact conditions is expected to take less than 2 years, probably on the          pollution related to the proposal win occur throughout the life of the
                                            or the rarer, widely scattered, high-           order of 24 weeks.                                                                proposed action.
                                            density Bush Hill-qr chemosynthetic
                                            communities.        Recovery from any
                                            damage is expected to take less than 2
                                            years.

                        Alternative A       Same as Alternative A - Base Case.              Same as Alternative A - Base Case.                                                Same as Alternative A - Base Case.
                        High Case

                        Alternative BI      Same as Alternative A - Base Case.              Alternative B is expected to cause little to no damage to the physical            Same as Alternative A - Base Case.
                                                                                            integrity, species diversity, or biological prGductivityofthe habitats ofthe
                                                                                            topographic features of the Gulf of Mexico. Small areas of 5-10 M2
                                                                                            would be impacted, and recovery from this damage to pre-impact
                                                                                            conditions is expected to take less than 2 years, probably on the order
                                                                                            of 24 weeks. Selection of Alternative B would preclude oil and gas
                                                                                            operations in the unleased blocks affected by the proposed Topographic
                                                                                            Features Stipulation.

                        Alternative C'      No effect.                                      No effect.                                                                        No effect.

                        Cumulative          The cumulative impacts are expected to          The Cumulative scenario is expected to cause little to no damage to the           Cumulative demands resulting from the proposal are expected to
                        Impacts             cause little damage to the physical             physical integrity, species diversity, or biological productivity of the          result in significant changes to the ambient concentration of one or
                                            integrity, species diversity, or biological     habitats of the topographic features of the Gulf of Mexico. Smallareas            more water quality parameters up to several hundred to 1,000 in from
                                            productivity of either the widespread,          of 5-10 ml would be impacted, and recovery from this damage to pre.               the source of activities and for a period lasting up to several weeks or
                                            low-density chemosynthetic communities          impact conditions is expected to take less than 2 years, probably on the          months in duration. Chronic, low-level pollution related to the
                                            or the rarer, widely scattered, high-           order of 24 weeks.                                                                proposal will occur throughout the life of the proposed action. Overall
                                            density Bush Hill-type chemosynthetic                                                                                             cumulative impacts, which include the effects of non-OCS-related
                                            communities.       Recovery from any                                                                                              factors and OCS activities, will signifi- cantly degrade water quality,
                                            damage is expected to take less than 2                                                                                            primarily within the Gulf of Mexico's coastal zone, in highly urbanized
                                            years.                                                                                                                            and industrialized coastal areas. Maritime activities will contribute to
                                                                                                                                                                              water quality degradation near ports and major navigation channels.
                                                                                                                                                                              In restricted or poorly flushed coastal waterbodies, localized increases
                                                                                                                                                                              in pollutant concentrations may be severe and persist for months or
                                                                                                                                                                              longer. Chronic, low-level pollution will continue to persist in marine
                                                                                                                                                                              and coastal waters.


















                             Table S-3 Comparison and Summary of Impacts for Alternatives A-C and Cumulative in the Central Planning Area (Sale 142) (continued)

                             Alternatives                                                                                                 Resource Categories

                                                                                                                                                                     Marine Mammals
                                                                                  Air Quality                                     Nonendangered and Nonthreatened                       Endangered and Threatened                       Alabama, Choctawhatchee, and
                                                                                                                                                                                                                                            Perdido Key Beach Mice
                                                                                                                                  The impact on nonendangered and                   The impact on endangered and
                             Alternative A               Emission of pollutants into the atmosphere are                           nonthreatened marine mammals                      threatened marine mammals within                  The impact on beach mice within
                             Base Case                   expected to have concentrations that would not change                    within the potentially affected area              the potentiahy affected area is                   the potentially affected area is
                                                         onshore air quality classifications. An increase in                      is expected to result in sublethal                expected to result in sublethal                   "peeled to result in sublethal
                                                         onshore concentrations of air pollutants is estimated to                 effects that are chronic and could                effects that are chronic and could                effects that seldom occur and may
                                                         be about I jLgm-3. This concentration will have minimal                  result in persistent physiological or             result in persistent physiological or             cause short-term physiological or
                                                         impacts during winter because onshore winds occur                        behavioral changes, as well as some               behavioral changes, as well as some               behavioral changes.
                                                         only about 37 percent of the time, with maximum                          degree of avoidance of the                        degree of avoidance            of the
                                                         impacts in summer when onshore winds occur 61                            impacted area.                                    impacted area.
                                                         percent of the time.

                             Alternative A               Same as Alternative A - Base Case.                                       Same as Alternative A - Base Case.                Same as Alternative A - Base Case.                Same as Alternative A - Base Case.
                             High Case

                             Alternative BI              Same as Alternative A - Base Case.                                       Same as Alternative A - Base Case.                Same as Alternative A - Base Case.                Same as Alternative A - Base Case.


                             Alternative C'              No effect.                                                               No effect.                                        No effect.                                        No effect.

                             Cumulative Impacts          Emission of pollutants into the atmosphere from the                      The impact on nonendangered and                   The impact on endangered and                      The cumulative impact on beach
                                                         activities assumed for the OCS program are expected                      nonthreatcned marine mammals                      threatened marine mammals within                  mice within the potentially affected
                                                         to have concentrations that may change onshore air                       within the potentially affected area              the potentially affected area is                  area is expected to result in a
                                                         quality    classifications.       Increases     in    onshore            is expected to result in a decline in             expected to result in a decline in                decline in species numbers or a
                                                         concentrations of air pollutants are estimated to be                     species numbers or a temporary                    species numbers or a temporary                    temporary displacement from their
                                                         between I and 14.5 jugml (box model steady                               displacement from their current                   displacement from their current                   current distribution, a decline or
                                                         concentrations). This concentration will have minimal                    distribution,      a    decline       or          distribution,      a    decline       or          displacement that will last more
                                                         impact during winter because onshore winds occur only                    displacement that will last more                  displacement that will last more                  than one generation.
                                                         37 percent of the time, with maximum impacts in                          than one generation.                              than one generation.
                                                         summer when onshore winds occur 61 percent of the
                                                         time.



















                           Table S-3 Comparison and Summary of Impacts for Alternatives A-C and Cumulative in the Central Planning Area (Sale 142) (continued)

                           Alternatives                                                                                  Resource Categories

                                                                                                                                            Coastal and Marine Birds
                                                                     Marine Turtles                        Nonendangered and Nonthreatened                         Endangered and Threatened                                    Gulf Sturgeon

                           Alternative A              The impact on marine turtles within the            'Me impact on nonendangered and                   The impact on endangered and threatened            The impact on the Gulf sturgeon within the
                           Base Case                  potentially affected area is expected to           nonthreatened coastal and marine birds            birds within the potentially affected area is      potentially affected area is expected to result
                                                      result in sublethal effects that are chronic       within the potentially affected area is           expected to result in no discernible decline       in sublethal effects and cause short-term
                                                      and could result in persistent physiological       expected to result in no discernible decline      in a population or species and no change           physiological or behavioral changes.
                                                      or behavioral changes.                             in a population or species and no change          in distribution and/or abundanceon a local
                                                                                                         in distribution and/or abundanceon a local        or regional scale. Individuals experiencing
                                                                                                         or regional scale. Individuals experiencing       sublethal     effects    wilt   recover       to
                                                                                                         sublethal     effects    will   recover      to   predisturbance condition in less than one
                                                                                                         pre"turbance condition in less than one           generation.
                                                                                                         generation.

                           Alternative A              Same as Alternative A - Base Case.                 Same as Alternative A - Base Case.                Same as Alternative A - Base Case.                 Same as Alternative A - Base Case.
                           High Case



                           Alternative BI             Same as Alternative A - Base Case.                 Same as Alternative A - Base Case.                Same as Alternative A - Base Case.                 Same as Alternative A - Base Case.


                           Alternative C'             No effect.                                         No effect.                                        No effect.                                         No effect.


                           Cumulative Impacts         The cumulative impact on marine turtles            The cumulative effect on coastal and              The impact on endangered and threatened            The impact on the Gulf sturgeon within the
                                                      within the potentially affected area is            marine birds within the potentially affected      birds within the potentially affected area is      potentially affected area is expected to result
                                                      expected to result in a decline in species         area is expected to result in a discernible       expected to result in a decline in species         in a decline in species number or a temporary
                                                      numbers or a temporary displacement                decline in a local coastal or marine bird         numberor a temporary displacement from             displacement from their current distribution,
                                                      from their current distribution, a decline         population or species, resulting in a             their current distribution, a decline or           a decline or displacement that will last more
                                                      or displacement that will last more than           change in distribution or abundance.              displacement that will last more than one          than one generation.
                                                      one generation.                                    Recruitment will return the population or         generation.
                                                                                                         affected species to their pre-impact level
                                                                                                         and/or condition within one to two
                                                                                                         generations. It is doubtful that this impact
                                                                                                         will affect regional populations.














                                                                                                                                                                                                                                                        >0









                           Table S-3 Comparison and Summary of Impacts for Alternatives A-C and Cumulative in the Central Planning Area (Sale 142) (continued)

                           Alternatives                                                                                       Resource Categories


                                                                       Commercial Fisheries                                                Beach Use                                                                  Marine Fishing

                           Alternative A             The impact on commercial fisheries within the                  The proposed action is expected to result in minor                              Platforms installed within 30 mi of shore will
                           Base Case                 potentially affected area is expected to result in a short-    pollution events and nearshore operations that may                              attract fish and are likely to attract fishermen and
                                                     term decrease in a portion of a population of                  adversely affect the enjoyment of some beach users on                           improve fishing for a period of about 20 years,
                                                     commercial importance, in an essential habitat, or in          Texas and Louisiana beaches.                                                    but are unlikely to affect offshore fishing patterns
                                                     commercial fisheries on a local scale. Any affected                                                                                            in general unless the platforms are installed in
                                                     population is expected to recover to predisturbance                                                                                            nearshore locations where no platforms currently
                                                     condition in one generation.                                                                                                                   exist.

                           Alternative A             Same as Alternative A - Base Case.                             Same as Alternative A - Base Case.                                              The High Case scenario will likely result in a few
                           High Case                                                                                                                                                                more platforms that will be productive sports fish
                                                                                                                                                                                                    areas accessible to and used by offshore
                                                                                                                                                                                                    rccreational fishermen throughout the CPA, but
                                                                                                                                                                                                    it is unlikely to have a detectable impact on the
                                                                                                                                                                                                    recreational fishing industry at the regional level.
                                                                                                                                                                                                    A few local fishing markets could suffer short-
                                                                                                                                                                                                    term (up to one month) loss of business from a
                                                                                                                                                                                                    major pollution event; however, these same
                                                                                                                                                                                                    markets should experience long-term (15-20 yrs)
                                                                                                                                                                                                    benefit from platform installations accessible to
                                                                                                                                                                                                    local fishermen.


                           Alternative BI            Same as Alternative A - Base Case.                             Same as Alternative A - Base Case.                                              Same as Alternative A - Base Case.


                           Alternative C'            No effect.                                                     No effect.                                                                      No effect.

                           Cumulative Impacts        The cumulative effect on the commercial Fishing industry       Although trash and accidental oil spills will continue to                       Continued offshore oil and gas development over
                                                     within the potentially affected area is expected to result     affect the ambience of recreational beaches between                             the next 35 years will continue to support,
                                                     in a discernible decline in Dovulations of commercial          Alabama and Texas, the level nf Chronic pollkiti n                              maintpin, and fiqq'litnte niFfishnre recreatinnal
                                                     importance, in the quality of essential habitats, or in        should decline during the life of the proposed action.                          fishing in the CPA and will extend the time
                                                     commercial fishing activity. Recruitment will return any       Beach use at the regional level is unlikely to change;                          offshore oil and gas structures are a focus of
                                                     affected population, habitat, or activity to pre-impact        however, closure of specific beached or parks directly                          offshore fishing activity.
                                                     level and/or condition within two to three generations.        impacted by one or two oil spills greater than or equal
                                                                                                                    to 1,000 bbl is likely during cleanup operations.























                         Table S-3 Comparison and Summary of Impacts for Alternatives A-C and Cumulative in the Central Planning Area (Sale 142) (continued)

                         Alternatives                                                                                     Resource Categories

                                                                                                                                                     Archaeological Resources

                                                                                                                                  Historic                                                                   Prehistoric

                         Alternative A                                                               There is a very small possibility of an impact between OCS oil              There is a very small possibility of an impact between OCS oil
                         Base Case                                                                   and gas activities and a historic shipwreck or site. Should such            and gas activities and a prehistoric site. Should such an impact
                                                                                                     an impact occur, unique or significant historic archaeological              occur, unique or significant prehistoric archaeological
                                                                                                     information could be lost.                                                  information could be lost.
                         AJternative A
                         High Case                                                                   Same as Alternative A - Base Case.                                          Same as Alternative A - Base Case.

                         Alternative BI
                                                                                                     Same as Alternative A - Base Case.                                          Same as Alternative A - Base Cam
                         Alternative C2
                                                                                                     No effect.                                                                  No effect.
                         Cumulative Impacts
                                                                                                     The total of OCS program and non-program related impact-                    The total of OCS program and non-program-related impact-
                                                                                                     producing factors has likely resulted in and may yet result in loss         producing factors has likely resulted in and mayyet result in loss
                                                                                                     of significant or unique historic archaeological information.               of significant or unique prehistoric archaeological information.















                            Table S-3 Comparison and Summary of Impacts for Alternatives A-C and Cumulative in the Central Planning Area (Sale 142) (continued)


                            Alternatives                                                                                            Resource Categories

                                                                                                                                   Socioeconomic Conditions

                                                                     Population, Labor, and Employment                                        Public Services and Infrastructure                                                 Social Patterns

                            Alternative A                    The impact in the Central Gulf on the population,                  Population and employment impacts will not result in                          It is expected that no net migration will occur as
                            Base Case                        labor, and employment of the counties and                          disruptions to community infrastructure and public services                   a result of the proposed action.           Deleterious
                                                             parishes of the Central and Western Gulf coastal                   beyond what is anticipated by in-place planning and                           impacts to social patterns are expected to occur
                                                             impact area is expected to be less than I percent of               development agencies.                                                         in some individual cases as a result of "tended
                                                             the levels expected in the absence of the proposal.                                                                                              work schedules, displacement from traditional
                                                                                                                                                                                                              occupations, and relative wages.

                            Alternative A                    Same as Alternative A - Base Case.                                 Same as Alternative A - Base Case.                                            Same as Alternative A - Base Case.
                            High Case

                            Alternative BI                   Same as Alternative A - Base Case.                                 Same as Alternative A - Base Case.                                            Same as Alternative A - Base Case.

                            Alternative C'                   No effect.                                                         No effect.                                                                    No effect.

                            Cumulative Impacts               On a regional level, the cumulative impact from                    The cumulative impact is expected to result in deteriorating                  It is expected that some loss of traditional
                                                             prior sales, the proposed actions, and future sales                conditions of existing infrastructure and difficulties in                     occupations will occur. Deleterious impacts to
                                                             on the population, labor, and employment of the                    delivering satisfactory levels of public services.                            cultural heritage and family life are also expected
                                                             counties and parishes of the Central Gulf coastal                                                                                                to occur in some individual cases. It is expected
                                                             impact     area    is significant, amounting to                                                                                                  that these impacts will be greatest in coastal
                                                             approximately        3,310,400     person-years        of                                                                                        Subareas C-1, C-2, and C-3.
                                                             employment over the life of the proposed action
                                                             plus at least an additional 11,050 person-years of
                                                             employment associated with the clean-up of three
                                                             oil spills.    Locally, the cumulative impact to
                                                             population, labor, and employment is higher for
                                                             coastal Subareas C-I and C-2 along the western
                                                             and central Louisiana coastline, lower for coastal
                                                             Subarea C-3 in southeast Louisiana, and lowest for
                                                             coastal Subarea C-4 in Mississippi and Alabama.
                                                             E m p loyrnc n t n e ed s il L 5 u p p0 In - I - - _: I - - @ - - -
                                                                                                UL W%-a V11 411U 64b
                                                             activity are likely to be met with the existing
                                                             population and available labor force.


                            'Alternative B - The Proposed Action Excluding the Blocks Near Biologically Sensitive Topographic Features.
                            'Alternative C - No Action.





















                                                                                                                                        Table S-4
                                                                                                             Comparison and Summary of Impacts for Alternatives A-D
                                                                                                              and Cumulative in the Western Planning Area (Sale 143)

                              Alternatives                                                                                          Resource Categories

                                                             Coastal Barrier Beaches                                     Wetlands                              Deep-water Benthic Communities                           Topographic Features

                         Alternative A             The proposed action is not expected to             The proposed action is expected to result in        The proposed action is expected to cause           The proposed action is expected to cause
                         Base Case                 result in permanent alterations of barrier         no permanent alterations ofwetland habitat,         little damage to the physical integrity,           little to no damage to the physical integrity,
                                                   beach configurations, except in localized          except for the erosion of less than I ha of         species diversity, or biological productivity of   species diversity, or biological productivity
                                                   areas downdrift from channels that have            wetlands along navigation channel margins.          either    the widespread,          low-density     of the habitats of the topographic features
                                                   been dredged and deepened.                  The    These losses could be offset or even                chemosynthetic communities or the rare,            of the Gulf of Mexico. Small areas of 5-10
                                                   contribution to this localized erosion is          exceeded by wetland gains from the                  widely scattered, high-density Bush Hill-type      m2 would be impacted, and recovery from
                                                   expected to be less than I percent.                beneficial disposal of dredged material             chemosynthetic communities.           Recovery     this damage to pre-impact conditions is
                                                                                                      generated during channel maintenance and            from any damage is expected to take less           expected to take less than 2 years, probably
                                                                                                      deepening operations.                               than 2 years.                                      on the order of 2-4 weeks.
                         Alternative A             Same as Alternative A - Base Case.                 The proposed action is expected to result in        Same as Alternative A - Base Case.                 Same as Alternative A - Base Case.
                         High Case                                                                    no permanent alterations ofwetland habitat,
                                                                                                      except for the erosion of less than 2 ha of
                                                                                                      wetlands along navigation channel margins.
                                                                                                      These losses could be offset or even
                                                                                                      exceeded by wetland gains from the
                                                                                                      beneficial disposal of dredged material
                                                                                                      generated during channel maintenance and
                                                                                                      deepening operations.

                         Alternative BI            Same as Alternative A - Base Case.                 Same as AJternative A - Base Case.                  Same as Alternative A - Base Case.                 Alternative B is expected to cause little to
                                                                                                                                                                                                             no damage to the physical integrity, species
                                                                                                                                                                                                             diversity, or biological productivity of the
                                                                                                                                                                                                             habitats of the topographic features of the
                                                                                                                                                                                                             Gulf of Mexico. Small areas of 5-10 M2
                                                                                                                                                                                                             would be impacted, and recovery from this
                                                                                                                                                                                                             damage to pre-impact conditions is
                                                                                                                                                                                                             expected to take less than 2 years, probably
                                                                                                                                                                                                             on the order of 24 weeks. Selection of
                                                                                                                                                                                                             Alternative B would preclude oil and gas
                                                                                                                                                                                                             operations in the unleased blocks affected
                                                                                                                                                                                                             by the proposed Topographic Features
                                                                                                                                                                                                             Stipulation.

                         Alternative C2            Same as Alternative A - Base Case.                 Same as Alternative A - Base Case.                  Same as Alternative A - Base Case.                 Same as Alternative A - Base Case.




















                          Table S-4 Comparison and Summary of Impacts for Alternatives A-D and Cumulative in the Western Planning Area (Sale 143) (continued)
                          Alternatives                                                                                         Resource Categories

                                                             Coastal Barrier Beaches                                    Wetlands                              Deep-Water Benthic Communities                            Topographic Features

                          Alternative D3           No effect.                                         No effect.                                         No effect.                                         No effect.
                          Cumulative Impacts       Ile observed erosional trend of barrier            Losses ofwetlands are expected to continue.        The Cumulative Scenario is expected to             The Cumulative Scenario is expected to
                                                   features will continue along the Gulf Coast        The major cause of this loss is expected to        cause little damage to the physical integrity,     cause little to no damage to physical
                                                   in the area of potential impact. The major         be coastal submergence.                            species diversity, or biological productivity of   integrity, species diversity, or biological
                                                   causes of the impacts is the reduction in                                                             either    the widespread,          low-density     productivrity of the habitats of the
                                                   sediment being delivered to the coastal                                                               chemosynthetic communities or the rare,            topographic features of the Gulf of Mexico.
                                                   littoral system, sea-level rise, the effects of                                                       widely scattered, high-density Bush Hill-type      Small areas of 5-10 M2 would be impacted,
                                                   navigational and erosion control structures,                                                          chemosynthetic communities.           Recovery     and recovery from this damage to pre-
                                                   and some recreational impacts.                                                                        from any damage is expected to take less           impact conditions is expected to take less
                                                                                                                                                         than 2 years.                                      than 2 years, probably on the order of 24
                                                                                                                                                                                                            weeks.

















                             Table S-4 Comparison and Summary of Impacts for Alternatives A-D and Cumulative in the Western Planning Area (Sale 143) (continued)

                             Alternatives                                                                                          Resource Categories

                                                                                                                                                                                                    Marine Mammals
                                                                      Water Quality                                        Air Quality                           Nonendangered and Nonthreatcried                        Endangered and Threatened

                             Alternative A           An identifiable change to the ambient                Emissions of pollutants into the atmosphere        The impact on noncndangered and                     The impact on endangered and threatened
                             Base Case               concentration of one or more water quality           are expected to have concentrations that           nonthreatened marine mammals within the             marine mammals within the potentially
                                                     parameters will be evident up to several             would not change onshore air quality               potentially affected area is expected to            affected area is expected to result in
                                                     hundred to 1,000 m from the source and for           classifications.     Increase in onshore           result in sublethal effects that occur              sublethal effects that occur periodicallyand
                                                     a period lasting up to several weeks in              concentrations of air         pollutants are       periodically and result in short-term               result in short-term physiological or
                                                     duration in marine and coastal waters.               estimated to be about 1 ggm-3.             This    physiological or behavioral changes, as well        behavioral changes, as well as some degree
                                                     Chronic, low-level pollution related to the          concentration will have minimal impacts            as some degree of avoidance of the                  of avoidance of the impacted area(s).
                                                     proposal will occur throughout the life of           during winter because onshore winds occur          impacted area(s).
                                                     the proposed action.                                 only about 34 percent of the time, with
                                                                                                          maximum impacts in summer when onshore
                                                                                                          winds occur 85 percent of the time.



                             Alternative A           Same as Alternative A - Base Case.                   Same as Alternative A - Base Case.                 'Me impact on nonendangered and                     The impact on endangered and threatened
                             High Case                                                                                                                       nonthreatened marine mammals within the             marine mammals within the potentially
                                                                                                                                                             potentially affected area is expected to            affected area is expected to result in
                                                                                                                                                             result in sublethal effects that are chronic        sublethal effects that are chronic and could
                                                                                                                                                             and could result in persistent physiological        result   in   persistent physiological or
                                                                                                                                                             or behavioral changes, as well as some              behavioral changes, as well as, some degree
                                                                                                                                                             degree of avoidance of the impacted                 of avoidance of the impacted area(s).
                                                                                                                                                             areals).

                                                                                                          Same as Alternative A - Base Case.                 Same as Alternative A - Base Case.                  Same as Alternative A - Base Case.
                             Alternative 131         Same as Alternative A - Base Case.
                                                                                                          Same as Alternative A - Base Case.                 Same as Alternative A - Base Case.                  Same as Alternative A - Base Case.
                             Alternative C2          Same as Alternative A - Base Case.
                                                                                                          No effect.                                         No effect.                                          No effect.
                             Alternative D'          No effect.























                            Table S-4 Comparison and Summary of Impacts for Alternatives A-D and Cumulative in the Western Planning Area (Sale 143) (continued)

                            Alternatives                                                                                         Resource Categories




                                                                                                                                                                                                   Marine Mammals
                                                                     Water Quality                                        Air Quality                          Nonendangered and Nonthreatened                        Endangered and Threatened

                            Cumulative Impacts       Cumulative demands resulting from the               Emission of pollutants into the atmosphere         The impact on nonendangered and                    The impact on endangered and threatened
                                                     proposal are expected to result in significant      from the activities assumed for the OCS            nonthreatened marine mammals within the            marine mammals within the potentially
                                                     changes to the ambient concentration of one         program within the VVFPA are expected to           potentially affected area is expected to           affected area is expected to result in a
                                                     or more water quality parameters up to              have concentrations that would not change          result in a decline in species numbers or          decline in species numbers or temporary
                                                     several hundred to 1,000 in from the source         onshore air quality classifications. Increases     temporary displacement from their current          displacement        from     their     current
                                                     of activities and for a period lasting up to        in onshore concentrations of air pollutants        distribution, a decline or displacement that       distribution, a decline or displacement that
                                                     several weeks or months in duration.                from the High Case are estimated to be             will last more than one generation.                will last more than one generation.
                                                     Chronic pollution related to the proposal           between I and 14.5 iLgml (box model steady
                                                     will occur throughout the life of the               concentrations).    This concentration will
                                                     proposed action.         Overall cumulative         have minimal impact during winter because
                                                     impacts, which include the effects of non-          onshore winds occur only 34 percent of the
                                                     OCS-related factors and OCS activities, will        time, with maximum impact in winter when
                                                     significantly degrade water quality, primarily      onshore winds occur 85 percent of the time.
                                                     within the Gulf of Mexico's coastal zone in
                                                     highly urbanized and industrialized coastal
                                                     areas. Maritime activities will contribute to
                                                     water quality degradation near ports and
                                                     major navigation channels. In restricted or
                                                     poorly flushed coastal waterbodies, localized
                                                     increases    in    pollutant     concentration
                                                     (nutrients, organic matter, trace metals,
                                                     organotins, hydrocarbons, etc.) may be
                                                     severe and persist for months or longer.
                                                     Chronic-, Inw-leve.] pollution will mittimie. to
                                                     persist in marine and coastal waters.
















                           Table S4 Comparison and Summary of Impacts for Alternatives A-D and Cumulative in the Western Planning Area (Sale 143) (continued)
                           Alternatives                                                                                         Resource Categories

                                                                                                                                        Coastal and Marine Birds
                                                                   Marine Turtles                         Nonendangered and Nonthreatened                         Endangered and Threatened                             Commercial Fisheries
                           Alternative A           The impact on marine turtles within the             The impact on nonendangered and                   The impact on endangered and threatened            The impact on commercial fisheries within
                           Base Case               potentially affected area is expected to            nonthreatened coastal and marine birds            birds within the potentially affected area is      the potentially affected area is expected to
                                                   result in sublethal effects that are chronic        within the potentially affected area is           expected to result in no discernible decline       result in no discernible decrease in a
                                                   and could result in persistent physiological        expected to result in no discernible decline      in a population or species and no change in        population of commercial importance, its
                                                   or behavioral changes.                              in a population or species and no change in       distribution and/or abundance on a local or        essential habitat, or in commercial fisheries
                                                                                                       distribution and/or abundance on a local or       regional scale.     Individuals experiencing       on a local scale. Any affected population
                                                                                                       regional scale.    Individuals experiencing       sublethal     effects    will    recover      to   is expected to recover to predisturbance
                                                                                                       sublethal    effects    will    recover      to   predisturbance conditions in less than one         condition in one generation.
                                                                                                       predisturbance condition in less than one         generation.
                                                                                                       generation.

                           Alternative A           Same as Alternative A - Base Case.                  Same as Alternative A - Base Case.                Same as Alternative A - Base Case.                 Same as Alternative A - Base Case.
                           High Case

                           Alternative  BI         Same as Alternative A - Base Case.                  Same as Alternative A - Base Case.                Same as Alternative A - Base Case.                 Same as Alternative A - Base Case.

                           Aiternative C2          Same as Alternative A - Base Case.                  Same as Alternative A - Base Case.                Same as Alternative A - Base Case.                 Same as Alternative A - Base Case.

                           Alternative  D'         No effect.                                          No effect.                                        No effect.                                         No effect.
                           Cumulative Impacts      The impact on marine turtles within the             The cumulative effect on coastal and marine       The impact of the Cumulative Case                  The cumulative on the commercial fishing
                                                   potentially affected area is expected to            birds within the potentially affected area is     Scenario on endangered and threatened              industrywithin the potentially affected area
                                                   result in a decline in species numbers or           expected to result in a discernible decline in    birds within the potentially affected area is      is expected to result in a discernible decline
                                                   temporary displacement from their current           a local coastal or marine bird population or      expected to result in a decline in species         in populations of commercial importance,
                                                   distribution, a decline or displacement that        species, resulting in a change in distribution    number or temporary displacement from              in the quality of essential habitats, or in
                                                   will last more than one generation.                 or abundance. Recruitment will return the         their current distribution, a decline or           commercial fishing activity. Recruitment
                                                                                                       population or affected species to its pre-        displacement that will last more than one          will return any affected population, habitat,
                                                                                                       impact level and/or condition within one to       generation.                                        or activity to pre-impact level and/or
                                                                                                       two generations. It is doubtful that this                                                            condition within two to three generations.
                                                                                                       impact will affect regional populations.





















                           Table S-4 (continued) Comparison and Summary of Impacts for Alternatives A-D and Cumulative in the Western Planning Area (Sale 143)


                           Alternatives                                                                                       Resource Categories

                                                                                 Recreational Resources and Activiies                                                                       Archaeological Resources
                                                                     Beach Use                                       Marine Fishing                                       Historic                                        Prehistoric

                           Alternative A            The proposed action is expected to result in     One platform complex (2-3 structures)             There is a very small possibility of an impact    There is a very small possibility of an
                           Base Case                periodic loss of solid waste items likely to     installed as a result of this proposal within     between OCS oil and gas activities and a          impact between OCS oil and gas activities
                                                    wash up on recreational beaches, which is        30 mi of shore is expected to attract             historic shipwreck or site. Should such an        and a prehistoric site. Should such an
                                                    expected to diminish enjoyment of some           fishermen and improve fishing success in the      impact occur, unique or significant historic      impact occur, unique or significant
                                                    beach visits but is unlikely to affect the       vicinity of the platform complex for a period     archaeological information could be lost          prehistoric archaeological        information
                                                    number or type of visits currently occurring     of about 20 years.                                                                                  could be lost.
                                                    on Texas beaches.


                           Alternative A            Same as Alternative A - Base Case.               Same as Alternative A - Base Case.                Same as Alternative A - Base Case.                Same as Alternative A - Base Case.
                           High Case


                           Alternative BI           Same as Alternative A - Base Case.               Same as Alternative A - Base Case.                Same as Alternative A - Base Case.                Same as Alternative A - Base Case.

                           Alternative C2           Same as Alternative A - Base Case.               Same as Alternative A - Base Case.                Same as Alternative A - Base Case.                Same as Alternative A - Base Case.


                           Alternative W            No effect.                                       No effect.                                        No effect.                                        No effect.

                           Cumulative Impacts       Although trash and accidental oil spills will    Continued offshore oil and gas development        The total ofOCS program and nonprogram-           The    total of OCS          program and
                                                    continue to affect the ambience of Texas         over the next 35 years will continue to           related impact-ptoducing factors have likely      nonprogram-rclated         impact-producing
                                                    recreational beaches, the level of chronic       support, maintain, and facilitate offshore        resulted in loss and may yet result in loss of    factors have likely resulted in loss and may
                                                    pollution should decline during the life of      recreational fishing in the WPA and extend        significant or unique historic archaeological     yet result in loss of significant or unique
                                                    the proposed action.      Beach use at the       the time offshore oil and gas production          information.                                      prehistoric archaeological information.
                                                    regional level is unlikely to change; however,   structures are a focus of offshore fishing
                                                    closure of specific beaches or parks directly    activity.
                                                    impacted by one or two oil spills greater
                                                    than or equal to 1,000 bbi is likely during
                                                    cleanup operations.

















                        Table S-4 Comparison and Summary of Impacts for Alternatives A-D and Cumulative in the Western Planning Area (Sale 143) (continued)

                        Alternatives                                                                                           Resource Categories

                                                                                                                                        Socioeconomic Conditions

                                                               Population, Ubor, and Employment                                   Publk Services and Infrastructure                                              Social Patterns
                        Alternative A             The impact in the Western Guffon the population, labor, and            Population and employment impacts will not result            It is expected that no net migration will occur as a result of the
                        Base Case                 employment of the counties and parishes of the Central and             in disruptions to community infrastructure and               proposed action. Deleterious impacts to social patterns are
                                                  Western Gulf Coastal impact area is expected to be less than           public services beyond what is anticipated by in-            expected to occur in some individual cases as a result of
                                                  I percent of the levels expected in the absence of the                 place planning and development agencies.                     extended work schedules, displacement from traditional
                                                  proposal.                                                                                                                           occupations, and relative wages.
                        Alternative A             Same as Alternative A - Base Case.                                     Same as Alternative A - Base Case.                           Same as Alternative A - Base Case.
                        High Case


                        Alternative BI            Same as Alternative A - Base Case.                                     Same as Alternative A - Base Case.                           Same as Alternative A - Base Case.

                        Alternative C'            Same as Alternative A - Base Case.                                     Same as Alternative A - Base Case.                           Same as Alternative A - Base Case.

                        Alternative D3            No effect.                                                             No effect.                                                   No effect.
                        Cumulative Impacts        The impact from prior sales, the proposed actions, and future          The impact on public services and community                  Under the cumulative scenario, it is expected that some loss of
                                                  sales on the population, labor, and employment of the                  infrastructure is not expected to result in long-term        traditional occupations will occur.        Deleterious impacts to
                                                  counties and of the coastal impact area is significant,                (greater than 3 years) disruptions in delivery of            cultural heritage and family life are also expected to occur in
                                                  amounting to approximately 277,300 person-years of                     public services or maintenance of community                  some individual cases.
                                                  employment over the life of the proposed action.                       infrastructure because of the diversified local
                                                  Employment needs in support of OCS oil and gas activity are            economy and the small percentage of impact of the
                                                  likely to be met with the existing population and available            OCS     program      on    local    employers       and
                                                  labor force.                                                           demographies.



                        'Alternative B - The Proposed Action Excluding the Blocks Near Biologically Sensitive Topographic Features
                        2A]ternative C - The Proposed Action Excluding the Western Naval Operations Area
                        .'Alternative D - No Action







    THE PROPOSED ACTIONS


    ALTERNATIVES INCLUDING
    THE PROPOSED ACTIONS


    DESCRIPTION OF THE
    AFFECTED ENVIRONMENT

    ENVIRONMENTAL
    CONSEQUENCES
    CONSULTATION AND             v
    COORDINATION

    BIBLIOGRAPHY AND
    SPECIAL REFERENCES           V-L

    PREPARERS
    GLOSSARY                    vii,

    APPENDICES








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  1-11



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   SECTION I
   THE PROPOSED ACTIONS           I












                                                                                                                             1-3

              1. THE PROPOSED ACTIONS

              A. PURPOSE, NEED, AND DESCRIPTION

                  The purpose of the two proposed Federal actions addressed in this Environmental Impact Statement (EIS)
              is the offering for lease of areas on the Central and Western Gulf of Mexico Outer Continental Shelf (OCS)
              for the exploration and development of recoverable oil and gas resources. The Department of the Interior
              (DOI) is required, under the Outer Continental Shelf Lands Act (OCSLA), as amended, to manage the leasing,
              exploration, development, and production of oil and gas resources on the OCS. The Secretary of the Interior
              (Secretary) oversees the OCS off and gas program and is required to balance orderly resource development
              with protection of the human, marine, and coastal environments while simultaneously ensuring that the public
              receives an equitable return for these resources and that free-market competition is maintained.
                  The proposed sales are part of DOI's proposed 5-Year Program, which covers the period from mid-1992
              to mid-1997. The proposed sales are scheduled to occur in 1993. The sale areas are depicted in Figure I-1
              and lease blocks and lease status are shown on Visual No. 1. The East and West Flower Garden Banks
              deferral areas shown on Figure 1-1 are not drawn to scale and are not as large as they appear. In addition,
              it should be pointed out that some areas adjacent to the two blocks containing the Flower Garden Banks are
              also included in the area not offered under Alternative B. Nearly 9,900 blocks will be available for lease under
              the two proposed actions, but only a small percentage are expected to actually be leased. The average number
              of blocks leased in individual Gulf of Mexico OCS lease sales since 1984 have been 434 (8 sales) in the Central
              Gulf and 264 (8 sales) in the Western Gulf.
                  The following are brief descriptions of the proposed actions, alternatives, and mitigating measures. Also
              provided are assumptions and estimates of the amounts, locations, and timing for OCS exploration,
              development, and production operations that are used in the analysis of potential impacts from the proposed
              actions (Base Case). More detail is available elsewhere in the document (alternatives, Sections I.B.2.a. and
              II.A. and B.; potential mitigating measures, Sections I.B.2.b., II.A-l.c., and II.B.I.c; and the proposed actions
              scenario description, Section IV.A-).
                  Proposed Central Gulf Sale 142 is scheduled to be held in March 1993 and will offer approximately 5,194
              unleased blocks (as of January 1992), comprising about 28.0 million acres in the Central Planning Area (CPA).
              This area includes acreage located from 4.8 to 354 kilometers (km) offshore in water depths ranging from 4
              to 3,425 meters (m). The alternatives are to delete all unleased blocks of the 167 total blocks on or near
              biologically sensitive areas of the topographic features or to take no action (cancel the sale). The following
              are assumptions regarding amounts and timing of activities that will result from proposed sale 142 (Base Case):

                       -   During the exploration phase, 1994-2004, 340 wells will be drilled.

                       -   During the development phase, 1995-2017, 130 oil wells and 120 gas wells will be drilled and
                           30 platform complexes will be installed.

                       -   During the production phase, 1995-2026, 0.140 billion bbl of oil (BBO) and 1.40 trillion cubic
                           feet (tco of gas will be produced.

                       -   By the end of 2027, all platforms associated with the proposed action will be removed, with
                           20 structures being removed explosively, and the remaining 10 being removed by nonexplosive
                           methods.


                          The transportation of this oil and gas will require the following:

                               the construction of 240 km of gathering pipelines, which will be connected to
                               existing trunklines prior to landfall (at offshore locations);









                                                                                                                                                                                                      M

                                                                                                                                                                                                   Gulf
                                                                                                                     LOUISIANA
                                                    TEXAS                                                                                                                  NeW.
                                                                                                                                                                           Orleqn,'.-
                                                                            Houston






                                                                                            Galveston


                                                                                                                                                                                            Sat"
                                                                                                                                         *Sonni*r
                                                                                                   Stetson                                    Ald-,rdl- OFIShnat  Ejlng   Diaphus
                                                                                      32 Fathom*                         9 F,fh,.Mc
                                                                                                        L. .' *MOCN.il0           Grail  0 Rezak           kkul
                                                              B(q   Small Dunn Ear                      Eas'(;F'rQd'.tr                           0 Parker
                                                                                           Appelbaum
                                                                                                       Flo    and., rk                                   S.-t
                             Corpu@                       Bok-ik S. Baker                                wer Forden,             Elvors
                             Christi
                                                             Aro


                                                      southern
                                                                                  WESTERN PLANNING                                         AREA CENTRAL PLANNI


                                                     0 Blackfish
                                                         My.1.'ro.8                                                                                                      Location of Topographi
                                                                            0     Location of Topographic Features Areas                                                 Not offered under Alte
                                                                                  Not offered under Alternative 6
                                                                                  Area not offered under Alternative C
                                                                            0     Deferred (East and West Flower Carden Banks)





                            Figure 1-1. Central and Western Gulf Planning Areas, Indicating Deferred Areas and Areas Affected b









                             77 barge trips carrying oil to eight existing shore terminals along the Texas and Louisiana
                             coasts; and

                             2 shuttle tanker trips carrying oil to Mississippi River terminals.
                             No new onshore support or processing facility construction is expected; existing
                             OCS-related facilities will be utilized.

                             Major offshore transport of personnel and supplies will involve 368,000 helicopter trips
                             and 17,600 service vessel trips.

                             Potential accidents include the following:

                             -  four blowouts (Section IV.A.2.d.(8)); and
                             -  one large offshore spill of 6,500 barrels (bbl) with a 2 percent probability of
                                contacting land within 10 days; a few offshore spills between 50 and 1,000 bbl;
                                and several spills greater than 1 bbl but less than 50 bbl occurring from both
                                onshore and offshore operations.
                   Section IV.A_ fully describes activities and impact-producing factors assumed to occur from proposed Sale
               142.
                   Proposed Western Gulf Sale 143 is scheduled to be held in August 1993 and will offer approximately 4,715
               unleased blocks (as of January 1992), comprising about 25.8 million acres in the Western Planning Area
               (WPA). This area is located from 14 to 357 km offshore in water depths ranging from 8 to over 3,000 m.
                   Blocks A-375 (East Flower Garden Bank) and A-398 (West Flower Garden Bank) in High Island Area,
               East Addition, South Extension, were deferred (or excluded) from this proposed action because of the
               environmentally sensitive nature of the biological communities located in the blocks. The alternatives are to
               delete all unleased blocks of the 200 total blocks on or near biologically sensitive areas of the topographic
               features, to delete approximately 340 blocks (about 1.8 million acres) contained in the Western Naval
               Operating Area near Corpus Christi, Texas, or to take no action (cancel the sale). The following are
               assumptions regarding the amounts and timing of activities that will result from proposed Sale 143 (Base Case):
                        -    During the exploration phase, 1994-2004, 210 wells will be drilled.

                        -    During the development phase, 1995-2017, 50 oil wells and 60 gas wells will be drilled and 10
                             platform complexes will be installed.

                        -    During the production phase, 1995-2026, 0.05 BBO and 0.74 tcf of gas will be produced.
                        -    By the end of 2027, all platforms associated with the proposed action will be removed, with
                             six being removed explosively, and the remaining four being removed by nonexplosive
                             methods.

                        -    The transportation of gas and oil will require the following:

                             - the construction of 80 km of gathering pipelines, which will be connected to
                               existing trunklines prior to landfall (at offshore locations);
                             - 9 barge trips carrying oil to three existing shore terminals along the Texas
                               and Louisiana coasts; and










                   1-6
                                -   66 shuttle tanker trips carrying oil to both Texas and LA)uisiana terminals.
                           -    No new major onshore support or processing facility construction is expected; existing
                                OCS-related facilities will be utilized.
                           -    Major offshore transport of personnel and supplies Will involve 131,000 helicopter trips and
                                6,600 service vessel trips.

                          -     Potential accidents include the following:

                                -   two blowouts (Section IV.A_2.d.(8)); and
                                -   several spills greater than 1 bbl less than 50 bbI occurring both onshore and
                                    offshore.
                       Section W.A. fully describes activities and impact-producing factors assumed to occur from proposed Sale
                   143.
                       In addition to the alternatives that are options for each proposed lease sale, there are a number of
                   statutory requirements, regulations, and procedures in place that are designed to avoid environmental/safety-
                   related problems. These requirements, regulations, and procedures have evolved over the 35 + years of leasing
                   for oil and gas on the OCS. The following are examples of some of the most important ofthese measures.
                       Exploration Plans (EP's) must be submitted and approved by the Minerals Management Service (MMS)
                   before an operator can begin exploratory drilling on any OCS lease. Development and production activities
                   require a Development Operations Coordination Document (DOCD) as described later. Both types of plans
                   must include supporting information providing an analysis of onshore and offshore impacts that may occur as
                   a result of implementation of the plan. Based on this and other available information, MMS prepares either
                   a Categorical Exclusion Review (CER), an Environmental Assessment (EA), and/or an EIS. Plans must also
                   include a certification of consistency with the approved Coastal Zone Management (CZM) program of the
                   affected State (the only Gulf Coast state that does not have such a program is Texas). The certification. assures
                   that the activities described in the plan will be conducted in a manner consistent with the program. More
                   information on the requirements of these plans is available in Sections I.13.3.d.(1)(a) and (b).
                       Oil Spill Contingency Plans (OSCP) must be submitted by an operator for approval with, or prior to, an
                   EP or a DOCD. This contingency plan, outlining the availability of spill containment and cleanup equipment
                   and trained personnel, is reviewed and updated annually. The OSCP must assure that full-response capability
                   could be committed during an oil-spill emergency. This commitment would include specifications for
                   appropriate equipment and materials, their availability, and the time needed for deployment. The OSCP also
                   must include provisions for varying degrees of response effort, depending on the severity of the spill. See
                   Sections I.B.3.d.(1)(c) and IV.C.5. for more information.
                       Inspections are conducted by MMS, in accordance with the OCSLA, before, during, and after operations
                   to assure that safety and pollution-prevention requirements are met. Inspections are to include all safety
                   equipment designed to prevent or ameliorate blowouts, fires, spillage, or other major accidents. Inspections
                   assure that the best available and safest technology (BAST) is used for operations and procedures that, if failed,
                   could have a significant effect on safety, health, or the environment. See Sections I.B.3.d.(2'Ka) and
                   I.13.3.d.(3)(a) for more information on inspections and BAST.
                       Training of oil-field personnel is another important factor in ensuring that OCS operations are carried out
                   in a manner that emphasizes safety and minimizes the risk of environmental damage. Everyone directly
                   concerned with the actual drilling of a well is required to have passed a course in well control at an MMS
                   approved school. In addition, all operators must have trained personnel to operate oil-spill cleanup equipment
                   or must have retained a trained contractor to operate the equipment for them. Additional training
                   requirements exist for workovers, completions, and production operations. For more information see Section
                   1.13.3.d.(3)(d).










                                                                                                                              1-7

               &BACKGROUND

               1. Administrative Events Leading to the Proposed Actions

                   On June 13, 1991, the Call for Information and Nominations (Call) and the Notice of Intent to Prepare
               an EIS (NOI) for the 1993 lease sales were published in the Federal Register. Federal, State, and local
               governments, along with other interested parties, were requested to send written comments to the Region on
               the scope of the EIS, on significant issues that should be addressed, and on alternatives and mitigating
               measures that should be considered. Sending the Call/NOI to individuals, environmental groups, and industry,
               along with Federal, State, and local governments, provides those individuals with an interest in the OCS
               program an early opportunity to participate in the events leading to the publication of the Draft EIS.
                   Even though the Call and NOI formally initiate the scoping process for the EIS, scoping efforts and other
               coordination meetings were also conducted prior to publication of the Call and NOI in the Federal Register.
                   In April 1991, a Regional Technical Working Group (RTWG) meeting was held to discuss a variety of
               OCS-related matters, including the status of the draft EIS's in preparation at the time. A meeting held under
               the provisions of Section 655 of the Departmental Manual (DM 655) was convened on November 15, 1990,
               to discuss a wide variety of matters, including visual representation of environmental data, stipulations, and
               other mitigating measures. Relevant comments and information from these meetings are incorporated into the
               Draft EIS.
                   The OCSLA requires that DOI prepare a 5-year program that specifies, as precisely as possible, the size,
               timing, and location of areas to be assessed for Federal offshore natural gas and oil leasing. The new program,
               referred to as the Comprehensive Outer Continental Shelf Natural Gas and Oil Resource Management P@ogram,
               1992-1997, is now in the draft stage and is scheduled for completion in mid-1992. A new Area Evaluation and
               Decision Process (AEDP) for the consideration of leasing has been included which, among many other features,
               heightens attention to the adequacy of information for decisionmaking. In the Gulf of Mexico, the first
               proposed OCS lease sales that would be planned and analyzed in accordance with this new proposed process
               include proposed Sales 142 and 143. The July 1991 announcement of the Proposed Comprehensive Program
               for 1992-1997 included a description of the AEDP. Under the AEDP, the area proposed for leasing and the
               stipulations that are included in the analysis of the proposed action will be included in the notice of sale that
               will be made available concurrently with this Draft EIS.
                   The first step of the new AEDP is called the Information Base Review. The Information Base Review is
               a formal documented MMS assessment of the status of and plans regarding additions to the information base
               for potential decisions on a leasing proposal that acknowledges the concerns of other interested parties. This
               assessment can be used as a guide to subsequent planning and consultation efforts for the development of a
               specific leasing proposal and as an indication of the focus and timing of future studies and analytical efforts.
               This review covers environmental, geologic, and operational information.
                   The Information Base Review, completed in May 1991, consisted of three principal steps: (a) a two-day
               comprehensive review of available environmental information and proposed new environmental studies was
               held at the Gulf of Mexico RTWG meeting on April 2-3, 1991; (b) an internal review of available data and
               planned studies was conducted by the Gulf Region to obtain a comprehensive assessment of the status of the
               information base; and (c) letters were sent to various interested parties, which included RTWG members,
               Coastal Zone Management offices, State government representatives, and environmental groups, to solicit their
               participation in the Information Base Review process. Personal contacts with interested parties were also made
               by MMS, Gulf of Mexico Region personnel.
                   On May 30, 1991, a scoping workshop was held in Mobile, Alabama; this followed a public hearing on the
               Draft EIS for Sales 139 and 141. Notice of this scoping workshop was included in approximately 800 notices
               that were mailed out for the public hearing. In addition, approximately 150 separate notices regarding the
               scoping workshop were distributed to interested parties in the Alabama and Mississippi coastal areas.
               However, only three individuals attended the workshop- two from the Louisiana Department of Natural
               Resources in Baton Rouge, Louisiana, and one from Shell Oil Company in New Orleans, Louisiana. Topics
               discussed included normally occurring radioactive materials (NORM), CZM issues, onshore disposal of waste











                   1-8

                   generated by OCS activities, and whether existing navigation channels would have to be enla:rged to
                   accommodate passage of larger structures as oil and gas activities move into deeper offshcre waters.
                   2. Scoping Activities and Findings

                       Scoping is the process by which issues related to the proposed actions are identified. A scoping effort was
                   conducted for this EIS to provide additional information for the development of appropriate alternatives and
                   mitigating measures, as well as to identify significant issues. The governors of the Gulf States; Federal, State,
                   and local agencies; industry-, environmental groups; and interested individuals were given an opportunity to
                   comment. Section V contains a detailed description of this consultation and coordination process. The result
                   of the scoping effort was the selection of the alternatives, mitigating measures, and issues described below.

                   a. Alternatives

                   (1) Alternatives for Proposed Central Gulf Sale 142

                       Alternative A (77te Proposed Action): The proposed action for Sale 142 is to offer for lease all unleased
                   blocks, approximately 28.0 million acres, or a maximum of 5,194 blocks (as of January 199Q), within the CPA
                   for oil and gas operations. Acreage and block counts are subject to change as a result of ongoing activity.
                       Alternative B (The ProposedAction Excluding the Blocks Near Biologically Sensitive Topographic Features):
                   This alternative would delete all unleased blocks within a total of 167 blocks potentially affected. by the
                   Topographic Features Stipulation and offer for lease an remaining blocks.
                       Alternative C (No Action): This alternative is equivalent to cancellation of a sale scheduled for a specific
                   timeframe on an approved 5-year OCS Oil & Gas Leasing Schedule. The opportunity for development of the
                   estimated oil and gas resources that could have resulted from this sale is foregone or postponed, and any
                   potential environmental impacts resulting from the proposed action would not occur or would be postponed.

                   (2) Alternatives for Proposed Western Gulf Sale 143

                       Alternative A (7he Proposed Action): The proposed action for Sale 143 is to offer for lease all unleased
                   blocks, except 2, within the WPA for oil and gas operations. This totals approximately 25.8 million acres or
                   4,715 blocks as of January 1992. The exceptions are Blocks A-375 and A-398 in High Island Area, East
                   Addition, South Extension (East and West Flower Garden Banks, respectively). The deferral of the two Flower
                   Garden blocks were established in the Area Identification for the proposed sales. Acreage and block counts
                   to be offered for lease are subject to change as a result of ongoing activity.
                       Alternative B (The Proposed Action Excluding the Blocks Near Biologically Sensitive Topographic Features):
                   This alternative would delete all unleased blocks within a total of 200 blocks potentially affected by the
                   Topographic Features Stipulation and lease all remaining blocks.
                       Altemative C (7he Proposed ActionErcluding Blocks Contained in the Western Naval OperationsArea): This
                   alternative would delete approximately 340 blocks contained in the Western Naval Operations Area near
                   Corpus Christi, Texas.
                       Alternative D (No Action): This alternative is equivalent to cancellation of a sale scheduled for a specific
                   timeframe. The opportunity for development of the estimated oil and gas resources that could have resulted
                   from proposed Sale 143 would be precluded or postponed. Also, any potential environmentil impacts iresulting
                   from the proposed action would not occur or would be postponed.

                   (3) Alternatives Considered But Not Offered

                       Delete Live-bottom Areas (Pinnacle Trend): This alternative would delete the pinnacle trend area, a region
                   of topographic features in the northeastern corner of the CPA- The blocks in this portion ofthe planning area,












                                                                                                                             1-9

               which contain topographic features and/or dense biological communities that warrant protection, are not yet
               fully defined. Ongoing studies will more accurately delimit these features and communities. Any of these
               blocks, which may be leased as a result of the proposed action, may contain a lease stipulation, at the
               Secretary's discretion, designed to provide adequate protection to the benthic biota of the area. Removal of
               these blocks is not necessary for their protection at this time.
                   Limit the Amount of LWIling with Substitution of Alternative Energ to Meet National Energ Needs: This
               alternative would provide for replacement of 20, 40, 60, and 80 percent of the oil and gas from the Gulf of
               Mexico with energy from alternative sources. Appendix C of the Draft EIS for the Comprehensive Program
               for 1992-1997 includes a comparative environmental analysis of energy alternatives to OCS oil and gas (USDOI,
               MMS, 1991a), and this analysis is also included in Appendix D of this EIS.

               b. Mitigating Measures

               (1) Potential Mitigating Measures Analyzed in the EIS

                   The potential mitigating measures included for analyses in this EIS were developed as the result of the
               scoping efforts accomplished early in the EIS process and over recent years for the continuing OCS
               program.
                   Four stipulations that have been applied to appropriate Gulf OCS leases for many years with considerable
               success have been included for analysis for proposed lease Sales 142 and 143. These are the Live Bottom
               (Pinnacle Trend), Topographic Features, Archaeological Resource, and Military Areas Stipulations for the
               Central Gulf sale; and the Topographic Features, Archaeological Resource, and Military Areas Stipulations
               for the Western Gulf sale. The effectiveness of the proposed stipulations is discussed in Section II. The
               analysis of these stipulations as proposed mitigating measures does not preclude a decision by the Secretary
               not to apply the stipulations to leases that may result from the proposed actions nor does it preclude minor
               modifications in wording during subsequentsteps in the sale process if comments indicate changes are necessary
               or if conditions change.

               Live Bottom Stipulation

                   The Live Bottom Stipulation included for analysis in proposed Sale 142 covers the pinnacle trend area of
               the CPA. The northeastern portion of the Central Gulf contains a band of pinnacles between 67 and 109 in
               (220-360 ft) in depth, which extends into the northwestern portion of the Eastern Gulf. The pinnacles appear
               to be dead reefal structures with limited biotal coverage, but they may provide structural habitat for a variety
               of pelagic fish. A Live Bottom Stipulation has been made a part of previously issued leases and is a part of
               many active leases in the Central Gulf. This stipulation has been deemed necessary in the past since the
               position and "tent of many of the sensitive and high-value, live-bottom areas were poorly known. These areas
               are, for the most part, patchy and scattered. A discussion of the effectiveness of this proposed stipulation is
               in Section Il.


               Topographic Features Stipulation

                   The topographic features of the Central and Western Gulf provide habitat for coral and coral-community
               organisms. These communities would be severely and adversely impacted if unrestricted oil and gas activities
               resulting from the proposed actions took place on, or in proximity to, them. The Department has recognized
               this problem for some years and, since 1973, topographic features stipulations have been made a part of leases
               for blocks on or near these biotic communities. The proposed Topographic Features Stipulation--developed
               through close consultation and coordination between various State, Federal, and local agencies--uses the results
               of the latest topographic-features studies and industry monitoring reports, and may be made, at the Secretary's
               discretion, a part of appropriate leases resulting from proposed Sales 142 and 143. A discussion of the
               effectiveness of this proposed stipulation is in Section 11.











                  1-10


                  Archaeological Resource Stipulation
                       This proposed stipulation was first implemented in 1973 in response to the requirements of the National
                  Historic Preservation Act of 1966, as amended. In addition, the OCSLA, as amended, specifically states in
                  Section 11(g)(3) that such exploration (oil and gas) will not ". . . disturb any site, structure, or object of
                  historical or archaeological significance." Therefore, this stipulation may be made a part of leases resulting
                  from proposed Sales 142 and 143. The proposed stipulation includes a clause that requires an archaeological
                  assessment of geophysical survey data within areas where the Regional Director has a reason to believe that
                  an archaeological resource is likely to exist. Archaeological management zones derived from the findings of
                  the Gulf of Mexico cultural resources baseline study (CEI, 1977), as well as a more recent study of shipwrecks
                  in the northern Gulf of Mexico (Garrison et al., 1989). The zones of prehistoric and historic high probability
                  are used as the basis for invoking the archaeological survey requirement. Most tracts leased within the refined
                  high probability zone for historic shipwrecks, where there is a high potential for the occurrence of historic sites,
                  require a survey of 150-in linespacing. Those tracts that have a high probability for historic shipwrecks and
                  are defined as occurring in water depths greater than 60 in require archaeological analysis based on standard
                  shallow hazard survey parameters with 300-in linespacing. Tracts leased within Zone 2, where there is only
                  the potential for the occurrence of prehistoric sites, require a survey of 300-m linespacing. The requirements
                  for the archaeological survey and report are detailed in Notice to Lessees and Operators (NTL) 92-01
                  (Appendix E). The proposed archaeological stipulation may reduce the potential impacts to proposed
                  archaeological sites from oil and gas development by allowing detection of potential sites prior to development,
                  thereby making avoidance possible.

                  Milita?y Areas Stipulations
                       A standard Military Areas Stipulation has been applied to all blocks leased in military areas in the Gulf
                  of Mexico since 1977. One of the requirements of the proposed stipulation is that the operator would notify
                  the military prior to conducting oil and gas activities in an area. The effectiveness of the stipulation may be
                  illustrated by the fact that there have been no reported accidents in the Gulf resulting from. conflicts between
                  oil and gas operations and military activities. Therefore, this stipulation may be made, at the Secretary's
                  discretion, a part of leases resulting from both proposed Sales 142 and 143. A discussion of the effectiveness
                  of this stipulation is in Section Il.

                  (2) Mitigating Measures Considered But Not Analyzed

                       Five potential mitigating measures were considered for possible analysis in this EIS, but subsequently
                  rejected from further discussion. These measures are described below, along with the reasons for not offering
                  them as potential mitigation.
                       Oil-Spill Response Stipulation (or regulations): The development of an oil-spill response stipulation for the
                  Central and Western Gulf of Mexico, similar to those in place for portions of the Eastern Planning Area
                  (EPA), was proposed by the Sierra Club in response to the Draft EIS for Sales 139 and 14-1. The protection
                  afforded by such a stipulation can be achieved through the oil-spill response equipment sharing effort currently
                  being required. This equipment sharing effort results in suitably equipped vessels being strategically sited at
                  offshore locations throughoutthe Gulf of Mexico. The number of rig/platform sites in proximity to one another
                  makes a spill-response equipment sharing approach practicable while also providing the necessary benefits of
                  significantly reduced spill-response times. Working with industry through the existing regulatory framework
                  allows greater flexibility in updating equipment siting as warranted through the review of ofl-spill contingency
                  plans, ongoing research, or recommendations made as a result of the unannounced oil-spill response drilling
                  program.
                       Add Sebree, Big Adam, Little Adam, and Phleger Banks to the List of Banks Covered by the Topographic
                  Features Stipulation: The National Oceanic and Atmospheric Administration (NOAA) recommended that
                  Sebree Bank (off south Texas) be afforded the protection of either the Topographic Features Stipulation or











                                                                                                                                   1-11


                the Live Bottom Stipulation. Sebree Bank contains no biological assemblages requiring the protection of a
                restrictive stipulation. It is a low-relief, biologically depauperate bank with sparse occurrences of Oculina
                diffusa in a muddy, turbid environment. The area of Sebree Bank should not be subjected to either of these
                biological stipulations. For similar reasons, the other three banks have never been considered for the
                protection of the stipulation and are not candidates for such protection at this time.
                     Stipulation to Protect Chemosynthetic Biological Communities: The NOAA recommended that a
                chemosynthetic community stipulation similar to NTL 88-11 be adopted. Adequate and appropriate protection
                is afforded the chemosynthetic communities by NTL 88-11. The NTL is applied and enforced on all leases,
                existing or future, which potentially contain chemosynthetic communities. A stipulation would apply only to
                any future leases to which the stipulation may be attached. Incorporation of similar requirements into a lease
                stipulation would be redundant.
                     Prohibit All Discharges ftom OCS Facilities: The Delta Chapter of the Sierra Club requested that all
                discharges from OCS facilities be prohibited. Discharges from OCS facilities are governed through the National
                Pollution Discharge Elimination System (NPDES) administered by the U.S. Environmental Protection Agency
                (USEPA). The USEPA is establishing effluent limitations for operational discharges from OCS oil and gas
                exploration, development, and production activities. These limitations, as well as monitoring and other
                requirements, will be included in two general NPDES permits covering all Gulf OCS oil and gas operations.
                Prior to the issuance of the permit, public comments are being solicited and will be considered for
                incorporation into the permit requirements. These permit and effluent limitations will assure that there is no
                significant degradation of regional water quality characteristics.
                     Require Altemative Procedures to Fxplosive Structure Removal: The Sierra Club (Houston Regional Group)
                and the Office of the Attorney General (State of Texas) have recommended that MMS require alternative
                methods to explosive structure removal. The most effective methods of structure removal are the use of
                explosives and underwater arc cutting. Some operators have used nonexplosive removal methods where
                feasible. During 1990, approximately 19 percent of all structure removals were accomplished by nonexplosive
                techniques. The feasibility of using these techniques is largely dependent upon the type of structure as well
                as the individual design. More perfection of nonexplosive structure removal techniques is needed before a
                universal requirement is imposed.

                c. Issues


                (1) Significant Issues

                     Issues are defined by the Council of Environmental Quality (CEQ) to represent those principal "effects"
                that the EIS should evaluate in-depth. The CEQ is clear that scoping should identify specific environmental
                resources or activities, rather than identify "causes" as significant issues (CEQ Guidance on Scoping, April 30,
                1981). The analysis can then show the degree of change from present conditions for each issue due to the
                relevant actions related to the proposal.
                     Selection of environmental and socioeconomic issues to be analyzed was based on the following criteria:

                          -   The resource/activity was identified through the scoping process or from comments on a
                              draft EIS;

                          -   The resource/activity must be vulnerable to one or more of the impact-producing factors
                              (IPF) associated with. the OCS program. A reasonable probability of an interaction
                              between the resource/activity and IPF should exist; or

                          -   New information has become available that indicates a need to reevaluate the potential
                              impacts to a resource/activity.











                  1-12

                      The following resource topics have been determined to be significant environmental issues and are analyzed
                  in Section IV.D. For a list of specific resources analyzed under each proposed sale, see Table S-2.

                               Air Quality                           Live Bottoms (Pinnacle Trend)

                               Alabama, Choctawatchee,               Marine Mammals
                                and Perdido Key Beach Mice
                                                                     Marine Turtles
                               Archaeological Resources
                                                                     Recreational Resources and
                               Coastal Barrier Beaches                Activities


                               Coastal and Marine Birds              Socioeconomic Issues


                               Commercial Fisheries                  Topographic Features

                               Deep-water Benthic                    Water Quality
                                Communities
                                                                     Wetlands
                               Gulf Sturgeon

                  (2) Issues Considered But Not Analyzed

                      The following issue was raised during the scoping process but was determined not to warrant further
                  analysis in the EIS as explained below.
                      Designated environmental preservation areas were considered for analysis, but it has been determined that
                  they do not constitute an environmental issue, which requires a separate analysis in the EIS. In the past, the
                  National Park Service (NPS) has expressed concern over MMS' apparent lack of acknowledgement of the
                  nationally-recognized conservation values of the Gulf Island National Seashore, in particular, the wilderness
                  designation areas of the Seashore. The Sierra Club has asked for special protection for the Shoalwater Bay
                  area in Louisiana. In comments on the latest draft EIS, the Houston Regional Group of the Sierra Club
                  emphasized the need for designated environmental preservation areas to be considered a significant issue. The
                  MMS focuses the recreational analysis of OCS lease sale impacts on shoreftont beaches, which includes
                  national, State, or local park and recreational areas, as well as State and Federal wildlife areas. Nationally-
                  recognized values such as the National Seashore and National Wilderness Areas are amounted for under this
                  analysis.
                  3. Regulatory and Administrative Framework

                  a. Outer Continental Shelf Lands Act

                      The OCSLA of 1953 (67 Stat 462), as amended (43 U.S.C. 1331 et seq. (1988)) established Federal
                  jurisdiction over submerged lands on the OCS seaward of State boundaries (generally 3 geographic miles
                  seaward of the coastline). Under the OCSLA, the Secretary of the Interior is responsible for the administration
                  of mineral exploration and development of the OCS. The Act empowers the Secretary to grant leases to the
                  highest qualified responsible bidder(s) on the basis of sealed competitive bids and to formulate such regulations
                  as necessary to carry out the provisions of the Act.
                      The Act, as amended, provides guidelines for implementing an OCS oil and gas exploration and
                  development program. The basic goals of the Act include the following:











                                                                                                                              1-13

                       (1)    to establish policies and procedures for managing the oil and natural gas resources of
                              the Outer Continental Shelf that are intended to result in expedited exploration and
                              development of the OCS in order to achieve national economic and energy policy goals,
                              assure national security, reduce dependence on foreign sources, and maintain a
                              favorable balance of payments in world trade;

                       (2)    to preserve, protect, and develop oil and natural gas resources of the Outer Continental
                              Shelf in a manner that is consistent with the need

 4k                           (a)    to make such resources available to meet the nation's energy needs as
                                     rapidly as possible;

                              (b)    to balance orderly resource development with protection of the human,
                                     marine, and coastal environments;

                              (c)    to ensure the public a fair and equitable return on the resources of the
                                     Outer Continental Shelf-, and

                              (d)    to preserve and maintain free enterprise competition; and

                       (3)    to encourage development of new and improved technology for energy resource
                              production, which will eliminate or minimize risk of damage to the human, marine, and
                              coastal environments.

                   The Secretary of the Interior has designated MMS as the administrative agency responsible for the mineral
              leasing of submerged OCS lands and for the supervision of offshore operations after lease issuance.
              Regulations administered by MMS govern the leasing of oil, gas, and sulphur mineral deposits on the OCS (30
              CFR Z56); the conduct of mineral operations is contained in 30 CFR 250 and 30 CFR 251. Pertinent
              regulations are also found at 30 CFR 252, 259, 260, and 270.

              b. National Environmental Policy Act

                   The purpose of the National Environmental Policy Act (NEPA) of 1969 is to provide a national policy that
              encourages "productive and enjoyable harmony between man and his environment; to promote efforts which
              will prevent or eliminate damage to the environment and biosphere and stimulate the health and welfare of
              man . . . " (42 U.S.C. 4371 et seq.). The NEPA requires that all Federal agencies shall use a systematic,
              interdisciplinary approach to protection of the human environment; this approach will ensure the integrated
              use of the natural and social sciences in any planning and decisionmaking that may have an impact upon the
              environment. The NEPA also requires the preparation of a detailed EIS on any major Federal action that may
              have a significant impact on the environment. This EIS must include any adverse environmental effects that
              cannot be avoided or mitigated, alternatives to the proposed action, the relationship between short-term uses
              and long-term productivity of the environment, and any irreversible and irretrievable commitments of resources
              involved in the project.      In 1979, CEQ published regulations that established uniform guidelines for
              implementing the procedural provisions of NEPA_ These regulations (40 CFR 1500-1508, revised July 1, 1980)
              provide for the use of the NEPA process to identify and assess the reasonable alternatives to proposed actions
              that avoid or minimize adverse effects of these actions upon the quality of the human environment.                A
              procedure known as "scoping" is used to identify the scope and significance of important environmental issues
              associated with a proposed Federal action through coordination with Federal, State, and local agencies; the
              public; and any interested individual or organization prior to the development of an impact statement (40 CFR
              1501.7). The process is also intended to identify and eliminate, from further detailed study, issues that are not
              significant or that have been covered by prior environmental review.











                    1-14


                    c. Presale Activities


                    (1) FederallState Coordination

                        In addition to scoping activities conducted with the public and other Federal agencies, as described in the
                    scoping section above and in Section I.B.3.b., the OCSLA provides a statutory foundation for DOI's policy of
                    coordination with the affected States and, to a more limited extent, local governments. At each step of the
                    procedures that lead to lease issuance, participation from the affected, States and other interested parties is
                    encouraged and sought
                        The MMS issues the Call/NOI, which is published in the Federal Register, in order to gather information
                    and nominations within a lease planning area from all interested parties. Responses must be received no later
                    than 45 days after publication of the Call/NOI. The information collected from the Call is used to help identify
                    the potential areas for oil and gas development, to help identify issues/concerns of industry, to hell) identify
                    the environmental effects and potential use conflicts in proximity of the area, to initiate the scoping process
                    and identify alternatives to the proposed action for the EIS, to help develop lease terms and conditions, to
                    ensure safe operations, and to help identify potential conflicts between offshore oil and gas activities and a
                    State Coastal Management Program. The NOI is published pursuant to the regulations at 40 CFR 1501.7,
                    implementing the procedural provisions of NEPA (42 U.S.C. 4321 et seq.). The NOI also serves toannounce
                    the scoping process, which affords State and local governments the opportunity to aid MMS in determining
                    significant issues and alternatives to be analyzed in the EIS.
                        When soliciting information for the leasing of lands within 3 mi of the seaward boundary of any coastal
                    State, additional information is provided to the Governors of those States. The Governors must be informed
                    of the identity of, and schedule for, the area proposed for leasing; the geographic, geological, and ecological
                    characteristics of the area within 3 mi of the seaward boundary; estimated oil and gas reserves in these areas;
                    and any field, trap, or geologic structure thought to be located in these areas (43 U.S.C. 1337 (g)). The
                    Secretary subsequently consults with the Governors in determining whether any areas may contain one or more
                    oil or gas pools or fields underlying both the OCS and lands subject    to State jurisdiction. The ultimate goal
                    of the coordination is the fair and equitable disposition of revenues generated by the Federal lease.
                        The Governors are also provided with a summary of data to aid them in anticipating possible onshore
                    effects of OCS development and production. The summary includes estimated oil and gas reserves in areas
                    leased or to be leased, estimated size and timing of development, pipeline locations, and the general location
                    and nature of onshore facilities. The OCSLA, as amended, also requires the transmittal of an index of all
                    relevant actual or proposed programs, plans, reports, EIS's, and other lease-sale information to each affected
                    State (43 U.S.C. 1352 (d)).
                        Pursuant to the Coastal Zone Reauthorization Amendments of 1990, all Federal activities, including OCS
                    oil and gas lease sales, must be consistent with each affected State's CZM program. For presale consistency
                    determinations, MMS reviews the State's coastal zone program, analyzes potential impacts based primarily on
                    the Minerals Management Service's proposed lease sale EIS and the Action Update Memorandum (AUM),
                    and makes an assessment of consistency with the State's program. Consistency determination protocoN for plan
                    and permit activities are discussed in more detail in Section I.13.3.d.(1)(h).
                        Each State's approved CZM program is summarized in Section III.C.6. and an analysis of impacts of the
                    OCS oil and gas leasing program in these State programs is provided in Sections IV.D.Le and IV.D.2.e.
                        The OCS Lands Act requires that DOI prepare a 5-year program that specifies, as precisely as possible,
                    the size, timing, and location of areas to be assessed for Federal offshore natural gas and oil leasing. The
                    Department has developed a new proposed program that will take effect in mid-1992 and last through mid-
                    1997. In keeping with President Bush's June 26, 1990, statement, a new direction for the management of OCS
                    natural gas and oil activities will be taken. The hallmarks of the proposed program include a new planning
                    and consultative process, and a more careful focus on promising geologic basins that appear to be appropriate
                    for leasing and development in an environmentally sound manner. The proposed program represents a new,
                    comprehensive, long-term approach to planning and managing all aspects of natural gas and oil activities off
                    the Nation's coasts.











                                                                                                                                1-15


                    The program provides for a new Area Evaluation and Decision Process (AEDP), which is designed to
               provide more consultations between the Federal Government and the States and localities. The AEDP
               emphasizes three objectives: (a) improving the acquisition and integration of environmental, mineral resource,
               and socioeconomic information to improve the quality of decisions; (b) defining leasing proposals more
               selectively-, and (c) enhancing the opportunities for States, coastal communities, and other concerned parties
               to provide input.
                    The proposed comprehensive program considers 12 lease sales in the Gulf of Mexico for the years 1992
               through 1997 and maintains an annual pace of leasing for the Central and Western Gulf. In the Western Gulf,
               two blocks, which contain the East and West Flower Garden Banks (Blocks A-375 and A-398, High Island
               Area, East Addition, South Extension), have been excluded from leasing consideration. In the Eastern Gulf,
               two sales will be considered (generally west of 840W. longitude and north of 260N. latitude), one in 1994 and
               one in 1997.


               (2) Geological and Geophysical EXPloration RegulationNICoordination

                    Geological and geophysical (G&G) surveys and analyses provide most of the resource and hazards
               information used by government and industry on the offshore areas. The collecting of G&G data begins prior
               to leasing and continues throughout the term of offshore mineral leases.
                    Pursuant to 30 CFR 251.4, a permit or notice must be obtained in order to conduct either geological or
               geophysical exploration for mineral resources or geological or geophysical scientific research of areas of the
               Gulf OCS, except for a lessee on a lease. A permit is approved for a specified period of time of not more than
               I year under which a party has the right to conduct geological or geophysical exploration for mineral resources
               or geological or geophysical scientific research in accordance with the appropriate statutes, regulations, and
               stipulations. A notice is a statement of intent to conduct geological scientific research on the OCS for a
               specified period of not more than a year.
                    "Geological exploration for mineral resources" means any operation conducted on the OCS that uses
               geological and geochemical techniques, including, but not limited to, core and test drilling, well-logging
               techniques, and various bottom-sampling methods to produce information and data on mineral resources,
               including information and data in support of possible exploration and development activity, including pipelines.
               "Geophysical exploration for mineral resources" means any operation conducted on the OCS that uses
               geophysical techniques, including, but not limited to, gravity, magnetic, and various seismic methods to produce
               information and data in support of possible exploration and development activity. "Geological or geophysical
               scientific research" means any investigation conducted on the OCS that uses scientific methods and/or
               techniques to gather and analyze geological and/or geophysical data and information for scholarly or academic
               purposes with no direct commercial application.
                    Permit applications for G&G activity must be submitted to MMS in accordance with the requirements
               outlined in 30 CFR 251.5 and 30 CFR 251.6 and explained further in Letter(s) to Permittees. The Letter to
               Permittees dated January 20, 1989, includes a listing of forms and maps that apply to most G&G permit
               activity. The regulations under 30 CFR 251 do not apply to G&G exploration activities conducted by, or on
               the behalf of, the lessee on a leased block on the Gulf OCS. Geological and geophysical activities by the lessee
               on his existing leases are governed by the regulations in 30 CFR 250 and by the notification procedures for
               explosives, dredging, and geotechnical surveys outlined in the Letter dated November 8, 1990.
                    When required under a CZM program approved under the CZMA, activities proposed by an applicant
               for a G&G permit must receive State concurrence in its coastal zone consistency certification prior to MMS
               approval of any of the activities covered under the permit (30 CFR 251.6-2(c)(1)). The Gulf Coast States are
               not involved in the review process for specific G&G applications prior to issuance of the permit, except for
               continental offshore stratigraphic tests (COST's). The COST's involve penetration into the sea bottom on
               unleased lands that involve more than 15 in (50 ft) of consolidated rock or a total of 91 in (300 ft) of
               unconsolidated material. Shallow test drilling involves drilling into the sea bottom at depths less than those
               specified for COST's. Environmental reports are required in accordance with 30 CFR 251.6-2(c)(2) for
               COST's; and when required under a coastal zone management program, they must receive State concurrence











                  1-16


                  prior to approval of any activities covered under the permit. The plan and report is also made available to
                  appropriate Federal agencies and the public in accordance with established practices and procedures. Shallow
                  test drilling or COST's must use the best available and safest technologies. Additional environmental
                  information may be required for G&G applications proposing the use of solid or liquid explosives. The use
                  of explosives may also lead to initiation by MMS of consultation with the National Marine Fisheries Service
                  (NMFS) under Section 7 of the Endangered Species Act.
                       After receiving a G&G permit application, MMS prepares either a CER, EA, and/orEIS in acoardance
                  with NEPA and other applicable MMS policies and guidelines as described in Section I.B.3.d.(1)(a). A CER
                  is prepared for most G&G permit applications. Activities that include the drilling of COST holes involve the
                  use of solid or liquid explosives, or that otherwise have the potential to significantly affect the quality of the
                  human environment automatically require the preparation of an EA.

                  d. Postsale Activities


                       The MMS is responsible for regulating and monitoring the oil and gas operations on the Federal OCS.
                  The regulations at 30 CFR 250.5 (a) provide for the Director to regulate all operations conducted under a lease,
                  right of use and easement, or DOI pipeline right-of-way to promote orderly exploration, development, and
                  production of mineral resources and to prevent harm or damage to, or waste of, any natural resource, any life
                  or property; or the marine, coastal, or human environment. Prior to either exploration, development, or
                  production activities being conducted in a lease block, other than on-lease preliminary activities, companies
                  must submit plans to MMS for review and approval. Within these plans, specific requirements must be met
                  relative to operating conditions and environmental considerations. The regulations now allow for penetration
                  of the seabed up to 152 in (500 ft) for on-lease preliminary activities, provided such activities do not result in
                  any significant adverse impact on the natural resources of the OCS (30 CFR 250.31). Prior notification is
                  required by MMS for certain on-lease preliminary activities as outlined in the Letter to Lessees and Operators
                  (LTL) dated November 8, 1990, and amended June 21, 1991.

                  (1) Review, Coordination, and Approval of Exploration, Development, and Production Activities

                  (a) Exploration Plans

                       Pursuant to OCSLA (43 U.S.C. 1340) and 30 CFR 250.33, an Exploration Plan (EP) and its supporting
                  information must be submitted for approval to MMS before an operator may begin exploratory drilling on a
                  lease. The EP describes all exploration activities planned by the operator for a specific lease(s), the timing of
                  these activities, information concerning drilling vessels, the location of each well, and other :relevant
                  information. A revised plan is a revision to an approved plan that proposes changes suchas those in surface
                  location, type of drilling unit, or location of the onshore support base. A supplemental plan constitutes a
                  revision to an approved plan that proposes the addition of an activity that requires a permit. An amended plan
                  is any revision to a plan pending approval. Each of these types of plans need contain only that information
                  related to or affected by the proposed revision.
                       The revised rule provides for submission of supporting information for MMS and CZM State evaluation
                  as outlined in 30 CFR 250.33(b)(1) through (21). The operator may limit the amount of information submitted
                  to that which is listed in the LTL dated October 12, 1988, as amended by the LTL dated September 5, 1989.
                  Environmental reports are not considered part of the plan. This was intended in part to eliminate unnecessary
                  duplication. The MMS can require modification of a plan based on inadequate or inaccurate supporting
                  information.
                       The supporting information provides an analysis of both offshore and onshore impacts that may occur as
                  a result of implementation of the plan. In accordance with the CZMA, as amended, EP's requiring State
                  review must contain a certification of consistency with approved CZM programs of States that could be affected
                  by the exploration activities. States with approved programs may take up to 6 months for consistency reviews
                  but must agree with or request an extension within 3 months after receipt of their copy of the EP. In the Gulf











                                                                                                                                1-17


               of Mexico, Louisiana, Mississippi, Alabama, and Florida have federally approved CZM programs. The
               guidelines and environmental information requirements for lessees and operators submitting an EP are
               discussed further in Section I.B.3.d.(1)(e).
                   The MMS prepares a CER, FA or EIS based on available information, which may include the geophysical
               report (for determining the potential for the presence of deep-water benthic communities), archaeological
               report (30 CFR 250.33(b)(15)), air emissions data, live-bottom survey/report (30 CFR 250.33(b)(12)), biological
               monitoring plan (30 CFR 250.33(b)(16)), and recommendations by the affected State(s), the Department of
               Defense (DOD), U.S. Fish and Wildlife Service (FWS) (for selected plans under provisions of a DOI
               agreement), NMFS, and/or internal MMS offices. The MMS evaluates the proposed activity for potential
               impacts relative to geohazards and manmade hazards (including existing pipelines), archaeological resources,
               endangered species, sensitive biological features, water and air quality, oil-spill. response, and other uses (e.g.,
               military operations) of the OCS.
                  The CER's are prepared for certain postlease activities in the WPA and CPA in accordance with 516 DM
               2, Appendix 1 and 516 DM 6, Appendix 10. The eastern extent of the CPA is offshore the State of Alabama
               at approximately longitude 87031' W (consult Visual No. 1 for further details). The criteria used to determine
               which actions are to be excluded from the NEPA process are as follows: (1) the action or group of actions
               would have no significant effect on the quality of the human environment and (2) the action or group of actions
               would not involve unresolved conflicts concerning alternative uses of available resources. The CER's serve as
               a vehicle for a considerable environmental analysis in cases where archaeological, air quality, and biological
               assessments and oil-spill response planning are necessary in early planning.
                   If the CER determines that the proposed action is an exception to the categorical exclusions as listed in
               516 DM 2, Appendix 2, then the preparation of an EA is required. An EA may also be prepared on any
               action at any time in order to assist in planning and decisionmaking (516 DM 3.2.13) or under extraordinary
               circumstances (516 DM 2.4). The EXs are routinely prepared for selected environmentally sensitive areas
               (e.g., for activities proposed within the 4-mile zone of the Flower Garden Banks lease blocks) and for proposed
               activities considered environmentally sensitive (e.g., new or unusual technology and pipeline rights-of-way to
               shore).
                   If the EA indicates that approval of the plan would constitute a major Federal action significantly affecting
               the human environment, that an existing EIS addressing the matter does not exist, or that an existing EIS is
               not current, an EIS must be prepared. On the basis of the EA, CER, or EIS findings and the plan
               completeness review, the EP would be either approved or disapproved, or modification of the plan would be
               required of the operator. The EA would also identify appropriate mitigation of impacts of the proposal.

               (b) Development and Production Plans

                   Pursuant to OCSLA (43 U.S.C. 1351) and 30 CFR 250.34, a development and production plan and its
               supporting information must be submitted for approval to MMS before an operator may begin development
               or production activities. Development and production plans are not required for leases in the Western Gulf
               pursuant to 30 CFR 250.34(d)(1). (In this designation, the Western Gulf includes all areas of the Gulf of
               Mexico except those that are adjacent to the State of Florida as defined previously.) However, information
               covering these leases is required to ensure conformance with the OCSLA, other laws, applicable regulations,
               and lease provisions and to enable MMS to carry out its functions and responsibilities. Therefore, before any
               development and production activity is conducted on a lease in the Western Gulf, the operator must prepare
               and submit to MMS a Development Operations Coordination Document (DOCD) and, as required, supporting
               environmental information, archaeological report, biological report (monitoring and/or live-bottom survey), or
               other environmental data determined necessary. A DOCD shall be considered a development and production
               plan for the purpose of any references in any law, regulation, lease provision, agreement, or other document
               referring to the preparation or submission of a plan. The plan describes a schedule of development activities,
               platforms, or other facilities including environmental monitoring features and other relevant information. Refer
               to Section I.B.3.d.(I)(a) for a discussion of plan revisions. The revised rule provides for submission of











                  1-18


                  supporting information for MMS and State CZM evaluation as outlined in 30 CFR 250.34(to) through (u). As
                  with EP's, MMS can require modification of a plan based on inadequate or inaccurate supporting information.
                      After receiving a DOCD, MMS prepares either a CER, EA, and/or EIS as discussed under EP's above
                  (Section 1.13.3.d.(1)(a)). As part of the review process, the DOCD and supporting environrnental information,
                  as required, are sent to the affected State(s) having an approved CZM plan for consistency certification review
                  and determination. The OCSLA (43 U.S.C. 1345(a)) provides for coordination and consultation with the
                  affected State and local governments concerning a development plan. The guidelines and environmenW
                  information requirements for lessees and operators submitting a development and production plan are
                  addressed in NTL 86-09 and are discussed further in Section 1.13.3.d.(I)(e). On the basis of the CER, EA, or
                  EIS findings and the plan completeness review, the plan would be either approved or disapproved, or
                  modification of the plan would be required of the operator.
                      After plan approval, the operator submits for approval specific applications to MMS, such as those for
                  pipelines and platforms, to conduct activities described in the plan.

                  (c) Oil Spill Contingency Plans

                      Pursuant to 30 CFR 250.33, 30 CFR 250.34, and 30 CFR 250.42, a lessee is required tosubmit an Oil Spill
                  Contingency Plan (OSCP) to MMS for approval with or prior to submitting an EP or DOCD. If an OSCP
                  covering the area, such as a regional plan, has already been approved, it may be referred to in the plan. In
                  order to facilitate this requirement in the Gulf of Mexico OCS Region, an operator may submit a regional plan
                  covering all of their Gulf OCS operations. The approved regional OSCP is then referenced when EP's or
                  DOCD's are submitted. Additionally, certain site-specific, oil-spill-response information is required to
                  accompany a plan when a regional OSCP is referenced. An operator may elect to include; or the MMS may
                  require inclusion of a site-specific OSCP in an EP or DOCD when the approved regional OSCP does not
                  provide adequate oil-spill protection. All regional and site-specific OSCP's are required to be reviewed and
                  updated annually, and all modifications of an OSCP are submitted to MMS for approval. Guidelines outlined
                  in the February 1, 1989, and September 5, 1989, LTL's were developed to aid Gulf OCS operators in the
                  preparation of OSCP's. The OSCP must contain assurances that a full response capability exists for
                  commitment in the event of an oil spill. Such a commitment includes specification of appropriate equipment
                  and materials, their availability and deployment time, and provisions for varying degrees of response effort,
                  depending on the severity of the spill. See Section IV.C.5. for additional information on oil-spill planning.

                  (d) Hydrogen Sulfide Contingency Plans

                      Pursuant to 30 CFR 250.33, 30 CFR 250.34, and 30 CFR 250.67, the operator of a lease requests that
                  MMS make a determination regarding the presence of hydrogen sulfide (1-12S) gas. The MMS classifies an area
                  of proposed operations as (1) a zone known to contain 1-12S, (2) a zone where the presence of H2S is unknown,
                  or (3) a zone where the absence of H2S has been confirmed. An 1-12S Contingency Plan must be submitted for
                  approval prior to conducting operations on a lease when the H2S classification meets the criteria of (1) or (2)
                  and must include contingencies for simultaneous drilling, well-completion, well-workover, and production
                  operations. Pursuant to the LTL dated September 5, 1989, each EP or DOCD must contain a request for a
                  determination for one of the three classifications and a discussion of the basis for the recommendation. The
                  lessee must take all necessary and practicable precautions to protect personnel from the toxic effects of H2S
                  and to mitigate the adverse effects of 1-12S to property and the environment.

                  (e) Environmental Information

                      Pursuant to 30 CFR 250.33 and 250.34, specific environmental information, as discussed in Sections 1, 11,
                  and IV of NTL 86-09 and as prepared in accordance with guidelines in Sections II.A., H.B., or III of the
                  enclosure to NTL 86-09, is required for leases in the Gulf of Mexico for CZM purposes. It should be noted
                  that the term "environmental report" as used in NTL 86-09 is synonymous with the term "environmental











                                                                                                                             1-19


               information"required by the LTL dated October 12,1988. Under the CZMA, each State that has an approved
               CZM plan has the option to require information that is different than that specifically outlined in 30 CFR
               250.33 and CFR 250.34 for inclusion in the plan. Refer to Section I.B.3.d.(1)(h) for a discussion of the Gulf
               Region's procedures for CZM consistency. The States of Louisiana, Mississippi, Alabama, and Florida have
               approved CZM programs. With the exception of Florida, operators submit abbreviated environmental
               information for CZM purposes. Requirements for both the abbreviated format required for the States of
               Alabama, Louisiana, and Mississippi and the long-form format required for activity determined to affect the
               State of Florida are given in the LTL dated October 12, 1988 (NTL 86-09 incorporated therein by reference).
               The operating regulations recognize the possible significance of proposed modifications to approved plans and
               provide for CZM agency review of modifications.
                   Additional environmental information may also be required for plans/activities in the Western Gulf of
               Mexico for the following: (1) areas of high seismic risk or seismicity and relatively untested deep-water and
               remote areas; (2) areas proposed or established as a marine sanctuary and/or near the boundary of a proposed
               or established wildlife refuge or areas of high ecological sensitivity (e.g., East and West Flower Garden Banks);
               (3) areas of potentially hazardous natural bottom conditions; or (4) the use of new or unusual technology, when
               the additional information is required to evaluate impacts. Environmental information requirements will be
               determined on a case-by-case basis for plans meeting any of the four categories, with the exception of plans
               submitted that propose activities within the restrictive zones of the Flower Garden Banks. The Guidelines
               enclosure of NTL 86-09 outlines the information requirements for activities proposed within the 4-mile zone
               of the Flower Garden Banks. Specific information is required for structure-removal applications as outlined
               in LTL's dated August 19 and December 9, 1986. The submission of specific supporting information to aid
               in evaluating the environmental impacts of plans/activities may be required by MMS under 30 CFR
               250.33(b)(21) and 30 CFR 250.34(b)(15) in areas of the Central and Western Gulf where either no
               environmental information is required or an abbreviated format is required for CZM purposes.

                    Air Emissions Information

                   The OCSLA at 43 U.S.C. 1334(a)(8) requires the Secretary to promulgate and administer regulations to
               provide for compliance with the National Ambient Air Quality Standards (NAAQS) pursuant to the Clean Air
               Act (42 U.S.C. 7401 et seq.) to the extent that authorized activities significantly affect the air quality of any
               State. The Clean Air Act Amendments of 1990 state that no later than 12 months after the enactments of the
               amendments, USEPXs Administrator, in consultation with the Secretary of the Interior and the Commandant
               of the Coast Guard, will establish the requirements to control air pollution in the OCS areas of the Pacific,
               Atlantic, Arctic, and eastward of 87031'W. longitude in the Gulf of Mexico. Sources located within 25 mi of
               the seaward boundary of those States under USEPA!s jurisdiction shall be subject to requirements similar to
               onshore sources. For sources located in other areas, regulation is accomplished through 30 CFR 250.44, 250.45,
               and 250.46, and is administered by MMS as a postsale activity. It is the intent of these regulations to protect
               onshore ambient air quality and to ensure that no new violations of NAAQS are caused by the OCS activity.
               The regulated pollutants are carbon monoxide, suspended particulates, sulphur dioxide, nitrogen oxides, and
               volatile organic compounds. In areas where hydrogen sulfide may be present, operations are regulated by 30
               CFR 250.67 and are discussed in Section I.B.3.d.(l)(d). Emissions data concerning new or modified onshore
               facilities (directly associated with offshore activities) are required to enable each affected State to make a
               determination of the effects on its air quality.
                  Exploration plans and DOCD's address activities that are determined by the Secretary as activities regulated
               under 30 CFR 250.44, 250.45, and 250.46. All new or supplemental EP's and DOCD's submitted on or after
               June 2, 1980, must include air emissions information sufficient to make an air quality determination. The LTL
               dated October 12, 1988, outlines air emissions data that must be submitted by operators. The Clean Air Act
               Amendments of 1990 also require that MMS conduct and complete a study of the effects of offshore air
               emissions in nonattainment onshore areas within 3 years after the approval of the amendments in OCS areas
               not under USEPA jurisdiction.











                  1-20

                  (g) Site Clearance

                      The MMS has established a program to ensure that any object (e.g., well heads, platforms, etc.) installed
                  on an OCS lease is properly removed and the site cleared so as not to conflict with other uses of the OCS.
                  The minimum requirements for site clearance and verification were addressed in NTL 90-031, which was issued
                  on February 28, 1990. The MMS formed a site clearance committee comprised of representatives of the oil
                  and gas and shrimping industry, the State of Louisiana, Jefferson Parish, and the MMS to address apparent
                  inadequacies in certain site clearance procedures and verification techniques that had been reported by the
                  shrimping industry. Based on the recommendations of the committee, interim procedures 1br the verification
                  of all OCS structure removals and site clearance activities was signed as NTL 90-03 by the MMS, Gulf of
                  Mexico Region on August 27, 1990. This interim document will allow the industry, committee, and MMS to
                  continue monitoring various site clearance efforts and verification techniques and to continue gathering data
                  for evaluation and consideration when formulating modifications to MMS operating regulations.
                      The use of explosives to cut offshore oil/gas structure legs/pilings for removal could cause injury or death
                  to protected marine mammals and endangered sea turtles. Lessees/operators must notify MMS 30 days before
                  a structure removal and provide information including the following: complete identification of the structure;
                  size of the structure (number and size of legs and pilings); removal technique to be employed (if explosives are
                  to be used, the amount and type of explosive per charge); and the number and size of well conductors to be
                  removed and the removal technique (see LTL:s dated August 19 and December 9, 1986). Structure-removal
                  requests are reviewed on a case-by-case basis. Currently, if a structure removal involves the use of explosives,
                  -an environmental assessment is prepared and an Endangered Species Section 7 Consultation is initiated with
                  NWS. The NMFS issued a "standard" Biological Opinion on July 25, 1988, which covers removal operations
                  that meet specified criteria pertaining to the size of explosive charge used, detonation depth, and number of
                  blasts per structure grouping. The MMS, NMFS, and lessees are cooperating in an observer/monitoring
                  program to determine the presence of marine mammals and/or sea turtles in the vicinity of the structure
                  removals. Additional information on structure removals is found in Section IV.A.2.a.(3).

                  (h) Coastal Zone Management Consistency Review and Appeals for Plans

                  Gulf of Mexico OCS Region's Procedures for CZM Consistency

                      Pursuant to the CZMA, 16 U.S.C. 1451 et. seq. (Section 307), a State with an approved CZM plan reviews
                  certain OCS activities to determine whether they will be conducted in a manner consistent with their approved
                  plan. This review authority is applicable to activities described in detail in any plan for the exploration or
                  development of any area that has been leased under the OCSLA and that affects any land or water use or
                  natural resource within or outside of the State's coastal zone (16 U.S.C. 1456(c)(3)(B)). The MMS may not
                  issue a permit for activities described in a plan unless the State concurs or is conclusively presumed to have
                  concurred that the plan is consistent with its CZM plan (43 U.S.C. 1340(c) and 1351(d); 16 U.S.C. 1456(c)(3)).
                      In accordance with the requirements of 15 CFR 930.76(b), the MMS Gulf of Mexico OCS Region sends
                  copies of an EP and DOCD--including the consistency certification and other necessary information--to the
                  designated State CZM agency by receipted mail. See Section I.B.3.d.(l)(e) for a discussion of environmental
                  information requirements for leases in the Gulf of Mexico submitted for CZM purposes. The Region monitors
                  the consistency-review time period because 15 CFR 930.79(a) and (b) require that concurrence by the State
                  agency shall be conclusively presumed in the absence of a State-agency objection when the appropriate review
                  period expires. Similar procedures are followed for amended plans.
                      If a written consistency concurrence is received from the State, the Region may then approve any permit
                  for activities described in the plan in accordance with 15 CFR 930.63(c). The Gulf Region does not impose
                  or enforce additional State conditionswhen issuing permits. The MMS can require modification of a plan even
                  if the operator has agreed to certain requirements requested by the State and agreed to by the operator.
                      If the Gulf Region receives a written consistency objection from the State containing all the items required
                  in 15 CFR 930.79(c) before the expiration of the review period, the Region will not approve any permit for











                                                                                                                                  1-21


                 an activity described in the plan unless (1) the operator amends the plan to accommodate the objection in
                 accordance with 15 CFR 930.83 and concurrence is subsequently received or conclusively presumed; (2) upon
                 appeal, the Secretary of Commerce, in accordance with 15 CFR 930.120, finds that the plan is consistent with
                 the objectives or purposes of the CZMA or is necessary in the interest of national security; or (3) the original
                 objection is declared invalid by the courts.

                 Coastal Zone Consistency Appeals

                     A State determination that a proposed activity is not consistent with its approved program must be made
                 within 6 months, and the State must notify the applicant. States often object on the grounds of insufficient
                 information or that the proposal is inconsistent with a mandatory State program requirement. The State
                 objection must describe (1) how the proposed activity will be inconsistent with specific elements of the
                 management program and (2) alternative measures, if they exist, which, if adopted by the applicant, would
                 permit the proposed activity to be conducted in a manner consistent with the management program. Further,
                 the State must inform the applicant of the right of appeal to the Secretary of Commerce (15 CFR 930.64).
                 The applicant has 30 days from receipt of the objection to file a notice of appeal with the Secretary. The
                 applicant may appeal on two independent grounds. First, the applicant may state that the activity furthers the
                 purposes or objectives of the CZMA or, second, that the activity is necessary in the interest of national security.
                 The notice of appeal must be accompanied by a statement in support of the applicant's position, along with
                 supporting data and information. Copies of the notice and supporting material must be sent to relevant
                 Federal and State agencies. An Ex-Partt process applies to appeals to the Department of Commerce. The
                 merits of an appeal cannot be discussed unless all parties are present (National Oceanic and Atmospheric
                 Administration (NOAA), Office of Ocean and Coastal Resources Management (OCRM) exempted). The
                 Secretary may order a public hearing on his own volition or at the request of an interested party. If the
                 Secretary holds a hearing, the NOAA General Counsel or his designee presides as hearing officer. A Federal
                 Register notice is prepared to inform the public of the hearing. The regulations covering the appeals process
                 are found at 15 CFR 930, Subpart H.

                 (2) Enforcement Measures

                 (a) Inspections

                     The MMS inspection program in the Gulf of Mexico is directed by the OCS Regional Office in New
                 Orleans, Louisiana, and six local offices that provide day-to-day review and inspection of oil and gas operations.
                 There are 68 inspectors that go offshore every day, weather permitting. During FY 90, the Gulf of Mexico
                 Region conducted 1,677 drilling inspections, 4,830 production inspections, 2,822 measurement inspections, and
                 361 pipeline inspections. The MMS also inspects the stockpiles of industry's equipment for the containment
                 and cleanup of oil spills. Stockpiles are located at nine strategic sites along the Gulf Coast. The MMS has
                 instituted a program to land unannounced at an operator's facility to conduct a surprise drill to test the
                 company's ability to deal with an oil spill.
                     The OCSLA (43 U.S.C. 1348(c)) requires MMS to conduct onsite inspections to assure compliance with
                 lease terms, NTL's, and approved plans and to assure that safety and pollution-prevention requirements of
                 regulations are met. These inspections involve items of safety and environmental concern. Further information
                 on the baseline for the inspection of lessee operations and facilities can be found in the National Potential
                 Incidentof Noncompliance (PINC) List (USDOI, MMS, 1988a). Noncompliance with checklisted requirements
                 for specific installations or procedures is followed by prescribed enforcement actions consisting of written
                 warnings or shut-ins of platforms, zones (wells), equipment, or pipelines. In some cases, more than one
                 enforcement action is noted. The MMS inspector then determines the appropriate enforcement action based
                 on an assessment of the risk of either pollution or accident, the history of the lessee, the stage of operation in
                 progress, and the status of other systems.











                  1-22

                      If an operator is found in violation of a safety or environmental requirement, a citation is issued requiring
                  that it be fixed within 7 days. The violation may call for the particular well component or the entire complex
                  to be shut in.
                      The primary objective of initial inspections is to assure proper installation of mobile units or structures and
                  associated equipment After operations begin, additional announced and unannounced inspections are held.
                  Surprise unannounced inspections are conducted to foster a climate of safe operations, to maintain an MMS
                  presence, to focus on operators with a poor performance record, and when a critical safety feature has
                  previously been found defective. Depending on the distance from shore and other factors such as weather and
                  proximity to other inspections, MMS district personnel inspect from one to three different rigs or platforms
                  per day. Aerial surveillance of additional offshore structures is conducted enroute. Annual inspections are
                  conducted on all platforms, but more frequent inspections may be conducted on rigs and platforms. On-board
                  inspections involve the inspection of all safety systems of a production platform. In the interest of efficient and
                  effective utilization of inspection resources, random sampling techniques are being evaluated for the selection
                  of specific items for inspection from the national PINC list.
                      The operator will normally request the use of ofl-based (e.g., mineral oil or polymers) muds at the
                  Application for Permit to Drill (APD) stage if problems are anticipated or if problems are encountered during
                  drilling. Cuttings associated with ofl-based muds are generally transported to shore for disposal. Drilling mud
                  is usually reused because of its high cost. Inspectors try to visit operations using oil-based muds frequently or
                  at least make an effort to "fly-by" when in the area. Of initial importance to inspectors Ls the presence or
                  absence of a "visible sheen" in the waters adjacent to a rig using oil-based muds or a platform producing
                  hydrocarbons. On-board inspection involves seeing that the muds and cuttings are being properly treated
                  and/or disposed of. The "bucket test" involves dropping 2-3 handfuls of cuttings into a bucket of seawater to
                  test for residual oil. The bucket test is a crude indication of the level of treatment when cuttings are treated
                  prior to discharge offshore. The bucket test may be used to ensure that water-based muds will not cause a
                  sheen. The presence or absence of a "visible sheen" in the bucket determines whether or not the cuttings are
                  being properly treated prior to being dumped. This sheen test, performed by MMS inspectors, is different than
                  the "visible sheen" test required under the U.S. Environmental Protection Agency's NPDES general permit for
                  the Gulf of Mexico.
                      District personnel inspect H2S sensors to make sure they are operational and inspect logs for timely
                  calibration of instruments and to ensure that rig personnel have been trained in appropriate equipment
                  handling, safety regulations, and emergency procedures. The revised rule for H2S protection requirements and
                  procedures has been expanded to include production, well-completion, and well-workover operations as well
                  as drilling operations. Hydrogen sulfide presents a threat to human life and safety and to the survival of
                  equipment.

                  (b) Suspension of Operations

                      The OCSLA as amended (43 U.S.C. 1334(a)(1)), and regulations appearing at 30 CFR ' 250.10 provide for
                  the suspension or temporary prohibition of an operation or activity when the suspension is in the national
                  interest and when the suspension is necessary based on any of the conditions given at 30 CFR 250.10(a)
                  through (c).

                  (c) Cancellation of Leases

                      The OCSLA (43 U.S.C. 1334(a)(2)) and regulations at 30 CFR 250.12 authorize the Secretary to cancel
                  a lease or permit if, after opportunity and notice for a hearing, he determines (1) continued activity would
                  probably cause serious harm or damage to life, property, the environment, or national security or defense; (2)
                  the threat of harm or damage will not disappear or decrease to an acceptable extent within at reasonable time;
                  (3) the advantages of cancellation outweigh the advantages of continued activity; and (4) the suspension has
                  been in effect for at least 5 years or the termination of suspension and lease cancellation are at the request
                  of the lessee.












                                                                                                                                 1-23

               (d) Remedies and Penalties

                    Under 43 U.S.C. 1350(b) of the OCSLA, as amended, and regulations appearing at 30 CFR 250.200-.206,
               civil penalties can be assessed for failure to comply with responsibilities under the law, a license, a permit, or
               any regulation or order issued pursuant to the Act The Oil Pollution Act of 1990 update has changed the way
               MMS will address civil remedies and penalties in the future. If the violation is serious enough and is found
               to be a knowing and willful violation, MMS may recommend that the matter be referred to the Department
               of Justice for criminal prosecution (43 U.S.C. 1350(c)). The issuance and continuance in effect of any lease
               or of any assignment or other transfer of any lease shall be conditioned upon compliance with regulations
               issued under the OCSLA

               (3) Environmentd Safeguards

               (a) OCS Regulations

                    On April 1, 1988, revised regulations (30 CFR 250 and 256) that restructured and consolidated the rules
               governing OCS exploration, development, and production activities were published in the Federal Register and
               became effective May 31, 1988. The former Gulf of Mexico OCS Orders, which dealt with the technical
               aspects of OCS activities, have been incorporated into the new rules (53 FR 10596-10777).

               Approvals

                    Pursuant to 30 CFR 250.4(a), the Director of MMS is authorized to act upon the requests, applications,
               and notices submitted to the agency to issue either written or oral orders to govern lease and right-of-way
               operations. He is also authorized to require compliance with applicable laws, regulations, and lease terms so
               that all operations conform to sound conservation practice and are conducted in a manner that will preserve,
               protect, and develop mineral resources of the OCS.

               Best Available and Safest Technologies

                    To assure that off and gas exploration, development, and production activities on the OCS are conducted
               in a safe and pollution-free manner, 43 U.S.C. 1347(b) of the OCSLA, as amended, requires that all OCS
               technologies and operations use the best available and safest technology (BAST) that the Secretary determines
               to be economically feasible. Conformance to the standards, codes, and practices referenced in 30 CFR 250
               are considered to be the application of BAST. These include requirements for state-of-the-art drilling
               technology, production safety systems, completion of oil and gas wells, oil-spill contingency plans, pollution-
               control equipment, and specifications for platform/structure designs. The MMS conducts periodic offshore
               inspections, and the Engineering and Technology Division continuously and systematically reviews OCS
               technologies to ensure that the best available and safest technologies are applied to OCS operations. The
               BAST is not required when the Secretary determines that the incremental benefits are clearly insufficient to
               justify increased costs (30 CFR 250.5(b)); however, it is the responsibility of an operator on an existing
               operation to demonstrate why application of a new technology would not be feasible. This requirement is
               applicable to equipment and procedures that, if failed, would have a significant effect on safety, health, or the
               environment, unless benefits clearly do not justify the cost.
                    The BAST concept is addressed in the Gulf of Mexico OCS Region by a continuous effort to locate and
               evaluate the latest technologies and to report on these advances at periodic Regional Operations Technology
               Assessment Committee (ROTAC) Meetings. A part of the MMS staff has an ongoing function to evaluate
               various vendors and industry representatives' innovations and improvements in techniques, tools, equipment,
               procedures, and technologies applicable to oil and gas operations (drilling, producing, completion, and workover
               operations). This information is provided to MMS district personnel at ROTAC meetings. The requirement
               for the use of BAST has, for the most part, been an evolutionary process whereby advances in equipment,











                   1-24

                   technologies, and procedures have been subtly integrated into OCS operations over a period of time. An
                   awareness by both MMS inspectors and the OCS operators of the most advanced equipment and technologies
                   has resulted in the incorporation of these advances into day-to-day operations. An example of such an
                   equipment change that evolved over a period of time would be the upgrading of diverter systems on drilling
                   rigs from the smaller diameter systems of the past to the large-diameter, high-capacity systerns found on drilling
                   rigs operating on the OCS today. Another example of a BAST-required equipment change would be the
                   requirementto replace subsurface-controlled subsurface safety valves with surface-controlled, subsurface safety-
                   valve systems, which incorporate a more positive closure design and operation. Also, a qULlity assurance and
                   performance of safety and pollution-preventionequipment program regarding the surface and subsurface safety
                   valves has been included in MMS requirements.

                   Pollution Prevention and Control

                       The MMS has promulgated regulations (30 CFR 250.40) to ensure lessees do not create conditions that
                   will pose an unreasonable risk to public health, life, property, aquatic life, wildlife, recreation, navigation,
                   commercial fishing, or other uses of the ocean during offshore oil and gas operations. Control and removal
                   of pollution is the responsibility and at the expense of the lessee. Operators are required to install curbs,
                   gutters, drip pans, and drains on platform and rig deck areas in a manner necessary to collect all contaminants
                   and debris not authorized for discharge. The rules also explicitly prohibit the disposal of equipment, cables,
                   chains, containers, or other materials into offshore waters. Portable equipment, spools or reels, drums, pallets,
                   and other loose items weighing 40 lb or more must be marked in a durable manner with the owner's name
                   prior to use or transport over offshore waters. Smaller objects must be stored in a marked container when not
                   in use. Should equipment, material, containers, drums, or other items be lost overboard, they are to be
                   recorded on the facility's daily report and reported to the MMS. Discussion of regulations specifically
                   pertaining to oil-spill prevention can be found in Section IV.C.5.

                   (b) OCS Structures and Equipment

                   Wells


                       Prior to conducting drilling operations, the operator is required, pursuant to 30 CFR 250.64, to submit and
                   obtain approval for an APD (Form MMS-331C). The lessee is required to take precautions to keep
                   exploratory well drilling under control at all times. The APD is filed by the lessee/operator along with or
                   following submission of the EP or DOM and supporting information. The APD requires detailed information
                   about the drilling program for evaluation with respect to operational safety and pollution-prevention measures.
                   Approval of an APD requires an MMS-approved EP or DOM and receipt of C7A consistency or
                   presumptive concurrence. The approved APD constitutes the drilling permit. The API) is reviewed for
                   conformance with the requirements of 30 CFR 250.64 and other engineering considerations. In addition, other
                   information--includingproject layout at a scale of 2,000 ft to the inch, design criteria for well control and casing,
                   blowout preventors, and a mud program--is required. The lessee must use the best available and safest
                   technology in order to enhance the evaluation of abnormal pressure conditions and to minimize the potential
                   for uncontrolled well flow. Specific requirements for well workovers, completions, abandonments, and sundry
                   notices are detailed in Subparts D-G of the revised regulations. Significant deviations from an approved plan
                   require that an environmental analysis be done in accordance with the procedures outlined in Section
                   I.B.3.d.(1)(a).

                   Platforms

                       The lessee must design, fabricate, install, use, inspect, and maintain all platforms and structures on the OCS
                   to assure their structural integrity for the safe conduct of operations at specific locations. Applications for
                   platform approval are filed in accordance with 30 CFR 250.131. Design requirements are presented in detail











                                                                                                                               1-25

              at 30 CFR 250.134-250.139. The lessee evaluates characteristic environmental conditions associated with
              operational functions to be performed. Factors such as waves, wind, currents, tides, temperature, and the
              potential for marine growth are considered. In addition, pursuant to 30 CFR 250.132 and 250.133, a program
              to assure that offshore oil and gas structures are designed, fabricated, and installed using standardized
              procedures to prevent structural failures has been established by MMS for new platforms meeting the criteria
              at 30 CFR 250.130(c). The program facilitates review of these structures and utilizes third-party expertise and
              technical input in the verification process through the use of a Certified Verification Agent An environmental
              analysis would be conducted for any proposal involving the use of new or unusual technology in accordance
              with the procedures outlined in Section 1.13.3.d.(l)(a).

              Production Facilities

                  Production safety equipment used on the OCS must be designed, installed, used, maintained, and tested
              in a manner to assure the safety and protection of the human, marine, and coastal environments. All tubing
              installations open to hydrocarbon-bearing zones below the surface must be equipped with safety devices that
              will shut off the flow from the well in the event of an emergency, unless the well is incapable of flowing. All
              surface production facilities, including separators, treaters, compressors, headers, and flowlines must be
              designed, installed, and maintained in a manner that provides for efficiency, safety of operations, and protection
              of the environment. Surface- and subsurface-controlled safety valves and locks must conform to the
              requirements of 30 CFR 250.126. Production facilities also have stringent requirements concerning electrical
              systems, flowlines, engines, and firefighting systems. The safety-system devices are tested by the lessee at
              specified intervals and must be in accordance with API RP 14 C, Appendix D, and other measures.

              Pipelines

                  Regulatory processes and jurisdictional authority concerning pipelines on the OCS and in coastal areas are
              shared by several Federal agencies, including DOI, the Department of Transportation (DOT), U.S. Army Corps
              of Engineers (COE), the Federal Energy Regulatory Commission (FERC), and U.S. Coast Guard (USCG).
              Aside from pipeline regulations, these agencies have the responsibility of overseeing and regulating the
              following areas: the placement of structures on the OCS and pipelines in areas that affect navigation; the
              certification of proposed projects involving the transportation or sale of interstate natural gas, including OCS
              gas; the right of eminent domain exercised by pipeline companies; and wellhead pricing controls for certain
              gas produced on the OCS. In addition, the Office of Pipeline Safety (DOT) is responsible for promulgating
              and enforcing safety regulations for the transportation in or affecting interstate commerce of natural gas,
              liquefied natural gas (LNG), and hazardous liquids by pipeline. This includes all offshore pipelines on State
              lands beneath navigable waters and on the OCS. The regulations are contained in 49 CFR 191-193 and 195.
              In the past, MMS requested that affected States render a CZM consistency determination for offshore right-of-
              way pipeline applications. However, the publication of 30 CFR 250, Subpart J, on April 1, 1988, MMS has
              not requested such determinations from the affected States.
                  In a Memorandum of Understanding (MOU) between DOT and DOI dated May 6, 1976, each party's
              respective regulatory responsibilities are outlined. The DOT is responsible for establishing and enforcing
              design, construction, operation, and maintenance regulations for pipelines extending to the shore from the
              outlet flange of an offshore facility. The DOI's responsibility extends upstream from the outlet flange at each
              facility where produced hydrocarbons are first separated, dehydrated, or otherwise processed to each
              production well in the OCS. In addition, those pipelines necessary for the development of a lease are under
              DOI's exclusive jurisdiction.
                  The MMS pipeline permit applications are filed under Subpart J of 30 CFR 250. Detailed requirements
              for filing the applications are found at 30 CFR 250.157 and 30 CFR 250.160. Normally, each permit
              application will contain the pipeline location drawing, profile drawing, safety schematic drawing, and the pipe
              design data to scale. Information submitted as part of the shallow hazard survey report/analysis and/or
              archaeological report is used for MMS environmental evaluations. Provisions governing offshore pipelines
              under the revised rulemaking include expanded requirements governing design, installation, testing, safety











                     1-26

                     equipment, abandonment, and reporting. A Gulf of Mexico Region LTL dated April 18, 1.991, further details
                     and interprets pipeline regulations.
                        In considering applications for pipeline permits, MMS approves the design and fabrication of the pipeline
                     and prepares a CER, EA, and/or EIS in accordance with applicable policies and guidelines. The MMS
                     prepares an EA and/or an EIS on all pipeline rights-of-way that go ashore (pursuant to 516 DM 6, Appendix
                     10). The FWS reviews and provides comments on applications for pipelines that are near certain sensitive
                     biological communities. No pipeline route will be approved by MMS if any bottom-disturbing activities (the
                     pipeline itself or the anchors of lay barges and support vessels) encroach on any biologically sensitive areas,
                     such as stipulation-established No Activity Zones (Sections II.A-1.c.(1) and 113.1.c.(1)). The operators are
                     required to inspect their routes at time intervals and methods prescribed by the Regional Supervisor for any
                     indication of pipeline leakage (30 CFR 250.155(a)). Pipelines routes in the Gulf of Mexico are inspected
                     monthly for leakage through flyovers. In October 1990, Congress amended (through H.R. 4888) Section 3 of
                     the Natural Gas Pipeline Safety Act of 1968 (49 U.S.C. App. 1672) relating to offshore pipeline inspection and
                     burial. In the future, operators of offshore pipeline facilities in the Gulf and its inlets shall inspect the facility
                     and report to the Secretary on any portion of the pipeline facility that is exposed or is a hazard to navigation.
                     This legislation applies only to pipeline facilities between the mean high-water mark and the point where the
                     surface is under 15 ft of water as measures from mean low water. Pipelines may be abandoned in place if they
                     do not constitute a hazard to navigation and commercial fishing or unduly interfere with other uses of the OCS.
                     Procedures for pipeline abandonment and pipeline reporting requirements are outlinedin detail at 30 CFR
                     250.156 and 150.158.

                     (c) Lease Stipulations

                         Oil and gas exploration and development activities on the OCS have the potential for causing adverse
                     environmental impacts; therefore, special stipulations may be developed before the sale (discussed in Sections
                     11 and IV) and may be attached to the lease instrument, as necessary, in the form of additional mitigating
                     measures. Biological communities, archaeological resources, and military areas stipulations are those that have
                     been attached most often to the leases in previous Gulf lease sales. The MMS is responsible for ensuring full
                     compliance with stipulations appended to leases.

                     (d) Other MMS Environmental Safety Controls

                         Besides its regulations and lease stipulations, MMS has other mechanisms that may be used to control or
                     mitigate environmental or safety problems that may arise.

                     Notices, Letters, and Information to Lessees and Operators

                         Notices to Lessees and Operators (NTL's) are formal documents that provide clarification, description, or
                     interpretation of a regulation or OCS standard; provide guidelines on the implementation of a special lease
                     stipulation or regional requirement; provide a better understanding of the scope and meaning of a regulation
                     by explaining MMS interpretation of a requirement; or transmit administrative information such as current
                     telephone listings and a change in MMS personnel or office address. A detailed listing of Gulf of Mexico
                     NTL's was published in the Federal Register on May 16, 1991 (56 FR 22735-22737).
                        The NTL 89-01, adopted subsequent to the latest publication, concerns the Implementation of Consistent
                     Biological Stipulation Measures in the Central and Western Gulf of Mexico.
                         The MMS also conveys important information by way of Letters to Lessees and Operators (LTL's) and
                     Information to Lessees and Operators (ITL's). These documents further clarify or supplement operational
                     guidelines. Separate Regional mailings and the EIS process have served as the vehicles for communicating
                     previous NTL's, LTL's, and ITL's that have been issued.











                                                                                                                            1-27


              Conditions of Approval

                  Conditions of plan approval are mechanisms used by MMS to control or mitigate potential environmental
              or safety problems associated with a proposal. These mechanisms represent an integration of review results
              from other Federal and State agencies (as applicable) and MMS technical evaluations (including geological and
              geophysical; royalty, Suspension of Production schedule, and competitive reservoir considerations; potentially
              hazardous situations involving existing or proposed pipelines; conflicts with archaeological resources and
              sensitive biological areas, and other uses; and NEPA compliance).
                  Alternatives to a proposed action are evaluated as part of the NEPA process to assess reasonable
              alternative activities that could result in lower adverse environmental impacts. In addition to alternatives
              proposed by the lessee/applicant, alternatives that consider other uses of resources that involve unresolved
              conflicts, as well as alternatives or mitigation that are not part of the proposal that may be needed to minimize
              environmental effects, are given full consideration. Mitigating measures have addressed resource-use concerns
              such as endangered/threatenedspecies, geologic and manmade hazards, military warning and ordnance disposal
              areas, oil-spill contingency planning, chemosynthetic communities, operations in H2S prone areas, and shunting
              of drill effluents in the vicinity of biologically sensitive features.
                  Conditions that may be necessary to provide environmental protection may be applied to any OCS plan,
              permit, right of use of easement, or pipeline right-of-way grant.

              Personnel Training and Education

                  An important factor in ensuring that offshore oil and gas operations are carried out in a manner that
              emphasizes operational safety and minimizes the risk of environmental damage is the proper training of
              personnel. Under 30 CFR 250.43(a), all operators must have trained personnel to operate oil-spill cleanup
              equipment or must have retained a trained contractor(s) that will operate the equipment for them. The
              Drilling Well-Control Training Program, now incorporated under 30 CFR 250.211, was instituted by MMS in
              1979. In 1982 and 1983, an additional training program--the Safety Device Training Program--was developed
              and put into effect. The Safety Device Training Program, incorporated under 30 CFR 250.212(a), ensures that
              personnel involved in installing, inspecting, testing, and maintaining safety devices are qualified.
              (e) Prevention and Control Regulations for Spills and Discharges

                 There are a number of important acts under which regulations have been promulgated to minimize
              pollution incidents and the potential environmental and economic damage caused by the release of pollutants
              from various sources into Gulf waters. These acts include the Clean Water Act; OCSLA, as amended (Section
              I.B.3.a.); the Ports and Waterways Safety Act (Section I.B.4.a.); Comprehensive Environmental Response,
              Compensation, and Liability Act of 1980 (CERCLA), or "Superfund," as amended by the Superfund
              Amendments and Reauthorizations Act of 1986 (SARA) (Section 1.13.3.d.(3)(f); and the Oil Pollution Act of
              1990, signed into law on August 18, 1990. There are also a number of international regulations, which the U.S.
              is a signatory to, that prevent or limit water pollution.
                 Also, the USCG has promulgated regulations on oil pollution prevention for vessel transfer facilities (USCG
              regulations do not apply to pipelines) (33 CFR 154), requirements for the reporting of oil discharges (33 CFR
              153), and regulations relating to discharges from ships (33 CFR 155).

              Federal Water Pollution Control Act (Clean Water Act)

                 The Federal Water Pollution Control Act (FWPCA) of 1972 (33 U.S.C. 1251 et seq.), as amended, and
              commonly called the Clean Water Act (CWA), provides a major tool to the Federal Government to ensure
              that the chemical, physical, and biological integrity of the Nation's waters are maintained. The Clean Water
              Act of 1987 expanded and strengthened the FWPCA by building on progress already made in water quality
              and by addressing new and remaining problems.











                  1-28

                      Section 311 of FWPCA, provides the authority for the Federal government's oil spill program. The Oil
                  Pollution Act of 1990 (OPA) contained significant modifications to many of the provisions of Section 311 of
                  the Clean Water Act Major provisions of Section 311 authorizes the Federal Government to

                           (1)    establish reporting criteria for notiPling the Federal Government of discharges
                                  of oil and hazardous substance into U.S. waters;

                           (2)    respond to oil and hazardous substances discharges, including directing cerlain
                                  cleanups by responsible parties;

                           (3)    assess civil and criminal penalties;

                           (4)    establish regulations requiring procedures, methods, and equipment to prevent
                                  discharges;

                           (5)    republish the National Oil and Hazardous Substances Pollution Contingency
                                  Plan (NCP), incorporating OPA changes;

                           (6)    establish area committees to prepare area contingency plans;

                           (7)    promulgate regulations requiring a facility owner or operator to prepare a plan
                                  for responding to a worst-case discharge and to a substantial threat of such a
                                  discharge.

                      Responsibility for implementing Section 311 is divided between USEPA and the DOT by Executive Order
                  11735. In general, DOT is responsible for regulations governing vessels and pipelines, while USEPA is
                  responsible for fixed facilities. Within DOT, the U.S. Coast Guard and the Office of Pipeline Safety have
                  responsibility for implementing Section 311.
                      Recently, USEPA proposed revisions in the Oil Pollution Prevention regulations (40 CFR 112) promulgated
                  under Section 311 (j)(1)(C) of the CWX as amended by OPA. This proposed rule establishes requirements
                  for Spill Prevention, Control, and Countermeasures (SPCC) Plans to prevent spills of oil by nontransportation-
                  related onshore and offshore facilities into the waters of the U.S. and adjoining shorelines. If finalized, these
                  regulations would apply to OCS onshore oil storage areas. The USEPA proposes to exempt offshore
                  productidn or exploration facilities subject to MMS regulations.
                      Title III of the FWPCA requires the USEPA to establish national effluent limitation standards for point
                  sources of wastewater discharges. Title IV of the Act establishes requirements for Federal permits and licenses
                  to conduct an activity (including construction or operation of facilities) that may result in any discharges into
                  waters, called the National Pollutant Discharge Elimination System (NPDES). Section 402: of the Act confers
                  authority upon USEPA to issue permits for the discharge of pollutants into territorial seas and oceans only
                  when the discharges are in compliance with the ocean discharge criteria guidelines established under the
                  authority of Section 403(c) of the Act.

                  Operational Wastes Disposal and Storage Regulations

                      The disposal of oil and gas operational wastes are managed by USEPA through regulations established
                  under three Federal Acts. The Resource Conservation and Recovery Act (RCRA), as amended (42 USC 6901,
                  et seq.), provides a framework for the safe disposal of discarded materials, regulating the management of solid
                  and hazardous wastes. The USEPA has exempted many oil and gas wastes from coverage under hazardous
                  wastes regulations under Subtitle C of RCRA- If covered, such wastes would be more stringently regulated
                  under hazardous waste rules, i.e., industry would be responsible for the wastes from their generation to their
                  final disposal. Exempt wastes include those generally coming from an activity directly associated with the











                                                                                                                             1-29

               drilling, production, or processing of a hydrocarbon product. Nonexempt off and gas wastes include those not
               unique to the oil and gas industry and used in the maintenance of equipment.
                   The direct disposal of operational wastes into offshore waters are limited by USEPA under the authority
               of the Clean Water Act, as amended. A general National Pollution Discharge Elimination System (NPDES)
               Permit, based on effluent limitation guidelines, is required for all such discharges. On July 9, 1986, the USEPA
               issued an NPDES general permit for discharges from offshore oil and gas facilities conducting exploration,
               development, and production operations on the OCS (51 FR 24897). This general permit established effluent
               limitations, prohibitions, reporting requirements, and other conditions. The USEPA has revised the general
               permit for the Gulf waters excluding the area off Florida, and the proposed permit was published on April 16,
               1991. The USEPA is in the process of responding to comments and expects the final permit to be issued by
               the end of the year. The USEPA, Region IV, which is responsible for the Eastern Gulf, is beginning work on
               their general permit. No dates are available.
                   Proposed new offshore effluent guidelines, which the general permit is based upon, have been published
               in the Federal Register (55 FR 49094, November 26, 1990) for comment. New proposed effluent limitation
               guidelines and standards for drilling muds and cuttings, produced waters, well treatment fluids, produced sands,
               and domestic and sanitary wastes discharges are being considered at this time by USEPA_ These new effluent
               limitation regulations will take into account industry's best available control technology, best conventional
               pollutant control technology, and new source performance standards.           Considering that existing effluent
               limitations have only considered best practicable control technologies, the new discharge limitations and
               standards are expected to significantly alter some existing discharge practices. Promulgation of these effluent
               limitations will occur on June 19, 1992.
                   When injected underground, oil and gas operational wastes are regulated by USEPA!s third program, the
               Underground Injection Control program, established by Part C of the Safe Drinking Water Act (P.L. 93-523,
               as amended by P.L. 99-339 on June 19, 1986).

               Section 404


                   Section 404 of the Federal Water Pollution Control Act has had a substantial effect on areas adjacent to
               navigable waters. This section requires a Corps of Engineers permit for the disposal or emplacement for
               development purposes of dredge or fill material, and for the building of structures in all the waters of the
               United States. Section 404 requires Corps of Engineers approval, with consultation from other Federal and
               State agencies, for the dredging of pipeline canals and navigation routes that service OCS production and
               activities in the coastal areas of the Gulf of Mexico.


               Air Emissions Regulatory Framework

                   The Clean Air Act (CAA) (42 U.S.C. 7401-7642) has been an evolving law, beginning with the Clean Air
               Legislation of 1955, to the 1963 Clean Air Act, and through various amendments in 1967, 1970, 1977, and
               finally 1990. At each step, the CAA gave the Federal government more control over air pollution issues, and
               finally, the amendments in 1977 authorized USEPA to provide for air pollution prevention and control
               activities. The 1990 amendments give the USEPA jurisdiction of OCS air emissions in the Pacific, Arctic,
               Atlantic, and east of 87030' W. longitude in the Gulf of Mexico. The 1990 CAA amendments instruct MMS
               to conduct and complete a study within 3 years of the date of CAA Reauthorization or the effects of offshore
               air emissions on onshore air quality in nonattainment areas for 03 and NO, These areas must be located in
               OCS areas under MMS jurisdiction.
                   The goals of the CAA are specifically (1) to protect and enhance the quality of the Nation's air resources
               so as to promote the public health and welfare and the productive capacity of its population; (2) to initiate and
               accelerate a national research and development program to achieve the prevention and control of air pollution;
               (3) to provide technical and financial assistance to State and local governments in connection with development
               and execution of their air-pollution prevention and control programs; and (4) to encourage and assist the
               development and operation of regional air pollution controls programs. Other important contributions of the
               CAA are the introduction and development of NAAQS; use of the regional approach and introduction of the











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                  prevention of significant deterioration concepts to air quality control; emissions standards for new or modified
                  sources and hazardous pollutants; Federal authority to deal with interstate and intrastate air pollution problems;
                  and the regulatory power to deal with 03-destroying chemicals.
                      The USEPA established ambient air quality standards and regulations. These standards, are the primary
                  and secondary air quality standards used to establish the air quality control of each State. The USEPA has
                  also developed air quality standards for hazardous pollutants. The primary standards are designed to protect
                  public health; secondary standards are designed to protect the public welfare. Other amendments established
                  deadlines for establishing the air quality status and for achieving the reduction and controls necessary of the
                  air quality regions.
                      The Act requires that Federal departments or agencies having jurisdiction over any property, facility, or
                  engaged in any activity resulting in the discharge of air pollutants comply with all Federal, State, interstate, or
                  local requirements in the control and abatement of air pollution. The Act is referred to in Section 5(a)(8) of
                  the OSCLA, which describes DOI's authority to regulate air emissions from OCS oil and gas facilities. The
                  MMS has established 30 CFR 250.44, 250.45, and 250.46 to comply with the Clean Air Act. The MMS also
                  established 30 CFR 250.67 to regulate activities in hydrogen sulfide prone areas. These regulations allow the
                  collection of information about potential sources of pollution for the purpose of preventing accidents and air
                  quality deterioration.

                  Regulations for the Prevention of Pollution by Solid Wastes from Ships

                      The Marine Pollution Research and Control Act of 1987 (Title 11 of P.L. 100-200) implements Annex V
                  of the International Convention for the Prevention of Pollution from Ships. Most of the law's regulatory
                  provisions became effective on December 31, 1988. Under provisions of the law, all ships and watercraft,
                  including all commercial and recreational fishing vessels, are prohibited from dumping plastics at sea. The law
                  also severely restricts the legality of dumping other vessel-generated garbage and solid waste items both at sea
                  and in U.S. navigable waters. The USCG is responsible for enforcing the provisions of this law and has
                  developed final rules for its implementation (55 FR 171, September 4, 1990), calling for adequate trash
                  reception facilities at all ports, docks, marinas, and boat launching facilities.
                      Interim final rules published May 2, 1990 (55 FR 85, pages 18578-18581) explicitly stated that fixed and
                  floating platforms or all drilling rigs, manned production platforms, and support vessels operating under a
                  Federal oil and gas lease (33 CFR 151.73) are required to develop Waste Management Plans (33 CFR 151.57)
                  and to post placards reflecting MARPOL, Annex V dumping restrictions (33 CFR 151.59). Waste Management
                  Plans will require oil and gas operators to describe procedures for collecting, processing, storing, and
                  discharging garbage and to designate the person who is in charge of carrying out the plan. These rules also
                  apply to all oceangoing ships of 40 ft of more in length that are documented under the laws of the U.S. or
                  numbered by a State and that are equipped with a galley and berthing. Placards noting discharge limitations
                  and restrictions, as well as penalties for noncompliance, apply to all boats and ships 26 ft or more in length.
                  Furthermore, the Shore Protection Act of 1988 (FR 22546; May 24, 1989) requires ships transporting garbage
                  and refuse to assure that the garbage and refuse is properly contained on board so that it will not be lost in
                  the water from inclement wind or water conditions.


                  Occupational Safety and Health Act

                      The Occupational Safety and Health Act of 1970 (29 U.S.C. 651-678) was enacted to assure, to the extent
                  possible, every working man and woman in the Nation safe and healthful working conditions and to preserve
                  our human resources. The Act encourages employers and employees in their efforts to reduce occupational
                  safety and health hazards in their places of employment and stimulates the institution of new programs and
                  the perfection of existing programs for providing safe and healthful working conditions. The Act establishes
                  a National Institute for Occupational Safety and Health, which is authorized to develop and establish
                  occupational safety and health standards. Likewise, the Act establishes a National Advisory Committee on
                  Occupational Safety and Health consisting of members appointed by the Secretaries of Labor and Health and











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               Human Services. This committee advises, consults, and makes recommendations to the Secretaries on matters
               of the Act's administration.
                    The Act empowers the Secretary of Labor or his representative to enter any factory, plant, establishment,
               workplace, or environment where work is performed by employees and to inspect and investigate during regular
               working hours and at other reasonable times any such place of employment and all pertinent conditions and
               equipment therein. If, upon inspection, the Secretary or authorized representative believes that an employer
               has violated provisions of the Act, the employer shall be issued a citation and given 15 days to contest the
               citation or proposed assessment of penalty. If the Secretary has reason to believe that an employer has failed
               to correct a violation for which a citation has been issued, the employer shall be notified of such failure and
               of the penalty proposed to be assessed. In addition, the Act provides for any representatives of employees who
               believe that a violation of a safety or health standard exists that threatens physical harm, or that imminent
               danger exists, may request an inspection by giving notice to the Secretary or his authorized representative of
               such a violation or danger.

               Oil Pollution Act of 1990

                    The Oil Pollution Act of 1990, enacted in August 1990, is comprehensive legislation that includes, in part,
               provisions to (1) improve oil-spill prevention, preparedness, and response capability; (2) establish limitations
               on liability for damages resulting from oil pollution; and (3) implement a fund for the payment of compensation
               for such damages.
                    The Off Pollution Act of 1990 amends portions of the Intervention on the High Seas Act, the Federal
               Water Pollution Control Act, the Deepwater Port Act, and the Outer Continental Shelf Lands Act
               Amendments of 1978. Amendments to these Acts provide that all monies remaining in the pollution funds
               established by these Acts and any amounts received through the oil discharge-related provisions of the Federal
               Water Pollution Control Act shall be deposited into the Oil Spill Liability Trust Fund implemented under the
               Oil Pollution Act of 1990. In return, the Oil Spill Liability Trust Fund assumes all liability incurred by the
               Offshore Oil Pollution Compensation Fund, the Deepwater Port Liability Fund, and the revolving Fund set up
               under the Federal Water Pollution Control Act
                    Amounts in the Oil Spill Liability Trust Fund shall also be available for (1) the payment of removal costs
               and other costs as outlined in Section 1012 of the Oil Pollution Act of 1990; (2) carrying out the sections
               relating to oil pollution or the substantial threat of oil pollution in the Intervention on High Seas Act (Sections
               5 and 7); and (3) carrying out subsections (b), (c), (d), 0), and (1) of Section 311 of the Federal Water Pollution
               Control Act with respect to oil discharge-related prevention, removal, and enforcement. The $1 billion
               National Oil Spill Liability Trust Fund will be established from a five-cent-per-barrel tax on all oil. The Fund
               can provide up to $1 billion per incident for cleanup costs and can compensate oil-spill victims when liability
               limits have been reached or if a spiller and an injured party cannot reach an agreement on a settlement within
               60 days. The limit established under the Fund for natural resource damage restoration or replacement is $500
               million.
                    The Act specifies that cargo owners are not liable for spills and raises the liability limits from $150 per
               gross ton to $1,200 per gross ton for vessels. Liability for offshore facilities is set at $75 million plus unlimited
 .4            removal costs, while liability for onshore facilities or a deepwater port is set at $350 million. Willful
               misconduct, violation of any Federal operating or safety standard, failure to report an incident, or refusal to
               participate in a cleanup subjects the spiller to unlimited liability under provisions of the Act.
                    Pursuant to the Act, double hulls are required on all newly constructed tankers. Double hulls or double
               containment systems are required on all tank vessels less than 5,000 gross tons (i.e., barges). Beginning in 1995,
               existing single-huff tankers will be phased out based on size and age. All single-hull tankers will be banned
               after the year 2010.
                    If a discharge or substantial threat of a discharge of oil or a hazardous substance from a vessel, offshore
               facility, or onshore facility is considered to be of such a size or character to be a substantial threat to the public
               health or welfare of the U.S., under provisions of the Act, the President (through the USCG) now has the
               authority to direct all Federal, State, and private actions to remove a discharge or to mitigate or prevent the
               threat of the discharge. Potential impacts from discharges of oil or a hazardous substance to fish, shellfish,










                  1-32


                  wildlife, other natural resources, or the public and private beaches of the U.S. would be an example of the
                  degree or type of threat considered to be of such a size or character to be a substantial threat to the U.S.
                  public health or welfare. In addition, the USCG's authority to investigate marine accidents. involving foreign
                  tankers has been expanded to include accidents in the Exclusive Economic Zone. The Act also establishes
                  USCG oil-spill response groups (to include equipment and personnel) in each of the 10 USCG districts, with
                  a national response unit to be located at Elizabeth City, North Carolina.
                       The Oil Pollution Act of 1990 requires that contingency plans address the response to a "worst case" oil
                  spill or a substantial threat of such a discharge. It also requires that vessels and both onshore and offshore
                  facilities have response plans approved by the President. These plans adhere to specified requirements,
                  including the demonstration that they have contracted with private parties to provide the personnel and
                  equipment necessary to respond to or mitigate a 'worst case" spill. In addition, the Act provides increased
                  penalties for violations of statutes related to oil spills, including payment of triple costs by persons who fail to
                  follow contingency plan requirements.
                       Within 180 days of the enactment of the Act, an Interagency Coordinating Committee on Oil Pollution
                  Research, established by the provisions of the Act, will submit a plan for the implementation of an oil-pollution
                  research, development, and demonstration program to Congress. This program will address, in part, an
                  identification of significant oil-pollution research gaps, an establishment of research priorities and goals, and
                  an estimate of the resources and timetables necessary to accomplish the identified research tasks. The program
                  is required to provide for (1) research, development, and demonstration of new and improved technologies that
                  are effective in preventing or mitigating oil discharges and that will protect the environment; (2) oil-pollution
                  prevention and mitigation technology evaluation; and (3) a research program to monitor and evaluate the
                  environmental effects of oil discharges.

                  (0 Federal Compensation for Damages or Pollution

                  77ze Oil Liability Trust Fund

                       Title III of the Outer Continental Shelf Lands Act Amendments of 1978 has been repealed. Any amounts
                  remaining in the Offshore Oil Pollution Compensation Fund established under Section 302 of that title and any
                  amounts remaining in the revolving fund established under subsection (k) of the Federal Water Pollution
                  Control Act shall be deposited in the Oil Spill Liability Trust Fund pursuant to the Oil Pollution Act of 1990.
                  In addition, any amounts received through the oil discharge-related provisions of the Federal Water Pollution
                  Control Act shall also be deposited into the Oil Spill Liability Trust Fund. In return, the Oil Spill Liability
                  Trust Fund shall assume all liability incurred by the Offshore Oil Pollution Compensation Fund and the
                  revolving Fund set up under the Federal Water Pollution Control Act. Liability incurred by the Deepwater
                  Port Liability Fund will also be assumed by the Oil Spill Liability Trust Fund.
                       In addition to the liability incurred by the Fund, amounts in the Oil Spill Liability Trust Fund shall also
                  be available for (1) the payment of removal costs and other costs as outlined in Section 1012 of the Oil
                  Pollution Act of 1990; (2) carrying out the sections relating to oil pollution or the substantial threat of oil
                  pollution in the Intervention on High Seas Act (Sections 5 and 7); and (3) carrying out subsections (b), (c), (d),
                  0), and (1) of Section 311 of the Federal Water Pollution Control Act with respect to oil discharge-related                      4.
                  prevention, removal, and enforcement.
                       Section 1012 of the Oil Pollution Act of 1990 indicates that the Fund will generally be available to the
                  President for the payment of the following:

                           (1)    removal costs, including the costs of monitoring removal costs, determined by the
                                  President to be consistent with the National Contingency Plan;

                           (2)    costs incurred for assessing natural resource damages and for developing and
                                  implementing plans for the restoration, rehabilitation, replacement, or acquisition of
                                  damaged resources;











                                                                                                                                 1-33


                         (3)    removal costs as a result of, and damages resulting from, a discharge, or a substantial
                                threat of a discharge, of oil from a foreign offshore unit;

                         (4)    uncompensated removal costs; and

                         (5)    Federal administrative, operational, and personnel costs and expenses for the
                                implementation, administration, and enforcement of the Act.

                 Fishermen's Contingency Fund

                     Final regulations for the implementation of Title IV of the OCSLA, as amended (43 U.S.C. 1841-1846),
                 were published in the Federal Register on January 24, 1980 (50 CFR 296). The OCSIA as amended,
                 established the Fishermen's Contingency Fund (not to exceed $2 million) to compensate commercial fishermen
                 for actual and consequential damages including loss of profit due to damage or loss of fishing gear by various
                 materials and items associated with oil and gas exploration, development, or production on the OCS. This
                 Fund, administered by the Financial Services Division of NMFS, mitigates most losses suffered by commercial
                 fishermen due to OCS oil and gas activities.
                     As required in the OCSLA, nine area accounts have been established--five in the Gulf of Mexico, one in
                 the Pacific, one in Alaska, and two in the Atlantic. The five Gulf accounts cover the same areas as the five
                 MMS Gulf OCS Districts. Each area account is initially funded at $100,000 and cannot exceed this amount.
                 The accounts are initiated and maintained by assessing holders of leases, pipeline rights-of-way and easements,
                 and exploration permits. These assessments cannot exceed $5,000 per operator in any calendar year.
                     The claims eligible for compensation are generally contingent upon the following: (1) damages or losses
                 must be suffered by a commercial fisherman; and (2) any actual or consequential damages, including loss of
                 profit, must be due to damages or losses of fishing gear by items or obstructions related to OCS oil and gas
                 activities. Damages or losses that occur in non-OCS waters may be eligible for compensation if the item(s)
                 causing damages or losses are associated with OCS oil and gas activities.
                     Ineligible claims for compensation are generally (1) damages or losses caused by items that are attributable
                 to a financially responsible party-, (2) damages or losses caused by negligence or fault of the commercial
                 fishermen; (3) occurrences before September 18, 1978; (4) claims of damages to, or losses of, fishing gear
                 exceeding the replacement value of the fishing gear; (5) claims for loss of profits in excess of 6 months, unless
                 supported by records of the claimant's profits during the previous 12 months; (6) claims or any portions of
                 damages or losses claimed that will be compensated by insurance; (7) claims not filed within 60 days of the
                 event of the damages or losses; and (8) damages or losses caused by natural obstructions or obstructions
                 unrelated to OCS off and gas activities.
                     There are several requirements for filing claims, including one that a report, stating among other things
                 the location of the obstruction, must be made within 5 days after the event of the damages or losses; this 5-day
                 report is required to gain presumption of causation. A detailed claim form must be filed within 60 days of the
                 event of the damages or losses. The specifics of this claim are contained in 50 CFR 296. The claimant has
                 the burden of establishing all the facts demonstrating eligibility for compensation, including the identity or
                 nature of the item that caused the damages or losses and its association with OCS oil and gas activity.
                     Damages or losses are presumed to be caused by items associated with OCS oil and gas activities provided
                 the claimant establishes that (1) the commercial fishing vessel was being used for commercial fishing and was
                 located in an area affected by OCS oil and gas activities; (2) the 5-day report was filed; (3) there is no record
                 in the most recent NOAA/NOS nautical charts or weekly USCG Notice to Mariners of an obstruction in the
                 immediate vicinity; and (4) no proper surface marker or lighted buoy marked the obstruction. Damages or
                 losses occurring within a one-quarter-mile radius of obstructions recorded on charts, listed in the Notice to
                 Mariners, or properly marked are presumed to involve the recorded obstruction.











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                  National Resource Damage Assessment Regulations

                       Section 301(c) of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980
                  (CERCLA) (42 U.S.C. 9601 et seq.), modified by the 1986 Superfund Amendments and Reauthorization Act
                  (SARA) and Section 1006 of the Oil Pollution Act of 1990, requires the promulgation, of rules for the
                  assessment of damages for, injury to, destruction of, or loss of natural resources resulting from a discharge of
                  oil or a release of a hazardous substance. These assessments are specified for hazardous substance releases
                  in Sections 107(a) and 111(a) and (b) of CERCIA and for a discharge of oil into or upon navigable waters,
                  or upon adjoining shorelines or the exclusive economic zone in Sections 311 (f)(4) and (5) of the Clean Water
                  Act (Section I.B.M.(3)(e)) and Section 1006 of OPA. The natural resource damage assessment requirements
                  provide a process for determining proper compensation to the public for injury to natural resources. Section
                  301(c) of CERCLA specified two types of procedures to be developed: type "A" procedures for simplified
                  assessments requiring minimal field observations and type "B" procedures for individual cases. On August 1,
                  1986, the U.S. Department of the Interior issued final regulations (51 FR 27674) establishing procedures for
                  assessing damages to natural resources to be used by authorized Federal and State officials referred to as
                  "trustees." Type "A" procedures were codified for coastal and marine environments on March 20, 1987 (52 FR
                  9042). On February 22, 1988 (53 FR 5166), the regulations were modified to conform with amendments to
                  CERCIA brought about by the 1986 Superfund Amendments and Reauthorization Act (SARA). Finally, on
                  September 22, 1989, the Department of the Interior announced that it intends to revise the type "A7 natural
                  resource damage assessment procedures in response to recent court rulings (54 FR 39013). On December 28,
                  1990, NOAA published an advanced notice of proposed rulemaking to establish its own procedures for natural
                  resource damage assessment under OPA-
                  4. Interrelationship with Other Federal Policies Governing OCS
                       Environmental Resources

                  a. Ports and Waterways Safety Act

                       The Ports and Waterways Safety Act (33 U.S.C. 1221-1232) promotes the safety of ports, harbors,
                  waterfront areas, and navigable waters of the United States. The Act was amended by the Ports and Tanker
                  Safety Act (92 Stat. 1471) in 1978 to expand the authority of the Act to the protection of navigation and vessel
                  safety and to the protection of the marine environment.
                       The Act authorizes increased supervision of vessel and port operations to reduce vessel or cargo loss; to
                  prevent damage to life, property, or the marine environment; and to prevent damage to structures in, on, or
                  immediately adjacent to navigable waters of the United States or the resources within such waters. It also
                  requires that the Secretary of Transportation ensure that vessels operating in U.S. navigable waters comply with
                  all applicable standards and requirements for vessel construction, equipment, manning and operational
                  procedures, and that the handling of dangerous articles and substances within navigable waters be conducted
                  within established standards and requirements.
                       The Act authorizes the Coast Guard to designate necessary safety fairways and traffic separation schemes
                  (TSS's) to allow vessels unobstructed, safe access to U.S. ports. Safety fairways are areas in which no fixed
                  structures are permitted and, therefore, may inhibit exploration and exploitation of mineral resources in the
                  designated areas. Fairways may be viewed as a necessary compromise between convenient mineral exploitation
                  and concern for navigation safety. The TSS's are designed to increase navigation safety by separating opposing
                  lanes of vessel traffic. In order to ensure that the interests of all affected parties are considered, the Act
                  mandates that a port access route study be conducted when new fairway areas or TSS's are contemplated.
                  Publication of a study notice advises all bidders in future lease sales within the study area that occupancy rights
                  may be restricted by a routing system developed as a result of the study. The USCG must also consult with
                  DOI to reconcile the need for safe access routes with the needs of all other reasonable uses of the area
                  involved. Lessees are advised that the USCG may designate necessary fairways through leased blocks.











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                b. Archaeological Resources Legislation

                    The Federal Government's involvement in archaeological resource management and protection on the OCS
                is based on the requirements of the National Historic Preservation Act of 1966, as amended. This Act states,
                in effect, that any Federal agency, before approving federally permitted or federally funded undertakings, must
                take into consideration the effect of that undertaking on any property listed on, or eligible for, the National
                Register of Historic Places. Implied in this legislation and Executive Order 11593 is that an effort be made
                to locate such sites before development of an area. Section 101(b)(4) of NEPA states that it is the continuing
                responsibility of the Federal Government to preserve important historic and cultural aspects of our natural
                heritage. In addition, Section 11(g)(3) of the OCSLA, as amended, states that "such exploration (oil and gas)
                will not ... disturb any site, structure, or object of historical or archaeological significance."

                c. Endangered Species Act of 1973

                    The Endangered Species Act of 1973 (16 U.S.C. 1531-1543), as amended, establishes a national policy
                designed to protect and conserve threatened and endangered species and the ecosystem upon which they
                depend. The Act is administered by FWS and NMFS. Section 7 of the Act governs interagency cooperation
                and consultation. The MMS formally consults with NMFS and FWS because there is a possibility that activities
                in support of a proposed action may constitute a take as defined under the Endangered Species Act. The
                agencies, FWS and NMFS, must determine and ensure that proposed actions are unlikely to jeopardize the
                continued existence of a threatened or endangered species and/or to result in adverse modification or
                destruction of their critical habitat The results of these determinations are presented as Biological Opinions
                (Appendix B). If it is determined that taking has occurred, a reinitiation of formal consultation could be
                required.
                    The FWS makes recommendations on the modification of oil and gas operations to minimize adverse
                impacts. The MMS has enacted the following FWS recommendations:

                        (1)     require adequate oil spill contingency plans for all activities; and

                         (2)    urge aircraft supporting offshore facilities to maintain an altitude of 2,000 ft or more
                                above national parks, seashores, and wildlife refuges.

                    The MMS Studies Program complies with the Act's intent of conserving endangered or threatened species
                by contracting research on marine turtles and cetaceans. Data derived from these studies supplement
                information in the biological opinions and identify potential conflicts with oil and gas development.

                d. Marine Mammal Protection Act of 1972


                    The Marine Mammal Protection Act (MMPA) of 1972 (16 U.S.C. 1361 et seq.), as amended, establishes
                a national policy designed to protect and conserve marine mammals and their habitats. This policy is
                established so as not to diminish such species or population stocks beyond the point at which they cease to be
                a significant, functioning element in the ecosystem, nor to diminish such species below their optimum
                sustainable population. The Secretaries of Commerce and the Interior have delegated authority for
                administering the Act to NMFS, which is responsible for all cetacean and pinnipeds (except walruses), and to
                FWS, which is responsible for walruses, sea otters, manatees, and dugongs.
                    The Marine Mammal Commission and its delegated administrators are responsible for reviewing and
                advising Federal agencies for the protection and conservation of marine mammals because activities under the
                authority of Federal agencies may constitute a take as defined under the MMPA- If it is ascertained that taking
                may occur, an exemption to or waiver of the Act's moratorium on taking would be required from the
                responsible parties. The Act provides particular exemptions to the taking of marine mammals by Alaskan
                natives under certain conditions. The Act authorizes the Commission to make recommendations on the










                  1-36


                  prohibition of the taking and importation of marine mammals and marine mammal products, except as
                  expressly provided for by an international treaty, convention, or agreement to which the United States is a
                  party.
                      In late March 1991, The American Petroleum Institute (API), representing all operators in the Gulf of
                  Mexico, requested a rulemaking from NMFS concerning "a small take of spotted and bottlenose dolphins
                  incidental to the removal of off and gas drilling and production structures in state and on the Outer Continental
                  Shelf in the Gulf of Mexico (GOM) over the next five years." The API estimated that 134 structures per year
                  will be removed from the Gulf of Mexico during the next 5 years and that 5,500 structureswiff be removed by
                  the year 2026. About 80 percent of wells and platform legs are expected to be severed using explosives. Since
                  1986, MMS, the U.S. Army Corp of Engineers, and removal operators have been following strict NMFS
                  recommendations to avoid adverse impacts to endangered marine turtles and cetaceans.                         These
                  recommendations have also been followed to avoid the incidental taking of marine mamma Is, endangered or
                  not. In their request for rulemaking, API stated that the most likely form of incidental take of dolphinids as
                  a result of structure removals is harassment from low-level sound and pressure waves.
                      Pursuant to 50 CFR 228, NMFS asked for comments, information, and suggestions concerning API's
                  request and concerning the structure and content of their (NMFS) forthcoming regulations to allow the
                  incidental taking of dolphinids during platform removals. This input has been received and NMFS must now
                  develop an environmental assessment. If, in the environmental assessment, the Secretary of Commerce finds
                  that the total taking will have a "negligible impact" on the species or stock and not have an "unmitigable
                  adverse impact" on the availability of the species or stock for subsistence use, then, upon request, the incidental
                  taking of small numbers of dolphinids will be allowed during platform removals. The Secretary's permission
                  for this incidental take may be granted for periods of 5 years or less. After these final regulations are
                  established, Letters of Authorization must be requested from and issued to individual applicants (operators)
                  to conduct the activities (platform removals) pursuant to the regulations.
                      The MMS commented to NMFS on the request and sent an advanced copy of excerpts from an MMS-
                  funded research effort titled Undenvater Blast Effects firom Explosive Severance of Platform Legs and Well
                  Conductors (Connor, 1990). The research was performed by the Naval Surface Warfare Center (NAVSWC).
                  The in situ data strongly indicate that any negative pressure events occurring as a result of explosive severance
                  activities present a much lower risk than originally anticipated. The potential energy released to the open-water
                  environment is greatly attenuated by the structures being severed and from the location of detonation below
                  the mudline. The NAVSWC research used an explosive called pentolite, which is not used in the Gulf of
                  Mexico because it is a slow velocity explosive and does not have the cutting power needed to severe most Gulf
                  of Mexico platform legs. However, a slow velocity explosive such as pentolite has a greater adverse effect upon
                  marine mammals, turtles, and fish than the explosives (Composition B and Composition 4) used in the Gulf
                  of Mexico during platform removals (Connor, 1990; Crawford, personal comm., 1991).
                    A provision of the Marine Mammal Protection Act (under Section 101 (a) (3), 16 U.S.C. 1371 et seq.)
                  directs the Secretary of Commerce to allow, on request, those engaged in oil and gas activities from the "taking"
                  prohibitions stated within the Act when the taking is unintentional, involves small numbers of individuals, and
                  has negligible effects, provided that satisfactory provisions have been made to monitor and report the taking.
                  To ensure that OCS activities adhere to regulations stated within Section 101 (a) (3), MMS must actively seek
                  to gain information concerning local species of marine mammals in relation to impacts from OCS activities.
                  Likewise, a requirement of the Outer Continental Shelf Lands Act (Section 20) states that the Secretary shall
                  conduct studies subsequent to the leasing and development of any area or region to establish environmental
                  monitoring information designed to provide time-series and data trend information that can be used for
                  comparison with existing historical data for the purpose of identifying significant changes, if any, in such issues
                  as the distribution, abundance, breeding habits, and times and lines of migratory movements of marine
                  mammals. Consequently, the MMS Outer Continental Shelf Environmental Studies Program has recently (1991)
                  funded a series of studies through Texas A&M University on the distribution and abundance of marine
                  mammals in the north-central and Western Gulf of Mexico designed to produce a first-step estimate of the
                  potential effects of deep-water exploration and production on these species. The studies include systematic
                  aerial and shipboard surveys, behavioral observations, and the tagging and subsequent tracking of a limited
                  number of sperm whales using satellite telemetry. Data acquired from both shipboard surveys and remote











                                                                                                                                     1-37

               sensing will be used to characterize preferred habitats of cetaceans in the study area, whereas data acquired
               from behavioral observations will be used to determine preferred geographic areas and temporal patterns of
               critical activities such as feeding, breeding, and mating.
               e. Magnuson Fishery Conservation and Management Act of 1976

                    The Magnuson Fishery Conservation and Management Act of 1976 (MFCMA) (16 U.S.C. 1801-1882)
               established a fisheries conservation zone for the United States and its possessions and delineates an area from
               the States' seaward boundary out 200 nmi. The Act created eight Regional Fishery Management Councils
               (FMC's) and mandated a continuing planning program for marine fisheries management by the Councils. The
               Act, as amended, requires that a Fishery Management Plan (IMP) based upon the best available scientific and
               economic data be prepared for each commercial species (or related group of species) of fish that is in need
               of conservation and management within each respective region.
                   Based on Congressional direction, the MFCMA must be reauthorized every few years. At the time of
               reauthorization, Congress also considers amendments to the Act that will update and improve the fishery
               management system. The individual FMC's also take part in the process by recommending changes to the Act
               that they believe are necessary to improve the fishery management system. During the 1989 consideration of
               reauthorization, the Gulf of Mexico FMC recommended 14 amendments, many of which addressed budgeting,
               funding, administrative, and data-gathering concerns. The important fishery recommendations from the Gulf
               of Mexico FMC were amendments to include tuna, billfish, and sharks under the MFCMA. Tuna were
               excluded under Section 102 because they are a highly migratory species; however, landings for tuna have
               increased exponentially in the Gulf during the past 5 years. The Gulf of Mexico FMC believes tuna are in need
               of a management plan but cannot manage the species until it is included under the Act
                  To date, nine FMP's have been implemented. The FMP for shrimp was implemented in 1981; for stone
               crab, in 1982; for spiny lobster, in 1982; for coastal pelagic fish, in 1983; for coral, in 1984; for reef fish, in 1984;
               for swordfish, in 1985; for red drum, in 1987; and for sharks, in 1991. The FMP's are amended and updated
               as new information from studies and public input is received and assessed.
                  Congress has reauthorized the MFCMA with some changes. Tuna, swordfish, sharks, and billfish are now
               included for protection under the MFCMA. Responsibility for their management and conservation has been
               given to the appropriate FMC's through the NMFS.

               f. National Fishing Enhancement Act of 1984

                   Title 11 of Public Law 98-623, also known as the Artificial Reef Act, establishes broad artificial-reef
               development standards and a National policy of the United States to encourage the development of artificial
               reefs that will enhance fishery resources and commercial and recreational fishing. The Secretary of Commerce
               provided leadership in developing a National Artificial Reef Plan that identifies design, construction, siting, and
               maintenance criteria for artificial reefs and that provides a synopsis of existing information and future research
               needs. The Secretary of the Army issues permits to responsible applicants for reef development projects in
               accordance with the National Plan, as well as regional, State, and local criteria and plans. The law also limits
               the liability of reef developers complying with permit requirements and amends the Reefs for Marine Life
               Conservation Law to include the availability of all surplus Federal ships for consideration as reef development
               materials. Although the Act mentions no specific materials other than ships for use in reef development
               projects, the Secretary of the Interior cooperated with the Secretary of Commerce in developing the National
               Plan, which identifies oil and gas structures as acceptable materials of opportunity for artificial-reef
               development. The MMS adopted a Rigs-to-Reefs policy in 1985 in response to this Act and to broaden
               interest in the use of petroleum platforms as artificial reefs.

               g. Executive Order 11990 (May 24, 1977), Protection of Wetlands

                  This Executive Order is pertinent to the proposed actions as it states in part:










                   1-38

                             Each agency shall provide leadership and shall take action to minimize the destruction, loss
                             or degradation of wetlands, and to preserve and enhance the natural and beneficial values
                             of wetlands in carrying out the agency's responsibilities for: (1) acquiring, managing, and
                             disposing of Federal lands and facilities; (2) providing federally undertaken, financed, or
                             assisted construction and improvements; and (3) conducting Federal activities and
                             programs affecting land use, including but not limited to water and related land resources
                             planning, regulating, and licensing activities.

                   h. Marine and Estuarine Sanctuaries Legislation

                       The National Marine Sanctuary and National Estuarine Research Reserve programs are administered by
                   the Sanctuaries and Reserves Division, National Ocean Service, National Oceanic and Atmospheric
                   Administration of the U.S. Department of Commerce. The marine sanctuary program was established by the
                   Marine Protection, Research, and Sanctuaries Act of 1972 (33 U.S.C. 1401-1445), and the estuarine research
                   reserve program was established by the Coastal Zone Management Act of 1972.
                       Marine sanctuaries and estuarine research reserves are designed and managed to meet the following goals,
                   among others:

                            (1)    enhance resource protection through the implementation of a comprehensive, long-
                                   term management plan tailored to the specific resources;

                            (2)    promote and coordinate research to expand scientific knowledge of significant marine
                                   resources and improve management decisionmaking;

                            (3)    enhance public awareness, understanding, and wise use of the marine environment
                                   through public interpretive and recreational programs; and

                            (4)    provide for optimum compatible public and private use of special marine areas.

                   Marine Sanctuaries

                       Title III of the Marine Protection Research and Sanctuaries Act pertains to national marine sanctuaries.
                   Only sites with special national significance are selected for marine sanctuary status. Sites selected for
                   consideration are evaluated on the merits of resource and human-use values and on the public benefits to be
                   derived from sanctuary status.
                       One national marine sanctuary has been established in the Gulf of Mexico by a recent act (H.R. 5909;
                   P.L. 101-605) of Congress: the Florida Keys National Marine Sanctuary. Another, the Flower Garden Banks
                   National Marine Sanctuary was designated in December 1991 and become effective in early 1992.
                       Florida Keys National Marine Sanctuary: Just offshore the Florida Keys land mass are, to quote H.R. 5909,
                    ... spectacular, unique, and nationally significant marine environments, including seagrass meadows, mangrove
                   islands, and extensive living coral reefs ... These marine environments support rich biological communities
                   possessing extensive conservation, recreational, commercial, ecological, historical, research, educational, and
                   esthetic values which give this area special national significance. . . These environments... support high levels
                   of biological diversity, are fragile and easily susceptible to damage from human activities, and possess high value
                   to human beings if properly conserved . . . (and) are subject to damage and loss of their ecological integrity
                   from a variety of sources of disturbance ... (including) vessel groundings ... Action is necessary to provide
                   comprehensive protection for these marine environments ... by restricting vessel traffic . . . and by requiring
                   promulgation of a management plan and regulations to protect sanctuary resources."
                       This new law is designated to protect the resources of the area, to educate and interpret the environment,
                   and to manage human uses within the Sanctuary. The area of the Sanctuary would include essentially all











                                                                                                                                1-39


               submerged lands and waters, including living marine and other resources, from the mean high-water mark of
               the Keys out to the 300-ft isobath, excluding Fort Jefferson National Monument.
                    The following two uses of the area are specifically prohibited by the law. (1) operation of a tank vessel
               or a vessel greater than 50 in in length, except for public vessels; and (2) leasing, exploration, development,
               or production of minerals or hydrocarbons.
                    An advisory council has also been established to assist in the development of a comprehensive management
               plan and in the implementation of regulations. The Secretary of Commerce is directed to consult with other
               Federal agencies and the appropriate State and local governments in managing the Sanctuary. The Sanctuary
               incorporates the existing Lom Key and Key Largo National Marine Sanctuaries on the Atlantic side of the
               Keys. An EIS will be prepared, as has been done in all previous sanctuary designations. Sombrero Key and
               Alligator Reef, both of which had previously been mandated for study as marine sanctuaries by Congress, Will
               also be included in the comprehensive management plan.
                    Flower Garden Banks National Marine Sanctuary: One site is well along the road to sanctuary designation.
               The Flower Garden Banks were named an Active Candidate for designation as a national marine sanctuary
               (49 FR 30988-30991) on August 2, 1984, and was designated a sanctuary in December 1991 (56 FR 63634-
               63648). This site, located 177 kin (110 mi) offshore, represents the northernmost coral reef community in the
               Western Gulf of Mexico. The proposed borders of the sanctuary encompass a total of 114 kM2 (44 mi2). The
               area is a valuable representation of a tropical coral reef community dominated by hermatypic coral (Montastrea
               annularis, M cavernosa, Porites asteroides, and Diploria strigosa) and associated reef fishes and invertebrates.
               The DOI has protected the biological resources of the Flower Garden Banks from possible damage due to oil
               and gas exploration and development activities by the establishment of a "No Activity Zone" and by operational
               restrictions as described in the Topographic Features Stipulation (Section IV.13.2.a.(2)(b)). The DOI cannot,
               however, protect these reefs from damage due to activities outside DOI's permitting process. The Gulf of
               Mexico Fishery Management Council, in its proposed FMP for corals, has designated the area within the 50-
               fathom (91.4-m) isobath at the Flower Garden Banks as a Habitat Area of Particular Concern (HAPC) (50
               CFR 638), but even with such designation the Council may be unable to regulate "nonfishing" activities such
               as anchoring of ships. Designation of the reefs as a marine sanctuary may be the only way to protect the reefs
               from non-oil- and gas-related activities, such as anchoring (which has been shown to be the most destructive
               of man's activities in the area), the use of heavy trawls (such as roller trawls), and the taking of corals and reef
               fishes. The following activities, while not necessarily proposed to be regulated initially, may be regulated by
               NOAA under the terms of designation at some future time:

                        (1)    anchoring or otherwise mooring within the Sanctuary,

                        (2)    discharging or depositing, from within the boundaries of the Sanctuary, any material or
                               other matter;

                        (3)    discharging or depositing, from beyond the boundaries of the Sanctuary, any material
                               or other matter;

                        (4)    drilling into, dredging, or otherwise altering the seabed of the Sanctuary, or
                               constructing, placing, or abandoning any structure, material, or other matter on the
                               seabed of the Sanctuary;

                        (5)    exploring for, developing, or producing oil, gas, or minerals within the Sanctuary;

                        (6)    taking, removing, catching, collecting, harvesting, feeding, injuring, destroying, or
                               causing the loss of, or attempting to take, remove, catch, collect, harvest, feed, injure,
                               destroy, or cause the loss of a Sanctuary resource;










                  1-40


                           (7)    possessing within the Sanctuary a Sanctuary resource or any other resource, regardless
                                  of where taken, removed, caught, collected, or harvested, that, if it had been found
                                  within the Sanctuary, would be a Sanctuary resource;

                           (8)    possessing or using within the Sanctuary any fishing gear, device, equipment, or means;

                           (9)    possessing or using explosives or air guns or releasing electrical charges within the
                                  Sanctuary; and

                           (10)   interfering with, obstructing, delaying, or preventing an investigation, search, seizure,
                                  or disposition of seized property in connection with enforcement of Sanctuary
                                  regulations or permits.

                       It should be noted that oil and gas activities regulated by MMS in those small areas of the Sanctuary that
                  are outside the MMS No Activity Zones are specifically excluded from Sanctuary restrictions on oil and gas
                  industry activities.
                     Three additional sites in the Gulf are on the Site Evaluation List (SEL), which potentially leads to an area
                  being designated as an Active Candidate. These sites are Shoalwater Bay--Chandeleur Sound (Louisiana)--the
                  Big Bend Seagrass Beds off Florida, and Baffin Bay (Texas). Areas on the SEL are given additional study for
                  potential designation as an Active Candidate; such designation will then result in even further evaluation for
                  possible designation as a national marine sanctuary. No schedule has been established for these studies and
                       ible designations.
                  possi


                  Estuarine Research Reserves


                     . Three estuarine research reserves have been established in the Gulf of Mexico: Rookery Bay National
                  Estuarine Research Reserve and Apalachicola National Estuarine Research Reserve in Florida, and Weeks
                  Bay National Estuarine Research Reserve in Alabama.
                       Rookery Bay National Estuarine Research Reserve, at more than 3,440 ha (8,500 ac)., preserves a large
                  mangrove-filled bay and two creeks, along with their drainage corridors. Management of the sanctuary is
                  performed by the Florida Department of Natural Resources, The Conservancy, and the National Audubon
                  Society. This unique management structure was created when the two private organizations granted a dollar-
                  per-year, 99-year lease of the land to the State. Federal and State funds will add additional key acreage to the
                  existing core area. The diversity of the area's fauna can be recognized by the porpoises that feed there and
                  the bald eagles and whitetailed deer that make Rookery Bay their permanent residence. Within the Sanctuary
                  is a marine laboratory, which, even before the establishment of the sanctuary, provided data. used in important
                  coastal management decisions--a primary objective of Congress in establishing the estuarine research-reserve
                  program.
                       At more than 76,890 ha (190,000 ac), the Apalachicola National Estuarine Research Reserve is one of the
                  largest remaining naturally functioning ecosystems in the nation, and it is also the first sanctuary on the mouth
                  of a major navigable river. Because of this, its establishment served to promote improved cooperation
                  concerning river navigation among the States of Florida, Alabama, and Georgia. The major business activity
                  of Apalachicola, which is adjacent to the sanctuary, centers around the oyster industry, and it is expected that
                  the sanctuary will benefit this and other fishing industries by protecting the environment and by providing
                  research information that will help assure the continued productivity of the bay/river ecosystem. A FWS refuge
                  and a State park, which represents a unique cooperative effort at ecosystem protection, exists with the
                  boundaries of the reserve.
                       Weeks Bay National Estuarine Research Reserve constitutes a small estuary of approximately 1,225 ha.
                  (3,028 ac), comprising open shallow waters with an average depth of less than 1.5 in (fl ft) and extensive
                  vegetated wetlands areas. It receives waters from the spring-fed Fish and Magnolia Rivers and connects
                  through a narrow opening with Mobile Bay, the principal element of coastal Alabama.
                       There are no additional sites proposed as National Estuarine Research Reserves in the Gulf of Mexico.











                                                                                                                                1-41

                   Title I of the Marine Protection, Research, and Sanctuaries Act is administered by USEPA. Section 102
               of the Act provides that USEPA may issue permits, after public notices and hearings, for the transportation
               of material for the purpose of dumping into ocean waters, after a determination that such dumping will not
               unreasonably degrade or endanger human health, welfare, or the marine environment.

               77te National Estuaiy Program

                   In 1987 the National Estuary Program was established by an amendment, known as the Water Quality Act
               (P.L. 1004, which, among other things, created Section 320), to the Clean Water ACt. The purpose of the
               Program is to identify nationally significant estuaries, to protect and improve their water quality, and to enhance
               their living resources. Under the Program, which is administered by the USEPA, comprehensive management
               plans are generated to protect and enhance environmental resources. The governor of a state may nominate
               an estuary for the Program and request that a Comprehensive Conservation and Management Plan be
               developed for an estuary. Representatives from Federal, State, and interstate agencies, academic and scientific
               institutions, and industry and citizen groups work during a 5-year period to define objectives for protecting the
               estuary, to select the chief problems to be addressed in the Plan, and to ratify a pollution control and resource
               management strategy to meet each objective. Strong public support and subsequent political commitments are
               needed to accomplish the actions called for in the Plan, hence the 5-year time period to develop the strategies.
               A total of 17 estuaries have been selected for the Program, 4 of which are in the Gulf. Sarasota Bay and
               Tampa Bay in Florida, the Barataria-Terrebonne Estuarine Complex in Louisiana, and Galveston Bay in Texas.
               Brief descriptions of these four areas are given below.
                   Sarasota Bay is a small estuary on the southwest coast of Florida. Although generally regarded as a "clean"
               bay, it is threatened by overuse and growth pressure. Stormwater runoff and habitat loss have been identified
               as primary issues of concern in the restoration and enhancement of the estuary. Seven goals have been
               identified as targets upon which to focus the attention of all interested parties. Demonstration projects to begin
               the restoration of native, productive habitat to the bay system have been started, and these and others will be
               an integral part of the final comprehensive plan for the bay.
                   Tampa Bay is the largest open-water estuary in Florida and supports a myriad of uses, such as commercial
               and recreational fishing, shipping, sanitary and electrical services, waterfront development, tourism, and
               recreation. The water quality is good to excellent in much of the lower and middle Bay, declining in old Tampa
               Bay, and undesirable in the Hillsborough area. A number of causes of degradation have been identified, and
               goals have been established to improve the situation.
                   The Barataria-Terrebonne Estuarine Complex consists of an extensive array of estuarine wetlands and
               bodies of water containing more coastal wetlands than any other estuarine system in the United States. At
               least 19 percent of the nation's estuary-dependent commercial fisheries is sustained by the Complex. It is also
               used for recreation by boaters, fishermen, and hunters, supporting important elements of the local economy
               and culture. As much as half of the national loss of coastal wetlands may have occurred in the Complex.
               Problems have been identified, and goals have been established to improve the situation.
                   The Galveston Bay system is the seventh largest estuary in the U.S. and the largest in Texas. The bay
               system provides 1,554 kM2    (600 mi2) of very shallow water, averaging less than 3 in (10 ft) in depth. On the
               average, precipitation in the bay area watershed equals or exceeds what is lost through evaporation, and nearly
               10 million ac-ft of freshwater enter the bay annually. The resulting low salinity in the bay is the key to its
               productivity, providing ideal conditions for the growth of fish, crabs, shrimps, and oysters. In addition, the bay
               is surrounded by 526 km2 (203    Mi2) of estuarine marsh, 36 kM2   (14 Mi2) of forested wetlands, and 158 kM2     (61
               mi2) of freshwater ponds and lakes. These ecological resources filter runoff to the bay system and provide a
               rich source of nutrients that enhance biological productivity, as well as providing valuable habitat for many
               economically important species. The committees set up under the program will identify the critical issues facing
               Galveston Bay and then develop specific action plans and commitments to solve the problems identified.










                  142

                  i. Ocean Dumping

                      All ocean dumping is regulated by the Marine Protection, Research, and Sanctuaries Act of 1972, as
                  amended (33 U.S.C. 1401 et seq.). Regulations (40 CFR 220 et seq.) implementing the Act require a USEPA
                  permit for all ocean dumping of industrial wastes and municipal sludge materials. The termination of ocean
                  dumping of sewage sludge and industrial wastes by December 31, 1981, was mandated by 33 U.S.C. 1412a.
                  The designated ocean areas where wastes may be disposed are listed in 40 CFR 228. Further, USEPA has
                  published an annual report entitled Ocean Dumping in the United States. This report includes information on
                  permit holders, types of waste approved for disposal under the permit, and yearly waste volumes disposed.
                  The USEPA had one designated deep-water disposal area in the Gulf of Mexico. The site was designated for
                  the incineration of hazardous wastes, but the disposal area was officially de-designated on February 27, 1991
                  (56 FR 8133-8135).
                      The current interim-designated Dredged Material Disposal Sites are now being converted by the USEPA
                  into formally-designated sites. These sites, used for the disposal of dredged material from the U.S. Army Corps
                  of Engineers channel dredging programs, have, in most cases, been used for this purpose for as long as 25
                  years.

                  j. Rivers and Harbors Act of 1899

                      Section 10 of the Rivers and Harbors Act of 1899 prohibits the unauthorized obstruction or alteration of
                  any navigable water of the United States. The construction of any structure in or over any navigable water of
                  the United States, the excavating from or depositing of material in such waters, or the accomplishment of any
                  other work affecting the course, location, condition, or capacity of such waters is unlawful without prior
                  approval from the Corps of Engineers. The authority of this legislation to prevent obstructions to navigation
                  in navigable water was extended to installations and devices located on the seabed to the seaward limit of the
                  OCS by Section 4(e) of the Outer Continental Shelf Lands Act of 1953, as amended.

                  k Coastal Barrier Resources Act of 1982

                      The Coastal Barriers Resources Act (CBRA) was the culmination of several years of study by the Congress
                  and the Department of the Interior of the effects of Federal programs on coastal barriers. The Act established
                  186 coastal barrier units that were included in a Coastal Barrier Resource System (CBRS).
                      The CBRA prohibited all new Federal expenditures and financial assistance within the CBRS, with certain
                  specific exceptions including energy development. The purpose of this legislation was to end the Federal
                  Government's encouragement for development on barrier islands by withholding Federal flood insurance for
                  new construction of or substantial improvements to structures on undeveloped coastal barriers.

                  1. National Ocean Pollution Planning Act of 1978

                      The National Ocean Pollution Act of 1978 (33 U.S.C. 1701-1709) calls for the establishment of a
                  comprehensive, coordinated, and effective ocean pollution research, development, and monitoring program.
                  The Act requires that the Department of Commerce's National Oceanic and Atmospheric Administration, in
                  consultation with other agencies, prepare a comprehensive 5-year Federal Plan for Ocean Pollution Research
                  Developmen4 and Monitoring every three years. The Plan contains major elements that consider an assessment
                  and prioritization of National needs and problems, existing Federal capabilities, policy recommendations, and
                  a budget review.

                  m. Coastal Zone Management Act of 1972

                      The Coastal Zone Management Act (CZMA) (16 U.S.C. 1451 et seq.) was enacted by Congress in 1972
                  to improve the nation's management of coastal resources, which were being irretrievably damaged or lost due
                  to poorly planned development. Specific concerns were the loss of living marine resources and wildlife habitat,










                                                                                                                               1-43

                decreasing open space for public use, and shoreline erosion. Congress also recognized the need to resolve
                conflicts between various uses that were competing for coastal lands and waters (USDOC, NOAA, 1988a).
                    The basic goal of the CZMA is to encourage and assist coastal states to voluntarily develop comprehensive
                management programs. The CZMA establishes a State-Federal partnership in which the States take the lead
                in managing their coastal resources, while the Federal Government provides financial and technical assistance
                and agrees to act in a manner consistent with the federally-approved State management programs. The law
                also establishes a National Estuarine Reserve Research System with specific estuarine sites designated across
                the nation. The CZMA is implemented by the Office of Ocean and Coastal Resource Management (OCRM),
                within NOAA!s National Ocean Service.
                    The Coastal Zone Reauthorization Amendments of 1990 amended the Federal consistency provisions to
                counter the Supreme Court's 1984 decision in Secretary of the Interior v. California. This clarified that all
                Federal agency activities, whether in or outside of the coastal zone, are subject to the consistency requirements
                of Section 307(c)(1) of the CZMA if the activities affect natural resources, land uses, or water uses in the
                coastal zone. The purpose of the reauthorization was to strengthen and revitalize the CZMA, particularly in
                the area of water quality.
                    The Coastal Zone Reauthorization Amendments of 1990 established a Coastal Zone Management Fund
                consisting of Coastal Energy Impact Program (CEIP) loan repayments from which the Secretary shall pay for
                the Federal administrative costs of the program and for funding special projects, emergency State assistance,
                and other discretionary coastal zone management activities.
                    The Act also reinstated program development grants by authorizing the Secretary of Commerce to provide
                assistance and managcment-orientcd research to a State for the development and implementation of a CZM
                program.
                    The new provisions encourage each State, under a Coastal Zone Enhancement Grants Program at Section
                309, to improve continually its CZM program in one or more of eight identified national priority areas: coastal
                wetlands management and protection, natural hazards management (including potential sea and Great Lakes
                level rise), public access improvements, reduction of marine debris, assessment of cumulative and secondary
                impacts of coastal growth and development, special area management planning, ocean resource planning, and
                siting of coastal energy and Government facilities. Three new program approval requirements were also added
                at Section 306(d)(14), (15), and (16), dealing with public participation in permitting processes; consistency
                determinations, providing a mechanism to ensure that all State agencies will adhere to the program; and
                requiring enforceable policies and mechanisms to implement the applicable requirements of the new Coastal
                Nonpoint Pollution Control Programs, respectively.
                    The provisions also authorize the Secretary to make annual "Walter B. Jones" achievement awards to
                recognize individuals, local governments, and graduate students for outstanding accomplishments in the field
                of coastal zone management; and the provisions authorize appropriations for five years at increased levels.
                    In addition, the subtitle establishes a Coastal Nonpoint Pollution Control Program at Section 306. This
                program will require each coastal state to develop a program that will protect coastal waters from nonpoint
                pollution from adjacent coastal land uses and will be implemented through the Coastal Zone Management
                Act and Section 319 of the Clean Water Act by NOAA and USEPA_ The NOAA is not proposing to issue
                regulations on the CZM fund, the technical assistance program, the CZM achievement awards, or the Federal
                consistency regulations at this time. Changes to the Federal consistency provisions resulting from CZMA
                Reauthorization, except for overturning the Supreme Court's decision on OCS oil and gas lease sales, merely
                codify NOAXs existing regulations (USDOC, NOAA, 1991). Because of the substantial scope of CZMA
                changes, NOAA will undertake phased rulemaking for Coastal Zone Enhancement Grants, nonpoint pollution
                control programs, new program approval requirements in Section 306, and changes to the National Estuarine
                Research Reserve System (Section 315 of CZMA). On October 18, 1991, the first phase of proposed
                rulemaking was published in the Federal Register (56 FR 52220-52230) to implement the new Coastal Zone
                Enhancement Grants Program (new Section 309), revised procedures for conducting reviews of performance
                under Section 312, and new authority for interim sanctions under Section 312(c).










                  144

                  5. Gulf of Mexico Regional Environmental Studies Program

                      The MMS supports and administers a large, multidisciplinary studies program to develop information
                  needed for assessment and mitigation of impacts to human, marine, and coastal environments that may be
                  affected by OCS off and gas activities. This program was initiated in 1973 by the Bureau of Land Management
                  (BLM), which then had responsibility for OCS leasing. Since program initiation, more than 150 studies
                  projects, at a cumulative funding level in excess of $102 million, have been awarded to support leasing and
                  regulatory functions of the Minerals Management Service's OCS Program within the Gulf of Mexico OCS
                  Region.
                      The MMS Environmental Studies Program (ESP) is authorized by the OCS Lands Act Amendments of
                  1978. Section 20 of the Act mandates the program and provides three general goah;: (a) to establish
                  information needed for assessment and management of environmental impacts on the human, marine, and
                  coastal environments of the OCS and the potentially affected coastal areas; (b) to predict impacts on the
                  marine biota, which may result from chronic low-level pollution or large spills associated with OCS production,
                  from muds and cuttings discharges, pipeline emplacement, and impacts of onshore development; and (c) to
                  monitor human, marine, and coastal environments to provide time-series and data-trend information for
                  identification of significant changes in the quality and productivity of these environments, for detection of
                  change trends, and for identification of the causes of these changes.
                      Appendix E of the Final EIS for Sales 131, 135, and 137 (USDOI, MMS, 1990a) provides detailed
                  information on the history and accomplishments of the ESP as well as a discussion of how the program is
                  administered.








    SECTION 11
    ALTERNATIVES INCLUDING            I'F
    THE PROPOSED ACTIONS











                                                                                                                              11-3

               11. ALTERNATIVES INCLUDING THE PROPOSED ACTIONS

               A. PROPOSED CENTRAL GULF SALE 142

               1. Alternative A - The Proposed Action

               a. Description

                    Proposed Central Gulf Sale 142 is scheduled to be held in March 1993 and will offer all unleased blocks
               within the CPA. It is estimated that the proposal could result in the discovery and production of 0.14 BBO
               and 1.40 tcf of gas during the time period 1993-2027. There are no areas deferred from the CPA, but there
               are alternatives to the proposed action. The alternatives are to delete biologically sensitive areas near
               topographic features and offer the remaining acreage or to take no action (cancel the sale). For more
               information describing the proposed action and alternatives, see Section I.B.2.
                    The analyses of impacts summarized below and described in detail in Section IV.D.1. are based on a
               development scenario (Base Case) formulated to provide a set of assumptions and estimates on the amounts,
               locations, and timing for OCS exploration, development, and production operations and facilities, both offshore
               and onshore. These are estimates only and not predictions of what will happen as a result of holding the
               proposed sale. A detailed discussion, with tables, of the development scenario and major related impact-
               producing factors is included in Section IV.A_ The following are the estimates of major activities and associated
               impact-producing factors assumed for proposed Sale 142 (Base Case). These estimates and factors were
               utilized in the impact analyses.

                        (1)       During the exploration phase, 1994-2004, there will be 340 wells drilled, resulting in
                                  the following:

                                  -       the generation of 2.42 MMbbI of drilling mud and 0.63 MMbbI of drill
                                          cutting wastes, 18 percent of which will be disposed of onshore;

                                  -       offshore air emissions from well drilling operations of 330 tons of total
                                          suspended particulate matter, 95 tons of total hydrocarbons, 384 tons of
                                          sulphur oxides, 877 tons of carbon monoxide, and 3,288 tons of nitric oxides;

                                  -       6,600 service vessel trips and 23,000 helicopter landings;

                                  -       disturbance from rig emplacements of 144 ha of ocean bottom; and

                                  -       the likelihood of 1 blowout (Section IV.A_2.d.(8)).

                        (2)       During the development phase, 1995-2017, there will be 130 oil wells and 120 gas
                                  wells drilled, resulting in the following:

                                          the generation of 1.69 MMbbI of drilling mud and 0.358 MMbbI of drilling
                                          cutting wastes, a small amount of which will be disposed of onshore;

                                          offshore air emissions from well drilling operations of 162 tons of total
                                          suspended particulate matter, 47 tons of total hydrocarbons, 189 tons of
                                          sulphur oxides, 430 tons of carbon monoxide, and 1,611 tons of nitric oxides;

                                          4,800 service vessel trips and 17,000 helicopter landings;










                   114

                                               the disturbance from fixed structure emplacements of 48 ha of ocean bottom;
                                               and

                                               the likelihood of 1 blowout (Section IV.A.2.d.(8)).

                             (3)      During the production phase, 1995-2026, 0.14 BBO of off and 1.40 tcf of gas will be
                                      produced from 29 platform complexes and one floating production system, resulting
                                      in the following:

                                      -        the open-water discharge of 283 MMbbI of produced water;

                                      -        the onshore disposal of 34 MMbbI of produced waters and 69,000 bbl of
                                               produced sands that were generated offshore;

                                      -        air emissions of 124 tons of total suspended particulate matter, 19,175 tons
                                               of total hydrocarbons, 88 tons of sulphur oxides, 6,590 tons of carbon
                                               monoxide, and 50,592 tons of nitric oxides;

                                      -        6,300 service vessel trips and 328,000 helicopter trips;

                                      -        the removal of 120 ha of commercial fishing area (peak year estimate); and

                                      -        the likelihood of 2 blowouts (Section IV.A.2.d.(8)).

                             (4)      During   platform removal operations, which will occur the year after production
                                      ceases, 20 platforms will be removed using explosives. The remaining platforms, will
                                      be removed by non-explosive methods.

                             (5)      The transportation of gas and oil will require the following:

                                               the construction of 240 kni of gathering pipelines that will connect with
                                               existing trunklines prior to landfall, resulting in the disturbance of77 ha of
                                               bottom and the displacement of 320,000 m3        of sediment;

                                               77 barge trips carrying oil to 8 existing shore terminals along the Texas and
                                               Louisiana coasts; and

                                               2 shuttle tanker trips carrying oil to Mississippi River terminals.

                             (6)      Support activity will result in the following:

                                               No new major onshore support or processing facility construction is expected;
                                               existing OCS-related facilities will be used, with sale-related activities utilizing
                                               about 3 percent, on the average, of the capacities of the onshore
                                               infrastructure.


                                               the use of 18 navigation channels, 7 major channels in Louisiana will be
                                               maintenance dredged periodically and one deepened to support vessel traffic;

                                               56 million liters of bilge water will be discharged in coastal waters from
                                               service vessels traveling to 28 existing bases;

                                               206,000 helicopter coastal crossings to reach 27 helicopter hubs; and












                                                                                                                                11-5


                                          air emissions from service vessels and helicopters of 680 tons of total
                                          suspended particulate matter, 495 tons of total hydrocarbons, 177 tons of
                                          sulphur oxides, 1,466 tons of carbon monoxide, and 9,264 tons of nitric
                                          oxides.

                         (7)      Twenty-one crude oil spills greater than 1 and less than or equal to 50 bbl, one spill
                                  between 50 and 1,000 bbl, and one spill of 1,000 bbl or greater are assumed to occur.
                                  The large spill is projected to be 6,500 bbl and has a 16 percent chance of land
                                  contact

                         (8)      Fewer than 10 crude oil spills greater than one and less than 50 bbl are assumed to
                                  occur from onshore support activities.

                         (9)      Total employment from all activities associated with the exploration, development,
                                  and production of oil and gas generated as a result of Sale 142 is 58,500 personnel,
                                  45 percent of which will be directly employed.

                b. Summary of Impacts

                     The following summarizes the detailed impact analyses of Section IV.D.l.a. It should be emphasized that
                these are impact summaries and that the reader should refer to Section IV.D.La. for detailed information
                regarding particular resources. Note that these summaries are limited to the impact of the proposed action
                (Base Case). The impacts under the Cumulative Analysis are assessed in Section IV.D.l.d. and are not
                summarized here. Table S-3 compares the impacts of Alternatives A-C and the cumulative impacts on each
                resource category estimated as a result of the various scenarios.
                     The following impact analyses are for the proposed action and include the following potential stipulations
                as part of the proposed action: the Topographic Features Stipulation, the Live Bottom Stipulation, the
                Archaeological Resources Stipulation, and the Military Stipulation. The analyses to follow presume full
                compliance with the proposed stipulations.
                     To facilitate the analyses, the Federal offshore area is divided into subareas. The CPA is comprised of
                four subareas (C-1, C-2, C-3, and C-4) and the coastal region is divided into four coastal subareas (C-1, C-2,
                C-3, and C-4). These subareas are delineated on Figure IV-1.

                Sensitive Coastal Environments


                     Coastal Barrier Beaches (Section 1VD.1.a.(1)(a))

                     Oil-spill contact to a barrier island could result in erosional changes in the barrier if cleanup operations
                removed large quantities of sand. Because of the very low probability of occurrence and contact from either
                an offshore or onshore spill of greater than 50 bbl, however, it is assumed that no contact from such a spill will
                occur. Several spills less than 50 bbl are assumed to contact coastal areas of the CPA under the Base Case
                scenario from barge and pipeline accidents and from offshore sources. These spills will contact mainly the
                landward side of barrier islands, will affect only a short stretch of beach, and will be cleaned within a week with
                no effects on beach morphology.
                     Impacts from onshore and nearshore construction of OCS-related infrastructure (pipeline landfalls,
                navigation channels, service bases, platform yards, etc.) are not expected to occur because no new infrastructure
                construction is anticipated as a result of the proposed action. Although some maintenance dredging is expected
                to occur, this activity has not been shown to have a negative impact on barriers, and the need for dredging
                cannot be attributed to the small percentage of vessel traffic in these channels accounted for by Base Case
                activities.
                     It follows from the above that activities resulting from the proposed action will not have a significant
                impact on coastal barriers.











                 11-6


                     Conclusion


                     The Proposed Action is not expected to result in permanent alterations of barrier beach configurations,
                 except in localized areas downdrift from navigation channels that have been dredged and deepened. The
                 contribution to this localized erosion is expected to be less than 1 percent.

                     Wetlands (Section IVD.I.a(1)(b))

                     No oil spills of 1,000 bbl or greater offshore or inshore sources are expected to occur and contact coastal
                 wetlands under the Base Case scenario. Although several spills greater than I and less than or equal to 50 bbl
                 are expected to contact wetlands from inshore barge and pipeline accidents in coastal Louisiana, only small
                 areas (several hectares) of wetlands will be contacted by high-enough concentrations of oil to result in the
                 conversion of wetlands to open water habitat. Seagrass beds will be contacted by such low concentrations of
                 oil from these spills that no impacts are expected.
                     No new dredging projects for pipelines or navigation channels are projected. Few to no impacts from
                 maintenance dredging are expected given the small contribution of OCS vessel traffic to navigational usage of
                 the channels. Furthermore, alternative dredge material disposal methods that could be used to enhance coastal
                 wetland growth exist.
                     Erosion of wetlands from OCS vessel wakes is not expected to result in more than 5.5 ha of wetlands loss
                 during the 35-year life of the proposed action.

                     Conclusion


                     The proposed action is expected to result in dieback and mortality of 10 to 15 ha of wetlands vegetation
                 as a result of contacts from onshore oil spills. All but 2 ha of these wetlands will recover within 10 years; the
                 remaining 2 ha will be converted to open water. About 5.5 ha of wetlands are projected to be eroded along
                 channel margins as a result of OCS vessel wake erosion, and 3.5 ha of wetlands are projected to be created
                 as a result of beneficial disposal of dredged material from channel-deepening projects.

                 Sensitive Offshore Resources

                     Live Bottoms (Pinnacle Trend) (Section IVDl.a.(2)(a))

                     Activities resulting from the proposed action are not expected to have a high level of impact on the
                 pinnacle trend environment, since these activities would be restrained by the implementation of the Live
                 Bottom Stipulation. The impact to the pinnacle trend area as a whole is expected to be slight because no
                 community-wide impacts are expected. The inclusion of the potential Live Bottom Stipulation would preclude
                 the occurrence of the most potentially damaging of these activities. The action is judged to be infrequent
                 because of the limited operations in the vicinity of the pinnacles and the small size of many of the features.
                 Potential impact levels from large oil spills, blowouts, pipeline emplacement, muds and cuttings discharges, and
                 structure removals would be very low because of the effectiveness of the proposed Live Bottom Stipulation.
                 The frequency of impacts to the pinnacles is rare, and the severity is judged to be slight because of the
                 widespread nature of the features.

                     Conclusion


                     The impact of the Base Case of the proposed action on the pinnacle trend region in the Gulf of Mexico
                 is expected to be such that any changes in the regional physical integrity, species diversity, or biological
                 productivity of the hard-bottom region would recover to pre-impact conditions in less than 2 years, more
                 probably on the order of 2-4 months.











                                                                                                                                11-7

                    Deep-waterBenthic Communities (Section IVD.I.a.(2)(b))

                    The only impact-producing factor threatening the chemosynthetic communities is physical disturbance of
                the bottom, which would destroy the organisms comprising these communities. Such disturbance would come
                from those OCS-related activities associated with pipelaying, anchoring, structure emplacement, and seafloor
                blowouts. Only structure emplacement is considered to be a threat, and then only to the high-density (Bush
                Hill-type) communities; the widely distributed low-density communities would not be at risk. The provisions
                of NTL 88-11 (currently in effect), requiring surveys and avoidance prior to drilling, will greatly reduce, but not
                completely eliminate, the risk.

                    Conclusion


                    The proposed action is expected to cause little damage to the physical integrity, species diversity, or
                biological productivity of either the widespread, low-density chemosynthetic communities or the rarer, widely
                scattered, high-density Bush Hill-type chemosynthetic communities. Recovery from any damage is expected
                to take less than two years.

                    Topographic Features (Section IVD.1.a(2)(c))

                    Several impact-producing factors (anchoring, structure emplacement, effluent discharges, blowouts, oil
                spills, and structure removals) may threaten the communities of the topographic features. Because of the
                effectiveness of the proposed Topographic Features Stipulation, operational discharges (drilling muds and
                cuttings, produced waters) would have little impact on the biota of the banks. Recovery from any impact would
                be rapid.
                    Blowouts may similarly cause damage to benthic biota, but due to the application of the proposed
                Topographic Features Stipulation, they would have little impact on the biota of the banks. Recovery from any
                impact would be rapid.
                    Oil spills (there is an estimated 6% chance of an oil spill greater than or equal to 1,000 bbl occurring in
                the Central Gulf as a result of this proposed action) will cause damage to benthic organisms if the oil contacts
                the organisms; such contact is likely only from spills from blowouts, which, because of the proposed
                Topographic Features Stipulation, would not occur very near to the biota of the banks.

                    Conclusion


                    The proposed action is expected to cause little to no damage to the physical integrity, species diversity, or
                biological productivity of the habitats of the topographic features of the Gulf of Mexico. Small areas of 5-10
                In2 would be impacted, and recovery from this damage to pre-impact condition is expected to take less than
                2 years, probably on the order of 2-4 weeks.

                Water Quality (Section IVD.1.a.(3))

                    Coastal and Estuarine Waters

                    All existing onshore infrastructure and associated coastal activities occurring in support of proposed Sale
                142 will contribute to the degradation of regional coastal and nearshore water quality to a minor extent because
                each provides a low measure of continuous contamination and because discharge locations are widespread.
                Process, cooling, boiler, and sewage water effluents will be discharged due to the use of the existing
                infrastructure and facilities. Because of the new Louisiana regulations banning the discharge of produced
                waters into State waters, the onshore separation, treatment, and disposal of up to 34 MMbbl of OCS produced
                water is not expected to impact coastal and nearshore water quality. Based on the new regulations, it is
                expected that these waters will be reinjected onshore, separated/treated onshore, and then transported offshore
                for disposal or discharged into the Mississippi River. Based on the new regulations, it is expected that these
                waters will be reinjected onshore, separated/treated onshore and then transported offshore for disposal, or











                   11-8


                   discharged into the Mississippi River. The OCS-related vessel traffic is likely to impact water quality through
                   routine releases of bilge and ballast waters, chronic fuel and tank spills, trash, and low-level releases of the
                   contammiants in antifouling paints. The improper storage and disposal of oilfield wastes and contaminated
                   oilfield equipment would adversely impact surface and ground waters in proximity to disposal facilities, cleaning
                   sites, and scrap yards.

                       Marine Waters


                       Based on projected sale-related support activities, offshore Subarea C-1 would receive the greatest portion
                   of pipeline burial activities, whereas, offshore Subareas C-3 and C-4 would receive the Largest amounts of
                   operational discharges. Immediate effects would be brought about by increased drilling, construction and
                   pipelaying activities, causing increased water column turbidity (lasting for several hours widi mud discharges
                   and several weeks with dredging-pipelaying activities). Proposed produced water and drilling fluid discharges
                   will encounter rapid dispersion in marine waters and be rapidly diluted within the immediate vicinity of the
                   discharge source. Drilling fluid (mud) plumes will be diluted to background levels within a period of hours
                   and/or within several hundred meters of the discharge source. Significant increases in water concentrations of
                   dissolved and particulate hydrocarbons and trace metals are not expected outside the initial mixing zone or
                   immediate vicinity of the discharge source. Higher concentrations of trace metals, salinity, terriperature, organic
                   compounds, and radionuclides, and lower dissolved oxygen may be present near the discharge source.
                       Program-related spills will introduce oil into coastal and offshore waters and create elevated hydrocarbon
                   levels (up to 100+ lLgll) within affected waters. Much of the oil will be dispersed throughout the water column
                   over several days to weeks. Little effect to water use is anticipated from these spills and then only in an area
                   near the source and slick.


                   Conclusion


                       An identifiable change to the ambient concentration of one or more water quality parameters will be
                   evident up to several hundred to 1,000 m from the source for periods lasting up to several weeks in duration
                   in marine and coastal waters. Chronic, low-level pollution related to the proposal will occur throughout the
                   life of the proposed action.

                   Air Quality (Section IVD.I.a.(4))

                       Emissions of pollutants into the atmosphere from the activities associated with the proposed action are
                   likely to have a low impact on offshore air quality because of the prevailing atmospheric conditions, emission
                   heights, and pollutant concentrations. Onshore impact on air quality from emissions from the OCS activities
                   are estimated to be low because of the atmospheric regime, the emission rates, and distance of these emissions
                   from the coastline. Section IV.D.l.a.(4) is based on average conditions; however, there will be days of low
                   mixing heights and wind speeds which could increase impact levels. These conditions are characterized by fog
                   formation, which in the Gulf occurs about 35 days a year mostly during winter. Impact from these conditions
                   is reduced in winter because the onshore winds have the smallest frequency and rain removal is greatest

                   Conclusion


                       Emissions of pollutants into the atmosphere are expected to have concentrations that would not change
                   onshore air uality classifications. Increase in onshore concentrations of air pollutants are. estimated to be
                   about 1 Agm% (box model steady concentrations). This concentration will have minimal impacts during winter
                   because onshore winds occur only about 37 percent of the time and maximum impacts in summer when
                   onshore winds occur 61 percent of the time.












                                                                                                                                           11-9


                Coastal and Marine Mammals


                     Marine Mammals (Section IVD.Laff)(a))

                          Nonendangered and Nonthreatened Species

                     Activities resulting from the proposed action have a potential to cause detrimental effects on
                nonendangered cetaceans. These marine mammals could be impacted by operational discharges, helicopter
                and vessel traffic, platform noise, explosive platform removals, seismic surveys, oil spills, and off-spill response
                activities. The effects of the majority of these activities are estimated to be sublethal. Potential lethal effects
                are estimated only from off spills greater than or equal to 1,000 bbl (one 6,500-bbl spill is assumed). Sale-
                related oil spills of any size are expected to seldom contact nonendangered and nonthreatened marine
                mammals.


                          Conclusion


                     The impact of the Base Case scenario on nonendangered and nonthreatened marine mammals within the
                potentially affected area is expected to result in sublethal effects that are chronic and could result in persistent
                physiological or behavioral changes, as well as some degree of avoidance of the impacted area(s).

                          Endangered and 77treatened Species

                     Activities resulting from the proposed action have a potential to cause detrimental effects on endangered
                marine mammals. These cetaceans could be impacted by operational discharges, helicopter and vessel
                traffic, platform noise, explosive platform removals, seismic surveys, oil spills, and oil-spill response activities.
                The effects of the majority of these activities are estimated to be sublethal. Potential lethal effects are
                estimated only from oil spills greater or equal to 1,000 bbl (one 6,500-bbl spill is assumed). Sale-related oil
                spills of any size are expected to seldom contact endangered and threatened marine mammals.

                          Conclusion


                     The impact of the Base Case scenario on endangered and threatened marine mammals within the
                potentially affected area is expected to result in sublethal effects that are chronic and could result in persistent
                physiological or behavioral changes, as well as some degree of avoidance of the impacted area(s).

                     Alabama, Choctawhatchee, and Perdido Key Beach Mice (Section IV.D.I.a.(5)(b))

                     Activities resulting from the proposed action have a potential to cause detrimental effects on Alabama and
                Perdido Key beach mice. Beach mice could be impacted by oil spills and oil-spill response activities. It is
                expected that there will seldom be interaction between these events and beach mice or their habitats, as well
                as some degree of avoidance of the impacted area(s).

                     Conclusion


                     The impact of the Base Case scenario on Alabama, Choctawhatchee, and Perdido Key beach mice within
                the potentially affected area is expected to result in sublethal effects that seldom occur and may cause short-
                term physiological or behavioral changes.

                Marine nriles (Section IVD.La.(6))

                     Activities resulting from the proposed action have a potential to cause detrimental effects on marine turtles.
                Marine turtles could be impacted by structure installation, pipeline placement, dredging, operational discharges,
                OCS-related trash and debris, vessel traffic, explosive platform removals, oil-spill response activities, and oil











                   11-10


                   spills. The effects of the majority of these activities are estimated to be sublethal. Potential lethal effects are
                   estimated only from oil spills greater than or equal to 1,000 bbl (one 6,500-bbl spill is assumed). Sale-related
                   oil spills of any size are expected to seldom contact marine turtles.

                   Conclusion


                       The impact of the Base Case scenario on marine turtles within the potentially affected area is estimated
                   to result in sublethal effects which are chronic and could result in persistent physiological or behavioral changes.

                   Coastal and Marine Birds


                       Nonendangered and Nonthreatened Species (Section IVD. 1. a. (7) (a))

                       Activities resulting from the proposed action have the potential to cause detrimental effects on Central
                   Gulf coastal and marine birds. Coastal and marine birds may be impacted by helicopter and service-vessel
                   traffic, onshore pipeline landfalls, entanglement in and ingestion of offshore oil- and gas-related plastic debris,
                   and oil spills. It is estimated that the effects from the major impact-producing factors on coastal and marine
                   birds are negligible and of nominal occurrence. As a result there will be no perceivable disturbance to Gulf
                   coastal and marine birds.


                       Conclusion


                       The impact of the Base Case scenario on nonendangered and nonthreatened coastal and marine birds
                   within the potentially affected area is expected to result in no discernible decline in a population or species and
                   no change in distribution and/or abundance on a local or regional scale. Individuals experiencing sublethal
                   effects will recover to pre-disturbance condition in less than one generation.

                       Endangered and 7hreatened Species (Section 1VDl.a(7)(b))

                       The brown pelican, Arctic peregrine falcon, bald eagle, and piping plover may be impacted by helicopter
                   and service vessel traffic, onshore pipeline landfalls, entanglement in and ingestion of offshore oil- and gas-
                   related plastic debris, and off spills. The effects of these activities are estimated to be sublethal. Potential
                   lethal effects are estimated only from oil spills greater than or equal to 1,000 bbl (one 6,500-bbl spill is
                   assumed). Sale-related oil spills of any size are estimated to be extraordinary events that will rarely contact
                   endangered and threatened birds or their critical feeding, resting, or breeding habitats.

                       Conclusion


                       The impact of the Base Case scenario on endangered and threatened birds within the potentially affected
                   area is expected to result in no discernible decline in a population or species and no change in distribution
                   and/or abundance on a local or regional scale. Individuals experiencing sublethal effects will recover to pre-
                   disturbance condition in less than one generation.

                   Gulf Sturgeon (Section IVD.I.a.(8))

                       The Gulf sturgeon can be impacted by oil spills resulting from the proposed action. The impact of this
                   scenario on Gulf sturgeon is estimated to be inconsequential.

                   Conclusion


                       The impact of the Base Case scenario on the Gulf sturgeon within the potentially affected area is expected
                   to result in sublethal effects and cause short-term physiological or behavioral changes.












               Commercial Fisheries (Section IVD.I.a. (9))

                    Activities resulting from the proposed action have the potential to cause detrimental effects to Central Gulf
               commercial fisheries. It is estimated that the effects from the major impact-producing factors on commercial
               fisheries in the CPA are inconsequential and of nominal occurrence. Asa result, there will belittle discernible
               disturbance to Gulf commercial fisheries.


               Conclusion


                    The impact of the Base Case scenario on commercial fisheries within the potentially affected area is
               expected to result in a short-term decrease in a portion of a population of commercial importance, in an
               essential habitat, or in commercial fisheries on a local scale. Any affected population is expected to recover
               to pre-disturbance condition in one generation.

               Recreational Resources and Activities


                    Beach Use (Section 1VD.1.a.(10)(a))

                    A few oil spills of greater than 1 and less than or equal to 50 bbl are likely to affect portions of CPA
               beaches, with little disruption of recreational activities. Marine debris will be lost from time to time from OCS
               operations associated with drilling 590 new wells and producing oil and gas from 30 new platform complexes
               throughout the CPA over the next 35 years. Intermittent oiling and wash up of debris will detract from
               enjoyment of recreational beaches. A drilling rig and production platform in the nearshore area off Louisiana
               and Mississippi could impact the natural seascape viewed from some wilderness beaches in coastal Subarea C-3.
               Helicopter and vessel traffic will add periodic offsite noise pollution affecting wilderness beach users.

                    Conclusion


                    The proposed action is expected to result in minor pollution events and nearshore operations that may
               adversely affect the enjoyment of some beach users on Louisiana and Texas beaches.

                    Marine Fishing (Section 1VD.1.a.(10)(b))

                    The proposed action is expected to result in up to 16 new platform complexes that will attract fishermen
               and improve fishing success in the nearshore waters (within 30 miles) of the CPA over the next 5-35 years.

                    Conclusion


                    Platforms installed within 30 mi of shore attract fishermen and improve fishing for a period of about 20
               years, but they are unlikely to affect offshore fishing patterns in general unless the platforms are installed in
               nearshore locations where no platforms currently exist.

               Archaeological Resources

                    Historic (Section IVD.1.a.(11)(a))

                    The greatest potential impact to an historic archaeological resource as a result of the proposed action
               would result from a contact between an OCS offshore activity (platform installation, drilling rig emplacement,
               dredging, or pipeline project) and an historic shipwreck. The areas of the northern Gulf of Mexico, which are
               considered to have a high probability for historic period shipwrecks, have recently been redefined as a result
               of an MMS-funded study (Garrison et al., 1989). The redefinition of the high-probability areas has reduced
               the total number of lease blocks with a high probability for shipwrecks from 3,410 to 2,263. A new NTL for
               archaeological surveys in the Gulf of Mexico Region (NTL 91-02) has increased the survey linespacing density
               for historic shipwreck surveys from 150 in to 50 in.











                  11-12


                       Most other activities associated with the proposed action are expected to have very low hupacts on historic
                  archaeological resources. No new onshore infrastructure construction or pipeline landfalls are expected as a
                  result of the proposed action. Historic cultural resources, therefore, will not be affected toy these activities.
                  The chance of contact from an off spill associated with the proposed action is very low. Furthermore, the
                  major impact from an off-spill contact on an historic coastal site, such as a fort or lighthouse, would be visual
                  due to oil contamination. These impacts would be temporary and reversible. Impacts from dredging are
                  expected to be low.
                       The OCS activity could contact a shipwreck because of incomplete knowledge on the location of shipwrecks
                  in the Gulf. Although this occurrence is not probable, such an event would result in the disturbance or
                  destruction of important historic archaeological information. Other factors associated with the proposed action
                  are not expected to affect historic archaeological resources.

                       Conclusion


                       There is a very small possibility of an impact between OCS oil and gas activities and a historic shipwreck
                  or site. Should such an impact occur, unique or significant historic archaeological information could be lost.

                       Prehistoric (Section RID.I.a.(11)(b))

                       Several impact-producing factors may threaten the prehistoric archaeological resources of the Central Gulf.
                  An impact could result from a contact between an OCS activity (pipeline and platform in-stallations, drilling
                  rig  emplacement and operation, dredging, and anchoring activities) and a prehistoric site located on the
                  continental shelf. The archaeological surveys and archaeological clearance of sites that are required prior to
                  an operator beginning oil and gas activities in a lease block are estimated to be 90 percent effective at
                  identi@yiiig possible prehistoric sites. The survey and clearance provide a significant reduction in the potential
                  for a damaging interaction between an impact-producing factor and a prehistoric site. There is a very small
                  possibility of an OCS activity contacting a prehistoric site. Should such contact occur, there could be damage
                  to or loss of significant or unique archaeological information.
                       Onshore development as a result of the proposed action could result in the direct physical disturbance from
                  new facility construction, pipeline trenching, and new navigation canal dredging. None of these activities is
                  expected to occur under the Base Case. The impact level from these factors is considered to be very low.
                       Should an oil spill contact a coastal prehistoric site, the potential for dating the site using radiocarbon
                  methods could be destroyed. Oil-spiff cleanup operations could physically impact coastal prehistoric sites.
                  Previously unrecorded sites could also experience an impact from oil-spill cleanup operations on beaches. The
                  probability of a spill of 1,000 bbl or greater (one 6,500-bbl spill is assumed) occurring and contacting a coastal
                  prehistoric site within 10 days is very low (1%), and it is assumed that no contact will occur. A few spills
                  greater than 1 and less than or equal to 50 bbl are assumed to contact the coast, but these small spills would
                  probably not cover an exposed site, such as a shell midden, with enough oil to contaminate all the datable
                  organic remains. The impact level from oil-spill contact is expected to be very low.

                       Conclusion


                       There is a very small possibility of an impact between OCS oil and gas activities and a prehistoric site.
                  Should such an impact occur, there could be damage or loss of significant or unique prehistoric archaeological
                  information.


                  Socioeconomic Conditions


                       Population, Labor, and Empleyment (Section 1VD.1.a.(l2)(a))

                       Peak annual changes in the population, labor, and employment of all coastal subareas in the Central and
                  Western Gulf resulting from the proposed action in the Central Gulf represent less than 1 percent of the levels
                  expected in the absence of the proposed action in the Central Gulf. Only 2 percent of the total employment
                  resulting from the proposed action is expected to affect the coastal subareas of the Western Gulf. Employment











                                                                                                                                  11-13


                resulting from oil-spill clean-up activities due to the proposed action is negligible. It is expected that
                employment demands in support of the proposed action will be met with the existing population and available
                labor force.


                    Conclusion


                    The Base Case impact of the proposed action in the Central Gulf on the population, labor, and
                employment of the counties and parishes of the Central and Western Gulf coastal impact area is expected to
                be less than I percent of the levels expected in the absence of the proposal.

                    Public Services and Inftastructure (Section IVD.I.a.(12)(b))

                    Impacts to public services and infrastructure would be related to dramatic increases or decreases in
                population. Specific impact-producing factors examined in this analysis include fluctuations in work force,
                migration into or out of the coastal subareas, and the relatively high wages made by personnel involved in the
                oil and gas industry. An analysis of historical trends indicates that population impacts of greater than 1 percent
                involve positive net migration into a given area. Under the Base Case, population impacts are not expected
                to exceed the peak year impact of 0.24 percent. No positive net migration into the coastal subareas of the
                Central and Western Gulf of Mexico is expected to occur as a result of the proposed action. It is expected that
                employment will occur from those currently employed in the oil and gas industry, as well as unemployed,
                underemployed, and new employees already living in the area. In addition, jobs created by the proposal would
                likely reduce the amount of migration out of the coastal subareas when compared to scenarios without the
                proposal. It is expected that employees leaving public service and infrastructure related jobs could be replaced
                from the existing labor pool.

                    Conclusion


                    Population and employment impacts that result from the proposed action under the Base Case scenario
                will not result in disruptions to community infrastructure and public services beyond what is anticipated by in-
                place planning and development agencies.

                    Social Patterns (Section ITID.I.a.(12)(c))

                    Impacts to social patterns would be related to dramatic changes in population and the disruption of
                environmental resources, as well as conditions inherent to OCS-related employment (i.e., work scheduling and
                rate of pay). Specific impact-producing factors examined in this analysis include fluctuations in the workforce,
                migration into or out of the coastal subareas, work scheduling, displacement from traditional occupations, and
                relative income. An analysis of historical trends indicates that population impacts of greater than 1 percent
                typically involve positive net migration into a given area. Under the Base Case, population impacts are not
                expected to exceed the peak year impact of 0.25 percent. No positive net migration into coastal subareas of
                the Central and Western Gulf of Mexico is expected to occur as a result of the proposal. It is expected that
                employment will occur from those currently employed in the oil and gas industry, as well as unemployed,
                underemployed, and new employees already living in the area. It is expected that jobs created by the proposal
                would likely reduce the amount of out-migration when compared to scenarios without the proposal. It is
                expected that minor displacement from traditional occupations will occur as a result of the proposed action.
                This displacement will be mitigated, to some extent, by the extended work schedule associated with OCS-
                related employment. The extended work schedule is expected to have some deleterious effects on family life
                in pertinent, individual cases. Impacts caused by the displacement of traditional occupations and relative wages
                are expected to occur to a minimal extent.











                  11-14


                       Conclusion

                       It is expected that no net migration will occur as a result of the proposed action. Deleterious impacts to
                  social patterns are expected to occur in some individual cases as a result of extended work schedules,
                  displacement from traditional occupations, and relative wages.

                  c. Mitigating Measures

                       Measures have been developed to mitigate possible impacts of OCS activities on environmental resources
                  and non-OCS activities. The four stipulations presented below have been applied to appropriate OCS leases
                  for many years. These stipulations, while proven effective, are considered as potential mitigating measures in
                  this EIS. The Secretary will make a decision prior to Sale 142 on whether or not to apply these measures to
                  appropriate leases resulting from the sale. The analyses in this EIS of the impacts to the resources to which
                  these stipulations apply assume that the measures will be in place. However, the analyses also contain a
                  description of possible impacts without the protection afforded by the stipulations.

                  (1) Topographic Features Stipulation

                       The Topographic Features Stipulation was formulated based on consultation with various Federal agencies
                  and comments solicited from State, industry, environmental organizations, and academic representatives. The
                  stipulation wording is based on years of scientific information collected since the inception of the stipulation.
                  This information includes various Bureau of Land Management/MMS-funded studies on the topographic highs
                  in the Central Gulf, numerous stipulation-imposed, industry-funded monitoring reports, and the National
                  Research Council (NRC) report entitled Drilling Discharges in the Marine Environment (1983).
                       The requirements in the stipulation are based on the following facts:

                           (a)    Shunting of the drilling effluent to the nepheloid layer confines the effluent to a level
                                  deeper than that of the living reef of a high-relief topographic feature. Shunting is
                                  therefore an effective measure for protecting the biota of high relief topographic
                                  features (Bright and Rezak, 1978; Rezak and Bright, 1981; NRC, 1983).

                           (b)    The biological effect on the benthos from the deposition of nonshunted discharge are
                                  mostly limited to within 1,000 in of the discharge (NRC, 1983).

                           (c)    The biota. of topographic features can be categorized into depth-related zones defined
                                  by degree of reef-building activity (Rezak and Bright, 1981; Rezak et al., 1983 and
                                  1985).

                       The stipulation establishes No Activity Zones at the topographic features. The zone is defined by the 85-m
                  isobath because, generally, the biota shallower than 85 in are more typical of the Caribbean reef biota, while
                  the biota deeper than 85 in are similar to soft-bottom organisms found throughout the Gulf. Where a bank
                  is in water depths less than 85 in, the deepest closing isobath defines the No Activity Zone for that bank.
                  Within the No Activity Zone, no operations, anchoring, or structures are allowed. Outside the No Activity
                  Zones, additional restrictive zones are established within which oil and gas operations could, occur, but within
                  which drilling discharges would be shunted.
                       The stipulation requires that all effluents within 1,WO in of those banks with the antipatharian-transitional
                  zone be shunted to within 10 in of the seafloor. Banks containing the more sensitive and productive algal-
                  sponge zone require a shunt zone extending 1 nmi and an additional 3-nmi shunt zone for development. (The
                  reported algal-sponge zone at Sackett Bank is mostly dead; Sackett Bank is, therefore, not accompanied by this
                  restriction.) Because Sweet Bank in the Central Gulf is small and surrounded by very deep water (the depth
                  drops very quickly to greater than 200 in around the bank), it does not require the protection of the shunt
                  zones; therefore, only a "No Activity Zone" is established there.
                       The banks and corresponding blocks to which this stipulation may be applied in the CAntral Gulf are as
                  follows:











                                                                                                                                  11-15


                            Bank Name               Isobath (meters)               Bank Name               Isobath (meteW

                          McGrail Bank                   85                      Parker Bank                     85
                          Bourna Bank                    85                      Fishnet Bank   2                76
                          Rezak Bank                     85                      Jakkula Bank                    85
                          Sidner Bank                    85                      Sweet Bank'                     85
                          Sonnier Bank                   55                      Rankin Bank                     85
                          Sackett Bank2                  85                      29 Fathom Bank                  64
                          Ewing Bank                     85                      Bright Bank                     85
                          Diaphus Bank    2              85                      Geyer Bank3                     85
                          Alderdice Bank                 80                      MacNeil Bank3                   82

                          'Only paragraph (a) of the stipulation applies.
                          20nly paragraphs (a) and (b) apply.
                          3 Western Gulf of Mexico bank with a portion of its "3 Mile Zone" in the Central Gulf of Mexico.

                    The stipulation reads as follows:

                                                         Topographic Features Stipulation
                                                              (Central Planning Area)

                         (a)   No activity including structures, drilling rigs, pipelines, or anchoring will be allowed
                               within the fisted isobath ("No Activity Zone") of the banks as listed above.

                         (b)   Operations within the area shown as "1,000 Meter Zone" shall be restricted by shunting
                               all drill cuttings and drilling fluids to the bottom through a downpipe that terminates
                               an appropriate distance, but no more than ten meters, from the bottom.

                         (c)   Operations within the area shown as "l Mile Zone" shall be restricted by shunting an
                               drill cuttings and drilling fluids to the bottom through a downpipe that terminates an
                               appropriate distance, but no more than ten meters, from the bottom. (Where there is
                               a "I Mile Zone" designated, the "1,000 Meter Zone" in paragraph (b) is not designated.)

                         (d)   Operations within the area shown as "3 Mile Zone" shall be restricted by shunting all
                               drill cuttings and drilling fluids from development operations to the bottom through a
                               downpipe that terminates an appropriate distance, but no more than ten meters, from
                               the bottom.


               Effectiveness of the Lease Stipulation

                    The coral and associated communities at the crest and on the upper flanks of the topographic features
               would be severely and adversely impacted (i.e., have an expected impact level of very high) by oil and gas
               activities resulting from the proposed action if such activities took place on or near these communities without
               the Topographic Features Stipulation. The USDOI has recognized this problem for some years, and since 1974
               stipulations have been made a part of leases on blocks on or near these biotic communities so that impacts
               from nearby oil and gas activities were mitigated to the greatest extent possible. This stipulation does not
               prevent the recovery of oil and gas resources, but it does serve to protect valuable and sensitive biological
               resources.
                    The analyses of the proposed actions in the Final EIS for Sales 131, 135, and 137 (USDOI, MMS, 1990a)
               were done without the stipulations in place. A thorough analysis of the impacts of oil and gas activities as they
               relate to topographic features is presented there. The following is a summary of that analysis, which is hereby
               incorporated by reference.
                    The purpose of the stipulation is to protect the biota of the topographic features from adverse effects due
               to routine oil and gas activities. Several impact-producing factors may threaten the communities of the











                   11-16


                   topographic features. Anchoring of vessels and structure emplacement result in physical disturbance of the
                   benthic environment and are the most likely activities to cause permanent or long-lasting impacts to sensitive
                   offshore habitats. Recovery from damage caused by such activities may take 10 or more years. Operational
                   discharges (drilling muds and cuttings, produced waters) may impact the biota of the banks due to turbidity
                   and sedimentation, resulting in death to benthic organisms in large areas. Recovery from such damage may
                   take 10 or more years. Blowouts may similarly cause damage to benthic biota by resuspending sediments,
                   causing turbidity and sedimentation, resulting in death to benthic organisms. Recovery from such damage may
                   take up to 10 years. Fortunately, blowouts seldom occur in the Gulf. Oil spills will cause damage to benthic
                   organisms if the off contacts the organisms; such contact is likely only from spills from blowouts. Structure
                   removal using explosives (as is generally the case) results in water turbidity, sediment deposition, and potential
                   explosive shock-wave impacts. Such effects include physical damage from anchoring and rig emplacement and
                   potential toxic and smothering effects from muds and cuttings discharges. Severe damage to benthic organisms
                   could result Recovery from such damage could take more than 10 years. The above activities resulting from
                   this proposal, especially bottom-disturbing activities, have a potential for causing very high impacts to the biota
                   of the topographic features. While some of the activities are expected to result in lower impacts, those having
                   the greatest impacts are also those most likely to occur. The proposed action, without benefit of the
                   Topographic Features Stipulation or comparable mitigation, is expected to have a very high impact on the
                   sensitive offshore habitats of the topographic features.
                       The Topographic Features Stipulation has been used on leases since 1974, and this experience shows
                   conclusively that the stipulation effectively prevents damage to the biota of these banks from routine oil and
                   gas activities. Anchoring on the sensitive portions of the features by the oil and gas industry has been
                   prevented. Monitoring studies conducted, as required by the stipulation have demonstrated that the shunting
                   requirements are effective in preventing the muds and cuttings from impacting the biota of the banks. The
                   stipulation, if adopted for this proposed action, would continue to protect the biota of the banks, specifically
                   as discussed below. Mechanical damage resulting from off and gas operations is probably the single most
                   severe impact to benthic areas. The "No Activity Zone" designation would completely eliminate this threat
                   from leasing activities. The sensitive biota within the zones will thus be protected.
                       The stipulation requires that all effluents within 1,000 in of Sackett, Fishnet, and Diaphus Banks,
                   categorized by Rezak and Bright (1981) as Category C banks, be shunted into the nepheloid layer.
                       The categories of Rezak and Bright (1981) and their definitions are as follows:

                           Category A.-    zone of major reef-building activity; maximum environmental protection
                                           recommended;

                           Category B:     zone of minor reef-building activity; environmental protection recommended;

                           Category C:     zone of negligible reef-building activity, but crustose algae present;
                                           environmental protection recommended; and

                           Category D:     zone of no reef-building or crustose algae; additional protection not necessary.

                       The biota of the antipatharian zone located at these banks will thus be protected from impact from drilling
                   discharges within the 1,000-in zone because the potentially harmful materials (in drilling muds) win be trapped
                   in the bottom boundary layer and will not move up the bank where the biota of concern are located. Surface
                   drilling discharge at distances greater than 1,000 in from the bank is not expected to impact the biota since
                   effects from drilling discharge are limited to 1,000 in.
                       The stipulation protects the remaining Category A and B banks with greater restrictions. Surface discharge
                   will not be allowed within I nmi of these more sensitive banks. Thus, the stipulation prevents impacts to the
                   biota of these sensitive banks from drilling discharges within 1 nmi. Surface discharges outside of 1 nmi are
                   not expected to impact the biota of the banks, as effects from surface discharge are limited to 1,000 in.
                   However, it is possible that because multiple wells from a single platform (surface location) are typically drilled
                   during development operations, extremely small amounts of muds discharged more than 1 rimi from the bank
                   may reach the bank. In order to eliminate the possible cumulative effect of muds discharged during












                                                                                                                                 11-17


                development drilling outside of 1 nmi, the stipulation imposes a "3 Mile Zone" in which shunting of
                development well effluent will be required.
                    The stipulation will prevent damage to the biota of the banks from routine oil and gas activities resulting
                from the proposed action. Furthermore, oil and gas resources present near such areas could be recovered.
                However, the stipulation will not protect the banks from the adverse effects of an accident such as a large
                blowout on a nearby oil or gas operation.

                (2) Live Bottom (Pinnack Trend) Stipulation

                    A small portion of the northeastern CPA is characterized by a pinnacle trend, which is classified as a live
                bottom under the definition in the stipulation. The pinnacles in the region could be impacted from physical
                damage of unrestricted oil and gas activities, as noted in Section IV.D.La.(2)(a). The Live Bottom Stipulation
                is intended to protect the pinnacle trend and the associated hard-bottom communities from damage and, at
                the same time, provide for recovery of potential oil and gas resources.

                    The stipulation reads as follows:

                                                    Live Bottom (Pinnacle Trend) Stipulation
                                                             (Central Planning Area)

                         (To be included only on leases in the following blocks: Main Pass Area, South and East
                         Addition Blocks 190, 194, 198, 219-226, 244-266, 276-290; Viosca Knoll Blocks 473-476, 521,
                         522, 564, 565, 566, 609, 610, 654, 692-698, 734, 778.)
                                For the purpose of this stipulation, "five bottom areas" are defined as seagrass
                         communities; or those areas which contain biological assemblages consisting of such sessile
                         invertebrates as sea fans, sea whips, hydroids, anemones, ascidians, sponges, bryozoans, or
                         corals living upon and attached to naturally occurring hard or rocky formations with rough,
                         broken, or smooth topography; or areas whose lithotope favors the accumulation of turtles,
                         fishes, and other fauna.
                                Prior to any drilling activities or the construction or placement of any structure for
                         exploration or development on this lease, including, but not limited to, anchoring, well drilling,
                         and pipeline and platform placement, the lessee will submit to the Regional Director (RD)
                         a live bottom survey report containing a bathymetry map prepared utilizing remote sensing
                         techniques. The bathymetry map shall be prepared for the purpose of determining the
                         presence or absence of live bottoms which could be impacted by the proposed activity. This
                         map shall encompass such an area of the seafloor where surface disturbing activities, including
                         anchoring, may occur.
                                If it is determined that the live bottoms might be adversely impacted by the proposed
                         activity, the RD will require the lessee to undertake any measure deemed economically,
                         environmentally, and technically feasible to protect the pinnacle area. These measures may
                         include, but are not limited to, the following:

                                (a)      the relocation of operations; and

                                (b)       the monitoring to assess the impact of the activity on the live bottoms.

                Effectiveness of the Lease Stipulation

                    The sessile and pelagic communities associated with the crest and flanks of the pinnacle and hard-bottom
                features would be adversely impacted (i.e., have an expected impact level of low) by oil and gas activities
                resulting from the proposed action if such activities took place on or near these communities without the Live
                Bottom Stipulation. The low impact level from the proposed action without the stipulation is partly due to the
                widespread nature of the features in the pinnacle region and the comparatively low level of activity. The
                USDOI has recognized this problem for some years, and stipulations have been made a part of leases on blocks











                   11-18


                   on or near these biotic communities so that impacts from nearby oil and gas activities were mitigated to the
                   greatest extent possible. This stipulation does not prevent the recovery of oil and gas rescurces, but it does
                   serve to protect valuable and sensitive biological resources.
                       The analyses of the proposed actions in the Final EIS for Sales 131, 135, and 137 (USDOI, MMS, 1990a)
                   were done without the stipulations in place. A thorough analysis of the impacts of oil and gas activities as they
                   relate to the pinnacle region is presented there. The following is a summary of that analysis, which is hereby
                   incorporated by reference.
                       Activities resulting from the proposed action, particularly anchor damage to localized pinnacle areas, are
                   expected to have a high level of impact on some individuals at portions of the pinnacle trend environment,
                   since these activities have the potential to destroy some of the biological communities and damage one or
                   several individual pinnacles. The range of impacts that may potentially occur at the pinnacle region is low to
                   very low. The most potentially damaging of these are the impacts associated with mechanical damages that
                   may result from anchors. However, the action is judged to be infrequent because of the limited operations in
                   the vicinity of the pinnacles and the small size of many of the features. Potential impact levels from large oil
                   spills, blowouts, pipeline emplacement, muds and cuttings discharges, and structure removals are very low. The
                   frequency of impacts to the pinnacles is rare, and the severity is judged to be slight because of the widespread
                   nature of the features. The proposed action, without the benefit of the Live Bottom Stipulation, is expected
                   to have a low impact on the pinnacle region.
                       The pinnacle trend is known to exist as patchy regions within the general area of the eastern portion of
                   the CPA (Ludwick and Walton, 1957; Vittor and Associates, Inc., 1985; Brooks et al., 1989'. The stipulation
                   would force the operators to locate the individual pinnacles and associated communities that may be present
                   in the block. The stipulation requires that a survey be done to encompass the potential area of proposed
                   surface disturbance and that a bathymetry map be made from this survey. The bathymetry map depicts any
                   pinnacles in the vicinity of the proposed activity. (Since it is the pinnacles themselves and the habitat they
                   provide for various species that are sensitive to impacts from oil and gas activities, photo-documentationof the
                   identified pinnacles is not warranted.) The RD, through consultation with FWS, could then decide if pinnacles
                   in the trend would be potentially impacted and, if so, require any appropriate mitigative measures.
                       By identifying the individual pinnacles present at the activity site, the lessee would be directed to avoid
                   placement of the drilling rig and anchors on the sensitive areas. Thus, mechanical damage to the pinnacles
                   is eliminated when measures required by the stipulation are imposed. The stipulation does not address the
                   discharge of effluents near the pinnacles because the pinnacle trend is subjected to heavy natural sedimentation
                   and is at considerable depths. The rapid dilution of drill cuttings and muds will minimize the potential of
                   significant concentration of effluents on the pinnacles.

                   (3) Archaeolo*al Resource Stipuktion

                       The Archaeological Resource Stipulation has been placed on leases issued in the Gulf of Mexico Region
                   since 1974. The stipulation provides protection for prehistoric and historic archaeological resources by
                   requiring remote sensing surveys in areas designated to have a high probability for archaeological resources
                   and by requiring protection of archaeological resources discovered outside of the designated high probability
                   zones. The stipulation is included in the analysis of this proposed action.

                           (a)    "Archaeological resource" means any prehistoric or historic district, site, building,
                                  structure, or object (including shipwrecks); such term includes artifacts, records, and
                                  remains which are related to such a district, site, building, structure, or object (16 U.S.C.
                                  470w(5)). "Operations" means any drilling, mining, or construction or placement of any
                                  structure for exploration, development or production of the lease.

                           (b)    If the Regional Director (RD) believes an archaeological resource may exist in the lease
                                  area, the RD will notify the lessee in writing. The lessee shall then comply with
                                  subparagraphs (1) through (3).

                                  (1)     Prior to commencing any operations, the lessee shall prepare a :report, as
                                          specified by the RD, to determine the potential existence of any archaeological












                                                                                                                                11-19


                                       resource that may be affected by operations. The report, prepared by an
                                       archaeologist and geophysicist, shall be based on an assessment of data from
                                       remote-sensing surveys and of other pertinent archaeological and environmental
                                       information. The lessee shall submit this report to the RD for review.

                               (2)     If the evidence suggests that an archaeological resource may be present, the
                                       lessee shall either:


                                       (i)       Locate the site of any operation so as not to adversely affect the area
                                                 where the archaeological resource may be; or

                                       Qi)       Establish to the satisfaction of the RD that an archaeological resource
                                                 does not exist or will not be adversely affected by operations. This
                                                 shall be done by further archaeological investigation, conducted by an
                                                 archaeologist and a geophysicist, using survey equipment and
                                                 techniques deemed necessary by the RD.                A report on the
                                                 investigation shall be submitted to the RD for review.

                               (3)     If the RD determines that an archaeological resource is likely to be present in
                                       the lease area and may be adversely affected by operations, he will notify the
                                       lessee immediately. The lessee shall take no action that may adversely affect
                                       the archaeological resource until the RD has told the lessee how to protect it.

                        (c)    If the lessee discovers any archaeological resource while conducting operations on the
                               lease area, the lessee shall report the discovery immediately to the RD. The lessee
                               shall make every reasonable effort to preserve the archaeological resource until the RD
                               has told the lessee how to protect it.

               Effectiveness of the Lease Stipulation

                   Prehistoric archaeological resources would be slightly affected by oil and gas activities resulting from the
               proposed action if such activities took place within the zone of high probability for prehistoric resources.
               Historic archaeological resources would be adversely affected by oil and gas industry activities resulting from
               the proposed action if such activities took place within the zone of high probability for historic resources. The
               DOI has recognized its legal responsibilities for protection of archaeological resources on the Gulf of Mexico
               OCS, and since 1974 stipulations have been made a part of leases on blocks within the Gulf of Mexico Region.
               The stipulation does not prevent the recovery of oil and gas resources, but it does provide a mechanism to
               protect our Nation's prehistoric and historic OCS archaeological resources.
                   The Archaeological Resource Stipulation shall assure MMS compliance with Federal laws and regulations
               requiring protection of archaeological resources. The National Historic Preservation Act of 1966, as amended,
               requires each Federal agency to establish a program to locate, inventory, and nominate to the Secretary all
               properties under the agency's ownership or control that appear to qualify for inclusion on the National
               Register. Section 2(a) of Executive Order 11593 provides that Federal agencies shall locate, inventory, and
               nominate to the Secretary of the Interior all sites, buildings, districts, and objects under their jurisdiction or
               control that appear to qualify for listing on the National Register of Historic Places. Section 11(g)(3) of the
               OCSLA, as amended, states that "such exploration (oil and gas) will not ... disturb any site, structure, or object
               of historical or archaeological significance." Because of these laws and regulations, the withdrawal of the
               Archaeological Resource Stipulation would not relieve the MMS of its legal responsibility to protect OCS
               archaeological resources.
                   The analyses of the proposed actions in the Final EIS for Sales 131, 135, and 137 (USDOI, MMS,1990a)
               were presented without the stipulations in place. A thorough analysis of the impacts of oil and gas activities
               as they relate to archaeological resources is presented there. The following is a summary of that analysis, which
               is incorporated by reference.











                    11-20


                        The purpose of the stipulation is to provide a mechanism to protect OCS archaeological resources from
                    adverse effects due to oil and gas exploration and development. Several impact-producing factors may threaten
                    prehistoric and/or historic archaeological resources. The placement of drilling rigs, production platforms,
                    pipelines, and anchoring could destroy artifacts or disrupt the provenience and stratigraphic context of artifacts,
                    sediments, and paleoindicators from which the scientific value of the archaeological resource is derived. 01
                    spills could destroy the ability to date prehistoric sites by radiocarbon dating techniques. Dredging new channels
                    and maintaining current channels could impact a historic shipwreck. Ferromagnetic debris associated with OCS
                    oil and gas activities would tend to mask magnetic signatures of significant historic archaeological resources.
                        The stipulation is the agency's effort to comply with existing Federal laws and regulations. It provides a
                    mechanism for the protection of the Nation's OCS archaeological resources. Remote-sensing surveys mandated
                    in the stipulation will serve to protect archaeological resources from oil and gas activities resulting from the
                    proposed action by identifying the location of the resources. Without the stipulation in plao-, the agency would
                    still be responsible for protecting the Nation's OCS archaeological resources. Remote-sensing surveys would
                    still be required to ensure compliance with existing laws and regulations.

                    (4) Military Areas Stipulation

                        The proposed Military Areas Stipulation has been applied to blocks in military warning and water test
                    areas in past lease sales in the Central Gulf and may be included, at the option of the Secretary, in all leases
                    resulting from this proposed action. The military has recommended utilizing the stipulation on all leasing
                    operations within their warning areas.

                        The stipulation reads as follows:
                                                            Military Areas Stipulation No. 1

                            Hold and Save Harmless


                                   Whether compensation for such damage or injury might be due under a theory of strict
                            or absolute liability or otherwise, the lessee assumes all risks of damage or injury to persons
                            or property, which occur in, on, or above the Outer Continental Shelf (OCS), to any persons
                            or to any property of any person or persons who are agents, employees, or invitees of the
                            lessee, its agents, independent contractors, or subcontractors doing business with the lessee
                            in connection with any activities being performed by the lessee in, on, or above tlie OCS, if
                            such injury or damage to such person or property occurs by reason of the activities of any
                            Agency of the United States Government, its contractors or subcontractors, or any of its
                            officers, agents or employees, being conducted as a part of, or in connection with, the
                            programs and activities of the command headquarters listed in Table 11-1.
                                  Notwithstanding any limitation of the lessee's liability in Section 14 of the lease, the
                            lessee assumes this risk whether such injury or damage is caused in whole or in part by any
                            act or omission, regardless of negligence or fault, of the United States, its contractors or
                            subcontractors, or any of its officers, agents, or employees. The lessee further agrees to
                            indemnify and save harmless the United States against all claims for loss, damage, or injury
                            sustained by the lessee, or to indemnify and save harmless the United States against all claims
                            for loss, damage, or injury sustained by the agents, employees, or invitees of the lessee, its
                            agents, or any independent contractors or subcontractors doing business with the lessee in
                            connection with the programs and activities of the aforementioned military installation,
                            whether the same be caused in whole or in part by the negligence or fault of the United
                            States, its contractors, or subcontractors, or any of its officers, agents, or employees and
                            whether such claims might be sustained under a theory of strict or absolute liability or
                            otherwise.











                                                                                                                 11-21

                                                           Table II-1


                                                        Military Contacts

                                                     Central Gulf of Mexico

                        Warnine Areas                                            Command Headquarters



                        *W-155A and W-155B                                       Fleet Area Control & Surveillance
                        (for operational control)                                 Facility (FACSFAC)
                                                                                 Naval Air Station
                                                                                 Pensacola, Florida 32508
                                                                                 Telephone: (904) 452-2735/4671

                        W-92                                                     Naval Air Station
                                                                                 Air Operations Department
                                                                                 Air Traffic Division/Code 52
                                                                                 New Orleans, Louisiana 70146-5000
                                                                                 Telephone: (504) 393-3100/3101

                        W-453                                                    159th Tactical Fighter Group (ANG)
                                                                                  NAS NOLA
                                                                                 New Orleans, Louisiana 70143
                                                                                 Telephone: (504) 391-8612/8621

                        Eglin Water Test Areas 1-5                               Air Force Development Test Center
                                                                                 3246th Test Wing/CCU
                                                                                 Eglin AFB, Florida 32542
                                                                                 Telephone: (904) 882-8963

                                                     Western Gulf of Mexico

                        Warning Areas                                            Command Headquarters

                        W-228                                                    Chief, Naval Air Training
                                                                                 Naval Air Station
                                                                                 Corpus Christi, Texas 78419-5100
                                                                                 Telephone: (512) 939-3927/3902

                        W-602                                                    Headquarters SAC/DONO
                                                                                 Deputy Chief of Staff
                                                                                 Operations Headquarters
                                                                                  Strategic Air Command
                                                                                 Offutt AFB, Nebraska 68113-5001
                                                                                 Telephone: (402) 294-3103/3450 or
                                                                                 Scheduling: (402) 294-2334

                        *W-155A and W-155B                                       Chief, Naval Air Training
                        (for agreement)                                          Naval Air Station
                                                                                 Corpus Christi, Texas 78419-5100
                                                                                 Telephone (512) 939-3927/3862











                     11-22


                              Electromagnetic Emissions

                                    The lessee agrees to control its own electromagnetic emissions and those of its agents,
                              employees, invitees, independent contractors or subcontractors emanating from individual
                              designated defense warning areas in accordance with requirements specified by the
                              commander of the command headquarters listed in Table 11-1 to the degree necessary to
                              prevent damage to, or unacceptable interference with Department of Defense flight, testing,
                              or operational activities, conducted within individual designated warning areas. Necessary
                              monitoring control, and coordination with the lessee, its agents, employees, invitees,
                              independent contractors or subcontractors, will be affected by the commander of the
                              appropriate onshoremilitary installation conducting operations in the particular warning area;
                              provided, however, that control of such electromagnetic emissions shall in no instance prohibit
                              all manner of electromagnetic communication during any period of time between a lessee, its
                              agents, employees, invitees, independent contractors or subcontractors and onshore facilities.

                              Operational

                                    The lessee, when operating or causing to be operated on its behalf, boat, ship, or aircraft
                              traffic into the individual designated warning areas, shall enter into an agreement with the
                              commander of the individual command headquarters listed in Table II-1, upon utilizing an
                              individual designated warning area prior to commencing such traffic. Such an agreement Will
                              provide for positive control of boats, ships, and aircraft operating into the warning areas at
                              all times.


                     Effectiveness of the Lease Stipulation

                         The hold harmless section of the proposed Military Areas Stipulation serves to protect the U.S.
                     Government from liability in the event of an accident involving the lessee and military activities. The actual
                     operations of the military and the lessee and its agents will not be affected. The electromagnetic emissions
                     section of the proposed stipulation requires the lessee and its agents to reduce and curtail the use of radio, CB,
                     or other equipment emitting electromagnetic energy within some areas. This serves to reduce the impact of
                     oil and gas activity on the communications of military missions and reduces the possible effects of
                     electromagnetic energy transmissions on missile testing, tracking, and detonation.
                         The operational section requires notification to the military of oil and gas activity to -take place within a
                     military use area. This allows the base commander to plan military missions and maneuvers that will avoid the
                     areas where oil and gas activities are taking place or to schedule around these activities. Prior notification
                     helps reduce the potential impacts associated with vessels and helicopters traveling unannounced through areas
                     where military activities are underway.
                         The proposed Military Areas Stipulation reduces potential impacts, particularly in regards to safety, but
                     does not reduce or eliminate the actual physical presence of oil and gas operations in areas where military
                     operations are conducted. The reduction in potential impacts resulting from this stipulation would make
                     multiple-use conflicts most unlikely. Without the stipulation, some potential conflict is likely. The best
                     indicator of the overall effectiveness of the stipulation may be that there has never been an accident involving
                     a conflict between military operations and oil and gas activities.

                     (5) Notices to Lessees and Letters to Lessees

                         Notices to Lessees and Operators (NTL's) are formal documents that provide clarification, description, or
                     interpretation of a regulation or OCS standard; provide guidelines on the implementation of a special lease
                     stipulation or regional requirement; provide a better understanding of the scope and meaning of a regulation
                     by explaining MMS interpretation of a requirement; or transmit administrative informati.on such as current
                     tele phone listings and a change in MMS personnel or office address. A detailed listing of current and effective
                     Gulf of Mexico NTL's was published in the Federal Register on May 16, 1991 (56 FR 22735 -22737. The MMS
                     publishes an updated NTL listing annually in the Federal Register.











                                                                                                                                   11-23

                     The MMS also conveys important information by way of Letters to Lessees and Operators (LTL's) and
                Information to Lessees and Operators (ITL's). These documents further clarify or supplement operational
                guidelines. Separate Regional mailings and the EIS process have served as the vehicles for communicating
                previously issued NTI:s, LTI:s, and ITL's.
                2. Alternative B - The Proposed Action Excluding the Blocks Near
                     Biologically Sensitive Topographic Features

                     This alternative, offered for the Secretary's consideration, would protect valuable offshore biological
                resources. It affects the biologically sensitive banks (topographic features) of the Central Gulf.
                     All of the blocks included in the deletion alternative are also the blocks that are covered by the proposed
                Topographic Features Stipulation (discussed in Section II.A.Lc.(1)). The Secretary may choose to adopt only
                a part of this alternative in order to promote the environmental protection policies of the Department.

                a. Description

                     This alternative would offer all the blocks offered by the proposal except the 62 unleased blocks (Figures
                IM and 11-2) of the total 167 blocks (these blocks are listed in Appendix A) affected by the proposed
                Topographic Features Stipulation. These blocks are on or near enough to biologically sensitive areas of the
                topographic features of the CPA so that activities resulting from the proposed action could have a high
                probability of impacting these biota. These blocks represent about 1.2 percent of the 5,194 blocks to be offered
                in the Central Gulf. It is estimated that the proposal could result in the discovery and production of 0.14 BBO
                and 1.40 tcf of gas during the time period 1993-2027. There are no areas deferred from the CPA- For more
                information describing the proposed action and alternatives, see Section I.B.2.
                     The analyses of impacts summarized below and described in detail in Section IV.D.Lb. are based on a
                development scenario (Base Case) formulated to provide a set of assumptions and estimates on the amounts,
                locations, and timing for OCS exploration, development, and production operations and facilities, both offshore
                and onshore. These are estimates only and not predictions of what will happen as a result of holding the
                proposed sale. A detailed discussion, with tables, of the development scenario and major related impact-
                producing factors is included in Section W.A. The following are the major estimates of activities and associated
                impact-producing factors assumed for proposed Sale 142 (Base Case). These estimates and factors were
                utilized in the impact analyses.

                         (1)       During the exploration phase, 1994-2004, there will be 340 wells drilled, resulting in
                                   the following:

                                   -        the generation of 2.42 MMbbl of drilling mud and 0.63 MMbbI of drill
                                            cutting wastes, 18 percent of which will be disposed of onshore;

                                   -        offshore air emissions from well drilling operations of 330 tons of total
                                            suspended particulate matter, 95 tons of total hydrocarbons, 384 tons of
                                            sulphur oxides, 877 tons of carbon monoxide, and 3,288 tons of nitric oxides;

                                   -        6,600 service vessel trips and 23,000 helicopter landings;

                                   -        disturbance from rig emplacements of 144 ha of ocean bottom; and

                                   -        the likelihood of 1 blowout (Section IV.A_.d.(8)).













                                                                                                                                                                                          t4


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                                                                                           C,:


                                                            569   570                                              WEST CA 4ER )N
                                               A-312                                      W                                                        EAST AWERON
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                                                      aD    590   589
                                               A-327

                                                                                           V)
                                                             59            29 FATHOM
                                              A-332
                                                       A-330


                                       A-346 A-347
                                                    A-348                                                     7LT,@
                                                                  614

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                                                                 633
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                                                                               636
                                                                  634    635         637   638

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                                                              371
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                                       RANKIN      A-390            54,                                        61
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                                                               42             44   145  U,\                                                          \\\\I
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                                                                                                             I-    rN

                                       Unleased Block
                           f7E]                                                                                                                 @ST

                                                                                                            r77
                                                                                     650\                   L, 61













                 Figure H-1. Location and Lease Status of Blocks Affected by Alternative B (West Louisiana).


















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                                                                                                                                                                                                                                                                                                                                                                                         Leased Block


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                                                                                                                                                                           LL I        V
                                                                                                                                                                      =f=FiW
                                                                                                                                                                                                                                                                                                                                                                                    4.















                                                Figure 11-2. Location and Lease Status of Blocks Affected by Alternative B (East Louisiana).











                   11-26


                            (2)       During the development phase, 1995-2017, there will be 130 oil wells and 120 gas
                                      wells drilled, resulting in the following:

                                      -        the generation of 1.69 MMbbl of drilling mud and 0.358 MMbbl of drilling
                                               cutting wastes, a small amount of which will be disposed of onshore;

                                      -        offshore air emissions from well drilling operations of 162 tons of total
                                               suspended particulate matter, 47 tons of total hydrocarbons, 189 tons of
                                               sulphur oxides, 430 tons of carbon monoxide, and 1,611 tons of nitric oxides;

                                      -        4,800 service vessel trips and 17,000 helicopter landings;

                                      -        the disturbance from fixed structure emplacements of 48 ha of ocean bottom;
                                               and

                                      -        the likelihood of 1 blowout (Section IV.A-2.d.(8)).

                            (3)       During the production phase, 1995-2026, 0.14 BBO of oil and 1.40 tcf of gas will be
                                      produced from 29 platform complexes and one floating production system, resulting
                                      in the following:

                                      -        the open-water discharge of 283 MMbbl of produced water;

                                      -        the onshore disposal of 34 MMbbl of produced waters and 69,000 bbl of
                                               produced sands that were generated offshore;

                                      -        air emissions of 124 tons of total suspended particulate matter, 19J75 tons
                                               of total hydrocarbons, 88 tons of sulphur oxides, 6,590 tons of carbon
                                               monoxide, and 50,592 tons of nitric oxides;

                                      -        6,300 service vessel trips and 328,000 helicopter trips;

                                      -        the removal of 120 ha of commercial fishing area (peak year estimate); and

                                      -        the likelihood of 2 blowouts (Section IV.A.2.d.(8)).

                           (4)        During   platform removal operations, which will occur the year after production
                                      ceases, 20 platforms will be removed using explosives.

                           (5)        The transportation of gas and oil will require the following:

                                               the construction of 240 krn of gathering pipelines that will connect with
                                               existing trunklines prior to landfall, resulting in the disturbance of 77 ha of
                                               bottom and the displacement of 320,000 m       3of sediment;

                                               77 barge trips carrying oil to 8 existing shore terminals along the Texas and
                                               Louisiana coasts; and

                                               2 shuttle tanker trips carrying oil to Mississippi River terminals.

                           (6)        Support activity will result in the following:

                                               No new major onshore support or processing facility construction is expected;
                                               existing OCS-related facilities will be used, with sale-related activities utilizing











                                                                                                                                 11-27


                                           about 3 percent, on the average, of the capacities of the onshore
                                           infrastructure.


                                           the use of 18 navigation channels, 7 major channels in Louisiana will be
                                           maintenance dredged periodically and one deepened to support vessel traffic;

                                           56 million liters of bilge water discharged in coastal waters from service
                                           vessels traveling to 28 existing bases;

                                           206,000 helicopter coastal crossings to reach 27 helicopter hubs; and

                                           air emissions from service vessels and helicopters of 680 tons of total
                                           suspended particulate matter, 495 tons of total hydrocarbons, 177 tons of
                                           sulphur oxides, 1,466 tons of carbon monoxide, and 9,264 tons of nitric
                                           oxides.


                         (7)      TWenty-one crude oil spills greater than 1 and less than or equal to 50 bbl, one spill
                                  between 50 and 1,000 bbl, and one spill of 1,000 bbl or greater are assumed to occur.
                                  The large spill is projected to be 6,500 bbl and has a 16 percent chance of land
                                  contact.


                         (8)      Fewer than 10 crude oil spills greater than one and less than 50 bbl are assumed to
                                  occur from onshore support activities.

                         (9)      Total employment from all activities associated with the exploration, development,
                                  and production of oil and gas generated as a result of Sale 142 is 58,500 personnel,
                                  45 percent of which will be directly employed.

                    It should be noted that the assumptions and estimates for Alternative B are the same as in the Base Case
                of Alternative A- Alternative B is essentially Alternative A minus 58 widely scattered blocks (representing
                about 1.1 percent of the blocks to be offered under Alternative A). Due to the scattered nature of the blocks
                that would not be offered by this alternative, resource estimates for Alternative B do not differ from those
                estimated for Alternative A. To the extent that adoption of Alternative B, by reducing the blocks available
                for leasing, reduces the activities resulting from the leasing, these assumptions and estimates will be similarly
                reduced. For instance, it may be reasonable to assume that one oil or gas field may be present in one or more
                of the blocks not offered under Alternative B. As discussed in Section IV.A_, not conducting exploration or
                development activities on that field (because the blocks are not part of the sale area under this alternative)
                could possibly result in the following activities not happening (which might otherwise occur under Alternative
                A): 2-4 exploration wells with the disturbance of 1.5 ha of seafloor per well; 1 platform with the disturbance
                of 2 ha of seafloor (4 ha in water deeper than 1,500 ft); 12 development wells from that platform; 8 km of
                gathering pipeline for that platform; no anchoring, pipeline burial, or sediment disturbance will occur in the
                block; no use of service vessels or helicopters to and from that block will be required; no discharges of drilling
                muds (7,134 bbl per exploration well, 6,749 bbl per development well), drill cuttings (1,853 bbl per exploration
                well, 1,430 bbl per development well); no discharge of produced waters (450 bbl per oil well per day; 68 bbl
                per gas well per day); no air emissions; and no chance for oil and gas industry-related accidents.
                     The primary difference between Alternative A (with the proposed Topographic Features Stipulation) and
                Alternative B (which excludes the blocks affected by that stipulation) is that under Alternative B oil and gas
                activities would be completely excluded from taking place within the blocks which, under Alternative A,
                activities could take place (although with certain restrictions in certain portions of the blocks). Figure 111-5
                shows a topographic feature with its attendant proposed No Activity Zone, 1 Mile Zone, and 3 Mile Zone.
                Under Alternative A, all those blocks containing any of those zones could be leased, although no oil and gas
                activities would be permitted in the No Activity Zone and activities would be restricted in the I and 3 Mile












                 11-28


                 Zones. Under Alternative B, none of those blocks containing any of those zones would be leased, thus
                 precluding any oil and gas activities anywhere in those blocks.

                 b. Summary of Impacts

                     The following summarizes the detailed impact analyses of Section IV.D.Lb. It should be emphasized that
                 these are impact summaries and that the reader should refer to Section IV.D.Lb. for detailed information
                 regarding particular resources. Table S-3 compares the impacts of Alternatives A-C and. the cumulative
                 impacts on each resource category estimated as a result of the various scenarios.
                     To facilitate the analyses, the Federal offshore area is divided into subareas. The CPA. is comprised of
                 four subareas (C-1, C-2, C-3, and C4) and the coastal region is divided into four coastal subareas (C-1, C-2,
                 C-3, and C4). These subareas are delineated on Figure IV-1.
                     This alternative is offered for the Secretary's considerationto protect valuable offshore biological resources.
                 It affects the biologically sensitive banks (topographic features) of the Central Gulf.
                     Given the size of the area available for lease under Alternative A, it is reasonable to assume that the
                 removal of 1.2 percent of the area probably will not significantly change the projected level of activity (i.e.,
                 numbers of wells, platforms, vessel trips, etc. (Table IV-1)) projected under that alternative. The only
                 differences are that under Alternative B no activity will take place in the deletion areas. The assumption that
                 the levels of activity for Alternative B are virtually identical to those projected for Alternative A indicates that
                 the impacts expected to result will be very similar to those described under Alternative A (S,ection IV.D.La).
                 The areas that would not be offered under Alternative B make up only a small portion of the CPA, and with
                 the exception of topographic features, only contain comparatively small amounts, if any, of the resources
                 analyzed in this document. Therefore, the regional impact levels for all resources are estimated to be identical
                 to those described under Alternative A- However, there are some localized changes in the impacts as described
                 below.


                 Coastal Resources


                     Coastal resources include beaches, seagrass beds, salt and fresh marshes, and estuaries. The beaches serve
                 as recreational sites in addition to storm protection and erosion control areas. The marshes and estuaries
                 support numerous commercially and recreationally important fish and wildlife species. The primary impact-
                 producing factors of concern for these environmental resources are contact by oil spills and disturbance from
                 the emplacement of pipelines or the dredging of channels.
                     The areas that would be deleted from the proposed sale with the selection of Alternative: B are scattered
                 across the CPA shelf far from the coastline. All of the areas available for deletion, with one exception, are
                 located over 115 krn (70 mi) from shore (Sackett Bank with a 2 1/4 block deletion area is located about 30 kin
                 (18 mi) from the mouth of the Mississippi River). Considering the assumption that the estimated level of
                 activity will not change from that projected for Alternative A and the substantial distances from the deletion
                 areas to coastal resources, it is extremely unlikely that selection of Alternative B would have any influence on
                 the impacts estimated for Alternative A.

                 Conclusion


                     The impacts on the following coastal resources are estimated to be the same as those estimated under
                 Alternative A-    coastal barriers; wetlands; coastal and estuarine water quality; air quality; Alabama,
                 Choctawhatchee, and Perdido Key beach mice; nonendangered and nonthreatened coastal and marine birds;
                 endangered and threatened marine birds; recreational beach use; and population, labor, and employment.











                                                                                                                               11-29


                Offshore Resources

                    Deletion of this area would preclude drilling operations and associated activities from occurring within the
                62 affected blocks. It, would further eliminate the threat of damage from drilling discharges, anchoring, or
                platform/pipeline emplacement and removal related to the exploration and development of this area. The
                following analyses deal specifically with the sensitive resources that may exist in the deletion area and for which
                there might be a change in impacts with the selection of Alternative B. Live-bottom areas (Pinnacle Trend),
                deep-water benthic communities, and archaeological resources are not located in or near the area, so there
                would be no change in the impact level projected under Alternative A- Commercial fisheries and recreational
                marine fishing would also remain as under Alternative A.

                    Topographic Features

                    Essentially, oil and gas operations within the blocks that fall within 3 nmi of the 85-m isobath of the 16
                banks of the Central Gulf (and 2 banks of the Western Gulf that are within 3 nmi of the Central Gulf) are
                considered potential sources of impact to biota of those banks that could be harmed by oil and gas activities.
                The biological resources of the topographic features are considered very sensitive to potential impacts due to
                oil and gas operations; however, topographic features in the Central Gulf are usually the surface expressions
                of salt domes, which are often associated with oil and gas reserves. The recovery of such reserves, the extent
                of which is unknown at this time, would be prevented by the adoption of this alternative. It is noted that 105
                of the 167 blocks affected are already leased. This deletion alternative is presented in order to fully protect
                the biological resources inhabiting the crests of the topographic features.
                    This alternative, if adopted, would prevent any oil and gas activity whatsoever in the affected blocks (except
                for pipeline construction, which would be regulated through the normal pipeline permitting procedures); thus,
                it would eliminate any impacts to the biota of the area from oil and gas activities, which otherwise would be
                conducted within the blocks. However, because of the operation of the proposed Topographic Features
                Stipulation, which is included in the analysis of Alternative A (Section II.Al.c.(l)), the impact levels to the
                topographic features will be essentially the same for both Alternative A and Alternative B.

                    Conclusion


                    The activities assumed for Alternative B are expected to cause little to no damage to the physical integrity,
                species diversity, or biological productivity of the habitat of the topographic features of the Gulf of Mexico.
                Small areas of 5-10 rn2 would be impacted, and recovery from this damage to pre-impact conditions is expected
                to take less than 2 years, probably on the order of 24 weeks. Selection of Alternative B would preclude oil
                and gas operations in the unleased blocks (62 of 167) affected by the proposed Topographic Features
                Stipulation.

                    Marine Water Quality

                    The impact-producing factors leading to water quality degradation resulting from offshore OCS oil and gas
                operations include the resuspension of bottom sediments through exploration and development activities,
                pipeline construction, and platform removal operations; the discharge of deck drainage, sanitary and domestic
                wastes, formation waters (produced waters), and drilling fluids (muds and cuttings);                and accidental
                hydrocarbon discharges due to spills, blowouts, or pipeline leaks. Routine operational discharges may degrade
                water quality with high impacts occurring within a few meters to tens of meters from the source. These impacts
                decrease to very low with distance (500-1,000 in) from the source. Accidental oil spills may degrade water
                quality somewhat, changing the measurements from background levels only in a very limited area close to the
                source. Adoption of this alternative would preclude impacts associated with routine exploration and production
                activities in the area not offered. It would not eliminate the threat of degradation from those OCS activities
                occurring outside the area not offered. However, because the area not offered is a small portion of the entire











                  11-30


                  area offered for leasing under either Alternative A or Alternative B, the regional impact level will be reduced
                  by only that small amount, assuming that oil and gas activities would be reduced proportionally.

                       Conclusion


                       Selection of Alternative B would eliminate potential impacts on very localized areas contained in the
                  deletion area, but this would not be significant enough to change the regional impact level. on marine water
                  quality as projected under Alternative A-

                       Marine Mammals, Marine Turtles, and the Gulf Sturgeon

                       As benthic feeders, adult loggerhead, green, hawksbill, and Kemp's ridley sea turtles are unlikely to occur
                  in the proposed deletion area because the topographic features in the CPA and WPA are at depths in excess
                  of 300 in, which is the lower limit of the feeding habitat for these species. However, the pelagic stages of all
                  sea turtles could occur in the vicinity of any of these areas. Sperm whales have been sighted near topographic
                  features in the CPA and several of the more common small marine mammals--Stenella, Kogia, and Grampus--
                  could be expected in the vicinity of topographic features because of the presence of prey species. Sea turtles
                  and marine mammals could be impacted by off and gas activities in this area by contact with or ingestion of
                  oil, collision with vessels, entanglement in or ingestion of debris generated from platforms, or physical/acoustic
                  disturbances (drilling, and structure placement and removal). Not offering this area would eliminate all impacts
                  to sea turtles and marine mammals that would otherwise occur from proposed action-related oil and gas
                  operations within the blocks not offered. If the area is not offered, impacts to marine mammals and sea turtles
                  will not change from those of the proposed action because of the comparatively low level of oil and gas activity
                  proposed in the area.

                       Conclusion


                       Selection of Alternative B would eliminate potential impacts on endangered species and marine mammals
                  in or near the area that would not be offered under this alternative. This slightly smaller number of blocks to
                  be offered is not substantial enough to change the regional impacts on these resources as projected under
                  Alternative A. These impacts are as follows: marine mammals and marine turtles - sublethal effects that are
                  chronic and could result in persistent physiological or behavioral changes; the Gulf sturgeon - sublethal effects
                  that could cause short-term physiological or behavioral changes.

                  3. Alternative C - No Action

                  a. Description

                       The alternative is equivalent to cancellation of a sale scheduled for a specific timeframe on the approved
                  5-year OCS Oil and Gas Leasing Schedule. Sales in the Central Gulf are scheduled on an annual basis. By
                  canceling the proposed sale, the opportunity is postponed or foregone for development of the estimated 0.14
                  B130 and 1.40 tcf of gas that could have resulted from proposed Sale 142 in the Central Gulf

                  b. Summary of Impacts

                       If Alternative C is selected, all impacts, positive and negative, associated with the proposed action would
                  be canceled. This alternative would therefore result in no effect on the sensitive resources and activities
                  discussed in Section IV.D.l.a. The incremental contribution of the proposed action to cumulative effects would
                  also be foregone, but such effects from other activities, including other OCS sales, would remain. One
                  contribution to impacts that could increase is oil spill risk due to the importation of foreign oil to replace the
                  resources lost through cancellation of the proposed action.












                                                                                                                                  11-31


                    Alternative energy strategies that could provide replacement resources for lost domestic OCS oil and gas
                production include energy conservation; conventional oil and gas supplies; coal; nuclear power; oil shale; tar
                sands; hydroelectric power; solar and geothermal energy; and imports of oil, natural gas, and LNG. These are
                discussed in some detail in Appendix D. The energy equivalents that may be required from several alternative
                energy sources, should this lease sale be permanently canceled, are shown on Table D-8 and are based on the
                resources estimated by MMS to be produced as a result of the proposed action. For the purpose of clarity,
                this table has separately identified each potential alternative source of energy regarding substitution
                requirements. It is unlikely, however, that there would be a single choice between these alternative sources,
                but instead, some combined effort to explore and develop further many or an of these forms as a substitute
                for OCS oil and gas production.

                4. Comparison of Alternatives

                    Table S-3 provides a comparison and summary of the impacts of the proposed action (Alternative A), the
                proposed action excluding the blocks near biologically sensitive topographic features (Alternaiive B), no action
                (Alternative C), and the cumulative analyses for proposed Sale 142.

                B. PROPOSED WESTERN GULF SALE 143

                1. Alternative A - The Proposed Action

                a. Description

                    Proposed Western Gulf Sale 143 is scheduled to be held in August 1993 and will offer all unleased blocks
                within the WPA, except for two biologically sensitive blocks. The blocks deferred from the proposed action,
                because of the environmentally sensitive nature of the biological communities located on these blocks, are High
                Island Area, East Addition, South Extension Block A-375 (East Flower Garden Bank) and High Island Area,
                East Addition, South Extension Block A-398 (West Flower Garden Bank). It is estimated that the proposal
                could result in the discovery and production of 0.05 BBO and 0.74 tcf of gas during the time period 1993-2027.
                There are three alternatives to the proposed action. The alternatives are to delete biologically sensitive areas
                near topographic features and offer the remaining acreage, delete a 340-block naval operations area off Corpus
                Christi, Texas, and offer the remaining acreage, or to take no action (cancel the sale). For more information
                describing the proposed action and alternatives, see Section I.
                    The analyses of impacts summarized in this section and presented in detail in Section IV.D.2. are based
                on a development scenario (Base Case) formulated to provide a set of assumptions and estimates on the
                amounts, locations, and timing for OCS exploration, development, and production operations and facilities, both
                offshore and onshore. These are estimates only and not predictions of what will happen as a result of holding
                the proposed sale. A detailed discussion, with tables, of the development scenario and major related impact-
                producing factors is included in Section IV.A_ The following are the major estimates of activities and associated
                impact-producing factors assumed for proposed Sale 143 (Base Case). These estimates and factors were
                utilized in the impact analyses.

                         (1)      During the exploration phase, 1994-2004, there will be 210 wells drilled, resulting in
                                  the following:

                                           the generation of 1.50 MMbbI of drilling mud and 0.39 MMbbl of drill
                                           cutting wastes, about 18 percent of which will be disposed of onshore;

                                           offshore air emissions from well drilling operations of 204 tons of total
                                           suspended particulate matter, 59 tons of total hydrocarbons, 237 tons of
                                           sulphur oxides, 542 tons of carbon monoxide, and 2,031 tons of nitric oxides;











                 11-32



                                           4, 050 service vessel trips and 14,200 helicopter landings;

                                           disturbance from rig emplacements of 83 ha of ocean bottom; and

                                           the likelihood of 1 blowout


                         (2)      During the development phase, 1995-2016, there will be 50 oil wells and 60 gas wells
                                  drilled, resulting in the following:

                                           the generation of 0.74 MMbbl of drilling mud and 0.157 MMbbl of drilling
                                           cutting wastes, a small amount of which will be disposed of onshore;

                                           offshore air emissions from well drilling operations of 94 tons of total
                                           suspended particulate matter, 27 tons of total hydrocarbons, 109 tons of
                                           sulphur oxides, 248 tons of carbon monoxide, and 9,31 tons of nitric oxides;

                                           2,120 service vessel trips and 7,425 helicopter landings;

                                           the disturbance from fixed structure emplacements of 10 ha of ocean bottom;
                                           and

                         (3)      During the production phase, 1995-2026, 0.05 BBO of oil and 0.74 tcf of gas will be
                                  produced from 8 platform complexes and two floating production systems, resulting
                                  in the following:

                                  -        the open-water discharge of 126 MMbbl of produced water;

                                  -        24,000 bbl of produced sands disposed of onshore;

                                  -        offshore air emissions from platforms of 42 tons of total suspended
                                           particulate matter, 6,500 tons of total hydrocarbons, 30 tons of sulphur
                                           oxides, 2,234 tons of carbon monoxide, and 17,150 tons of nitric oxides;

                                  -        2,086 service vessel trips and 109,000 helicopter landings;

                                  -        the removal of 15 ha of commercial fishing area (peak year estimate); and

                                  -        the likelihood of 1 blowout.

                         (4)      During platform removal operations, which will occur the year after production ceases
                                  3 platforms will be removed using explosives.

                         (5)      The transportation of gas and oil will require the following:

                                           the construction of 80 km of gathering pipelines that will connect with
                                           existing trunklines prior to landfall, resulting in the disturbance of 26 ha of
                                           bottom and the displacement of 40,000    M3  of sediment;
                                           9 barge trips carrying oil to 3 existing shore terminals; and

                                           66 shuttle tanker trips carrying oil to four Texas and two Louisiana terminals.











                                                                                                                                    11-33


                          (6)       Support activity will result in the following:

                                             No new major onshore support or processing facility construction is expected;
                                             existing OCS-related facilities will be used, with sale-related activities utilizing
                                             about 3 percent, on the average, of the capacities of the onshore
                                             infrastructure.

                                    -        the use of 15 navigation channels (less than 1 percent), that win be
                                             maintenance dredged periodically and one deepened to support vessel traffic,

                                    -        26 million liters of bilge water discharged in coastal waters from service
                                             vessel traffic to 27 existing bases;

                                    -        73,000 helicopter coastal crossings to reach 20 helicopter hubs; and

                                    -        air emissions from service vessels and helicopters of 211 tons of total
                                             suspended particulate matter, 154 tons of total hydrocarbons, 56 tons of
                                             sulphur oxides, 470 tons of carbon monoxide, and 2,857 tons of nitric oxides.

                          (7)       Eight crude oil spills greater than 1 and less than or equal to 50 bbl are projected to
                                    occur, but none will reach land.

                          (8)       Fewer than 10 crude oil spills greater than one and less than 50 bbl are assumed to
                                    occur from onshore support activities.

                          (9)       Total employment from all activities associated with the exploration, development,
                                    and production of oil and gas generated as a result of Sale 143 is 24,000 personnel,
                                    45 percent of which will be directly employed.

                  b. Summary of Impacts

                      The following summarizes the detailed impact analyses of Section IV.D.2.a. It should be emphasized that
                  these are impact summaries and that the reader should refer to Section IV.D.2.a. for detailed information
                  regarding particular resources. Note that these summaries are limited to the impact of the proposed action
                  (Base Case). The impacts under the Cumulative Analysis are assessed in Section IV.D.2.d. and are not
                  summarized here. Table S-4 compares the impacts of Alternatives A-D and the cumulative impacts on each
                  resource category estimated as a result of the various scenarios.
                      The following impact analyses are for the proposed action and include the following potential stipulations
                  as part of the proposed action: the Topographic Features Stipulation, the Live Bottom Stipulation, the
                  Archaeological Resource Stipulation, and the Military Areas Stipulation. The analyses to follow presume fun
                  compliance with the proposed stipulations.
                      To facilitate the analyses, the Federal offshore area is divided into subareas. The WPA is comprised of
                  three subareas (W-1, W-2, and W-3) and the coastal region is divided into two coastal subareas (W-1, and W-
                  2). These subareas are delineated on Figure IV-1.

                  Sensitive Coastal Environments


                      Coastal Barrier Beaches (Section IVD.2.a.(1)(a))

                      Oil-spill contact to a barrier island could result in erosional changes in the barrier if cleanup operations
                  removed large quantities of sand. Because of the very low probability of occurrence of and contact from either











                 11-34


                 an offshore or onshore spill of 1,000 bbI or greater, however, it is assumed that no contact from a spill will
                 occur. Although several spills greater than 1 and equal to or less than 50 bbI are assumed to occur in coastal
                 areas of the WPA and contact barrier landforms, these spills will result in only a light offing of a small stretch
                 of backbai,rrier beach. The spilled oil will be cleaned manually within a week with no effects on beach
                 morphology. The impacts to coastal barriers from spills are expected to be very low.
                     Impacts from onshore and nearshore construction of OCS-related infrastructure (pipeline landfalls,
                 navigation channels, service bases, platform yards, etc.) are not expected to occur, because no new
                 infrastructure construction is anticipated as a result of the proposed action. Although some maintenance
                 dredging is expected to occur, this activity has not been shown to have a negative impact on barriers, and the
                 need for dredging cannot be attributed to the small percentage of vessel traffic in these channels accounted
                 for by Base Case activities.

                     Conclusion


                     The proposed action is not expected to result in permanent alterations of barrier beach configurations,
                 except in localized areas downdrift from channels that have been dredged and deepened. The contribution
                 to this localized erosion is expected to be less than I percent.

                     Wetlands (Section IVD.2a(l)(b))

                     No off spills from offshore sources are expected to occur and contact coastal wetlands under the Base Case
                 scenario. Although several spills between 1 and 50 bbl are expected to contact wetlands from inshore barge
                 accidents in the WPA, the concentrations of oil that contact wetlands will have only short-term die-back effects
                 on small areas of vegetation. Complete recovery of the affected vegetation is expected within a growing season.
                 None of these spills will contact seagrass beds because of the location of beds in an area that does not include
                 OCS-related oil terminals and barge traffic.
                     No new dredging projects for pipelines or navigation channels are projected under the Base Case scenario.
                 Few to no impacts from maintenance dredging are expected, given the small contribution of OCS vessel traffic
                 under the Base Case to navigational usage of the channels.
                     Erosion of wetlands from OCS vessel wakes is not expected to result in significant erosion of wetland
                 shorelines because of the location of navigation channels in open water areas along much of the vessel route
                 to an onshore facility.

                     Conclusion


                     The proposed action is expected to result in no permanent alterations of wetland habitat, except for the
                 erosion of less than 1 ha of wetlands along navigation channel margins. These losses could be offset or even
                 exceeded by wetland gains from the beneficial disposal of dredged material generated during channel
                 maintenance and deepening operations.

                 Sensitive Offshore Resources

                     Deep-waterBenthic Communities (Section IVD.2a.(2)(a))

                     The only impact-producing factor threatening the deep-water benthic communities is physical disturbance
                 of the bottom, which would destroy the organisms comprising these communities. Such disturbance would
                 come from those OCS-related activities associated with pipelaying, anchoring, structure emplacement, and
                 seafloor blowouts. Only structure emplacement is considered to be a threat, and then only to the high-density
                 (Bush Hill-type) communities; the widely distributed low-density communities would not be at risk. The
                 provisions of NTL 88-11 (currently in effect), requiring surveys and avoidance prior to drilling, will greatly duce,
                 but not completely eliminate, the risk and potential effects.











                                                                                                                                   11-35


                    Conclusion


                    The proposed action is expected to cause little damage to the physical integrity, species diversity, or
                biological productivity of either the widespread, low-density chemosynthetic communities or the rarer, widely
                scattered, high-density Bush Hill-type chemosynthetic communities. Recovery from any damage is expected
                to take less than 2 years.

                    Topographic Features (Section IVD.2.a(2)(b))

                    Several impact-producing factors (anchoring, structure emplacement, effluent discharge, blowouts, oil spills,
                and structure removals) may threaten the communities of the topographic features.
                    Because the analysis of impacts includes the application of the proposed Topographic Features Stipulation,
                operational discharges (drilling muds and cuttings, produced waters) would have little impact on the biota of
                the banks. Recovery from any impact would be rapid.
                    Blowouts may similarly cause damage to benthic biota, but due to the application of the proposed
                Topographic Features Stipulation for this analysis, they would have little impact on the biota of the banks.
                Recovery from any impact would be rapid.
                    Oil spills (there is an estimated 6 percent chance of an oil spill greater than or equal to 1,000 bbl occurring
                in the Western Gulf as a result of this proposed action and no spill greater than 1,000 bbl is assumed) will
                cause damage to benthic organisms if the oil contacts the organisms; such contact is likely only from spills from
                blowouts, which, because of the proposed Topographic Features Stipulation, will not occur very near to the
                biota of the banks.


                    Conclusion


                    The proposed action is expected to cause little to no damage to the physical integrity, species diversity, or
                biological productivity of the habitats of the topographic features of the Gulf of Mexico. Small areas of 5-10m         2
                would be impacted, and recovery from this damage to pre-impact conditions is expected to take less than 2
                years, probably on the order of 2-4 weeks.

                Water Quality (Section IVD.2.a.(3))

                    Coastal and Estuarine Waters


                    All existing onshore infrastructure and associated coastal activities occurring in support of proposed Sale
                143 will contribute to the degradation of regional coastal and nearshore water quality to a minor extent because
                each provides a low measure of continuous contamination. No onshore OCS produced water discharges are
                assumed for the proposed sale. Wastes and contaminated equipment from offshore will be brought ashore for
                disposal and storage. Adverse impacts could occur to surface and groundwater in proximity to improperly
                designed and maintained disposal sites and facilities. OCS-related vessel traffic is likely to impact water quality
                through routine releases of bilge and ballast waters, chronic fuel and tank spills, trash, and low-level releases
                of the contaminants in antifouling paints. The improper storage and disposal of oilfield wastes and
                contaminated oilfield equipment would adversely impact surface and ground waters in proximity to disposal
                facilities, cleaning sites, and scrap yards.

                   Marine Waters


                    Based on projected sale-related support activities, offshore Subarea W-1 would receive the greatest portion
                of pipeline burial activities, whereas, offshore Subarea W-3 would receive the largest amounts of operational
                discharges. Immediate effects would be brought about by increased drilling, construction and pipelaying
                activities, causing an increase in water column turbidity (lasting for several hours with mud discharges and
                several weeks with dredging-pipelaying activities). Proposed produced water and drilling fluid discharges will











                  11-36


                  encounter rapid dispersion in marine waters and be rapidly diluted within the immediate vicinity of the
                  discharge source. Drilling fluid (mud) discharge plumes will be diluted to background leveli within a period
                  of hours and/or within several hundred meters of the discharge source.              Significant increases in water
                  concent Itions of dissolved and particulate hydrocarbons and trace metals are not expected outside the initial
                          r4
                  mixing zone or immediate vicinity of the discharge source. Higher concentrations of trace metals, salinity,
                  temperature, organic compounds, and radionuclides, and lower dissolved oxygen may be present near the
                  discharge source.
                       Program-related spills will introduce oil into coastal and offshore waters and create elevated hydrocarbon
                  levels (up to 100+,ug/1) within affected waters. Much of the oil will be dispersed throughout the water column
                  over several days to weeks. Little effect to water use is anticipated from these spills and then only in an area
                  near the source and slick.


                  Conclusion


                       An identifiable change to the ambient concentration of one or more water quality parameters will be
                  evident up to several hundred to 1,000 m from the source for periods lasting up to several weeks in duration
                  in marine and coastal waters. Chronic, low-level pollution related to the proposal will occur throughout the
                  life of the proposed action.

                  Air Quality (Section IVD.2a.(4))

                       Emissions of pollutants into the atmosphere from the activities associated with the pro-posed action are
                  likely to have a low impact on offshore air quality because of the prevailing atmospheric conditions, emission
                  heights, and pollutant concentrations. Onshore impact on air quality from emissions from the OCS Activities
                  are estimated to be low because of the atmospheric regime, the emission rates, and distance of these emissions
                  from the coastline. Section IV.D.2.a.(4) is based on average conditions; however, there will be days of low
                  mixing heights and wind speeds which could increase impact levels. These conditions are characterized by fog
                  formation which in the Gulf occurs about 35 days a year mostly during winter. Impact from. these conditions
                  is reduced in winter because the onshore winds have the smallest frequency and rain removal is greatest.

                  Conclusion


                       Emissions of pollutants into the atmosphere from activities for the Proposed Action are expected to have
                  concentrations that would not change onshore air quality classifications. Increase in onshore concentrations
                  of air pollutants are estimated to be about 1 pgm-3 (box model steady concentrations). This concentration will
                  have minimal impacts during winter because onshore winds occur only about 34 percent of the time and
                  maximum impacts in summer when onshore winds occur 85 percent of the time.

                  Mafine Mammals


                       Nonendangered and Nonthreatened Species (Section IV.D.2a.(5)(a))

                       Activities resulting from the proposed action have a potential to cause detrimental effects on
                  nonendangered marine mammals. These marine mammals could be impacted by operational discharges,
                  helicopter and vessel traffic, platform noise, explosive platform removals, seismic surveys, oilspills, and oil-spill
                  response activities. The effects of the majority of these activities are estimated to be sublethal. Potential lethal
                  effects are estimated only from oil spills greater than or equal to 1,000 bbl. Sale-related oil spills of any size
                  are estimated to seldom contact nonendangered and nonthreatened marine mammals.











                                                                                                                                 11-37


                     Conclusion
                     The impact of the Base Case scenario on nonendangered and nonthreatened marine mammals within the
                 potentially affected area is expected to result in sublethal effects that occur periodically and result in short-term
                 physiological or behavioral changes, as well as some degree of avoidance of the impacted area(s).

                     Endangered and Rreatened Species (Section IVID.2a.(5)(b))
                     Activities resulting from the proposed action have a potential to cause detrimental effects on endangered
                 marine mammals. These marine mammals could be impacted by operational discharges, helicopter and vessel
                 traffic, platform noise, explosive platform removals, seismic surveys, oil spills, and oil-spill response activities.
                 The effects of the majority of these activities are estimated to be sublethal. Potential lethal effects are
                 estimated only from oil spills greater than or equal to 1,000 bbl. Sale-related oil spills of any size are estimated
                 to seldom contact endangered and threatened marine mammals.

                     Conclusion

                     The impact of the Base Case scenario on endangered and threatened marine mammals within the
                 potentially affected area is expected to result in sublethal effects that occur periodically and result in short-term
                 physiological or behavioral changes, as well as some degree of avoidance of the impacted areas.

                 Marine Turtles (Section IVD.Za.(6))
                     Activities resulting from the proposed action have a potential to cause detrimental effects on marine turtles.
                 Marine turtles could be impacted by structure installation, pipeline placement, dredging, operational discharges,
                 OCS-related trash and debris, vessel traffic, explosive platform removals, oil-spill response activities, and oil
                 spills. The effects of the majority of these activities are estimated to be sublethal. Potential lethal effects are
                 estimated only from oil spills greater than or equal to 1,000 bbl. Sale-related oil spills of any size are estimated
                 to seldom contact marine turtles.


                 Conclusion

                     The impact of the Base Case scenario on marine turtles within the potentially affected area is expected
                 to result in sublethal effects that are chronic and could result in persistent physiological or behavioral changes.

                 Coastal and Marine Birds

                     Nonendangered and Nonthreatened Species (Section IVD.2a.(7)(a))
                     Activities resulting from the proposed action have the potential to cause detrimental effects on coastal and
                 marine birds. It is estimated that the effects from oil spills, OCS service vessel and helicopter traffic near
                 coastal areas, pipeline landfalls and coastal construction, entanglement, and ingestion of trash and debris on
                 coastal and marine birds are negligible and of nominal occurrence. As a result there will be no perceivable
                 disturbance to Gulf coastal and marine birds.


                     Conclusion

                     The impact of the Base Case scenario on nonendangered and nonthreatened coastal and marine birds
                 within the potentially affected area is expected to result in no discernible decline in a population or species and
                 no change in distribution and/or abundance on a local or regional scale. Individuals experiencing sublethal
                 effects will recover to pre-disturbance condition in less than one generation.











                  11-38


                      Endangered and 7hreatened Species (Section IVD.2a-(7)(b))

                      Endangered and -threatened birds can be impacted by oil spills, service-vessel and helicopter traffic,
                  displacement from onshore pipeline landfalls, and entanglement and ingestion of offshore oil- and gas-related
                  plastic debris. The impact of these activities are inconsequential because they are primarily nonlethal and/or
                  the probability of an interaction is unlikely.

                      Conclusion


                      The impact of the Base Case scenario on endangered and threatened birds within the potentially affected
                  area is expected to result in no discernible decline in a population or species and no change in distribution
                  and/or abundance on a local or regional scale. Individuals experiencing sublethal effects will recover to pre-
                  disturbance condition in less than one generation.

                  Commercial Fisheries (Section IVD.2a.(8))

                      Activities resulting from the proposed action have the potential to cause detrimental effects to commercial
                  fisheries. It is estimated that the effects from emplacement of production platforms, underwater OCS
                  obstructions, production platform removals, seismic surveys, oil spills, subsurface blowouts, and OCS discharge
                  of drilling muds and produced waters on commercial fisheries are negligible and of nominal occurrence. As
                  a result there will be no perceivable disturbance to Gulf commercial fisheries.

                  Conclusion


                      The impact of the Base Case scenario on commercial fisheries within the potentially affected area is
                  expected to result in no discernible decrease in a population of commercial importance, their essential habitat,
                  or in commercial fisheries on a local scale. Any affected population is expected to recover to pre-disturbance
                  condition in less than one generation.

                  Recreational Resources and Activities


                      Beach Use (Section IVD.2a.(9)(a))

                      Marine debris lost from OCS operations associated with drilling 320 new wells and producing oil and gas
                  from 10 new platform complexes throughout the WPA will occur from time to time and adversely affect the
                  aesthetics of Texas recreational beaches.


                      Conclusion


                      The proposed action is expected to result in periodic loss of solid waste items likely to wash up on
                  recreational beaches, which is expected to diminish enjoyment of some beach visits but which is unlikely to
                  affect the number or type of visits currently occurring on Texas beaches.

                      Marine Fishing (Section ITID.2a.(9)(b))

                      Platforms installed within 30 mi of shore as a result of this proposed action are likely to attract fishermen
                  and to improve fishing success for a period of about 20 years. No oil spills of 1,000 bbl or greater are assumed
                  to occur, and the few spills greater than I and less than or equal to 50 bbl that are expected will have little or
                  no impact of marine fishing.











                                                                                                                                11-39


                      Conclusion

                      One platform complex (2-3 structures) installed within 30 mi of shore as a result of this proposed sale is
                  expected to attract fishermen and to improve fishing success in the immediate vicinity of the platform complex
                  for a period of about 20 years.

                  Archaeological Resources

                      Historic (Section IVD.2.a.(10)(a))

                      The greatest potential impact to an historic archaeological resource as a result of the proposed action
                  would result from a contact between an OCS offshore activity (platform installation, drilling rig emplacement,
                  dredging, or pipeline project) and an historic shipwreck. A recently completed, MMS-funded study (Garrison
                  et al., 1989) has resulted in the refinement of the high probability areas for the location of historic period
                  shipwrecks. A new NTL for archaeological resources in the Gulf of Mexico Region (NTL 91-02) has increased
                  the survey linespacing density for historic shipwrecks from 150 in to 50 in.
                      Most other activities associated with the proposed action are expected to have very low impacts on historic
                  archaeological resources. No new onshore infrastructure construction or pipeline landfalls are expected as a
                  result of the proposed action. Historic cultural resources, therefore, will not be affected by these activities.
                  The chance of contact from an oil spill associated with the proposed action is very low. Furthermore, the
                  impact from an off-spill contact on an historic coastal site, such as a fort or lighthouse, would be visual due to
                  oil contamination. These impacts would be temporary and reversible. Impacts from dredging are expected
                  to be minimal.
                      An OCS activity could contact a shipwreck because of incomplete knowledge on the location of shipwrecks
                  in the Gulf. Although this occurrence is not probable, such an event would result in the disturbance or
                  destruction of important historic archaeological information. Other factors associated with the proposed action
                  are not expected to affect historic archaeological resources.

                      Conclusion

                      There is a very small possibility of an impact between OCS oil and gas activities and a historic shipwreck
                  or site. Should such an impact occur, unique or significant historic archaeological information could be lost.

                      Prehistoric (Section IVD.2.a.(10)(b))

                      Several impact-producing factors may threaten the prehistoric archaeological resources of the Western
                  Gulf. An impact could result from a contact between an OCS activity (pipeline and platform installations,
                  drilling rig emplacement and operation, dredging, and anchoring activities) and a prehistoric site located on
                  the continental shelf. The archaeological surveys and archaeological clearance of sites that are required prior
                  to an operator beginning oil and gas activities in a lease block are estimated to be 90 percent effective at
                  identifying possible prehistoric sites. The survey and clearance provide a significant reduction in the potential
                  for a damaging interaction between an impact-producing factor and a prehistoric site. There is a very small
                  possibility of an OCS activity contacting a prehistoric site. Should such an impact occur, there could be damage
                  to or loss of significant or unique archaeological information.
                      Onshore development as a result of the proposed action could result in the direct physical contact from
                  new facility construction, pipeline trenching, and navigation canal dredging. None of these activities is expected
                  to occur under the Base Case. The impact level from these factors is considered to be very low.
                      Should an off spill contact a coastal prehistoric site, the potential for dating the site using radiocarbon
                  methods could be destroyed. Oil-spill cleanup operations could physically impact coastal prehistoric sites.
                  Previously unrecorded sites could also experience an impact from oil-spill cleanup operations on beaches. The
                  probability of a large spill occurring and contacting a coastal prehistoric site within 10 days is very low (2%),
                  and it is assumed that no contact will occur. A few spills greater than 1 and less than or equal to 50 bbl are










                  11-40


                  assumed to contact the coast, but- these small spills would probably not cover an exposed sjite, such as a shell
                  midden, with enough oil to contaminate all the datable organic remains. The impact level from oil-spill contact
                  is expected to be very low.

                       Conclusion


                       There is a very small possibility of an OCS activity contacting a prehistoric site. Should such an impact
                  occur, there could be damage to or loss of significant or unique archaeological information..

                  Socioeconomic Conditions


                       Population, Labor, and Employment (Section IVD.2a.(11)(a))

                       Peak annual changes in the population, labor, and employment of all coastal subareas jin the Central and
                  Western Gulf resulting from the proposed action in the Western Gulf represent less than 1 percent of the levels
                  expected in the absence of the proposed action. The coastal communities of the CPA are expected to support
                  over 72 percent of the total employment generated by the Western Gulf sale. The WPA contributes the
                  remaining 28 percent of total employment impacts. Employment resulting from oil-spill clean-up activities due
                  to the proposed action is negligible. It is expected that employment demands in support of the proposed action
                  will be met with the existing population and available labor force in the region.

                       Conclusion


                       The Base Case impact of the proposed action in the Western Gulf on the population, labor, and
                  employment of the counties and parishes of the Central and Western Gulf socioeconomic impact area is
                  expected to be less than I percent of the levels expected in the absence of the proposal.

                       Public Smices and Infirastructure (Section IVD. 2 a. (11) (b))

                       Impacts to public services and infrastructure would be related to dramatic increases or decreases in
                  population. Specific impact-producing factors examined in this analysis include fluctuations in work force,
                  migration into or out of the coastal subareas, and the relatively high Wages made by personnel involved in the
                  oil and gas industry. An analysis of historical trends indicates that population impacts of greater than I percent
                  involve positive net migration into a given area. Under the Base Case, population impacts are not expected
                  to exceed the peak year impact of 0.17 percent. No positive net migration into the coastal subareas of the
                  Central and Western Gulf of Mexico is expected to occur as a result of the proposed action. It is expected that
                  employment will occur from those currently employed in the oil and gas industry, as well as unemployed,
                  underemployed, and new employees already living in the area. In addition, jobs created by the proposal would
                  likely reduce the amount of migration out of the coastal subareas when compared to scenarios without the
                  proposal. It is expected that employees leaving public service and infrastructure related jobs could be replaced
                  from the existing labor pool.

                       Conclusion


                       Population and employment impacts that result from the proposed action under the Base Case scenario
                  will not result in disruptions to community infrastructure beyond what is anticipated by in-place planning and
                  development agencies.

                       Social Pattems (Section IVD.2a. (11)(c))

                       Impacts to social patterns would be related to dramatic changes in population and the disruption of
                  environmental resources, as well as conditions inherent to OCS-related employment (i.e., work scheduling and











                                                                                                                                   11-41


                 rate of pay). Specific impact-producing factors examined in this analysis include fluctuations in the workforce,
                 migration into or out of the coastal subareas, work scheduling, displacement from traditional occupations, and
                 relative income. An analysis of historical trends indicates that population impacts of greater than 1 percent
                 typically involve positive net migration into a given area. Under the Base Case, population impacts are not
                 expected to exceed the peak year impact of 0.17 percent. No positive net migration into coastal subareas of
                 the Central and Western Gulf of Mexico is expected to occur as a result of the proposal. It is expected that
                 employment will occur from those currently employed in the oil and gas industry, as well as unemployed,
                 underemployed, and new employees already living in the area. It is expected that jobs created by the proposal
                 would likely reduce the amount of out-migration when compared to scenarios without the proposal. It is
                 expected that minor displacement from traditional occupations will occur as a result of the proposed action.
                 This displacement will be mitigated, to some extent, by the extended work schedule associated with OCS-
                 related employment The extended work schedule is expected to have some deleterious effects on family life
                 in pertinent, individual cases. Impacts caused by the displacement of traditional occupations and relative wages
                 are expected to occur to a minimal extent.

                     Conclusion

                     No net migration is expected to occur as a result of the proposed action. Impacts on social patterns are
                 expected to occur in some individual cases as a result of extended work schedules, displacement from
                 traditional occupations, and relative wages.

                 c. Mitigating Measures

                     Measures have been developed to mitigate possible impacts of OCS activities on environmental resources
                 and non-OCS activities. The four stipulations presented below have been applied to appropriate OCS leases
                 for many years. These stipulations, while proven effective, are considered as potential mitigating measures in
                 this EIS. The Secretary will make a decision prior to Sale 143 on whether or not to apply these measures to
                 appropriate leases resulting from the sale. The analyses in this EIS of the impacts to the resources to which
                 these stipulations apply assume that the measures will be in place. However, the analyses also contain a
                 description of possible impacts without the protection afforded by the stipulations.

                 (1) Topographic Features Stipulation

                     The topographic features of the Western Gulf provide habitat for coral and coral community organisms
                 (Section III.B.2.). As discussed in Section IV.13.2.a.(2)(b) of the Final EIS for Sales 131,135, and 137 (USDOI,
                 MMS, 1990a), these communities would be severely and adversely impacted (i.e., have an expected impact level
                 of very high) by oil and gas activities resulting from the proposed action if such activities took place on or near
                 these communities without the Topographic Features Stipulation and were not mitigated. The USDOI has
                 recognized this problem for some years, and since 1974 stipulations have been made a part of leases on blocks
                 on or near these biotic communities so that impacts from nearby oil and gas activities were mitigated to the
                 greatest extent possible. This stipulation would not prevent the recovery of oil and gas resources, but it would
                 serve to protect valuable and sensitive biological resources.
                     The Topographic Features Stipulation was formulated based on consultation with various Federal agencies
                 and comments solicited from State, industry, environmental organizations, and academic representatives. The
                 stipulation wording is based on the scientific information collected since the inception of the stipulation. This
                 information includes various Bureau of Land Management/MMS-funded studies on the topographic highs in
                 the Western Gulf, numerous stipulation-imposed, industry-funded monitoring reports, and the National
                 Research Council (NRC) report entitled Drilling Discharges in the Marine Environment (1983).










                  1142


                      The rationale for the requirements in the stipulation is based on the following facts:

                           (a)   Shunting of the drilling effluent to the nepheloid layer confines the effluent to a level
                                 deeper than that of the living reef of a high-relief topographic feature. Shunting is
                                 therefore an effective measure for protecting the biota of high relief topographic
                                 features (Bright and Rezak, 1978; Rezak and Bright, 1981; NRC, 1983).

                          (b)    Biological effects on the benthos from the deposition of nonshunted discharge are
                                 mostly limited to within 1,000 m of the discharge (NRC, 1983).

                          (c)    The biota of topographic features can be categorized into depth-related zones defined
                                 by degree of reef-building activity (Rezak and Bright, 1981; Rezak et al., 1983 and
                                 1985).

                      The stipulation establishes No Activity Zones at the topographic features. The zone is defined by the 85-m
                  isobath because, generally, the biota shallower than 85 m are more typical of the Caribbean reef biota, while
                  the biota deeper than 85 m are similar to soft-bottom organisms found throughout the Gulf. Where a bank
                  is in water depths less than 85 m, the deepest closing isobath defines the No Activity Zone for that bank.
                  Within the No Activity Zone, no operations, anchoring, or structures are allowed. Outside of the No Activity
                  Zones, additional restrictive zones are established within which oil and gas operations could occur, but within
                  which drilling discharges would be shunted.
                      The stipulation requires that all effluents within 1,000 m of the south Texas banks, which contain the
                  antipatharian-transitional zone, be shunted to within 10 m of the seafloor. The shelf edge banks, which contain
                  the more sensitive and productive algal-sponge zone, requires a shunt zone extending 1 nmi and a 3-nmi shunt
                  zone for development only.
                      Exceptions to this general stipulation scheme are made at two classes of banks: the Flower Gardens and
                  the low relief banks. The Flower Gardens, because they contain the northernmost example in the Gulf of living
                  coral reefs and are being considered for National Marine Sanctuary status (Section I.B.41.), are protected to
                  a greater degree than the other banks. The added provisions of the stipulation at the Flower Gardens require
                  that: (a) the No Activity Zone be based on the 100-m isobath instead of the 85-m isobath and would be
                  defined by the "1/4 1/4 1/4" system (a method of defining a specific portion of a block) rather than the actual
                  isobath; and (b) there be a 4-Mile Zone instead of a 1-Mile Zone in which shunting is required. The second
                  exception is for the low relief banks, where shunting is considered counterproductive because it would put the
                  potentially toxic drilling muds in the same water zone as the bank biota that are being protected. Because of
                  their low relief, these banks are adapted to high turbidity. Therefore, these banks contain only a No Activity
                  Zone. Claypile Bank is a low relief bank that contains the Millepora-sponge community. Because of its higher
                  priority it is given the added protection of a 1,000-Meter Zone in which monitoring is required. Since shunting
                  would be counterproductive, monitoring was chosen as a means of assuring that effluent discharge within 1,000
                  m of this high priority, low relief bank would not affect the biota of Claypile Bank.












                                                                                                                       11-43


                 The banks causing this stipulation to be applied to blocks of the Western Gulf are as follows:

                          Bank Name               Isobath (meters)            Bank Name            Isobath (metgos
                                        Shelf Edge Banks                                  Low Relief BankS2

                          West Flower Garden Bank'           100              Mysterious Bank           74, 76, 78, 80, 84
                          (defined by 1/4 1/4 1/4 system)                     (see leasing map)
                          East Flower Garden Bank'           100              Blackfish Ridge           70
                          (defined by 1/4 1/4 1/4 system)
                          MacNeil Bank                       82               Big Dunn Bar              65
                          29 Fathom Bank                     64               Small Dunn Bar            65
                          Rankin Bank                        85               32 Fathom Bank            52
                          Geyer Bank                                          85 Coffee Lump            Various
                          Elvers Bank                                         85 (see leasing map)
                          Bright Bank   5                    85               Claypile Bank3            50
                          McGrail Bank5                      85
                          Rezak Bank    5                    85
                          Sidner Bank5                       85                           South Texas BankS4
                          Parker Bank5                       85
                          Stetson Bank                       62               Dream Bank                78,82
                          Applebaum Bank                     85               Southern Bank             80
                                                                              Hospital Bank             70
                                                                              North Hospital Bank       68
                                                                              Aransas Bank              70
                                                                              South Baker Bank          70
                                                                              Baker Bank                70

                          'Flower Garden Banks - In paragraph (c), a 4-Mile Zone rather than a 1- Mile Zone
                          applies.
                          2Low Relief Banks - Only paragraph (a) applies.
                          3CIaypile Bank - Paragraphs (a) and (b) apply. In paragraph (b) monitoring of the
                          effluent to determine the affect on the biota of Claypile Bank shall be required
                          rather than shunting.
                          4SOUth Texas Banks - Only paragraphs (a) and (b) apply.
                          5Central Gulf of Mexico banks with a portion of their 1-Mile Zone and/or 3-Mile
                          Zone in the Western Gulf of Mexico.


                  The stipulation reads as follows:

                                                    Topographic Features Stipulation
                                                        (Western Planning Area)

                       (a)   No activity including structures, drilling rigs, pipelines, or anchoring will be allowed
                             within the listed isobath ("No Activity Zone") of the banks as listed above.

                       (b)   Operations within the area shown as "1,000 Meter Zone" shall be restricted by shunting
                             all drill cuttings and drilling fluids to the bottom through a downpipe that terminates
                             an appropriate distance, but no more than ten meters, from the bottom.











                 11-44


                          (c)   Operations within the area shown as I Mile Zone" shall be restricted by shunting all
                                drill cuttings and drilling fluids to the bottom through a downpipe that termbaates an
                                appropriate distance, but no more than ten meters, from the bottom. (Where there is
                                a I Mile Zone" designated, the 1,000 Meter Zone in paragraph (b) is not designated.)

                         (d)    Operations within the area shown as "3 Mile Zone" shall be restricted by shunting all
                                drill cuttings and drilling fluids from development operations to the bottom through a
                                downpipe that terminates an appropriate distance, but no more than ten meters, from
                                the bottom.


                 Effectiveness of the Lease Stipulation

                     The purpose of the stipulation is to protect the biota of the topographic features from adverse effects due
                 to routine off and gas activities. Such effects include physical damage from anchoring and rig emplacement
                 and potential toxic and smothering effects from muds and cuttings discharges. The Topographic Features
                 Stipulation has been used on leases since 1974 and this experience shows conclusively that the stipulation
                 effectively prevents damage to the biota of these banks from routine off and gas activities. Anchoring on the
                 sensitive portions of the features by the oil and gas industry has been prevented. Monitoring studies conducted
                 as required by the stipulation have demonstrated that the shunting requirements are effective in preventing the
                 muds and cuttings from impacting the biota of the banks. The stipulation, if adopted for the proposed action,
                 will continue to protect the biota of the banks, specifically as discussed below.
                     The analyses of the proposed actions in the Final EIS for Sales 131, 135, and 137 (USDOI, MMS, 1990a)
                 were done without the stipulations in place. A thorough analysis of the impacts of oil and gas activities as they
                 relate to topographic features is presented there. The following is a summary of that analysis, which is hereby
                 incorporated by reference.
                     Several impact-producing factors may threaten the communities of the topographic features. Anchoring
                 of vessels and structure emplacement result in physical disturbance of the benthic environment and are the
                 most likely activities to cause permanent or long-lasting impacts to sensitive offshore habitats. Recovery from
                 damage caused by such activities may take 10 or more years. Operational discharges (drilling muds and
                 cuttings, produced waters) may impact t  'he biota of the banks due to turbidity and sedimentation, resulting in
                 death to benthic organisms in large areas. Recovery from such damage may take 10 or more years. Blowouts
                 may similarly cause damage to benthic biota by resuspending sediments, causing turbidity and sedimentation,
                 and resulting in death to benthic organisms. Recovery from such damage may take up to 10 years.
                 Fortunately, blowouts seldom occur in the Gulf. Oil spills will cause damage to benthic organisms if the oil
                 contacts the organisms; such contact is likely only from spills from blowouts. Structure removal using
                 explosives (as is generally the case) results in water turbidity, sediment deposition, and potential explosive
                 shock-wave impacts. Such effects include physical damage from anchoring and rig emplacement and potential
                 toxic and smothering effects from muds and cuttings discharges. Severe damage to benthic organisms could
                 result. Recovery from such damage could take more than 10 years. The above activities resulting from this
                 proposal, especially bottom-disturbing activities, have a potential for causing very high impacts to the biota of
                 the topographic features. While some of the activities are expected to result in lower impacts, those having
                 the greatest impacts are also those most likely to occur. The proposed action, without benefit of the
                 Topographic Features Stipulation or comparable mitigation, is expected to have a very high impact on the
                 sensitive offshore habitats of the topographic features.
                     Mechanical damage resulting from off and gas operations is probably the single mostsevere impact to
                 benthic areas. The No Activity Zone designation would completely eliminate this threat from leasing activities.
                 The sensitive biota within the zones provided for in the Topographic Features Stipulation will thus be
                 protected.
                     The stipulation protects the low relief banks, except Claypile Bank, with only a No Activity Zone. The
                 biota of these banks and the turbidity of the water are such that protective measures for the drilling discharges
                 are not warranted. However, mechanical damage to the banks from drilling and anchoring could significantly
                 impact these resources. The No Activity Zone protects the banks from these impacts. The stipulation provides
                 an added measure of protection for Claypile Bank, a low relief bank. The stipulation requires a No Activity
                 Zone and a 1,000-Meter Zone in which monitoring will be required. Claypile Bank is the onl1y low-relief bank











                                                                                                                                   11-45


                 that is known to be inhabited by the Millepora-sponge community. This assemblage is categorized by Rezak
                 and Bright (1981) as a Category B community, a zone of minor reef-building activity worthy of increased
                 protection. Due to the low relief of the bank (only 5 m), shunting would be counterproductive. Therefore,
                 a 1,000-Meter Zone in which monitoring is required will be imposed. Any impacts from drilling will thereby
                 be documented so that further protective measures could be taken.
                     The categories of Rezak and Bright (1981) and their definitions are as follows:

                          Category A.     zone of major reef-building activity; maximum environmental protection
                                          recommended;

                          Category B:     zone of minor reef-building activity-, environmental protection recommended;

                          Category Q      zone of negligible reef-building activity, but crustose algae present;
                                          environmental protection recommended; and

                          Category D:     zone of no reef-building or crustose algae; additional protection not necessary.

                     The stipulation requires that all effluents within 1,000 m of a high-relief topographic feature categorized
                 by Rezak and Bright (1981) as a Category C bank be shunted. The banks will be protected from impact from
                 drilling discharges within the 1,000-m zone because the potentially harmful materials in drilling muds are
                 trapped in the bottom boundary layer and do not move upon the bank where the biota of concern are located.
                 Surface drilling discharge at distances greater than 1,000 m from the bank is not expected to adversely impact
                 the biota since effects are limited to 1,000 m.
                     The stipulation will protect the remaining Category A and B banks with greater restrictions. (Applebaum
                 Bank is categorized as Category C; however, it contains the algal-sponge community, which is indicative of
                 Category A banks, and is, therefore, stipulated as a Category A bank.) Surface discharge will not be allowed
                 within 1 nmi of these more sensitive banks. Thus, the stipulation prevents impacts to the biota of these
                 sensitive banks from drilling discharges within 1 nmi. Surface discharges outside of 1 nmi are not expected to
                 adversely impact the biota of the banks, as adverse effects from surface discharges are limited to 1,000 m.
                 However, it is possible that because multiple wells from a single platform (surface location) are typically drilled
                 during development operations extremely small amounts of muds discharged more than 1 nmi from the bank
                 may reach the bank. In order to eliminate the possible cumulative effect of muds discharged from numerous
                 wells outside of 1 nmi, the stipulation imposes a 3-Mile Zone in which shunting of development effluent would
                 be required. The stipulation will require increased protection to the Flower Gardens out to four miles.
                 Shunting would be required within a 4-Mile Zone. This is a measure proven effective near topographic
                 features.
                     The stipulation would prevent damage to the biota of the banks from routine oil and gas activities resulting
                 from the proposal. Furthermore, oil and gas resources present near such areas could be recovered. However,
                 the stipulation will not protect the banks from the adverse effects of an accident such as a large blowout on
                 a nearby oil or gas operation.

                 (2) Arcltaeolo&al Resource Stipulation

                     The Archaeological Resource Stipulation has been placed on leases issued in the Gulf of Mexico Region
                 since 1974. The stipulation provides protection for prehistoric and historic archaeological resources by
                 requiring remote sensing surveys in areas designated to have a high probability for archaeological resources
                 and by requiring protection of archaeological resources discovered outside of the designated high probability
                 zones. The stipulation is included in the analysis of this proposed action.

                          (a)    "Archaeological resource" means any prehistoric or historic district, site, building,
                                 structure, or object (including shipwrecks); such term includes artifacts, records, and
                                 remains which are related to such a district, site, building, structure, or object (16 U.S.C.
                                 470w(5)). "Operations" means any drilling, mining, or construction or placement of any
                                 structure for exploration, development, or production of the lease.











                 11-46


                          (b)    If the Regional Director (RD) believes an archaeological resource may exist in the lease
                                 area, the RD will notify the lessee in writing. The lessee shall then comply with
                                 subparagraphs (1) through (3).

                                 (1)   Prior to commencing any operations, the lessee shall prepare a report, as
                                       specified by the RD, to determine the potential existence of any archaeological
                                       resource that may be affected by operations. The report, prepared by an
                                       archaeologist and geophysicist, shall be based on an assessment of data from
                                       remote- sensing surveys and of other pertinent archaeological and environmental
                                       information. The lessee shall submit this report to the RD for review.

                                 (2)   If the evidence suggests that an archaeological resource may be present, the
                                       lessee shall either:


                                       (i)   Izcate the site of any operation so as not to adversely affect the area
                                             where the archaeological resource may be; or

                                       (ii)  Establish to the satisfaction of the RD that an archaeological resource does
                                             not exist or will not be adversely affected by operations. This shall be done
                                             by further archaeological investigation, conducted by an archaeologist and
                                             a geophysicist, using survey equipment and techniques deemed necessary
                                             by the RD. A report on the investigation shall be submitted to the RD for
                                             review.


                                 (3)   If the RD determines that an archaeological resource is likely to be present in the
                                       lease area and may be adversely affected by operations, he win notify the lessee
                                       immediately. The lessee shall take no action that may adversely affect the
                                       archaeological resource until the RD has told the lessee how to protect it.

                         (c)     If the lessee discovers any archaeological resource while conducting operations on the
                                 lease area, the lessee shall report the discovery immediately to the RD. The lessee
                                 shall make every reasonable effort to preserve the archaeological resource until the RD
                                 has told the lessee how to protect it.

                Effectiveness of the Lease Stipulation

                     Prehistoric archaeological resources would be slightly affected (i.e., have an expected impact level of very
                low) by oil and gas activities resulting from the proposed action if such activities took place within the zone
                of high probability for prehistoric resources. Historic archaeological resources would be adversely affected (i.e.,
                have an expected impact level of moderate) by oil and gas industry activities resulting from the proposed action
                if such activities took place within the zone of high probability for historic resources. The DOI has recognized
                its legal responsibilities for protection of archaeological resources on the Gulf of Mexico OCS, and since 1974
                stipulations have been made a part of leases on blocks within the Gulf of Mexico Region. The stipulation does
                not prevent the recovery of oil and gas resources, but it does provide a mechanism to protect our Nation's
                prehistoric and historic OCS archaeological resources.
                     The Archaeological Resource Stipulation should assure MMS compliance with Federal laws and regulations
                requiring protection of archaeological resources. The National Historic Preservation Act of 1966, as amended,
                requires each Federal agency to establish a program to locate, inventory, and nominate to -the Secretary all
                properties under the agency's ownership or control that appear to qualify for inclusion on the National
                Register. Section 2(a) of Executive Order 11593 provides that Federal agencies shall locate, inventory, and
                nominate to the Secretary of the Interior all sites, buildings, districts, and objects under their jurisdiction or
                control that appear to qualify for listing on the National Register of Historic Places. Section 11(g)(3) of the
                OCSLA, as amended, states that "such exploration (oil and gas) win not. . . disturb any site, structure, or object
                of historical or archaeological significance." Because of these laws and regulations, the withdrawal of the











                                                                                                                                  11-47


                Archaeological Resource Stipulation would not relieve the MMS of its legal responsibility to protect OCS
                archaeological resources.
                     The analyses of the proposed actions in the Final EIS for Sales 131, 135, and 137 (USDOI, MMS, 1990a)
                were presented without the stipulations in place. A thorough analysis of the impacts of oil and gas activities
                as they relate to archaeological resources is presented there. The following is a summary of that analysis, which
                is incorporated by reference.
                     The purpose of the stipulation is to provide a mechanism to protect OCS archaeological resources from
                adverse effects due to oil and gas exploration and development. Several impact-producing factors may threaten
                prehistoric and/or historic archaeological resources. The placement of drilling rigs, production platforms,
                pipelines, and anchoring could destroy artifacts or disrupt the provenience and stratigraphic context of artifacts,
                sediments, and paleoindicators from which the scientific value of the archaeological resource is derived. Oil
                spills could destroy the ability to date prehistoric sites by radiocarbon dating techniques. Dredging new
                channels and maintaining current channels could impact a historic shipwreck. Ferromagnetic debris associated
                with OCS oil and gas activities would tend to mask magnetic signatures of significant historic archaeological
                resources.
                     The stipulation is the agency's effort to comply with existing Federal laws and regulations. It provides a
                mechanism for the protection of the Nation's OCS archaeological resources. Remote-sensing surveys mandated
                in the stipulation will serve to protect archaeological resources from oil and gas activities resulting from the
                proposed action. Without the stipulation in place, the agency would still be responsible for protecting the
                Nation's OCS archaeological resources. Remote-sensing surveys would still be required to ensure compliance
                with existing laws and regulations.

                (3) Military Areas Stipukd'ion

                     The proposed Military Areas Stipulation for the Western Gulf is identical to the proposed Military Areas
                Stipulation for the Central Gulf (Section II.A-l.c.(4)) and could apply to all blocks leased within a warning area.
                The stipulation has been applied to blocks in warning areas in past lease sales in the Western Gulf and may
                be included, at the Secretary's option, in all leases resulting from this proposed action. It is considered by DOI
                and DOD to be an effective method of mitigating potential multiple-use conflicts. The military stipulation
                would place requirements for liability, electromagnetic emissions, and operational controls on the lessees.

                Effectiveness of the Lease Stipulation

                     The hold harmless section of the proposed Military Areas Stipulation serves to protect the U.S.
                Government from liability in the event of an accident involving the lessee and military activities. The actual
                operations of the military and the lessee and its agents would not be affected.
                     The electromagnetic emissions section of the stipulation requires the lessee and its agents to reduce and
                curtail the use of radio, CB, or other equipment emitting electromagnetic energy within some areas. This
                serves to reduce the impact of oil and gas activity on the communications of military missions and reduces the
                possible effects of electromagnetic energy transmissions on missile testing, tracking, and detonation.
                     The operational section requires notification to the military of oil and gas activity to take place within a
                military use area. This allows the base commander to plan military missions and maneuvers that may avoid
                the areas where oil and gas activities are taking place or to schedule around these activities. Prior notification
                helps reduce the potential impacts associated with vessels and helicopters traveling unannounced through areas
                where military activities are underway.
                     The proposed Military Areas Stipulation reduces potential impacts, particularly in regards to safety, but
                does not reduce or eliminate the actual physical presence of oil and gas operations in areas where military
                operations are conducted. The reduction in potential impacts resulting from this stipulation makes multiple-use
                conflicts most unlikely. Without the stipulation, some potential conflict is likely. The best indicator of the
                overall effectiveness of the stipulation may be that there has never been an accident involving a conflict
                between military operations and oil and gas activities.











                11-48


                (4) Notices to Lessees and Letters to Lessees

                    Notices to Lessees and Operators (NTIA) are formal documents that provide clarification, description, or
                interpretation of a regulation or OCS standard; provide guidelines on the implementation of a special lease
                stipulation.or regional requirement; provide a better understanding of the scope and meaning of a regulation
                by explaining MMS interpretation of a requirement; or transmit administrative information such as current
                telephone listings and a change in MMS personnel or office address. A detailed listing of current and effective
                Gulf of Mexico NTL's was published in the Federal Register on May 16, 1991 (56 FR 22735-22737). The MMS
                publishes an updated NTL listing annually in the Federal Register.
                    The MMS also conveys important information by way of LT1:s and ITL:s. These documents further clarify
                or supplement operational guidelines. Separate Regional mailings and the EIS process have served as the
                vehicles for communicating previously issued NTL:s, LTIA, and ITUs.
                2. Alternative B - The Proposed Action Excluding the Blocks Near
                    Biologically Sensitive Topographic Features

                    This alternative, offered for the Secretary's consideration, would protect valuable offshore biological
                resources. It affects the biologically sensitive banks (topographic features) of the Western Gulf.
                    All of the blocks included in the deletion alternative are also the blocks that are covered by the proposed
                Topographic Features Stipulation (discussed in Section 11.13.1.c.(l)), which may be included as a part of the
                proposed action by the Secretary to protect the biological habitats of these areas. The Secretary could choose
                to adopt only a part of this alternative in order to promote the environmental protection policies of the
                Departmew.

                a. Description

                   This alternative would offer for lease all the blocks offered by the proposed action, except for the 87
                unleased blocks (Figures 11-3 and 11-4) of the total 200 blocks (these blocks are listed in Appendix A) affected
                by the proposed Topographic Features Stipulation. These blocks are on or near biologically sensitive areas
                of the topographic features of the WPA. These blocks represent about 1.8 percent of the 4,715 blocks to be
                offered in the Western Gulf. This alternative would also exclude the two biologically sensitive blocks (High
                Island Area, East Addition, South Extension Block A-375 at the East Flower Garden Bank and High Island
                Area, East Addition, South Extension Block A-398 at the West Flower Garden Bank). It is estimated that the
                proposal could result in the discovery and production of 0.05 BBO and 0.74 tcf of gas during The time period
                1993-2027. For more information describing the proposed action and alternatives, see Section I.
                   The analyses of impacts summarized in this section and presented in detail in Section IV.D.2.b. are based
                on a development scenario (Base Case) formulated to provide a set of assumptions and estimates on the
                amounts, locations, and timing for OCS exploration, development, and production operations and facilities, both
                offshore and onshore. These are estimates only and not predictions of what will happen as a result of holding
                the proposed sale. A detailed discussion, with tables, of the development scenario and majorrelated impact-
                producing factors is included in Section IV.A. The following are the major estimates of activities and associated
                impact-producing factors assumed for proposed Sale 143 (Base Case). These estimates and factors were
                utilized in the impact analyses:

                        (1)    During the exploration phase, 1994-2004, there will be 210 wells drilled, resulting; in the
                               following:

                               -     the generation of 1.50 MMbbl of drilling mud and 0.39 MMbbl of drill cutting
                                     wastes, about 18 percent of which will be disposed of onshore;

                               -     offshore air emissions from well drilling operations of 204 tons of total suspended
                                     particulate matter, 59 tons of total hydrocarbons, 237 tons of sulphur oxides, 542
                                     tons of carbon monoxide, and 2,031 tons of nitric oxides;










                                                                                                                                                                 .1      1 - I -       7"            A@@ A-611 -A                        I -- I -          A-5* A-40 A@ A-o? A-441 A-411 -
                                                                                     14,                                                                         "1      - I           A-5*                1 11                                                                1        E- -711 A-'.
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                                                               m                                                                                         A-                                                                                                                             A-87         A-8
                                                               816                                                                                                                                                          A-15
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                                                                                                     MUS UN@        is"                                                  --.641MUSkA114 ISUND IA-1-1                                          A-1 17
                                                                                                                                                                               1 EA4T A4DIT14                                      A-3                     9 A-1 18
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                                                                                             1140                   oo-    A-*    - -1            A-             A- A-$        I- -I                HOSPITAL                                    A-137                                                Le
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                                                                                                                                                                                               A-41       OA-40


                                                                                                                                                                                                                                                                                        miss
                                                                                                                                                                                                                                                     TEXAS          LOUISLAKA
                                                                                                                           A%                                    -.7

                                                                                                                                                                               BLkCKFISH RIDGE


                                                                                                                                                                         A-71
                                                                                                                                                                         --.v.
                                                loot                                                                              A-
                                                         NC                                                               ITOM 9 P HE             ISLA
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                                                                                     2                                 -t                                                      Lj                                                  I

                                  Figure H-3. Location and Lease Status of Blocks Affected by Alternative B (South Texas).














                                                                              miss
                                               TEXAS         LOUISIANA                                           FLORIDA                                                                         A-486 A-487    A-488
                                                                                                                                                                                                                                                A-340
                                                                                                                                                     Aw No Activity Zone                         A-503 @@A\2    A-501

                                                                                                                                                            Leased Block                                                                                  -3
                                                                                                                                                                                                 A-512

                                                                                                                                                            Unleased Block                                                                      A-360 A-361
                                                                                                                                                                                                 A-529  -5 8 A-527

                                                                                                                                                                                                                                                COFFEE LUMP
                                                                                                                                                                                                       STETSON




                                        A-4"             A-446
                                        A-46             A-465                                                                                                                                                            A-3171   A-354             -352    A-351
                                             CLAYPILE                                                                                                                                            A-361    A- 6    A-363   A-364,   A-363                67, A-368
                                                                                             I            L   I   I   I

                                                                                                                                                                                         A-3     1, A-    A- 9            A-                           74 A-373
                                                                                                                                                                                A-573     A-38Z  A-393                    A-396 A-387                   89 A-1390
                                                                                                                                  E     ADQ1W4 SOUT E)TENWJ\                    A-596    'A-400, A-                       A-396    A-395   'A-  94          6       97
                                                   -535                                                                                                                                17S       A-401                    A-40     A-403 1        is       14
                                                                                                4 NA      RFA
                                          32 FATHOM                                         S DUT I A 0ITfpN
                                                                                                                                                                                         17      177                      ISO
                                                                                                                                                                                                                           X


                                                                                                                                                                                                         VEST AND EAST FLOWER GARDENS



                                                                                                                                                            GA 1)    8
                                                                                               E ST BR KS
                                                                                                                                                                                                     A-580,










                                                                                                                                                                                                          APPELBAUM
                                                                              MISS
                                 f            @AS            L-@ISIANAFIORIDA

                                                 A-44-7



                                                A-4 4,



























                            Figure H-4. Location and Lease Status of Blocks Affected by Alternative B (North Texas).











                                                                                                                        11-51


                                    4,050 service vessel trips and 14,200 helicopter landings;

                                    disturbance from rig emplacements of 83 ha of ocean bottom; and

                                    the likelihood of 1 blowout (Section IV.A-2.d.(8)).

                      (2)     During the development phase, 1995-2016, there will be 50 oil wells and 60 gas wells
                              drilled, resulting in the following:

                              -     the generation of 0.74 MMbbl of drilling mud and 0.157 MMbbl of drilling cutting
                                    wastes, a small amount of which will be disposed of onshore;

                              -     offshore air emissions from well drilling operations of 94 tons of total suspended
                                    particulate matter, 27 tons of total hydrocarbons, 109 tons of sulphur oxides, 248
                                    tons of carbon monoxide, and 9,31 tons of nitric oxides;

                              -     2,120 service vessel trips and 7,425 helicopter landings;

                              -     the disturbance from fixed structure emplacements of 10 ha of ocean bottom; and


                      (3)     During the production phase, 1995-2026, 0.05 BBO of oil and 0.74 tcf of gas will be
                              produced from 8 platform complexes and two floating production systems, resulting in
                              the following:

                                    the open-water discharge of 126 MMbbI of produced water;

                                    24,000 bbI of produced sands disposed of onshore;

                                    offshore air emissions from platforms of 42 tons of total suspended
                                    particulate matter, 6,500 tons of total hydrocarbons, 30 tons of sulphur
                                    oxides, 2,234 tons of carbon monoxide, and 17,150 tons of nitric oxides;

                                    2,086 service vessel trips and 109,000 helicopter landings;

                                    the removal of 15 ha of commercial fishing area (peak year estimate); and

                                    the likelihood of I blowout (Section IV.A-2.d.(8)).

                       (4)    During platform removal operations, which will occur the year after production
                              ceases, 3 platforms will be removed using explosives.

                       (5)    The transportation of gas and oil will require the following:

                              -     the construction of 80 km of gathering pipelines that will connect with existing
                                    trunklines prior to landfall, resulting in the disturbance of 26 ha of bottom and
                                    the displacement of 40,000 m3 of sediment;

                              -     9 barge trips carrying oil to 3 existing shore terminals along the Texas and
                                    Louisiana coasts; and

                              -     66 shuttle tanker trips carrying oil to four Texas and two Louisiana terminals.











                   11-52


                            (6)    Support activity will result in the following:

                                   -    No new major onshore support or processing facility construction is expected;
                                        existing OCS-related facilities will be used, with sale-related activities utilizing
                                        about 3 percent, on the average, of the capacities of the onshore infrastructure.

                                   -    the use of 15 navigation channels (less than I percent), that will be maintenance
                                        dredged periodically and one deepened to support vessel traffic;

                                   -    26 million liters of bilge water discharged in coastal waters from service vessel
                                        traffic to 27 existing bases;

                                   -    73,000 helicopter coastal crossings to reach 20 helicopter hubs; and

                                   -    air emissions from service vesseLs and helicopters of 211 tons of total suspended
                                        particulate matter, 154 tons of total hydrocarbons, 56 tons of sulphur oxides, 470
                                        tons of carbon monoxide, and 2,857 tons of nitric oxides.

                            (7)    Eight crude oil spills greater than 1 and less than or equal to 50 bbl are projected to
                                   occur, but none will reach land.

                            (8)    Fewer than 10 crude oil spills greater than one and less than 50 bbl are assumed to
                                   occur from onshore support activities.

                            (9)    Total employment from all activities associated with the exploration, development, and
                                   production of oil and gas generated as a result of Sale 143 is 24,000 personnel, 45
                                   percent of which will be directly employed.

                      It should be noted that the assumptions and estimates for Alternative B are the same as in the Base Case
                  of Alternative A- Alternative B is essentially Alternative A minus 73 widely scaltered bk)cks (representing
                  about 1.7 percent of the blocks to be offered under Alternative A). (As in Alternative A, the two deferred
                  blocks at the Flower Gardens would also be deferred under this alternative.) Due to the scattered nature
                  of the blocks that would not be offered by this alternative, resource estimates for Alternative B do not differ
                  from those estimated for Alternative A. To the extent that adoption of Alternative B, by reducing the blocks
                  available for leasing, reduces the activities resulting from the leasing, these assumptions and estimates win be
                  similarly reduced. For instance, it may be reasonable to assume that one off or gas field may be present in    * one
                  or more of the blocks not offered under Alternative B. As discussed in Section W.A., not conducting
                  exploration or development activities on that field (because the blocks are not part of the sale area under this
                  alternative) could possibly result in the following activities not happening (which might otherwise occur under
                  Alternative A): 2-4 exploration wells with the disturbance of 1.5 ha of seafloor per well; 1 platform with the
                  disturbance of 2 ha of seafloor (4 ha in water deeper than 1,500 feet); 12 development wells from that
                  platform; 8 kin of gathering pipeline for that platform; no anchoring, pipeline burial, or sediment disturbance
                  will occur in the block; no use of service vessels or helicopters to and from that block will be required; no
                  discharges of drilling muds (7,134 bbl per exploration well, 6,749 bbl per development well), drill cuttings (1,853
                  bbl per exploration well, 1,430 bbl per development well); no discharge of produced waters (450 bbl per oil











                                                                                                                                11-53


               well per day, 68 bbI per gas well per day); no air emissions; and no chance for oil and gas industry-related
               accidents.
                   The primary difference between Alternative A (with consideration of the Topographic Features Stipulation
               for this analysis) and Alternative B (which excludes the blocks affected by the proposed stipulation) is that
               under Alternative B oil and gas activities would be completely excluded from taking place within the blocks
               which, under Alternative A, activities could take place (although with certain restrictions in certain portions
               of the blocks). Figure 111-5 shows a topographic feature with its attendant No Activity Zone, 1 Mile Zone, and
               3 Mile Zone. Under Alternative A, all those blocks containing any of those zones could be leased, although
               no oil and gas activities would be permitted in the No Activity Zone and activities would be restricted in the
               I and 3 Mile Zones. Under Alternative B, none of those blocks containing any of those zones would be leased,
               thus precluding any oil and gas activities anywhere in those blocks.

               b. Summary of Impacts

                   The following summarizes the detailed impact analyses of Section IV.D.2.b. It should be emphasized that
               these are impact summaries and that the reader should refer to Section IV.D.2.b. for detailed information
               regarding particular resources. Table S-4 compares the impacts of Alternatives A-D and the cumulative
               impacts on each resource category estimated as a result of the various scenarios.
                   To facilitate the analyses, the Federal offshore area is divided into subareas. The WPA is comprised of
               three subareas (W-1, W-2, and W-3) and the coastal region is divided into two coastal subareas (W-1 and W-2).
               These subareas are delineated on Figure IV-1.
                   This alternative is offered for the Secretary's consideration to protect valuable offshore biological resources.
               It affects the biologically sensitive banks (topographic features) of the Western Gulf.
                   Given the size of the area available for lease under Alternative A, it is reasonable to assume that the
               removal of 1.8 percent of the area probably will not significantly change the projected level of activity (i.e.,
               numbers of wells, platforms, vessel trips, etc. (Table IV-2)) projected under that alternative. The only
               differences are that under Alternative B no activity will take place in the deletion areas. The assumption that
               the levels of activity for Alternative B are virtually identical to those projected for Alternative A indicates that
               the impacts expected to result will be very similar to those described under Alternative A (Section IV.D.2.a.).
               The areas that would not be offered under Alternative B make up only a small portion of the WPA, and with
               the exception of topographic features, only contain comparatively small amounts, if any, of the resources
               analyzed in this document. Therefore, the regional impacts for all resources are estimated to be identical to
               those described under Alternative A. However, there are some localized changes in the impacts as described
               below.


               Coastal Resources


                   Coastal resources include beaches, seagrass beds, salt and fresh marshes, and estuaries. The beaches serve
               as important recreational sites in addition to storm protection and erosion control areas. The marshes and
               estuaries support numerous commercially and recreationally important fish and wildlife species. The primary
               impact-producing factors of concern for these environmental resources are contact by oil spills and disturbance
               from the emplacement of pipelines or the dredging of channels.
                   The areas that would be deleted from the proposed sale with the selection of Alternative B are scattered
               across the shelf far from the coastline. A small percentage of the area available for deletion is located, at its
               closest point, about 56 krn (35 mi) offshore. The majority of the acreage that may be deleted is over 160 km
               (100 mi) offshore. Considering the assumption that the estimated level of activity will not change from that
               projected for Alternative A and the substantial distances from the deletion areas to coastal resources, it is
               extremely unlikely that selection of Alternative B would have any influence on the impacts estimated for
               Alternative A.











                  11-54


                  Conclusion


                       The impacts on the following coastal resources are estimated to be the same as those estimated under
                  Alternative A. coastal barriers; wetlands; coastal and nearshore water quality; air quality; coastal and marine
                           i
                  birds (nonendangered and nonthreatened and endangered and threatened); recTeationall beach use; and
                  population, labor, and employment

                  Offshore Resources

                       Deletion of this area would preclude drilling operations and associated activities from occurring within the
                  87 affected blocks. It would further eliminate the threat of damage from drilling discharges, anchoring, or
                  platform/pipeline emplacement and removal related to the exploration and development of this area. The
                  following analyses deal specifically with the sensitive resources that may exist in the deletion area and for which
                  there might be a change in impacts with the selection of Alternative B. Deep-water benthic communities are
                  not located in or near the area, and only 12 blocks containing potential archaeological resources would not be
                  offered under this alternative that would be offered under Alternative A, so there would be no change in the
                  impact level projected under Alternative A. Impact to commercial fisheries and recreational marine fishing
                  would also remain as under Alternative A.


                       Topographic Features

                       Essentially, oil and gas operations within certain distances of topographic features are considered potential
                  sources of impact to the biota of those features: blocks that fall within 4 nmi of the 100-m isobath of the East
                  and West Flower Garden Banks; within 3 nmi of the 85-m isobath of the seven high-relief, shelf edge banks
                  of the Western Gulf (and 5 banks of the Central Gulf that are within 3 nmi of the Western Gulf); within 1,000
                  m of seven low-relief South Texas banks; and within designated areas of seven other low-relief banks. The
                  biological resources of the topographic features are considered very sensitive to potential impacts due to off
                  and gas operations; however, topographic features in the Western Gulf are usually the surface expressions of
                  salt domes, which are often associated with oil and gas reserves. The recovery of such reserves, the extent of
                  which is unknown at this time, would be prevented by the adoption of this alternative. It is noted that 113 of
                  the 200 blocks affected are already leased. This deletion alternative is presented in order to fully protect the
                  biological resources inhabiting the crests of the topographic features.
                       This alternative, if adopted, would prevent any oil and gas activity whatsoever in the affected blocks (except
                  for pipeline construction, which would be regulated through the normal pipeline permitting procedures); thus,
                  it would eliminate any impacts to the biota of the area from oil and gas activities, which otherwise would be
                  conducted within the blocks. However, because of the operation of the proposed Topographic Features
                  Stipulation, which is a part of Alternative A (Section II.B. l.c. (1)), the impact levels to the topographic features
                  will be essentially the same for both Alternative A and Alternative B.

                       Conclusion


                       Selection of Alternative B would preclude oil and gas operations in the unleased blocks (87 of 200) affected
                  by the proposed Topographic Features Stipulation. The activities assumed for Alternative 13 are expected to
                  cause little to no damage to the physical integrity, species diversity, or biological productivity of the habitat of
                  the topographic features of the Gulf of Mexico. Small areas of 5-10 m2 would be impacted, and recovery from
                  this damage to pre-impact conditions is expected to take less than 2 years, probably on the order of 24 weeks.

                       Mafine Water Quality

                       The impact-producing factors leading to water quality degradation resulting from offshore OCS oil and gas
                  operations include the resuspension of bottom sediments through exploration and development activities,
                  pipeline construction, and platform removal operations; the discharge of deck drainage, sanitary and domestic











                                                                                                                                  11-55


                wastes, formation waters (produced waters), and drilling fluids (muds and cuttings); and accidental
                hydrocarbon discharges due to spills, blowouts, or pipeline leaks. Routine operational discharges may degrade
                water quality with high impacts occurring within a few meters to tens of meters from the source. These impacts
                decrease to very low with distance (500-1,000 m) from the source. Accidental oil spills may degrade water
                quality somewhat, changing the measurements from background levels only in a very limited area close to the
                source. Adoption of this alternative would preclude impacts associated with routine exploration and production
                activities in the area not offered. It would not eliminate the threat of degradation from those OCS activities
                occurring outside the area not offered. However, because the area not offered is a small portion of the entire
                area offered for leasing under either Alternative A or Alternative B, the regional impact will be reduced by
                only that small amount, assuming that oil and gas activities would be reduced proportionally.

                     Conclusion

                     Selection of Alternative B would eliminate potential impacts on very localized areas contained in the
                deletion area, but this would not be significant enough to change the regional impact level on marine water
                quality as projected under Alternative A.

                     Cetaceans and Mafine nrdes


                     As benthic feeders, adult loggerhead, green, hawksbill, and Kemp's ridley sea turtles are unlikely to occur
                in the proposed deletion area because the topographic features in the CPA and WPA are at depths in excess
                of 300 m, which is the lower limit of the feeding habitat for these species. However, the pelagic stages of an
                sea turtles could occur in the vicinity of any of these areas. Sperm whales have been sighted near topographic
                features in the CPA and several of the more common small marine mammals--Stenella, Kogia, and Grampus--
                could be expected in the vicinity of topographic features because of the presence of prey species. Sea turtles
                and marine mammals could be impacted by oil and gas activities in this area by contact with or ingestion of
                oil, collision with vessels, entanglement in or ingestion of debris generated from platforms, or physical/acoustic
                disturbances (drilling and structure placement and removal). Not offering this area would eliminate all impacts
                to sea turtles and marine mammals that would otherwise occur from proposed action-related oil and gas
                operations within the blocks not offered. If the area is not offered, impacts to marine mammals and sea turtles
                will not change from those of the proposed action because of the comparatively low level of oil and gas activity
                proposed in the area.

                     Conclusion


                     Selection of Alternative B would eliminate potential impacts on endangered species and marine mammals
                in or near the area that would not be offered under this alternative. This slightly smaller number of blocks to
                be offered would not be significant enough to change the regional impact level on these resources as projected
                under Alternative A- These impacts are as follows: marine mammals - sublethal effects that occur periodically
                and result in short-term physiological or behavioral changes, as well as some degree of avoidance of the
                impacted area(s); marine turtles - sublethal effects that are chronic and could result in persistent physiological
                or behavioral changes.

                3. Alternative C - The Proposed Action Excluding the Western
                     Naval Operations Area

                a. Description

                     The proposed alternative would delete 340 lease blocks (approximately 1.7 million acres) in the Western
                Naval Operations Area located east of Corpus Christi, Texas (Figure 1-1). In late 1990, MMS and the
                Department of Defense (DOD) agreed to the deferral of this area from Western Gulf lease Sale 135 (held in











                  11-56


                  August 1991) and proposed Western Gulf lease Sale 141 (scheduled for August 19SQ). It was also agreed that
                  the defe 'rral would be subject to a two-year review period, after which a decision would toe made to either
                  continue the deferral for another two years or move the area to another acceptable location. Consultation has
                  begun between DOD and MMS, and negotiations are continuing regarding this deferral area. Since
                  negotiations regarding this matter are still ongoing, the deletion of this 340-blockarea is included in this EIS
                  as a separate alternative.

                  b. Summary of Impacts

                      The following summarizes the detailed impact analyses of Section IV.D.2.c. It should be emphasized that
                  these are impact summaries and that the reader should refer to Section IV.D.2.c. for detailed information
                  regarding particular resources. Table S4 provides a comparison of impacts related to Alternatives A-D and
                  the cumulative impacts on each resource category estimated as a result of the various scenarios.
                      Given the size of the area available for lease under the proposed alternative and the distribution of the
                  resources contained within, it is reasonable to assume that removal of this area will not significantly change the
                  projected level of activity (i.e., numbers of wells, platforms, vessel trips, etc. (Table IV-2)) projected under
                  Alternative A. Alternative C will preclude all leasing and sale-related activity from occurring in the area
                  deleted. It will not preclude the threat from activities associated with oil and gas resource development outside
                  this area. Shuttle tankering and pipeline construction may still occur in the area from such activities. The
                  assumption that the levels of activity for Alternative C are virtually identical to those projected for Alternative
                  A indicates that the impacts expected to result will be very similar to those described under Alternative A
                  (Section IV.D.2.a.). The regional impacts for all resources are estimated to be identical to those described
                  under Alternative A, with only some localized changes in the impacts as described below.

                  Coastal Resources


                      The majority of the acreage proposed for deletion is from 80-160 kin (50-100 mi) offshore. Considering
                  the estimated level of activity will not change from that projected for Alternative A and the distances from the
                  deletion area to coastal resources, it is unlikely that selection of Alternative C would have any influence on the
                  impacts to coastal resources expected for Alternative A-

                  Conclusion


                      The impacts on the following coastal resources are expected to be the same as those expected under
                  Alternative A. coastal barriers; wetlands; coastal and nearshore water quality-, air quality; coastal and marine
                  birds (nonendangered and nonthreatened and endangered and threatened); recreational beach use; and
                  population, labor, and employment.

                  Offshore Resources

                      Deletion of this area would preclude drilling operations and associated activities from occurring within
                  some 340 affected blocks. It would further eliminate the threat of damage from drilling discharges, anchoring,
                  or platform/pipeline emplacement and removal related to the exploration and development of this area. The
                  following analyses deal specifically with the sensitive resources that may exist in the deletionarea and for which
                  there might be a change in impacts with the selection of Alternative C. No topographic features are located
                  in or near the area, and only 12 blocks containing potential historic archaeological resources would not be
                  offered under this alternative that would be offered under Alternative A; therefore, there would be no change
                  in the impact level projected under Alternative A. Impact to commercial fisheries and recreational marine
                  fishing would also remain as under Alternative A.











                                                                                                                                11-57


                   Deep-water Benthic Communities

                   As noted in Section IV.D.2.a.(2)(a), the only impact-producing factor threatening these communities results
               from those activities that would physically disturb the bottom, such as the routine operations of anchoring,
               drilling, and pipeline installation, and the rare seafloor blowout accident.
                   The proposed alternative differs from Alternative A by offering all of the blocks of Alternative A except
               for approximately 340 blocks that comprise the Western Naval Operations Area (Figure I-1). Of these blocks,
               all or part of 197 blocks are in water depths below 400 in, with 6 of these under active lease. Thus, if
               Alternative C is adopted, those blocks would not be subject to the potential impacts described for Alternative
               A (Section IV.D.2.a.(2)(a)). Not leasing these 191 unleased blocks (6% of the 3,104 unleased blocks in water
               depths below 400 in in the WPA) will not alter the conclusions reached in the analysis for Alternative A.
                   The majority of these deep-water communities are of low density and are widespread throughout the deep-
               water areas of the Gulf, and disturbance to a small area would not result in a major impact to the ecosystem.
               For purposes of this analysis, the frequency of such impact is expected to be once every six months to two
               years, and the severity of such an impact is judged to result in few losses of ecological elements with no
               alteration of general relationships.
                   Such communities are largely protected by the provisions of NTL 88-11. For purposes of this analysis, the
               frequency of some small percentage of impact is expected to be once every six months to two years, but the
               severity of such an impact is such that there may be some loss of ecological elements and/or some alteration
               of general relationships.

                   Conclusion


                   Alternative C is expected to cause little damage to the physical integrity, species diversity, or biological
               productivity of either the widespread, low-density chemosynthetic communities or the rare, widely scattered
               high-density Bush Hill-type chemosynthetic communities. Recovery from any damage is expected to take less
               than two years.

                   Marine Water Quality

                   The impact-producing factors leading to water quality degradation resulting from offshore OCS off and gas
               operations include the resuspension of bottom sediments through exploration and development activities,
               pipeline construction, and platform removal operations; the discharge of deck drainage, sanitary and domestic
               wastes, formation waters (produced waters), and drilling fluids (muds and cuttings); and accidental hydrocarbon
               discharges due to spills, blowouts, or pipeline leaks. Routine operational discharges may degrade water quality
               with high impacts occurring within a few meters to tens of meters from the source. These impacts decrease
               to very low with distance (500-1,000 in) from the source. Accidental oil spills may degrade water quality
               somewhat, changing the measurements from background levels only in a very limited area close to the source.
               Adoption of this alternative would preclude impacts associated with routine exploration and production
               activities in the area not offered. It would not eliminate the threat of degradation from those OCS activities
               occurring outside the area not offered. However, because the area not offered is a small portion of the entire
               area offered for leasing under either Alternative A or Alternative C, the regional impact level will be reduced
               by only that small amount, assuming that oil and gas activities would be reduced proportionally.

                   Conclusion


                   Selection of Alternative C would eliminate potential impacts on very localized areas contained in the
               deletion area, but this would not be significant enough to change the regional impacts on marine water quality
               expected under Alternative A-










                   11-58


                        Cet4ceans and Marine nriles


                        Sea turtles and marine mammals could be impacted by oil and gas activities in this area by contact with
                   or ingestion of oil, collision with vessels, entanglement in or ingestion of debris generated from platforms, or
                   physical/,acoustic disturbances (drilling and structure placement and removal). Not offering this area would
                   eliminate all impacts to sea turtles and marine mammals that would otherwise occur from proposed action-
                   related oil and gas operations within the blocks not offered. If the area is not offered, impacts to marine
                   mammals and sea turtles will not change from those of the proposed action because of the comparatively low
                   level of oil and gas activity proposed in the area.

                        Conclusion


                        Selection of Alternative C would eliminate potential impacts on endangered species and marine mammals
                   in or near the area that would not be offered under this alternative. This smaller number of blocks to be
                   offered would not be significant enough to change the regional impacts on these resources expected under
                   Alternative A. These impacts are as follows: marine mammals--sublethal effects that occur periodically and
                   result in short-term physiological or behavioral changes, as well as some degree of avoidance of the impacted
                   area(s); and marine turtles--sublethal effects that are chronic and could result in persistent physiological or
                   behavioral changes.

                   4. Alternative D - No Action

                   a. Description

                        The alternative is equivalent to cancellation of a sale scheduled on an annual basis. By canceling the
                   proposed sale, the opportunity is postponed or foregone for development of the estimated 0.05 BBO and 0.74
                   tcf of gas that could have resulted from proposed Sale 143 in the Western Gulf.

                   b.- Summary of Impacts

                        If Alternative D is selected, all impacts, positive and negative, associated with the proposed action would
                   be canceled. This alternative would therefore result in no effect on the sensitive resources and activities
                   discussed in Section IV.D.2.a. The incremental contribution of the proposed action to cumuhitive effects would
                   also be foregone, but such effects from other activities, including other OCS sales, would remain. One
                   contribution to cumulative effects that could increase is oil spill risk due to the importation of foreign oil to
                   replace the resources lost through cancellation of the proposed action.
                        Alternative energy strategies that could provide replacement resources for lost domestic OCS oil and gas
                   production include energy conservation; conventional oil and gas supplies; coat nuclear power; oil shale; tar
                   sands; hydroelectric power; solar and geothermal energy-, and imports of oil, natural gas, and LNG. These are
                   discussed in some detail in Appendix D. The energy equivalents that may be required fromseveral alternative
                   energy sources, should this lease sale be permanently canceled, are shown on Table D-8 and are based on the
                   resources estimated by MMS to be produced as a result of the proposed action. For the purpose of clarity,
                   this table has separately identified each potential alternative source of energy regarding substitution
                   requirements. It is unlikely, however, that there would be a single choice between these alternatives sources,
                   but instead, some combined effort to explore and develop further many or an of these forms as a substitute
                   for OCS off and gas production.











                                                                                                                    11-59

             5. Comparison of Alternatives

                 Table S4 provides a comparison and summary of the impacts of the proposed action (Alternative A), the
             proposed action excluding the blocks near biologically sensitive topographic features (Alternative B), the
             proposed action excluding the western naval operations area (Alternative C), no action (Alternative D), and
             the cumulative analyses for Sale 143.












   SECTION III
    DESCRIPTION OF THE            11-F
    AFFECTED ENVIRONMENT











                                                                                                                           111-3

              111. DESCRIPTION OF THE AFFECTED ENVIRONMENT

              A. PHYSICAL ELEMENTS OF THE ENVIRONMENT

              1. Geology

              General Description

                  Geology of the Central and Western Gulf of Mexico is shown on Visual No. 6, and the general sediment
              distribution is shown on Visual No. 5. Shedding of sediments from the Laramide Orogeny and the North
              American Craton resulted in deposition of a thick, terrigenous, clastic sequence in the Gulf Coast basin. If rate
              of deposition exceeds rate of subsidence, deltas prograde out over the continental shelf, and the sediments are
              redistributed over the shelf through wave action and currents. If sedimentation is less than subsidence, then
              a transgression results and the deltas are modified by marine processes (Shinn, 1971).
                  Since late Cretaceous and early Tertiary, depocenters shifted progressively southward and eastward along
              the Gulf Coast (Winker, 1982). The locus of deposition shifted laterally in response to changes in source of
              sediment supply. Lower Tertiary deposits are thickest in the Rio Grande embayment. By late Miocene,
              depocenters had shifted farther south and east, forming the "Terrebonne Trough" in southern Louisiana.
                  Regional dip of sediments of the Gulf of Mexico is interrupted by salt diapirs, growth faults, and shale
              diapirs. Regional systems of growth faults penetrate into the Cenozoic units beneath coastal Texas and
              Louisiana and the adjacent shelf. Growth faults, formed contemporaneously with sedimentation, resulted in
              throws increasing with depth and strata on the downthrown side thicker than on the upthrown side. The faults
              resulted from simultaneous failure of the slope from deltas that had prograded to the edge of the continental
              margin (Martin et al., 1984).
                  The prospective horizons of the northwestern continental shelf are of Miocene, Pliocene, or Pleistocene
              age. The environment of deposition of the continental shelf and slope in the northern Gulf of Mexico is one
              of the most significant factors controlling hydrocarbon production. Sediments deposited on the outer shelf and
              upper slope have the greatest potential for accumulating hydrocarbons. This environment is the optimum zone
              for encountering the three ingredients necessary for the successful formation and accumulation of oil and gas:
              reservoir rock, source beds, and traps. Sediments deposited on the outer shelf and upper slope have the
              greatest potential for bearing hydrocarbons due to the following three reasons: (a) this is the location where
              nearshore sands interfinger with the deeper water marine shales, providing an optimum ratio of sandstone to
              shale--the shale may be the source rock that provides the oil and gas while the sandstone provides the reservoir
              into which the hydrocarbons migrate and are trapped; (b) in this environment, the organic material deposited
              with the fine-grained clays and muds is preserved and not oxidized as it might be in more shallow, turbulent
              water; and (c) it is this location where the increased overburden of prograding shallow marine deposits over
              plastic salt and marine shales initiates the flow of salt that triggers the growth of salt domes and regional
              expansion faults, that provide traps for the hydrocarbons.
                  The most prolific offshore production to date in the Gulf has come from the Miocene of the eastern
              Louisiana OCS. This area has more oil than the remainder of the Texas-Louisiana area. The next most
              productive trend is the Pliocene trend of the central Louisiana OCS, which produces about 50 percent off and
              50 percent gas. Farther to the west, this producing trend dies out. The Miocene of western Louisiana is the
              third most productive trend, producing primarily gas, and the Pleistocene of offshore western Louisiana ranks
              fourth.
                  Recently, a number of oil and gas discoveries have been made along the shelf and upper slope offshore
              of Louisiana and Texas in Pleistocene sediments known as the Flexure Trend. On the upper slope, interdomal
              areas between salt structures contain a thickness as great as 3,500 in of sediment, much of which appears to
              be muddy slump deposits with infrequent turbidite sand zones. Some of the new discoveries indicate that
              turbidite sands of reservoir quality are present on the upper slope, especially in Pleistocene deposits. These











                    111-4

                    turbidite sands would have been derived from inner-shelf areas and deposited during glacial. epochs when sea
                    level was lower and the shoreline was close to the present shelf edge.
                         An MMS-funded study (Berryhill, 1987) has investigated the spatial and vertical dimensions of Late
                    Quatern,hry facies that occur on the continental shelf and upper slope of the northern Guff of Mexico. This
                    effort was the first comprehensive study of a continental shelf that relied on high-resolution seismic data as the
                    primary data source. The results of the study were based on analyses of 145,000 km of subbottom proffier and
                    72,000 km of minisparker data. The study presents late Quaternary seismic-reflection models that can be used
                    as exploration tools and demonstrates the interactions and processes that are involved among sediment
                    deposition, diapirism, and sea-level fluctuations in the building of the continental shelf.

                    Geologic Hazards

                         Major hazards to oil and gas development are associated with geologic features on the Gulf of Mexico
                    seafloor that result in its instability. These hazards present many operational limitations to the exploration and
                    development of oil and gas. Seafloor instabilities necessitate adaptations in the siting and structural engineering
                    of pipelines, drilling rigs, and production platforms.
                         Various conditions can result in sediment mass wasting. The basic criterion, known as the "angle of slide,"
                    is a combination of slope and the consolidation of sediments. Sediments at angles less than 0.50 have been
                    known to fail in the Gulf of Mexico because of their underconsolidation. Seismic activity, overloading, cyclic
                    loading, and migrating shallow gas can drastically reduce the necessary angle of slide for given sediments and
                    can even cause liquefaction in horizontal sediments. Currents in submarine canyons can undercut canyon walls,
                    and uplift, associated with diapirs, can oversteepen the slope allowing sediments to slump, slide, or generate
                    turbidity currents.
                         Fine-grained sediments that retain pore fluids produce sediment instability that results in slumping and
                    mudflows. Rapid deposition of these sediments prograding out of the Mississippi River is the primary cause
                    of abnormally high pressures in the Gulf Coast Pore fluids trapped in sediment help framework grains support
                    the overburden, thereby restricting compaction. Normally pressured sediments compact with the extrusion of
                    saline pore fluids from the shales.
                         Sediments of fine-grained sands and clays, retaining high amounts of water and organic matter, contain
                    large quantities of interstitial gas that often degrade the seismic signal. Shallow gas may weaken shallow
                    geologic formations, providing avenues of escape for high pressure fluids and gas from deeper formations.
                    Dissolved or undissolved gas either dispersed or in pockets can also be a serious problem to platforms,
                    supports, pipelines, and subsea installations. Gas-charged sediments can contribute to low shear strength or
                    promote liquefaction. Storm surges or seismic shaking, coupled with an upward release of gas, could trigger
                    slides and subsidence. Their identification is important to any drilling program because of the danger of
                    ignition or blowout
                         A delta front slope prograding from the mouths of distributaries can also produce geologic hazards.
                    Oversteepening of the upper delta front slope occurs as the delta front migrates out to the continental slope.
                    Strong storms and hurricanes generate much sediment movement at depth causing sediment instability.
                    Additionally, hurricanes can generate mudslides along the delta front After destructive Hurricane Camille in
                    1969, USGS published a map showing bottom sediment stability along the periphery of the Mississippi delta.
                         Furthermore, mudslides produce geologic hazards that can be a serious problem, to pipelines. One method
                    to combat mudslides is to allow pipelines to be laid in the direction of the flow of mud (USDOI, BLM, 1982).
                    Additionally, pipelines are laid on top of mudflows rather than allowed to sink into the sediments. Engineering
                    technology and improved soil borings by the oil industry have made drilling safer in rnudslide environments and
                    other domains susceptible to geologic hazards.

                    Deepwater Geologic Hazards

                         A small investment to evaluate possible geologic hazards on the continental shelf/slope. and more distal
                    regions is essential before funding expensive deep-water operations. The shedding of sediments from the
                    Appalachians and the North American craton resulted in deposition of a thick terrigenous clastic sequence in











              the Gulf Coast basin. These sediments were deposited over the Louann salt with lower density salt having
              flowed both basinward and upward through the overlying sediments. These events have resulted in a myriad
              of geologic hazards.
                  Active faults on the continental slope are a result of the upward movement of salt through overlying
              sediments. The Tate and timing of movement of the faults is difficult to ascertain (Roberts, 1991). Another
              geologic hazard identified with salt diapirs is slumping that is associated with the steep flanks of these geologic
              features. Other geologic hazards to avoid on the shelf/slope are carbonate mounds. Carbonate mounds are
              situated on the crests of salt diapirs. These mounds were near sea level during the last major low stand and
              these features are interpreted as "seismic wipeout" zones on subbottom profiles (Roberts et al., 1988). Both
              rapid changes in topography and isolated carbonate mounds with steep flanks also present problems when
              laying pipelines or installing a platform. Biogenic and thermogenic gas are also construed as "seismic wipeout"
              features. Bacteria produce biogenic: gas from organic matter whereas thermogenic gas is generated deep in
              the subsurface under high temperatures and pressures. Thermogenic gas migrates updip towards the surface
              along fault planes.
                  To avoid these geologic hazards, industry invests in ROV's, conventional cores, subbottom profiles, and
              side-scan sonar. The geophysical and geological data acquired is invaluable and necessary to properly evaluate
              the deeper regions of the Gulf of Mexico.

              Non-Oil and Non-Gas Mineral Resources

                  Several minerals in the Central Gulf of Mexico have the potential to become commercially exploitable.
              The State of Louisiana is mapping sand deposits to determine shoreline restoration. Most of these deposits
              occur in State waters, but some potential deposits have been found in Federal waters. Ship Shoal, a large sand
              shoal seaward of the Isles Dernieres, contains a high qualtity sand that could be mined for coastal restoration
              and protection against accelerating rates of wetland loss (Byrnes and Groat, 1991). Deposits of quartz sand
              in Federal and State waters off the coasts of Mississippi and Alabama are of interest because of their potential
              use in the production of glass. Sulphur and salt deposits associated with the diapiric structures beneath the
              OCS seafloor have mining potential. The Caminada sulphur mine in Federal waters has recently been
              activated, and DOI conducted an offshore sulphur lease sale on February 24, 1988.
                  In addition, known mineral resources in adjacent coastal areas include phosphate, quartz, sand, sulphur,
              salt, oyster-shell, limestone, sand and gravel, and magnesia. As part of the national initiative to develop the
              marine mineral resources of the OCS, MMS is working with the Gulf Coast States to complete preliminary
              economic reconnaissance studies of nonenergy marine minerals. These efforts began during the summer of
              1987. During the Ninth Annual Gulf of Mexico Information Transfer Meetings, sponsored by MMS in October
              1988, participating states presented progress reports on these efforts in a session entitled Marine Mineral
              Resources in the Northern Gulf of Mexico (USDOI, MMS, 1989a).

              2. Meteorological Conditions

              General Description

                  The Gulf of Mexico and adjacent coastal areas are part of the Atlantic tropical cyclone basin. Because
              of its extensive coastal region and almost complete enclosure by land, the Gulf is also a favorable region for
              the development of atmospheric disturbances associated with land and sea-surface-temperature contrasts. The
              area has two well-defined seasons; the summer (May-October) and winter (December-March). The two
              transitional months are April and November. In winter the Atlantic high moves southward and creates a
              clockwise wind field. The polar front also moves southward and brings cold fronts into the region at 3- to 10-
              day intervals. In summer the subtropical gyre decreases in size and moves northward allowing the northeast
              trade winds to reach northwards and influence the entire Gulf. The polar front returns to its northern position
              preventing the cold fronts from reaching the Gulf region. The northward penetration of the trade winds makes
              it possible for tropical cyclones and hurricanes to come into the Gulf.











                  111-6

                  Pressure, Temperature, and Relative Humidity

                       The western extension of the Azores-Bermuda high-pressure cell dominates circulation throughoutthe year,
                  weakening in winter and strengthening in summer. The average monthly pressure shows a w,.st to east gradient
                  along the northern Gulf during summer; minimum at Texas (1,013.85 millibars (mb)) and maximum at Florida
                  (1,016.67 mb). In winter the monthly pressure is more uniform along the northern Gulf-, most of the pressure
                  is around 1019 mb and slightly lower in southern Texas (1,018 mb). The minimum average monthly pressure
                  occurs during the summer when the equatorial trough shifts northward. The maximum pressure occurs during
                  the winter as a result of the presence and influence of continental cold air.
                      Average air temperatures at coastal locations vary with latitude and exposure. Seasonally, air temperatures
                  at coastal areas are highest in summer (from 24.69 to 27.961C), with the highest temperatures occurring in
                  south Florida. In winter, air temperature is at a minimum (from 12.05 to 21.73'C):, with the coldest
                  temperatures in Alabama. Winter temperatures depend on the frequency and intensity of penetration by polar
                  air masses from the north. These incursions, when they bring strong northerly winds, are called "northers"and
                  may occur some 15-30 times between November and March. Air temperatures over the open Gulf exhibit
                  narrower limits of variations on a daily and seasonal basis. The average temperature over the center of the
                  Gulf is about 29C in the summer; winter temperatures average between 17' and 23*C.
                      The relative humidity over the Gulf is high throughout the year. Minimum humidities occur during the
                  late fall and winter when cold, continental air masses bring dry air into the northern Gulf. Maximum humidities
                  occur during the spring and summer when prevailing southerly winds bring in warm, moist air. Therecording
                  stations from Brownsville, Texas, to Key West, Florida, show the relative humidity varies annually from a high
                  of 87 percent at 6:00 a.m. to a low of 44 percent at noon. This variation in a 6-hour period is caused by daily
                  warming.

                  Surface Wuzds


                      Winds are more variable near the coast than over open waters because coastal winds are more directly
                  influenced by the moving cyclonic storms that are characteristic of the continent and because of the sea- and
                  land-breeze regime. The Azores-Bermuda atmospheric high-pressure cell dominates circulation over the Gulf,
                  particularly during the spring and summer months. In late summer, there is a general northward shift of the
                  circulation, and the Gulf becomes more directly influenced by the equatorial low-pressure, cell. During the
                  relatively constant summer conditions, the southerly positions of the Azores-Bermuda cell generates
                  predominantly southeasterly winds, which become more southerly in the northern Gulf. In the CPA, inshore
                  wind components during summer have a frequency of 52-85 percent with average speeds between 4 and 6 ms-1.
                  In the WPA, summer inshore components have a frequency of 38-61 percent with speeds of 3-5 ms-1. Winter
                  winds usually blow from easterly directions with fewer southerlies but more northerlies. Winds from the west
                  and southwest are rare at anytime during the year. The inshore components during winter in the CPA have
                  a frequency of 47-64 percent with speeds of 4-5 ms-1, and offshore components occur 19-34 percent of the time.
                  In the WPA the inshore wind component frequency is 26-37 percent with speeds of 4-6 ms-1; the offshore
                  components occur 45-55 percent of the time with speeds of 4-8 ms-1. Annual average wind speeds at other
                  coastal areas in the Gulf of Mexico can be found in Table III-1.

                  Precipitation and Visibility

                      Average annual precipitation along the Gulf Coast ranges between approximately 69 cm in Brownsville,
                  Texas; 102 cm at Galveston, Texas; and 137 cm at New Orleans, Louisiana, and Fort Myers, Florida. Other
                  annual averages of precipitation in the coastal areas of the Gulf can be found in Table III-1. With the
                  exception of the South Texas region, rainfall is fairly evenly distributed throughout the year, with the greatest
                  amounts occurring during June, July, and August when the winds are predominantly out of the south and
                  southeast.


















                                                                                               Table 111-1


                                                                       Climatological Data for Selected Gulf Coast Locations


                                                Precipitation     Temperature        Wind Speed          Humidity          Barometric                     Stability Conditions
                                                   (Annual            (Mean            (Average          (Average          Pressure                         Annual Percent
                   Location                       Average)           Annual         Annual Mean)         Percent)     (Average Annual) Unstable                 Neutral            Stable
                                                    meters          Degree C)             ms-I

                   Corpus Christi, Tex.              0.77              21.7               5.4               89             1,014 mb*            11.0              61.0               28.0

                   Galveston, Tex.                   1.07              20.9               4.9               83             1,015 mb             16.0              61.4               22.6

                   Lake Charles, La.                 1.35              19.9               3.9               90             1,016 mb             23.0              44.0               33.0

                   Gulfport, Miss.                   1.50              20.0               3.6               85             1,016 mb             17.5              47.4               35.1

                   Pensacola, Fla.                   1.55              19.9               3.7               85             1,013 mb             18.0              22.0               60.0

                   Key West, Fla.                    1.01              25.3               5.0               79             1,014 mb             80.0              18.0               2.0



                   *mb = millibar.


                   Sources: USDOC, NOAA, 1961-1986.











                  111-8

                      Precipitation is frequent and abundant throughout the year but does show distinct seasonal variation. In
                  New Orleans,   October is the only month when precipitation averages less than 8 crn; July is the wettest month
                  and receives just under 18 cm. Stations along the entire coast record the highest precipitation values during
                  the warmer months of the year. The warmer months usually have convective cloud systems that produce
                  showers and thunderstorms; however, these thunderstorms rarely cause any damage or have attendant hail
                  (USDOC, 1967; Brower et al., 1972). The month of maximum rainfall for most locations is July; however,
                  Brownsville's record maximum is in September. Winter rains are associated with the frequent passage of
                  frontal systems through the area. Rainfalls are generally slow, steady, and relatively continuous, often lasting
                  several days. Snowfalls are rare, and when frozen precipitation does occur, it usually melts on contact with the
                  ground. Incidence of frozen precipitation decreases with distance offshore and rapidly reaches zero.
                      Warm, moist Gulf air blowing slowly over chilled land or water surfaces brings about the; formation of fog.
                  Fog occurrence decreases seaward, but visibility has been less than 800 in due to offshore fog. Coastal fogs
                  generally last 3 or 4 hours, although particularly dense sea fogs may persist for several days. The poorest
                  visibility conditions occur during winter and early spring. The period from November through April has the
                  highest frequencies of low visibilities. On the South Texas coast, fog reduces visibility to less than 1,000 in on
                  an average of 28 days/year; very dense fog in Galveston reduces visibility to 600 in about 16 days/year; and Port
                  Arthur has an average of 42 days/year with visibility less than 600 in. Visibility around the Mississippi Delta
                  may be lowered by industrial pollution from New Orleans or by burning marshlands. The number of days that
                  visibility decreases to less than 400 in (heavy fog) in the Eastern Gulf decreases from 35 days/year in Pensacola
                  to 1 day/year at Key West.

                  Atmospheric Stability and Miring Height

                      Table 111-1 shows the frequency of atmospheric stability using the Pasquill classification at several coastal
                  locations along the Gulf area. Along the Texas coastal areas, stability is mainly either neutral (61% of the
                  time) or stable (22-28%); unstable conditions occur only 11-16 percent of the time. In Louisiana and
                  Mississippi the atmospheric stability is chiefly either neutral (44-47%) or stable (33-35%), and slightly more
                  frequently unstable (17-23%). Along Florida's northern coast the atmospheric stability is mainly either neutral
                  (22%) or stable (60%); unstable conditions occur rarely (18%). In southern Florida, the atmospheric is
                  unstable most of the time (80%), while neutral (18%) and stable (2%) occur rarely.
                      The mixing height is very important because it determines the space available for spreading the poUutants.
                  Because the mixing height is directly related to vertical mixing in the atmosphere, a mixed layer is expected
                  to occur under neutral and unstable atmospheric conditions. The mixing height does not exist under stable
                  atmospheric conditions. Although mixing heights information throughout the entire Gulf of Mexico is very
                  scarce, measurements near Panama City, Florida (Hsu, 1979) show that the mixing height can vary between
                  400 and 1,300 in, with a mean of 900 in. The mixing height tends to be lower in winter, and daily changes are
                  smaller than in summer. A climatology of mixing heights (Schulze, 1991) shows that in summer the afternoon
                  mean mixing height around Louisiana coastal areas is between 1,200 and 1,400 in, and between 1,400 and 1,600
                  in around the rest of the Gulf. In winter, the afternoon mean mixing height is over 800 in in Louisiana coastal
                  areas and between 8W and 1,000 in throughoutthe remaining Gulf area. The southern tip offlorida, however,
                  has mixing heights between 1,000 and 1,200 m.

                  Severe Storms

                      The most intense and destructive storms affecting the Gulf of Mexico and adjacent coastal zones are
                  tropical cyclones, which originate over the warm waters of the central Atlantic Ocean, Caribbean Sea, or the
                  Gulf of Mexico. Tropical cyclones occur most frequently between June and November. There is a relatively
                  high probability that cyclonic storms will cause damage to physical, economic, biological, and social systems in
                  the Gulf. These storms are categorized by the U.S. National Weather Service according to intensity. The most
                  intense storms, which are called hurricanes, have winds of greater than 121 kilometers per hour (km/h). The
                  determination of storm intensity at sea and in the coastal region is readily measured by current
                  weather-forecasting methods and surveillance techniques. Recorded historical data on past storms prior to 1950











                                                                                                                           111-9

               is often difficult to obtain. The probability of storm occurrence in certain coastal areas and meteorological
               disturbance intensity is discussed in BLM Open File Report 80-02 (USDOI, BLM, 1982) and is depicted on
               Visual No. 7.
                   Extratropical cyclones originate in middle and high latitudes, forming on the fronts that separate different
               air masses. These storms, which may vary greatly in intensity, occur primarily during the winter months and
               have attained wind speeds as great as 55-93 km/h. The Gulf of Mexico is an area of cyclone development
               during the cooler months due to the contrast in temperatures of the warm air over Gulf waters and the cold
               continental air over the United States.
                   Hurricanes have always posed a seasonal threat to the people of the Gulf of Mexico coastal region.
               Damages resulting from these violent storms have been noted as far back as the Spanish explorations by
               Columbus in the late 1400's. Five unidentified Spanish ships carrying unknown cargo were destroyed during
               a 1766 hurricane in the Bay of St. Bernard (Galveston Bay). In 1778, 14 unidentified large British ships
               carrying lumber to Jamaica were destroyed in Pensacola Harbor by a hurricane (CEI, 1977). Indianola, Texas,
               was struck by a hurricane in 1875; this resulted in the destruction of three-quarters of the town, and 176 lives
               were lost. Eleven years later Indianola was destroyed by another hurricane; the town was never rebuilt. In
               1900, Galveston, Texas, was the location of the worst hurricane disaster in the history of the Gulf of Mexico.
               Tidal surges were recorded at 4.6-6.1 m, more than 3,600 homes were destroyed, and 6,000-8,000 people lost
               their lives.
                   Hurricanes vary considerably in intensity, track patterns, and behavior when crossing land. McGowen et
               al. (1970) explain that storm approach is marked by rising tides and increased wind velocities; generally, the
               longer a storm lingers in the Gulf, the larger the surge of water it pushes ashore as it approaches land. These
               storm tides are commonly higher in the bays than on Gulf sea beaches, although flooding and pounding waves
               affect both areas. There is no preferred approaching route of hurricane tracks (DeWald, 1982), although early
               season storms generally approach from the southeast and later ones are more out of the south. Most
               hurricanes form in tropical ocean areas; however, some are generated in the Gulf of Mexico. From 1900 to
               1985, 64 tropical storms formed in the Gulf of Mexico, 32 of which became hurricanes (USDOC, NOAA, 1978,
               updated 1985).
                   Hurricane damage results from high winds and, particularly in the coastal areas, the storm surge or tide,
               which is an abnormally high rise in the water level. Maximum surge height at any location is dependent on
               many factors including bottom topography, coastline configuration, and storm intensity. Damages from severe
               storms include environmental losses due to shore and bay erosion, wildlife- and fisheries-habitat disruptions,
               and direct animal population loss; economic losses to oil and gas operations, the seafood industry, and vessel
               casualties; and social losses resulting from human displacement, property damage, and loss of life.
                   In recent years, hurricanes have had a great impact on offshore oil development in addition to posing
               threats to residents of coastal regions. Hurricane Camille (1969) caused 262 deaths, and tidal surges were
               recorded at 7 m in MississippL Three offshore platforms were affected; the first was completely destroyed, the
               second was severely damaged and removed from the offshore, and the third suffered damages but was repaired
               and reused in another area. The damage to these three platforms, plus 1,828 m of pipelines, exceeded
               million.
                   Other hurricanes that have caused destruction to offshore development are as follows: Hurricane Hilda
               (1964) destroyed six platforms; Hurricane Carmen (1974) caused four pipeline breaks; Hurricane Eloise (1975)
               caused one pipeline break; and Hurricane Bob (1979) caused one pipeline break (DeWald, 1982).
                   More than 500,000 people from Louisiana were evacuated in advance of Hurricane Elena (September
               1985). Although Elena caused millions of dollars worth of property damage, no deaths or serious injuries
               resulted. Winds were recorded up to 201 km/h, and at least 10 tornados were sighted. Over 110,000 homes
               and businesses were left without power.
                   Hurricane Elena caused severe coastal erosion and landloss along the Chandeleur Islands off Louisiana.
               Approximately 20 percent of the total island area was removed by the storm. On many parts of the island,
               vegetation was stripped and major dune fields were severely damaged. The northern end of the island near
               the lighthouse was partially destroyed, and many tidal channels were cut through the northern quarter of the
               island (Louisiana Geological Survey, 1985). Elena further affected the beaches and shores of the Florida west
               coast from Escambia County through Sarasota County, a shoreline distance of about 795 kin. Balsillie (1985)










                   III-10

                   performed a Type I erosion-value analysis relative to Hurricane Elena's effects on Florida's beaches and shores.
                   This was an average for sampled profiles where only erosion occurred. Through this analysis, it was determined
                   that beal ch and coast erosion volumes from Pinellas, Franklin, Gulf, and Escambia Counties ranged from 21
                   to 40 111@3 per shorefront meter of coast The average erosion was 25 m3 per meter.
                       Ninety percent of the Alabama oyster resources were lost as a result of Hurricane Elena. All major
                   reefs--Cedar Point, Buoy, and Kings Bayou--were impacted by extreme tidal activity, hurricane force winds, and
                   heavy iainfall from Hurricane Elena; and oyster populations were subjected to acut-- mechanical and
                   physiolo'. gical stress that may have drastically altered oyster population dynamics on impacted reefs. The most
                   productive reef, Cedar Point Reef (Mobile County), was virtually destroyed. Estimates were that restoration
                          I
                   of 479 ha of reef area by planting adequate cultch material should result in replacement of the lost oyster
                   resources within a period of 1.5-2.0 years, provided adequate spat set occurs (Tatum, 1985). Shellfish resources
                   in Apalachicola Bay (Franklin County) sustained severe damage. This bay system is vital to the oyster industry
                   of Florida--over 90 percent of Florida's oyster landings come from this bay. In 1984, approximately 900
                   oyster-harvesting licenses were issued in Franklin County. Damage assessment following the storm indicates
                   oyster populations on the bay's most productive reefs (Cat Point Bar and East Hole Bar) have been reduced
                   to levels that would not support commercial harvesting. Commercially harvestable concentrations of oysters
                   on Cat Point Bar were reduced to approximately 20 percent of the estimated harvestable oysters present before
                   the storm. Those resources on East Hole Bar were virtually eliminated (Berrigan, personal comm., 1986).
                       Hurricane Juan (October/November 1985) intensified so quickly that the offshore oil and gas industry was
                   unable to evacuate personnel on many rigs and platforms. As a result, a massive rescue of more than 140
                   people was performed by the U.S. Coast Guard. When the legs collapsed on the Penrod 61 drilling rig offshore
                   Louisiana, 43 people evacuated into escape capsules; however, one capsule swamped, which resulted in the
                   death of one crewman. By October 31, Hurricane Juan had come within 97 kin of New Orleans. As a result
                   of this storm, seven lives were lost, 50,000 homes were flooded, and there was an estimated $1 billion loss. On
                   November 1, tropical storm Juan left Louisiana and slowly drifted toward Alabama. It was the most destructive
                   hurricane of all as far as coastal erosion and landloss are concerned. Beaches along the entire Louisiana coast
                   eroded 6-30 in as a result of long-lasting, high tidal surges and storm waves. Channelswere widened and
                   several new inlets were created along the barrier islands, which were devegetated in some areas (Louisiana
                   Geological Survey, 1986). Hurricane Juan also adversely affected the Louisiana shrimp iridustry. It hit the
                   Louisiana coast at historically the most productive time of the year for shrimping, but boats stayed at port
                   because of rough seas. Considerable debris and detritus were deposited on the shrimping grounds, resulting
                   in losses to fishing gear and fishing time. The storm dispersed the population of shrimp, caused premature
                   immigration, resulted in some shrimp mortalities, and resulted in a decrease in shrimp landings (Chatry, 1986).
                   3. Air Quality

                       This section contains a description of air quality in the coastal areas of the Gulf of Mexico. One of the
                   mandates of the Clean Air Act was the establishment of National Ambient Air Quality Standards (NAAQS).
                   The Act established two standards, the primary standard to protect public health and a secondary standard to
                   protect public welfare. The National Ambient Air Quality Standards (40 CFR 50.4 to 50.11, 1990) are shown
                   in Table 111-2. The Clean Air Act amendments of 1990 established a classification scheme: based on degrees
                   of nonattainment for areas with air quality problems. These designations impose time: tables and other
                   requirements for reaching the attainment status, which depends on the degree of nonattah,,iment.
                       Pollutant measurements are collected from monitoring stations located at sites selected by State, Federal,
                   and/or private organizations. These measurements of pollutant concentration are processed using methods
                   described in 40 CFR 50 to calculate the annual number of expected exceedances of the national standards.
                   After the expected number of exceedances is calculated and compared with NAAQS, an area's air quality is
                   classified. Although the five states bordering the Gulf have adopted the standards established by the Clean
                   Air Act, Florida has modified the standards for total suspended particulates (TSP) and sulphur dioxide (SO2).
                   On occasion, the comparisons use stricter State-adopted standards. The USEPA classification for air quality
                   is as follows:











                                                                    Table 111-2


                                     National Ambient Air Quality Standards for the Five Gulf of Mexico
                                                 States, with More Restrictive Standards Shown
                                                             for the State of FloridaO



                                                                       Primary                  Secondary                  Florida
                      Pollutant               Timeframe                Standards                Standards                  Standards


                       PM 10                     annual                50 /jg/M3.               50 Lg/M3                   50 Lg/M3
                     particulate          (arithmetic meanc)           150 Ag/M3                150 pg/M3                  150 jLg/M3
                   Sulphur oxides                annual                80 tLg/M3                150 Lg/M3                  6O.Ug/m   3
                                          (arithmetic meanc)           (0.03 ppm)l              (0.02 ppm)                 (0.02 ppm)
                                                 24-hour               365 /IgIM3               260 Lg/M3                  260 Lg/M3
                                                                       (0.14 ppm)               (0-1 ppm)                  (0-1 ppm)
                                                 3-hourb                                        1,300,Ug/M3                1,300 Lg/M3
                                                                                                                           (0.5 ppm)

                 Carbon monoxide                 8-hourb               10 Mg/M3                 (same as                   (same as
                                                                       (9 ppm)                  primary)                   primary)
                                                 1-hourb               40 Mg/M3                 (same as                   (same as
                                                                       (35 ppm)                 primary)                   primary)

                  Nitrogen dioxide               annual                1W gg/M3                 (same as                   (same as
                                          (arithmetic mean)            (0.05 ppm)               primary)                   primary)

                   Photochemical           maximum daiV                235 @Lg/M3               (same as                   0.12 ppM3
                      o3ddantSe                  value                 (0.12 ppm)               primary)


                OThe air quality standards and a description of the Federal Reference Methods (FRM) can be found in 40 CFR
                 50 on July 1, 1990.
                bNot to be exceeded more than once a year.
                OArithmetic mean is sum of the data collected during the given period divided by the number of observations
                 in the same period.
                dParts per million.
                eThe FRM measures 03 (ozone).

                Note: Mg/M3       milligrams per cubic meter = l'WO Lg/M-3.
                        ,Lg/M3    micrograms per cubic meter.

                Source: 40 CFR 50, 1990, and Florida Dept of Environmental Regulation, 1987.











                  111-12


                                    Classification                               Definition


                                    Attainment                                   Meets or is less than standard
                                    Nonattainment                                Exceeds Standards
                                    Unclassified                                 No data exist to classify an area

                       Unclassified areas may either be nonattainment or attainment, but cannot be classified due to the lack of
                  air quality data in these areas. Figure III-1 presents the air quality status in the Gulf Coast as of July 1990 (40
                  CFR 81.301-319). (Notice that Figure III-1 includes a second layer of counties or parishes.) All air quality
                  nonattainment areas reported in Figure 111-1 include suspended particulate matter and ozone problems. The
                  following Texas coastal counties are classified as nonattainment for ozone: Brazoria, Galveston, Victoria,
                  Harris, Jefferson, and Orange. Chambers County, Texas, is being reclassified by USEPA ito nonattainment
                  According to the Federal Register notice of April 22, 1991, USEPA has notified the Governor of Texas that
                  theSO2 designation of Harris and Jefferson Counties should be revised. Cameron and Nueces Counties are
                  nonattainment for suspended particulate matter. Ile following Louisiana parishes are nonattainment
                  Calcasieu, Jefferson Davis, Lafayette, St Mary, Ascension, St James, St Charles, Lafourche, Jefferson, Orleans,
                  and St. Bernard. The State is taking steps to reclassify the parishes of Orleans, St Bernard, Jefferson, and St.
                  Charles.
                      Pollutant levels in some coastal areas of Texas are reported in the Air Monitoring Report, 1988 (Texas Air
                  Control Board, 1989). The pollutants monitored were nitrogen dioxide (NO2
                                                                                                  .), carbon monoxide (CO), sulphur
                  dioxide (SO2), particulate matter (TSP), and ozone (03). The Beaumont-Port Arthur area reported annual
                  average N02 concentrations of 13.2 jugm-@ This value is below the national standard of 100 ggm-31 but it
                  cannot be used for regulatory purposes because the sample is not adequate. Concentrations of CO in the
                  Beaumont-Port Arthur area had an 8-hr average of 3,435 /Lgm-3. which is well below the national standard of
                  10,000jugm-@ Most stations near coastal areas were below the national standard for CO. Sulphur dioxide
                  concentrations in the Beaumont-Port Arthur area had a highest 24-hr average of 107.7 Ugm-3-, Corpus Christi
                  reported a highest 24-hour average of 78.5 pgm-@ Both values are below the 24-hour average national standard
                  of 365 Agm-@ Particulate matter (PM,o) concentration in the Houston-Galveston-Brazoria area reported a
                  highest 24-hr average of 50 ggin   -3 most of the year; this value is below the national standard of 150 ggm-@
                  Data for South Texas had highest 24-hr averages between 60 and 100jagm-3; these averages are still below the
                  standard. Ozone measurements are more comprehensive and continuous. Concentrations in the Beaumont-
                  Port Arthur and Brazoria areas reported 1-hr average monthly maximum values that exceed the national
                  standard of 235 Agm-3; three times in 1988. Houston is above the standard most of the year. Corpus Christi
                  reports values near 200 Pgm    -3 most of the year, making this a border case area.
                      Measurements of pollutant concentrations in Louisiana are presented in the Ambient Air Quality Data
                  Annual Repor4 1989 (Louisiana Dept. of Environmental Quality, 1989). The N02 measurements in New
                  Orleans show that, during the period of 1985-1989, the 1-hr yearly maximum values varied between 161.8 and
                  250.2jugm-3, with the annual 1-hr mean varying between 41.3 and 48.9jugm-@ This information shows that
                  during the last five years the N02 standard has not been exceeded in New Orleans. Between 1985 and 1989
                  the CO concentrations in New Orleans show that 1-hr yearly maximum values varied between 13,627.9 and
                  18,208.7 jAgm -31while the annual mean varied between 1,257.7 and 2,404.9 jAgm-@ At other locations in New
                  Orleans, the concentrations were about 40 percent less than the values presented above. These values are
                  about 50 percent below the national standard. Concentrations of S02 are reported in two coastal areas. The
                  Meraux station, near the Mississippi River, showed an annual mean of 7.9 ggm-3 in 1989. Westlake, near the
                  Texas-Louisiana border, showed annual mean values between 5.2 and 13.1 ggm-@ Both stations were below
                  the annual average national standard of 80 jLgm-@ Particulate matter (PMo) was also reported at two stations
                  of interest. New Orleans reported annual mean concentrations of 31-37,ugm          -3 . which were below the annual
                  50jugm-@ In 1989, Lake Charles, near the Texas-Louisiana border, showed an annual mean concentration of
                  28 Agm-3 'which was still below the national standard. It is interesting that even maximum readings were below
                  the national standards. Ozone measurements for Louisiana are discussed in Section IV.D.l.a.(4).














                                                                                                   '41                  LOUISIANA








                                                                        FoRr




                                                                                                                                                              arm

                                                  )ICTO           WTAG*1A
                                          GOMD


                                 OAK
                                       +
                                      So PAM&                                                                           CENTRAL PLANNING AREA
                             vi6

                                         +  +


                          BROO                                                                                                                 [7] ATTAINMENT
                                                                                                                                                       TSP NON-ATTAINME
                                                                                                                                                       OZONE NON-ATTAIN
                                   wxwy
                                                                                                                                               RZ TSP AND OZONE NO



                          Figure 111- 1. Status of Air Quality in the Western and Central Planning Areas of the Gulf of Mexico.











                111-14

                     Measurements of three air pollutants (PM10, SO2, and 03) during 1990 and the first quarter of 1991 in
                Mobile County, Alabama, were secure. The sulphur dioxide monthly means varied from 13.1 to 33.9 pgm-@
                The highest 24-hr average concentration in the data never reached 105 ggin   -3 and the annual average was 20.5
                ggm-@ B@th statistics are below the national standard of sulphur dioxide. The PM10 measurements in Mobile
                          I
                County during the same time interval showed a highest 24-hr average concentration of 64 ggm-@ However,
                the number of observations in a given year was very low and varied from 1 to 61 daily observations. Hourly
                ozone measurements show that the mean monthly concentration varied from 15 to 70,ugm-@ The maximum
                1-hr concentration during 1990 was 246 ggm-3- this occurred in August All other measurements were below
                the nation' al standard. The data also show th'at the highest ozone concentrations tend to occur during the
                summer, aecrease during fall and whiter and reach a minimurn in April.
                     Ambient air quality is a function of size, distribution, activities of the State's population, industrial
                developm6nt, and emissions from sources such as internal combustion, solid-waste incineration, and chemical
                processing. Climatic conditions modify air quality by dispersing, distributing, or sometimes, unfortunately,
                concentrating emitted pollutants. Assessments of air quality depend on emissions and dispersion rates,
                distances from sources, and local meteorology. Because of the changing nature of these factors, air quality is
                not a steady quantity.
                     For a more complete description of the meteorological and climatic conditions that affect air quality, see
                Section III.A.2.

                4. Physical Oceanography
                     The Gulf of Mexico is a semi-enclosed, subtropical sea with an area of approximately 1.6 million km@ The
                main physiographic regions of the Gulf basin are the continental shelf (including the Campeche, Mexican, and
                U.S. shelves), continental slopes and associated canyons, abyssal plains, and the Yucatan and Florida Straits.
                The continental shelf width along the U.S. coastline is about 350 kni offshore West Florida; 16 km off the
                Mississippi River; and 156 kin off Galveston, Texas, decreasing to 88 km off Port Isabel near the Mexican
                border. The depth of the central abyss ranges to 4,000 m. The water volume of the Gulf, assuming a 2-km
                mean depth, is 2 million cubic kilometers; the shelf's volume, assuming a mean water depth of 50 m, is 25,000
                cubic kilometers. The Gulf is unique among the world's mediterranean seas, having two entrances: the
                Yucatan Strait and the Straits of Florida. Both straits restrain communication from the deep Atlantic waters
                because of the limited sill depths-1,600 ni in the Yucatan Strait and about 1,000 in in the Straits of Florida.
                A portion of the Gulf Stream system, the parent Loop Current, whose presence and influence are described
                below, is present in the Gulf. Along the 24,800-km Gulf coastline, 21 major estuaries are found on the U.S.
                coast The amount of freshwater input to the Gulf basin from precipitation and a number of rivers--dominated
                by the Mississippi and Atchafalaya Rivers--is enough to influence the hydrography of most of its northern
                shelves. However, the basin's freshwater budget shows a net deficit due to the high rate of evaporation.
                     Sea-surface temperatures in the Gulf, as shown in Figures 9A and 9B of Visual No. 7 for the EIS for Sales
                131, 135, and 137, range from nearly isothermal (29-300C) in August to a sharp horizontal gradient in January,
                ranging from 250C in the Loop core to values of 14-151C along the shallow northern coastal estuaries. August
                temperatures at 150 m show a warm Loop Current and an anticyclonic feature in the Western Gulf (both about
                18-19'C) grading into surrounding waters of 15-160C along the slope. The entire pattern is maintained during
                winter, but warmer by about 1*C. At 1,000 m, the temperature remains close to 50C year-round.
                     Surface salinities along the northern Gulf display seasonal variations because of the seasonality of the
                freshwater input During months of low freshwater input, deep Gulf water penetrates into the shelf, and
                salinities near the coastline range between 29 and 32 parts per thousand (ppt). High, freshwater-input
                conditions (spring-summer months) are characterized by strong horizontal gradients and inner-shelf salinity
                values of less than 20 ppt (Wallace, 1980; Cochrane and Kelly, 1986).
                     The vertical distribution of temperature, salinity, oxygen, and phosphate over six subareas of the Gulf are
                presented in Figure 8 of Visual No. 7 for the EIS for Sales 131, 135, and 137.             Also shown are the
                characteristic five major watermasses identified in the Gulf, down to about 1,000 m. This profile arrangement
                illustrates the influence of the Atlantic Ocean in the Gulf hydrography and the changes in water characteristics











                                                                                                                                   111-15

                brought about by the local climatology and hydrology. The main result is the creation of the Gulf watermass,
                which is confined to the surface layer through most of the Gulf basin. Intimately related with the vertical
                distribution of temperature is the thermocline, defined as the depth at which the temperature gradient is at
                maximum. During January, the thermocline depth is about 30-61 in in the Eastern Gulf and 91-107 in in the
                Central and Western Gulf. In May, the thermocline depth is about 46 in throughoutthe entire Gulf (Robinson,
                1973). This depth is important because it demarcates the bottom of the mixed layer and acts as a barrier to
                the vertical transfer of materials and momentum.
                    Sharp discontinuities of temperature and/or salinity at the sea surface, such as the Loop Current front or
                fronts associated with eddies or river plumes, are dynamic features that may act to concentrate buoyant
                material such as spilled off, detritus, or plankton. These materials are not advected by the front's translatory
                movement, such as Loop current incursion or the slow westward drift of eddies. The motion consists mainly
                of lateral movement along the front instead of motion across the front. In addition to open ocean fronts, a
                coastal front, which separates turbid, lower salinity water from the open-shelf regime, is probably a permanent
                feature of the Gulf shelf. Figure 7 of Visual No. 7 for the EIS for Sales 131, 135, and 137 indicates that the
                front lies about 30-50 kin offshore. It is not known how strongly this front might affect buoyant material
                transport.
                    The Loop Current, a highly variable current feature, enters the Gulf through the Yucatan Strait and exits
                through the Straits of Florida (as the Gulf Stream) after tracing an arc that may intrude as far north as the
                Mississippi-Alabama shelf. The Loop consists of ascending and descending 30-km-wide bands of rapidly moving
                water enclosing a relatively quiescent inner region, and the entire feature may be clearly seen in hydrographic
                sections down to about 1,000 in. Below that level, there is evidence of a countercurrent. The volumetric flux
                of the Loop has been estimated at 30 million m3s-1. Velocities up to 300 cms-1 have been measured, but a
                range of 100-200 cms-1 is probably representative. This volume flow is enough to replace the water volume
                of the Gulf shelf in about 10 days.
                    The "location" of the Loop Current is definable only in statistical terms, due to its great variability. Figure
                5A of Visual No. 7 for the EIS for Sales 131, 135, and 137 shows the relative existence probabilities for Loop
                Current water throughout the Eastern Gulf in March, the month of apparent greatest intrusion. Values range
                from a 100-percent core location at 251N, down to small probabilities (10%) near midshelf. Figure 5B of
                Visual No. 7 for the EIS for Sales 131, 135, and 137 shows the results of a "wave-staff" analysis, where observed
                Loop front locations along selected meridional lines are analyzed for central tendency, range, and dispersion.
                An average northern intrusion is indicated to 26.60N, within a wide envelope. Both analyses exclude the period
                June-October due to limitations on satellite data.
                    The process responsible for the first-order variability of the Loop is the shedding of anticyclonic,
                warm-water eddies, which may occur when the current is greatly extended. The usual eddies are large, resulting
                in significant dimensional adjustment by the Loop. This is clearly seen in the data in Figure 5C of Visual No.
                7 for the EIS for Sales 131, 135, and 137. Processes responsible for smaller, or second-order, variability of the
                Loop include persistent wind forcing, shelf-edge interactions along the Yucatan Shelf and the West Florida
                Shelf, and waves along the Loop front associated with the eddy cycle. These instabilities may grow into large
                intrusions of warm Loop water onto the adjacent shelf and/or entrain colder shelf water into the Loop itself,
                as seen in Figure 5D of Visual No. 7 for the EIS for Sales 131, 135, and 137. Collectively, these processes set
                up a zone of Loop Current fluctuation extending over the outer shelf, the slope, and the abyssal areas off
                Mississippi, Alabama, and Florida (MAFLA).
                    The eddy-shedding cycle has earlier been the subject of much field work and currently of numerical
                modeling. Based on these data, Figures 1A, 1B, and 1C of Visual No. 7 for the EIS for Sales 131, 135, and
                137 have been prepared to illustrate the overall cycle, including the subsequent behavior of the eddies. Recent
                analysis of frontal-positions data indicates that the eddy-shedding period varies between 6.5 and 9.5 months with
                an average of 7.5 months (Hamilton et al., 1989). Major Loop Current eddies have diameters on the order
                of 300400 kin and may clearly be seen in hydrographic data to a depth of about 1,000 in. Swirl velocities
                within the eddies have been reported from 50-200 cms-1. As seen in Figures 4A, 4B, and 4C of Visual No. 7
                for the EIS for Sales 131, 135, and 137, they move into the Western Gulf along various paths to a region
                between 251-28ON and 93'-961W. The eddies move at speeds ranging from 2-5 kind-', decreasing in size as they











                 111-16

                 mix with resident waters. The life of an individual eddy to its eventual assimilation by regional circulation
                 patterns in the Western Gulf is about I year.
                     Eddy-shedding from the Loop Current is the principal mechanism coupling the circulation patterns of the
                 eastern and western parts of the basin. The heat and salt budgets of the Gulf are dependent on this
                 importation, balanced by seasonal cooling and river input, and probably also by internal, deeper currents that
                 are poorly understood. These currents may be evident in intriguing hints of abyssal bottom scour and the
                 reversed currents beneath the Loop itself. The eddies are frequently observed to affect local current patterns
                 along the Louisiana/Texas slope, hydrographic properties, and possibly the biota of fixed platforms or hard
                 bottoms. There is some evidence that these large reservoirs of warm water play some role in strengthening
                 tropical cyclones when their paths coincide.
                     Smaller anticyclonic eddies have been observed to be generated by the Loop Current, although it is not
                 known if the process is merely a scaled-down version of the above cycle. They have diameters on the order
                 of 100 km, but the few data available indicate a shallow hydrographic signature on the order of 200 m. Their
                 observed movements indicate a tendency to translate westward along the Louisiana/Texasslope. Some are
                 included in the analysis presented in Figure 4B of Visual No. 7 for the EIS for Sales 131, 135, and 137. Similar
                 in size, cyclonic eddies are observed in the Eastern Gulf, are associated with the eddy-sheddihg cycle, and are
                 along the Louisiana/Texas slope. Their genesis and role in the overall Gulf circulation are not well studied.
                 A major cyclonic eddy seems to be resident in the southwestern Gulf, based on older data synthesis; however,
                 some recent evidence points toward a more complex, less homogeneous structure.
                     Three studies have attempted to quantify the open Gulf circulation. Figure 2A of VisualNo. 7 for the EIS
                 for Sales 131, 135, and 137 displays the results of calculating the mean surface topography from all expendable
                 bathythermograph and Nansen cast data from the National Oceanographic Data Center (NODC), carefully
                 edited. Figure 2B of Visual No. 7 for the EIS for Sales 131, 135, and 137 displays the mean surface elevation
                 from a 3-year simulation with the same model as Figures 1A, 113, and 1C of Visual No. 7 for the EIS for Sales
                 131, 135, and 137, including wind forcing. All figures generally agree on the Loop Current region and an
                 anticyclonic high in the Western Gulf, with some minor disagreement on details. Figure 2C of Visual No. 7
                 for the EIS for Sales 131, 135, and 137 translates the mean surface elevations of Figure 2B of' Visual No. 7 for
                 the EIS for Sales 131, 135, and 137 into surface-current vectors, illustrating the interpretation of topographic
                 contours. Although the mean surface topography may be considered to represent the mean surface circulation
                 of the Gulf, it has little utility for the reasons discussed below.
                     The regions of greatest variability in surface-contour analyses represent the regions of greatest current
                 variability in the Gulf. These are areas where the use of long-term average currents could lead to misleading
                 results in calculations of oil-spill trajectories. The errors result from the fact that mean. speeds are not
                 representative of the prevailing circulation. The studies depicted in Figures 2A and 2B of Visual No. 7 for the
                 EIS for Sales 131, 135, and 137 have been analyzed to yield variability surfaces. Figure 3A ofVisual No. 7 for
                 the EIS for Sales 131, 135, and 137 shows the variability from the hydrographic study, emphasizing the zone
                 of eddy detachment from the Loop centered about 26.5'N and 88.51W. Figure 3B of Visual No. 7 for the EIS
                 for Sales 131, 135, and 137 shows the variability from the modeling study, emphasizing a broad eddy
                 detachment zone, a zone centered about 23IN and 94.5'W where many eddies go initially, and the zone
                 identified in Figure 2B of Visual No. 7 for the EIS for Sales 131, 135, and 137. Figure 3C of Visual No. 7 for
                 the EIS for Sales 131, 135, and 137 displays the results of direct measurements of surface; variability from
                 satellite altimeters.
                     Aside from the wind-driven surface layer, current regimes on the outer shelf and slope are the result of
                 balance between the influence of open Gulf circulation features, such as the Loop and eddies, and the shelf
                 circulation proper, which is dominated by long-term wind forcing. A western boundary current, driven both
                 by prevailing winds and the semipermanent anticyclonic eddy, occurs offshore northern Mexico and South
                 Texas. A strong east-northeasterly current along the remaining Texas and Louisiana slope has been expla mied
                 partly by the effects of the semipermanent, anticyclonic eddy and a partner cyclonic eddy ("modon pair") and
                 partly by the mass-balance requirements of eddy movement. Within the Loop Current fluctuation zone,
                 offshore the MAFLA states, the intrusion of the Loop front or the presence of minor detached eddies sets up
                 short-term strong currents, but no permanent current has been identified other than a weak statistical residual.
                 When the Loop Current impinges onto the Florida slope and shelf, it has been observed that the current











                                                                                                                                111-17

              structure acts to upwell nutrient-rich water from deeper zones, a mechanism that may also take place as eddies
              move along the Louisiana/Texas slope, accounting for the increased productivity recognized in these areas.
              West of approximately Cameron, Louisiana (931W), current measurements clearly show a strong response of
              coastal current to the winds, setting up a large-scale, anticyclonic gyre. The inshore limb of the gyre is the
              westward or southwestward (downcoast) component that prevails along much of the coast, except in
              July-August . Because the coast is concave, the shoreward prevailing wind results in a convergence of coastal
              currents at a location where the winds are normal to the shore or at the downcoast extent of the gyre. A
              prevailing countercurrent toward the northeast along the shelf edge constitutes the outer limb of the gyre. The
              convergence at the southwestern end of the gyre migrates seasonally with the direction of the prevailing wind,
              ranging from a point south of the Rio Grande in the fall to the Cameron area by July. The gyre is normally
              absent in July but reappears in August-September when a downcoast wind component develops (Cochrane and
              Kelly, 1986).
                   The Mississippi/Alabama shelf circulation is controlled by the Loop Current, winds, tides, and freshwater
              input During intrusions of the Loop into the shelf, the Loop will completely dominate the shelf circulation;
              when located offshore, the Loop may drive a counter-clockwise circulation. Tidal currents of 15 cms-' have
              been observed in this area (Vittor and Associates, Inc., 1985). The general circulation is a two-season event.
              During winter, the water column is homogeneous and surface circulation is mainly alongshore and westward
              at mean speeds of 4-7 cms-1. The cross-shelf component is smaller and directed onshore. During
                                                                                                                                     1
              spring-summer conditions, the surface flow is mostly eastward with mean speeds in the range of 2-7 cms- .
              However, during periods of sustained winds from the west, northwest, north, and northeast, near-bottom speeds
              average 20 cms-1 in water depths of 20 m. With sustained winds from the southeast, south, and southwest, the
              near-bottom average speed increases to 26 cms-1. Under winds with easterly components, the water tends to
              flow shoreward and accumulate against the shoreline, creating a pressure gradient that drives bottom water
              alongshore in the direction of the winds (Vittor and Associates, Inc., 1985).
                   The West Florida shelf circulation is dominated by tides, winds, eddy-like perturbations, and the Loop
              Current. Tidal currents are slightly dominated by diurnal components with speeds of about 5 cms-1 at spring
              tides. The wind-driven flow is mostly alongshore and parallel to the isobaths at water depths less than 30 m.
              The mean flow is directed southward with mean speeds ranging from 0.2-7 cms-1 in the surface layer. Near
              the shelf edge the flow is onshore from surface to mid-depth and offshore below. The mean onshore speeds
              are 0.4-3 cms-1, and the general offshore speeds are less than 1 cms-1. The Loop influence is by direct or
              indirect forcing by the intrusions and meanders. This influence is felt most strongly along the shelf break and
              slopes. The actual circulation is composed of several components of different frequencies of which the 10-14
              days component contains a large fraction of the variance. Wind-driven events induce horizontal particle
              excursions, which are proportional to the period of the event; thus, longer periods cause longer particle
              excursions (SAIC, 1986).
                   Longshore currents, consisting of tidal, wind-driven, and density-gradient components, predominate over
              across-shelf components within a narrow band close to the coast (on the order of 10-20 km, referred to as the
              coastal boundary layer). Typical maximum tidal currents within this band would be about 15 cms-1. These
              currents will cause a particle displacing, known as the tidal excursion, at 2-3 km. Currents, driven by
              synoptic-scale winds, range up to 25-50 cms-1 for nonextreme conditions,with 10- to 100-km excursions expected
              for a typical 5-day "wind event." LA)ngshore currents due to winter northers, tropical storms, and hurricanes
              may range up to hundreds of cms-1, depending on local topography, fetch, and duration. Should an oil spill
              occur, deviations from results predicted by open-ocean models could happen at coastal fronts, where
              concentration and lateral translation could occur, and within the longshore-current zone, where significant
              transport away from the "expected" point of contact could occur, as determined by local tidal phase and
              predominant winds.
                   Studies of surface drifters are useful and illustrative in the study of oil movement because, hopefully,
              surface slicks will respond to currents in a similar way. A summary of drifter studies across the Gulf (Parker
              et al., 1979) indicated that the Texas coastline and the southern and eastern Florida coastlines receive the most
              landings. Other coastlines along the Gulf received very small numbers of landings. A study along the Florida
              west coast (Williams et al., 1977) found that during fall and winter most reports were from south and eastern
              Florida. During the spring and summer, the lower west, south, and eastern Florida coastlines received similar











                  111-18

                  landings. Strangely, during summer and fall, the Louisiana and Texas coastlines received ssizable fractions of
                  the landings. However, these results contain some bias because populated or frequently visited areas would
                  show more landings than desolated areas.
                       Figures 6A, 613, 6C, and 6D of Visual No. 7 for the EIS for Sales 131, 135, and 137 show the seasonal
                  mean winds from a multiyear analysis. An annual cycle of wind direction is indicated: winter winds from the
                  east-northeast; spring winds from the southeast; summer winds from the southeast and south; and fall winds
                  shifting back to the east-northeast. The distribution of wind speeds is shown in Figure 6G of Visual No. 7 for
                  the EIS for Sales 131, 135, and 137. Western summer winds have a mode at 4-6 ms-1, compared to 2-4 ms-1
                  in the Eastern Gulf. Winter winds are stronger in both regions, principally in the 8-10 ms-I interval, which may
                  be due to cold fronts transiting the southeastern United States every 3-10 days in the fall and winter. Not
                  reflected in the wind climatology are the much stronger winds associated with tropical cyclones that frequently
                  move through the greater Caribbean area. The classes of cyclones, and their defining minimum wind speeds,
                  are as follows: tropical depression (up to 16 ms-1); tropical storm (17-31 ms-1); and hurricane (32 ms-i or
                  more). Figure 6E of Visual No. 7 for the EIS for Sales 131, 135, and 137 gives the probabilities that at least
                  one cyclone in the storm or hurricane category will occur in a defined zone in a given year.
                       A summary of significant wave-height measurements, based on a multiyear analysis, is presented in Figure
                  6G of Visual No. 7 for the EIS for Sales 131, 135, and 137. Western summer waves tend to be smaller than
                  those in the Eastern Gulf; waves in both regions intensify in winter, with the Western Gulf showing a clear
                  mode at 2-3 in. Not reflected in these results are the much larger waves associated with hurricanes. Figure
                  6F   'of Visual No. 7 for the EIS for Sales 131, 135, and 137 displays the hindcast significant wave heights for
                  several hurricanes since the onset of offshore development, indicating a range of about 6-12 in for open shelf
                  waves. Also displayed are the expected 100-year maximum wave heights, which could range to 21+ in.

                  5. Chemical Oceanography

                  Regional Oveniew

                       The discussion that follows heavily emphasizes hydrography and the productivity aspects of classical
                  chemical oceanography. Process-oriented material is not presented, as no unique mechanisms are known to
                  prevail in the Gulf of Mexico.
                       The Gulf enjoys the benefit of having been the subject of a number of regional- or basin-scale studies
                  emphasizing chemistry of the water column, and of several valuable reviews. The material synthesized below
                  is derived from an extensive library of sources, someof which are identified by specific information.
                       Due to the ambience of the medium, space scales far greater than those considered rellevant in biological
                  considerations apply to chemical oceanographic assessment Watermass characterizations are generally
                  applicable at scales on the order of 1,000 km, while processes related to mesoscale-circulation patterns, such
                  as primary production, probably should be described in terms of 100-km scales. For these reasons, the
                  following description is organized to proceed from greater to lesser scales as the emphasis shifts from nearly
                  conservative basinwide characteristics to regionally variable, inshore/offshore parameters.
                       The Gulf of Mexico is a semienclosed system with oceanic input through the Yucatan Channel and
                  principal outflow through the Straits of Florida. Runoff from approximately two-thirdsof the area of the
                  United States and more than one-half the area of Mexico empties into the Gulf. This large; amount of runoff,
                  with its nonoceanic composition, is mixed into the surface water of the Western Gulf and makes the chemistry
                  of parts of this system quite different from that of the open ocean. For a discussion of Gulf circulation
                  patterns, see Section III.A.4.

                  Mired-Layer Hydrography

                       Salinity: The mixed layer, extending down to a depth of approximately 100-150 in, is characterized by
                  salinities between 36.4 ppt and 36.5 ppt in the open Gulf. Salinity values in shelf and estuarine regions may
                  vary widely from this range due to the opposing effects of river input and enhanced evaporation. Alternating











                                                                                                                                111-19

                floods and droughts may cause salinity changes from nearly fresh to 100 ppt, three times that of normal
                seawater. These variations can lead to mass mortality of marine organisms (Caruthers, 1972; Corcoran, 1973;
                Nowlin, 1972).
                    Temperature: In the Eastern Gulf, maximum surface temperatures range from 27'C in late winter to about
                30'C in the summer. A range of 22-29PC is observed in the Western Gulf-, the difference reflects the steadying
                influence of the Loop Current (Corcoran, 1973; Dames and Moore, 1979; Flint and Raba", 1980; Ichiye et
                al., 1973; Nowlin, 1972; SUSIO, 1977 and 1978; Williams, 1954; Woodward-Clyde Consultants, 1982). The
                lowest values encountered may range as low as approximately 101C in the Louisiana-Mississippi shelf region
                at times of extraordinary snowmelt in the tipper Mississippi valley.
                    Oxygen: Dissolved oxygen values in the mixed layer average about 4.6 ml/L, with certain seasonal variation,
                particularly a slight lowering during the summer months. Oxygen values generally decrease to about 3.5 ml/L,
                with depth through the mixed layer (Caruthers, 1972; Corcoran, 1973; Nowlin, 1972; Williams, 1954).

                    Watermass Hydrography

                    Eight specific watermasses are recognized to occur in the Gulf (Table 111-3).

                    Exotic Waters

                    Hypersaline Basins: Two basins containing hypersaline waters have been identified. Salinities as high as
                196 ppt at a small pool on the East Flower Garden topographic high and 250 ppt in the Orca Basin have been
                measured (Rezak et al., 1985; Addy and Behrens, 1980). Unique regimes may be present at these sites due
                to the partial absence of oxygenated chemical species.
                    Midshelf Freshwater Vents: At a number of sites on the southwest Florida shelf, submarine springs are
                present, found in association with extensive karst topography. Little is known about the chemical regime of
                the associated biota within these features.


                Micronutrients


                    Nutrient Cycling. The principal micronutrients about which generalizations can be drawn, based on the
                limited data available, are phosphate, nitrate, and silicate. Phytoplankton consume phosphorus and nitrogen,
                principally via their ionic species, in an approximate ratio of 1:16 for growth. Silicon is consumed for
                production of skeletal structures, particularly by diatoms, which are present in enormous numbers in Gulf
                waters. Mineralization of dead plankters returns the nutrients to the water column, although typically at a
                greater depth than that of initial assimilation, due to sinking.
                    Mixed-Layer-Distribution Patterns: Phosphates range from 0 to 0.25 parts per million (ppm), averaging
                0.021 ppm. Shelf values do not differ significantly from open Gulf values. Integrated Eastern Gulf values are
                somewhat lower than Central and Western Gulf values. Silicates range predominantly from 0.048 to 1.9 ppm.
                Open Gulf values tend to be lower than shelf values. Integrated Eastern Gulf values are again somewhat lower
                than Western Gulf values. Nitrates range from 0.0031 to 0.14 ppm, averaging 0.014 ppm. Open Gulf values
                are slightly higher than shelf values. There is no clear pattern in depth-integrated values between regions
                (Corcoran, 1973; Dames and Moore, 1979; Flint and Rabal", 1980; Ichiye et al., 1973; Nowlin, 1972; SUSIO,
                1977 and 1978; Williams, 1954; Woodward-Clyde Consultants, 1982).
                    Vertical Disvibution: Vertical distributions of nutrients show five general features related to both the
                identified watermasses and the biological activity: (a) low concentration in the mixed layer (to 100 or 200 m);
                (b) substantial increase from 200 in to 700 or 800 in; (c) maximum values at approximately 800-1,000 in; (d)
                small decreases in concentration below 1,000 m; and (e) homogeneous concentrations below about 1,500 m.
                At the maxima, phosphate concentrations range from 0.14 to 0.23 ppm, silicates from 1.9 to 2.3 ppm, and
                nitrates from 1.8 to 2.1 ppm (Corcoran, 1973; Dames and Moore, 1979; Flint and Rabalais, 1980; Ichiye et al.,
                1973; Nowlin, 1972; SUSIO, 1977 and 1978; Williams, 1954; Woodward-Clyde Consultants, 1982).











                    111-20








                                                                           Table 111-3


                                                     Water Mass Characteristics in the Gulf of Mexico



                                                                                                      Depth Range
                              Water Mass                  Extreme           Concentrations                 LMJ                    Location

                              Gulf Water                  Salinity           36.4-36.5 ppt                0-250                   Gullwide
                                                          maximum


                              Subtropical                 Salinity             less than                 100-300               Eastern Gull'
                              Underwater                  maximum               36.8 ppt
                              (SUW)

                              180 Sargasso                Oxygen              (small and                 200-400               Eastern Gulf*
                              Seawater                    maximum              variable)
                              18OSSW


                              Tropical Atlantic           Oxygen             2.5-2.9 m1/1                2504M                    Gulfwide
                              Central Water               minimum


                              Antarctic Inter-            Nitrate            29-35 gg-at/l               500-700                  Gulfwide
                              mediate Water               maximum


                              Antarctic Inter-            Phosphate         1.7-2.5,ug-at/l              600-800                  Gultwide
                              mediate Water               maximum


                              Antarctic Inter-            Salinity          34.88-34.89 ppt              700-"                    Gulfwide
                              mediate Water               maximum


                              Mixture of North            Silicate           24-28jug-at/1             1,000-1,100                Gullwide
                              Atlantic Deep Water         maximum
                              and Caribbean
                              Mid-Water


                              *SUW may occasionally be -found in the Western Gulf in eddies detached from the Loop Current.
                              There have also been indications of 180 SSW in detached eddies, but the evidence is slight.

                              Sources: Barnard and Froelich, 1981; Caruthers, 1972; Corcoran, 1973; El-Sayed, 1972; Iverson and
                                        Hopkins, 1981; Nowlin, 1972; SUSIO, 1977 and 1978; Williams, 1954; Woodward-Clyde
                                       'Consultants, 1982.











                                                                                                                                   111-21

                Particulate and Optical Parameters

                    Biological primary production in the Gulf is critically dependent on both chemical and physical factors.
                The driving photosynthetic mechanism is light-limited; and, due to attenuation processes in the water column,
                it is ineffective below an average depth of about 75 m, where incident light has been reduced to about I
                percent. The most highly variable component of total light-field attenuation in the water column is the
                scattering induced by suspended particles, both organic and inorganic. Particles also act as substrates for
                bacterial activity, transport loci for absorbed species, and act as physical irritants to sensitive biological species.
                Open Gulf waters have particulate loads ranging from about 0.1 to 0.2 ppm. Over 50 percent of the suspended
                particulate matter is organic in surface waters, decreasing to about one-third in deeper waters. The inorganic
                fraction is composed largely of clay minerals, reflecting the importance of the Mississippi River as a source
                (Hedges and Parker, 1976).
                    A common phenomenon in the Gulf, especially on the shelf, is the local presence of greatly elevated levels
                of suspended material, with values above 1 ppm. Typically, near-bottom layers of turbid water are encountered
                and are separated from overlying waters by sharp discontinuities. These "nepheloid" layers may be associated
                with resuspension by bottoms currents, internal waves, intense at-depth biological activity, or a complex
                combination of these factors. These features appear to occur naturally at nearly all locations on the shelf and
                upper slope environment, excepting the promontories of significant topographic highs.

                Primary Production

                    Productivity Measurements

                    Regional Distribution: Primary production, the conversion of mineralized nutrients to living phytoplankton
                tissue as measured by    C14 uptake, occurs predominantly at the low level of 0.25 mc/m3/hr or less throughout
                the Gulf. Higher levels, between 0.25 and 1.0 units, are found at northeastern and southern locations, with
                maximum values on the Yucatan shelf. In terms of depth-integrated values, western regions seem to be more
                productive than the eastern regions (Barnard and Froelich, 1981; EI-Sayed, 1972; Iverson and Hopkins, 1981;
                LaRock and Bittaker, 1973; Williams, 1954).
                    Depth Distribution: Higher productivity levels are sustained at subsurface levels rather than at the surface.
                Maximum    C14  assimilation generally occurs at depths corresponding to 50-25 percent of surface-light intensity
                (Barnard and Froelich, 1981; EI-Sayed, 1972; Iverson and Hopkins, 1981; LaRock and Bittaker, 1973; Williams,
                1954).
                    Seasonal Distribution: Unlike temperate or high-latitude waters where the amplitude of the seasonal
                variations in productivity is manifold, the amplitude in the Gulf is very much damped. The ratio of maximum
                (winter) to minimum (spring) integrated productivity is approximately 2:1 (Barnard and Froelich, 1981;
                EI-Sayed, 1972; Iverson and Hopkins, 1981; LaRock and Bittaker, 1973; Williams, 1954).

                Chlorophyll Measurements

                    Regional Dimibution: The distribution of chlorophyll closely parallels that of productivity. Most values
                range from 0.05 to 0.30 Mg/M3 (ppb), with highest values found off the Mexican coast. In terms of
                depth-integrated values, the region of the Loop Current seems to show higher values for chlorophyll than the
                Central and Western Gulf (Barnard and Froelich, 1981; El-Sayed, 1972; Iverson and Hopkins, 1981; LaRock
                and Bittaker, 1973; Williams, 1954).
                    Depth Distribution: Maximum chlorophyll concentrations occur very deep within the portion of the water
                column where the light exceeds I percent of surface insolation, the euphotic zone. In some cases, maxima are
                found below the euphotic zone, possibly reflecting sinking plankters. Secondary peaks of chlorophyll above
                the maximum may be associated with thermal gradients in the water column.
                    Seasonal Disvibution: Maximum (winter) depth-integrated values for chlorophyll exceed minimum (fall)
                values only by a factor of about 1.2 (Barnard and Froelich, 1981; EI-Sayed, 1972; Iverson and Hopkins, 1981;
                LaRock and Bittaker, 1973; Williams, 1954).











                 111-22


                 Total Production
                     Average depth-integrated primary productivity in the Gulf is about 0. 1 gc/m2/day, for an annual production
                 of 17 gc/1P/day. This value is about one-half the average for all the world's seas and one-half to one-fourth
                 the value for the western-central Atlantic. Annual total production for the Gulf is about 43 million metric tons
                 of carbon'(Bamard and Froelich, 1981; EI-Sayed, 1972; Iverson and Hopkins, 1981; LaRock and Bittaker, 1973;
                 Williams,, 1954). Assuming a carbon content of 50 percent in the biomass, a gross annual production of 86
                 million metric tons can be calculated.


                 Central Gulf of Mexico

                     Estuarine and Inner Shelf

                     Hydrography and Nutrient Chernimy: This area is strongly influenced by the presence of America's major
                 river, the Mississippi, as well as a host of other major drainage systems. A complex geography of sounds and
                 bays protected by barrier islands and extensive tidal marshes acts to delay mixing, resulting in extensive areas
                 of mesohaline (middle salinity) conditions. Turbidity is normally quite high, with suspended sediments up to
                 1-10 mg/L, primarily composed of clay minerals. The salinity gradients established in estuarine areas are
                 extremely important for the maintenance of finfish and shellfish production; thus, enormous fluctuations in
                 harvest may occur paralleling annual hydrology (Barrett et al., 1971; Christmas and Eleuterius, 1973; Gallaway,
                 1981; SUSIO, 1977 and 1978; Woodward-Clyde Consultants, 1982).
                     In general, Louisiana's estuaries and open nearshore waters are low in salinity and high in nutrient
                 concentrations as compared with other states bordering the northern Gulf. These characteristics are due
                 primarily to Louisiana's high rainfall and the large volume of river water that makes its way through rich
                 alluvial soils to the Gulf of Mexico. The major contributors of nutrients to the estuaries are the Mississippi
                 and Atchafalaya Rivers (Barrett et al., 1971; Christmas and Eleuterius, 1973; Gallaway, 1981; SUSIO, 1977 and
                 1978; Woodward-Clyde Consultants, 1982).
                     The Mississippi River input acts to create a lens of fresher, more turbid water, often curling to the west.
                 Hydrographic studies, suspended-sediment characteristics, and sensitive chemical analyses demonstrate its
                 influence as far west as South Texas. Of importance is the water-column stratifying effect of this fresh lens on
                 nearshore waters. It is frequently observed during summer months, particularly August, that hypoxic
                 bottom-water conditions exist on the central Louisiana shelf in zones that may extend over 50 km along
                 shore-normal transects. Mass mortality of organisms and characteristic chemical changes also occur. These
                 conditions have serious implications for the continued viability of the local fisheries and for monitoring
                 programs of any sort (Boesch and Rabalais, 1987).
                     Primary Production: As a probable consequence of the large fluvial input of nutrients, the Louisiana
                 nearshore shelf is considered one of the most productive areas of phytoplankton in the Gulf. Integrated
                 chlorophyll values are two times average Gulf values, and integrated production values range an order of
                 magnitude greater than the Gulf average (Barrett et al., 1971; Christmas and Eleuterius, 1973; Gallaway, 1981;
                 SUSIO, 1977 and 1978; Woodward-Clyde Consultants, 1982).

                 Outer Shelf and Slope

                     Hydrography and Nutrient Chemistry: Less is known about the central area than other zones. Observations
                 indicate that the effects of the Mississippi are felt here, although much reduced by distance. Hypoxic bottom
                 waters are not reported, although surface freshening occurs at times of maximal discharge. Upwelling of
                 cooler, nutrient-rich waters onto the shelf is known, but the mechanism is not fully understood since regional
                 circulation patterns remain unclear. The passage of detached, anticyclonic eddies toward the west may be
                 important in this regard. The water column is frequently observed to contain turbid layers associated with
                 interfaces between two or three distinct water layers. A Mississippian origin is suggested for these layers
                 (Gallaway, 1981; Southwest Research Institute, 1981).











                                                                                                                                111-23

                    Primary Production: No studies characterizing this specific region have been identified. It is believed that
                values for productivity and chlorophyll approach Gulf averages, but that circulation events, such as the transient
                effects of passing eddies, might play a role in enhancing these values (Gallaway, 1981; Southwest Research
                Institute, 1981).

                Western Gulf of Merico

                    Estuarine and Inner Shelf

                    Hydrography and Nutrient Chemistry: Nutrient concentrations are generally representative of open-Gulf
                surface waters, but continental runoff influences nearshore surface concentrations, especially in spring.
                Nutrients are reduced to extremely low values after spring and summer blooms but are replenished in the fall
                (Cafflouet et al., 1981; Flint and Raba", 1980; Gallaway, 1981).
                    The water column over the inner shelf is very nearly isothermal during the fall, winter, and spring months,
                showing a slight stratification only in summer. Temperatures characteristic of the mixed layer over the inner
                Texas shelf range from approximately 11-131C in late summer. Salinities range from open-Gulf surface values
                of about 36.4 to 20 ppt or less during the spring runoff or during heavy rainfall. A bottom nepheloid layer is
                nearly always observed (Caillouet et al., 1981; Flint and Rabalais, 1980; Gallaway, 1981).
                    Pfimary Production: Chlorophyll is highly correlated with salinity decreases in this area, indicating the
                influence of riverine input. The local input from Texas rivers is the major source of freshwater nutrients and
                turbidity in the region. These effects decrease with distance from shore. Most chlorophyll is found at the
                bottom of the water column, from the shore out to mid-shelf (Caillouet et al., 1981; Flint and Rabalais, 1980;
                Gallaway, 1981).

                Outer Shelf and Slope

                    Hydrography and Nutrient Chemistry: Beyond the nearshore region of heavy influence by Texas rivers, the
                effects of the Mississippi River are more obvious. Although salinity variations are seen to respond to
                Mississippian input, nutrients do not correspond as closely, due perhaps to some depletion during transit.
                Overall, the nutrient values are somewhat lower than inshore values. The intrusion of nutrient-rich,
                oxygen-poor water from apparent depths of 200-300 in is indicated in many cases, with effects seen all the way
                up to 70 in in depth. An area of major upwelling has been indicated along the shelf break (Flint and Rabalais,
                1980; Gallaway, 1981; McGrail et al., 1978).
                    Primary Production: Productivity on the outer shelf exhibits much less variability, which can be ascribed
                to riverine input. Chlorophyll values in this area average less than inshore areas, as expected, but an inverse
                relation with salinity is not found. Aperiodic upwelling events are probably of primary importance in regulating
                offshore production in this area (Flint and Rabalais, 1980; Gallaway, 1981; McGrail et al., 1978).

                Eastern Gulf of Mexico

                    Estuarine and Inner Shelf

                    Hydrography and Nutrient Chemistry: The major influence on this zone is atmospheric forcing combined
                with the seasonal input from fluvial sources. Pockets of high salinity (greater than 36.8 ppt) may be found on
                the bottom, possibly produced by enhanced evaporation during the summer. It is very rare for Loop Current
                waters to intrude landward of the 20-m contour, bringing nutrient-rich waters. In general, resident waters
                remain nutrient deficient with the exception of the immediate vicinity of estuaries. Oxygen values are at or
                near saturation, and profiles show little structure. Extraordinary blooms of pathogenic phytoplankton, known
                as "red tide," may occur on the mid- to inner-shelf. These outbreaks may be associated with rare Loop Current
                intrusions, nutrient flux from estuaries, or both (Corcoran, 1973; Dames and Moore, 1979; Ichiye et al., 1973;
                LaRock and Bittaker, 1973; SUSIO, 1977 and 1978; Woodward-Clyde Consultants, 1982).











                  111-24

                      Primary Production: Outside the estuaries, productivity values generally are low.

                  Outer Shelf and Slope

                      Hydrography and Nutrient Chemistry: The major influence in this zone is undoubtedly the pervasive
                  influence of the Loop Current. It is fairly well-established that the Current acts to pump nutrient-rich, deeper
                  waters up onto the shelf. This mechanism acts most demonstrably during the passage of froniAl eddy structures
                  and may be reinforced by wind-driven upwelling. Near-bottom increases in particle content are a usual
                  condition, but the explanation consists of a complex summation of occasional bottom-current effects and
                  enhanced productivity at depth. Watermasses present range from surface mixed-layer characteristics to
                  upwelled, subtropical underwater (SUW) characteristics (Corcoran, 1973; Dames and Moore, 1979; Ichiye et
                  al., 1973; LaRock and Bittaker, 1973; SUSIO, 1977 and 1978; Woodward-Clyde Consultants, 1982).
                      Pr@mary Anoduction: Both chlorophyll and productivity values at the surface are normally low in this area,
                  with the significant exception of patches of enhanced activity occurring within the upwelled parcels of colder
                  waters found in cyclonic circulation cells associated with Loop Current frontal eddies. Chlorophyll and
                  productivity values about an order of magnitude greater are probably the usual condition near the bottom of
                  the euphotic zone due to the often intruded, nutrient-rich Loop undercurrent waters (Corcoran, 1973; Dames
                  and Moore, 1979; Ichiye et al., 1973; LaRock and Bittaker, 1973; SUSIO, 1977 and 1978; Woodward-Clyde
                  Consultants, 1982).
                  6. Water Quality

                  a. Offshoire


                      Degradation of offshore waters is primarily associated with effluent discharges from offshore enterprises,
                  consisting of OCS activities and marine transportation. As of December 1988, some 26,64.5 wells have been
                  drilled within the Central and Western Gulf of Mexico (USDOI, MMS, 1989b). Production from these wells
                  has been estimated at 7.8 billion bbl of oil (BBO)/condensate and 73 trillion cubic feet (tcf) of gas. Potential
                  discharges associated with these activities are estimated at 13.6 million yd    3 of drill cuttings, 58.6 million bbl
                  (MMbbl) of drilling muds, and up to 66 billion bbl (Bbbl) of produced waters. Historically, the highest
                  concentration of oil and gas activity within the Gulf has taken place southward of Timbalier Bay, Louisiana,
                  and eastward to an area some 20 mi east of the Mississippi River Delta. Estimated produced water discharges
                  here range from 0.5 to 1.5 million gal/m2/yr (USDOC, NOAA, 1985). A general description of marine water
                  quality is provided in Section III.A-5.
                      During production of oil and gas, fossil or connate water located in the permeable sedimentary rock strata
                  may be brought up to the surface. On average, 8.42 bbl of produced waters are discharged for every barrel
                  of oil produced, and 17.7 MMbbI of produced water are generated per trillion cubic feet of gas. Produced
                  waters may be high in total dissolved solids, total organic carbon, petroleum hydrocarbons,some trace metals
                  and elemental sulfur and sulfide, and may be low in dissolved oxygen. Although much of the water produced
                  from OCS oil and gas operations is discharged directly at offshore production platforms into surrounding
                  waters, some of the water is piped ashore and then treated and disposed of at coastal separation facilities. The
                  major discharges from offshore oil and gas exploration and production activities include produced water, drilling
                  fluids and cuttings, ballast water, and storage displacement water. Drilling fluids are required in rotary drilling
                  for oil and gas exploration and development to remove cuttings from beneath the bit, to control well pressure,
                  to cool and lubricate the drill string, and to seal the well. Drilling fluids must be eventually disposed of for a
                  number of reasons, as must drill cuttings from the drilled formation. Although drilling discharges can be barged
                  ashore or to other sites at sea for disposal, cost and operational considerations favor on-site disposal by either
                  overboard discharge or shunting through a pipe to some depth.
                      All ocean dumping is regulated by the Marine Protection, Research, and Sanctuaries Act of 1972. A
                  USEPA permit is required for all ocean dumping of industrial wastes and municipal sludge materials. Ocean
                  dumping of sewage sludge and industrial wastes is no longer permitted. The USEPA had one designated











                                                                                                                                    111-25

                 deep-water disposal area in the Gulf of Mexico. The site was designated for the incineration of hazardous
                 wastes, but the disposal area was officially de-designated on February 27, 1991 (56 FR 8133-8135). Dredged
                 Material Disposal Sites, mostly located in State waters, are used for the disposal of dredged material from the
                 U.S. Army Corps of Engineers channel-dredging programs.
                      The Louisiana Offshore Oil Port (LOOP) is the only deep-water port in the Gulf. It is located in 35 in
                 (115 ft) of water in Grand Isle Block 59, approximately 30 kni (19 mi) from shore. The purpose of a deep-
                 water port is to provide offshore terminal facilities for offloading oil from tankers too large (typically
                 supertankers with drafts greater than 40 ft and up to 700,000 dwt) for conventional ports and to transport the
                 oil to shore via pipeline, thus avoiding the need for lightering.
                      Sulphur is produced from leases in Federal waters in the Gulf of Mexico. This information is presented
                 in Section IV.B.3.c., "Sulphur Operations."
                      The most significant contributions of marine transportation to cumulative impacts in the Gulf are from the
                 tankering of imported crude oil. Extensive refinery capacity, easy port access, and a well-developed,
                 onshore-transportation system have contributed to the development of the Gulf Coast region as an important
                 center for handling imported oil and production from other domestic sources such as Alaska and California.
                 Crude-oil tankering routinely contributes to contamination of the marine environment in two ways: (1)
                 Operational discharges occur when oily bilge water is pumped overboard and during tank cleaning and
                 ballasting. Tankers'bilges must be periodically pumped out to remove oil and water collected in the lower part
                 of the ship's hull from leaking pipes, valves, and machinery. Bilge water may first be put into a settling tank
                 to separate the oil from the water. Some vessels pump bilge water through an oil-water separator, which can
                 significantly reduce the amount of oil discharged. (2) Oil is usually discharged during tank cleaning because
                 some oil inevitably remains in the tanks after offloading. Also, ships that do not have segregated ballast tanks
                 take on seawater into "empty" oil tanks for use as ballast. When discharged, this water will contain the off
                 residue left in the tank. United States and international regulations generally prohibit any operational
                 discharges within 80 kin (50 mi) of land and require that no more than 15.8 gallons (60 liters) of oil be
                 discharged per nautical mile. In addition, no vessel may discharge more than 1115,000 of its dwt.
                      Accidental spills normally result from collisions and groundings. In 1988, about 6 percent of the tanker
                 fleet was involved in collisions or groundings (Kasoulides, 1988). Approximately 92 percent of all spills occur
                 in port (Oil Spill Intelligence Report, 1982). Since 1974, there have been 35 tanker spills of either crude oil
                 or refined products greater than 1,000 bbl in the Gulf area (USDOI, MMS, 1990a); 19 of these spills were
                 crude oil. While spills capture the attention of the general public, operational discharges occurring from tanker
                 transportation of oil account for the majority of oil discharges. The National Academy of Sciences' report
                 (NRC, 1985) estimated that total losses of oil from transportation activities ranged from 7.4 to 19.2 MMbbl
                 per year, with a best estimate of 10.7 MMbbl per year. About one-half of this amount is attributed to ballast
                 water operational discharges from oil tankers (about 5 MMbbl annually); the remainder being attributed to
                 bilge water and fuel oil released from all vessel movement in the ocean (about 2 MMbbl annually), terminal
                 operations (about 150,000 bbl annually), dry-docking (about 222,000 bbl annually), and accidental spills (about
                 3 MMbbl annually).

                 b. Coastal and Nearshore

                      River outflows into the Gulf of Mexico, primarily that of the Mississippi River, determine coastal and
                 nearshore water quality. The Mississippi River is also the most significant source of pollution to this area.
                 Major point and nonpoint sources of contaminants occurring along the Gulf Coast include the petrochemical
                 industry; hazardous waste sites and disposal facilities; agricultural and livestock farming; citrus processors;
                 chemical manufacturing industry operations; fossil fuel and nuclear power plant operations; pulp and paper
                 mill plants; silviculture; commercial and recreational fishing; municipal wastewater treatment and individual
                 septic-tank effluents; coastal maritime commerce activities, especially at ports; dredging of harbors, docks,
                 navigation channels, and pipeline canals; the USEPA dredged-material disposal-site program; and urban
                 expansion. The petrochemical industry operations include oil and gas exploration, development, and production
                 operations; pipeline transport; tanker and barge movement of both imported and domestic petroleum products











                 111-26

                 and crude oils; petroleum and petrochemical refinery and processing operations; and oil-field waste disposal.
                 There is a substantial amount of domestic waterborne commerce along the Gulf Coast that does not always
                           G1
                 use open , ulf waters. Vessels engaged in this activity generally use the Gulf Intracoastal Waterway (GIWW),
                 which follIows the coastline inshore and through bays and estuaries, and in some cases from offshore Fort
                 Myers, Florida, to Brownsville, Texas.
                     At service bases and marine terminals, hydrocarbons and other pollutants are discharged in the bilge and
                 ballast waters of support vessels docking at these facilities. The bases and support vessel; also contribute
                 contaminants through their use of antifouling marine paints and through accidental oil-spillage events and the
                 release of heavy metals and contaminated sludge. Pipecoating yards, platform-construction facilities, and repair
                 and maintenance yards contaminate surrounding waters by releasing thermal effluents, radioactive substances,
                 antifouling paint chemicals, heavy metals, and a variety of process waters, as well as sohd waste such as
                 packaging materials, metal scraps, and other debris. Gas processing plants and refineries discharge a number
                 of types of wastewaters, including cooling and boiler waters, sanitary and domestic wastewaters, and process
                 waters. These waters may be contaminated with dissolved hydrocarbons, sulfuric acid, chromium, zinc,
                 phosphates, alkaline substances, and suspended solids. The following discussion on wastewater effluents
                 discharged to surface waters by OCS-related support facilities is largely taken from NERBC (1976).
                     Wastewater effluents from OCS-related support facilities are commonly discharged to surface waters after
                 treatment. Although the degree of environmental damage, if any, is related directly to the toxic nature of the
                 discharge and the biota in the receiving waters, certain characteristics of the discharge zone are important.
                 These characteristics include the size of the effective mixing zone (dilution factor) or the ratio of discharge
                 volume to receiving volume, the flushing rate of residence time (estuaries characteristically have a slow flushing
                 rate), and the physical-chemical characteristics of the receiving waters (e.g., marine waters have a higher
                 buffering capacity than fresh or estuarine waters).
                     Construction of onshore support bases and ancillary access facilities and associated hydrologic modifications
                 would result in runoff and other nonpoint source pollution to the surrounding water bodies. Navigation
                 channels and canals and other water bodies may be diked, leveed, or impounded; piers, bulkheads, and
                 beach-stabilization actions may be undertaken. To construct the support facility, the site must be prepared,
                 roadways and bridges may need to be built, sewage and stormwater systems installed, and groundwater or
                 adjoining bodies of water accessed for water use. During preparation, the vegetation is cleared from the area,
                 the topsoil is exposed, and the soft profile is altered by grading and leveling operations. Thesoil is compacted
                 by the constant movement of heavy machinery, which in turn alters the retention properties of the soil and
                 gives rise to increased erosion and runoff from the site. Land clearing and associated development changes
                 the natural process of stormwater runoff, causing the volume and rate of runoff to increase as the natural
                 vegetation is modified.
                     Increases of nonpoint source pollution due to runoff at support facilities contribute particulate matter,
                 heavy metals, petroleum products, chemicals, and radionuclides (particularly from pipe yards) to local streams,
                 estuaries, and bays, causing temporary elevations in pollutant and turbidity levels. Two major pollutants
                 contained in this runoff include suspended solids (organic and inorganic) from exposed soil at the site and
                 contaminants such as heavy metals. Suspended solids may significantly decrease light penetration in water and
                 lead to oxygen depletion of bottom waters, and they may contain nutrients that increase growth rates of
                 endemic plant and animal populations.
                     Commercial oil and gas industrywaste facilities used by both the OCS and State oil andgas industry have
                 caused a number of environmental problems associated with their management and the disposal practices at
                 the sites, particularly along the Gulf Coast (USEPA, 1987; Hall, 1990; Subra, 1990). With regard to water
                 resources, the principal types of damage caused by these wastes include contamination of water supplies for
                 human, livestock, and agricultural uses; damage to aquatic vegetation; and impairmentof aquaticand terrestrial
                 wildlife habitats. Subra (1990) documented the damage caused by commercial facilities located in Vermilion
                 Parish, Louisiana, and reported that three of these facilities are now on the Superfund list.
                     Improper storage or disposal of drums containing solvents, corrosion inhibitors, and biocides used in drilling
                 operations also presents a potential for environmental problems. Likewise, the improper design and
                 management of storage tanks at commercial oil-field disposal facilities poses the potential for causing adverse
                 impacts to surrounding surface and ground waters and wetland areas.












                                                                                                                                111-27

                    Low dissolved oxygen (below 34 mg/1) occurs in the summer in Gulf coastal waters because of combined
               high nutrient or organic matter levels, high water temperatures, high benthic metabolic rates, low light
               penetration, and weak winds resulting in density stratification. These low dissolved-oxygen levels, called
               hypoxia, have been measured in recent years in Gulf Coast estuaries and along portions of the inner continental
               shelf.
                    A good indicator of coastal and estuarine water quality is the quality of bivalve molluscans harvested from
               its waters. Because they are filter feeders, these bottom dwellers may concentrate pollutants and pathogens,
               as well as marine biotoxins, that are unrelated to human activities. A combination of point and nonpoint
               sources affect approximately half of the harvest-limited waters in the Gulf (USDOC, NOAA, 1988b). Most
               of the productive oyster reefs in Gulf estuaries are in conditionally approved areas or areas where shellfish
               harvesting is affected by predictable levels of pollution.
                    The National Mussel Watch Program was established to determine the long-term temporal and spatial
               trends of selected environmental contaminants in bays and estuaries nationwide. Sediment and oyster samples
               are collected at some 50 sites across the Gulf of Mexico and are analyzed for contaminant concentrations,
               disease incidence, and other parameters to determine contaminant distributions. Based on Year I and II
               findings, chlorinated hydrocarbons (primarily PCB and DDT compounds) were present in Gulf coastal
               sediments. Moderately elevated concentrations of pesticides and PCB appeared along the central Louisiana
               coastline and at isolated stations in Texas (Matagorda and Galveston Bays). Maximum concentrations of
               chlorinated hydrocarbons were observed along the Mississippi to northern Florida coast and at stations in
               Tampa Bay. Based on tissue samples examined, the geographical trends in organochlorine loadings in oysters
               follow those observed in sediments (Texas A&M University, 1988).

               Central Gulf of Mexico

                    The Central Gulf region is characterized by water quality problems resulting from the discharge or release
               of industrial and domestic wastes. The Mississippi River, as well as a number of other major drainage systems,
               strongly influences the region. A major source of contaminants to the coastal and nearshore waters is from
               upstream runoff into the Mississippi River-Atchafalaya River system. A complex geography of sounds and bays
               and extensive tidal marshes acts to delay mixing, resulting in extensive areas of mesohaline (middle salinity)
               conditions. In general, compared with the waters of other states bordering the northern Gulf, Louisiana's
               estuaries and open nearshore waters are low in salinity and high in nutrient concentrations. Elevated nutrient
               levels can result in eutrophication of water bodies, causing algal blooms and fish kills. Estuaries on the
               northern coast, such as Mobile Bay and Lake Pontchartrain, receive large loads of nutrients from local sources
               and experience such problems. Hypoxia (low dissolved oxygen levels) is a recurrent summer phenomenon in
               bottomwaters off Louisiana's inner continental shelf, occasionally extending as far westward as Freeport, Texas.
               This event is linked to density stratification caused by late spring river discharges and inorganic and organic
               nutrient inputs (Boesch and Rabal", 1987). Estuaries along the Central Gulf coast where hypoxia has been
               noted include Perdido Bay, Mobile Bay, Mississippi Sound, Pascagoula Bay, Biloxi Bay, Lake Pontchartrain,
               and Calcasieu Lake. Mobile Bay is unique in that it has become hypoxic in the winter (USDOC, NOAA,
               1985).
                    Boesch and Rabalais (1989a) indicated that of the 2 MMbbI (434,772 bbl/day [BPD] from OCS activities)
               of produced waters discharged into Louisiana waters daily, 23 percent is discharged into fresh marsh, 22 percent
               into brackish marsh, and 17 percent into salt marsh environments. The remaining 38 percent is discharged into
               open embayments or nearshore Gulf waters. The largest number of discharges are located in the Terrebonne
               (199 discharge points) and Barataria (136 discharge points) estuarine systems. The largest aggregate volumes
               are reportedly discharged in Chandeleur Sound (416,000 BPD), the Mississippi River Delta (402,000 BPD),
               and Barataria Bay (363,000 BPD) estuarine systems.
                    Due to their high salinities, Gulf Coast produced waters are generally much denser than Louisiana inland
               waters. Boesch and Rabalais concluded that produced-water discharges can act as dense plumes after discharge
               into estuarine waters. Produced waters can contain various radionuclide and volatile and semivolatile organic
               hydrocarbon contaminants. Boesch and Rabalais demonstrated that produced-waters discharged into Louisiana
               waters contained high concentrations of petrogenic hydrocarbons, with sediments near these effluents











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                   contaminated with sernivolatile organic hydrocarbons. Petroleum contamination was noted in sediments up
                   to 1 km from discharge sites. Reid surveyed several Louisiana produced-water effluents and found radium 226
                   (Ra-226) levels ranging from 131 + 3 to 393 + 7 picoCuries per liter (pCi/1). The natural Ra-226 activity in
                   Louisiana surface waters is below 1.0 pCi/l; for Louisiana soils, levels range from less than 1.0 to 7.0 picoCuries
                   per gram (pCi/g) (Louisiana Dept. of Environmental Quality, 1989). Ra-226 levels for open ocean waters and
                   marine sediments average 2 pCi/I and 1-17 pCi/g, respectively. Some of these discharges have been found to
                   contain high levels of toxic metals (vanadium, copper, and arsenic) and organics; these levels represent a
                   significant negative impact to confined (poorly flushed) waterways. Because of the hydrology of such systems
                   and the particle reactive nature of the metals and organics being discharged, it has been anticipated that these
                   substances will continue to accumulate at high levels within sediments in proximity to the discharge (St. P6,
                   1990). Louisiana DEQ reports indicate that 70 percent of the produced water from oil-field operations in
                   Louisiana is discharged into surface waters.
                       In March 1991, the Louisiana State Legislature approved regulations banning the discharge of all
                   wastewater (primarily produced water) associated with oil and natural gas exploration and production activities.
                   The State's effluent guideline standards have been amended such that there shall be w, disdharge of p:-odu:. --- J
                   water into State waters after January 1, 1995, unless the discharge(s) is authorized in an approved elimination
                   schedule or is in effluent limitation compliance. Produced water shall not be discharged within 1,300 ft of an
                   active oyster lease, live natural oyster or molluscan reef, designated oyster seed bed, or seagrass bed.

                   Westem Gulf of Merico

                       The Texas coastal area has been plagued with numerous water quality problems. Most. of these problems
                   have occurred in the Houston-Galveston and Beaumont-Port Arthur areas where the majority of Texas energy
                   facilities are located. The use of the adjacent water bodies as effluent receiving systems has seriously impacted
                   surface water quality. A second influence, inland movement of offshore, saline waters into more brackish and
                   fresh waters, referred to as saltwater intrusion, has also been identified as a significant water quality problem
                   for both Texas and Louisiana. While nutrient concentrations in the Western Gulf are generally representative
                   of open Gulf surface waters, continental runoff influences nearshore surface concentrations, especially in spring.
                   Estuaries on the Texas coast where hypoxia has been noted include Sabine Pass, Galveston-East-West Bays,
                   Corpus Christi-Nueces Bays, and Lower Laguna Madre. Galveston Bay receives large loads of nutrients from
                   local sources and has experienced eutrophication problems. Texas coastal counties identified as receiving the
                   greatest heavy metal discharges include Calhoun, Harris, Orange, and Jefferson (USDOC,, NOAA, 1985).
                       Boesch and Rabalais (1989a) estimated the total volume of produced waters discharged into Texas waters
                   at 823,575 BPD, including 87,721 BPD (11%) into those designated as "inland."                The Texas Railroad
                   Commission stated there were no discharges of OCS-gencrated produced waters in Texascoastal waters. By
                   far the greatest volume of these waters is discharged into the Galveston-Trinity estuarine s- tem. Within this
                                                                                                                  Ys
                   estuary there are 208 discharge points that deliver an estimated 400,000 BPD. Matagorda-]@,avaca and Corpus
                   Christi-Nueces estuarine systems receive substantial produced-water discharges from 3:2 discharge points
                   (approximately 200,000 BPD) and 54 discharge points (approximately 60,000 BPD), respectively.

                   B. BIOLOGICAL RESOURCES

                   1. Sensitive Coastal Environments


                   a. Barrier Beaches


                       Coastal barrier landforms consist of islands, spits, and beaches that stretch in an irregular chain from
                   Alabama to Texas. These elongated, narrow landforms are composed of sand and other unconsolidated,
                   predominantly coarse sediments that have been transported and deposited by waves, currents, storm surges,











                                                                                                                                 111-29

                and winds. Barrier landforms are young coastal features. They began to form 5,000 to 6,000 years ago after
                the main mass of continental ice sheets had melted and the global rate of sea-level rise began to slow.
                     The term "barrier" identifies the structure as one that protects other features, such as bays, lagoons,
                estuaries, and marshes, from the direct impacts of the open ocean. By separating coastal waters from the
                ocean, barriers contribute to the amount of estuarine habitat available along the coast. As much as two-thirds
                of the high-value Atlantic and Gulf species of fish are considered to be directly dependent during some stage
                of their life on conditions in an estuary (Clark, 1976). Another benefit of both the barriers and their adjacent
                marshes and bays is that of providing habitats for a large number of birds and other animals, including several
                threatened or endangered species, such as the loggerhead turtle, the southern bald eagle, the alligator, and the
                brown pelican.
                     Barrier landforms are relatively low landmasses that are continually adjusting their configuration in
                response to changing environmental conditions. Landform changes can be seasonal and cyclical, such as the
                transition from a summer (swell wave) beach to a winter (storm wave) beach, or they can be indicative of a
                trend, such as a net landward movement of a feature. The long-term survival of fixed structures, such as roads,
                buildings, and power lines, constructed on a barrier landform can often be jeopardized by the changing and
                migratory nature of the barrier features. Some types of construction or stabilization projects on barrier
                landforms may actually encourage erosion, especially when the project interferes with longshore or
                shore-normal sediment movements.
                     The MMS has funded a study entitled Pipelines, Navigation Channels, and Facilities in Sensitive Coastal
                Habitats: An Analysis of Outer Continental Shelf Impacts, Coastal Gulf of Mexico (Wicker et al., 1989) to
                examine the impacts of pipeline and navigation-canal installations on barrier islands in the Western and Central
                Gulf of Mexico. The results of this study indicate that, in many cases, these projects have not resulted in
                alterations of coastal landforms or processes compared to control sites. Where jetties have been installed to
                stabilize navigation channels at barrier passes, some accelerated erosion downdrift from the jetties has been
                observed. In one case (Belle Pass, Louisiana), however, the deposition of the material excavated during
                maintenance dredging operations downdrift from the jetties resulted in slower erosion rates than compared to
                updrift locations. Wicker et al. (1989) did not find evidence that pipeline landfalls on barrier beaches had up
                to now either resulted in accelerated erosion near the crossing or formed zones of weakness where island
                breaching preferentially occurred. They did point out, however, that in the future, as islands narrow because
                of coastal erosion, open-ditch pipeline canals could become sites of accelerated erosion or island breaching.
                     Coastal barriers consist of several component environments. The beach itself consists of the foreshore,
                the sloping part of the beach facing the ocean, and the backshore, the part of the beach from the berm crest
                to the dunes. The dune zone of a barrier landform can consist of a single dune ridge, several parallel dune
                ridges, or a number of curving dune lines that are stabilized by beach grass. In most cases, the berm grades
                into the dune zone, but sometimes the berm may be missing and the beach foreshore may be adjacent to the
                dunes. Overwash fans are located behind the dunes along barriers whose dunes are breached by storm surges.
                Along more stable barriers, the area behind the dunes consists of broad, vegetated flats. These flats grade into
                wetlands and intertidal mud flats that fringe the shore of lagoons and embayments. In other areas, barriers
                can be located right against the mainland with no bay or lagoon separating the two landforms.
                     The accumulation and movements of the sedimentary deposits that make up barriers are often described
                in terms of transgressive and regressive sequences. Transgressions and regressions are related to local relative
                sea-level change and the rate of sedimentation and erosion. A transgressive sequence is one in which the shore
                moves landward and marine deposits rest on terrestrial deposits. In contrast, a regressive sequence is one in
                which terrestrial sediments are deposited over marine sediments as the land builds out into the sea.
                     Transgressive barrier landforms have a predominantly low-profile morphology. These barriers are
                characterized by narrow widths; low, sparsely vegetated and discontinuous dunes; and numerous, closely spaced
                active washover channels. Transgressive barriers are usually undergoing active erosion. Regressive barriers,
                in contrast, have high-profile morphologies including broad widths; high, continuous, and well-vegetated sand
                dunes; few, if any, washover channels; parallel accretion ridges; and thick accumulations of sand. Both
                transgressive and regressive barriers occur in the Gulf of Mexico.
                     The barrier landforms of the Central Gulf of Mexico occur in three settings. From east to west, these
                include the barrier islands of Mississippi Sound, the Mississippi River deltaic plain barriers, and the barriers











                  111-30

                  of the Chenier Plain in Louisiana. The Mississippi Sound barrier islands are relatively young, having formed
                  some thr ple to four thousand years ago as a result of shoal-bar aggradation (Otvos, 1979). The positions of the
                  islands have not changed significantly since that time. The islands are well vegetated by a southern maritime
                  climax foIrest of pine and palmetto. The islands generally are regressive with high beach ridges and prominent
                  sand dunes. Although overwash channels do not commonly occur, the islands may be overwashed during strong
                  storms. the islands in general are stable, with no trend toward erosion or thinning of the island bJ with @
                  trend toward westward migration in response to the predominantly westward-moving longshore currents. An
                  exception to this general rule is Dauphin Island, Alabama, which is essentially a low-profile transgressive barrier
                  island, except for a small Pleistocene core at its eastern end. The western end is a Holocene spit that is
                  characterized by small dunes and washover fans with marsh deposits and tree stumps exposed in the surf zone.
                  The Mississippi Sound islands are separated from each other by tidal inlets with deep, wide channels. These
                  channels have associated ebb and flood tidal deltas. Shoals are adjacent to all the barriers. The barriers are
                  separated from the mainland by the Mississippi Sound. Most of the Mississippi Sound barrier islands are
                  included in the Gulf Islands National Seashore.
                      Louisiana has the most rapidly retreating beaches in the nation. The average retreat rate for Fourchon
                  Beach over the past 100 years has been in excess of 18 m/yr. The statewide average exceeds 3.6 m/yr (Dolan
                  et al., 1982). Beaches along the deltaic plain in Louisiana fit into one of three categories, depending on the
                  stage of the deltaic cycle that the nearby landmass is experiencing. When a major distributary of the Mississippi
                  River is abandoned, subsidence results in a local sea-level transgression that transforms the active delta into
                  an erosional headland with flanking barriers. Fourchon Beach is an example of an eroding headland beach.
                  With increased age and subsidence, the barrier shoreline evolves into a transgressive barrier-island arc that is
                  separated from the mainland by a lagoon. Isles Derniers is an example of a barrier that underwent the
                  transformation from a headland beach to a barrier arc within the past century. Eventually, with continued
                  subsidence and sediment deprivation, the island ceases to exist, its remnant forming a submarine inner-shelf
                  shoal (Penland and Boyd, 1985).
                      The Chenier Plain is located farther to the west in Louisiana. Here, the coast is fronted by sand beaches
                  and coastal mudflats. The source of the mud is the discharge of the Mississippi and Atchafalaya Rivers, which
                  tends to drift westward along with the prevailing winds and associated nearshore currents. Iluid mud extends
                  from the seaward edge of the marsh grasses to a few hundred yards offshore. The mud is an extremely
                  effective wave-energy absorber. Consequently, the mainland shore is rarely exposed to effective wave action
                  except during storms. The sand beaches occurring along the Chenier Plain rest against the mainland marshes.
                  Although the beaches consist of only a thin accumulation of sand and although some parts of the coast are
                  experiencing erosion, on the average, much of the Chenier coast has a stable configuration.
                      From the Texas-Louisiana border to Rollover Pass, Texas, the Texas coast is a physiographic continuation
                  of the Chenier Plain. Here, thin accumulations of sand, shell, and caliche nodules make up beaches that are
                  migrating landward over tidal marshes. These beaches are narrow and have numerous overwash features and
                  local, poorly developed sand dunes.
                      The rest of the Texas coast is a continuous barrier shoreline. The barrier islands and spits were formed
                  from sediments supplied from three deltaic headlands: the Trinity delta, which is immediately west of the
                  Sabine River, in Jefferson County; the Brazos-Colorado Rivers delta complex in Brazoria and Matagorda
                  Counties; and the Rio Grande delta in southernmost Cameron County.
                      The Texas barriers are arranged symmetrically around these erosional deltaic headlands. Erosional and
                  accretionary barriers are about evenly split. Erosional barriers have developed along the deltaic headlands and
                  tend to be narrow, sparsely vegetated, and have a low profile and numerous washover channels. Accretionary
                  (regressive) barriers occur on either side of retreating deltaic headlands and tend to be wide;to have prominent
                  vegetated dunes; and to contain few, if any, washover channels. Accretionary barriers grade into erosional
                  barriers within interdeltaic embayments.
                      Climate is an important variable that affects the Texas coast. Texas is the only Atlantic or Gulf State with
                  a significant climate range. The climate changes from humid -subtropical in the east to semiarid in the south.
                  South of Corpus Christi, the annual evaporation exceeds the precipitation, and the landscape has an and
                  appearance. On high-profile, southern barriers, vegetation is sparse; and nearly continuous winds have built
                  high dunes.











                                                                                                                                    111-31

                      The Central and Western Gulf Coast includes barrier islands that are part of the National Park System.
                  These are the Padre Island National Seashore along the south Texas coast and the Gulf Islands National
                  Seashore offshore Mississippi. Within the Central Gulf, the Gulf Islands National Seashore includes Ship,
                  Horn, and Petit Bois Islands offshore Mississippi and the Davis Bayou area along the mainland where the park
                  administrative offices and visitor center are located. The islands include about 50 kin (30 mi) of beaches
                  fronting the Gulf of Mexico. Padre Island consists of North and parts of South Padre Islands and includes
                  about 130 kin (80 mi) of beaches. These islands were included in the National Park System because they were
                  notable examples of relatively pristine barrier settings, including broad, sandy beaches, prominent sand dunes,
                  fringing wetlands, and broad sounds or lagoons that separate the islands from the mainland. Laguna Madre
                  behind Padre Island is notable because it is one of the few examples of a hypersaline marine lagoon in the
                  United States. Congress considered the preservation of these habitats an important national goal because these
                  Pipes of settings were rapidly disappearing as a result of commercial, residential, and recreational developments.
                      Numerous specific, high-value features are located within these seashores. A wide diversity of cultural
                  resources occur within the seashores, including Fort Massachusetts, an important Civil War site on Ship Island;
                  several archaeological sites; and shipwreck sites in the vicinity of Padre Island. The islands are also important
                  recreational areas. Annual visitation to the Gulf Islands Seashore has ranged from about 250,000 to nearly
                  1,000,000 during the 1980's (USDOI, NPS, 1988). In recent years, the Padre Island National Seashore has been
                  receiving about 1,000,000 visitors annually (USDOI, NPS, 1982). The islands also are being used as habitat
                  for replenishing the populations of endangered species, including the bald eagle and the red wolf. The diversity
                  of environments within the seashores, including shorefront, wetlands, sand dune, and lagoonal habitats, offers
                  visitors opportunities for personal and educational enrichment.

                  b. Wetlands

                      Wetland habitat types occurring along the Gulf Coast include fresh, brackish, and saline marshes; forested
                  wetlands; and small areas of mangroves. Marshes and mangroves form an interface between marine and
                  terrestrial habitats, while forested wetlands occur inland from marsh areas. Weiland habitats may occupy
                  narrow bands or vast expanses and can consist of sharply delineated zones of different species, monotonous
                  stands of a single species, or mixed-plant-species communities.
                      The importance of coastal wetlands to the coastal environment has been well documented. Coastal
                  wetlands are characterized by high organic productivity, high detritus production, and efficient nutrient
                  recycling. Wetlands provide habitat for a great number and wide diversity of invertebrates, fish, reptiles, birds,
                  and mammals. Wetlands are particularly important as nursery grounds for juvenile forms of many important
                  fish species. The Louisiana coastal wetlands support over two-thirds of the Mississippi Flyway wintering
                  waterfowl population (including 20-25% of North America's puddle duck population) and the largest fur
                  harvest in North America (from 40 to 65% of the nation's total per year) (Olds, 1984).
                      Louisiana contains most of the Gulf coastal wetlands. These wetlands occur in two physiographic
                  settings--the Mississippi River Deltaic Plain and the Chenier Plain. The present wetlands on the deltaic plain
                  formed on top of a series of overlapping riverine deltas that have extended onto the continental shelf during
                  the past 6,000 or so years. These wetlands are established on a substrate of alluvial and organic-rich sediment
                  that is subject to high, natural-subsidence rates. The effects of subsidence are compounded by sea-level rise,
                  which has been occurring during the past several millenia. Under natural conditions, sedimentation encourages
                  vertical accretion of wetland areas and may offset the submergence and inundation that result from subsidence
                  and sea-level rise. Areas of the deltaic plain that are located near an active channel of the Mississippi River
                  tend to build outward, and marsh areas tend to expand. At the same time, areas located near inactive,
                  abandoned channels tend to deteriorate and erode as a result of the lack of sediment
                      The Chenier Plain, located to the west of the Atchafalaya Bay in the western part of coastal Louisiana, is
                  a series of separate ridges of shell and sand, oriented parallel or oblique to the coast, that are separated by
                  progradational mudflats that are now marshes or open water. The mudflats are built during times when the
                  Mississippi River channel is located on the western side of the deltaic plain or when minor changes in localized
                  hydrologic and sedimentation patterns favor deposition in the Chenier area.











                 111-32

                     The deterioration of coastal wetlands, particularly in Louisiana, is an issue of concern. In Louisiana, the
                 annual rdte of wetlands loss has been measured at 130 kM2        for the period 1955-1978. A recent study has
                 shown that the current rate of landloss on the Deltaic Plain area of the Louisiana coast has decreased to about
                 90 km2 per year (Britsch and Kemp, 1990). Several factors contribute to wetlands loss in coastal Louisiana,
                 including sediment deprivation (a result of a 50% decrease in the suspended-sediment loadof the river since
                 the 1950's and the channelization of the river, which has prevented overbank sediment deposjition), subsidence
                 and sea-level rise, and the construction of pipeline and navigation canals through the wetlands.
                     The MMS recently funded a study entitled Causes of Wetland Loss in the Coastal Central Gulf of Mexico
                 (Turner and Cahoon, 1987). This study investigated how wetland habitats have changed in the northern Gulf
                 of Mexico as a result of natural processes and human activities. The study's primary focus was on assessing
                 and quantifying the direct and indirect impacts of OCS-related activities on wetland areas since the 1950's.
                 Canal construction for pipelines and navigation has been the major OCS-related impacting factor.
                     Direct impacts were defined as those physical alterations that are the direct result of canal construction.
                 Direct impacts include wetlands alterations resulting from the actual dredging of the canal, the disposal of
                 dredge spoil, and any subsequent widening of the canal as a result of channel-bank erosion. Based on the
                 study's findings, OCS-related direct impacts have accounted for 16 percent of all the direct impacts that have
                 occurred in Louisiana's wetlands (12,000 ha out of 74,000 ha). Direct OCS impacts account for only 4-5
                 percent of the total wetlands loss during the period 1955/1956 to 1978. The average areal impact per kilometer
                 of constructed pipeline was estimated at 2.5 ha. In recent years, more stringent construction regulations have
                 required that pipelines installed across wetlands be backfilled with spoil material immediately after the pipeline
                 is emplaced in its ditch. The study showed that the backfilling of pipeline canals reduced direct impacts to
                 0.7-1.0 ha/km. Direct impacts per unit length of OCS-related navigation canals are about 20 times greater than
                 OCS pipeline canals.
                     Indirect impacts are those that occur as a result of hydrologic changes (salinity and drainage regimes)
                 brought on by canal construction. Indirect impacts from canals associated with the OCS program have been
                 estimated as accounting for 4-13 percent of the total amount of wetland loss that occurred in coastal Louisiana
                 between 1955/1956 and 1978 (Turner and Cahoon, 1987). Turner and Cahoon calculated this range by dividing
                 the length of OCS canal spoil banks by the length of all canal spoil banks (OCS, State onshore oil and gas,
                 general navigation, and drainage canals), and then multiplying this proportion by the range of estimates of the
                 contribution of indirect impacts in general. They assumed that the proportion of spoil banks attributable to
                 OCS dredging could be used as a direct surrogate for the proportion of indirect impacts attributable to OCS
                 dredging.
                     The MMS does not consider this method of indirect impact determination acceptable lbr analytical use
                 in the EIS. This conclusion is based on two considerations: the calculation of the proportion was based on
                 untested and inaccurate assumptions and the method did not incorporate the data collected and analyzed in
                 the body of the study, even though the data were relevant to the issue.
                     Concerning the first point, MMS questions the indirect impact percent allocation numbers as they were
                 derived by Turner and Cahoon. As stated by the authors, OCS spoil banks may have been overestimated in
                 their calculations because OCS canals and spoil banks tend to be large and thus more visible on remote-sensing
                 imagery. Also, the Turner and Cahoon study only reveals a number for the length of OCS spoil banks. The
                 length of all spoil banks (the number used in the denominator of their proportion) is not revealed within the
                 study, nor is the methodology that was used to determine this unrevealed number indicated. ]Furthermore, the
                 study defined indirect losses as all wetland losses minus the direct losses attributable to canal dredging and
                 urban, residential, and agricultural development. The contribution of sediment deprivation and subsidence
                 were not factored into the indirect losses, even though many researchers believe these factors to be the base
                 cause of wetlands loss in the area. Turner and Cahoon (1987), in essence, inappropriately allocated a
                 proportion of the impacts of sediment deprivation to OCS canals. Based on the above discussion, MMS cannot
                 validate the accuracy of the study's apportionment of indirect impacts to OCS canals.
                     In addition, the study data generated from field, laboratory, modeling, and remote-sensing analysis efforts
                 were not used in developing the indirect impact proportion number, even though much of the data were
                 relevant to the issue. An important hypothesis within the study was that the indirect impacts of canals could
                 affect wetlands through the influence of canals on saltwater intrusion and through the influence of associated












                                                                                                                                111-33

              spoil banks on sedimentation and drainage patterns. The study, however, did not document a relationship
              between saltwater intrusion and marsh loss, nor did the study show a statistically valid correlation between spoil
              banks and vertical rates of marsh accretion. The computer analyses of remote-sensing imagery did not establish
              a statistically valid relationship between either canal density or proximity to a canal and marsh loss. While the
              data did not confirm the hypothesized mechanisms of indirect impacts, the study did document a greater than
              50 percent reduction in the suspended sediment discharge of the Mississippi River since the 1950's and a
              widespread accretionary deficit within the wetlands of coastal Louisiana. These data, which did not confirm
              the hypothesized mechanisms of indirect wetland loss but suggested an emphasis on sedimentary deficits and
              subsidence as causes of marsh loss, were not brought into the methodology for assessing OCS indirect impacts.
                   To conclude, the range of indirect impact numbers derived in the study were not based on the body of data
              generated by the study, but were instead developed using an indirect and incomplete approach that could have
              been done even in the absence of the study data. The MMS considers the Turner and Cahoon estimates to
              be no more reliable and better supported by field data than any of the other attempts in the past to determine
              the role of indirect impacts.
                   In Mississippi and Alabama, the mainland marshes behind Mississippi Sound occur as discontinuous
              wetlands associated with estuarine environments. The most extensive wetland areas in Mississippi occur east
              of the Pearl River delta near the western border of the State and in the Pascagoula River delta area near the
              eastern border of the State. The wetlands of Mississippi seem to be more stable than those in Louisiana,
              perhaps reflecting the more stable substrate and more active sedimentation per unit of wetland area. Also,
              there have been only minor amounts of canal dredging in the Mississippi wetlands. Wicker et al. (1989) have
              studied the impacts of three pipeline canals in the Mississippi wetlands near the Pearl River delta. One of the
              pipelines was backfilled after construction; no noticeable geologic or botanic impacts were' observed along the
              pipeline route. The two other pipelines were installed with the open-ditch dredging method and the canals had
              not been backfilled. The open ditches did not revegetate and had, in fact, widened over time as a result of
              channel-bank erosion. No indirect impacts, however, were observed in the marshes away from the canals as
              has been frequently observed in Louisiana.
                   Most of the wetlands in Alabama occur on the Mobile River delta or along northern Mississippi Sound.
              Between 1955 and 1979, fresh marshes and estuarine marshes declined in these area by 69 and 29 percent,
              respectively. On a percentage basis, wetlands loss has occurred more rapidly in Alabama during these years
              than it did in Louisiana. Major causes of non-fresh wetland losses were industrial development and navigation,
              residential and commercial development, natural succession, and erosion/subsidence. The loss of fresh marsh
              was mainly attributable to commercial and residential development and silviculture (Roach et al., 1987).
                   In Texas, coastal marshes occur along the inshore side of barrier islands and bays and on river deltas. Salt
              marshes consisting primarily of smooth cordgrass occur at lower elevations and at higher salinities. Brackish
              marshes occur in transition areas landward of salt marshes on slightly higher elevations and at greater distances
              from saltwater bodies. Freshwater marshes of the region occur primarily along the major rivers and tributaries.
              Sparse bands of black mangroves are also found in this region. Broad expanses of emergent wetland vegetation
              do not commonly occur south of Baffiri Bay at the northern edge of Kenedy County because of the and climate
              and hypersaline waters to the south. In these areas, Spa?fina alterniflora, the most common salt-marsh grass
              elsewhere in the Gulf, occurs rarely in salt marshes. Common salt-marsh plants here include more salt-tolerant
              species such as Batis matitima and Salicomia (White et al., 1986).
                   Wetland changes observed in Texas during the past several decades appear to be driven by subsidence and
              sea-level increases. Open-water areas are appearing in wetlands along their seaward margins, while new
              wetlands are encroaching onto previously non-wetland habitat along the landward margin of wetland areas on
              the mainland, on the backside of barrier islands, and onto spoil banks. In addition, wetlands are being affected
              by human activities including canal dredging, impoundments, and accelerated subsidence caused by fluid
              withdrawals. The magnitudes of these wetland acreage changes in most of Texas have not been determined
              at the present time. In the Freeport, Texas, area along the Louisiana border, wetlands loss is occurring at rates
              similar to those occurring in adjacent parts of the Louisiana Chenier Plain. In the Sabine Basin area of coastal
              Texas, for example, 20,548 ha wetlands were lost between 1952 and 1974 (Gosselink et al., 1979).











                  111-34


                  Seagrasses

                       There are an estimated 3,000,000 ha of submerged seagrass beds in the exposed, shallow coastal waters
                  of the no@rthern Gulf of Mexico. An additional 166,000 ha confined to the natural embayments are considered
                  unexposed and are not dealt with in detail for this report. The area off Florida contains the vast majority of
                  such beds, containing approximately 98.5 percent of all coastal seagrasses in the northern Gulf of Mexico.
                  Coastal seagrass beds in Texas and Louisiana comprise approximately 0.5 percent of the exposed seagrasses,
                  with Mississippi and Alabama the remaining 1 percent of the habitat. A combination of low salinity and high
                  turbidity accounts for the narrow bands and scattered patches of seagrasses occurring between Louisiana and
                  Laguna Madre, Texas.
                       The beds grow in shallow, relatively clear and protected waters with predominantly sand bottoms. Their
                  distribution depends on an interrelationship among a number of environmental factors that include
                  temperature, water depth, turbidity, salinity, and substrate suitability. In general, the luxuriant growth of
                  seagrasses and the concomitant high diversity of associated marine species are found only within a few scattered
                  protected locations in the Central and Western Gulf of Mexico.
                       Turtle grass (77talassia testudinum), the largest of the common species, is most commonly found forming
                  dense beds at water depths of less than 10 in and may possess a rhizome buried up to 25 cm below the
                  seafloor. In terms of biomass production, turtle grass is one of the most rolific of the seagrass species, with
                  average biomass values of 500-3,100 g/M2    . and extremes up to 8,100 g/mr(values summarized from Zieman,
                  1982). Manatee grass (Syringodiumfififorme) possessesvery long, thin leaves, with vegetative reproduction from
                  the shallowly buried rhizome, which is less massive than that found in turtle grass. Shoal grass (Halodule
                  wfightit) may be considered a "pioneer species" in that it is important in colonizing disturbed areas and deeper
                  water areas beyond the ranges of the more coastal species.
                       Seagrasses dominate the aquatic floral habitat in the estuarine communities along the Texas coast.
                  Dominant species include shoal grass (Halodule wrighth) and widgeongrass (Ruppia mafitinia). These species
                  occur in abundance due to their ability to sustain salinity variations that occur in a number of the lagoon and
                  bay systems of Texas. The Laguna Madre and Copano-Aransas estuaries account for the major portion of the
                  seagrass populations. Seagrasses are less common in Corpus Christi Bay because of the Bay's greater water
                  depth. These seagrasses provide an important habitat for immature shrimp, black drum, spotted seatrout,
                  juvenile southern flounder, and several other fish species; and they provide a food source for several species
                  of wintering waterfowl.
                       The turbid waters and soft sediments of Louisiana's estuaries limit widespread distribution of seagrass beds.
                  Consequently, there are only a few areas in coastal Louisiana where seagrass beds occur. The most extensive
                  beds occur in Chandeleur Sound. Seagrasses also occur within Mississippi Sound.
                       The distribution of seagrass beds in the Central and Western Gulf have diminished during recent decades.
                  The primary factors believed to be responsible for these conditions include hurricanes, freshwater diversions
                  from the Mississippi River during flood stage into coastal areas, dredging activities, and water quality
                  degradation.

                  2. Sensitive Offshore Resources


                       The term "offshore habitats" refers to the water column and the seafloor. Seafloor (benthic) habitats are
                  the most likely to be adversely affected by offshore oil and gas operations, especially live-bottom areas,
                  deep-water benthic communities, and topographic features; these sensitive habitats are treated in some detail
                  in Sections III.B.2.a., b., and c. below.
                       Water-column biota include the plankton and nekton. In general, the diversity of planktonic species
                  decreases with decreased salinity, and biomass decreases with distance from shore.
                  Nekton are dominated by five major taxonomic categories--marine mammals, reptiles, fishes, cephalopod
                  mollusks, and crustaceans. Individuals may range over broad areas; however, most nekton are limited to
                  geographical and vertical ranges by the same environmental conditions as less motile organisms, that is,
                  temperature, salinity, and available food. Most of the fishes of the Gulf shelf habitats are temperate, with











                                                                                                                                  111-35

                incursions of Caribbean faunas; they exhibit seasonal distribution and abundance fluctuations that are probably
                largely related to oceanographic conditions.
                    Generalizations regarding water-column habitats are difficult to make because of the patchy nature of biotic
                distributions, which tend to congregate in patches of various sizes that move with the prevailing winds and
                currents. Endangered and threatened species are described in Sections III.B.1-6. below, marine mammals in
                Section III.B.3., birds in Section III.B.5., and fishes and fisheries in Sections III.B.6., and III.C.3. and 4.
                Benthic communities of the continental shelf and slope are discussed in general terms before treating the three
                specific offshore habitats most likely to be impacted by the leasing proposals.

                Confinental Shelf

                    The benthos has both floral and faunal components; the floral representatives being algae and seagrasses.
                The abundance of benthic algae is limited by the scarcity of suitable substrates and fight penetration. Rezak
                et al. (1983) recorded algae from submarine banks off Louisiana and Texas. In exceptionally clear waters,
                benthic algae, especially coralline red algae, are known to grow in water depths to at least 183 m. Offshore
                seagrasses are not conspicuous in the Central and Western Gulf-, however, fairly extensive beds may be found
                in estuarine areas behind the barrier islands throughout the Gulf as discussed in Section III.B.I.c. Seagrasses
                would be continuous around the entire periphery of the Gulf if it were not for the adverse effects of turbidity
                and low salinity of the Mississippi River effluent from the delta to Galveston (Humm, 1973).
                    Benthic fauna include the infauna (animals that live in the substrate, such as burrowing worms and
                mollusks) and epifauna (animals that live on the substrate, such as mollusks, crustaceans, hydroids, sponges,
                and echinoderms). Shrimp and demersal fish are closely associated with the benthic community. Substrate
                is the single most important factor in the distribution of benthic fauna (Defenbaugh, 1976), although
                temperature and salinity are also important in determining the extent of faunal distribution. Other lesser
                important factors include illumination, exposure to air, nutrient availability, currents, tides, and wave shock.
                Defenbaugh (1976) states that depth and/or distance from shore should also be considered as major influences
                on the benthic faunal distribution.
                    In general, the vast majority of the benthos of the Central and Western Gulf consists of soft, muddy
                bottoms dominated by polychaetes. Benthic habitats that are at the most risk to potential impacts from oil and
                gas operations are those of the topographic features, discussed in Section III.B.2.c. below, and the pinnacle
                trend live bottom, discussed in Section III.B.2.a. below.
                    Although not in the planning area for these proposed sales, the Florida Middle Ground is probably the
                best known and most biologically developed of the Eastern Gulf live bottoms, with extensive inhabitation by
                hermatypic (reef building) corals and related communities. This area is 160 km (87 nmi) west-northwest of
                Tampa and has been designated as a Habitat Area of Particular Concern (HAPC) by the Gulf of Mexico
                Fishery Management Council (50 CFR 638). Within the HAPC, bottom longlines, traps and pots, and bottom
                trawls are prohibited. The taking of any coral is prohibited except as authorized by permit from the National
                Marine Fisheries Service (NMFS).
                    The Florida Middle Ground represents the northernmost extent of coral reefs and their associated
                assemblages in the Eastern Gulf (Bright and Jaap, 1976; Rezak and Bright, 1981). The Middle Ground is
                similar to the Flower Garden Banks off Texas--typical Caribbean reefal communities--although both are
                depauperate in terms of the number of species present, probably because it is considered to be at the northern
                limit of viable existence for these types of coral communities (Bright, personal comm., 1975; Hopkins et al.,
                1977). Coral reef communities are exceedingly complex and have been treated at length by Bright and Jaap
                (1976) and Faulkner and Chesher (1979). It is sufficient to state that, in general, hermatypic corals require
                temperatures of 18'-300C, with the optimum at about 260C; salinities from 36-40 ppt, with the optimum at 36
                ppt; little pollution and nutrient load; and adequate light (i.e., little turbidity). In the Caribbean they may grow
                as deep as 80 m, while in the Gulf they seem to be limited to a depth of about 40 m (Bright and Jaap, 1976).
                The Middle Ground reefs rise essentially from a depth of 35 m, and the shallowest portions are about 25 m
                deep. Significantly productive areas comprise about 12,126 ha (29,943 ac).
                    The Florida Middle Ground supports numerous Caribbean fish, corals, and invertebrates. This is probably
                due to the intrusion of the Loop Current, short periods of low temperatures, and high organic productivity.











                  111-36

                  A total of 197 species of fish, with largely tropical West Indian affinity, have been reported at the Middle
                  Ground (Rezak and Bright, 1981). The benthos of the Florida Middle Ground is composed of hard and soft
                  corals, sponges, and algae. The hard corals include Madracis decactis, Porites divaricata, Dichocoenia stellaris,
                  and Dichocoenia stokesii. Octocorals, relatively minor components of other Gulf reefs, are prominent at the
                  Middle Ground. Dominant octocorals include Muricea elongata, M. laxa, Eunicea calyculata, and Plexaura
                  flexuosa. The biota of the Middle Ground is sensitive to environmental change, as documented by Rezak and
                  Bright (1981).
                       Although also not in the planning area for these proposed sales, the Florida Keys comprise an important
                  shallow-water, tropical, coral-reef ecosystem that is unique on the continental shelf of North America. Coral
                  reefs are closely interrelated and interdependent with other marine and terrestrial communities that compose
                  the coastal ecosystem. Energy, chemical constituents, and mobile species move between the reefs and other
                  communities, including mangrove, seagrass, sedimentary, and hardground communities. Inaddition, the coral
                  reefs of the Keys are important to the economy of Florida. Commercial and recreational fishing, as wen as
                  such nonconsumptive uses as boating, scuba diving, snorkeling, and educational and natural history activities
                  are big businesses (Jaap and Hallock, 1990a).
                       Jaap and Hallock (1990) have recently reviewed the Florida Keys ecosystem. A briel'summary of that
                  work may be found in Section III.B.2. of the Final EIS for Sales 131, 135, and 137 (USDOI, MMS, 1990a).
                       In addition to their ecological, recreational, and commercial importance, the Keys have a certain intrinsic
                  value aesthetically. This value, while difficult to quantify, is certainly significant and is partly recognized by the
                  establishment of three National Marine Sanctuaries in the Keys. Looe Key and Key Largo are popular
                  recreational sites with active educational programs. The large Florida Keys National Marine Sanctuary has
                  recently been designated, and a management plan for it is currently under development. These, along with
                  the potential designation of the Flower Garden Banks as a Marine Sanctuary, demonstrate the commitment
                  of the nation to preserve the important and relatively rare coral reef ecosystems.

                  Continental Slope and Deep Sea

                       The deep-sea area of the northern Gulf of Mexico is much less known than the shelf. Pequegnat (1983)
                  reported observations based on 264 oceanographic stations between 150 and 3,850 in in an area including the
                  DeSoto and Alaminos Canyons, the Mississippi Trough and Fan, and the Sigsbee Abyssal Plain. There are
                  some remarkable biotal differences in the deep ecosystem of the Gulf. In fact, the biotal differences justify
                  referring to the Western Gulf (corresponds to WPA and CPA) as the "true" Gulf and the Eastern Gulf
                  (corresponds to EPA) as a divergence of the Atlantic Ocean via the Caribbean Sea (Pequegnat, 1983; LGL
                  Ecological Research Associates, Inc. and Texas A&M University, 1986).
                       The highest values of surface primary production are found in the upwelling area north of the Yucatan
                  Channel and in the region around surface DeSoto Canyon. In the oceanic region, the Western Gulf is, in
                  general, more productive than the Eastern Gulf. It is generally assumed that, perhaps except for brief periods
                  during major plankton blooms, the zooplankton consume all the phytoplankton produced. In turn, they excrete
                  a high percentage of their food intake as feces that sink to the bottom. Most of the herbivorous zooplankters
                  are copepods, with calanoids the dominant group (Pequegnat, 1983).
                       The topographic and physical oceanographic conditions present at East Breaks in the Western Gulf are
                  such that a nutrient-rich upwelling could be expected in the vicinity. The NMFS has reported that the area
                  is an important recreational billfishing area. The upwelling may contribute to this fishery.
                       Beneath the euphotic zone and extending to within a meter or so of the bottom is a huge mass of water
                  that beyond the shelf is largely devoid of sunlight. This is the aphotic zone where photosynthesis cannot occur
                  and where the processes of food consumption, biological decomposition, and nutrient regeneration take place
                  in the cold and dark waters. The lowermost layer is the bottom itself together with the contiguous water a
                  meter or so in thickness. This is the benthic zone, repository of sediments from above, where nutrient storage
                  and regeneration take place in association with the solid and semisolid substrate (Pequegnat, 1983).
                       The slope is a transitional environment influenced by processes on the shelf and the abyssal Gulf. This
                  transition applies both to the pelagic and the benthic realm. The general conclusions that may be reached are
                  as follows: (a) the shelf phyto- and zooplankton are more abundant, more productive, and seasonally more











                                                                                                                                111-37

               variable than the deep Gulf plankton; (b) in these respects, the slope plankton are intermediate but closer to
               the condition of the deep Gulf, and (c) each of the three regions is characterized by some planktonic species
               that are more or less specific to a particular zone. Some east-west differences have been noted, especially
               among the diatom species. These species have also been interpreted as representing the differences between
               normal Gulf waters and those influenced by Mississippi River water (Pequegnat, 1983).
                   Most of the benthic fauna of the deep slope and abyssal plain are restricted to these depths and are not
               found elsewhere. The 450-m isobath defines the truly deep-sea fauna. The deep-water benthic fauna have
               been characterized into seven faunal assemblages by Pequegnat (1983) and confirmed by LGL Ecological
               Research Associates, Inc. and Texas A&M University (1986):

                        The Shelf/Slope Transition Zone (150450 m) is a very productive part of the benthic
                        environment Demersal fish are the dominant species, many of them reaching their maximum
                        populations in the zone. Asteroids, gastropods, and polychaetes are common.

                        The Archibenthal Zone - Horizon A Assemblage is located between 475 and 750 m.
                        Although less abundant, the demersal fish are a major constitutent of the fauna, as are
                        gastropods and polychaetes. Sea cucumbers are more numerous. Horizon B, located at
                        775-950 m, represents a major change in the number of species of demersal fish, asteroids,
                        and echinoids, which reach maximum populations here. Gastropods and polychaetes are still
                        numerous.


                        The Upper Abyssal Zone is located between 975 and 2,250 m. Although the number of
                        species of dernersal fish drops, the number that reaches maximum populations dramatically
                        increases. This indicates a group uniquely adapted to the environment. Sea cucumbers
                        exhibit a major increase, and gastropods and sponges reach their highest species numbers
                        here.


                        The topographic and physical oceanographic conditions present at East Breaks in the Western
                        Gulf are such that a nutrient-rich upwelling could be expected in the vicinity. The NMFS has
                        reported that the area is an important recreational billfishing area. The upweftg may
                        contribute to this fishery.

                        At the onset of the Mesoabyssal Zone - At Horizon C (2,275-2,700 m) a sharp faunal break
                        occurs. The number of species reaching maximum populations in the zone drops dramatically
                        for all taxonomic groups.

                        The Mesoabyssal Zone - Horizon D Assemblage, located at 2,725-3,200 m, coincides with the
                        lower part of the steep continental slope in the Western Gulf. Since the Central Gulf is
                        dominated at these depths by the Mississippi Trough and Mississippi Fan, the separation of
                        Horizon C and D assemblages is not as distinct in the Central Gulf. The assemblages differ
                        in species constitution.

                        The Lower Abyssal Zone is the deepest of the assemblages at 3,225-3,850 m. Megafauna is
                        depauperate. The zone contains an assemblage of benthic species not found elsewhere.

                   Chemosynthetic communities of the deep sea are discussed in Section III.B.2.b. below.

               a. Live Bottoms (Pinnacle Trend)

                   The northeastern portion of the Central Gulf of Mexico exhibits a region of topographic relief, the
               "pinnacle trend," between 67 and 110 m (220 and 360 ft) depth. The pinnacles appear to be carbonate reefal











                   111-38

                   structures in an intermediate stage between growth and fossilization (Ludwick and Walton,'1957). The region
                   contains a variety of features from low to major pinnacles, as well as ridges, scarps, and relict patch reefs. It
                   has been postulated that these features were built during lower stands of the sea during the rise in sea level
                   following the most recent ice age. The heavily indurated pinnacles provide a surprising amount of surface area
                   for the growth of sessile invertebrates and attract large numbers of fish.
                       The@ pinnacles are found at the outer edge of the Mississippi-Alabama shelf between the Mississippi River
                   and DeSoto Canyon. The bases of the pinnacles rise from the seafloor between 50 and 100 in with vertical
                   relief ocIcasionally in excess of 20 m. These features exist in turbid water and contain limited biotal coverage.
                   Pinnacles photographed in 1985 showed biota similar to the transitional antipatharian -zone assemblage
                   described by Rezak (CSA, 1985). These pinnacles may provide structural habitat for a variety of pelagic fish.
                   Schroeder et al. (1988) have noted the diversity of habitat types in the offshore waters of Mississippi-Alabama.
                   The MMS, through the studies program, is further studying the extent and importance of the pinnacle area.
                       With the exception of the region defined as the pinnacle-trend areas, the substrate in waters shallower than
                   67 in of the Central Gulf is a mixture of mud and/or sand (Vittor and Associates, Inc., 1985). The live-bottom
                   surveys required by MMS and conducted in the eastern portions of the area have also revealed sand or mud
                   substrate. These areas are not conducive to "live-bottom" community growth since a hard substrate is needed
                   for epifaunal attachment. As the substrate grades to carbonate sand in the Eastern Gulf, the potential for "live
                   bottoms" increases.
                       The following description of the pinnacle-trend region is taken from the Mississippi-Alabama Marine
                   Ecosystems Study (MAMES), as described by Brooks et al. (1989).

                                Biological assemblages dominated by tropical hard-bottom organisms and reef fishes
                            occupy a variety of topographic features that exist between 60 and 110 in in the northeastern
                            Gulf of Mexico between the Mississippi River and DeSoto Canyon. The origins of the
                            carbonate features vary. Some are small, isolated, low to moderate reefal features or outcrops
                            of unknown origin. Some appear to be hard substrates exposed by erosion during; sea level
                            still-stands along late Pleistocene shorelines. Others appear to be small reefs that existed near
                            these shorelines. The largest features appear to have been offshore reefs. Formation of the
                            largest features probably occurred prior to the Holocene Transgression. Some additional
                            growth of these features and growth of other smaller reefs on exposed substrates may have
                            taken place during the early transgressional period. The structure of the summits of some
                            reefs may also have been modified by Holocene erosional events following their initial period
                            of growth (namely, the flat-topped reefs). Most currently appear to be deteriorating under
                            the influence of bioerosional processes.
                                The hermatypes that contributed to the development of these structures probabl@ included
                            coralline algae, reef-building corals, bryozoans, foraminiferans, and molluscs, among others.
                            Present-day production of calcium carbonate is probably limited to an impoverished calcareous
                            algae population on features above 70-75 in. Features below this depth can most: likely be
                            considered completely drowned reefs.
                                The topographic features in the northeastern Gulf may be of similar age and origin to
                            those that exist in a number of areas along the Gulf of Mexico OCS and the east coast of the
                            United States. The depth ranges of many of these features are similar, and most are
                            non-growing reefs inhabited by tropical to warm temperate, hard-bottom organisms most
                            commonly found below the depths of living coral reefs.
                                Present-day biological assemblages on features in the northeastern Gulf are dominated
                            by suspension feeding invertebrates. Populations are depauperate on features of low
                            topography, those in habitats laden with fine sediments and at the base of larger features
                            (where resuspension of sediments limits community development). On larger features, the
                            diversity and development of communities appears to depend on habitat complexity; that is,
                            containing extensive reef flats on their summits, there are rich assemblages distinguished by
                            a high relative abundance of sponges, gorgonian corals (especially sea fans), crinoids, and
                            bryozoans. Due to the generally accordant depth of flat-topped reefs (62-63 in), coralline











                                                                                                                               111-39

                                 algae are also in abundance. Other organisms on reef flats include holothurians, basket stars,
                                 and myriads of fish (mostly the roughtongue bass, Holanthias martinicensis). On reefs lacking
                                 this reef-flat habitat, as well as on reef faces of flat-topped features, the benthic community
                                 is characterized by a high relative abundance of ahermatypic corals (both solitary and colonial
                                 scleractinians). Other frequently observed organisms on these rugged, often vertical reef faces
                                 include crinoids, gorgonians, sea urchins, and basket stars.
                                     Human impact in these environments appears to be minimal at present Discarded
                                 debris, though present at many sites, was not abundant and, therefore, poses little threat to
                                 the environment. Cables and ropes can affect shallower reef communities, but probably have
                                 little impact at these depths once they become tangled on or lodged against reefal structures.
                                 Fishing pressure on these relatively small features may reduce the population of the larger,
                                 commercially important species, and may explain the abundance of smaller individuals of
                                 unprofitable species on heavily fished reefs.

                        b. Deep-water Benthic Communities

                            Chemosynthetic: clams, mussels, and tube worms, similar (but not identical) to the hydrothermal vent
                        communities of the eastern Pacific (Corliss et al., 1979) have been discovered in the deep waters of the Gulf
                        and have been the subject of numerous MMS site-specific reviews. These cold-water communities are
                        associated with seismic wipe-out zones and hydrocarbon seep areas between water depths of 400 and 1,000 in
                        (Kennicutt and Gallaway, 1985; Brooks et al., 1986a). Clams of the genus Calyptogena, probably C.
                        ponderosa, were identified from the Gulf seep communities. Chemosynthetic worms from the family
                        Lamellibrachiidae and a new undescribed family were found in the Gulf seep communities. The seep
                        communities are characterized by white bacterial mats; large dense beds of tube worms, clams, and mussels;
                        numerous small gastropods; and galatheid crabs (Kennicutt and Gallaway, 1985; LGL Ecological Research
                        Associates, Inc. and Texas A&M University, 1986).
                            After the initial discovery of the chemosynthetic: organisms in the Central Gulf, 12 trawls were conducted
                        by Texas A&M University in the Green Canyon Area in 300- to 500-m water depth. Chemosynthetic organisms
                        were collected at most of these trawl transects. Additionally, through separately funded studies, phototransects
                        documented the location of chemosynthetic organisms at various widespread locations in the Green Canyon
                        Area in water depths from 450 to 950 in. The Offshore Operators Committee funded a study through Texas
                        A&M University (Brooks et al., 1986b) to determine the extent of these communities in the Gulf and their
                        correlation with hydrocarbon seepage. This study included 39 stations located between 180- and 900-m water
                        depth and included the East Breaks, Garden Banks, Green Canyon, Ewing Bank, Atwater Valley, and
                        Mississippi Canyon lease areas. Thirty of the stations sampled exhibited shallow seismic wipe-out zones.
                        (Wipe-out zones are characteristic of gas-charged, hydrate-containing, and oil-stained sediments.) Of the 39
                        stations sampled, 28 yielded chemosynthetic organisms. Only two of the nonchemosynthetic stations exhibited
                        conditions where chemosynthetic communities might be expected, that is, wipe-out zones, oil-stained sediments,
                        gas pockets, or sediment H2S odor. The study indicates that there is a strong correlation between seismic
                        wipe-out zones and the occurrence of chemosynthetic: communities. Chemosynthetic organisms can thus be
                        expected to occur on or near these wipe-out zones throughout the Gulf where water depths are comparable
                        tothestudyarea. Additionally, chemosynthetic organisms are widespread throughoutthe deep slope, although
                        normally concentrated in very sparse concentrations of less than one animal per in       2 (Brooks et al., 1986b).
                            In late 1986, LGL Ecological Research Associates, Inc., and Texas A&M University conducted further
                        surveys as part of the MMS deep-sea study using the research submersible Johnson-Sea Link L The surveys
                        discovered a surprisingly large and diverse community of chemosynthetic tube worms and mussels at a site of
                        natural petroleum and gas seepage, over a salt diapir, in Green Canyon Block 185. The seep site, dubbed Bush
                        Hill, is a small knoll that rises about 40 in above the surrounding scafloor of about 540-m water depth. The
                        following description of this community, the densest and most diverse so far discovered, is from Brooks et al.
                        (1989):











                  11140

                       The, sediment in this area consists of silty-clay and is of considerable thickness, although
                  much of the sedimentary facies have been wiped out by rising gas and liquid and by in situ
                  formation of authigenic carbonate and sulfides.
                       The; sediments of the depauperate periphery are pale ochre with an easily disturbed
                  flocculent layer. Traces of fish are seen, including burrows and shallow depressions and
                  mounds; but very few organisms are seen. Carbonate outcroppings can be seen, ranging from
                  rubble to prominent boulders. The larger boulders are topped by gorgonians, which are in
                  turn frequently encrusted by large ophiuroids. Large colonies of the scleractinian coral
                  Lophelia sp. are also seen attached to the exposed portions of the boulders. Filigreed patches
                  of bacteria can be observed on the sediments. Closer to regions of greater community density,
                  the bacteria patches increase in area and are interspersed with the slender (3.5 mm) black
                  tubes of a pogonophoran tube worm. The most prominent feature of the dense area of the
                  community are bushes of tube worms.
                       Two species of vestimentiferan tube worms have been collected from Bush Hill. An
                  undescribed mytilid mussel forms discrete beds on both soft sediments and among carbonate
                  outcroppings. Mussels and tube worms have been observed together; however, the larger
                  mussel beds usually contain only stunted tube worms, if any. The beds are irregular in shape,
                  often in close proximity to each other, and range in area from less than 1 in 2to approximately
                  20 ni@
                       Streams of bubbles, primarily methane, can be observed escaping from the substrate, both
                  within the mussel beds and in their immediate vicinity. Some of these bubble streams are
                  intermittent releases; others continued throughout the period of observation. Disturbance
                  of the bottom in the vicinity of methane streams can cause the release of large oil globules,
                  which float upward. Such releases of oil can also be observed in other locations, usually as
                  a result of some disturbance of the bottom. A dense orange-colored mat of bacteria often
                  covers the oily sediments.
                       A diverse assemblage of common slope fauna has been observed at Bush HER.
                  Bathypelagic organisms include tunicates, squid, and trichiurid fishes. Crustaceans include
                  decapod crabs, shrimp, and a giant isopod (Bathynomous gigas).

              Other chemosynthetic sites have similar biota, although none known are so dense and diverse as Bush Hill.
              Investigations into these new and interesting areas continue. Brooks et al. (1987) showed that the worms,
         clams, and mussels contain autotrophic bacterial symbionts. The worms and clams contain intracellular sulphur
         bacterial symbionts, while the mussel symbionts are methane based.               Evidence for the presence of
         nitroeen-fixine bacteria in the community was also presented. Kennicutt et al. (1988) demonstrated the
         relationship lt@etween the chemical environment induced by hydrocarbon seepage (H2S, CH4, and oil) and
         chemosynthetic processes on the deep slope. These environments are closely linked to the massive seepage
         of oil and gas (and can be detected in the geophysical record by the presence of "Mpe-out" zones) and the
         resulting anaerobic, H2S-rich sedimentary conditions. The natural seepage of hydrocarbons may represent a
         significant source of hydrocarbons to the deep oceans, and chemosynthetic biomass appears to be an important
         component of the slope ecology in the areas studied. MacDonald et al. (1989) demonstrated a very close
         relationship between the density of tube worms and mussels and concentration of organic material derived from
         the seep. Brooks et al. (1989) described the chemosynthetic communities studied by their group at Texas A&M
         University, including Bush Hill, described above.
              Similar communities have also been discovered in the Eastern Gulf, at the base of the Florida Escarpment,
         in 3,270-m water depth (Paull et al., 1984). These, too, have been shown to rely on chemosynthesis for organic
         production (Paull et al., 1985). A full description of these scarp communities may be found in Hecker (1985).
              Cary et al. (1989) have shown that although the vestimentiferan worm and the mussel live contiguously,
         they rely on different substrates for chemoautotrophy. A variety of analytical methods indicate that the tube
         worm relies on sulfide oxidation and the seep mussel on methane oxidation for growth.
              Chemosynthetic communities have been a source of controversy over the past few years, in part because
         of the unusual environmental requirements and the hypothesized sensitivity of the communities to oil and gas











                                                                                                                                    111-41

                 activities. The MMS requires site-specific surveys of bottom-disturbing actions in water depths greater than
                 400 m in order to judge the potential of the region for supporting chemosynthetic organisms. Figures 111-2 and
                 111-3 delineate the regions of the Gulf of Mexico in which these reviews have been made. The review of
                 site-specific activities has been accomplished since 1984, with over 80 blocks examined to date. NTL 88-11,
                 issued by the MMS, Gulf of Mexico OCS Regional Office in late 1988 and effective on February 1, 1989,
                 formalized the process. The NTL was published and mailed to all affected leaseholders.

                 c. Topographic Features

                     The shelf and shelf edge of the Central and Western Gulf are characterized by topographic features that
                 are inhabited by benthic communities (Figure 111-4). The habitat created by the topographic features is
                 important in several respects: they support hard-bottom communities of high biomass, high diversity, and high
                 numbers of plant and animal species; they support, either as shelter, food, or both, large numbers of
                 commercially and recreationally important fishes; they are unique to the extent that they are small, isolated
                 areas of such communities in vast areas of much lower diversity, they (especially the East and West Flower
                 Garden Banks) provide a relatively pristine area suitable for scientific research; and they have an aesthetically
                 attractive intrinsic value.
                     The benthic organisms on these features are temperature and light limited. The 161C-isotherm is stressful
                 for most coral and is considered the lower limit for coral growth (Rezak et al., 1983). Elevated temperatures
                 can also cause thermal stress by causing the corals' zooxanthellae to be expelled. Where light is limited, coral
                 growth is inhibited. Therefore, coral growth is limited by water depth and by distance from surrounding
                 substrate and nepheloid layer. Because the coral communities must be close enough to the surface of the water
                 for adequate light penetration and yet removed from the seafloor to escape the effects of the nepheloid layer,
                 the topographic features (or banks) present the proper conditions for coral growth.
                     Rezak et al. (1983 and 1985) identified seven distinct biotic zones on the banks of the Gulf. None of the
                 banks contain all of the seven zones. The zones are divided into the following four categories dependent upon
                 the degree of rcef-building activity in each zone.

                 Zones of Major Reef Building and Pfirnary Production

                     Diplona-Montastrea-Pontes Zone

                     This zone is characterized by 18 hermatypic coral species. The dominant species of the zone in order of
                 dominance are Montastrea annularis, Diploria strigosa, Montastrea cavernosa, Colpophyllia spp., and Porites
                 asteroides. The biotic zone was named before the order of dominance was known; therefore, the name does
                 not reflect the true order of dominance. Coralline algae are abundant in the Diploria-Montastrea-Porites Zone,
                 adding substantial amounts of calcium carbonate to the substrate. Leafy algae are sparse, probably due to
                 grazing. Typical sport and commercial fish that frequent the Diploria-Montastrea-Porites Zone include grouper,
                 hind, amberjack, barracuda, red and vermilion snapper, cottonwick, porgy, and creole fish. This high-diversity
                 coral-reef zone is found only at the East and West Flower Garden Banks in water depths less than 36 m.

                     Madracis Zone and Leafy Algae Zone

                     The Madracis Zone is dominated by the small branching coral Madracis mirabilis, which produces large
                 amounts of carbonate sediment. In places, large (possibly ephemeral) populations of leafy algae dominate the
                 Madracis gravel substratum (Leafy Algae Zone). The Madracis Zone appears to have a successional
                 relationship with the Diploria-Montastrea-Porites Zone. Madracis remains build up the substrate and allow the
                 successional species to grow. The zone occurs at the Flower Gardens on peripheral parts of the main reefal
                 structure between 28 and 46 m.







                                                                                                                                                                         MISSISSIPPI)
                                                                                       LOUISIANA



















                                                                                                 400 M
                                                                                                                              *Swa W
                                                                                                                                    0" A          Sh


                                                                     LEGEND

                                                      Blacks h... d.ne.               of h.mo.ynthwti.
                                                      organisms have been found (submersible studies by
                                                      Texas - & M researchers).
                                                  A   81 ocks where chemoynthetic orqonisms have been
                                                      recovered by trawl sampling (din5ity Of organisms unknown).

                                                  ï¿½   Blocks where chemosynthetic organisms m oy be found
                                                      (as derived from the operator's hazard survey
                                                      or Texas A & M data).
                                                  ï¿½   Blocks which are unlikely to suppq It thfe growth of
                                                      chem osynthetic organisms (as d.,ved r.m  the
                                                      operator's hazard information).








                           Figure 111-2. Location and Description of Chemosynthetic Communities in the Central Gulf of Mexico.









                                                        TEXAS

                                                                                                                                                                               LEGEND

                                                                                                                                                           *    Blocks where dense communities of che
                                                                                                                                                                organisms have been found (submersible
                                                                                                                                                                Texas A & M researchers).
                                                                                                                                                           A    Blocks where chemosynthetic organisms
                                                                                                                                                                recovered by trawl sampling (density of

                                                                                                                                                           0    Blocks where chemosynthetic organisms
                                                                                                                                                                (as derived from the operator's hazard
                                                                                                                                                                or Texas A & M data).

                                                                                                                                                           In   Blocks that are unlikely to support the
                                                                                                                                                                chemosynthetic organisms (as derived fr
                                                                                                                                                                operator's hazard information).



                                                                                                                                                                                             A          4
                                                                                                                                                                           son
                                                                                                                        of                                                      an :2
                                                                                                                       *A           00                            AA AA               8

                                                                                                                                                                                                00



                                                                                                                                                                                            00
                                                                                                                                                                                            06
                                                                             me










                                                                                                      -------------------

                                                                           400m




                       Figure 111-3. Location and Description of Chemosynthetic Communities in the Western Gulf of Mexico.










                                                                                                                                                                                                                                          MIS

                                                                                                                                                                LOUISIANA
                                                             TEXAS
                                                                                                                                                                                                           NEW      OkLEAN

                                                                                            HOUSTON




                                                                                                                      GALVESTON




                                                                                                    20M
                                                                                                                                     Pile

                                                                                                                           Stwtson
                                                                                                                      .32 F.thi-       *Lump    9@ 219 rathom              Aidordico.
                                                                            Big  &. Small  Dunn Bar      foom    . .  . .I.I.,*.                                                 4 *Fl.hn.f            Eiing
                                                                                                                                 E.W
                                                                                                                                            4 R              M    rc6                   9kkulo                   Di.phw.
                                                                                                        200M                           G-d.                                                1.                        .
                                                                                   Baker ai Ii. Oak.,                              We.,                      4D       R
                                                                                                                                 Fl-0                 BY                             Par@er
                                                                                                                                                    Geyer             Se..
                                                                              Aranea.                                            Garden                      El-      ldnqr    S...t
                                                                             H..plt.1  &  N. H..pffW
                                               0.                       0 Suth.m
                                      CORPUS
                                       CHRISTI


                                                                    0 Dream
                                                                  0 Blackflsh














                                Figure 111-4. Location of Topographic Features.











                                                                                                                                  111-45

                     Stephanocoenia-Millepora Zone

                     The Stephanocoenia-Millepora Zone is inhabited by a low-diversity coral assemblage of 12 hermatypic
                corals. The eight most conspicuous corals in order of dominance are Stephanocoenia rnichelini4 Millepora sp.,
                Montastrea cavernosa, Colpophyllia spp., Diplopia sp., Agaricia spp., Mussa angulosa, and Scolyrnia sp. The
                assemblages associated with the Stephanocoenia-Millepora Zone are not well known. Coralline algae are most
                conspicuous in this zone. Reef fish populations are less diverse. The American thorny oyster (Spondylus
                americanus) appears numerous in the zone. The lower diversity coral reefs are found at the Flower Gardens,
                McGrail Bank, and Bright Bank. The depth range of this zone is between 36 and 52 m.

                     Algal-Sponge Zone

                     The Algal-Sponge Zone is the largest of the reef-building zones in terms of area. The dominant organisms
                of the zone are the coralline algae, which are the most important carbonate-nodule producers. The algae
                nodules range from 1-10 cm in size and cover 50-80 percent of the bottom. The depth range of this zone at
                each bank varies depending on the conditions at the bank, but generally the range is between 55 and 85 in.
                The habitat created by the algae nodules supports communities that are probably as diverse as the coral-reef
                communities. Most of the leafy algae found on the banks occur in this zone and contribute large amounts of
                food to the suffoundingcommunities. In addition to the coralline algae, calcareous green algae (Halimeda and
                Vdotea) and several species of hermatypic corals are major contributors to the substrate. Deep-water
                alcyonarians; are abundant in the lower Algal-Sponge Zone. Sponges, especially Neofibularia nolitangere, are
                conspicuous. Echinoderms are abundant and also add to the carbonate substrate. Small gastropods and
                pelecypods are also abundant. Gastropod shells are known to form the center of some of the algal nodules.
                Characteristic fish of the Algal-Sponge Zone are yellowtail reeffish, sand tilefish, cherubfish, and orangeback
                bass.
                     Partly drowned reefs are a major biotope of the Algal-Sponge Zone. They are defined as those reefal
                structures covered with living crusts of coralline algae with occasional heads of hermatypic corals. In addition
                to the organisms typical to the rest of the Algal-Sponge Zone, the partly drowned reefs are also inhabited by
                large anemones, large comatulid crinoids, basket stars, limited crusts of Millepora, and infrequent small colonies
                of other hermatypic species.

                Zone of Minor Reef Building

                     Millepora-Sponge Zone

                     The Millepora-Sponge Zone occupies depths comparable to the Diploria-Montastrea-Porites Zone on the
                claystone-siltstone substrate of the Texas-Louisiana midshelf banks. One shelf-edge carbonate bank, Geyer
                Bank, also exhibits the zone but only on a bedrock prominence. Crusts of the hydrozoan coral, Millepora,
                sponges, and other epifauna occupy the tops of siltstone, claystone, or sandstone outcrops in this zone.
                Scleractinian coral heads and coralline algae are rare.

                Transitional Zone of Minor to Negligible Reef-Building

                     Antipatharian Zone

                     This transitional zone is not distinct but blends in with the lower Algal-Sponge Zone. It is characterized
                by an abundance of antipatharian whips growing with the algal-sponge assemblage. With increased water
                depth, the assemblages of the zone become less diverse, characterized by antipatharians, comatulid crinoids,
                few leafy or coralline algae, and limited fish (yellowtail redfish, queen angelfish, blue angelfish, and spotfin
                hogfish). Again, the depth of this zone varies at the various banks but extends generally to 90 m.











                  111-46

                  Zone of No Reef Budding

                      Nepheloid Zone

                      High turbidity, sedimentation, and resuspension occur in this zone. Rocks or drowned reefs are covered
                  with a thin veneer of sediment Epifauna are scarce. The most noticeable are comatulid crinoids, octocoral
                  whips and fans, antipatharians, encrusting sponges, and solitary ahermatypic corals. The fish fauna are different
                  and less diverse than those of the coral reefs or partly drowned reefs. These fish species include red snapper,
                  spanish flag, snowy grouper, bank butterflyfish, scorpionfishes, and roughtongue bass. This zone occurs on all
                  banks, but its depth differs at each bank. Generally, the Nepheloid Zone begins at the limit of the
                  Antipatharian Zone and extends to the surrounding soft bottom.
                      Figure 111-4 depicts the location of the topographic features in the Western and Central. Gulf. Table 111-4
                  describes the biotic zones found or expected at each bank and gives the depths of the bank crest and
                  surrounding seafloor.
                      Of the topographic features depicted in Figure 1114, 16 are located in the Central Gulf.

                                   Shelf-Edee Banks                            Midshelf Banks

                                   Bright Bank                                 Sonnier Bank
                                   McGrail Bank                                29 Fathom Bank
                                   Rankin Bank                                 Fishnet Bank
                                   Alderdice Bank
                                   Rezak Bank
                                   Sidner Bank
                                   Ewing Bank
                                   Jakkula Bank
                                   Bouma Bank
                                   Parker Bank
                                   Sackett Bank
                                   Diaphus Bank
                                   SweetBank

                      (Rankin and 29 Fathom Banks are located along the dividing fine between the Central and Western Gulf
                  and, therefore, are considered on both.)
                      The shelf-edge banks generally exhibit the zonation exhibited at the Flower Garden Banks at comparable
                  depths.
                      Three of the Central Gulf banks are classified as midshelf banks: Sonnier, 29 Fathom,and Fishnet Banks.
                  Because their midshelf location results in lowered light penetration and temperature minimum, the biotic zones
                  do not correspond to the same zones at similar depths on the Flower Gardens. Instead of the high-diversity
                  coral-reef zone found at the Flower Gardens, the midshelf banks at similar depths exhibit the lower diversity
                  Millepora-Sponge Zone. This zone is evident at Sonnier Bank in the Central Gulf. Figure 111-5 depicts the
                  location of Sonnier Bank in relation to the lease blocks and the protective zonation locations in the
                  Topographic Features Stipulation proposed for these proposed sales (Sections II.A.I.c.(l) and II.B.l.c.(l)).









                                                                                  Table 111-4

                                                                    Biotic Zones of Topographic Features
                                                                with Bank Crest and Seafloor Depth in Meters

                                                        Diplora
                                        Millepora-    Montastrea-                                                               Antipatharian-
                                         Sponge         Porites     Madracis   Stephanocoenia    Algal-Sponge Transitional        Nepheloid        seafloor

                Shelf-Edge Banks
                   East Flower Garden                      15            x             x              x               x                 x          100-120
                   West Flower Garden                      20            x             x              x               x                 x          110-130
                   Bright                                                              37             x               x                 x           110
                   MCGrail                                                             45             x               x                 x          110-130
                   Gever                   37                                                         x               x                 x          190-210
                   Rankin                                                                             52              x                 x          110-140
                   Alderdice                                                                          55              x                 x          84-90
                   Rezak                                                                              60              x                 x           120
                   sidner                                                                             55              x                 x           150
                   Ewing                                                                              56              x                 x          85-100
                   Jakkula                                                                            59              x                 x          120-140
                   Bouma                                                                              60              x                 x          90-100
                   Elvers                                                                             60              x                 x           180
                   Parker                                                                             60              x                 x           100
                   MacNeil                                                                            62              x                 x          86-94
                   Sackett                                                                            67              x                 x           100
                   Diaphus                                                                                            73                x          110-130
                   Sweet                                                                              75              x                 x          130-200
                   Appelbaum                                                                          76              x                 x          100-120
                   Phleger                                                                                                              122         200
                Low-Relief
                Kidshelf Banks
                   Claypile                40                                                                                           x           50
                   32 Fathom                                                                                          52                x           55
                   Coffee Lump                                                                                        62                x           70
                Midshelf Banks
                   sonnier                 18                                                                                           x           50
                   Stetson                 20                                                                                           x           60
                   29 Fathom                                                                                          52                x           72
                   Fishnet                                                                                            66                x           78
                Low-Relief
                South Texas Banks
                   Sebree                                                                                                               31          37
                   Big Dunn Bar                                                                                       61                x           67
                   Small Dunn Bar                                                                                     63                x           67
                   Big Adam                                                                                           60                x           64
                   small Adam                                                                                         60                x           66
                   Blackfish                                                                                          60                x          70-74
                   mysterious                                                                                         70                x          74-86
                south Texas Banks
                   Baker                                                                                              56                x          70-74
                   Aransas                                                                                            57                x          70-72
                   southern                                                                                           58                x           80
                   North Hospital                                                                                     58                x          68-70
                   Hospital                                                                                           59                x          70-78
                   south Baker                                                                                        59                x          80-84
                   Dream                                                                                              62                x           80

                sources: Rezak  and Bright, 1981; Rezak et al., 1983.











                            111-48











                                                     -80,884.479'





                                                                            &D
                                                                            q

                                                        283                 q                 284                                  285                                   286






                                                     -95.642.527'


                                                                                                                         3 MILE ZONE




                                                        300                                   299                                  298                                   297




                                                                                                                      1 MILE ZONE
                                                    - 110.400.575'







                                                        303                                   304                                305                                     306
                                                                                        2-3300'




                                                    - 125,158.623'                                                                                                 VERM'LION AREA

                                                                                                                                                                   SOUTH ADDITION





                                                        320                                   319                                  316                                   3. 7









                                                                                                                       NO ACTVATY ZONE
                                                                                              299      /@ 1 @MILZONE
                                                                                            0,304                           3 0 @5@-
                                                                                       2'33@
                                                                                                  9











                            Figure 111-5. Sonnier Bank and Protective Zones as Proposed by the Biological Lease
                                                   .  Stipulation.












                                                                                                                                111-49

                    Of the topographic features depicted in Figure 111-4, 23 are located in the Western Gulf:

                             Shelf-Edee Banks                                  South Texas Banks


                             East Flower Garden Bank                           Big Dunn Bar
                             West Flower Garden Bank                           Small Dunn Bar
                             Geyer Bank                                        Blackfish Ridge
                             Rankin Bank                                       Mysterious Bank
                             Elvers Bank                                       Baker Bank
                             MacNeil Bank                                      Aransas Bank
                             Appelbaum Bank                                    Southern Bank
                                                                               North Hospital Bank
                             Midshelf Banks                                    Hospital Bank
                                                                               South Baker Bank
                             Claypile Lump                                     Dream Bank
                             32 Fathom Bank
                             Coffee Lump
                             Stetson Bank
                             29 Fathom Bank


                    The shelf-edge banks generally exhibit the zonation that is exhibited at the Flower Garden Banks at
                comparable depths. Of interest is Geyer Bank, which crests at 37 in, within the depth that the high-diversity
                coral-reef zone is expected.        However, at this bank, the Millepora-Sponge Zone is evident. The
                Millepora-Sponge Zone is found elsewhere in the Gulf only at the midshelf banks.
                    Three of the midshelf banks contain the Millepora-Sponge Zone: Sonnier Bank in the Central Gulf and
                Stetson and Claypile Banks in the Western Gulf. Claypile Bank, with only 10 ni of relief, is considered a
                low-relief bank and is often enveloped by the nepheloid layer. Thus, the level of development of the
                Millepora-sponge community is lowest at Claypile Bank. Two other midshelf banks in the Western Gulf (32
                Fathom Bank and Coffee Lump) have reliefs less than 10 ni and are considered to be low-relief banks.
                    The South Texas banks are geographically/geologically distinct from the shelf-edge banks. Several of the
                South Texas banks are also low-relief banks. These banks exhibit a reduced biota and have relatively low relief,
                few hard-substrate outcrops, and a thicker sediment cover than the other banks. Sebree Bank is a low-profile
                feature located in 36.5 m (120 ft) of water. The highest area of the bank is about 31 m (102 ft) deep. The
                bank appears composed of large boulders mostly veneered by fine sediments. The low relief of the bank and
                the fine sediments covering the bank indicate that Sebree Bank frequently exists in turbid conditions. The biota
                of the bank appears sparse due to these conditions. Specimens of Oculina diffusa have been located. The
                bank attracts abundant nektonic species including red snapper (Tunnel, 1981).

                3. Terrestrial and Marine Mammals

                a. Marine Mammals

                    This section contains a brief description of the cetaceans of the Gulf of Mexico; more detailed description,
                found in the Final EIS for Sales 131, 135, and 137 (Sections III.B.3.c. and III.BA, pages 111-59 and 111-61), is
                hereby incorporated by reference.

                (1) Nonendangered and Nonthreatened Species

                    Thirty-three species of cetaceans have been identified in the Gulf of Mexico (Table 111-5). By an order
                of magnitude, the bottlenose dolphin is the most common marine mammal in this area. Its distribution and
                movement suggest that there are several distinctive populations in the Gulf. Scott et al. (1989) and Fritts et










                  111-50






                                                                      Table 111-5


                                                       Marine Mammals of the Gulf of Mexico



                           Order Cetacea


                             Suborder Mysticeti (baleen whales)

                               Family Balaenidae
                                  Eubalaena glacialis                    northern right whale                         R*

                               Family Balaenopteridae
                                  Balaenoptera musculus                  blue whale                                   R*
                                  Balaenoptera physalus                  fin whale                                    R*
                                  Balaenoptera borealis                  sei whale                                    R*
                                  Balaenoptera edeni                     Bryde's whale                                R
                                  Balaenoptera acutorostrata             minke whale                                  R
                                  Megaptera novaeangliae                 humpback whale                               R*



                             Suborder Odontoceti (toothed whales)

                               Family Physeteridae
                                  Physeter macrocephalus                 great sperm whale                            C*
                                  Kogia breviceps                        pygmy sperm whale                            C
                                  Kogia simus                            dwarf sperm whale                            U

                               Family Ziphiidae
                                  Mesoplodon bidens                      North Sea beaked whale                       E
                                  Mesoplodon densirostris                Blainville's beaked whale                    R
                                  Mesoplodon europaeus                   Antillian beaked whale                       U
                                  Ziphius cavirostris                    goosebeaked whale                            U











                   C    common, U = uncommon, R = rare, E                extralimital record, I = introduced, Ex = extinct,
                   * = endangered








                       Table 111-5. Marine Mammals of the Gulf of Mexico (continued)                                            111-51

                       Order Cetacen (continued)

                           Family Delphinidae
                              Orcinus orca                           killer whale                                   R
                              Pseudorca crassidens                   false killer whale                             U
                              Feresa attenuata                       pygmy killer whale                             U
                              Globicephala macrorhynchus             short-finned pilot whale                       C
                              Grampus griseus                        grampus/Risso's dolphin                        U
                              Peponocephala electra                  melon-headed whale                             R
                              Tursiops truncatus                     Atlantic bottlenose dolphin                    C
                              Delphinus delphis                      saddleback dophin                              R
                              Steno bredanensis                      rough toothed dolphin                          R
                              Stenella coemleoalba                   striped dolphin                                C
                              Stenella attenuata                     pantropical spotted dolphin                    R
                              Stenella clymene                       short-snouted spinner dolphin                  U
                              Stenella ftontalis                     Atlantic spotted dolphin                       C
                              Stenella longirostris                  long-snouted spinner dolphin                   U



                       Order Carnivora.


                         Suborder Pinnipedia (seals, sea lions)

                           Family Otariidae
                              Zalophus califomianus                  California sea lion                            1, R

                           Family Phocidae
                              Monachus tropicalis                    Caribbean (West Indian) monk seal              Ex



                       Order Sirenia


                           Family Trichechidae
                              INchechus manatus                      West Indian manatee                            C*













             Source: Schmidly and Scarborough, 1990.



             C     common, U = uncommon, R = rare, E = extralimital record, I                    introduced, Ex = extinct,
             *     endangered











                   111-52
                   al. (198,3) noted that the majority of bottlenose dolphin sightings occurred between water d[epths of 18 and 50
                   in (69 and 164 ft). Gruber (1981) and Irvine et al. (1981) noted that highest densities were 1bund near dredged
                   and natural channels. Information on the distribution, abundance, movements, and behavior of the other
                   species is sketchy or nonexistent

                   (2) Endangered and Threatened Species
                       Six endangered cetacean species have been reported in the Gulf of Mexico. They include the sperm, blue,
                   sei, fin, right, and humpback whales. All are uncommon, and only the sperm, fin, and sei whales have been
                   seen in the Central and Western Gulf of Mexico in recent years. Schmidly suggested that the sperm and fin
                   whales have a resident population in the Gulf and that other species are occasional migrants or vagrants
                   (Tucker & Associates, Inc., 1990). Current information on the distribution, abundance, and movements of
                   great whales in the Gulf is sketchy or nonexistent
                       The blue whale (Balaenoptera musculus) is the largest and rarest of the great whales. Historical records
                   suggest that it infrequently passed through the Gulf of Mexico. There have been only two recorded sightings:
                   one off Louisiana in 1924 and another off Texas in 1940. The latter identification is questionable (Schmidly,
                   1981).
                       The fin whale (Balaenoptera physalus), the second largest of the baleen whales, feeds on krill and small
                   schooling fish. Schmidly (1981) reported five strandings and four sightings in the northern Gulf, and the NMFS
                   made several sightings off the Mississippi delta in 1989.
                       Humpback whales (Megaptera novaengliae) are a coastal species and feed primarily on krill and fish.
                   Humpbacks have been sighted in the Central Gulf in 1952 and 1957. They have also been found in the Eastern
                   Gulf near the mouth of Tampa Bay in 1962 and 1983, and near Seahorse Key, Florida, in 1983 (Schmidly, 1981;
                   Gainesville Sun, 1983). There are no records suggesting that the humpback whale was ever more than an
                   infrequent transient in the Gulf.
                       Right whales are the most endangered cetacean in the Western Hemisphere. Their population in the
                   northwestern Atlantic Ocean is estimated at 250-350 individuals. The right whale has rarely been sighted in
                   the Gulf of Mexico, the most recent observations occurring offshore of Brazoria County, Texas, in 1972
                   (Lowery, 1974).
                       Sei whales (Baldenoptera borealis) have been reported from the Gulf in 1956, 197-11, and 1989. They
                   usually travel in groups of two to five individuals. Their population is unknown and they feed on copepods,
                   krill, and small schooling fish.
                       The sperm whale (Physeter macrocephalus), the most abundant great whale in the Gulf of Mexico, has been
                   sighted during all seasons by Fritts et al. (1983) and the DOC (USDOC, NMFS, 1988). Watkins (1977) noted
                   that it inhabits offshore waters deeper than 1,000 in (3,281 ft). In the northern Gulf, it is most frequently
                   sighted along the continental shelf break (Tucker & Associates, Inc., 1990).

                   b. Alabama, Choctawhatchee, and Perdido Key Beach Mice

                       The Alabama, Choctawhatchee, and Perdido Key beach mice, subspecies of the old field mouse
                   (Peromyscuspolionotus), occupy restricted habitats in the mature coastal dunes of Florida and Alabama. Their
                   population has declined as a result of tropical storms and the loss of habitat from coastaldevelopment. Their
                   range is chiefly in Perdido Key State Preserve (Florida), Grayton Beach State Recreational Area (Florida), St
                   Andrews State Recreation Area (Florida), Gulf Islands National Seashore (Alabama), and Gulf State Park
                   (Alabama). Portions of these areas have been designated critical habitat. The beach rnice feed nocturnally
                   on the lee side of the dunes and remain in burrows during the day. Seeds are the major item of their diet
                   (USDOI, FWS, 1987).












                                                                                                                                111-53

              4. Marine Turtles

                  This section contains a brief description of the sea turtles of the Gulf of Mexico; more detailed description,
              found in the Final EIS for Sales 131, 135, and 137 (Section III.B.3.a. and b., pages 111-58 and 111-59), is hereby
              incorporated by reference.
                  The green turtle (Chelonia mydas) population in the Gulf once supported a commercial harvest in Texas
              and Florida, but the population has not completely recovered since the collapse of the fishery around the turn
              of the century. Reports of nesting in the northern Gulf are isolated and infrequent The closest nesting
              aggregations are on the Florida east coast and the Yucatan Peninsula. Green turtles prefer depths of less than
              20 m (66 ft), where seagrasses and algae are plentiful (NRC, 1990).
                  Leatherbacks (Dermochelys coriacea), the most oceanic of the marine turtles, occasionally enter shallow
              water in more northern areas. Their nesting is concentrated on coarse-grain beaches in the tropical latitudes
              (Ogren et al., 1989), but there are rare occurrences on the Panhandle and Flagler County coasts in Florida.
              They feed primarily on jellyfish but also consume crustaceans, fish, and some algae.
                  The hawksbill (Eretmochelys imbficata) is the least commonly reported marine turtle in the Gulf. Texas
              is the only Gulf State where stranded turtles are regularly reported (Ogren et al., 1989), and these tend to be
              either hatchlings or yearlings. Northerly currents may carry them from Mexico, or their nesting range may be
              expanding northward into Texas. They are more frequent in the tropical Atlantic, Gulf of Mexico, and
              Caribbean. Hawksbills prefer reefs and water less than 15 m deep where marine invertebrates are abundant.
                  The Kemp's ridley sea turtle (Lepidochelys kempt) is the most imperiled of the world's marine turtles. The
              population of nesting females has dwindled from an estimated 47,000 in 1947 to less than 1,000 today (NRC,
              1990). An estimated 800 nests are laid annually (NRC, 1990), primarily on a 17-krn (10.5-mi) stretch of beach
              in Rancho Nuevo, Vera Cruz, Mexico (Thompson, 1988). Nesting in the United States occurs infrequently on
              Padre and Mustang Islands in south Texas from May to August (Thompson, 1988). Natural nesting is
              supplemented by a NMFS hatching and rearing program on Padre Island National Seashore. Hatchlings
              appear to disperse offshore to seek refuge in sargassum mats (Collard and Ogren, 1989). The distribution of
              the neritic life stages is associated with the abundance of portunid crabs. Female Kemp's ridleys appear to
              inhabit nearshore areas, and congregations of Kemp's have been recorded off the mouth of the Mississippi
              River (Byles, 1989). Although most Kemp's ridleys inhabit the Gulf of Me3dco, they range along the Atlantic
              Coast to Massachusetts. However, there is speculation that young turtles swept out of the Gulf of Mexico are
              lost to the population (NRC, 1990).
                  The loggerhead sea turtle (Careua caretta) occurs worldwide in depths ranging from estuaries to the
              continental shelf. It has been reported throughout the Atlantic from Newfoundland to Argentina (NRC, 1990).
              Nesting also occurs worldwide. The largest nesting concentration in the United States is on the southeast
              Florida coast from Volusia to Broward Counties (Brook-VanMeter, 1987). In the Gulf of Mexico, recent
              surveys indicate that the Florida Panhandle accounts for approximately one-third of the nesting on the Florida
              Gulf Coast In the Central Gulf, loggerhead nesting has been reported on Gulf Shores and Dauphin Island,
              Alabama; Ship Island, Mississippi; and the Chandeleur Islands, Louisiana. Nesting in Texas occurs primarily
              on North and South Padre Islands, although occurrences are recorded throughout coastal Texas. Hildebrand
              (1982) noted that banks offshore the central Louisiana coast and near the Mississippi Delta are also important
              marine turtle feeding areas. Hatchlings appear to have a pelagic phase followed by a movement inshore and
              associated benthic, omnivorous feeding (Nelson, 1988). Adults are frequently found in association with
              concentrations of portunid crabs.
                  The recently designated Archie Carr National Wildlife Refuge in Brevard and Indian River Counties,
              Florida, hosts the largest concentration of nesting loggerheads and green sea turtles in the United States and
              is the second most important nesting beach for loggerheads in the world.











                   111-54

                   5. Coastal and Marine Birds

                   a. No nkndangered and Nonthmatened Species

                        This section contains a brief description of Gulf coastal and marine birds of the Gulf of Meidco; more
                   detai d, d  scr'ption, hereby incorporated by reference, can be found in the Final EIS for Sales 131, 135, and
                           c   n III.B-5 _, page 111-63).
                            t1o
                   137
                        T                               to oiling either raft at sea, such as gulls and terns, or dive when disturbed,
                         hose birds most suscepti
                   such as cormorants and boobies. The death of coastal area birds caused by OCS-related oil and gas activities
                   makes a strong visual impact that heightens publicity (Clapp et al., 1982a; NRC, 1985).
                        Migrant and nonmigrant coastal and marine birds populate the beaches and wetlands of the northern Gulf
                   of Mexko. This broad category consists of three main groups: waterfowl, wading birds, and marine birds.
                   Feeding habitats include the waters and coastal shores of the open Gulf, bays and estuaries, brackish and
                   freshwater wetlands, as well as coastal farmlands and landfills.
                    -   Waterfowl consist mainly of ducks and geese. The majority of waterfowl found in the northern Gulf of
                   Mexico's coastal wetlands are overwintering migrants. The major waterfowl habitats are brackish and
                   freshwater marshes, but species of resident waterfowl inhabit swamp forests and marshes in all Central and
                   Western Gulf states (Portnoy, 1977; Clapp et al., 1982a and b). Some species feed and congregate in open
                   waters, often clustered in dense rafts. These most commonly include members of the the Pochards
                   (canvasback, redhead, and scaups), sea ducks (bufflehead, goldeneyes, and mergansers), and the ruddy duck
                   (Madge and Burn, 1988). Waterfowl journey to Gulf feeding grounds using specific flight corridors that run the
                   length of the continental U.S. and terminate in distinct localities along the Gulf Coast. Some waterfowl exhibit
                   a limited degree of coastal movement within their terminal locality, but do not cross planning areas (Bellrose,
                   1968).
                      . Wading birds of the coastal Gulf of Mexico consist of herons, egrets and bitterns, storks and cranes, and
                   ibis and spoonbills. They occupy a very diverse array of feeding habitats, and thus demonstrate similarly diverse
                   feeding strategies based on a species' morphology and physiological adaptation in relation to the availibility of
                   prey (Kushlan, 1978). The most abundant species are tricolor herons, snowy egrets, and cattle egrets (Fritts
                   et al., 1983). Texas reported approximately 200,000 wading birds at 387 colony sites in its 1988 colonial
                   waterbird census (Texas Parks and Wildlife Department, 1989). Resident wading bird populations are
                   augmented during the winter by migrants from as far away as southern Canada. The Mississippi Delta divides
                   migrating birds into distinct east-west groups in the Gulf. Migrating adults of each group terminate and remain
                   in distinct localities along the Gulf Coast, while juveniles usually continue migration outside the country.
                   Migration by Eastern Gulf juveniles begins in southern Florida and terminates in the Caribbean or on the
                   Yucatan Peninsula. Juvenile migration in the Western Gulf begins and continues southwestward along the Gulf
                   Coast, terminating in Mexico and Central America (Byrd, 1978; Ogden, 1978; Ryder, 1978). Although their
                   range extends to barrier islands, very few wading birds are seen offshore in the Gulf.
                        Marine birds include both seabirds and shorebirds. Seabirds are defined as those species whose normal
                   habitat and food source is the sea, whether they be coastal, offshore, or pelagic. Within the Gulf of Mexico,
                   this group is composed primarily of gulls and terns, yet also includes some petrels and shearwaters, storm-
                   petrels, tropicbirds, pelicans, gannets and boobies, cormorants, frigatebirds, phalaropes, skuas (jaegers),
                   skimmers, loons, and grebes (Harrison, 1983). Some of these species are entirely pelagic, i.e., both feed and
                   roost offshore, though the majority of seabirds return to shore to roost. Seabirds exploit a wide variety of
                   feeding habitat, and their distribution within marine and coastal ecosystems relates to the distribution of
                   productivity and biomass within these ecosystems (Hunt and Schneider, 1987). Shorebirds are closely associated
                   with coastal and nearshore habitats. Many species are highly migratory and seasonally congregate along select
                   coastal areas, often in great numbers. Within the Gulf of Mexico, this group consists of some oystercatchers;
                   stilts and avocets; plovers; and sandpipers, snipes, and allies (Hayman et al., 1986). In its 1988 colonial
                   waterbird census, Texas reported approximately 300,000 marine birds, of which approximately 115,000 were
                   terns and 137,000 gulls (Texas Parks and Wildlife Department, 1989). Migrants from as far away as the North
                   American Arctic Circle augment resident seabird and shorebird populations during the winter. Some species












                                                                                                                                 111-55

              overwinter in discrete localities within a single planning area of the Gulf of Mexico Region, while other species
              are split into distinct groups east or west of the Mississippi Delta. Some species of marine birds may continue
              migration. Those few species in the Central Gulf that do, migrate nonstop at high altitude from the Mississippi
              Delta to the Yucatan Peninsula and/or northern Central America. Those in the Western Gulf continue
              southwestward along the Gulf Coast to Mexico and Central America, those in the Eastern Gulf to the
              Caribbean. Those that remain on the Gulf Coast exhibit a limited degree of coastal movement within their
              terminal locality, but do not cross planning areas (Clapp, 1982a and b; Fritts et al., 1983).

              b. Endangered and Threatened Species

                   This section contains a brief description of the coastal and marine birds of the Gulf of Mexico; more
              detailed description, found in the Final EIS for Sales 131, 135, and 137 (Sections III.B.3.d.-g., pages 111-59 and
              111-60), is hereby incorporated by reference.
                   The piping plover is endangered in the Great Lakes watershed and threatened elsewhere. Market hunting
              decimated its historic populations, which have remained depressed because of losses to their beach and nesting
              habitat. Habitat loss is primarily the result of damming, channelization, beach armoring, and shoreline
              development (USDOI, FWS, 1988). The plover has three distinct breeding populations: the Atlantic Coast,
              the Great Plains, and the Great Lakes. Only the Great Lakes and Great Plains populations migrate south in
              the fall to winter on the Gulf Coast, in Mexico, and the Caribbean. The Great Lakes population, consisting
              of 17 pairs, is the most depleted; the Great Plains population has 1,258-1,326 pairs (Nicholls, personal comm.,
              1990). On the Gulf Coast, Texas and Louisiana have the largest numbers and highest wintering densities.
              There, the plover prefers intertidal flats and beaches for its habitat. The birds are thought to roost on secluded
              beaches just above the wrack line. Piping plovers are susceptible to contact with spilled oil because of their
              preference for feeding in intertidal areas, a susceptibility documented by the offing of plovers in Texas.
                   The whooping crane breeding population (130 individuals) winters along the Texas coast from November
              to April, occupying the coastal marshes of Aransas, Calhoun, and Matagorda Counties. Portions of these
              counties and all of the Aransas National Wildlife Refuge have been designated as critical habitat for the
              whooping crane. The birds feed on blue crabs and clams in tidal flats (USDOI, FWS, 1986). The conversion
              of wetlands and prairie to agriculture,. and other encroachments by man, have the greatest impact on the
              whooping crane. A rapid recovery of the population is unlikely because of delayed sexual maturity and small
              clutch sizes. Mortality from inclement weather, predation, fire, and collisions with powerlines and aircraft also
              inhibit the birds' recovery.
                   The Arctic peregrine falcon is a subspecies of the peregrine falcon, which breeds in the North American
              tundra. A portion of the population migrates along the Central, Mississippi, and Eastern flyways to winter on
              the U.S. and Mexican Gulf coasts. The birds concentrate along beaches and barrier islands. Their population
              decline has been attributed to reproductive failure resulting from the ingestion of prey containing chlorinated
              hydrocarbons.
                   Bald eagles are found throughout the Gulf States. Bald eagles actively nest in upland and wetland areas
              30-50 mi from the coast throughout the Gulf. Bald eagles inhabit areas near water although they rarely nest
              on the coast. They prey on birds, fish, and small mammals. Nesting occurs in September followed by egg
              laying from October to December. Their population decline is primarily the result of habitat alteration and
              reproductive failure from the ingestion of prey containing chlorinated hydrocarbons.
                   Historically, two nestings have occurred along the Mississippi coast. In northwestern Florida, coastal
              nesting occurs at St Vincent, St Marks, and Lower Suwannee National Wildlife Refuges. Brown pelicans have
              been removed from the Federal endangered species list in Alabama and Florida but remain listed as
              endangered in Mississippi, Louisiana, and Texas. Their decline is primarily the result of hatching failure caused
              by ingestion of fish containing pesticides. Nesting occurs in colonies on coastal islands. Six brown pelican
              rookeries have been documented in Louisiana: on Queen Bess, North, Last, Calumet-Timbalier, and Grand
              Gosier Islands, and at South Pass (Martin, written comm., 1990). There is also a small rookery on Pelican
              Island in Nueces County, Texas. Unsuccessful nesting has occurred on Sunset Island in Matagorda Bay, and
              40 hatchlings have been reintroduced to San Bernard National Wildlife Refuge (USDOI, FWS, 1989). Brown











                   111-56
                   pelicans inhabit the coast, rarely venturing into freshwater or flying more than 32 km (20 mi) offshore. They
                   feed by plunge-diving to catch fish near the surface.

                   6. Fish Resources

                   a. Nonendangered and Nonthreatened Species

                       The Gulf of Mexico supports a great diversity of fish resources that are related to variable ecological
                   factors, such as salinity, primary productivity, bottom type, etc. These factors differ widebr across the Gulf of
                   Mexico and between the inshore and offshore waters. Characteristic fish resources are associated with the
                   various environments and are not randomly distributed.
                       High densities of fish resources are associated with particular habitat types (e.g., east Mississippi Delta
                   area, Florida Big Bend seagrass beds, Florida Middle Ground, mid-outer shelf, and the De Soto Canyon area).
                   Approximately 46 percent of the southeastern United States wetlands and estuaries imporutnt to fish resources
                   are located within the Gulf of Mexico (Mager and Ruebsamen, 1988). Consequently, both finfish and shellfish
                   resources that are estuary-dependent species dominate the fisheries.
                       The life history of estuary-dependent species involves spawning on the continental shelf.; transporting eggs,
                   larvae, or juveniles to the estuarine nursery grounds; growing and maturing in the estuanr-, and migrating of
                   the young adults back to the shelf for spawning. After spawning, the adult individuals generally remain on the
                   continental shelf. Movement of adult estuary-dependent species is essentially onshore-offshore with no
                   extensive east-west or west-east migration.
                       Estuary-related species of importance include menhaden, shrimps, oyster, crabs, and sciaenids. Estuary
                   communities are found from east Texas through Louisiana, Mississippi, Alabama, and northwestern Florida.
                   Darnell et al. (1983) and Darnell and Kleypas (1987) found that the density distribution of fish resources in
                   the Gulf was highest nearshore off the central coast. For all seasons the greatest abundance occurred between
                   Galveston Bay and the Mississippi River. The abundance of fish resources in the far western and eastern Gulf
                   of Mexico is patchy. The high salinity bays of the Western Gulf contain no distinctive species, only a greatly
                   reduced component of the general estuary community found in lower salinities (Darnell et al., 1983). High
                   salinity bays and sounds in the Eastern Gulf contain species amenable to shell, coral sand, and coral silt
                   bottoms. These include pink shrimp, rock shrimp, and stone crab (Darnell and Kleypas 11987).
                       Estuaries of the Gulf of Mexico export considerable quantities of organic material, thereby enriching the
                   adjacent continental shelf areas (Darnell and Soniat, 1979). Populations from the inshore shelf zone (7-14 in)
                   are dominated seasonally by Atlantic croaker, spot, drum, silver seatrout, southern kingfish, and Atlantic
                   threadfin. Populations from the middle shelf zone (27-46 in) include sciaenids, but are dominated by longspine
                   porgies. The blackfin searobin, Mexican searobin, and shoal flounder are dominant on the outer shelf zone
                   (64-110 in).
                       Natural reefs and banks, located mainly between the middle and outer shelf zones support large numbers
                   of grouper, snapper, gag, scamp, and seabass. Reef fish occur on the continental shelf wherever hard/live
                   bottoms with rocks, holes, or crevices are available (USDOC, NOAA, 1986). In the Western and Central Gulf,
                   natural reefs are scattered along the 200-m isobath. Numerous offshore petroleum platforms, believed to act
                   as artificial reefs, augment the hard substrate of natural reefs in this area (Linton, 1988). In the Eastern Gulf,
                   prominent reef complexes such as the Florida Middle Ground provide reef fish habitat (USDOC, NOAA,
                   1986).
                       Hard substrates with some vertical relief act as important landmarks for pelagic species. Coastal pelagics
                   such as mackerels, cobia, bluefish, amberjack, and dolphin move seasonally within the Gulf of Mexico. In
                   spring, king and Spanish mackerels leave their wintering grounds in the southeastern Gulf and move northward
                   along the continental shelf to their spawning and summering areas in the northwestern Gulf (USDOC, NOAA,
                   1986). Their nursery area is probably the shallow portion of the shelf at high nutrient areas near river plumes
                   (Grimes, 1988).
                       Oceanic species such as yellowfin and bluefin tuna are mainly found beyond the continental shelf during
                   winter and spring, but after spawning they move through the Florida Straits into the Atlantic Ocean. Billfishes











                                                                                                                                 111-57

                (black marlin, white marlin, sailfish, and swordfish) spawn in the northeastern Gulf, mostly in areas beyond the
                continental shelf (State of Florida Marine Fisheries, written comm., 1988).
                    Competition between large numbers of fishermen, between fishing operations employing different methods,
                and between commercial and recreational fishermen for a given resource, as well as natural phenomena such
                as weather, hypoxia, and red tides, may reduce standing populations. Fishing techniques such as trawling, gill
                netting, or purse seining, when practiced nonselectively, may reduce the standing stocks of the desired target
                species as well as substantially affect fish resources other than the target Finally, hurricanes may affect fish
                resources by destroying oyster reefs, damaging gear and shore facilities, and changing physical characteristics
                of inshore and ofEshore ecosystems.
                    The majority of fish species in the Gulf of Mexico are believed to be in serious decline from overfishing.
                Continued fishing at the present levels are likely to result in eventual failure of certain fisheries. Standing
                stocks of traditional fisheries such as shrimp and red snapper, and of recent fisheries, such as black drum,
                shark, and tuna, have declined and are thought to be in danger of collapse (Angelovic, written comm., 1989;
                USDOC, NOAA, 1986).
                    The degradation of inshore water quality and loss of Gulf wetlands as nursery areas are considered
                significant threats to fish resources in the Gulf of Mexico (Christmas et al., 1988). Loss of wetland nursery
                areas in the north-central Gulf is believed to be the result of channelization, river control, and subsidence of
                wetlands (Turner and Cahoon, 1987). Loss of wetland nursery areas in the far western and eastern Gulf is
                believed to be the result of urbanization and poor water management practices (Texas Parks and Wildlife,
                written comm., 1989; USEPA, 1989).

                Fit@h

                    Finfish resources are linked both directly and indirectly to the vast estuaries that ring the Gulf of Mexico.
                Finfish are directly dependent when the population relies on low salinity brackish wetlands for most of their
                life history, such as during the maturation and development of larvae and juveniles. Even the offshore
                demersal species are indirectly related to the estuaries because they influence the productivity and food
                availability on the continental shelf (Darnell and Soniat, 1979; Darnell, 1988).
                    Gulf menhaden spawn near the water surface in a localized area of the middle continental shelf proximate
                to the Mississippi River Delta from fall to spring (mid-October through March). Planktonic larvae are
                transported via currents to estuary nursery areas. Larvae enter estuaries when 3-5 weeks old. After the larvae
                grow and transform into juveniles in the shallow portions of the estuary, they move to open and deeper
                estuarine waters. Juvenile and adult Gulf menhaden inhabit estuaries throughout the year (Christmas et al.,
                1982). Some first-year juveniles may overwinter in estuaries. However, most Gulf menhaden move from
                estuaries into offshore marine waters in late fall and winter. There is evidence that older fish move toward
                the Mississippi River Delta (Shaw et al., 1985; Vaughan et al., 1988). Sexual maturation is completed after
                two growing seasons. Immature and spent adult menhaden migrate to estuarine waters from spring to fall
                (April to October). Mature menhaden are sexually inactive in the estuary, but gonads mature for spawning
                in marine waters (Christmas and Waller, 1975).
                    Schooling is apparently an inborn behavioral characteristic beginning at the late larval stage and continuing
                throughout the remainder of life. Their occurrence in dense schools, generally by species of fairly uniform size,
                is an outstanding characteristic that f@cilitates mass production methods of harvesting menhaden. The seasonal
                appearance of large schools of menhaden in the inshore Gulf waters from April to November dictates the
                menhaden fishery (Nelson and Ahrenholz, 1986).
                    Larval menhaden feed on pelagic zooplankton in marine and estuarine waters. Within the estuary, the
                mouthparts of the larvae transform, and juvenile and adult Gulf menhaden become filter-feeding oninivores
                that primarily consume phytoplankton, but also ingest zooplankton, detritus, and bacteria. As filter-feeders,
                menhaden form a basal link in estuarine and marine food webs and, in turn, are prey for many species of larger
                fish (Vaughan et al., 1988).
                    Members of the Sciaenidae family such as croaker, red and black drum, and spotted seatrout have similar
                life histories. Throughout the Gulf, sciaenids have a protracted spawning season over the spring and summer
                or fall and winter. The inception of spawning is variable and dependent on raising or falling water











                  111-58

                  temperatures. There is no consensus on the preferred spawning habitat Large schools of spawning red drum
                  congregate around major passes in relatively shallow water during late summer and fall. Croaker prefer
                  deeper, high salinity waters for spawning. Planktonic larvae develop in nearshore areas and with the help of
                  prevailing currents actively seek protected areas of estuaries and inshore bays with slightly muddy bottoms.
                  Sciaenids move to deeper waters of bays during their first year. After the first year there is gradual movement
                  of sciaenids into the Gulf during cold weather and a pronounced movement back into bays and estuaries in
                  early spring. When mature, older fish move offshore to assemble and spawn. Sexual maturation in seatrout
                  occurs after 5 years and continues until 5 or 6 years of age. Sexual maturation in croaker o4xurs after 5 years
                  and continue for up to 15 years. Sciaenids are opportunistic carnivores whose food habits change with size.
                  Larval sciaenids feed selectively on pelagic zooplankton, especially copepods.             Juveniles feed upon
                  invertebrates, changing to a more piscivorous diet as they mature (Perret et al., 1980; Sutter and McIlwain,
                  1987; USDOC, NOAA, 1986).
                      About 10 percent of finfish in the Gulf of Mexico are not directly dependent on estuaries during their life
                  history. This group can be divided into demersal and pelagic species. Demersal species are associated with
                  live bottoms, reef complexes, hard-bottom banks, and patch reefs. Pelagic species are associated with high-
                  salinity open water beyond the direct influence of coastal systems.
                      Snappers are nonestuary-dependentdemersal fish associated with natural reefs, hard bottom, and artificial
                  reefs of the mid-outer continental shelf. Called reef fish, snappers remain close to underwater structures and
                  exhibit little or no movement. Snappers spawn offshore in groups over unobstructed bottoms adjacent to reef
                  areas. Juvenile snapper form loose aggregates, while adults form schools during the day and disperse at night.
                  Snappers do not migrate or travel away from their reef environment and the surrounding areas. There is a
                  tendency for larger, older snappers to occur in deeper water than juveniles. Seasonal spawning patterns vary
                  among snapper species, but generally, once they attain sexual maturity, they have a protracted spawning period
                  with seasonal peaks. There is a decline in spawning activity among snappers during the winter. Juveniles
                  inhabit shallow nearshore and estuarine waters and are most abundant over sand or mud bottoms. Snappers
                  feed along the bottom on fishes and benthic organisms such as tunicates, crustaceans, and mollusks. Juveniles
                  feed on zooplankton, small fish, crustaceans, and mollusks (Bortone and Williams, 1986; USDOC, NOAA,
                  1986).
                      Coastal pelagics are open-water fish widely distributed throughoutthe Gulf of Mexico. Pelagic species such
                  as king and Spanish mackerel move seasonally in response to water temperature and oceano       'graphic conditions.
                  Mackerels are found from the shore to a 200-m depths. Spanish mackerel frequent the coastal areas while king
                  mackerel stay farther offshore. King mackerel move from the eastern to the north-central and western Gulf
                  in the spring. During cooler fall seasons, they move back into the warmer waters of the southeastern Gulf.
                  A contingent of large solitary adult king mackerel can be found in a localized area of the north-central Gulf
                  during part of the winter. Spanish mackerel spread over the northern Gulf during the summer and are mainly
                  found in southeastern coastal areas in the fall and winter. Mackerels spawn offshore over the continental shelf
                  during the spring and summer. Spawning may occur more than once per season. Juvenile mackerel utilize
                  nearshore areas of high salinity as nurseries. Mackerel feed throughout the water column on other fishes,
                  especially herrings, and on shrimp and squid. Mainly a schooling fish, larger king mackerel occur in small
                  groups or singly (Godcharles and Murphy, 1986; USDOC, NOAA 1986).

                  Shellfish

                      To a greater degree, estuaries determine the shellfish resources of the Gulf of Mexico. Life history
                  strategies are influenced by tides, lunar cycles, maturation state, and estuarine temperature changes. Very few
                  individuals live more than a year, and the majority are less than six months old when they enter the extensive
                  inshore and nearshore fishery. Year-to-year variations in shellfish populations are frequently as high as 100
                  percent and are most often a result of extremes in salinity and temperature during the period of larval
                  development Shellfish resources in the Gulf range from those located only in brackish wetlands to those found
                  mainly in saltmarsh and inshore coastal areas. Life history strategies reflect estuary relationships, ranging from
                  total dependence on primary productivity to opportunistic dependence on benthic organisms. Gulf shellfish











                                                                                                                               111-59

               resources are an important link in the estuary food chain between benthic and pelagic organisms (Darnell et
               al., 1983; Darnell and Kleypas, 1985; Turner and Brody, 1983).
                   A total of nine species of penaeid shrimp utilize the coastal and estuarine areas in the Gulf of Mexico.
               Brown, white, and pink shrimp are the most numerous. Pink shrimp have an almost continuous distribution
               throughout the Gulf but are most numerous on the shell, coral sand, and coral silt bottoms off southern
               Florida. Brown and white shrimp occur in both marine and estuarine habitats and have similar life histories.
               Adult shrimp spawn offshore in high salinity waters; the fertilized eggs become free-swimming larvae. After
               several molts they enter estuarine waters as postlarvae. Wetlands within the estuary offer both a concentrated
               food source and a refuge from predators. After growing into juveniles the shrimp larvae leave the saltmarsh
               to move offshore where they become adults. The timing of immigration and emigration, spatial use of a food-
               rich habitat, and physiological and evolutionary adaptations to tides, temperature , and salinity differ between
               the two species (Muncy, 1984; Turner and Brody, 1983; USDOC, NOAA, 1986).
                   Brown shrimp spawn in shallow offshore marine water in spring and early summer. Postlarval brown
               shrimp move into estuaries from January through June with peaks in early spring. Four to six weeks after
               entering the estuarine nurseries, brown shrimp postlarvae transform into juveniles. Juveniles remain in shallow
               estuarine areas near the marsh-water interface, which provides both feeding habitat and protection from
               predators. With maturation they move into deeper saltmarsh bays and finally to the outer continental shelf
               (Turner and Brody, 1983).
                   White shrimp spawn in shallow nearshore waters from spring to fall. Spawning activity is probably
               correlated with a rapid change in bottom temperature. Recruitment of postlarval white shrimp occurs from
               early summer to fall. Some young white shrimp move from estuaries to nearshore marine waters during late
               fall to overwinter and move back to estuaries in early spring when the water temperatures rise. In nursery
               grounds, juvenile white shrimp move further up waters courses than brown shrimp. White shrimp leave Gulf
               embayments as waters cool from fall through early winter (Muncy, 1984).
                   Active feeding stages of both brown and white shrimp are omnivorous. Larvae feed in the water column
               on both phyto- and zooplankton. After moving into estuarine nursery areas, postlarvae become demersal and
               feed at the vegetation-water interface. Developing larvae ingest the top layer of sediment, which contains
               primarily marsh plant detritus, algae, and microorganisms. When shrimp move to deeper embayments they
               become more predaceous (USDOC, NOAA, 1986).
                   A total of eight species of blue crab utilize the coastal and estuarine areas in the Gulf of Mexico. There
               is only one species, however, that is located throughout the Gulf and comprises a substantial fishery. Bluecrabs
               occur on a variety of bottom types in fresh, estuarine and shallow offshore waters. Spawning grounds are areas
               of high salinity such as saltmarshes and nearshore waters. Spawning occurs from March to November in the
               northern Gulf and year-round in the warmer waters of the southern Gulf. Larval blue crabs occur throughout
               the water column. Movement during the larval stages is governed by tidal action and coastal currents. Female
               blue crabs move into areas of lower salinity to mate, then to higher salinities to spawn. Mature crabs usually
               remain in the same estuary until, after mating, males move into lower salinities as females head for the Gulf.
               During cold periods, blue crabs move into deeper water or burrow into the mud. A benthic omnivore with a
               high degree of variability in food habits, the blue crab feeds on annelids, mollusks, crustaceans, and other
               benthic invertebrates, fishes, carrion, and some detritus (Steele and Perry, 1990).
                   Vast intertidal reefs constructed by sedentary oysters are prominent biologically and physically in estuaries
               of the Gulf of Mexico. Finfishes, crabs, and shrimp are among the animals using the intertidal reefs while they
               are submerged for refuge and also as a source of food, foraging on the many reef-dwelling species. Reefs, as
               they become established, modify tidal currents and this, in turn, affects sedimentary patterns. Further, the reefs
               contribute to the stability of bordering marsh (Kilgen and Dugas, 1989).
                   Oysters spawn from late spring through summer and fall in the Gulf of Mexico. A rapid change in water
               temperature triggers mass spawning over localized areas of reefs. Oysters may spawn several times during a
               season. Oyster larvae are transported throughout estuarine systems by tidal action. After several weeks, free-
               swimming larvae attach in clusters to shell reefs, firm mud/shell bottoms, and other hard substrates. Oysters
               filter-feed principally on small unicellular algae and incidentally on suspended detrital particles (Burrell, 1986).











                   111-60

                   b. Gulf Sturgeon

                       The Gulf sturgeon was accepted as a threatened species for protection under the Endangered Species Act
                   on October 30, 1991. The Gulf sturgeon is a subspecies of the Atlantic sturgeon. It historically spawned in
                   the major rivers of Alabama, Mississippi, and the Florida panhandle. Its present spawning is limited to rivers
                   from the Pearl to the Suwannee Rivers. The largest spawning population occurs in the Suwannee River
                   (Barkulbo,1988). Food-habit studies suggest that the Gulf sturgeon feeds on benthic inveritebrates over sand,
                   hard-bottom, and seagrass substrates. Fish up to 3 years of age inhabit their river of origin or its estuary year-
                   round. Older fish move offshore to feed and return to the river only during the summer. During the riverine
                   stage, adults cease feeding, undergo gonadal maturation, and migrate upstream to spawn. Spawning occurs
                   over coarse substrate in deep holes. The decline of the Gulf sturgeon is due to overflishing and habitat
                   destruction, primarily the damming of coastal rivers and the degradation of water quality.
                   C. OTHER RELEVANT ACTIVITIES AND RESOURC.ES

                   1. OCS Oil and Gas Industry

                       The Gulf of Mexico OCS oil and gas industry has experienced dramatic changes over recent years.
                   "Restructuring of the oil industry has featured centralization of management, finance, and business services,
                   and the use of computer technology to reduce the number of field operating units. The result is streamlined
                   organizations with fewer personnel in regional divisions like New Orleans and exploration         .and production
                   districts like Lafayette, Louisiana." (Baxter, 1990). International and domestic policy is shaping the immediate
                   future of the industry. Domestic policy ramifications include the stringent drilling moratoria on most Federal
                   OCS areas, with the exception of the Central and Western Gulf of Mexico and the Alaska offshore areas, and
                   the future OCS lease sale schedule.
                       Figures 111-6 through 111-8 illustrate the trends in Federal offshore mobile rig utilization, leased Federal
                   OCS acreage, and U.S. hydrocarbon wellhead prices, respectively. These graphs, which cover the period from
                   1974 through the second quarter of 1991, reflect the volatility of the offshore industry from 1981 to mid-1991.
                   While leased acreage appears the most stable of indicators graphed on the figures, the incremental change in
                   leased Federal OCS acreage over thd years would mirror the demand curve associated with mobile rig use.
                       In Fig 1ure 111-6, Mobile Rig Use, the supply curve represents the total number of mobile drilling rigs
                   available in the Gulf of Mexico. The demand curve represents only those rigs working in OCS waters. Federal
                   offshore mobile rig demand decreased significantly between the end of 1981 and mid-1983. In the midst of
                   this decline, however, industry continued to expand its capacity in response to earlier years of growth.
                       Following the institution of the areawide Federal offshore leasing program in mid-1983, the declining oil
                   and gas industry experienced some improvement. The total amount of leased OCS acreage jumped from 11.7
                   million ac (4.7 million ha) in the second quarter of 1983 to 19 million ac (7.7 million ha) in the fourth quarter
                   of 1984. Coincidentally, offshore rig use increased dramatically from mid-1983 through the fourth quarter of
                   1984.
                       By the first quarter of 1 985, the recognition of a continued excess supply of oil and gas worldwide halted
                   the growth of offshore drilling activity in the Gulf of Mexico. Wellhead prices of oil and gas; showed a declining
                   trend throughout 1985, before plummeting to about 50 percent of the 1985 year-end prices by the second
                   quarter of 1986. Despite the continuation of offshore Federal areawide lease sales in the Gulf of Mexico,
                   offshore drilling decreased drastically through 1985 and 1986. The latter quarters of 1987 and early quarters
                   of 1988 saw a steady increase in the demand for mobile rigs in response to the slight upward trend in oil prices
                   at that time. However, offshore mobile rig use in the first two quarters of 1989 once again declined to early
                   1987 levels. This decline was primarily attributed to a prior reduction in the wellhead price of oil. During the
                   latter quarters of 1989 through the earlier part of 1991, mobile rig use has continued to fluctuate, and a sizable
                   gap continues to exist between supply and demand.











                         250



                         200 -           Supply Demand


                  CD
                   jE    150


                  a)
                  E      loo
                  =3
                   Z



                           50




                            0
                                 tK b 4b 4A       Ob C b           Ste (-b tK      Ob A     R@ Cb Z
                                -A, I   'A, )"@%                                   10, ro
                                                                 4) 41 41 @p              45
                               XIOJ XIC
                                                                  Year


               Figure 111-6. Mobile Rig Utilization (USDOI, MMS, 1974-1991a and b).

















                               35


                                                                              Total       Producing     Non-Prod
                                                                                         ------------- ..........................
                               30




                               25




                           M   20
                           S




                                                                                                                                        ............
                               15




                               10


                                                                                                                                 ---------------- -----------
                                                                                                            ----------------------------
                                  5            ............................................. -------------------------
                                                                                            ..........
                                                                               ............................... ..........
                                          ----------



                                  0
                                                                                                                                     m            AZI
                                                                                                                                   Op     4b,    or
                                            .10j,", ,SAO 44A, ,(bA'O ,qAo                               NOY' Nqv NOY' e,                  N     N     N
                                                                                              Year



                Figure 111-7. Leased Acreage (USDOI, MMS, 1974-1991b).










                            35

                            30 -                                                                     Oil      --- Gas
                                                                                               (PER BARREL GAS PRICE BASED
                                                                                                    ON 1 BBL  5.65 Mc@
                            25 -
                      75

                      co
                            20

                      a.
                      L-
                      cz    15

                      0

                            10



                              5



                              0
                                    .A'tK 11b Alb AA                                            (b   (6
                                                                                      !b   tK    @0   @(O   ' ft
                                                                                    C b(b C b(b                     400 C;
                                                                   Cb                                                           @
                                  Nob % Nq " NC b % N, b % N, b N(b N   N    Xq N       N     Nq NC b N       N     N    N     N

                                                                                Year


                  Figure 111-8. Oil and Gas Wellhead Prices (U.S. Dept. of Energy, Environmental Information Administration,
                                1991 a and b).











                   111-64

                        Although there have been fluctuations in mobile rig use and hydrocarbon-wellhead prices, producing leased
                   OCS acreage has increased steadily since 1974. As of the second quarter of 1991, a total of 30.1 million ac
                   (12.2 million ha) were under lease; and approximately 26 percent of this total, 7.8 million ac (3.2 million
                   ha),were producing. The composition of leased acreage has moved seaward during the last decade, with more
                   tracts leased in deep water than ever before.
                        In summary, the current situation is an offshore sector that has a significant capacity in idle equipment,
                   some of which is obsolete, and unemployed labor, some of which lacks the required skills. This idle capacity
                   and the low levels of drilling are expected to continue until the wellhead price of oil and gyas stabilizes.
                        Figures 111-9 and III-10 graphically illustrate the production and production value of oil and natural gas
                   offshore Louisiana and Texas. It is interesting to note that oil and condensate production peaked in 1972
                   at 389.3 MMbbl, while the production value of oil and condensate reached its highest level, $10.2 billion, in
                   1984. Oil and condensate production actually decreased from 1972 to 1980, while the production value
                   increased during that same period. From 1980 to 1985, production increased steadily-, from 1985 to 1988, the
                   production value stabilized somewhat and then decreased. In 1990, both production and the production value
                   of oil increased. Natural gas production in Louisiana and Texas reached its highest level in 1981 at 4,836.3 Bcf;
                   the productionvalue of natural gas peaked in 1984 at $12.7 billion. While the value of gas production declined
                   from 1985 through 1989, the volume of gas production fluctuated during that time period. In 1990, both the
                   production and production value of natural gas increased.

                   2. Socioeconomic Conditions

                   a. Population,. Labor, and Employment

                        The Gulf of Mexico impact area for population, labor, and employment is dermed as that portion of the
                   Gulf of Mexico coastal zone whose social and economic well-being (population, labor, and employment) is
                   directly or indirectly affected by the OCS oil and gas industry. Counties and parishes in the Eastern, Central,
                   and Western Gulf comprise the Gulf of Mexico impact area. However, for purposes of this discussion, the
                   coastal impact area will consist only of those 51 counties and parishes in the Central and Western Gulf of
                   Mexico because the proposed 1993 sales involve the offering of the CPA and WPA. This coastal impact area
                   is displayed on Visual No. 2.
                        The coastal counties and parishes in the impact area extend from Cameron County insouthernmost Texas
                   to Baldwin County in Alabama. Inland counties and parishes are included where offshore oil and gas support
                   activities are known to exist; where offshore-related petroleum industries are established.; and where one or
                   more counties or parishes with a Standard Metropolitan Statistical Area (SMSA) on the coast, to account for
                   all counties and parishes within the SMSA.

                        There are 12 SMSA's in the impact area of the Central and Western Gulf Region:

                                              Central Gulf of Mexico


                            Alabama           - Mobile
                            Mississippi       -   Pascagoula, Biloxi-Gulfport
                            Louisiana         -   New Orleans, Baton Rouge, Lafayette, Lake Charles

                                              Western Gulf of Mexico

                            Texas             -   Beaumont-Port Arthur, Corpus Christi, Houston-Galveston-Brazoria,
                                                  Victoria, Brownsville-Harlingen

                        The most populated SMSA's across the two regions are New Orleans in Louisiana and Houston-Galveston-,
                   Brazoria in Texas. The least populated SMSA's are Pascagoula in Mississippi and Victoria in Texas.













                     1,000



                                     Oil            Gas

                                                 --------------

                      800


                                 (gas barrels based on 1 bbI 5.65 Mcf)
                   CA
                   0  600


                   CO
                   CD

                   as
                      400







                      200







                         0

                                                                            IIq  -CIb I
                                                                       Year


            Figure 111-9. Oil and Gas Production Offshore Louisiana and Texas, 1954 to 1990 (USDOI, MMS, 1984a; preliminary
                         unpublished data through 1990).
















                                      14





                                       12
                                                          Oil                      Gas    ------------

                                W
                                75
                                       10

                                0




                                as
                                0


                                cd
                                        6
                                0
                                4--
                                0


                                W       4


                                0





                                IL


                                        0                               -- --- --- ---- -
                                                     A@                                                             01\11"                          AC?
                                                                                                                                   N7
                                                                                                                   Year


                    Figure III-10. Oil and Gas Production Values Offshore Louisiana and Texas, 1954 to 1990 (USDI, MMS, 198
                                            preliminary unpublished data through 1990).












                                                                                                                                 111-67

                    For planning purposes, the counties and parishes in the impact area are classified in two planning areas:
                the CPA and WPA. Each planning area is subdivided into coastal subareas: C-1 through C-4 in the CPA, and
                W-1 through W-2 in the WPA. The counties and parishes within the planning areas and coastal subareas are
                shown in Figure IV-1.

                A Historical Perspective

                    Table 111-6 lists population and net migration statistics for coastal subareas in the impact area for the years
                1970, 1980 through 1988, and 1990. Strong population growth was experienced in all coastal subareas prior
                to 1983, after which the growth rate declined rather significantly. The statistics on net migration also reveal
                a considerable population outflow during these later years.
                    A study sponsored by the MMS University Initiative Program at the University of New Orleans has
                demonstrated a high correlation between drilling activity in the Gulf of Mexico and net migration (Spain et al.,
                1990). Drilling rig use is a widely used measure of economic activity in the oil and gas industry. Many large-
                scale oil- and gas-related business decisions are made on the basis of drilling activity in the Gulf. In fact, rig
                use is not only considered a barometer for activity in the oil and gas industry, but in other marine industries
                as well (Phillips and James, 1988).
                    As Figure 111-6 shows, drilling rig activity in the Gulf of Mexico took a sharp downturn between the end
                of 1981 and mid-1983. An even greater decline in the demand for mobile drilling rigs was later experienced
                in 1985 and 1986. The population and net migration statistics in Table 111-2 parallel these fluctuations in
                mobile drilling rig activity. Population growth rates for all coastal subareas were relatively high prior to 1983,
                as families moved to the Gulf looking for work in the booming oil and gas industry. As off and gas activity
                began its decline in 1982, drilling rig use also declined, reaching its first low point in 1983. Lower rates of
                population growth accompanied the decline in drilling activity as workers were laid off and left the area in
                search of work elsewhere. After 1983 all subareas experienced several years of net migration outflow. The
                impact on population continued as the demand for mobile rigs declined its steepest from 1984 through 1986,
                to its lowest level in over a decade. Significant net migration out of the region began during the three years
                leading to the 1986 collapse in oil prices. "When oil prices plummeted in 1986, the effects went far beyond
                the energy industry .... Texas lost 230,000 jobs. Louisiana lost 9 percent of its work force, larger than the
                national percentage during the Great Depression" (Washington Post, October 16, 1990).
                    Even though net migration statistics are not available for 1987 through 1990, population growth rates
                during those years seem to reflect net out migration in all coastal subareas. Coastal Subarea C-2, which
                includes several blue-collar oil towns such as Morgan City, experienced a significant population decline in 1987,
                following the 1986 oil price collapse (Baxter, 1990). Population in the Gulf counties of Alabama and
                Mississippi (C-4) do not reflect a high correlation with OCS drilling activity because these States have a much
                lower concentration of oil and gas infrastructure than do Louisiana and Texas.
                    Table 111-7 depicts the historic indicators for the labor force and unemployment in the coastal impact area
                of the Gulf region over the last 30 years. (Because the State of Texas amended its data collection methodology
                and adjusted related historic labor force figures at the county level back to 1980 only, 1970 labor force and
                unemployment indicators are not available for the Western Gulf of Mexico and the Gulf region). In 1970,
                the CPA unemployment rate was about 1.5 percentage points higher than the unemployment rate for the
                United States. By 1980, the unemployment rate for both the Central and Western Gulf of Mexico was below
                the national average. However, with the downturn in oil prices, the trend from 1986 to the present indicates
                an unemployment rate for the Gulf region that surpassed national levels and a labor force growth rate that
                dropped significantly from previous times. Gulf Region population levels have also experienced similar trends
                over this time period.
                    All coastal subareas of the Central Gulf experienced peak levels of unemployment in 1986, followed by
                a slight decline in the labor force between 1986 and 1990. Coastal Subarea C-1, with parishes whose industrial
                make-up is more directly dependent on offshore oil and gas extraction than those of all other coastal subareas,
                experienced the most noticeable decline in labor force, particularly between 1986 and 1988. Coastal Subarea
                C-2, with parishes whose industrial composition is highly dependent on activity indirectly associated with oil and
























                                                                                                                     Table 111-6

                                                                                                    Population Statistics by offshore Subarea-


                                                             1970        1980         1981        1982         1983        1984        1985        1986        1987         1988        1990

                                   Central Planning Area

                                         C-1
                                            Population      363,793    438,786      453f6OO     468,700      476,200    475,100     477,000      476,700     468,900     465,000      461,900
                                            1 Change                      2.1%         3.4%        3.3%        1.6%        -0.24        0.44       -0.1%       -1.611       -0.8%        -0.3%
                                            Net Migration    -2,425      3fO58         7,259       8,627      1,018      -7,084       -3f84O       -5fe6l

                                         c-2
                                            Population      720,341    906,656      935,900     959,600      977,500    984,700     993,200      993,800     984,300     977,100      961,100
                                            % Change                      2.6%         3.2%        2.5%        1.9%         0.7%        0.9%        0.1%       -1.0%        -0.7%        -0.8%
                                            Net Migration      2,081     8,849        13,421      10,651      4,804      -5,657       -4,237     -11,233

                                         C-3
                                            Population    1,071,034   1,213,122   1,234,700   1,254,700    1,267,700   1,269,600   1,273,200   1,275,200    1,262,200   1,248,100    1,105,600
                                            1 change                      1.3%         1.8%        1.6%        1.0%         0.1%        0.31        0.2%       -1.01        -1.1%        -2.5%
                                            Met Migration        749     4,014         6,459       8,052      1,097      -9,764       -7,942       -9,220

                                         C-4
                                            Population      624,735    753,469      762,800     782,000      788,900    792,700     802,600      822,700     827,900     029,100      802,SOO
                                            % Change                      2.1%         1.2%        2.5%        0.94         0.54        1.2%        2.5%         0.6%         0.1%       -1.6%
                                            Net migration    -3,099      5,333         -374       11,547       -656      -3,264         2,956      13,209

                                   Western Planning Area

                                         W-1
                                            Population      577,582    712,633      737,300     767,000      787,700     794,300    800,700      812,300     812,800     806,700      793,200
                                            % Change                      2.3%         3.5%        4.0%        2.7%         0.8%        0.8%        1.4%         0.1%       -0.8%        -0.8%
                                            Net Migration    -9,727      3,930        10,615      18,206      9,184      -4,224       -4,022       1,319

                                         W-2
                                            Population    2,591,896   3,573,398   3,753,200   3,960,200    4,064,600   4,087,400   4,201,600   4,120,900    4,097,300   4,102,200   4,181,900
                                            % Change                      3.8%         5.0%        5.5%        2.6%         0.6%        0.31        0.5%       -0.6%          0.1%         1.0%
                                            Net Migration    29,448      64,468     121,014     153,276       49,530    -30,549     -38,634      -31,987
                                         Notes:  Net Itigration for 1970 is the     annual average over the period 1960-1970.
                                                 Net nigration and % population change for 1960 are annual averages over the period 1970-1980.

                                         -See Figure IV-1.

                                         Sources: Applied Technology Research Corporation, 1990.
                                                    USDOC, Bureau of the Census, 1990.












                                                                                                                           111-69








                                                                Table 111-7

                            Labor rove* and Unemployment Statistics for the Central and Western Gulf Coastal Subareas-
                                                     (average annual data--tbousands)



                                             1970          .1980       1986         1987         1988          1989         1990

          Central Gulf

             C-1
                 Unemployment                 8.8          11.3        33.5         29.6         23.0          15.4         12.3
                 Labor Force                133.1        199.5        219.8        210.8         206.6        206.5        206.2
                 Unemployment  Rate           6.6          5.7         15.2         14.0         11.1           7.5          6.0
             C-2
                 Unemployment                16.2          24.7        61.3         55.0         47.0          33.1         27.8
                 Labor Force                260.8        401.2        457.0        447.8         448.1        447.2        446.5
                 Unemployment  Rate           6.2          6.2         13.4         12.3         10.5           7.4          6.2
             C-3
                 Unemployment                24.3          31.1        63.0         57.7         54.0          40.0         33.5
                 Labor Force                410.9        538.7        584.4        574.0         567.4        566.1        558.1
                 Unemployment  Rate           5.9          5.8         10.8         10.0          9.5           7.1          6.0
             C-4
                 unemployment                11.1          22.7        35.9         34.7         31.0          30.0         25.0
                 Labor Force                216.9        310.6        359.6        359.8         353.7        356.1        355.2
                 Unemployment  Rate           5.2          7.3         10.0          9.7          8.8           8.4          7.0
              Total
                 unemployment                60.4          89.9       193.7        177.0         154.9        118.4         98.6
                 Labor Force              1,021.7     1,449.9       1,620.8      1,592.4      1,575.8      1,375.9       1,565.9
                 Unemployment  Rate           5.9          6.2         12.0         11.1          9.8           7.5          6.3

          Western Gulf

             W-1
                 unemployment               Kh             21.1        45.0         41.6         35.2          31.4         27.8
                 Labor Force                Kh           302.9        347.4        344.9         344.8        347.6        350.0
                 Unemployment  Rate         Kh             7.0         13.0         12.0         10.2           9.0          7.9
             W-2
                 Unemployment               RL             81.0       215.5        190.1         148.9        131.6        115.5
                 Labor Force                M&        1,846.2       2,017.4      2,016.3      2,043.2      2,085.1       2,100.5
                 Unemployment  Rate         MA             4.4         10.7          9.8          7.3           6.3          5.5
              Total
                 unemployment               RL           102.1        260.5        231.7         184.1        163.0        143.3
                 Labor Fore*                MA        2,249.1       2,364.8      2,361.2      2,388.0      2,432.7       2,450.4
                 Unemployment  Rate         MA             4.8         11.0          9.8          7.7           6.7          5.8

          Central and Western Gulf

                 Unemployment               M            192.0        454.2        408.6         339.0        281.4        241.8
                 Labor Force                Kh        3,598.9       3,985.6      3,953.6      3,963.8      4,008.5       4,016.3
                 Unemployment  Rate         MA             5.3         11.4         10.3          8.6           7.0          6.0

          United States

                 Unemployment             3,640.0     7,585.0       8,237.0      7,245.0      6,700.0      6,520.0       6,799.0
                 Labor Force             82,700.0    106,821.0    117,835.0     119,065.0    121,668.0    123,846.0    124,775.0
                 Unemployment  Rate           4.4          7.1           7.0         6.2          5.5           5.3          5.4

          *See Figure IV-1.

          Sources* Alabama Dept.     of Industrial Relations, Research and Statistics, 1990.
                     Louisiana Department of Labor, 1990.
                     Kississippi State Employment Service, 1990.
                     Texas Employment Commission, 1990.











                  111-70

                  gas extraction (e.g., refining and gas processing) and has a high blue-collar involvement, experienced a small
                  decline T labor force during the same time period. The urban and suburban New Orleans composition of
                  coastal Subarea C-3, which has a strong tie to offshore oil and gas development but also a somewhat more
                  diversified economy, experienced a moderate decline in labor force since the downturn in oil prices of 1986.
                  Coastal Subarea C4, consisting of the coastal counties of Mississippi and Alabama, experienced the smallest
                  impact, with only a modest decline in labor force since 1986. The decline observed in the labor force of the
                  Central Gulf coastal subareas is consistent with the net migration experienced in the area aver the same time
                  period, particularly from 1986 to 1988. Thus, the unemployment rate of the Central Gulf impact area has
                  declined steadily from 1986 to 1990.
                      The coastal subareas of the Western Gulf also experienced peak unemployment levels in 1986; however,
                  labor force estimates for the area indicate only a modest decline in 1987. By 1988, the labor force of the
                  Western Gulf impact area was once again on the rise. In fact, the Western Gulf of Mexico experienced an
                  overall increase in labor force from 1986 to the present, in part due to the diversification efforts pursued by
                  the State of Texas. The Western Gulfs unemployment rate has also decreased from its 1986 peak level.
                  Coastal Subarea W-1, consisting of the southern Texas coastal counties, experienced a fairly stable civilian
                  labor force and a strong decrease in unemployment during that time. Coastal Subarea W-2, dominated by the
                  Houston metropolitan area, experienced a significant growth in labor force and a decrease in unemployment
                  since the 1986 downturn in the off and gas industry.

                  Current Statistics

                      Currently, about one-half the United States population resides in coastal areas. The Gulf of Mexico region
                  accounted for 13 percent of that coastal population in 1988 (USDOC, NOAA, 1990). The Central and
                  Western zones of the Gulf Region vary substantially in socioeconomic patterns, ranging from low-density,
                  undeveloped rural areas to high-density, highly developed urban centers.
                      Current population statistics for the coastal impact area are shown in Table 111-6. Coastal Subarea C-3,
                  which includes the New Orleans SMSA, has the greatest level of population in the CPA. Coastal Subarea W-2,
                  which includes the highly populated Houston-Galveston-Brazoria SMSA, has over three times as many
                  inhabitants as C-3.
                      The current population density of counties and parishes in the coastal impact area is displayed in Visual
                  No. 2. According to 1988 statistics, the most densely populated parish in the CPA was Orleans Parish in
                  coastal Subarea C-3. In the Central Gulf, coastal Subarea C-3 had the highest population density at almost
                  425 people per square mile; and C-1 had the lowest, at slightly over 100 people per square mile. In the WPA,
                  Harris County in coastal Subarea W-2, at over 1,600 people per square mile, exhibited thehighest population
                  density during 1988.
                      Table 111-8 reflects the 1987 industrial composition of the coastal subareas. Coastal Subarea C-1, with
                  parishes whose industrial make-up is most directly dependent on offshore oil and gas extraction, had 6.7
                  percent of employment in the mining category, with 88 percent of mining employment related to oil and gas
                  extraction. Services was the largest employer industry for coastal Subarea C-1, accounting for the highest
                  percentage payroll as well.
                      While the service industry was also the largest employer for coastal Subarea C-2, the manufacturing sector
                  contributed the largest percentage payroll. Specifically, the manufacturing sector contributed 14.6 percent of
                  employment and 25 percent of payroll for coastal Subarea C-2 in 1987. Over 14 percent, of manufacturing
                  employment was associated with the standard industrial classifications of petroleum refining, oil field machinery
                  and equipment, pipelines, and gas production and distribution. Mining contributed 2.2 percent of total
                  employment and 2.8 percent of total payroll. In coastal Subarea C-3, the largest employer industry as of 1987
                  was the service industry. Mining contributed almost 3 percent of total employment, but over 6 percent of total
                  payroll.
                      The industry that contributed most significantly to the payroll of coastal Subarea C-4 was manufacturing,
                  accounting for 23.5 percent of total employment for 1987. Over 4 percent of the manufacturing industry was
                  associated with oil and gas activity for that area. Mining played a minor role, contributing less than 1 percent
                  to both employment and payroll.


















                                                                                                           Tabl* 111-9

                                                                       industrial Composition of Central and Western Gulf Coastal Subareas- for 1997

                                                                                                                            Agric. Serv.
                                                                                                           wholesale        For*sty A        Contract                                                Unclassified
                                                     Total     mining    Manufacturing      T*& PeUa        Trade           risheries     Construction Retail Trade                     Services   9stablishatents

                  Central Gulf
                  C-1
                     Employment                  131987.5       87SO.0         16908.5        11235.0          8887.0         703.5           7897.0         33259.0          7942.0      36016.0           359.5
                     Percent in category             100.0         6.7            12.8              8.5          6.7            0.5              6.0             25.2           6.0          27.3             0.3
                     Payroll ($000)             2353002.0      218972.0      4SI122.0        254905.0       196889.0        $229.0         139021.0         318381.0       150872.0      61SIS4.0          6557.0
                     Percent Payroll in cat.         100.0         9.3            19.2            10.$           7.9            0.3              5.9             13.5           6.4          26.3             0.3
                  C-2
                     Employment                  260034.5       S592.0         37953.0        20451.0        17632.0          917.5          30524.0         61849.0        18233.0       65871.0           912.0
                     Percent in category             100.0         2.2            14.6              7.9          6.8            0.4              11.7            23.8           7.0          25.3             0.4
                     Payroll ($000)             4873106.0      135857.0     1219109.0        470648.0       378678.0        10640.0        57751S.0         GS9033.0       349987.0     L058236.0         13403.0
                     Percent Payroll in cat.         100.0         2.6            25.0              9.7          7.8            0.2              11.9            13.5           7.2          21.7             0.3
                  C-3
                     Suployment                  413401.0      12002.0         3726S.0        36636.0        28056.0          931.0          25907.0        103450.0        32959.0      134968.0          1287.0
                     Percent in category             100.0         2.9              9.0             8.9          6.8            0.2              6.3             2S.0           6.0          32.6             0.3
                     Payroll ($000)             76707$3.0      484029.0      93S6S9.0        927936.0       65476S.0        14398.0        514692.0        1067489.0       736303.0     2311644.0         23865.0
                     Percent Payroll in cat.         100.0         6.3            12.2            12.1           8.5            0.2              6.7             13.9           9.6          30.1             0.3
                  C-4
                     Ruployment                  220725.0         390.5        51901.0        L4107.0        13024.0          938.0          15076.0         56322.0        13305.0       54998.0           663.S
                     Percent in category             100.0         0.2            23.5              6.4          5.9            0.4              6.8             25.S           6.0          24.9             0.3
                     Payroll ($000)             3645096.0       IS40.0      1250281.0        295521.0       251337.0        9313.0         249145.0         553231.0       235468.0      7842S9.0          7979.0
                     Percent Payroll in cat.         100.0         0.2            34.3              8.1          6.9            0.3              6.8             15.2           6.5          21.5             0.2

                   Total
                     anployment                 1026229.0      26744.5       144027.S         82629.0        67649.0        3SIO.0           79404.0        2S4820.0        724S9.0      291853.0          3222.0
                     Percent in category             100.0         2.6            14.0              S.0          6.6            0.3              7.7             24.9           7.1          28.4             0.3
                     Payroll ($000)            1654ISS7.0      $47618.0     3856173.0       1948910.0      1471672.0        42SS0.0       1490373.0        2590134.0     1472630.0      4772293.0         S1304.0
                     Percent Payroll in cat.         100.0         4.6            20.8            10.5           7.9            0.2              8.0             14.0           7.9          25.7             0.3

                  Western Gulf
                  W-1
                     suployment                  190880.0       5622.0         26194.5        11939.0        13017.0        1197.S           137SO.0         53061.5        12413.0       52931.5           764.0
                     Percent in category             100.0         2.9            13.7              6.3          6.8            0.6              7.2             27.8           6.3          27.7             0.4
                     Payroll ($000)             2792111.0      141430.0      613320.0        2857$3.0        24813.0        17127.0        219904.0         515969.0       220758.0      737730.0         15177.0
                     Percent Payroll in cat.         100.0         5.1            22.0            10.2           0.9            0.6              7.9             18.5           7.9          26.4             0.5
                  W-2
                     employment                 1461021.0      47290.S       212953.0        115337.5       112490.0        7997.0         12686S.0         305724.0       119413.0      408319.0          4629.0
                     percent in category             100.0         3.2            14.6              7.9          7.7            0.5              8.7             20.9           8.2          27.9             0.3
                     Payroll ($000)            32SS7637.0    1897650.0      6766402.0       316L667.0      3265425.0       114977.0       2713398.0        3410756.0     3115982.0      2119757.0         91423.0
                     Percent Payroll in cat.         100.0         5.8            20.8              9.7          9.7            0.4              8.3             10.5           9.6          24.9             0.3

                  Total
                     amployment                 1651901.0      52912.5       239147.5        127276.5       125507.0        9184.S         140618.0         3S4785.5       131926.0      461250.5          5393.0
                     Percent in category             100.0         3.2            14.5              7.7          7.6            0.6              0.5             21.7           8.0          27.9             0.3
                     Payroll ($000)            35349748.0    2039080.0      7379922.0       3447450.0      3190238.0       132104.0       2933202.0        3924725.0     3336740.0      $957497.0         106200.0
                     Percent Payroll in cat.         100.0         S.8            20.9              9.0          9.0            0.4              8.3             11.1           9.4          25.1             0.3

                  Central and western Gulf
                     amploy'sent                2678129.0      79477.0       383173.0        20970S.5       193L54.0        12494.5        220022.0         613665.5       204315.0      733103.3          8615.0
                     Percent in category             100.0         3.0            14.3              7.8          7.2            0.5              8.2             22.9           7.6          28.1             0.3
                     Pyroll ($000)             53891735.0    2886498.0      11236095.0      5396360.0      46619LO.0       174694.0       4413575.0        6524359.0     4909370.0      13629780.0        158604.0
                     P:rcont Payroll in cat.         100.0         S.4            20.8            10.0           0.7            0.3              8.2             12.1           8.91         25.3             0.3

               *Sao rigure IV-1.
               Sources USDOX, M5 analysis of data from USDOC, Bureau of the Census, 1989.











                  111-72

                      The 1987 industrial composition for the Western Gulf of Mexico coastal subareas--W4 and W-2--was
                  remarkably similar. In both coastal subareas the largest employer industries for 1987 were services and retail
                  trade. The industries providing the largest payroll were services and manufacturing. Manufacturing
                  employment related to oil and gas activity in W-1 accounted for almost 11 percent of aR manufacturing
                  employm6nt in the area. About 5 percent of all employment for coastal Subarea W-2 in 1987 can be directly
                  or indirecItly attributed to the off and gas extraction industry.
                      The Gulf area in 1990 reflects a modest to significant recovery from the high unemployment levels
                  experienced after the 1986 downturn of the oil and gas industry. Ironically, the Gulf Coast is experiencing a
                  shortage of skilled labor in the oil and gas industry due to "the restructuring of the oil industry to centralize
                  management, finance, and business services, and the use of computer technology" (Baxter, 1930). The Central
                  Gulf of Mexico's unemployment rate of 6.3 percent is still somewhat over the national average. Of an coastal
                  subareas in the Gulf, coastal Subarea W-1 experienced the highest unemployment rate through July 1990, but
                  that rate stiff exhibited a marked improvement from earlier 1986 levels. Coastal Subarea W-2, also in the
                  Western Gulf, exhibited the lowest. unemployment rate for 1990, only 0.1 percentage points higher than the
                  national average.
                      In relation to oil and gas activity in the Gulf of Mexico, the exploration and production of crude oil and
                  gas is classified as a primary industry. Classified as secondary industries are activities associated with the
                  processing of crude oil and gas in refineries, natural gas plants, and petrochemical plants. While detailed
                  employment information strictly related to offshore activity in the Gulf of Mexico is not readily available, data
                  for selected Standard Industrial Classification (SIC) codes from the annual U.S. Bureau of the Census County
                  Business Patterns can be used to estimate such employment and related economic effects on the coastal region.
                  The results of the most recent MMS Gulf of Mexico OCS Region offshore-employment analysis, using 1987
                  data from the latest issue of County Business Patterns, are discussed in the following paragraph.
                      The specific SIC codes used in the analysis include the following:

                                            13       -       oil and gas extraction
                                            29       -       petroleum and coal products
                                            3533     -       oil field machinery
                                            46       -       petroleum pipelines
                                            492      -       gas production distribution
                                            517      -       petroleum and petroleum products

                      These SIC codes can be used to further identify the extent of direct and indirect employment in the oil and
                  gas industry. SIC 13, which is the code that includes crude oil and gas production, is the primary industry from
                  which direct-employment estimates are obtained. The other codes listed identify secondary industries that form
                  the base for estimating indirect employment. Excluded from this analysis are some SIC codes that include
                  OCS-related industries within broader categories of data (i.e., SIC 3731 includes shipbuilding and mobile rig
                  fabrication). Finally, numerous tertiary industries are not shown above but are affected by both direct and
                  secondary industry employment. Induced employment resulting from such tertiary industry activity, however,
                  is included in the calculation of OCS Program employment.
                      The production of OCS oil and gas, particularly offshore Louisiana, has been a major source of revenue
                  in the study area since 1954. Data from the 1987 Census show that the average annual payroll associated with
                  oil and gas activities amounts to approximately $2.2 billion for the Gulf of Mexico Region ($1.7 billion for the
                  Central Gulf, $0.6 billion for the Western Gulf, and $2.2 million for the Eastern Gulf). Average annual tax
                  dollars generated per employee in the offshore oil and gas program are estimated at 8 percent of payroll
                  revenues. Thus, State and local taxes generated annually by the Federal offshore oil and gas program are
                  estimated at $134.7 million from the Central Gulf, $44.3 million from the Western Gulf, and $0.2 million from
                  the Eastern Gulf.
                      Job estimates as of June 1991 show that 83,400 jobs are directly or indirectly dependent on the offshore
                  program. Approximately 80 percent of these jobs are associated with activity in the CAntral Gulf and 20
                  percent are related to the Western Gulf. Nearly all offshore-related employment in the Central Gulf is due
                  to activity offshore Louisiana; in addition, offshore activity in other areas of the Gulf also generates












                                                                                                                                 111-73

                employment in Louisiana. Estimates of direct employment offshore are 30,000 workers in the Central Gulf,
                and 7,500 workers in the Western Gulf.

                Projections

                    Table 111-9 contains population and employment projections for the coastal subareas of the Central and
                Western Gulf impact area. Projections for 1991 through 2010 are based on a population forecast made by
                National Planning Association Data Services, Inc. (NPA), an economic forecasting firm located in Washington,
                D.C. (NPA Data Services, Inc., 1991). Projections through the year 2027 were extrapolated from NPA!s county
                level population growth rates for the later years of their forecast.
                    Regionally, growth is expected to continue to be relatively stronger in the South and West of the United
                States (NPA Data Services, Inc., 1991) As coastal population in the South continues to grow, the quality of
                living standards that initially attracted residents to the area will likely diminish. The population of counties and
                parishes in the Central and Western Gulf impact area is expected to increase approximately 20 percent from
                1990 population levels by the year 2010. The Gulf of Mexico Region is one of the less densely populated
                coastal regions in the country, second only to the Pacific Region, which includes Alaska's vast territory. The
                population density of coastal Texas has historically been the highest in the region and is expected to continue
                ahead of other Gulf Coast States in this respect Louisiana and Mississippi are expected to continue
                experiencing steady population growth through the year 2010. Alabama, which was once as densely populated
                as coastal Texas, is expected to have the lowest population density of states in the Gulf of Mexico Region by
                2010.
                    Projections by NPA of "Hot Spots" for population growth in the Gulf of Mexico region include several
                counties and parishes in Texas and Louisiana. Harris County, Texas, leads the Gulf Region in net population
                change by the year 2010, with a projected increase of nearly 900,000--approximately one-third of the county's
                current population. Fort Bend and Montgomery Counties, which neighbor the Houston area, are also expected
                to exhibit high population growth rates. In Louisiana, East Baton Rouge and Jefferson Parish are projected
                to add about 79,000 and 67,000 persons to their current population counts, respectively.
                    Table 111-9 also provides employment projections for the coastal subareas of the Central and Western Gulf.
                The largest employment increase in the Gulf Region is expected in Harris County, Texas (coastal Subarea W-
                2), which is projected to add approximately 752,000 employees by the year 2010. In Louisiana, both Jefferson
                Parish (coastal Subarea C-3) and East Baton Rouge Parish (coastal Subarea C-2) are anticipated to experience
                sizeable increases in employment levels. By the year 2027, the largest employers will continue to be coastal
                Subarea W-2 in the WPA and coastal Subarea C-3 in the CPA. Because these baseline projections assume
                the continuation of existing social, economic, and technological trends, they also include employment resulting
                from the continuation of current patterns in OCS leasing activity.

                b. Public Services and Infrastructure

                    Public services and infrastructure, as used here, include commonly provided public, semi-public, and private
                services and facilities, such as education, police and fire protection, sewage treatment, solid-waste disposal,
                water supply, recreation, transportation, health care, other utilities, and housing. The geographic area that
                could be directly affected by the proposals include coastal parishes and counties in the Central and Western
                Gulf of Mexico.











                   111-74







                                                                    Table 111-9

                       Population and Employment Projections for the Central and Western Gulf Coastal Subareas*

                                                    1990       1991         1992        1995         2000         2010           2027

                 Central Planning Area

                       C-1
                               Population      461,908      462,861      465,856     474,956      489,544      516,207      564,909
                               % Growth                        0.21%        0.65%       0.65%        0.61%        0.53%        0.53%
                               Employment      240,032      237,622      242,009     255,663      274,405      30:2,675     357,578
                               % Growth                       -1.00%        1.85%       1.85%        1.42%        0.99%        0.99%


                       C-2
                               Population      961,127      966,286      977,572     1012,229     1059,78      1142,073     1296,901
                               % Growth                        0.54%        1.17%       1.17%        0.92%        0.75%        0.75%
                               Employment      457,709      451,778      460,964     489,658      527,104      583,188      692,563
                               % Growth                       -1.30%        2.03%       2.03%        1.48%        1.02%        1.02%

                       C-3
                               Population    1,185,552    1,182,956   1,186,429    1,196,909     1,220,673        1,282   1,393,410
                               % Growth                       -0.22%        0.29%       0.29%        0.39%        0.49%        0.49%
                               Employment      638,991      628,053      637,035     663,245      705,263      781,893      931,753
                               % Growth                       -1.64%        1.35%       1.35%        1.24%        1.04%        1.04%


                       C-4
                               Population      802,474      795,929      800,084     812,678      840,683      888,337      975,630
                               % Growth                       -0.82%        0.52%       0.52%        0.68%        0.55%        0.55%
                               Employment      389,003      383,948      389,759     407,723      432,354      471,115      545,149
                               % Growth                       -1.31%        1.51%       1.51%        1.18%        0.86%        0.86%

                       Total
                               Population    3,411,061    3,408,032   3,429,941    3,496,772     3,610,680    3,828,617   4,230,849
                               % Growth                       -0.09%        0.64%       0.65%        0.64%        0.59%        0.59%
                               Employment    1,725,762    1,701,878   1,729,766    1,816,289     1,939,126    2,138,871   2,527,043
                               % Growth                       -1.38%        1.64%       1.64%        1.32%        0.99%        0.99%

                 Western Planning Area


                       W-1
                               Population      793,178      764,844      764,333     762,801      793,549      851,257      959,154
                               % Growth                       -3.57%       -0.07%      -0.07%        0.79%       0.70%         0.70%
                               Employment      346,498      341,686      347,675     366,279      392,264      434,554      517,172
                               % Growth                       -1.39%        1.75%       1.75%        1.38%       1.03%         1.03%

                       W-2
                               Population    4,181,915    4,261,973   4,339,436    4,580,377   4,907,483     5,480,708    6,613,008
                               % Growth                        1.91%        1.82%       1.82%        1.39%       1.11%         1.11%
                               Employment    2,300,203    2,291,671   2,349,323    2,531,129   2,800,245      3,246,055   4,174,519
                               % Growth                       -0.37%        2.52%       2.52%        2.04%       1.49%         1.49%


                       Total
                               Population    4,975,093    5,026,817   5,103,769    5,343,178   5,701,032     6,331,965    7,572,162
                               % Growth                        1.04%        1.53%       1.54%        1.31%       1.06%         1.06%
                               Employment    2,646,701    2,633,357   2,696,998    2,897,408   3,192,509     3,681,104    4,691,690
                               % Growth                       -0.50%        2.42%       2.42%        1.96%       1.44%         1.44%


                               * See Figure IV-1.

                               Source: NPA Data Services, Inc., 1991.











                                                                                                                                    111-75

                     Infrastructure and public service development in the area of consideration have tracked population growth
                and community development Population changes in the area are discussed in Section III.C.2.a. The Gulf
                Coast physiography has strongly influenced population distribution and community growth. Much of the land
                in the area is low and characterized by a water table at or near the surface for much of the year. The
                Louisiana coastal area includes broad expanses of coastal marshes and swamps interspersed with ridges of
                higher, well-drained land along the courses of modern and extinct river systems. Most of the larger urban
                centers in coastal Louisiana are located along major navigable rivers and/or along the landward edge of the
                coastal zone (i.e., Lafayette and Lake Charles). To a lesser extent, this pattern continues into Texas where
                urban centers such as Houston and Beaumont are located at the heads of navigation of estuaries. In
                Mississippi and Alabama, much of the population resides along the immediate coastal fringe and along the
                shores of navigable estuaries between Gulfport, Mississippi, and Mobile, Alabama.
                     The characteristics of the regional landscape have promoted the growth of population centers keyed to the
                development of natural resources that occur in the area (oil and gas and other minerals) or to agricultural,
                forestry, and fisheries resources suited to the regional land and climatic conditions. Rice and sugar cane have
                become primary crops planted along the coast, sometimes associated with crawfish aquaculture. Forestry has
                long been an important activity along the coast, in earlier days using swamp and riparian hardwoods, and today
                mainly pine plantations. The abundant fisheries resources of the open Gulf and nearshore waters have
                promoted a large fishing fleet and associated seafood processing facilities. The most important resource that
                has affected community infrastructure changes in the Gulf area, however, has been oil and gas development,
                both within State jurisdiction and on the Federal OCS.
                     The area's natural resource-based economy has influenced the development of the particulars of the
                infrastructure distribution in the area. One interstate highway (1-10) traverses the area along the inner margin
                of the coastal zone. For the most part, only secondary highways penetrate longitudinally into the coastal areas.
                A similar pattern applies to railroads. The agricultural, forestry, and mineral products exported from the area
                could be largely shipped in bulk by water transport, pipeline, or spur raft line, and an elaborate network of
                improved highways was not needed. Similarly, most communities are scattered throughout the region and are
                based on extracting, growing, or processing area resources.
                     Public services and infrastructure depend heavily on levels of population and employment. Population
                growth and migration patterns in the area have affected the infrastructure and public service institutions in the
                area. The most important factor in this regard has been the oil and gas industry, particularly in Louisiana and
                Texas. Oil and gas production began on land and in nearshore waters.
                     Cumulative production from the Louisiana coastal areas from 1954 through 1982 exceeded production from
                the Gulf of Mexico Federal OCS by 72 percent for oil and condensate and by approximately 50 percent for
                gas production. Annual production from the State coastal area consistently exceeded production from the OCS
                until 1974 (USDOI, MMS, 1984b). Since 1974, however, the hydrocarbon production from the Gulf of Mexico
                OCS has surpassed onshore and nearshore coastal production. The northern Gulf of Mexico OCS has yielded
                9-12 percent of the crude oil and 10-20 percent of the natural gas produced in the United States from 1973
                to 1981. By 1981, the northern Gulf of Mexico was the most developed offshore area in the world (Gramling
                and Freudenburg, 1990).
                     Following years of relatively stable prices, the average annual price of oil began to rise in 1973, initially in
                response to the Arab Oil Embargo and later as a result of the increasing marketing effectiveness of the
                Organization for Petroleum Exporting Countries (OPEC). The price increase stimulated off and gas
                exploration on the OCS, and with the increase in OCS oil and gas exploration and development came a
                concomitant increase in population in the coastal parishes and counties of the Central and Western Gulf of
                Mexico, due, in part, to in-migration. Therefore, it is assumed that the in-migration to the subareas is due, in
                large part, to the increase in oil and gas activity resulting from the increase in the world oil price.
                     According to Table 111-6, the average annual percent of population change in the Central Gulf subareas
                (C-1, C-2, C-3, and C4) from 1970 to 1980 was between 1.3 and 2.6 percent. Average annual net migration
                into the subareas at the same time was between 3,058 and 8,849. The population increase in Western Gulf
                subareas (W-1 and W-2) mirrored those of the Central Gulf. The average annual percent of population change
                in the Western Gulf subareas from 1970 to 1980 was between 2.3 and 3.8 percent. Average annual net
                migration into the subareas at the same time was between 3,930 and 64,468.











                  111-76

                      In 1981, 1982, and 1983 most of the Central Gulf subareas experienced population increases. The sole
                  exception to this was Subarea C-4, which experienced net out-migration in 1981 and in 1983. Percent change
                  in popul@tion over these years varied from 0.9 percent to 3.4 percent The greatest percent change in
                  populati6n occurred in Subarea C-1 in 1981. In the Western Gulf, as in the Central Gulf, population continued
                  to increase from 1981 to 1983. The percent change in population in the two subareas ranged from 2.6 to 5.5
                  percent Average annual net migration into these areas was between 9,184 and 153,276. The greatest
                  population increase occurred in Subarea W-2 in 1982.
                      Cyclic fluctuation as it relates to oil and gas development in the Gulf of Mexico has been commented on
                  by Gramling and Freudenburg (1990), Gramling and Brabant (1986), and Gramling (1984). The rural and
                  relatively isolated nature of the coastal parishes in Louisiana meant that increases in population resulted in
                  greater responsibilities for public service agencies and a need for improved infrastructure in these parishes.
                      The rapid increase in population was associated with an increase in the demand for housing and public
                  services. There was also a strain on transportation networks caused by the population increase and by the need
                  for offshore workers and supplies to reach offshore activity staging areas.
                      The downturn in world oil prices that characterized the mid-1980's was reflected in a decreasing amount
                  of oil and gas activity in the Central and Western Gulf, which, in turn, resulted in greater unemployment and
                  underemployment in the coastal parishes and counties. During the downturn, public and pri%vate public service
                  agencies were called upon to provide families and individuals with food, shelter, and other forms of assistance.
                  High unemployment rates and net out-migration from the area during much of the 1980's resulted in falling
                  real estate values and financial problems for individuals and financial institutions. State and local agencies also
                  experienced difficulties in supporting and continuing those programs for upgrading infrastructure that had been
                  started or planned during the earlier days of oil and gas industry expansion.
                      It may be seem that, as a response to fluctuations in the world oil price, the Central and Western Gulf
                  coastal subareas experienced an extended period of high oil and gas activity followed by a period of diminished
                  activity. (The Eastern Gulf coastal subareas have seen minimal oil and gas activity in the same period.) It
                  should be noted that the oil and gas activity has occurred within both federally and State-regulated areas. In-
                  migration of persons seeking employment occurred in the coastal parishes and counties of the Central and
                  Western Gulf during the period of high oil and gas activity-, out-migration occurred from most of the same
                  areas during the downturn. As noted above, the Gulf area in 1990 reflects, at a minimum, a modest recovery
                  from the high unemployment levels experienced after the downturn.

                  c. Social Patterns

                      The area that could be affected by the proposed action includes coastal parishes and counties in the
                  Central and Western Gulf of Mexico (Section III.C.2.a.). The analysis area has been defined as those parishes
                  or counties that are expected to be directly impacted by the proposal.
                      The Spanish, in the 16th and 17th centuries, were the earliest European explorers of the Gulf of Mexico.
                  They discovered a population of Native Americans ranging from settled, agricultural chiefdoms to nomadic
                  hunter-gatherers. Historic development along the northern Gulf of Mexico was associated with ports
                  established by the Spanish and French. The Spanish developed Pensacola in 1698, the French Biloxi (1699),
                  Dauphin Island (1699), Mobile Bay (1701), and New Orleans (1717). With the end of the Colonial period and
                  the Texas Revolution, the number of ports along the northern Gulf of Mexico increased. Ports such as Tampa,
                  Brownsville, Key West, and Pascagoula were founded in the 19th century (cf. Garrison etal., 1989).
                      The Native American cultures, with few notable exceptions (cf. Peterson, 1987), -were absorbed or
                  destroyed by the early 20th century. Remnants of the earlier, European cultures were found primarily in
                  isolated areas along the Gulf margin. The Acadians, located in southwest Louisiana, were descendants of
                  French-speaking Acadians displaced from the East Coast of Canada in 1755. The presence of French-speaking
                  Louisiana to the south served to attract many of these people (now known as Cajuns). A roughly triangular
                  area with the Mississippi Delta to the east; Alexandria, Louisiana, to the north; and Lake Charles, Louisiana,
                  to the west is now known as the French Triangle (Rushton, 1979). Other isolated remnant cultures, such as
                  the Islefios from the Canary Islands in St. Bernard Parish, Louisiana (cf, Guillot, 1980); Greeks in Tarpon












                                                                                                                                 111-77

                Springs, Florida; Dalmation Coast Yugoslavs in the delta of the Mississippi River; and Oriental immigrants in
                the southeast portion of Louisiana existed along the Gulf rim margin (Spitzer, 1987; Cohen, 1984). With the
                exception of the Orientals in southeast Louisiana, all of the above cultural enclaves are recognizable today.
                    Traditional occupations in the Gulf coastal parishes and counties include trapping and fishing. Louisiana
                produces more fur-bearing mammals from trapping than any other state in the country. A 10-year average
                (1976-1977 through 1985-1986 seasons) of comparative takes of fur animals in Louisiana reveals an average
                worth of $11,594,905.06 of pelts and meats (Calhoun, 1988). Traditionally, trappers and their families would
                enter the marsh in autumn and spend the fall and winter trapping. Today, many trappers run their traplines
                as a daily routine from their homes at the edge of the marsh (Hallowell, 1979). Trapping was usually practiced
                in association with other resource gathering activities, such as shrimping. These activities occurred as a
                seasonal round, with the trapper or shrimper sometimes spending time away from the family in pursuit of the
                resource.
                    Today, the Gulf of Mexico provides nearly 40 percent of the commercial fish landings in the continental
                U.S. Species that are commercially fished in the Central and Western Gulf include menhaden, shrimp, oyster,
                and blue crab. Traditional fisheries occupations may involve exploitation of the coastal marshes and bays as
                well as exploitation of offshore species. The fishermen frequently spend days or weeks at a time in pursuit of
                the resource, coming back to dock only to unload and take on fuel and provisions.
                    Other traditional occupations along the Gulf Coast, such as the gathering of Spanish moss in the coastal
                parishes of Louisiana and sponge diving off the coast of Florida, have diminished or disappeared as resources
                were diminished or depleted and preferred alternatives were developed.
                    Farming of sugarcane, rice, and other crops has also been a traditional occupation in the coastal subareas
                of the Gulf. Major crops produced in southwestern Louisiana include rice and soybeans. South-central
                Louisiana is the State's major sugarcane-producingarea. Around the Mississippi River delta region, vegetables
                and fruit are grown for consumption. In recent years, rice farming has frequently been combined with crawfish
                aquaculture. Other forms of aquaculture occurring in the coastal subareas of the Central and Western Gulf
                include alligator, catfish, and some saltwater species (red drum).
                    The exploration and development of oil and gas resources have occurred in the coastal parishes and
                counties of the Central and Western Gulf for the greater part of a century (Brantly, 1971). It can be argued
                that, after so long a period time, work in the oil and gas industry has become one of the traditional occupations
                of the coastal subareas in the Central and Western Gulf. The work scheduling associated with employment
                in the OCS oil and gas industry generally requires blocks of time at the location, followed by a block of time
                off. Differing schedules include seven days on followed by seven days off, two weeks on and two weeks off,
                and other variations on the theme. This work schedule allows for the part-time pursuit of the traditional
                occupations of trapping and fishing in the extended periods of off time.

                3. Commercial Fisheries

                    The Gulf of Mexico continues to provide nearly 38 percent of the commercial fish landings in the
                continental United States. During 1990, commercial landings of all fisheries in the Gulf totaled nearly 1.6
                billion pounds, valued at about $640 million (USDOC, NMFS, 199ITablea).
                    Menhaden,with landings of 1.1 billion pounds,valued at $54.4 million, was the most important Gulf species
                in quantity landed during 1990. Shrimp, with landings of 249.5 million pounds, valued at $391 million, was the
                most important Gulf species in value landed during 1990 (USDOC, NMFS, 1991a). The 1990 Gulf oyster
                fishery accounted for 36 percent of the national total with landings of 10.6 million pounds of meats, valued at
                about $34 million. Ile Gulf blue crab fishery accounted for 18 percent of the national total with landings of
                45.5 million pounds, valued at $17 million (USDOC, NMFS, 1991a).
                    Alabama ranked last among Central and Western Gulf states in total commercial landings for 1990 with
                23 million pounds landed, valued at $36 million. Shrimp was the most important fishery landed, with 14.9
                million pounds, valued at $30.9 million. In addition, during 1990, the following six species each accounted for
                landings valued at over $125,000: blue crab, shark, black mullet, red snapper, flounder, and the American











                  111-78

                  oyster (USDOC, NMFS, 1991a). Alabama had about 4,000 commercial saltwater, licensed fishermen during
                  1990 (1.4zauski, written comm., 1990).
                      Mississippi ranked second among Central and Western Gulf states in total commercial fishery landings for
                  1990, with 319.5 million pounds landed, valued at $42 million. Shrimp was the most impo@rtant fishery, with
                  15.2 million pounds landed, valued at about $25.7 million. Menhaden landings were significant during 1990,
                  with 275  million pounds landed, valued at $11.7 million. In addition, during 1989, the following four species
                  each accounted for landings valued at over $200,000- red snapper, Vermilion snapper, American oyster, and
                  black mullet (USDOC, NMFS, 1991a). In 1990, Mississippi had about 3,500 commercial saltwater, licensed
                  fishermeh (Quinn, written comm., 1990).
                      Loui 'siana ranked first among Central and Western Gulf states in total commercial fishery landings for 1990,
                  with nearly 1.1 billion pounds landed, valued at $263 million. Menhaden was the highest quantity finfish, with
                  866 million pounds landed, valued at $41.7 million. Shrimp was the highest value shellfish, with 119.5 million
                  pounds landed, valued at $153 million. In addition, during 1990, the following nine species each accounted for
                  landings valued at over $1 million: black drum, red mullet roe, shark, red snapper, vermilion snapper, bluefin
                  tuna, yellowfin tuna, blue crab, and the American oyster (USDOC, NMF`S, 1991a). In 1990, Louisiana had
                  about 24,000 commercial saltwater, licensed fishermen (Sharkey, written comm., 1990).
                      Texas ranked third among Central and Western Gulf states in total commercial fishery landings for 1990
                  with nearly 99 million pounds landed, valued at $182 million. In quantity and value, shrimp ranked first, with
                  about 92 million pounds, valued at $17 million. In addition, during 1990, the following three species each
                  accounted for landings valued at over $1 million: yellowfin tuna, blue crab, and American. oyster (USDOC,
                  NMFS, 1991a). In 1989, Texas had about 24,000 commercial saltwater, licensed fishermen (Clagett, written
                  comm., 1990).
                      The Gulf of Mexico yielded the nation's largest regional commercial fishery by weight in 1990. The Gulf
                  fisheries landings were 57 percent of the national total by weight and 20 percent by value. Most commercial
                  species harvested from Federal waters of the Gulf of Mexico are considered to be at or near an overfished
                  condition. Continued fishing at the present levels may result in rapid declines in commercial landings and
                  eventual failure of certain fisheries. Commercial landings of traditional fisheries, such as shrimp, red snapper,
                  and spiny lobster, have declined over the past decade despite substantial increases in fishing effort.
                  Commercial landings of recent fisheries, such as shark, black drum, and tuna, have increasedexponentially over
                  the past five years, and those fisheries are thought to be in danger of collapse (Angelovic, written comm., 1989;
                  USDOC, NMFS, 1991b).
                      Nearly all species significantly contributing to the Gulf of Mexico's commercial catches are estuarine
                  dependent. The degradation of inshore water quality and loss of Gulf wetlands as nursery areas are considered
                  significant threats to commercial fishing (Angelovic, written comm., 1989; Christmas et al., 1988; Gulf States
                  Marine Fisheries Commission, 1988). In addition, conflicts between fishermen using fixed gear (traps) and
                  mobile gear (trawls) continue to be a problem in some parts of the Gulf (Federal Fisheries News Bulletin,
                  1989a and b).
                      Fishery Management Plans (FMP's) are developed by the Gulf of Mexico Fishery Management Council
                  (GMFMC) to assess and manage commercial species of fish that are harvested from Federal waters and in
                  need of conservation. Since 1981, nine FMP's have been implemented for the following species in the Gulf
                  of Mexico: shrimp, stone crab, spiny lobster, coastal pelagics, coral, reef fish, swordfish, red drum, and sharks.
                  The GMFMC has initiated development of additional management plans for butterfish, swordfish, and black
                  drum (Gulf of Mexico Fishery Management Council, 1989; Horst, 1989).
                      The Gulf of Mexico shrimp fishery is the most valuable in the United States accounting for 72 percent of
                  the total domestic production (USDOC, NMFS, 1991a). Three species of shrimp--brown., white, and pink--
                  dominate the landings. The status of the stocks are as follows: (1) brown shrimp yields are at or near the
                  maximum sustainable levels; (2) white shrimp yields are beyond maximum sustainable levels with signs of
                  overfishing occurring; and (3) pink shrimp yields are at or beyond maximum sustainable levels.
                      The shrimp fishery is facing a number of additional problems: an excessive number of vessels given
                  available yields of shrimp; imports of less expensive shrimp from foreign countries accounting for 77.5 percent
                  of domestic consumption; a 10 percent decline in ex-vessel price of domestic shrimp over the past five years;
                  increases in interest rates to finance acquisition of equipment, vessels, and other related fishing needs; increases











                                                                                                                               111-79
              in fuel prices; excessive costs of marine casualty insurance; regulations regarding the use of turtle excluder
              devices; excessive bycatch of finfish; and conflicts with other targeted fisheries (Angelovic, written comm., 1989;
              Gulf States Marine Fisheries Commission, 1988). It has been estimated that for every pound of shrimp landed,
              over nine pounds of valuable finfish are killed and discarded as bycatch (Sport Fishing Institute, 1989a). In
              an attempt to lessen anticipated conflicts between commercial fishing for shrimp, spiny lobster, and stone crab,
              the GMFMC has closed areas in the Eastern Gulf to shrimp trawling during the traditional trap fishing seasons
              for lobster and stone crab.
                   The red drum fishery was closed to all harvest in Federal waters of the Gulf of Mexico on January 1, 1988.
              Stock assessment concluded that red drum were heavily fished prior to moving offshore to spawn and that those
              fish less than 12 years of age were poorly represented in the offshore spawning population. Continued harvest
              of adults from Federal waters would further reduce spawning stock and increase the risk of a collapse of the
              red drum fishery (USDOC, NMFS, 1989a).
                   Red snapper resources in the Gulf of Mexico are believed to be severely overfished from both directed
              and bycatch fisheries. Red snapper is the most important species in the reef fish complex managed under a
              FMP in terms of value and historical landings. The species is presently considered to be in worse condition
              than was red drum when that fishery was closed to all further harvest in Federal waters.
                   The major concern of the stone crab fishery is whether harvest has reached or exceeded maximum
              sustainable yield. Until recently, the fishery has been expanding in terms of increasing catch within traditional
              fishing areas and previously unfished or underfished regions. However, the total harvest has declined steadily
              over the past several years. The GMFMC is considering limitations on the number of fishermen and traps in
              the stone crab fishery.
                   Spiny lobster fishing is practiced exclusively in the Eastern Gulf of Mexico. It is believed that the stock
              is showing signs of growth overfishing. Fishing mortality is high due to the number of undersized lobsters used
              to bait lobster fishing traps and the number of traps in the fishery that far exceed that number required to
              harvest the present yield. Fishermen contend that the present fishery practices are the most optimal for their
              objectives. The GMFMC is considering limitations on the number of fishermen and traps in the spiny lobster
              fishery.
                   The coastal pelagic IMP addresses a number of species. Two of the more important species are king and
              Spanish mackerel. Both species have been extensively overfished and are now under a managed rebuilding
              program. Since the early 1980's there has been a marked absence of a strong year class of king mackerel.
              Spawning stock biomass has exhibited some gains and recruitment is stable at low levels. There is concern over
              the possible need for two management units for king mackerel within the Gulf of Mexico and with the impact
              of the increasing Mexican fishery. Spanish mackerel stocks are showing positive signs of recovery. Spawning
              stock biomass and recruitment appear to be increasing. Most of the Spanish mackerel catch is taken off
              Florida. Capture of 50-80 percent of the yearly commercial allocation within a period of three weeks by
              southeast Florida fishermen has raised questions of conflict with recreational fishermen who believe their
              allocation should be increased.
                   Commercial landings of swordfish have increased steadily over the past several years with serious
              implications for the future. The percentage of older fish and spawning biomass has declined significantly. The
              GMFMC is developing a number of alternatives to better manage this resource.
                   Blue marlin and white marlin are believed to be at or near the point of full exploitation. There is concern
              about the increasing mortality of marlin as bycatch associated with the escalating yellowfin tuna longline fishery
              (Sport Fishing Institute, 1989b). The tuna fishing industry has expanded at an alarming rate in the Gulf of
              Mexico over the past five years. Tuna are now included under the Magnuson Fishery Conservation and
              Management Act of 1976 (MFCMA), and the GMFMC can begin to manage the tuna fishing industry and
              address the marlin bycatch issue. For more information concerning the MFCMA, see Section LBA.g.
                   The taking of stony corals or gorgonian sea fans is prohibited. Fishing for soft coral octocorals is presently
              below the limits of maximum yield. There are significant concerns about the butterfish fishery in that butterfish
              trawlers allegedly destroy coral reef habitat and take a large number of snappers and groupers as bycatch. In
              addition, a newly formed fishery of "live rock" for the ornamental trade is receiving attention due to the
              allegation that "live rock" fishing may purposefully or inadvertently include the harvest of stony coral.











                   111-80
                       The present concern with the condition of the black drum fishery stems directly from the closure, of the
                   red drum fishery. Almost immediately after closure, black drum were accepted as a subs1itute for red drum
                   within the commercial market. The intensive fishing effort for red drum was switched to black drum without
                   need to change fishing gear or technique. As a result, stocks of black drum are believed to be fast approaching
                   a seriously depleted condition. Several Gulf States have instituted interim management measures in State
                   waters to reduce black drum catches while an FMP is developed and implemented (Horst, 1989).
                       A strong market for shark has resulted in soaring catches over the past several years. Shark stocks are
                   unable to sustain the present heavy fishing pressure, and without management, the fishery is expected to
                   collapse within the near future. The GMFMC has requested that Gulf States consider interim management
                   measures while an FMP is developed and implemented (Gulf Fishery News, 1989).

                   4. Recreational Resources and Activities

                       The northern Gulf of Mexico coastal zone is one of the major recreational regions of the United States,
                   particularly for marine fishing and beach activities. Gulf Coast shorelines offer a diversity of natural
                   and developed landscapes and seascapes. Major recreational resources include coastal beaches, barrier islands,
                   estuarine bays and sounds, river deltas, and tidal marshes. Other resources include publicly owned and
                   administered areas, such as national seashores, parks, beaches, and wildlife lands, as -well as designated
                   preservation areas, such as historic and natural sites and landmarks, wilderness areas, wildlife sanctuaries, and
                   scenic rivers. Gulf Coast residents and tourists from throughout the nation, as well as from foreign countries,
                   use these resources extensively and intensively for recreational activity. Commercial and private recreational
                   facilities and establishments, such as resorts, marinas, amusement parks, and ornamental gardens, also serve
                   as primary-interest areas.
                       Predominant among public recreation areas abutting the Gulf of Mexico are Padre Island National
                   Seashore in the WPA and Gulf Islands National Seashore in the CPA- Over 20 years ago Congress set aside
                   these outstanding examples of Gulf coastal beach and barrier island ecosystems to be managed by the National
                   Park Service for the preservation, enjoyment, and understanding of their inherent natural, cultural, and
                   recreational values. Combined, these seashores account for approximately 110 mi of exposed Gulf beachfront,
                   which accommodates over 1.5 million recreational visits a year. Besides beaches these; seashores contain
                   nationally significant forts, shipwrecks, wetlands, lagoons and estuaries, seagrasses, fish and wildlife, and
                   archaeological sites. In 1978, 1,800 ac on Horn and Petit Bois Islands, part of Gulf Islands National Seashore,
                   were designated by Congress as components of the National Wilderness System.
                       Visual No. 2 provides a synoptic view of the location, extent, and components of all the designated
                   recreational areas and major recreational beaches within the marine and coastal areas from Texas to Alabama.
                   Approximately 40 million residents of the Gulf Coast States have a major interest in water-related and water-
                   enhanced recreational activity. Gulf beaches and nearshore marine recreational waters are a major focus of
                   coastal recreation activities. Approximately 13 percent of the nation's population resides in the Gulf Region,
                   which harbors the lowest coastal population density of any region in the continental U.S. (USDOC, NOAA,
                   1990a).
                       The Office of Strategic Assessment of NOAA inventoried public recreation areas in coastal areas
                   throughout the U.S. and determined 308 public agencies owned and/or managed outdoor recreation areas and
                   facilities in Gulf coastal areas. The atlas developed by NOAA provides extensive data on public recreation
                   lands and waters, as well as the number of boat ramps, boating slips, docks, fishing piers, campsites, artificial
                   reefs, and miles of beach for every coastal county or parish associated with the Gulf of Mexico region
                   (USDOC, NOAA 1988c).
                       The Gulf States from Texas to Alabama count about 1.3 million registered motorboats and over 3.5 million
                   paid fishing license holders. The two major recreational areas most directly associated with and potentially
                   affected by offshore leasing are the offshore marine environment and the coastal shorefront of the adjoining
                   states. The major recreational activity occurring on the OCS is offshore marine recreational fishing and diving.
                   Studies, reports, and conference proceedings published by MMS and others have documented a substantial
                   recreational fishery, including scuba diving directly associated with oil and gas production platforms (Witzig,












                                                                                                                                 111-81

              1986; Ditton and Auyong, 1984; Roberts and Thompson, 1983; Ditton and Graefe, 1978; Dugas et al., 1979;
              Reggio, 1989). The NMFS Marine Recreational Fisheries Statistics Survey for the Gulf and Atlantic Coasts
              (USDOC, NMFS, 1990a) and a special report by Schmied and Burgess (1987) indicates there are about 4
              million resident participants in marine recreational fishing and over 2 million tourists who angle for Gulf marine
              species. According to NMFS, over 40 percent of the nation's marine recreational fishing catch comes from the
              Gulf of Mexico, and marine anglers in the Gulf made over 13 million fishing trips in 1989, exclusive of Texas
              (USDOC, NMFS, 1990a). Texas marine anglers using private boats expended over 7 million man-hours to land
              almost 3 million saltwater fish during the 1986-1987 fishing years (Osburn et al., 1988).
                   Table III-10 provides some indication of participation rates and trends in marine recreational fishing in all
              Gulf States except Texas. Marine recreational fishing trips and catch along the Atlantic and Gulf coasts have
              been declining in the last few years (USDOC, NMFS, 1990a). Speckled trout are the most sought sport fish
              in coastal marine waters, whereas snapper and mackerel are some of the more popular offshore sport fish.
              Gulf snapper landings have shown a precipitous downward trend over the last several years, and proposals have
              been made to limit severely the catch by recreational fishermen (Gulf of Mexico Fishery Management Council,
              1990). Marine recreational fishing in the Gulf Region from Texas to Alabama is a major industry important
              to these States' economies. The recreational marine fishing industry accounts for an estimated $769 million
              in sales (equipment, transportation, food, lodging, insurance, and services) and employment for over 15,000
              people, earning more than $158 million annually in the CPA and WPA (Table 111-11) (Sports Fishing Institute,
              1988).
                   The coastal shorelines of the CPA and WPA contain extensive public park and recreation areas, private
              resorts, and commercial lodging. Most of the outdoor recreational activity focused on the Gulf shorefront is
              associated with accessible beach areas. Beaches are a major inducement for coastal tourism, as well as a
              primary resource for resident recreational activity. However, recreational resources, activities, and expenditures
              are not constant along the Gulf of Mexico shorefront, but are focused where public beaches are close to major
              urban centers. Beach use is a major economic factor for many Gulf coastal communities, especially during
              peak-use seasons in the spring and summer.

                                                                    Table III-10


                                                       Marine Recreational Fishing Trips
                                                        in the Gulf of Mexico (1984-1989)

                                                                                 -- thousands of trips --

                                                     1984          1985          1986          1987          1988            1989

                   Louisiana                        1,434         2,446         3,114         2,364         3,338           2,063
                   Mississippi                        546           536          672            920           799             546
                   Alabama                            512           603          675            548         1,104             499
                   Florida (Gulf Coast)            11,451        13,372        13,436        12,217        13,822          10,485
                   Texas                            2,445         7,270           -             -             -               -

                   Guffwidel                       16,388        24,227        17,897        16,049        19,063          13,593
                   'Texas data for 1986-1989 are unavailable and some fishing modes were missing from the 1984-1985
                   Texas data collected by NMFS.

                   Source: Witzig, personal comm., 1990.






















                                                                                       Table III-11


                                                             Economic Activity Associated with Marine Recreational Fishing
                                                                                   in the Gulf of Mexico


                                                                         Employment               Number of                   Wages and                      Capital
                                                   Sales               (person yearsi             EmRIgyees..                  Salaries                   Enenditures

                 Florida                        946,990,600                 15,120                   18,960                   $194,857,800                  W,699,600

                 Alabama                         42,703,800                   682                      855                      8,787,000                    2,105,900

                 Mississippi                     37,958,900                   606                      760                      7,810,600                    1,871,900

                 Louisiana                      173,223,100                  2,766                   3,468                     35,643,300                    8,542,300

                 Texas                          514,853,500                  8,221                 -10,308                     105,939,000                  25,389,300


                 Gulfwide                    $1,715,729,900                27,395                    34,351                   $353,037,700                  $84,609,000




                 Source: Sports Fishing Institute, 1988











                                                                                                                                 111-83
                5. Archaeological Resources

                    Archaeological resources are any prehistoric or historic site, building, structure, object, or feature that is
                manmade or modified by human activity. Significant archaeological resources are defined in 36 CFR 800,
                Section 60.6. The MMS has previously contacted the State Historic Preservation Officers for all Gulf Coast
                States and requested them to provide a list of those National Register of Historic Places that are in their State's
                coastal zones and that could potentially be affected by OCS leasing activities. These properties are depicted
                on Visual No. 2.


                a. Historic

                    With the exception of the Ship Shoal Lighthouse, historic archaeological resources on the OCS consist of
                shipwrecks. A 1977 MMS archaeological resource baseline study for the northern Gulf of Mexico indicated
                that 2 percent of the pre-20th century shipwrecks and 10 percent of all wrecks reported lost between 1500 and
                1945 have known and/or verified locations (CEI, 1977). Management of this resource was accomplished by
                establishing a high-probability zone (ARZ1) for the occurrence of historic shipwrecks. The use of geographic
                and cultural factors as indicators of high shipwreck potential delineated this zone. A recently completed study
                by Texas A&M University (Garrison et al., 1989) updated the shipwreck database. Statistical analysis of over
                4,000 potential shipwrecks in the northern Gulf indicated that many of the OCS shipwrecks occur in clustered
                patterns related mainly to navigation hazards and port entrances. The study recommended significant changes
                to the ARZ1 as well as changes in the MMS historic shipwreck survey methodology, including tightening
                magnetometer survey finespacing intervals from 150 to 50 m.
                    On November 30,1990, the MMS Gulf of Mexico OCS Region issued an LTL that redefined those blocks
                in the Gulf Region that are considered to have a high probability for the occurrence of historic period
                shipwrecks. The LTL reduced the total number of blocks on the Gulf of Mexico OCS with a high probability
                for historic shipwrecks from 3,410 to 2,263. The redefinition of the historic shipwreck high probability zone
                was based on the recommendations of the Texas A&M University study as well as in-house analyses of the
                study's conclusions and technical aspects of magnetometer survey. The redefined high-probability zone consists
                of three subzones--a zone defined as occurring from the shoreline to 10 kin from shore; 21 0.5-degree square
                high-probabilityquadrats associated with cultural and geographic features (such as historic ports, barrier islands,
                reefs, etc.); and specific high-probability search polygons associated with shipwrecks located outside of the two
                aforementioned zones.
                    The Texas A&M University study also examined variables affecting the site formation process and
                shipwreck preservation potential. The study concluded that the eastern part of the CPA would have a high
                shipwreck preservation potential because of the thick Holocene deltaic sediments found there. This high
                degree of wreck preservation would not be expected in the most western part of the CPA, where sedimentation
                rates are slower. In the WPA, preservation potential is expected to be moderate to high throughout the area.
                Except for localized coastal areas with active sand deposition, shipwrecks in the EPA are not expected to have
                a high potential for preservation.
                    Remote-sensing surveys required by MMS have recorded evidence of approximately 57 potential
                shipwrecks, 80 percent of which are in ARZ1, which, according to the baseline study, is where the highest
                incidence of shipwrecks should occur.

                b. Prehistoric

                    The advent of man into the Gulf of Mexico region is currently accepted to be around 12,000 B.P. (Aten,
                1983). According to the sea-level curve proposed for the northern Gulf by Coastal Environments, Inc. (CEI,
                1982), sea level at 12,000 B.P. would have been approximately 45 m below the present sea level. On this basis,
                the continental shelf shoreward of the 45-m bathymetric contour would have potential for prehistoric sites
                dating subsequent to 12,000 B.P. The 1977 baseline study (CEI, 1977) proposed that terrestrial sites of a given
                period will be analogous to area sites occurring on the now-submerged shelf. Remote-sensing surveys have
                been very successful in identifying the geographic features that have a high probability for associated prehistoric
                sites.











                  111-84
                       Regional geological mapping studies by MMS allow interpretations of specific geomorphic features and
                  assessments of archaeological potential in terms of age, the type of system the geomorphic features belong to,
                  and geolo                that formed and modified them. The potential for site preservation must also be
                           , gic processes
                  considered as an integral part of the predictive model. In general, sites protected by sediment overburden have
                  a high probability for preservation from the destructive effects of marine transgression. The same holds true
                  for sites, submerged in areas subjected to low wave energy and for sites on relatively steep shelves during
                  periods of rapid rise in sea level.
                       Tholugh lease-block surveys have identified many specific areas in the Gulf as having a high potential for
                  prehistoiic sites, oil and gas development has generally avoided rather than investigated these high-probability
                  areas for archaeological content.

                  Central Gulf of Merico

                       Geomorphic features that have a high probability for associated prehistoric sites in the Central Gulf include
                  barrier islands and back-barrier embayments, river channels and associated floodplains and terraces, and salt-
                  dome features. Holocene deltaic deposits of the Mississippi River characterize the easteni part of the CPA-
                  Deltaic geomorphic features, some with a high probability for preservation of prehistoric sites, are abundant
                  in the area. The thickness of archaeologically sterile open-shelf Holocene marine sediments in some areas
                  (generally closer to the active Mississippi Delta) may preclude recovery of site information in the underlying
                  strata.
                       Holocene sediments form a thin veneer or are absent over the majority of the western part of the CPA
                  (USDOI, MMS, 1984a). Many large, late Pleistocene fluvial systems (e.g., the Sabine-CalaLsieu River Valley)
                  are within a few feet of the seafloor in this area. A study funded by MMS to locate prehistoric archaeological
                  sites in association with the buried Sabine-Calcasieu River Valley was completed in 1986 (CEI, 1986). Five
                  types of relict landforms, were identified and evaluated for archaeological potential. Coring of selected features
                  was performed, and sedimentary analysis suggests the presence of at least two archaeological sites.
                       Lease-block surveys from other areas of the western part of the CPA have produced evidence of
                  floodplains, terracing, and point-bar deposits in association with relict late Pleistocene fluvial systems.
                  Prehistoric sites associated with these features would have a high probability for preservation. Salt diapirs with
                  bathymetric expression have also been recorded during lease-block surveys in this area. Solution features at
                  the crest of these domes would have a high probability for preservation of associated prehistoric sites. The Salt
                  Mine Valley site on Avery Island is a Paleo Indian site associated with a salt-dome solution feature (CEI, 1977).
                  The proximity of most of these relict landforms to the seafloor facilitates further investigation and data
                  recovery.

                  Western Gulf of Meirico

                       The Western Gulf includes the same geomorphic features associated with prehistoric sites as occur in the
                  Central Gulf. The western portion of the WPA contains Holocene deltaic deposits of the Colorado and Brazos
                  Rivers. Holocene sediments west of 96OW longitude range from 4 to 44 in thick; sediments east of 960W.
                  longitude begin thinning. Lease-block surveys have recorded geomorphic features with a high probability for
                  the occurrence and preservation of prehistoric archaeological sites. The thickness of archaeologically sterile
                  open-shelf Holocene marine sediments in some area may preclude recovery of site information in the
                  underlying strata.
                       The geologic conditions that affect prehistoric site occurrence and preservation in the: most eastern part
                  of the WPA are similar to those described above for the western part of the CPA- The McFaddin Beach site,
                  in this part of the WPA, has produced late Pleistocene megafaunal remains and lithics from all archaeological
                  periods.












                                                                                                                                  111-85
               6. Coastal Zone Management Plans

               State Coastal Zone Management Programs

                    At the State level, a lead State agency oversees implementation of the CZM program and administers the
               Federal grant funds. Local governments are involved in the implementation of State CZM programs, either
               formally or informally. Federal agencies are involved in the development and implementation of State CZM
               programs. Once the programs are federally approved, Federal agencies must ensure that their actions are
               consistent to the maximum extent practicable with the enforceable polices of approved State programs. State
               and Federal agencies work together on joint planning and permitting, which reduces the regulatory burden on
               the public (USDOC, NOAA, 1989).
                    The role of the Federal agency includes State assistance, approval determination, review and approval of
               financial assistance, continued monitoring and formal evaluations, review and approval of program changes,
               mediation, and consistency appeals. Projects conducted under Section 306 of the CZMA, which funds State
               coastal management program implementation, include hazards protection, natural resource protection and
               development, public access, urban waterfront redevelopment, ports and marinas, and improved government
               operations. Section 306 program implementation funds are based on a formula set by State coastal population
               and shoreline mileage. In fiscal year 1990, 29 states and territories were scheduled to receive Section 306
               grants totaling $35.3 million (USDOC, NOAA, 1990). States are required to match the Federal funds dollar
               for dollar for Section 306 grants. The State must submit Routine Program Implementations to the OCRM on
               a case-by-case basis, periodically or annually. On the average, at least three out of four of these are accepted.
               In the near future, NOAA is planning to conduct an investigative summary of all the RPI's and amendments
               that have been submitted to OCRM for approval. The NOAA evaluates the program changes, lack of Federal
               agency involvement in the State review process, early consultation with the OCRM, and the content of
               submissions. Amendments must by submitted by the Governor of a State or by the head of an agency. At
               least one public hearing must be held with a 30-day notice. Section 307 of the CZMA contains the Federal
               consistency provisions, which impose certain requirements on Federal agencies to comply with approved State
               CZM programs. Section 309, amended in 1990, does not require states to match Federal funding. A
               continuing review of the performance of States with approved CZM programs is required under Section 312
               of the CZMA, as amended.

                    State of Alabama Coastal Area Management Program

                    The Alabama Coastal Area Board (CAB), acting pursuant to the Alabama Coastal Area Act (ACAA) of
               1976, was formerly the principal agency responsible for the management of the Alabama coastal area. As a
               result of passage of the Alabama Act 82-612, the CAB was abolished. Its functions were divided between the
               Alabama Department of Community Affairs (ADECA) and the Alabama Department of Environmental
               Management (ADEM). The ADECA has overall responsibility for plan development, improvements, policy
               development and refinements, planning, research, and general oversight and all other nonpermit-related
               activities under the Alabama Coastal Area Management Program (ACAMP). All permit, enforcement,
               regulatory, and monitoring activities, and the adoption of rules and regulations to carry out ADECA policies
               are the responsibility of the ADEM. In July 1990, the Governor signed an executive order calling for an
               "Alabama Coastal Waters Initiative" to examine the various coastal programs and to develop a long-term
               coastal management plan. Outcomes may include revisions to the ACAMP.
                    The ADEM rules and regulations are divided into three categories: (a) general rules and regulations; (b)
               resource use rules and regulations for energy facilities, waste disposal, dredging, and public access; and (c)
               natural resource rules and regulations for water and air quality and nearshore and coastal environments.
                    The Alabama coastal counties are Baldwin and Mobile. Within the coastal zone, two areas--the Port of
               Mobile and the Mobile-Tensaw River Delta--have been designated as geographic areas of particular concern.
               The general rules and regulations are supplemented by special priority of use guidelines for geographic areas
               of particular concern.











                  111-86
                      The ACAA provides statutory authority to review all coastal resource uses and activities that have a direct
                  and significant effect on the coastal area. Specifically, the ADEM must find specific uses or activities that
                  require a' State permit to be consistent with the coastal policies noted above and the more detailed rules and
                  regu          omulgated as part of the ACAMP. Under the ACAA, State agency activities must be consistent
                  with= policies and ADEM findings. Further, ADEM must make a direct permit-type review for uses
                  that are not otherwise regulated at the State level (Code of Alabama, section 9-7-20). The ADEM also has
                  authority' to review local government actions and to assure that local governments do not un-Teasonably restrict
                  or exclude uses of regional benefit Ports and major energy facilities are designated as uses of regional benefit.

                      State of Mississippi Coastal Program

                      The Mississippi Coastal Program (MCP) is administered by the Mississippi Commission on Wildlife
                  Conservation through the Bureau of Marine Resources (BMR). The primary coastal management statute is
                  the Coastal Wetlands Protection Law (Mississippi Code, section 49-27-1). The authorities of certain other
                  agencies are incorporated into the MCP pursuant to the Mississippi Code (section 57-16-6), -which requires the
                  coastal program to incorporate "all applicable constitutional provisions, laws and regulations of the State of
                  Mississippi." The BMR, the Bureau of Pollution Control, the Bureau of Land and Water Resources, and the
                  Department of Archives and History are identified collectively as the "coastal program agencies." The
                  Mississippi Commission on Wildlife Conservation, acting through the BMR, consolidates authorities previously
                  assigned to the Marine Resources Council and the Marine Conservation Commission, including authority to
                  study and develop plans, proposals, reports and recommendations for the development and utilization of the
                  coastal and offshore lands, waters, and marine resources of the State (Mississippi Code, sections 57-15-1
                  through 17). Other major features of the MCP include statutes related to fisheries (Mississippi Code, section
                  49-15-1 through 69), air and water pollution control (Mississippi Code, sections 49-17-1 through 43), surface
                  and groundwater (chapters 3 and 4, Title 51 of Mississippi Code,) cultural resources (Mississippi Code, section
                  39-7-11), and the disposal of solid waste in marine waters (Mississippi Marine Litter Act of 1989, Senate
                  Legislative Bill No. 2675.) The Marine Debris Act prohibits the disposal of any debris intocoastal waters and
                  establishes strict penalties up to $10,000 for violators. For the purposes of the coastal program, the boundary
                  encompasses the three coastal counties of Hancock, Harrison, and Jackson and all coastal waters.

                      State of Louisiana Coastal Zone Management Program

                      The basis for the Louisiana Coastal Zone Management Program (LCZMP) is the State and Local Coastat
                  Resources Management Act of 1978 (La. R.S. 49:213.1; Act 361). Former sections of Part 11 of Chapter 2,
                  designated as R.S. 49:213.1 to 49:213.22, were redesignated as Subpart C. The LCZMP consists of R.S.
                  49-214.21 to 49:214.40, pursuant to Section 7 of Act 1989, 2nd Ex. Session, No.6, and on authority of R.S.
                  24:253. The Act puts into effect a set of State coastal policies and coastal use guidelines that apply to coastal
                  land and water use decisionmaking. A number of existing State regulations are also incA)rporated into the
                  program--those concerning oil and gas and other mineral operations; leasing of State lands for mineral
                  operations and other purposes; hazardous waste and radioactive materials; management ofwildlife, fish, other
                  aquatic life, and oyster beds; endangered species; Superport; and air and water quality.
                      The Act also authorized establishment of Special Management Areas. Included or planned to be included
                  as Special Management Areas are the Louisiana Superport (LOOP), Marsh Island, artificial barrier islands to
                  protect deteriorating coastal areas, and freshwater and sediment diversion projects to offset land loss and
                  saltwater encroachment. For purposes of the CZMA, only that portion of LOOP within Louisiana's coastal
                  zone is part of the Special Management Area. In April 1989, the Louisiana Legislature passed Act 6, creating
                  the Wetlands Conservation and Restoration Authority and establishing a Wetlands Conservation and
                  Restoration Trust Fund to underwrite restoration projects. The Legislature also reorganized part of the
                  Louisiana Department of Natural Resources (DNR) by creating the Office of Coastal Restoration and
                  Management.
                      The DNR is the designated State agency for receiving and administering Section 306 awards. The
                  Secretary delegated this authority to the Coastal Management Division. Several other agencies, including the











                                                                                                                                 111-87

                Department of Wildlife and Fisheries and the Department of Health and Human Resources, play a role in the
                LCZMP implementation. The Department of Environmental Quality carries out the State air and water quality
                programs.
                    The coastal use guidelines are based on seven general policies outlined in Act 361. They are implemented
                through coastal use permits and in-lieu permits. In-fieu permits provide for the use of permit requirements
                existing before the Act took effect to fulfill the role of coastal use permits, thereby avoiding duplicated
                permitting procedures.
                    Act 361 identified a number of State concerns subject to coastal use permitting requirements. State
                concerns, which are listed in Act 361, that could be relevant to a lease sale and its possible direct effects or
                associated facilities and nonassociated facilities are (a) any dredge and fill activity that intersects more than one
                water body, (b) projects involving the use of State-owned lands or water bottoms, (c) national interest projects,
                (d) pipelines, and (e) energy facility siting and development. Local governments (parishes) may assume
                management of uses of local concern by developing a local coastal program consistent with Act 361.

                    State of Teras Coastal Management Program

                    Of the States affected by the proposed sales, only Texas does not have a federally approved CZM plan.
                In May 1981, the State of Texas formally withdrew from the Federal CZM program. In 1989 the Texas
                legislature foresaw the need to reexamine the State's coastal resources and called for the creation of a Coastal
                Management Plan. Under the leadership of the Texas General Land Office, with the participation of State
                and Federal agencies, local officials, environmental representatives, the business community, and coastal
                citizens, a draft plan was developed and published in 1990. The plan identified eight issues, discussed solution
                strategies, and provided recommendations for action. Through a process of public input and consensus
                development, coastal erosion/dune protection, wetland loss, and beach access emerged as issues of primary
                importance. Other issues identified in the Texas Coastal Management Plan included marine debris, oil spills,
                hazardous waste, freshwater inflow into bays and estuaries, and nonpoint-source pollution. A final plan was
                published by the Texas General Land Office in January 1991.
                    Subsequent to publication of the above plan, the State decided to seek Federal approval of its CZM plan,
                which will focus on coastal public lands. The State estimates that it may take a year to a year and a half before
                a final set of guidelines and procedures are developed.















   SECTION IV

   ENVIRONMENTAL
   CONSEQUENCES               IV












                                                                                                                             IV-3
               IV. ENVIRONMENTAL CONSEQUENCES

               A. PROPOSED ACTION SCENARIO

                   The Gulf of Meidco OCS Region has formulated development scenarios to provide a framework for
               detailed analyses of potential impacts of proposed OCS oil and gas lease sales in the CPA and WPA (proposed
               Sales 142 and 143, respectively). Each of the scenarios is a hypothetical framework of assumptions and
               estimates on the amounts, timing, and general locations for OCS exploration, development, and production
               activities and facilities, both offshore and onshore. Because each of them necessarily presents only approximate
               conditions that might be associated with a sale, the scenarios cannot be used to predict future off and gas
               activities. These activities are unpredictable prior to a sale; they do not become clear until offshore and
               onshore development proceeds from lease through production. For example, factors such as the contemporary
               economic marketplace and available support facilities and pipeline capacities at the time of future infrastructure
               development are all unknowns. Notwithstanding these unpredictable factors, the scenarios represent best
               assumptions and estimates on a set of future conditions that are considered reasonably foreseeable and suitable
               for presale impact analyses. It should also be noted that these development scenarios do not represent an
               MMS recommendation, preference, or endorsement of any level of leasing or offshore operations or of the
               types, numbers, and/or locations of any onshore operations or facilities.
               1. Resource Estimates, T'imetables, and Subarea Descriptions

                   The Base Case and High Case described in this section are used to assess the sale-specific impacts of the
                   proposed actions. These scenarios are based on recent trends in the following factors:

                        -   the amount and location of leasing, exploration, and development activity;

                        -   existing offshore and onshore oil and/or gas infrastructure;

                        -   industry-practice information;

                        -   oil and gas technologies, and the economic considerations and environmental constraints
                            of these technologies; and

                        -   the estimates of undiscovered, unleased oil and gas resources in the planning areas.

                   The resource estimates used for the Base Case and High Case are based on two factors: (a) the
               conditional estimates of undiscovered, unleased oil and gas resources in the planning area; and (b) estimates
               of the portion or percentage of these resources assumed to be leased, discovered, developed, and produced
               as a result of the proposed actions. The resource estimates for the Base Case and High Case differ as follows:
               the Base Case estimates are based on the mean or "expected" case values of total undiscovered, unleased
               resources; the High Case estimates, which are based on the high or 5 percent values, correspond to a 5 percent
               chance of that amount or more occurring.
                   The Base Case--because it is based on the mean or "expected" resource estimates--is used for the principal
               impact analyses of the proposed actions, including the Cumulative analyses. The High Case is used to provide
               a supplementary analysis of the effects that could occur if a greater, though much less likely, amount of
               resources was discovered and developed. Tables IV-1 through IV-6 provide a summary of major elements of
               the Base Case and High Case and some of the related impact-producing factors for each proposed action.
                   Central Gulf Sale 142: The estimated amounts of oil and gas resources expected to be developed--as well
               as the total number of exploration and delineation wells, production platforms, and development wells, and the
               total miles of offshore pipeline needed to develop and produce the estimated resources--are included in Tables











                  IV-4

                  IV-1 an  Id IV-2 for the Base Case and High Case. These tables also include estimates of the major
                  impact-P, roducing factors or agents related to the estimated levels of exploration, development, and production
                  activity. @ Table IV-2 shows the disaggregation of these factors to the various offshore subareas in the CPA, and
                  Figure IV,-1 depicts the location of the four offshore subareas in the Central Gulf.
                       For purposes of analysis, the life of the proposed action is assumed to be 35 years. Proposed Sale 142 will
                          ' ' March 1993. Under the Base Case, exploratory activity takes place over an 11-year period
                  occur In
                  (1994-2004). The most intense level of exploratory activity occurs from 1998-1999, development activity begins
                  in 1995 with the installation of the first production platform and ends in 2017 with the drilling of the last
                  development wells, and production of oil and gas takes place from 1995-2026. Under the High Case,
                  exploratory activity takes place over an 11-year period (1994-2004). The most intense level of exploratory
                  activity occurs from 1997 to 1999, development activity begins in 1995 and ends in 2018, and production of oil
                  and gas extends through 2026. By the end of 2027, all platforms associated with the proposed action will be
                  removed.
                       Western Gulf Sale 143: The estimated amounts of oil and gas resources expected to be developed--as well
                  as the total number of exploration and delineation wells, production platforms, and development wells, and the
                  total miles of offshore pipeline needed to develop and produce the estimated resources--are included in Tables
                  IV-1 and IV-3 for the Base Case and High Case.                 These tables also include estimates of major
                  impact-producing factors or agents related to the estimated levels of exploration, development, and production
                  activity. Table IV-3 shows the disaggregation of these factors to the various offshore subareas in the WPA,
                  and Figure IV-1 depicts the location of the three offshore subareas in the Western Gulf.
                       For purposes of analysis, the life of the proposed action is assumed to be 35 years. Proposed Sale 143 will
                  occur in August 1993. Under the Base Case, exploratory activity takes place over an 11-year period
                  (1994-2004). The most intense level of exploratory activity occurs from 1997-1998, development activity begins
                  in 1995 with the installation of the first production platform and ends in 2016 with the drilling of the last
                  development wells, and production of oil and gas takes place from 1995-2026. Under the High Case,
                  exploratory activity takes place over an 11-year period (1994-2004), development activity begins in 1995 and
                  ends in 2019, and productionof oil and gas extends through 2026. By the end of 2027, all platforms associated
                  with the proposed action will be removed.
                       In order to properly analyze impact-producing factors over the life of a proposed action for the Base Case
                  and High Case and the OCS Program analysis, each planning area was subdivided into offshore subareas.
                  Estimates of resources, facilities required, and peak annual facilities were redistributed into each offshore area.
                  The following is a brief description of the geologic characteristics and resource potential of each offshore
                  subarea.


                  Central Gulf of Merico Offshore Subareas C-1, C-2, C-3, and C-4

                       C-1: This subarea encompasses mostly the Miocene and Pliocene Trend of the Louisiana Shelf and
                  consists of a thick sequence of sand and shale producing both off and gas.
                       C-2: This subarea encompasses the Pleistocene Trend located on the shelf and upper slope offshore
                  Louisiana. The area is also characterized by thick sequences of sand and shale similar to the sediments of
                  Subarea C-1, producing both oil and gas. Continued interest along the eastern extension of the Flexure Trend
                  can be expected.
                       C-3: This subarea represents an area comprised of several trends predominantly affected by the delta at
                  the mouth of the Mississippi River. The area around the mouth of the river is comprised of sands and shales
                  of a deltaic environment with ages of production ranging from Miocene to Pleistocene. Both oil and gas
                  production is expected. In the northern portion of C-3, the area becomes gas prone. Here shallow
                  accumulations of gas are located within the "Miocene Bright Spot Trend."
                       C-4: This subarea is a portion of the Cenozoic Deepwater Trend located to the south of'Subareas C-2 and
                  C-3. With the possibility of sediment being deposited in deep water and the existence of large structures, oil
                  and gas can be expected. A large portion of this area is considered to have a low probability of producing
                  economic quantities of hydrocarbons.






























                                                                                                  Table IV-1

                                                Expected oil and Gas Production in the Gulf of Mexico over the Life of the Proposed Action (1992-2027)

                                                                                                                     Projected (total/peak annual)
                                                                                                   ---------------------------------------------------------------
                                                                          Total
                                                                           to        1990                 Sale                                                Sale
                                                                          Date     Annual             (Base Case)             All OCS Sales                (High Case)
                         Central Gulf of Mexico     (Sale 142)           -------   ------          ---------------           ----------------            --------------
                         -----------------------------------
                         Reserve/Resource Projection
                             Oil (Bbbl)                                   7.858    0.245            0.140    0.007            5.460     0.239            0.310   0.015
                             Gas (tcf)                                    80.276   3.447            1.400    0.069            50.290    3.267            2.930   0.144


                         Western Gulf of Mexico     (Sale 143)
                         -----------------------------------
                         Reserve/Resource Production
                             Oil (Bbbl)                                   0.253    0.025            0 050    0.002            1.210     0.041            0.130   0.006
                             Gas (tcf)                                    13.508   1.422            0:740 / 0.036             22.500    1.077            1.820   0.089


                         Eastern Gulf of Mexico
                         -----------------------------------
                         Reserve/Resource Production
                             Oil (Bbbl)                                        0        0             NA / NA                 0.190     0.008                NA   NA
                             Gas (tcf)                                         0        0             NA / NA                 1.050     0.042                NA   NA






















                                                                                                                                  Table IV-2

                                                                                                 Offshore Scenario Infornation Related to Sale 242 for Years 1993 to 2027

                                                                                                                                  offshore sub&rea*

                                                                                     C-1                               C-2                               C-3                               C-4                        Total Central  Odif
                                                                            as" Case          Bigh CA"       Base  Case           Righ Case       Be"   Case,     Sigh Cass         Base, Case        Sigh Case    Be"      Cass     Bigh Case
                         Offshore (Total     Peak Year-)


                         well* Drilled
                             Explorati, and Delineation Wells               25      4         40      7         60    11          95    16        120   21        105     32        133   24          220   37     340      60       340      90
                             Develop-t Wells...                             20      2         40      2         4S    4           90    5         83    7         ISO     10        200   a           220   12     250      20       520      30
                             oil Wall*                                      20      2         20      1         25    2           45    3         45    3         95      3         50    4           110   6      130      10       270      15
                             Gas Wells                                      10      2         20      2         20    2           43    3         40    3         es      5         SO 1  4           100   6      120      10       250      15
                         Platfoxis Cowlex Installations
                             U-b.r installed                                  6     1           6     1         5     1           9     1         10    2         18      2         9     1           17    2         30    3         so      S
                         Space Use 1,oss (ha)                               1800    90        2800    90        0     0           0     0         600   30        900     43        0     0           0     0      2400     120      2700     13S
                         structure Rasiovals Doing Explosives               12      Rk        12      zA.       2  / VA           3  / KA,        S     /Ilk        7     /ELL      I     Rk          2  / m&         20    5         24      0
                         Method of Oil Transportation
                             P-t piped                                  .-Nk        RL        Rk      Kh        UK /RL            RL /Rk          Rk    /Rk       Rk      /IRA.     RL RL             Rk /HL          9es/  989       9es/    98%
                             Percent Barged                                 Sk      wk        RL      Nk        VA vu.            Hk Rh           Nk    Kk        Sk      Nk        VIA ILL           m  Nk           IS/   is          it/   it
                             percent Tankered                               Nk      Kh        Rk      VA        RL Rk             Sk RL           Rk    Rk        Rh      NA        Rk Rk             wk sk           <t/   <It       <it/    <it
                         Shuttle Tanker Traffic (trip.)                       0     0           0     0         0     0           0     0         2     1           5     1         0     0           0     0         2     1           S     /I
                         Barge Traffic (trip.)                              35      2         01      4         3     1           6     1         39    2         91      4         0     0           0     0         77    4        178      8
                         pipeline Length (k.)                               48      e         40      8         40    0           72    8         80    7         144     26        72    e           136   26     240      24       400      40
                         pipeline Displaced Gdizeuts (1,000 W)              240     40        240     40        0     0           0     0         SO    40        120     40        0     0           0     0      320      80       360      so
                         Bottm Area Disturb&=*$ (ha)
                             front rig osiplao,enents                       38      6         60      21        23    4           36    6         45    e         69      12        34    6           55    9      144      2S       229      30
                             fros structure explaoseent.                    30      Ilk       30      RL        4  VIA            e  VIA          22    Rk        IS      wk        3  RL             3  UK           48    UK        60      wk
                             f.ce pipeline project.                         is      3         2S      3         13    3           23    3         26    2         46      3         23    3           44    5         77    8        120      13
                         Accident.
                             offshore oil spills
                             >1 and < 50 bbl                            '-*-nk      VA        VA      Rk        NJL Rk            UK Rk           NA    RA        RK      R&        NA NK             Rk Nk           21    Nk        47      Rk
                             >50 and <1,000 bbl                             UK      NA        a&      Rk        sh SA             Nk VA           NA    KA        RK      Rk        RL Wk-            Nk RL           I     Nk          2     Nk
                             > 1,000 bbi                                    Kk      Hk        sk      Rk        RX SA             sk Rk           sk    NA        RA,     UK        Rk Nk             RL Nk           1     RL          I     UK
                                                                              0     0           1     1         1     1           1     1         1     1           3     1         2     1           3     1         4     1           e     I
                             i.-..It:.d other pollutant Spill.                      1           2     1                                                                                                               20    1         23
                             Bl
                             D                                                                                  2     1           4     1         3     1           8     1         4     1           9     1                                 1
                         S.Ppo    Activities
                             Selloopter Trip. (1,000 trip.)                 69      VA        71      Nk        62 VIA            ill UK          123   Nk        222     NA.       114 Rk            215 RL       368      Rk       619      Nk
                             Service V ... 1 Trip.                       2,100      NA      2,600     RL    3,100  VA         5,400  RL      6,000      NA    10,800      aA.       6,400 HA     11,800  RL      27,600     Nk     30,800     m
                         offshore operational wastes
                             Drilling rluida (1,000 bbl)                    313     42        555     63     732   105        1,205  l4e     1,430      297     2,535     289       1,638 225     2,9e7  345      4,113     563    7,362      e4S
                             Drill Cutting. (1,000 bbl)                     7S      10        131     16     176      26          305   37        344   49        600     72        393   56          708   86     See      140    1,744      210
                             Sanitary and D-ti. Waste    (1,000 .0)         80      Nk        98      Rk     135   Rk             236 Hk          278   Rk        502     Rk        294 Nk            544S Hk      787      RL     1,3e2      VA.
                             Produced water* (1,000 bbl)                24,675      NA     49,349     RK   60,272  NA      111,036   Rk    109,4522     Ilk  231,580      Hk  223,374  Rk      268,593   Nk    317,942      UK   660,559      Uk
                             produced Send& (1,000 bbl)                       6     Rk        14      NJL       11 RA             25 RL           23    Ilk       S2      RA        29 RL             63 RL           69    RL       IS4      Uk
                         offshore Air Emissions (1,000   -tri. tons)
                             Nitrogen Oxides                             12.98      sk      13.16     Rk    10.82  wh         19.74  Rk      21.63      Rk      39.48     Rk        19.47 Rk     37.2e   KA      64.90      Rk     109.66     NA
                             Carbon Monoxide                                1.88    Rk        1.91    NA     1.56  Ilk            2.86 Rk         3.13  Hk        5.72    Rk        2.01 Rk           5.40 RA      9.38     sk     15.80      N&
                             gulf- oxides                                   0.17    Rk        0.10    wk     0.14  Rk             0.27 Rk         0.28  Rk        0.54    Nk        0.25 Rk           0.51 Rk      O.SS     KA,      2.49     Rk
                             Total Bydrocarbon Corpounds                    4.07    sk        4.00    Nk     3.34  Hk             6.12 UK         6.79  Kk     22.25      Rk        6.11 RX      11.57   Wk       20.37     UK     34.02      Rk
                             Total Suspended Particulate.                   0.26    Rk        0.27    VIA    0.22  NA             0.42 Sk         0.44  NK        O.e2    Kk        0.39 Rk           0.78 VA      1.31     Rk       2.29     Rk


                               Sea rigurs IV-2.
                               Peak year fig=.. for individual aubareas my not add to the peak year figure for the total planning area because the peak years for subareas my not occur sixultaneco-ly.
                         ...   not all davelopmat wile classified as oil or gas produce.
                         ....  The n-b.. of spills in W.- cannot be revealed because proprietary inforeation related to projected oil reserve. would be exposed.














                                                        96                                                     90                                                   84

                        31-                                                                                                                                                                                    -.31
                                                                                                                                      AL
                                                                                                              MS
                                               TX                                    LA                                                    E-
                                                                                                                    C-4                                               E-2
                                                                                                                                                                                        FL
                                                                             C-1                                 -3                           E-1                                    000
                                           %                                                        C-2                                                    -4
                                                                                            C                                                               1                                                  -28
                        28-
                                                                                                                       C-3                   E-3                                     E-3
                                                                                                                                                                      E-2
                                                   W-11   r
                                                                   W-2                           C-2



                                                                                                                                             E-4
                                                                                                           C-4
                                 W-1                                  W-3                            CENTRAL
                                                                                                                                                                                                       E-4
                                         WESTERN[ PLANNING AREA                                  PLANNING AREA
                                                                                                                                                   EAJTERN PLANNING AREA

                                                                                                                                                                           E-5
                        25-                                                                                                                                                                                    -25






                                                        96                                                      90                                                   84



                            WESTERN COASTAL AREA                               CENTRAL COASTAL AREA                         CENTRAL COASTAL AREA                          EASTERN COASTAL AREA
                                        W-1                                                C-1                                           C-3                                            E-1
                      Aransas, Calhoun, Cameron, Jackson,               Cameron, Calcasieu, Iberia, Lafayette,           Jefferson, Orleans, Plaquernines,      Escambia, Santa Rosa, Okaloosa, Walton, Bay
                      Kenedy, Weberg, Nueces, San Patriclo,                             Vermilion                            St. Bernard, St. Tammany                                   E-2
                              Refugio, Victoria, Willacy                                   C-2                                           C-4                       Gulf, Franklin, Wakulla, Jefferson, Taylor,
                                        W-2                            Ascension, East Baton Rouge, Lafourche,             Baldwin, Hancock, Harrison,                             Dixie, Levy
                          Brazoria, Chambers, Fort Bend,              Livingston, St. Charles, St. James, St. Mary,           Jackson, Mobile, Stone                                    E-3
                        Galveston, Hardin, Harris, Jefferson,       St. John the Baptist, Tang!pahoa, Terrebonne,                                              Citrus, Hernando, Pasco, Pinellas, Hillsborough,
                         Liberty, Matagorda, Montgomery,                           West Baton Rouge                                                               Manatee, Sarasota, Charlotte, Lee, Collier
                              Orange, Waller, Wharton                                                                                                                                   E-4
                                                                                                                                                                                 Monroe, Dade




                        Figure IV-1. Gulf of Mexico OCS Planning Areas and Coastal and Offshore Subareas.




















                                                                                                                                   Table IV-3

                                                                                               offshore Scenario information Related to Sale 143 for Years 1993 to 2027

                                                                                                                               Offshore Subarea-
                                                                                   ----------------------------            ----------------------------            ---------------------------              ---------------------------
                                                                                                 W-1                                    W-2                                    W-3                                Total Western
                                                                                   Base Case               High Case       Base Case             High case         Base Case            High case           Base Case            High Case
                                                                                   ---------------------------             ---------------------------             ---------------------------              ---------------------------
                          Offshore (Total        Peak Year-)
                          ----------------------------

                          Wells Drilled
                             Exploration and Delineation Wells                          5      1           10       2          25     4             so     10      100        30        360        69       210      35          420      00
                             Development Wells...                                       5      1           10       1          15     1             30     2           90     4         230        17       110      s           270      20
                              oil wells                                                 0      0             0      0          5      1             10     1           45     2         110        8        50       2           120      9
                              Gas Wells                                                 5      1           10       1          10     1             20     1           45     2         120        9        60       3           ISO      12
                          Platform Complex Installations
                             Number Installed                                           1      1             1      1          2      1             5      1           7      1             24     5        10       2           30       6
                          Space Use Loss (ha)                                         300      15          300 /    15         0      0             0      0           0      0             0      0        300      15          300      15
                          Structure Removal* Using Explosives                           1      1             1 /    1          1      1             2      1           1      1             3      1          3      1             6      2
                          method of Oil Transportation
                               Percent Piped                                      *-**NJL   Nk             NA  / NA            NX  NA               Nk  Nk             HA  Nk               Nk  Nk          02*/     82%         020/     82%
                               Percent Barged                                         NA    NA             NA    NA            Nk  NIL              Nk  Nk             Nk  Nk               Nk  NA            it/    is            it/    is
                               Percent Tankered                                       Nk    NA             NA    Nk            NA  Nk               NX  Nk             Nk  Nk               Nk  Nk          17%/     17%         17%/     17%
                          Shuttle Tanker Traffic (trips)                                0      0             0      0          0      0             0      0           66     3         171        8        66       3           171      0
                          Barge Traffic (trips)                                         0      0             0      0          9      1             22     1           0      0             0      0          9      1           22       4
                          Pipeline Length (km)                                          e      a             a      a          16     a             40     a           56     a         192        a        so       16          240      40
                          Pipeline Displaced Sediments (1,000 m')                     40       2           40       2          0      0             0      0           0      0             0      0        40       2           40       2
                          Bottom Area Disturbances (ha)
                             from rig emplacementa                                      0      2           15       3          27     4             55     11          46     0             92     18       83       14          153      29
                             from structure emplacements                                5   Nk               5   NA            3   NK               6   Nk             3   Nk               9   Nk          10    Hk             19    Nk
                             from pipeline projects                                   26       6           26       6          22     5             30     6           58     14        101        20       106      26          157      30
                          Accidents
                             offshore oil Spills
                               >1 and < 50 bbl                                    ****Nk    Nk             NIL   Nk            Nk  Nk               Nk  NK             Nk  NA               Nk  Nk                Nk             20    Nk
                               >50 and <1,000 bbl                                     Nk    Nk             Nk    Nk            Nk  Nk               Nk  Nk             NA  Nk               Nk  Nk            0      0             1   Nk
                               > 1,000 bbl                                            Nk    NA             Nk    Nk            Nk  Nk               Nk  NA             NA  Nk               NA  Nk            0      0             1   Nk
                             Blowouts                                                   0      0             0      0          0      0             1      1           2      1             4      1          2      1             5      1
                             Diesel and Other Pollutant Spills                          0      0             0      0          0      1             1      1           3      1                    1          3      1             9      1
                          Support Activities
                             Helicopter Trips (1,000 trips)                           12    NA             12    NA            25  Nk               60  Nk             95  Nk           303     Nk          131   Nk             375   Nk
                             Service Vessel Trips                                     400   NA             600   NA       1,200   /Nk            2,600 /NX        6,700    Nk         16,400  / Nk       8,300    Nk         19,500    Nk
                          offshore operational Wastes
                             Drilling Fluids (2,000 bbl)                              69       14          139      21         200/   35         559   /   es     1,092    241         4,121  / 607      2,241    283        4,819     706
                             Drill Cuttings (1,000 bbl)                               16       3           33       5          68 /   9          136   /   21      462        61        996   / 152         546      72      1,164     177
                             sanitary and Domestic Waste        (1,000 ml)            is    NA             20    NK            44  Nk            107    Nk         276     NA           766     NA          335   Nk             892   NIL
                             Produced Waters (1,000 bbl)                           1,415    NA          2,829    NA      13,752    Nk         27,504    Nk     111,036     NA       274,252     NA     126,203    1Nk      304,585     NA
                             Produced sands (1,000 bbl)                                 0   Nk               0   NA            3   Nk               a   Nk             22  Nk               56  Nk          24    /Nk            64    Nk
                          Offshore Air Emissions (1000 tons)
                             Nitrogen oxide                                        2.31     N&          2.15     Nk        4.63    NX            10.75  NA        16.20    Nk          51.58    Nk       23.14    /Nk        64.48     Nk
                             carbon monoxide                                       0.35     Nk          0.32     Nk        0.70    Nk            1.59   Nk         2.46    Nk           7.64    NK          3.51  /Nk            9.55  Nk
                             sulfur oxide                                          0.06     Nk          0.05     Nk        0.12    Nk            0.23   Nk         0.43    Nk           1.12    NA          0.62  /Nk            1.40  Nk
                             Total Hydrocarbon Compounds                           0.71     Nk          0.72     Nk        1.43    Nk            3.57   Nk         5.01    Nk          17.16    NA          7.16  /NX        21.45     Nk
                             Total Suspended Particulates                          0.06     NK          0.05     Nk        0.12    Nk            0.23   Nk         0.42    Nk           1.09    Nk          0.60  /Nk            1.36  In


                                  See @iqura 111.7-2.
                                  Peak year figures for individual subareas may not add to the peak year figure for the total planning area because the peak years for subareas may not occur simultaneously.
                                  Not all development wells classified an oil or gas produce.
                                  information in these categories cannot be revealed by subarea because proprietary information related to projected oil reserves would be exposed.












                                                                                                                          IV-9


             Western Gulf of Merico Offshore Subareas W-1, W-2, and W-3

                 W-1: This subarea is located within the Miocene Trend in Texas and includes most of the Texas Shelf with
             some deep-water areas in the Corpus Christi and Port Isabel Areas. Subarea W-1 is primarily composed of
             Miocene-age sediments, but older sediments (Oligocene-Frio) are encountered close to the Texas coast.
             Drilling can be expected to continue along regional down-to-the-basin faults. The Corsair Trend contains thick
             deposits of Miocene-age sands and extends northeast to southwest through Brazos, Matagorda Island, and
             Mustang Island. Hydrocarbon production is mostly gas, with the greatest potential on the upper and central
             portion of the shelf.
                 W-2: This subarea is located within the Pleistocene Trend in Texas and encompasses mostly shelf and
             upper slope areas offshore Texas and Louisiana. This area is characterized by thick sequences of sand,
             producing gas and condensate, especially along the shelf edge. Shallow accumulations of gas, identified as the
             "Pleistocene Bright Spot Trend" is located in the northern and western portions of Subarea W-2.
                 W-3: This subarea is identified as the Cenozoic Deepwater Trend, which is located to the south and east
             of Subareas W-1 and W-2. This area is characterized by Cenozoic sediments of the middle and lower slope
             in deep water offshore Texas and Louisiana. Miocene potential may exist in this area as the result of turbidity
             currents and submarine channels transporting sediment into deeper waters. Another potential play is the
             western extension of the Flexure Trend in the deep-water areas of East Breaks and Garden Banks. Although
             both oil and gas can be expected, a large portion of this area, similar to Subarea C-4 (Louisiana), is considered
             to have a low probability of producing economic quantities of hydrocarbons.
             2. Description of Offshore Operations and Impacting Factors

                 Exploring for, developing, and transporting the hydrocarbon resources that are developed as a result of
             the proposed actions require a complex and interrelated series of operations that begin with the leasing of
             offshore blocks and continue through postlease seismic/surveying operations; the drilling of exploration wells;
             the installation of production facilities; the drilling of development wells; the movement of hydrocarbons via
             pipelines, barges, and shuttle tankers; the eventual dismantling of the production facilities; and all of the
             offshore movements of personnel and supplies that are needed to maintain these operations. These diverse
             activities can be associated with possible impacts to the offshore (and possibly onshore) resources of the Gulf.
             The following discussions describe the various kinds of offshore activities that could potentially affect the
             environmental and socioeconomic resources of the Gulf of Mexico and identify the resources that could be
             affected. Detailed analyses of the impacts of these activities on environmental and socioeconomic resources
             are contained in Sections IV.D.l. and 2.
                 Tables IV-2 and IV-3 show the magnitudes of the impact factors or agents that are projected to occur in
             the various offshore subareas of the CPA and WPA from the proposed actions under the Base and High Case
             scenarios. These quantities are expressed as the total amount generated over the life of the proposed actions,
             and as a peak-year figure. The peak-year number is the projected occurrence of the impact factor during the
             year when the oil and gas activities associated with the impact factor are at a maximum. Peak-year numbers
             cannot be developed for every impact factor because of the nature of the data that the numbers are derived
             from. An average annual figure can be developed in some cases by dividing the quantity for the total amount
             generated over the life of the proposed action by the expected duration of the activity associated with the
             impact factor (11 years for exploratory activity, 20-year production life for platforms, etc.).

             a. Offshore Infrastructure Activities

             (1) SurveyinglSeismic Operations

                 Seismic operations are conducted from vessels, ranging in length from 20 to 50 m (65-175 ft), that tow an
             array of geophysical instruments. The instruments use an acoustic pulse generated by a string of airguns,
             waterguns, or explosives as an energy source to pinpoint areas with hydrocarbon potential and to identify












                    IV-10

                    hazard conditions such as faulting, potential slide areas, and shallow gas pockets. Seismic activities in the Gulf
                    may affect fish resources, marine turtles, and marine mammals proxiinate to the operations. The degree of
                    affect is highly dependent upon the method used to generate the sound pulse. Airguns have little effect on
                    even the most sensitive fish eggs and no effect on fish or invertebrate larvae (Hanley, 1984; Falk and Lawrence,
                    1973). A task force report on geophysical operations in 1982 found no evidence to suggest that nonexplosive
                    acoustic sources cause injury to marine mammals. They may, however, elicit changes in marine mammal and
                    marine turtle behavior varying from an immediate response (e.g., flight and startle response) to no apparent
                    reaction, depending on the proximity of the seismic pulse (Malme et al., 1984).
                         Seismic operations using explosives have historically taken place around the mouth of the Mississippi River
                    in unconsolidated silty deposits. An environmental assessment is required for all seismic operations that intend
                    to use explosives. Prior to 1989, approximately two applications per year for explosive seismic operations were
                    reviewed by the MMS Gulf of Mexico OCS Region. Since 1989, no plans for explosive seismic operations have
                    been received by the MMS Gulf of Mexico OCS Region (Brinkman, pers. comm., 1991). Because of the
                    hazards associated with explosives and the ability to produce 3D surveys with airgun pulses, the use of airguns,
                    is preferred for Gulf offshore seismic surveys. It is assumed that no seismic activity using explosives win occur
                    as a result of the proposed actions.
                         Prior to August 14, 1990, no records were kept on the amount or location of postlease seismic activities
                    that were conducted on leases because lessees were not required to report nonexplosive activities to MMS.
                    Therefore, no estimates of postlease annual seismic activity is available. The MMS, Gulf of Mexico OCS
                    Region, Office of Resource Evaluation is receiving some reports of activities and is working to ensure that each
                    and every oil and gas company is aware of the need to report all postlease seismic activities.

                    (2) Drilling Rigs and Platforms

                    (a) Exploration and Delineation Phase

                         Offshore exploratory activities are carried out from mobile drilling rigs. Exploration/delineationwells are
                    drilled to determine whether or not economically recoverable resources occur on a lease and to delineate the
                    extent of a reservoir. The exploratory well, casing, and hole are abandoned once the exploration phase is
                    complete. Only rarely is the hole reentered for production purposes.
                         The five most common types of mobile rigs employed for exploratory drilling offshore are submersible
                    drilling rigs, semisubmersible drilling rigs, jack-up drilling rigs, drillships, and drill barges. The preferred
                    environment for each type of mobile drilling rig is highly dependent on its performance at various water depths
                    and in adverse weather conditions. Other important considerations in the selection of a mobile rig are staff
                    support requirements, rig mobilization problems, positioning capabilities, and station maintenance requirements
                    (University of Texas at Austin, 1981). All these factors will play a part in a company's selection of a mobile
                    rig for their exploratory drilling activities.
                         Submersible rigs were among the first types of drilling rigs used for exploratory drilling offshore.
                    Submersible rigs can be floated from one drill site to the next after exploratory drilling is complete; however,
                    they are not easily moved. Once in position over the drill site, their lower hun is flooded until it sinks and rests
                    on the seafloor to support the drilling operation. Because submersible rigs are designed to rest on the seafloor,
                    they are limited to operations at relatively shallow water depths.
                         Semisubmersible rigs are floating platforms used for drilling at deeper water depths. These rigs use
                    dynamic positioning or anchoring to maintain their position over the drill site without the use of bottom-
                    supported structures. Semisubmersible rigs are the most stable offshore drilling unit for deep and rough waters.
                         Jack-up rigs are the most popular bottom-supported, mobile offshore drilling structures. Once the rig is
                    positioned over the drill site, its legs are jacked down until they rest on the seafloor. Jack-up rigs are limited
                    to water depths of approximately 350 ft (107 in) and are difficult to tow; however, they have relatively low
                    initial costs and can perform better than floating rigs under adverse weather conditions.
                         Drillships and drill barges are vessels that function as offshore drilling platforms for exploratory activity.
                    The primary distinction between the two is that drillships are self-propelled while drill barges are not. The












                                                                                                                               IV-11


                advantages of drinships are that they can operate in deep water and they can travel easier and faster to distant
                drill sites. However, they require additional staffing to operate the ship. With increasing industry interest in
                deep-water exploration and development in the Gulf, drillships will likely be used more in the future. This
                document assumes that all exploration and delineation wells in water depths greater than 1,500 ft will be drilled
                from drill ships. At present, industry can drill in water depths up to 2,400 in (8,000 ft), which places few
                limitations on exploratory drilling on the Gulf OCS. (See Section IV.A.2.a.(5) for a discussion of deep-water
                off and gas operations.)
                    Drill barges, on the other hand, do not require a ship crew on board since they are towed to the drill site
                by tug boats. However, drill barges take longer to travel to the drill site location. The primary disadvantage
                of both drillships and drill barges is their limited capability to operate in adverse weather conditions and rough
                waters.
                    This document assumes that the average time required to drill an exploration/delineation well is 45'days,
                and the average well depth will be 4,100 in (13,500 ft). It is further assumed that two to four wells win be
                drilled per field and that the typical rig will drill nine wells/year. During drilling operations, 67 people are
                assumed to be working at the rig site per day. The total number of exploration and delineation wells that are
                projected to be drilled in the CPA and WPA for the Base and High Case scenarios is shown in Tables IV-2
                and IV-3, respectively.

                (b) Development Phase

                    Development wells are usually drilled from fixed platforms, which are equipped with production and
                maintenance facilities on the deck. Development wells are drilled with one (or infrequently two) drilling units
                placed on the platform deck. For analysis purposes, it is assumed that 8-20 wells will be drilled from each
                platform, with an average of about 12 wells. Five percent of the development wells are projected not to
                produce. The average lives of gas and oil wells are estimated to be 12 and 14 years, respectively. The average
                depth of a development well is assumed to be 3,050 in (10,000 ft). During the development well drilling phase,
                it is assumed that 58 people per rig will be employed on site. Tables IV-2 and IV-3 show the numbers of
                development wells projected to be drilled under the Base and High Case scenarios for the proposed actions.

                (c) Production Phase

                    Various kinds of facilities can be installed at a production site. The choice of production facility is
                dependent mainly on water depth and the size of the reservoir to be produced. In water depths less than 460
                in (1,500 ft), fixed platforms rigidly attached to the seafloor will be used. In shallower water depths, where
                production costs are relatively low, the installation of several production structures can often be economically
                justified to produce a reservoir. This document assumes that, in less than 152 in (500 ft), each production site
                will be associated with a platform complex that includes two to three structures. Based on historic platform
                statistics, it is assumed that 68 percent of these structures will be classified as major (defined as having at least
                six completions and two pieces of production equipment) and that 20 percent will be manned (defined as
                having sleeping quarters on the structure). Manned platforms are assumed to have 14 people working on site.
                    At water depths greater than 152 in (500 ft), production expenses increase to the extent that only one
                production facility per field can be economically justified. At these depths, all production structures will be
                major and will serve as a production complex. This document assumes that for water depths up to 304 in
                (1,000 ft) 20 percent of the production complexes will be manned and that all production complexes will be
                manned at water depths greater than 304 in.
                    At water depths approaching 456 in (1,500 ft), traditional platform designs based on the rigid attachment
                of platform legs to the seafloor cannot be used. This document assumes that at water depths exceeding 456
                in, compliant structures, such as tension leg platforms (TLP's) will be used at sites where production will be
                transported via pipeline. All TLP's are considered major, manned structures. This document assumes that a
                floating production system (FPS) will be employed for liquid hydrocarbon development in water depths
                exceeding 456 in and where a production site is farther than 160 km (100 mi) from an existing pipeline system,











                 IV-12


                 making the costs of installing a new pipeline segment prohibitive. The hydrocarbons will be transported from
                 the FPS directly to onshore terminals via shuttle tankers. It is assumed that two FPS's will be. employed in the
                 WPA and one in the CPA for the proposed action.
                     The number of platform complexes projected for the proposed actions can be found in Tables IV-2 and
                 IV-3. The average life of a platform complex is assumed to be 20 years. These tables also provide a
                 breakdown of platform projections by offshore subarea. An in-house MMS analysis of the breakdown of
                 platform projections by water depth was also completed to provide more detailed information on the most
                 likely location of platforms within each offshore subarea. Results from this analysis were used in the
                 assessment of the potential impact of platforms on offshore environmental resources. However, details of the
                 analysis cannot be revealed in this document due to the proprietary nature of the information.

                 (3) Stmcture Removcds

                     Lessees are required to remove all structures and underwater obstructions from their Federal OCS leases
                 within one year of the lease's relinquishment or termination of production. Plastic explosives sever the
                 conductors and pilings 5 m below the seafloor and are used because of the strongly overbuilt condition of
                 multileg offshore structures that must withstand probable hurricane conditionsover an average: 20-year lifespan.
                 Explosive platform removals may adversely affect marine mammals and turtles in proximir@ to the removal.
                 The concussive force of the explosives is lethal to most fish associated with the platform. Those species that
                 have internal air chambers (swim bladders), are demersal, or are in close association with the platform being
                 removed are certainly killed (Caillouet et al., 1986). Within the past decade, stocks of dernersal reef fish (red
                 snapper) have precipitously declined in the Gulf of Mexico. There is concern over a possible connection
                 between the decline and explosive platform removals. To examine this issue of concern, in 1992 MMS funded
                 an interagency study with NMFS to assess fish mortality from explosive platform removals. This study win
                 further attempt to relate the role of red snapper mortality from platform removals to the status of reef fish
                 stocks in the Gulf (USDOI, MMS, 1990a).
                     The MMS has issued strict guidelines for explosive platform removal to offshore operators in order to
                 eliminate potential harm to endangered marine turtles and marine mammals. These guidelines include daylight
                 detonation only, staggered charges, placement of charges 5 m below the seafloor, and pre- and postdetonation
                 surveys of surrounding waters. It is assumed that these guidelines will be followed during the removal of all
                 platforms installed as a result of the proposed actions.
                     All platforms installed as a result of the proposed action will be removed by the end of the year 2027, 35
                 years after the sale. Over that period, it is assumed that 80 percent will be removed by explosives only in water
                 depths less than 455 m due to engineering differences between fixed platforms in deep-water systems. (See
                 Section IV.A.2.(a)(5) for further information regarding deep-water activity.) The 80 percent figure is based
                 on an analysis of platform removal records at MMS (Shaw, personal comm., 1991). Use of offier nonexplosive
                 methods, such as mechanical cutters to sever pilings of multileg structures, are too hazardous to underwater
                 workers and are ineffective. However, a number of offshore operators and engineering firms in the Gulf are
                 presently engaged in development of new technology and removal methods alternative to explosives.
                     It is assumed that during the peak year, five platforms will be removed from the CPA. and one Will be
                 removed from the WPA using explosives as a result of the proposed actions (Tables IV-2 and IV-3). Annual
                 rates for all removals (including nonexplosive) from the CPA range from zero to six in the CPA and from zero
                 to one in the WPA_ It is assumed that these structures will be removed during the last 12 years of the life of
                 the proposed action.

                 (4) WorkoverlAbandonment Activities

                     Workover operations consist of work conducted on wells after the initial completion for the purpose of
                 maintaining or restoring the productivity of a well. Tubing can be pulled and the casing at the bottom of the
                 well pumped and washed free of sand that may have accumulated. Other examples of workover operations
                 are acidizing the perforated interval in the casing, plugging back, squeezing cement, milling out cement, jetting












                                                                                                                         IV-13


             the well in with coiled tubing and nitrogen, setting positive plugs to isolate hydrocarbon zones, etc. Workover
             operations can require the use of a jack-up rig barge. Operations, which can take from a few days to several
             months to complete, occur in mature oil and gas areas and, thus, are common in the Gulf of Mexico. In 1990,
             about 4,200 completions, workovers, and plugging/abandonment operations took place, with about 2,400 of
             these estimated to require rig emplacement. About 20 percent of all workover operations require a jack-up
             rig or other major rig. All plugging and abandonment operations conducted when the wen is finished
             production require rig activity. Worldwide rig activities show that workover rig activities accounted for 15
             percent of rig drilling operations from 1986 through 1990 (The Offshore International Newsletter, 1991).
                 The following are assumptions about workover activities occurring in association with the proposed actions:
             It is assumed that each development well will require one to three workovers, averaging 1.5 workover
             operations per development well. One plugging/abandonmentoperationwflI be required per completion well.
             Using these numbers, estimates of workover operations from the proposed actions are 375 and 780 workovers
             in the CPA and 165 and 405 workovers in the WPA, for the Base and High Cases, respectively. Well
             abandonment operations are equal to the number of development wells emplaced, i.e., 250 and 520 in the CPA
             and 110 and 270 in the VVPA, for the Base and High Cases, respectively. Operations will average 10 days and
             will require support services similar to support provided during well development. Twenty percent of all
             workovers will require rig activity.
                 Workover operations can result in water quality impacts associated with the improper discharge of
             workover fluids used to treat the well and can result in blowouts and oil spills if drilling occurs. Nineteen
             percent of historic blowouts on the Gulf of Mexico OCS have been from workover operations. Secondary
             impacts can occur from support activities needed during workover operations. There will be some increase
             in helicopter traffic, service vessel trips, and employed personnel on the platform. These increases are not
             included in the numbers of trips provided in the tables.

             (5) Deep-water Activides

                 This section presents information about the general status of deep-water operations and technological
             developments in the Gulf of Mexico. The development of the OCS program in the Gulf has seen the
             movement of industry activity from tracts close to shore in shallow water to ever deeper prospects, some of
             which are located 150 mi or more from the coast Future activities in the Gulf are likely to emphasize more
             and more deep-water projects. Specific assumptions about aspects of deep-water development that are relevant
             to the analysis of potential impacts to Gulf resources are presented in Section IV.A.2.a.(2) for each phase of
             operation.
                 Presently, the offshore oil and gas industry is establishing the technology required for producing natural
             gas and oil resources from the deep-water areas of the Gulf of Mexico. For the past half-century the majority
             of offshore developments have been focused on the continental shelf, in water depths less than 200m(600 + ft).
             Future developments in the northwest and north-central Gulf of Mexico will move from the continental shelf
             area to the continental slope and margins. Slope and margin technology has a unique set of problems
             associated with extreme water depths, bottom topography, and bottom conditions. As far back as 1985,
             industry experts indicated that the existing technology could be extended to approximately 8,000 ft without the
             need for major technological breakthroughs.
                 Recently, record-setting developments and giant field discoveries set the stage for deep-water activities in
             the Central Gulf of Mexico. Shell's "Bullwinkle" facility (1,350 ft of water) in Green Canyon Block 65 went
             into production in August 1991. Several options for producing Shell's recent "Mars" prospect in Mississippi
             Canyon Block 763 (3,100 ft of water) are being considered, including the use of tension leg platforms, floating
             and subsea production systems, and compliant towers. Production from Conoco's Joliet and Marquette (Green
             Canyon Block 184) fields is being processed from a central production platform on adjacent Green Canyon
             Block 53, located in 470 ft of water. Recently, Freeport McMoran set a new record for the world's tallest 4-
             pile platform when its Crystal platform was installed in Mississippi Canyon Block 365 in water depths exceeding
             600 ft.












                   IV-14

                        In the Western Gulf of Mexico, deep-water drilling is currently confined to two program; being carried out
                   in Garden Banks and to a third in the relatively unexplored Keathley Canyon area. In the Garden Banks area,
                   two wells have been spudded in water depths of 2,850 ft; whereas in Keathley Canyon, BP is currently
                   operating in water depths exceeding 5,800 ft. Shell's billion dollar Auger field development in Garden Banks
                   Block 426 (2,680 ft of water) will become the deepest water production facility in the worLd.
                        According to the Federal Government's Office of Technological Assessment (1985), a number of
                   technological areas are critical in deep-water petroleum development These areas include structural design;
                   developing techniques for installation, maintenance, and repair of structures; drilling, well control, and
                   completion; and technologies for support operations. To continue operating in these new environments, the
                   use and development of new technologies is needed. Several of the newer technologies under consideration
                   are discussed below.


                   Stmaures

                        With regard to exploratory drilling, the offshore industry has a fleet of drillships and sernisubmersibles
                   capable of drilling in water depths greater than 3,000 ft and, in some instances, in water depths up to 7,500 ft.
                   Technological advances that made drillships capable of operating in deep-water areas include the development
                   of dynamic positioning and advanced reentry systems.
                        Today, several concepts for extending the depth of production systems are being employed in the Gulf of
                   Mexico and worldwide. These include the use of the guyed and buoyant towers, tension leg platforms, and
                   subsea production systems. With the exception of the subsea completion systems, all these structures are
                   termed "compliant structures," which move slightly with wind, waves, and current forces. Conventional
                   structures are designed to resist these forces.
                        The use of these various structure types will depend on several variables--cost, density of wells within
                   proximity to the structure, bottom conditions, proximity to existing infrastructure, and reservoir and well
                   characteristics. A compliant tower is preferred when developing an area with a high number of wells in close
                   radius to the structure. A tension leg, platform, or another form of buoyant system is better suited to situations
                   in which a field can be developed with fewer wells. The greatest limiting factor is the cost of platform
                   structures. In minimizing the size of structures to cut costs and thus, restricting the capacity, of production and
                   process facilities, the production period is lengthened.
                        Exxon installed the first "unconventional"structure in the Gulf of Mexico, which consisted of a guyed tower
                   to develop its Lena Prospect (300 m) in Mississippi Canyon. This design can be used in water depths up to
                   600-750+ m (2,000-2,500 ft). In the late 1980's, Conoco used the first tension leg platform in the Gulf to begin
                   production of it's Joliett field (500 ft of water). Shell is presently moving forward with it's planned installation
                   (1993) of a 31-slot tension-leg platform on it's Auger discovery (2,680 ft of water). Regarding subsea
                   completion technology in the Gulf, work is progressing on Exxon's Zinc-Alabaster project (1,500 ft of water)
                   in Mississippi Canyon. This half-billion dollar project will require the largest multi-well satellite subsea template
                   (Zinc gas field) yet seen in the Gulf of Mexico. This template will be tied back to a new 18-slot platform
                   (Alabaster gas/ofl field) and some six miles away in 468 ft of water. Texaco is evaluating subsea development
                   options to tap gas reserves on its Shasta Prospect in Green Canyon (900-1,500 ft of water). Texaco has gained
                   considerable experience with this technology in the North Sea.

                   Pipelines
                        According to R.J. Brown and Associates, considerable research is being expended for the installation of
                   gas and oil transport systems in deepwater areas, As of late 1990, the deepest project was in Placid's Green
                   Canyon Block 29, in which flowlines were installed to a template and wellhead in water depths up to 2,4.00 ft.
                   Now, the industry is looking beyond the 2,400-ft mark established by the Placid project. As pipeline
                   installations are being conducted in deeper water depths, the structural qualities of the pipe for re@isting
                   collapse are becoming more important There is a depth restriction, which depends upon. the design ciiteria
                   used, and unless new approaches evolve, methods of installation will be limited in terms of pipe diameter, wan
                   thickness, and depth. For fixed wall thickness pipes, the larger the diameter, the shallower the water depths












                                                                                                                           IV-15


              in which it can be installed without additional measures to prevent collapse. One technique employed, yet
              restricted to towing techniques, requires pressurization of the pipe to prevent collapse, thus increasing the
              depth at which installation may occur.
                  The conventional laybarge has a long history of pipeline installations with sizes ranging up to 56 inches and
              smaller fines laid at depths in excess of 1,000 ft. A more recent innovation has been the development of a
              high-performance, dynamically positioned lay vessel, which employs a new "J" lay technology. This has
              considerable promise for smaller diameter piping in water depths up to 5,000 ft. New towing techniques are
              also being used for deeper water prospects. The use of these techniques began in the late 1940's when strings
              of pipe were made up onshore and towed both on the surface and bottom. Today it is feasible to construct
              pipelines onshore, in excess of 10 km (6 mi) in length, and to tow these from the coast to deep-water sites.
              It is also technically feasible to install and connect single or bundled pressurized lines up to 24 inches in
              diameter and to install at depths up to 5,000 ft by the use of such towing techniques.

              Floating P@oduction Systems

                  The use of tanker-based Floating Production, Storage, and Offloading systems (hereafter referred to as
              floating production systems, or FPS's) are thought to be an economical solution for satisfying industry's needs
              in the deep-water areas (up to 3,000 ft of water) of the Gulf of Mexico. Such a facility would be complete,
              with equipment ranging from wellheads, production risers, and well control equipment to a tanker (75,000-
              150,000 dead weight tons) (dwt), mooring, and tanker offloading systems. The availability of crude sales lines,
              environmental conditions, and travel rates for shuttle or export tankers will determine the unit's minimum
              storage and tanker size. Such a system has several advantages over a semisubmersible based floating
              production system, in that an FPS would have more deck space and deck loading capabilities, stability, and oil
              storage capacity of between 1 and 2 million bbl (MMbbI). To date, about 12 tanker based FPS's have operated
              worldwide, with none encountering major safety problems or significant oil spills.

              b. Offshore Transport of Oil and Gas

                  Transportation of petroleum hydrocarbons to onshore terminal facilities in the Central and Western Gulf
              of Mexico historically has relied on an ever-expanding pipeline network. Along with the movement of oil and
              gas/condensate through pipelines, a small percentage of oil has traditionally been barged from shallow water
              areas to onshore oil terminals. Because MMS projects that leasing in deep-water blocks not located in
              proximity to the existing oil-pipeline network will occur as a result of the proposed actions, future shuttle
              tankering of oil is projected to occur in both the CPA and the WPA_ Tables IV-2 and IV-3 present projected
              percentages of oil transported via pipeline, barge, and shuttle tanker and the numbers of trips expected in
              support of the proposed actions. Tables IV-4 through IV-6 provide information on the volumes of oil making
              landfall in the various onshore subareas and on the locations of offloading operations. The following
              discussions provide further information supporting the projected transportation scenario, identify the potentially
              affected resources, and describe the general impacts associated with each method of transport.

              (1) Pipelines

                  Pipelines are now used as the primary means of oil/condensate movement and the sole means of gas
              transportation in the Gulf. Although MMS anticipates the usage of shuttle tankers to transport oil produced
              on the OCS in the future, pipelines are still expected to account for 98 percent and 82 percent of the liquid
              hydrocarbons transported in the CPA and WPA, respectively, during the life of the proposed actions (Tables
              IV-2 and IV-3).
                  Pipelines in the Gulf include trunkline and gathering line systems. Gathering lines, typically short segments
              of small diameter pipelines, transport production from a structure to a tie-in with an existing pipeline system.
              This document assumes that 8 km (5 mi) of gathering lines will be installed with each production facility
              associated with the proposed actions.




















                                                                                                                   Table rV-4

                                                                                 Onshore Scenario Information Related to Sale 142 for the Years 1993-2027

                                                                                                                           Onshore Subarea*
                                                                                     -------------------------------------------------------------------------------------------
                                                                                                C-1                                C-2                               C-3
                                                                                      Base Case         High Case      Base Case           High Case     Base Came          High Case
                                                                                     ---------------------------       ---------------------------       ---------------------------
                                      Onshore (Total    Peak Year)
                                      ----------------------------


                                      Oil Landings
                                        Pipeline Transported Oil (KMbbl)                 0 /    0          0     0       lie      6        261    13       19       1        42  /    2
                                        Shuttle Tanker offloadings                       0 /    0          0     0         0      0          0      0        2      1          5 /    I
                                        Barge offloadinqs                              39  /    2        89      4         19     1        45       2      17       1        40  /    2
                                      Onshore oil Spills
                                        >1 and <50 bbl                              -NA      Nk          NA    Nk          Nk  Rk          NA     Nk       NA    NA          NK     Nk
                                        >50 and < 1,000 bbl                            NA    NA          NA    Nk          Nk  Nk          Nk     Nk       Nk    NA          NJL    Nk
                                        > 1,000 bbl                                    Nk    NA          Nk    NA          NA  Nk          Nk     Nk       Nk    Nk          NJL    Nk
                                      Support Activities
                                        Helicopter Coastal Crossings (1,000's)         37    NA          62    Nk          84  NA          142    Nk       74    NA         125     Nk
                                        Service Vessels
                                          Landings                                  6,200    Nk       10,900   NA      6,300   NA       11,000    Nk     3,900   NA        6,900    NA
                                          Bilge Water Discharged (MMliter)             20    NA          35    NA          20  NA          35     NA       12    NA          22     Nk
                                      Onshore Disposal of Offshore Wastes
                                        Produced Sands (1,000 bbl)                  -**Nk  / Nk          NA    Nk          Nk  WA          NA     Nk       NA    NA          NJL    Nk
                                        Produced Waters (1,000 bbl)                      0 /    0          0     0         0      0          0      0   34,071   Nk       70,821    Nk
                                        Drilling Fluids (1,000 bbl)                 ***Nk  / NA          NA    Nk          Nk  NK          NA     Nk       Nk    NA          Nk     Nk


                                                                                     -------------------------------------------------------------------------------------------
                                                                                         C-4                               W-2                               Total
                                                                                      Base Case         High Case      Base Case           High Came     Base Case          High Case
                                                                                     ---------------------------       ---------------------------       ---------------------------
                                      Onshore (Total / Peak Year)
                                      ----------------------------


                                      Oil Landing&
                                        Pipeline Transported oil (Kxbbl)                 0 /    0          0     0         0      0          0      0      137   NA         303     NA
                                        Shuttle Tanker offloadinqs                       0 /    0          0     0         0      0          0      0        2      1          5      1
                                      O.:harq: offloadinqs                               0 /    0          0     0         2      1          4      1      77       4       178       8
                                          or oil Spills
                                        >1 and <50 bbl                                 Nk    NA          NA    NA          NA  NA          NA     NA     .*<10      1       <10       1
                                        >50 and < 1,000 bbl                            Nk    NA          NA    Nk          NA  Nk          NA     NA         0      0          0      0
                                        > 1,000 bbl                                    Nk    NA          NA    Nk          NA  Nk          Nk     Nk         0      0          0      0
                                      Support Activities
                                        Helicopter Coastal  Crossings (1,000's)          6   NA.         10    NA          4   Nk            7    NA       206   NA         347     NA
                                        Service Vessels
                                          Landings                                     500   NA          Soo   Nk        700   Nk        1,100    NA    17,600   NA       30,800    Nk
                                          Bilge Water Discharged (MI41iter)              2   NA            3   Nk          2   Nk            3    Nk       56    NA          98     Nk
                                      Onshore Disposal of offshore Wastes
                                        Produced Sands (1,000 bbl)                     NA    NA          NA    Nk          NA  NA          NA     Nk       69    NA         154     Nk
                                        Produced Waters (1,000 bbl)                      0      0          0     0         0      0          0      0   34,071   NA       70,821    Nk
                                        Drilling Fluids (1,000 bbli                    Nk  I NA          N&    Nk          Nk  X&          Nk     NA       7AA   102       1:333    153


                                           See Figure IV-1.
                                           AAsumptions about number   of oil spill occurrence@   are derived from  historical trends but are  not based on statistical analyses.
                                           Data are not shown by subarea because of statistical uncertainties.

















                                                                                                                Table IV-5

                                                                            Onshore Scenario Information Related to Sale 143 for the Years 1993 - 2027

                                                                                                                       Onshore Subarea-
                                                                                      -------------------------------------------------------------------------------------------
                                                                                                  W-1                                 W-2                                 C-1
                                                                                      Base Case          High Case       Base Case           High Case       Base Case           High Case
                                                                                      ---------------------------        ---------------------------         ---------------------------
                                     Onshore (Total / Peak Year)
                                     ----------------------------

                                     Oil Landings
                                       Pipeline Transported Oil (mmbbl)                 14  /    1           36/    2         23/   1           60 /   3         0      0           0      0
                                       Shuttle Tanker offloadings                       31  /    2           80/    5         28/   2           73 /   4         5      1           13     1
                                       Barge offloadings                                  0      a           0      0         7     1           le     3         2      1           4      1
                                     Onshore oil spills
                                       >1 and <50 bbl                                ... NA      NA          Nk     Nk        NA    VA          Nk     Nk        NA     NA          NA     Nk
                                       >50 and < 1,000 bbl                              NA       NA          Nk     Nk        NA    VA          Nk     NJL       Nk     NA          NA     NA
                                       > 1,000 bbl                                      Nk       NA          Nk     Nk        NA    FA          Nk     Nk        NA     NA          Nk     Nk
                                     Support Activities
                                       Helicopter Coastal crossings (1,000's)           23       NA          67     Nk        28    VA          80     Nk        22     NA          63     NA
                                       service Vessels
                                         Landings                                    2,500       NA      5,900      NA   3,500      NA      8,100      NA    1,800      NA      4,300      NA
                                         Bilge Water Discharged (Mmliter)                 8      NA          19     NA        11    NA          26     NA        6      NA          14     Nk
                                     Onshore Disposal of Offshore Wastes
                                       Produced Sands (1,000 bbl)                    -**VA       Nk          NA     NA        NA    NA          NA     NA        Nk     NA          NA     NA
                                       Drilling Fluids (1,000 bbl)                   -NA         NA          Nk     NA        NA    NA          Nk     Nk        NA     NA          NA     NA


                                                                                      -------------------------------------------------------------------------------------------
                                                                                                  C-2                                C-3                                Total
                                                                                       Base Case          High case      Base Case           High Case       Base Case           High Case
                                                                                      ---------------------------        ---------------------------         ---------------------------
                                     Onshore (Total / Peak Year)
                                     ----------------------------

                                     Oil Landings
                                       Pipeline Transported oil (mmbbl)                 3 /    <1            8 / <1           0 /   0           0      0      40        1       104 /      4
                                       Shuttle Tanker Offloadings                       0 /      0           0 /    0         2 /   1           5      1      66        3       171 /      8
                                       Barge offloadings                                0 /      0           0      0         0     0           0      0         9      1        22        4
                                     Onshore oil spills
                                       >1 and <50 bbl                                   NA  /    NA          NA     NA        NA    NK          Nk     NA     <10       1       -*<10      1
                                       >50 and < 1,000 bbl                              NA  /    NA          NA     NA        NA    NA          Nk     NA        0      0           0      0
                                       > 1,000 bbl                                      NA       NA          NA     NA        NA    NA          NA     NA        0      0           0      0
                                     Support Activities
                                       Helicopter Coastal   Crossings (1,000's)           0      NA          0      NA        0     VA          0      NA        73     NA       210  /    NA
                                       Service Vessels
                                         Landings                                       500      NA       1200      NA        0     WA          0      NA    8,300      Nk     19,500 /    NA
                                         Bilge water Discharged (14Mliter)                2 /    NA          4      NA        0     WA          0      Nk        26     NA          62/    Nk
                                     Onshore Disposal of offshore Wastes
                                       Produced Sands (1,000 bbl)                       NA  /    NA          NA     NA        NA    NA          Nk     NA        24     NA          64/    Nk
                                       Drilling Fluids (1,000 bbl)                      NA  /    NA          NA     Nk        NA    NA          Nk     NA     406       51       872  / 128


                                          See Figure IV-1.
                                          Assumptions about number of oil spill occurrences are derived from historical trends but are not based on statistical analyses.
                                          Data are not shown by subarea because of statistical uncertainties.

















                                                                                                                                                                                                                                                     00





                                                                                                                                           Table IV-4

                                                                                            Wat-y Usage by OCS-Ralated Navigation Associated With Sale. 142 and 143 for the Years 1993-2027

                                                                                                                                 Harbor of                               Number of                        Number of
                                                                                                             4 OCS           Service Vessel Landings                     Serge Offloadiq.             Shuttle Tanker Offloadings
                                                                                                             Us.  -       (Sal. 1421          (Sale 143             (sale 143)      (Sale 143)           (Sale L42)     (Sale 143)
                                         Coastal                                                              Blao      Be"      B gh         R..      High       B.::      High    Ba::   High      Base     High    Be"      Big
                                         Subars.      Watervay Used                 Service Base/Torminal     CA"       CA"      Case         case     Case       CA        Case    CA     Came      Case     Case    Case     Case
                                         C-1          Calcasieu Ship Channel                                  <0.10                                                                                                      5       13
                                                                                        Case                            3,870    6,770        1,140    2,480
                                                                                        Lak. Charl*.                                                                    is       36       1       3
                                                                                        .Lbb.t@                                                                                  is       0       1

                                                      rresh@ter Bayou                                         <0.11
                                                                                        Intracoastal City               21120    3,720          630    1,47*
                                                                                        Kept"                               so        So          10        30
                                                      mormentan Navigation Channel                            <0.11
                                                                                        grand Ch..ir                      140         250         40        100
                                                      Vo.silion Bay/Baym ?"he                                   1.9%
                                                                                        Loci a                              30        so          10        30
                                                                                        Weak. Island                                                                    is       36
                                         C-2          Atchafalaya Hiver                 Asolia                  0.9%      110         200         to        20
                                                                                        =Boeuf                              60        too         0         10
                                                                                               k                            10        too         0         10
                                                                                        Freshwater City                   .0          200         to        20
                                                                                        = city                          3,590         290       290         '90          6       13
                                                    Bay- tafouraho/Bell. Pa..                                 1.2%
                                                                                        rourohon                          120      1,080          50        120
                                                                                        Leavill.                          34.         590         So        60

                                                    Bouna/Caillom/Terraboune                                  2.24
                                                                                        Dula.                             7:0      113,80         60        150
                                                                                        B-                                5 0         9 0         50        1. 10
                                                                                        Theriot                             10        too         -0        to
                                                                                        Gibe-                                                                                    13
                                                                                        Cocodrie                                                                                 is

                                         C-3        Barataria Waterway/LaLoutze                              <0.14
                                                                                        Grand 1.1o                        330         530

                                                    Kiss. River Gulf Outlet                                  <0.14
                                                                                        Hopedale                            50        too
                                                    Ki... River Pa....                                       <0.14                                                                                     2         3      2        5
                                                                                        Venice                          3,510      6,150
                                                    Espire Waterway                                           0.64                                                               40
                                                    La Loutro/St Malo/Yacloskey         Expire                0.5%                                                      17
                                                    Kiss. River/Harvey Canal
                                                                                        Harvey                              so        100
                                         C-4        Bayou LaBatre                                            <0.14
                                                                                       Day= LaBatre                         30        50
                                                    Mobil. Bay                         Mobile                <0.11        370         640
                                                                                       Theodore                             30        50
                                                    Pacaqmla/Bayou Camotte                                   <0.14
                                                                                       P .... goula                         60        100































                                         Table, XV-6. Wato@y Usage by OCB-Relatod Navigation AmccLatod With "lea 142 and 143 fOX the Toaro 1993-2027 (contiumd)


                                                                                                                                  Number of                               Namber  of                       Nuffbor of
                                                                                                              S Ocs           "wico Vassal T-nd'      a                  3k.90 OEf,.dn,.               Shuttle, Tanker OffloadLoge
                                                                                                              UMAq*                            (Salo  143L           (Salo 142)       ("10 L45)          (Salo 142)     (Salo 143)
                                         Coastal                                                                Base             &4:4b        Bass     8 h         B."       High     Bass, High      Sam     Nigh     Base   RLgb
                                         Sub&"&       Wato@y Used                    Soxvice Base/Torminal      Cam     Cam        Cam        Cam       Cam       Cam        Cam      Cam   CA"       Cam     CA"      Cam    Cam

                                         W-L         A.-a Pass                                                <0.11
                                                                                       P-t      .-m                                               70        170
                                                                                       1.91-i'le                                                  SIO       11900
                                                                                       R-kp-t                                                     70        170
                                                     Drama Santiago Pam                                       <0.1%
                                                                                       Port I-bol                                                 ISO       ISO

                                                     Corpus Christi Ship Channel                             <0.11                                                                                                     U      00
                                                                                       C..p- Christi                                              70        170
                                                     Ma@qorda Ship Chanoel                                   1O.L%
                                                                                       Port O'Connor                                           1,250        2,930
                                                     Port Mansfild Ct                                        <0.1%
                                                                                       Port Mansfiold                                             70        L70

                                         W-2         rreoport Raxbor chsoool                                 <0.1%                                                                                                      9     23
                                                                                       r rwo Port                          160         280        830       1,960
                                                     BoostM/Galv Ch@l                                        <0.1%                                                                                                     L4     36
                                                                                       S-f.id.                               20          40       120       280
                                                                                       Gal-t-                              L:O         340     L.010        213:0                     4     10
                                                                                       Pali- Island                           0        140        420       9 0
                                                     Sabina Pass Ship Channel          Sabi- Pa..            <O.Lt         200         360     1,070        2,320                                                       5     13
                                                                                       Port krthar                                                                   2       4        3       8

                                                                                                             TOTAL    L7,600      30,SSO    8,300     19,500         77    178        9     22         2        5      66     17L











                  IV-20


                       Trunklines are large diameter pipelines designed to transport substantial volumes of production from
                  offshore fields to onshore terminals or to a tie-in with an existing trunkline. Trunklines are long and are
                  typically designed to transport production from several offshore leases. Because of the large expense of
                  installing a trunkline, it is assumed that production from more than one lease sale is needed to economically
                  justify its installation. It follows, therefore, that no new trunklines will be installed under either the Base or
                  High Case scenarios associated with the proposed sales. (New trunklines are projected under the Total OCS
                  Program scenario and are described in Section IV.B.l.b.(2)).
                       As of December 1990, the total length of existing pipelines (including gathering lines and trunklines) in the
                  Gulf of Mexico was 28,595 kni (17,757 mi) in the CPA and 4,654 kni (2,892 mi) in the WPA (Tables IV-7 and
                  IV-8). This existing pipeline system provides a network for the gathering lines installed as a result of the
                  proposed action to tie into. Under the Base and High Case scenarios, respectively, 240 and 400 km (150 and
                  303 mi) of new offshore gathering lines will be installed in the CPA, and 80 and 240 km (50 and 150 mi) in
                  the WPA (Tables IV-2 and IV-3). Tables IV-2 and IV-3 also show the distribution of projected new pipelines
                  by offshore subareas. No new pipeline landfalls are projected under either the Base or High Case scenarios.
                       The proposed scenarios include increased levels of activity in water depths exceeding 300 m, compared to
                  earlier periods of OCS development. With the increasing trend toward leasing and development in deep-water
                  areas of the Gulf, pipeline installation projects are extending into water depths that will require new
                  technological innovations. Section IV.A-2.a. (5) discusses some of the technological issues associated with deep-
                  water activities in the Gulf.
                       One approach to deep-water installation projects has been to assemble long lengths (up to 10 km, or 6 mi)
                  of pipe onshore and then to tow the assembled pipe to the production site. This approach has already been
                  used successfully for a project in the Green Canyon Area and is being planned for a new pipeline project in
                  the Mississippi Canyon Area. Onshore, a private beach on Matagorda Island has been used to assemble the
                  pipe in both cases. Under the proposed action scenarios, it is assumed that some deep-water gathering line
                  projects will use pipe towing from shore-based facilities and that the same shore base on Matagorda Island will
                  be used to assemble the pipe segments. The MMS requires that an Environmental Assessment and a Hazards
                  Survey be conducted along the tow route to determine whether or not any resources near the route could be
                  affected by the towed pipeline segment. Based on information obtained from the completed tow project to
                  Green Canyon, it is assumed that the impact area of the pipe will be limited to the diameter of the pipe and
                  that the tow will maintain a plus or minus 30-m accuracy with respect to the proposed route.
                       Impacts from the installation of offshore pipelines include effects on water quality, benthic communities,
                  archaeological sites, and fishery resources. These impacts could occur as a result of the resuspension of bottom
                  sediments during the pipeline installation process, from mechanical damage to benthic and archaeological
                  resources from pipelaying activity, or from exposed pipelines and valves at the seafloor snagging with fishing
                  nets.


                  (2) Oil Barges

                       Barging oil, rather than transporting it to shore by pipeline, has been occurring to a small extent in the
                  OCSwaters since the 1950's. An operator will usually decide at the start of production whether or not to barge
                  the oil. The decision to barge rather than to pipe is contingent on a number of factors--the location of the
                  lease block, the amount of production expected to occur, the proximity to existing pipelines, and the rates
                  charged by pipeline companies. Barging is often faster and cheaper than the time and expense for laying a
                  new pipeline. Some oil companies simply prefer barging. All of the lease blocks where barging is taking place
                  are located fairly close to shore. Barging is expected to remain an activity in waters closest to State waters.
                  It is assumed that barging new oil resources developed as a result of the proposed actionswill only occur in
                  offshore areas where barging currently occurs. The following discussion accounts only for barging operations
                  from offshore platforms to onshore terminals located along the Texas and Louisiana coasts. Barging is also
                  associated with transporting the oil from the terminal to the refinery. These secondary barging operations are
                  discussed in Section IV.A.3.b.












                                                                                                                             IV-21


                    Historically, about 3 percent of oil produced in the Gulf of Mexico has been barged to shore. However,
                because the proposed action scenarios project a large percentage of leasing in deep waters, projections of oil
                barging occurring from the proposed actions are only slightly greater than 1 percent in the CPA and less than
                1 percent in the WPA_
                    Tables IV-2 and IV-3 provide assumptions of the percentages of oil barged and the estimated number of
                barge trips from each of the offshore subareas projected for the Base Case and High Case scenarios for
                proposed Sales 142 and 143. In the CPA, 77 and 178 barge trips are estimated to occur due to the Base Case
                and High Case, respectively, with 4 and 8 trips occurring during the peak year. Most of the barging activity
                in the CPA will originate from Subarea C-1 and C-3. In the WPA, only 9 and 22 barge trips are expected to
                occur due to the Base Case and High Case, respectively, with only one trip occurring during the peak year for
                the Base Case. All of these trips will originate in W-2.
                    The capacity of barges used for the transport of OCS-produced oil can range from 5,000 to 80,000 bbl.
                Barges collect oil from a number of platforms before returning to shore. Barges typically stay offshore for as
                much as one week from the time they leave their docks.
                    The types of potential impacts from barging operations are similar to those from tankers, that is, primarily
                oil pollution and loss of property and life caused by collisions. Unlike tankers, barges in dedicated service do
                not clean their tanks between loadings, do not require ballasting waters, and do not accumulate large amounts
                of bilge waters contaminated with fuel oils. Barges, however, have more oil spills than tankers; this is probably
                because of the greater amount of barge traffic. An examination of U.S. Coast Guard statistics on spill incidents
                occurring in all navigable waters of the U.S. was compiled for the years 1984-1986 (USDOT, CG, 1989) and
                shows that there are about twice as many barge spills as tanker spills. During 1984-1986, an average of 508
                barge spills per year spilled an average of 63,980 bbI per year. In comparison, there were only 206 tanker
                spills, spilling an average of 95,975 bbl per year. Although the quantity spilled from tankers appears to be
                more, the data is skewed by one very large spill that occurred in 1985. If only 2 years of tanker spill data are
                examined, an average of only 16,197 bbl are spilled per year. The larger percentage of spillage from barges
                is likely attributed to spills occurring at terminals. See Section IV.C.1. for projections of barge spills related
                to the proposed actions.

                (3) ShuUle Tankers

                    Historically, there has been no shuttle tankering of oil in support of the OCS oil industry in the Gulf of
                Mexico. However, because of projected leasing in deep water and far from the existing pipeline network,
                assumptions on the use of shuttle tankers are considered in the impact analyses. Tankering is projected to take
                place outside of a 100-mi radius from the existing pipeline network. A combination of tankering and pipelining
                is not assumed to occur from the same production facility. The oil will be loaded at the production site,
                projected to be a tanker-based floating production, storage, and offloading system, and brought directly into
                a major terminal/port system to be offloaded. Section IV.A-3.b.(3) discusses the locations of the offloading
                terminals and/or major ports projected to serve oil tankering operations associated with the proposed actions.
                    Shuttle tankers used for OCS operations in the Gulf are expected to have capacities ranging from 20,000
                dwt (133,000 bbl) to 50,000 dwt (333,000 bbl). The specifications for a typical 20,000-dwt tanker are 172 m
                (565 ft) in length by 27 m (89 ft) in breadth with a draft of about 10 m (34 ft).
                    Less than I percent of oil produced in the CPA as a result of Sale 142 (Base Case) is estimated to be
                transported via shuttle tankering (Table IV-2). Under the Base Case for proposed Sale 142, two shuttle tanker
                trips are expected to occur sometime during the 20-year life of the FPS's. These trips will originate in offshore
                Subarea C-3 and will offload at the Mississippi River Port system. Under the High Case, five trips are expected
                (Table IV-2).
                    Seventeen percent of the oil to be produced in the WPA as a result of Sale 143 (Base Case) is estimated
                to be transported to shore via shuttle tankering (Table IV-3). Under the Base Case of proposed Sale 143, 66
                trips are expected. These trips will originate from Subarea W-3 and will offload at five major port areas in
                both Texas and Louisiana. Under the High Case, 171 trips are expected.











                 IV-22

                     The primary environmental concern associated with shuttle-tanker operations is potential oil pollution,
                 which can occur as a result of tanker accidents or operational discharges. Collisions, another concern, can
                 result not only in off spilled from the vessels involved, but also in the loss of life and propertY.
                     Besid els the large spills that can occur from groundings and collisions, smaller spins Gin occur during
                 offloading and onloading operations. Section IV.B.6. discusses the historical record of spills from tankering,
                 in general. Section IV.C.1. presents assumptions and probabilities of spills from shuttle tanker activities
                 projected to occur from the proposed actions.
                     Although operational discharges from tanker transportation operations have been identified as a major
                 source of oil pollution in the past (see Section IV.B.6. for further discussion), new regulations, such as the Oil
                 Pollution Act of 1990, are expected to reduce significantly such discharges. Shuttle tankers carrying oil
                 produced as a result of the proposed actions are expected to discharge ballast and bilge waters into onshore
                 receptacle facilities.

                 c. Offshore Transport of Personnel/Supplies

                     Supplies, information, and personnel must be transported, sometimes long distances, by boats and
                 helicopters to OCS oil and gas drilling and production operations. Such activities usually beginat service/supply
                 bases located in the coastal areas. Service bases, heliports, and vessel usage of coastal areas are discussed in
                 detail in Section IV.A.3.


                 (1) Service Vessels

                     The types of vessels working for the oil and gas industry are extremely varied but can be divided according
                 to their function into three basic types: supply, crew, and utility vessels. Service vessels can also be grouped into
                 two size categories. The large category includes vessels longer than 45 m (150 ft) and are usually between 50
                 m and 60 nt (160 ft and 200 ft) in length. The small category includes mainly crew boats that average about
                 32 m (110 ft) in length. Most vessels (68%) used for OCS operations are supply boats that are in the large
                 category (Turner and Cahoon, 1987). These supply boats have a 3.5-m (12-ft) draft when loaded, and can carry
                 30 tons of materials. Crewboats draw 2-2.75 nt (7-9 ft) of water. Dry cargo supply and crewboats make up
                 about 89 percent of all vessel types (Turner and Cahoon, 1987). Utility boats perform various functions for
                 rigs and are about 100 ft long with 10- to 12-ft drafts. Examples of types of boats grouped under service vessels
                 include coring vessels, dedicated spill-response vessels, geochemical survey boats, pipe carriers,, platform supply
                 boats, and research vessels.
                     Commodities transferred from offshore and onshore are as varied as the types of vessels and include such
                 items as drilling fluids, cement, drilling equipment, food, water, and miscellaneous supplies. Each trip of a
                 service vessel averages 338 tons of materials (Turner and Cahoon, 1987).
                     The following assumptions about service vessel activity are made as part of the proposed action scenarios:
                 (a) crewboats will have 6 personnel per boat; supply boats will have 20 personnel; (b) service vessels win travel
                 to exploratory and development well drilling sites three times per week; (c) service vessels will travel to
                 production sites much less, making one trip per five production platform complexes each week; (d) one trip
                 represents a round trip, that is, the vessel travels from the service base to the offshore site(s), then returns to
                 the service base; (e) once reaching navigation channels, a vessel takes, on an average, 4 hours to reach the
                 shorebase; and (f) in the WPA, most service vessels will be traveling about 175 mi round trip, taking 15 hours
                 to complete their offshore journey; in the CPA, most service vessels are expected to travel around 260 mi
                 (round trip) offshore, traveling 23 hours. Perhaps most importantly, it is assumed that some new service vessels
                 will have to be built that are larger than those currently used. Larger, deeper-draft vessels rnay be needed to
                 reach oil and gas operations projected to occur far from shore in deeper water.
                     Central PlanningArea: Table IV-2 provides the number of service vessel trips projected to occur as part
                 of the Base Case and High Case scenarios for proposed Sale 142. Under the Base Case, 17,600 service vessel
                 trips are expected during the 35-year life of the proposed actions. Under the High Case, there will be 30,800












                                                                                                                            IV-23


              trips during the 35-year life of the proposed action. About 70 percent of these trips will originate from offshore
              Subareas C-3 and C-4.
                  Westem PlanningArea: Table IV-3 provides the number of service vessel trips projected to occur as part
              of the Base Case and High Case scenarios for proposed Sale 143. Under the Base Case, 8,300 service vessel
              trips are expected during the 35-year life of the proposed action. Under the High Case, there will be 14,500
              trips during the 35-year fife of the proposed action. Most of these trips will originate from offshore Subarea
              W-3.
                  The type and size of vessel and the vessel speed and route must be considered when evaluating potential
              impacts. Service vessel use on the OCS can cause air and water quality degradation, alteration of the natural
              habitat by vessel movement and anchoring operations, and collisions with marine mammals or sea turtles. Not
              analyzed in this document, collisions resulting in property damage, fire, and loss of life also can occur from the
              larger service vessels. Deck drainage, bilge pumping, and accidental loss of trash and debris can affect water
              quality and associated biota (Sections IV.A.2.d.(5)(f), Trash and Debris and IV.A-3.c.(3)(b), Operational
              Discharges). Navigation channels built to support service-vessel traffic change current and circulation patterns
              and allow saltwater intrusion into wetland areas. Frequent vessel traffic leads to accelerated erosion along
              navigation channels in the coastal area and to increased turbidity and other secondary impacts. Impacts due
              to navigation channels are discussed in Section IV.A.3.c.(3). This section also discusses the deepening of the
              channels that will be required to accommodate any new, deep-draft service vessels.

              (2) Helicopters

                  Helicopters are the primary mode of transporting personnel between shore and offshore platforms.
              Helicopter noise can have adverse impacts on birds, marine mammals, and recreational beach users if flight
              ceilings are lower than recommended levels. The Federal Aviation Administration (FAA) recommends
              operational safety procedures and a flight ceiling of 1,000 ft over land, except National Wildlife Refuges and
              National Park Lands, where at least a 2,000-ft ceiling is recommended. The MMS sent a special letter to all
              Gulf of Mexico lessees in 1990 informing and reminding them of the special flight ceiling protection
              recommended for flights over National Wildlife Refuges and National Parks. The Offshore Operator's
              Committee also provided helicopter companies with updated information on the location of national parks,
              refuges and seashores in the coastal areas of the Gulf region (Helicopter Safety Advisory Conference, 1991).
                  Helicopters transporting offshore personnel typically maintain at least a 1,000-ft elevation over water,
              except when visibility is limited or for short trips between platforms. The analysis of environmental impacts
              in this document assumes that pilots adhere to the FAA recommendations of flight ceilings of 1,000 ft or higher
              and to establish safety procedures.
                  It is assumed for analysis purposes that helicopters will visit drilling rigs, structures during development
              drilling, each production platform complex between one and two times per day, and pipeline lay barges one
              time per day. Based on these assumptions, 368,000 and 619,000 helicopter trips are projected in the CPA
              under the Base Case and High Case scenarios, respectively-, and 131,000 and 375,000 trips in the WPA are
              projected to occur (Tables IV-2 and IV-3). A trip is defined as a take-off and landing at an offshore facility.
                  Historically, helicopters have completed 13-14 flights, averaging 15 minutes per flight, in a typical day; they
              return to shore-based heliports after going to an average of 3-4 offshore facilities. Therefore, they make 7-8
              coastline crossings per day, which computes to about two crossings per 3-4 flights (a flight is equivalent to one
              takeoff and landing). Flights in the future are assumed to take 30 minutes to account for the fact that activity
              will take place farther offshore.

              d. Offshore Impacting Factors Related to the Proposed Actions

              (1) Bottom Disturbances

                  Disruption of the seafloor by the placement of structures (including rigs, platforms, and pipelines) and
              anchors will occur from oil and gas operations. The magnitude of these disruptions on associated resources,












                   IV-24

                   particularly biological and archaeological resources, is dependent on a number of factors, including the
                   configuration of the exploratory drilling rigs, production platforms, and pipelines that are being installed, the
                   type of oil and gas operation, and the depth and currents of the waters. The installation of structures across
                   parts of the OCS that include potential archaeological sites and unique and sensitive benthic biological
                   communities, such as coral reefs and hard-bottom pinnacle and chemosynthetic communifies, could result in
                   mechanical damage from dredging and anchoring activities. Various Notices to Lessees (NTUs) exist, and
                   stipulations are proposed to protect archaeological and sensitive biological resources from damage during these
                   activities. The placement of offshore structures could also affect water quality and fishery resources.

                   (a) Fixed Structures

                   Bottom Area Contacted

                       Each platform placed on the OCS disturbs some of the bottom directly beneath !I - stracture and around
                   it where anchors are set to hold the vessel or structure in place. Some generalities may be made to determine
                   the "average" bottom area contacted by installation of such structures. For purposes of analysis, this EIS
                   assumes the following. The mud mats, which are used to support the jack-up rigs (most -commonly used in
                   water depths less than 30.5 m (100 ft)) are approximately 0.4 ha (0.9 ac) in area. A three-leg rig will thus
                   directly impinge on an area approximately 1.1 ha (2.7 ac). In most cases, anchor impacts also are associated
                   with these direct impacts. An additional 0.4 ha (1.0 ac) has been estimated for these impacts., bringing the total
                   area impacted by a typical rig to 1.5 ha (3.7 ac). Semi-submersible rigs, used in water depths from about 21
                   m (70 ft) to about 457 m (1,500 ft), disturb roughly the same 1.5 ha of bottom. It is assumed that 2 ha (4.9
                   ac) of the bottom will be directly affected by the installation of production platforms; in water depths greater
                   than 457 m, where tension-leg platforms are projected to be used, the area affected doubles to 4 ha (9.9 ac).
                   Pipelines disturb 0.32 ha (0.8 ac) for each kilometer (0.62 mi) of pipeline installed.
                       The development scenario for the Base Case for proposed Sale 142 assumes 341) exploration and
                   delineation wells and 30 platform complexes (Table IV-2). This equals the direct disturbance of approximately
                   192 ha (474 ac) of open ocean bottom. Two hundred forty kilometers (149 mi) of pipe gathering lines are
                   estimated to be installed, resulting in the disturbance of another 77 ha (190 ac) of bottom.,
                       The development scenario for the Base Case for proposed Sale 143 assumes 210 exploration and
                   delineation wells and 10 platforms (Table IV-3). This equals the direct disturbance of approximately 93 ha
                   (230 ac) of open ocean bottom. Eighty kilometers (50 mi) of pipelines are estimated to be installed, resulting
                   in the disturbance of another 26 ha (64 ac) of bottom.

                   Volume of Sediment Displaced

                       The trenching (burying) of pipelines, which is required only in water depths less than 61 m (200 ft),
                   resuspends some 5,000 M3 (6,540 yd3) of sediments per kilometer (0.62 mi). For proposed Sale 142, this results
                   in about 320,000 M3 (418,560 yd3) of sediments being resuspended into the water column over the 35 years of
                   activity that would result.' For proposed Sale 143, about 40,000 M3 (52,320 yd   3) would be resuspended.
                       The effects of sediment resuspension include increased water turbidities and mobilization of pollutants in
                   the water column.

                   (b) Anchoring

                       Each drill ship, exploration rig, platform, and pipeline placed on the OCS disturbs, in addition to some of
                   the bottom directly impacted by the structure, some area or areas around it where anchors are set to hold the
                   vessel, structure, or support vessel in place. In addition, pipelaying barges use an array of eight 9,000-kg
                   (20,000-1b) anchors to both position the barge and to move it forward along the pipeline route. These anchors
                   are continuously moved as the pipe-laying operation proceeds. The area actually affected by anchors will
                   depend on water depth, wind, currents, chain length, and the size of the anchor and chain. Anchor damage












                                                                                                                          IV-25


              includes the crushing and breaking of coral heads. Also, anchoring often destroys a wide swath of sessile
              organisms when the anchor is dragged or when the vessel swings at the anchor, causing the anchor chain to
              drag the seafloor.
                  Service vessel anchoring is assumed to not occur in water depths greater than 152 in (500 ft) and only
              occasionally in shallower waters. Barges and shuttle tankers are assumed to always tie up to a production
              system rather than anchor. Mooring buoys may be placed near drilling rigs or platforms so that service vessels
              need not anchor, especially in deeper water (in all depths of water, vessels may also tie up directly to the rig
              or platform). These temporarily installed anchors will most likely be smaller and lighter than those described
              above and, thus, will be less damaging to the bottom. Moreover, installing one buoy will preclude the need
              for numerous individual vessel anchoring incidents.
                  With the proposed Live Bottom and Topographic Features Stipulations (Sections II.A-1.c. and II.B.l.c.),
              anchoring impacts from the offshore industry would be largely prevented.

              (2) BoUom Debris

                  Bottom debris is herein defined as ferromagnetic and non-ferromagnetic material resting on the seabed
              (such as cable, tools, pipe, drums, structural parts of platforms, as well as objects made of plastic, aluminum,
              wood, etc.). This material is accidentally lost, or illegally tossed, by workers from fixed structures, jack-up
              barges, drilling ships, and during pipeline emplacement. Varying quantities of ferromagnetic bottom debris may
              be lost, or illegally tossed, per operation. The maximum quantity of bottom debris per operation is assumed
              to be several tons. A total of 840 exploration and delineation and development wells are expected to be drilled
              in the CPA under the Base Case. In addition, 30 platform installations are expected and 240 km of pipelines
              are projected for the CPA (Table IV-2). It is assumed, therefore, that up to several thousand tons of bottom
              debris associated with OCS activity may result from the proposed action. Underwater OCS ferromagnetic
              debris may result in the masking of magnetic signatures from historic period shipwrecks. Bottom debris may
              also result in the damage or loss of commercial fishing equipment, gear (primarily nets), and/or fisheries catch.
              Extensive analysis of remote-sensing surveys within developed blocks indicates that the majority of
              ferromagnetic bottom debris associated with OCS exploration and development activities falls within 1,500 ft
              of the structure/jack-up/lay barge.
                  Underwater OCS debris can become snagged by fishery gear resulting in trawl and vessel damage, business
              downtime, and loss of catch. Approximately 97 structures were removed from the Gulf of Mexico in 1990
              (Shaw, personal comm., 1991). Recently, in light of projected increases in the number of annual structure
              removals, the Louisiana Concerned Shrimpers Association brought to the attention of MMS its concern over
              debris remaining on the bottom at the site after structures are removed. Subpart C of 30 CFR 250.112(i)
              requires that the locations of structure removal be cleared of all bottom obstructions. To examine this conflict
              more closely, MMS established a Regional Site Clearance Committee in 1989. The Committee's membership
              consists of representatives from the State of Louisiana's Department of Wildlife and Fisheries, the Louisiana
              Concerned Shrimpers Association, the Offshore Operators Committee, and the MMS Offices of Field
              Operations, Leasing and Environment, and the Regional Director. The Committee drafted and distributed
              through MMS an NTL (90-03) to all offshore operators that is a minimum interim requirement for site
              clearance (and verification) of abandoned oil and gas structures in the Gulf. After additional information is
              collected from operational experience under NTL 90-03, new regulations will be drafted. It is assumed that
              offshore operators will adhere to the NTL 90-03 guidelines and eliminate bottom debris associated with
              platforms removed as a result of the proposed action. It is assumed that the economic loss to Gulf fishermen
              from bottom debris/gear conflict as a result of the proposed action will be less than one percent of the value
              of any fiscal year's commercial fisheries landings for the entire life of the proposed action.
                  Most financial losses to Gulf fishermen from bottom debris and fishing gear conflicts are covered by claims
              made to the Fishermen's Contingency Fund (FCF) administered by the Financial Services Division of NMFS
              (Jackson, written comm., 1991). (See Section I.B.3.d.(3)(f) for a detailed discussion of the FCF.) During FY
              91, 124 claims of conflict between fishermen and offshore oil and gas bottom debris were processed with 43
              percent being approved for a total of $213,777 awarded to the fishermen. It is assumed that any economic loss











                  IV-26


                  to Gulf fishermen from bottom debris/gear conflicts as a result of the proposed action will be less than one
                  percent of value of that same year's commercial fisheries landings for the entire life of the 1?roposed action.

                  (3) Space-Use Conflicts

                      The presence of a production platform, with a surrounding 100-m navigational safety zone, results in the
                  loss of approximatQy 6 ha (15 ac) of trawling area to commercial fishermen and causes space-use conflicts in
                  water depths of less than 152 in (USDOI, MMS, 1991a). Exploratory drilling rigs spend approximately 45 days
                  per well on site and are a short-lived interference to commercial fishing. Virtually all commercial trawl fishing
                  in the Gulf is performed in water depths less than 152 m, and those platforms constructedin greater depths
                  will not conflict with commercial fishing. Seismic surveys are not an issue of space-use conf[ict in the Gulf of
                  Mexico commercial fisheries. The development scenarios in the CPA for the Base and High Cases for
                  proposed Sale 142 assume that, on average, approximately 73 ha (180 ac) and 82 ha (202 ac), respectively, win
                  be lost to commercial fishing per year during the 33 years that production platforms are in p1ace (Table IV-2).
                  The development scenarios in the WPA for the Base and High Cases for proposed Sale 143 assume that
                  approximately 9 ha (21 ac) (Table IV-3) will be lost to commercial fishing in each Case. During the peak year
                  (Base Case) for the CPA, 120 ha (296 ac) may be unavailable to fishing and for the WPA, 15 ha (37 ac).

                  (4) Aesthetic Interference

                      Drilling rigs and platforms can directly impact public perceptions of coastal and nearshore seascape views.
                  Indirectly, rigs and platforms are associated with oil spills and marine trash and debris, which can also adversely
                  affect the aesthetics of the marine environment or coastal shorefront. Platforms and drilling rigs established
                  in the first two or three tiers of nearshore Federal oil and gas lease tracts (3-10 mi from shore) can be readily
                  seen and recognized during good weather conditions from the southern most coastal shorelines of Louisiana,
                  Mississippi, and Alabama. Drilling rigs and very large production platforms 10 or more miles from shore, such
                  as those operating in the first tier of Federal oil and gas lease tracts off Texas, may be barely perceptible from
                  shore in the fairest of weather conditions, but would be indistinguishable from objects such as ships, and are
                  unlikely to spoil natural shorefront vistas. On a clear night, lights from the top of drilling rigs could be visible
                  almost to where they dip below the horizon from the curvature of the earth (about 20 mi). Long-term oil and
                  gas production in State waters off 'Louisiana and Texas, and recent State water production and exploratory
                  drilling within view of the shorelines of Mississippi and Alabama have accustomed many coastal residents to
                  the visual presence of drilling rigs -and production platforms in nearshore coastal waters.
                      For purposes of this EIS, it is expected that 16 platform complexes will be installed in offshore Subareas
                  C-1 and C-3 (Table IV-2). Under the High Case scenario, as many as 24 platform complexes would be
                  installed in coastal Subareas C-1 and C-3. Based on MMS in-house analysis, it is more likely that most of the
                  platforms installed in these subareas will be beyond 10 mi (16 km) from shore. It is assumed, however, that
                  at least one drilling rig will operate in coastal nearshore tracts and that one production platform will be
                  installed within the first two or three tiers of Federal lease blocks off the coast of Louisiana, Mississippi, or
                  Alabama. All rigs and platforms located on the OCS as a result of proposed Sale 143 (offshore Texas) will
                  be operating 10 or more miles from the coastal shoreline.

                  (5) Offshore Operational Wastes

                      The largest quantities of operational wastes generated by offshore oil and gas exploration and production
                  activities include produced water, drilling fluids and cuttings, ballast water, and storage displacement water.
                  Other major wastes from the offshore oil and gas industry include the following: from drilling- -waste chemicals,
                  fracturing and acidifying fluids, and well completion and workover fluids; from production--producedsand, deck
                  drainage, and miscellaneous well fluids (cement, BOP fluid); and from other sources--sanitary and domestic
                  wastes, gas and oil processing wastes, and miscellaneous minor discharges. In general, oily wastes such as
                  produced waters and sands, as well as processing fluids, are collected into one drainage system and then sent












                                                                                                                         IV-27


              into a sump tank where oil is separated, often by gravity. The water phase is then discharged overboard either
              at the surface or it is shunted. The offy sludge and sometimes the offy wastes themselves, such as produced
              sands, are brought onshore for disposal. Other disposal alternatives, such as downhole injection, encapsulation,
              or offshore storage, require prior approval by the Regional Director. For analytical purposes, this document
              assumes that USEPA's effluent limitation guideline regulations (Section 1.13.3.d.(3)(e)), will be promulgated.
              In the development of estimates of future discharges, characteristics of the waste streams, and disposal
              methods, MMS assumes that the proposed effluent limitations are finalized and that USEPA's preferred option
              for each waste, as identified in the proposed rule (40 CFR 435), will be chosen.
                   Major contaminants or chemical properties of concern in oil and gas operational wastes can include high
              salinity, sulfides, low pH, high biological and chemical oxygen demand, various metals, crude oil compounds,
              organic acids, and radionuclides. Most recently, the public has expressed considerable confusion and concern
              regarding radionuclide contamination in oil-field wastes generated in the Gulf of Mexico. Over the past several
              years, measurements of elevated levels of radiation in used oil-field equipment have raised the sensitivity of
              the public and regulators to the fact that naturally occurring radioactive materials are generated from the
              mineral-extraction process.
                   It is now known that naturally occurring radioactive materials, collectively known by the acronym NORM,
              can occur in significantly higher than background levels in many oil-field wastes. As the production stream is
              brought to the surface, NORM may remain dissolved at diluted levels or may precipitate as scale on the insides
              of well tubing, pipes, and processing equipment and in the sludges that collect in the tanks, vessels, and
              filtration units. Offshore, NORM is found in oil and gas production equipment and in the produced sands,
              solids, and waters generated during production. Drilling muds and cuttings and workover fluids have also been
              found to be contaminated with NORM. Sections that follow provide information about levels of NORM
              measured in each waste type. Onshore, solid NORM may be found in gas processing plant equipment, in
              heater treaters and separators at separation facilities, and associated with pipeyards.
                   The NORM is defined as any naturally occurring material that emits low levels of radioactivity, originating
              from processes not associated with recovery of radioactive material. All soils and rocks contain some
              radioactive materials (unstable elements), and any activity that concentrates them to levels well above their
              natural abundance--such as mineral extraction and refining--may potentially create a health hazard. The
              radionuclides of concern in NORM are Radium-226, Radium-228, and other isotopes in the radioactive decay
              chains of uranium and thorium. Radium is a long-lived nuclide with a 1600-year half-life and when ingested,
              concentrates in the bones. Radium emits alpha, beta, and gamma radiation. Alpha particles are the most
              energetic radiation but are easily blocked and cannot penetrate the skin. However, if ingested, alpha radiation
              can cause bone cancer, or if airborne and breathed, it can cause lung cancer. Radium also emits gamma rays,
              which are very penetrating and considered hazardous at high concentrations.
                   Because NORM materials have relatively low activity levels compared to nuclear industry man-made
              isotopes and because of their natural presence, they have been largely ignored until now by regulators. The
              NORM were not covered by the Atomic Energy Act of 1954 and, thus, are not regulated by the Nuclear
              Regulatory Authority nor USEPA as radioactive wastes. At present, there are no Federal regulations for
              handling and disposing of NORM-contaminated materials. The Louisiana Department of Environmental
              Quality (DEQ) is the only State agency to have adopted NORM regulations (Chapter 14, "Regulation and
              Licensing of Naturally Occurring Radioactive Materials (NORM), LAC 33:XV). On September 20,1989, the
              DEQ developed regulations that provide strict disposal requirements for all NORM materials emitting radiation
              greater than 50 microroentgens (micro-REMS) per hour and that establish guidelines for conducting NORM
              confirmatory surveys of suspected contaminated land. The State of Texas has, at present, draft proposed
              regulations (Draft 2 Texas Regulations for Control of Radiation, Part 46, "Licensing of NORM").
                   Part of the lack of regulation stems from the fact that, at present, little can be concluded definitely
              concerning the effects of this wastes and associated disposal practices on both human health or marine life.
              While scientists know that radiation causes cancer, there is deep disagreement over just how much radiation
              it takes to affect human health. Even less is understood about the fate of NORM from the overboard disposal
              of oil-field wastes, about how much marine uptake occurs, and what this uptake means to the health of the
              marine ecosystem. Selection for the oil industry of criteria for contaminant levels and exposure rates based











                IV-28


                on radiation limits set for other industries is premature until more is known about the fate and effects of
                oil-field NORM.
                    Despite the lack of conclusive data on the effects of NORM, the Minerals Management Service initiated
                a policy to control the overboard disposal of OCS-generated NORM solid wastes under the authority of the
                OCS Lands Act. By MMS regulatory authority to approve the disposal of oil-field waste (30 CFR 250.40), the
                agency has taken a major step and has developed interim guidelines to industry for the overboard disposal and
                handling of NORM-contaminated production and workover solids. Also, USEPA is now considering
                establishing discharge limits on the radionuclide content of produced water as part of the effluent limitation
                guideline regulations.
                    An interim policy Letter to Lessees (LTL) was issued on November 20, 1990, requiring 2ill disposal to be
                approved by the MMS Regional Office (Appendix E). The granting of approval for the overboard disposal
                of solids was basically put on hold after this LTL was issued. Industry applications received by MMS showed
                that the majority of the accumulations were solids having radiation human exposure limits equal to or very near
                background measurements. Since MMS was not approving overboard offshore disposal, the operators have
                been either storing the materials offshore or transporting the material onshore for disposal at approved sites.
                Specific problems related to onshore disposal of NORM-contaminated production solids is discussed in Section
                IV.A.3.c.(4)(b). Given the radiation exposure levels being reported and the problems associated with the
                onshore disposal of these wastes, MMS has decided that overboard disposal of most solids represents the best
                disposal alternative at this time. A second LTL, issued December 11, 1991, establishes more detailed interim
                guidelines for the reporting and disposal of produced well solids and for collecting data to be used to
                promulgate formal policy. (Appendix E contains both LTL's). In general, the second LTL allows MMS to
                approve all overboard disposal of production solids with a radiation dose rate equivalent of no greater than
                25 microroentgens per hour above background. Material with higher measurements will be considered on a
                case-by-case basis. This level is based on proposed worker and public health exposure limits in the
                aforementioned proposed Texas and Louisiana regulations. No concentration limits for radium per unit
                discharge, i.e., picoCuries/gram, will be determined until more is understood about the physical and chemical
                properties of oil-field NORM, although industry is asked to analyze the samples for total radium concentrations.
                   @ There is a tremendous effort underway by MMS, the Department of Energy, USEPA, State agencies, and
                industry to gather data on NORM contamination levels; on the fate of discharges and the environmental
                consequencesof current disposal practices of NORM-contaminated oil-field wastes; and on disposal alternatives
                and treatment methods. Industry is leading the way in studies that are determining expected levels and the
                fate and effects of offshore, disposal of these wastes. The American Petroleum Institute (API), the Offshore
                Operators Committee's (OOC) Environmental Science Task Force, and individual oil companies are gathering
                much needed data. The MMS is working cooperatively with these agencies and industry to study, as quickly
                as possible, all information that is being generated. Few conclusions can be made at this time.
                    Human health effects have received the most attention. Brookhaven National Laboratories (1991), as part
                of an API study, concluded that areas near coastal produced-water discharges did not exhibit NORM
                contamination above USEPA!s reportable quantity for worker risk. Brookhaven did postulate that such
                discharges could pose a small risk to human health through ingestion of contaminated fish and oysters. The
                USEPA, in its draft risk assessment, suggests that diffuse NORM presents little hazard to most people, with
                the exception of workers who inhale radium dust during improper disposal activities. In 1993, MMS will begin
                a study that will evaluate data on human exposure from various disposal alternatives.
                    To understand ecosystem impacts, the fate of offshore discharges is being assessed through a number of
                studies. Industry has recently completed a study of the dispersion of produced well solids discharged directly
                from a production platform. The study focused on the ability of current technology to clean or wash produced
                solids and to measure the environmental fate in the surrounding area. One hundred and forty-four barrels of
                produced sand, containing from 19-68 picocuries per gram of radium-226, was discharged. Sediments around
                the discharge site showed radioactivity levels indistinguishable from background radioactivity (Randolph et al.,
                in press). Offshore sand discharge was also modeled using OOC's dispersion plume model. The results showed
                a 5 pCi/g maximum elevation of surrounding bottom sediments. The study also examined water and sediment
                NORM contamination at 12 OCS discharge sites where solids were discharged in the past year (Randolph et
                al., in press).












                                                                                                                           IV-29


                 Although data is available that shows biological uptake of NORM by oysters and fish in inland coastal
            waters (Rabalais et al., 1990; St. P6, 1990; Mulino and Rayle, 1992) near produced-water outfalls (now
            terminated), no studies have yet been completed examining fish and oysters near platforms for NORM
            contamination. Avand Corporation is examining the effect of NORM discharged on caged organisms at six
            OCS platforms in a study funded by USEPA. The draft NPDES general permit for the Western Gulf of
            Mexico (Section I.B.3.d.(3)(e)) is proposing the monitoring of water and fish tissue for radium levels near
            produced-water offshore outfalls. A Department of Energy study, which is underway, will monitor the recovery
            of impacted wetland and open bay, produced-water discharge sites in coastal Louisiana and Texas.
                 In conclusion, it is believed that it is premature to assume that there will be or are significant effects
            occurring from the offshore disposal of NORM-contaminated liquids and solids. At present, MMS assumes
            that the ongoing efforts to study information regarding the fate and effects of NORM-contaminated wastes will
            result in the proper management of all future disposal of NORM wastes, preventing any significant
            environmental damage.

            (a) Drilling Muds and Cunings

                 The major source of contamination from drilling operations is the drilling fluids, or "muds," and the cuttings
            from the drill bit. Drilling fluids are suspensions of solids and dissolved materials in a base of water or oil that
            are used in rotary drilling for oil and gas exploration and development to remove cuttings from beneath the
            bit, to control well pressure, to cool and lubricate the drill string, and to seal the well.
                 Drilling fluids/muds are composed of bulk constituents and special-purpose additives. Although water-
            based systems are the most common muds used, oil-based fluids are used for a variety of applications, such
            as high temperature wells, deep holes, and wells where sticking and hole stabilization is a problem. In addition,
            water-based drilling fluids may have diesel oil or mineral oil added to them. Hydrocarbons (diesel or mineral
            oil) were added for lubricity in 12 percent of the wells surveyed in 1984 by API (USEPA, 1991). Drilling fluids
            also may contain entrained formation hydrocarbons. The principle contaminants of concern in drilling muds
            include oil content, biochemical oxygen demand, chemical oxygen demand, total organic carbon, and priority
            pollutants (excluding pesticides). Stephenson (1991) has recently analyzed a limited data set of muds from 14
            offshore wells for radium-226 and -228 content (naturally occurring radioactive material, or NORM). The
            analysis showed that NORM concentrations in the mud averaged four picoCuries and were at or below the
            average NORM concentrations in surface sediments in uncontaminated areas. The primary concern in the drill
            cuttings waste stream is the discharge of oil and other mud constituents that adhere to or are mixed with waste
            cuttings.
                 The circulated mud brings to the surface silts, cuttings, water, oil and gas, which must be separated out.
            The mud is often recycled, especially on a multiple-well platform. However, drilling fluids must be eventually
            disposed of for a number of reasons, as must drill cuttings from the drilled formation. Although drilling
            discharges can be barged ashore or to other sites at sea for disposal, cost and operational considerations favor
            on-site disposal by either overboard discharge or shunting through a pipe to some depth. The cuttings., silt,
            and sand are discharged overboard if they do not contain free oil. The heavier particles sink to the bottom
            while the mud and fines are swept downcurrent away from the platform. Based on observations of discharges,
            the plumes are spread out at some depth, depending on density characteristics, and are rapidly dispersed by
            the turbulent diffusion characteristics of the ocean. Horizontal turbulent diffusion results in dilution of the
            plumes by a factor of 10,000 or more within an hour of release and an even greater dilution of suspended
            components because of settling (Brandsma and Sauer, 1983). At most depths typical of the continental shelf,
            the majority of discharged fluids and cuttings are initially deposited on the seabed within 1,000 in of the
            discharge point. This material may persist as initially deposited or may undergo bioturbation and rapid or
            prolonged dispersion, depending on the energy of the bottom-boundary layer. Effects on benthos have been
            observed in the field under low to moderate energy regimes within 1,000 in of the discharge point.
                 As discussed above, MMS assumes that the USEPA proposed effluent limitations will be finalized. These
            effluent limitations for drilling fluids and cuttings are (1) prohibit any discharge within 4 mi from shoreline, (2)
            limit the acute toxicity to a minimum 96-hour LC50 of 30,000 ppm as measured in the diluted suspended












                   IV-30

                   particulate phase, (3) prohibit the discharge of diesel off, (4) prohibit the discharge of free oil, and (5) limit
                   of the discharge of cadmium and mercury in whole drilling mud at the point of discharge to 1 mg/kg.
                       For analysis purposes (Section IV.D.), it is assumed that there will be 7,134 bbl of drilling fluids and 1,853
                   bbl of cuttings produced per exploratory well, and 6,749 bbl of drilling fluids and 1,430 bbl of cuttings produced
                   per development well (USEPA, 1991). The different volumes are based on the expected different average
                   depth for the two types of wells. It is assumed that oil-based muds will be used when drilling operations exceed
                   10,000 ft in depth. Given this and the proposed effluent limitation of no discharge closer than 4 mi from
                   shoreline, it is assumed that 18.1 percent of drilling muds will be brought onshore for disposal (USEPA, 1991).
                       Assumptions regarding the fate of discharged muds and cuttings include the following: horizontal turbulent
                   diffusion results in the dilution of these discharges by a factor of 10,000 within one hour of discharge and the
                   plume diminishes to background levels in the water column within 1,000 m of the discharge point.

                   (b) P@oduced Waters

                       Produced water (also known as production water or produced brine) is the total water discharged from
                   the oil and gas extraction process. It is comprised of the formation waters, injection water (if used for
                   secondary oil recovery and broken through into the off formation), and various chemicals added during the oil
                   and water separation process. During production of oil and gas, formation water (also called fossil or connate
                   water) located in the permeable sedimentary rock strata may be brought up to the surface. This water
                   comprises the bulk of produced water. The amount of produced water generated per volume of oil varies
                   greatly, but it is the largest, single volume waste stream in the entire exploration and production process. Most
                   older wells, as oil and gas production declines, produce increasing amounts of water. In some oil-fields, water
                   emerges with the oil in the early stages of development; whereas in other wells, appreciablewater never comes
                   up with the off. Produced water can constitute from 2 to 98 percent of the waste stream of a producing field.
                       Produced waters are usually high in total dissolved solids (salinity), total organic carbon, and low in
                   dissolved oxygen. Other basic components include heavy metals, elemental sulfur and sulfide, organic acids,
                   treating chemicals, and emulsified and particulate crude oil constituents. Salinity can vary from a few parts per
                   thousand (ppt) to 300 ppt (the salinity of saltwater is 35 ppt). Metals that may be present in produced waters
                   in higher concentrations than seawater include aluminum, barium, beryllium, cadmium, chromium, copper, iron,
                   lead, manganese, mercury, nickel, silver, vanadium, and zinc. Because these waters are closely intermingled
                   with p.:,troleum, they contain variable concentrations of dissolved and dispersed petroleum hydrocarbons. Oil
                   and grease content recently measured in produced-water discharges from 30 platforms in the Gulf of Mexico
                   averaged (flow weighted) 89.8 ppm (USEPA, 1991). In addition, high concentrations of other soluble organic
                   compounds (characteristically greater than 200 ppm) are found, particularly phenols and organic acids (Boesch,
                   1988). Treating chemicals are added deliberately by the offshore operator to treat or prevent operational
                   problems that may occur in the production process (Stephenson, 1991). Treating chemicals can generally be
                   classified into three categories: production treating chemicals, gas processing chemicals, and stimulation and
                   workover chemicals. These chemicals are discussed in more depth in Section IV.A.2.d.(5)(c).
                       Concentrations of NORM greater than background levels are found to exist in off-field produced waters.
                   The NORM measured in produced-water samples from Gulf oil platforms (both State and OCS production)
                   exhibit radium activities as high as 2,801 picoCuries; per liter (pCi/1) (Snavely, 1989; Rabalais et al., 1991;
                   Stephenson and Supernaw, 1990; Louisiana Dept. of Environmental Quality, 1990). Snavely found that 78
                   percent of the wells sampled in a number of studies he reviewed exceeded 50 pCi/l. Most recently, the
                   Offshore Operators Committee analyzed 42 platforms on the Gulf of Mexico OCS to determine radionuclide
                   content The mean concentration of soluble Ra-226 was 262 pCi/l with a range of 4.1-584 pCi/l (Stephenson
                   and Supernaw, 1990). On February 20, 1990, the Louisiana Dept. of Environmental Quality issued an
                   Emergency Rule requiring a single analysis for Ra-226 and Ra-228 in each State-regulated, produced-water
                   outfall; 153 samples were taken and the radium measured. The mean concentration was UO pCi/I for Ra-226
                   and 181 pCi/I for Ra-228, with a high of 930 pCi/I for Ra-226. The USEPA reports that average open-ocean
                   surface waters contain about 0.05 pCi/l, whereas coastal waters do not generally contain kvels higher than 1
                   pCi/l.












                                                                                                                            IV-31


                    Produced water may be reinjected into the formation or treated to decrease its oil content and then
                discharged into surface waters. An examination of production facilities discharging produced waters showed
                that only about 20 percent of existing structures discharged produced waters directly into surrounding waters;
                the other facilities thereby transporting their produced waters to these sites (1989 in-house analysis). Although
                much of the water produced from OCS oil and gas operations is discharged offshore, some of the water is
                piped ashore and then treated and disposed of at coastal separation facilities. (Section IV.A_3.c.(4)(a) discusses
                onshore disposal of produced waters.) About 11 percent of produced waters generated offshore are expected
                to be shipped into Louisiana State waters for disposal.
                    Projections of the amount of produced water generated from operations associated with the proposed
                actions are derived from an analysis described in the supporting reports for the proposed USEPA (1991)
                effluent limitations. For a typical well, about 450 bbI of produced water per oil well per day and about 68 bbI
                of water per gas well per day can be expected. Given this, total estimates of produced waters generated over
                the 20-year platform life are 317,942,000 bbl in the CPA and 126,203,000 bbI in the WPA (Tables IV-2 and
                IV-3). Subtracting the 11 percent of produced waters expected to be brought onshore for disposal, the amount
                of produced waters projected to be discharged into CPA offshore waters is about 283 MMbbl.
                    A number of studies have investigated the fate and effects of OCS discharges around production platforms
                in open waters (USDOI, MMS, 1990b). These studies and their conclusions are discussed in Section
                IV.B.Lb.(4)(e).

                (c) Other DevelopmentlProduction Fluids

                    Other discharges associated with OCS activities include well treatment, completion, and workover fluids;
                deck drainage; and minor discharges.
                    Well treatment, completion, and workover fluids are proposed for regulation under the U.S. Environmental
                Protection Agency's NPDES permit. Well treatment fluids are any fluids used to restore or improve
                productivity of the formation. Well completion fluids are used to prepare the well for actual oil extraction.
                Workover fluids are used to restore an abandoned well to production or to repair a well. Composition of these
                fluids varies, but they usually are low solids, weighted brines with specialty additives, or acidic solutions.
                Principle contaminants can include low pH, oil and grease, metals, a variety of organic compounds, and
                NORM. Because these fluids are sometimes used to dissolve NORM-contaminated scale buildups, their waste
                streams have been found to have radioactive isotope concentrations as high as 25,000 pCi/l.
                    These fluids may remain in the formation, become spent (if acidic), resurface with the produced fluid as
                a discrete slug, or mingle with drilling fluids or produced water and become part of these waste streams. If
                they appear as a discrete slug upon resurfacing, they can be disposed of, stored, reused, or treated and
                discharged. One Gulf operator reported well treatment fluids usage at a rate of 1,283 bbl per discharge, with
                one discharge per workover activity (USEPA, 1991). However, it was not possible to develop estimates of
                volumes that may be discharged from production associated with the proposed actions.
                    The USEPA is considering three effluent limitation options for these fluids: (1) no discharge of free oil;
                (2) zero discharge of any concentrated slug of fluids along with a 100-bbl buffer on either side of the slug; or
                (3) no discharge. When the fluids are mingled with produced waters, they would have to meet the same
                requirements as proposed for produced water discharges.
                    Deck drainage results from rain runoff, miscellaneous leakage and spills, and washdown of the platforms
                or drilling rigs. Deck drainage is usually contaminated with oil and grease and a number of hazardous
                chemicals and trace metals in low concentrations. Measurements of influent oil and grease content range from
                1-16,908 ppm; and oil and grease in the discharged drainage range from 1-673 ppm, showing that oil and grease
                can greatly exceed the discharge limits of produced waters (USEPA, 1991). The source of the oil in the deck
                drainage is any residual oil from previous spills and leakage of oils and other production chemicals used by the
                facility. Oil may also be present due to the washdown solvents. Platforms have pans and sumps that collect
                such drainage. The drainage is gravity separated into wastes materials and effluent. The effluent can be
                treated separated or combined with produced water, and discharged overboard. The waste materials are











                 IV-32


                 treated, used in the drilling mud system, or transported to shore for disposal. The USEPA proposed effluent
                 limitation for deck drainage are (1) no free oil and (2) same limitations selected for produced waters.
                          ns
                      The quantities of deck drainage can vary greatly. An analyis of 950 Gulf of Mexico platforms during 1982-
                 1983 measured deck drainage quantities ranging from 1 to 4,304 bbl/day with a average of 50 bbl/day (USEPA,
                 1991). No estimates of quantities of deck drainage discharges are provided for the proposed actions.
                      The term "minor discharges" is defined by USEPA (1991) to include all other point sourcA-. discharges other
                 than produced water, drilling fluids, deck drainage, well treatment and workover fluids, and sanitary and
                 domestic wastes. These wastes are assumed to be minor, and no regulatory control exists or is proposed
                 (USEPA, 1991). These sources are categorized into 15 "minor wastes" that include desalinization unit
                 discharge, blowout preventer (BOP) fluid, laboratory waste, ballast/bilge water, nonconuict cooling water,
                 seafloor contamination, uncontaminated seawater used for a variety of operations, boiler blowdown, excess
                 cement slurry, diatomaceous earth filter media, painting wastes, uncontaminated freshwater, accidentally
                 discharged bulk transfer materials, waterflooding discharges, and test fluids. More information on these waste
                 streams can be found in USEPA!s (1991) Development Document for Effluent Limitation Guidelines and
                 Standards for the Offshore Subcategory of the Oil and Gas Ertraction Point Source Category.

                 (d) Production SandslSolidslEquipment

                      Solid wastes discussed here include production sands, salvaged and discarded tubular pipes, pipe scale, and
                 tank bottom sludge. Other solid wastes such as oil-field equipment (used filters, drums, etc.), cement bags,
                 crates, plastics, and a variety of domestic wastes are discussed in Section IV.A.2.d.(5)(f), under Trash and
                 Debris.
                      Produced sand and other solids, such as scale, corrosion by-products, and parrafin, associated with oil and
                 gas productionare gravimetrically separated out of the production stream and accumulate in production tubing,
                 flowlines, and various oil and gas process vessels. These solids are removed periodically to improve production.
                 Low volumes of these fine sands may be drained into drums on deck or are carried through the offy water
                 treatment system and appear as suspended solids in the produced-water effluent or settle out in treatment
                 vessels. Due to the off-wetting of clay particles and the presence of paraffin, grease, and other hydrocarbon-
                 containing materials that are in various quantities in tank bottoms, tank bottoms are often referred to as
                 sludges. If sand volumes are larger, the solids are removed in cyclone separators, producing a solid phase
                 waste. Produced sands are, in reality, a mixture of many different kinds of solids. The primary component is
                 sand (SiO2), with varying amounts of mineral scale, corrosion products, and other formation fines. The
                 principle contaminants of concern in the sludge or sand mixtures are oil and NORM. The majority of tank
                 bottoms have measurable radioactivity levels at or slightly above background levels. However, instances of tank
                 bottoms having radioactive isotope concentrations as high as 2,000 picoCuries per gram (- Ci/g) have been
                                                                                                                1p
                 documented. The Offshore Operators Committee recently surveyed radium in produced sand from 30 OCS
                 locations in the Gulf and found Ra-226 levels averaging 47 pCi/g (Offshore Operators Committee, 1991).
                      The natural Ra-226 activity in Louisiana surface waters is below 1.0 pCi/l; for Louisiana soils, levels range
                 from less than 1.0 to 7.0 pCi/g. Ra-226 levels for openocean waters and marine sediments average 2 pCi/I and
                 1-17 pCi/g, respectively.
                      Industry has estimated that, historically, about 20-25 percent of production solids have been cleaned of oil
                 and grease contaminants and discharged overboard. The other 75-80 percent of production solids were brought
                 onshore for disposal. However, because of the recently recognized NORM contamination in these compounds,
                 previous disposal practices have been abandoned and a number of disposal methods are being considered.
                 Disposal methods are discussed above in Sections IV.A-2.d.(5) (offshore disposal) and IV.YL3.c.(4) (onshore
                 disposal).
                      Realizing the uncertainty of the regulatory climate regarding produced sands, this EIS assumes, for
                 analytical purposes, that no produced sands will be discharged offshore and that all will be brought onshore.
                 Estimates of total produced sand expected from a platform are from 25 to 250 bbl per day, according to the
                 USEPA (1991), or 5 percent of the oil produced (USEPX 1976). Total volumes of produced sands generated
                 from oil and gas production associated with the proposed actions are projected to be 69,000 and 154,000 bbl












                                                                                                                             IV-33

                in the CPA, Base Case and High Case, respectively-, and 24,000 and 64,000 bbl in the WPA, Base Case and
                High Case, respectively.
                    Not all scale is removed from equipment and disposed of with produced sands. Scale is a hard, rock-like
                flow restrictive substance that may form and adhere to downhole tubulars and in association with above-ground
                processing and transparent equipment and piping. As wells and facilities reach the end of their economic life,
                plugging and abandonment procedures are performed on the wells, and the production facilities are removed.
                Pipes removed from the wells and the process equipment may have accumulations of scales within. These
                scales may contain Ra-226 and Ra-228 in concentrations averaging 0.1-2,800 pCi/g. Some of these levels have
                been measured as high as 100,000 pCi/g. Presently, such accumulations prohibit the sale of this equipment
                either as scrap metal or for reuse in ways other than which they were originally intended. Therefore, these
                tubular goods must be cleaned to remove the contaminants before the transfer of ownership. Once removed,
                the contaminated wastes are returned to the operators for appropriate disposal. Because of the cost involved
                in contaminant removal, many operators have elected to stockpile the tubulars and process vessels at operator-
                owned facilities or nonhazardous oil-field waste (NOW) sites until a cost-effective method of radioactive scale
                removal is found.

                (e) Treated Sanitary and Domestic Wastes

                    Domestic wastes are wastewaters originating from sinks, showers, laundries, and galleys, as wen as
                wastewater from safety shower and eye-wash stations and fish-cleaning stations. Domestic wastes also may
                include solid materials (paper, boxes, etc.) that are combustible. These solid materials, defined as trash and
                debris, are not regulated under the NPDES process and are discussed in Section IV.A.2.d.(5)(f). Sanitary
                wastes are composed of human body wastes from toilets and urinals. Some platforms combine sanitary and
                domestic wastewaters for treatment; others maintain sanitary wastes separately for treatment by an approved
                marine sanitation device.
                    The volume and concentration of sanitary wastes win vary widely with time, occupancy, platform
                characteristics, and operation situation. In offshore operations, toilets are usually flushed with brackish water
                or seawater. Concentrations of fecal coliform bacteria serve as an indicator of the potential pathogenicity of
                water resulting from the disposal of human wastes. Specific levels of suspended solids and chlorine residual
                in an effluent are indicative of corresponding levels of fecal coliform. If the suspended-solid levels in an
                effluent are less than 150 mg/I and the chlorine residual is maintained at 1 mg/l, then fecal coliform. levels
                should be less than 200 per 100 ml. Properly operating biological treatment systems on offshore platforms have
                effluents containing less than 150 mg/I of suspended solids; therefore, chlorine residual is a reasonable control
                parameter. Domestic wastes contain no fecal coliform. so must only be ground up by a comminutor so that
                the discharge will not result in any floating solids.
                    In general, a typical manned platform will discharge 0.075  M3  per person per day of treated sanitary wastes
                and 0.110  M3  per person per day of domestic wastes (USEPA, 1991). Total volumes of discharges from all
                exploration, development, and production operations can be found in Tables IV-2 and IV-3. Not included in
                these figures are discharges from service vessels, which is estimated at 0.227  M3 per person per day (NERBC,
                1976). It is expected that such discharges are rapidly diluted and dispersed.

                (D Other Trash and Debris

                    Oil and gas operations on the OCS lead to the generation of waste materials made of paper, plastic, wood,
                glass, and metal. These wastes are collected and prepared for transportation and disposal onshore.
                Sometimes oil and gas trash is lost overboard from rigs and platforms or during transport back to shore.
                Through ingestion or entanglement, trash in the marine environment can adversely impact marine fish and
                wildlife resources and has been known to adversely affect navigation and fishing operations. Even when
                properly disposed of in approved landfills, this trash is contributing to the scarcity of available landfill space
                in adjoining State coastal areas.











                 IV-34

                      Human trash loads exceeding one ton or more per mile continue to be reported from coastal cleanups
                 along Texas and Louisiana beaches, adversely affecting the recreational ambience of the beach environment.
                 Beach users and other commercial and recreational users of the Gulf of Mexico are known to contfibute to
                 beach tra !sh and debris. Some items, however, clearly associated with offshore off and gas operations, can be
                 recognized among the beach litter along the Louisiana and Texas coasts. Items such as 55-gallon drums, 5-
                 gallon containers, paint cans, hard hats, pipe thread protectors, shrink wrap, stripping lumber, wooden pallets
                 and wire spools, empty mud chemical sacks, plastic and glass containers, large pieces of styrofoam, and
                 cardboard boxes are common items recognized on coastal beaches. Possible sources include drilling rigs,
                 production platforms, workboats, crewboats, supply or service vessels, oil barges, shuttle tankers, pipe-laying
                 barges, and geological, geophysical, or environmental research vessels associated with the proposed actions.
                 Because deliberate offshore disposal of solid waste is prohibited from offshore oil and gas operations, it is
                 assumed that only the accidental loss of trash and debris from all phases of OCS operations associated with
                 the Base Case and High Case scenarios from proposed Sales 142 and 143 will contribute sorrke solid wastes to
                 the Gulf of Mexico. Most of the trash generated by offshore oil and gas operations will be returned to shore
                 for disposal in approved landfill sites. A small amount of the trash generated offshore will be incinerated
                 offshore, but the practice is decreasing because of safety considerations and more stringent environmental
                 regulations.

                 (6) Air Emissions

                      Offshore air emissions related to the proposed actions result from platform operations; drilling of
                 development, exploration, and delineation wells; helicopters, service vessels, shuttle tankem, and barging of
                 crude off. These emissions occur mainly from combustion or burning of fuels and natural gas and from venting
                 or evaporation of hydrocarbons. The combustion of fuels occurs primarily on diesel-powered generators,
                 pumps, or motors and from lighter fuel motors. Venting or evaporation of hydrocarbons occurs during loading,
                 storage, and transporting of crude oil. Other air emissions can also result from catastrophic events such as oil
                 spills and blowouts.
                      The OCS offshore infrastructure contributing to air emissions includes platforms and well drilling rigs.
                 Primary air pollutants associated with OCS activities are nitrogen oxides (NO,), carbon monoxide (CO), sulphur
                 oxides (SO.), volatile organic compound (VOC), and suspended particulate (TSP). Ozone, a secondary air
                 pollutant, is not emitted by sources; it is the result of photochemical reactions in the atmosphere. Emission
                 of primary pollutants from OCS platforms and drilling operations are estimated using the emissions factors
                 shown below. These emission factors were developed from a 1985 MMS inventory of offshore OCS structures.
                 Emission factors are expressed in tons per year per platform (which implicitly assumes that an average OCS
                 platform can be defined) and in tons per well over 45 days. The most emitted pollutant are nitrogen oxides
                 derived mainly from the diesel-powered motors.

                                   Average Annual Emissions from OCS Infrastructures in the Gulf of Mexico

                                                      NO              CO             so             VOC              M10

                          Platforms (t/p/y)          85.75            11.17          0.15           32.50            0.21
                          Expl. Well (t/45-d)l         9.67            2.58          1.13            0.97            0.28
                          Expl. Well (t/45_d)2         7.16            1.91          0.84            0.72            0.21

                          Source: USDOI, MMS, Gulf of Mexico OCS Region estimates, 1989.

                            Assumes a 13,500-ft hole, 597,120 horsepower hour (hphr) diesel reciprocating engines, and
                            45-day drilling period.
                          2 Assumes a 10,000-ft hole, 597,120 horsepower hour (hphr) diesel reciprocating engines, and
                            45-day drilling period.












                                                                                                                                 IV-35

                   Emission factors of primary pollutants for accidental releases of oil or blowouts are presented below.
               These catastrophic events generally produce high-level emissions over a very short time in a localized area.
               Events such as oil spills or blowouts, with or without fire, are nonroutine in nature and are unpredictable. The
               release of air pollutants from oil spills is high during the first hour and decreases rapidly thereafter. It is
               assumed that emission of air pollutants from oil spills cease completely after three days. A blowout resulting
               in a gas discharge without fire releases only petroleum hydrocarbons and hydrogen sulfides, if present. If the
               blowout occurs with fire, combustion by-products, including all primary pollutants would be released. Blowouts
               are estimated to occur at a rate of about 7 per 1,000 wells drilled. Under the Base and High Case scenarios,
               4 and 8 blowouts (Table IV-2) are assumed to occur in the CPA, respectively. In the WPA, the number of
               blowouts assumed to occur in the Base and High Cases are 2 and 5, respectively (Table IV-3). These blowouts
               will not be associated with oil spillage greater than 50 bbl. Section IV.A.2.d.(8) discusses the risk of oil spills
               occurring with blowouts.

                                                   Emissions Associated with OCS Accidents
                                                                    (tons/hour)

               Accident lype                           THC*          NQ,               Sol,              CO                  PM10

               140-bbl spill
                First hour                               4.0
                Second hour                              2.0


               10,000-bbl spill
                First hour                             285.0
                Second hour                            145.0


               Blowout-No fire**                       1.0
               Blowout-With fire"                      0.34          0.02              0.21              534                 0.07

                *THC's are used as VOC emissions.
               "Assumes a blowout of 1,000 Mcf/d (gas) and 1,000 BPD (oil).

               Source: USDOI, MMS, 1983.

                   Emissions of air pollutants during loading, storage, and transporting of crude oil and gas are calculated
               using the methodology and emissions factors presented in USEPA publication AP-42 of 1985 with supplements
               A, B, and C. Helicopter emissions are also calculated using the methodology of USEPA publication AP-42,
               since helicopters land and take off from platforms and are by law part of the platform emissions. For purposes
               of calculation, each platform is assumed to be visited 1.5 times per day by helicopters. The total number of
               helicopter trips are shown in Tables IV-2 and IV-3. Helicopter type is a factor that needs to be considered
               when calculating their emissions.
                   The total amount of air pollutants emitted as a result of the proposed actions, Base and the High Case
               scenarios, are presented in Tables IV-2 and IV-3.

               (7) Noise

                   Noise emissions resulting from OCS oil and gas development are associated with the operation of offshore
               platforms, drilling rigs, seismic surveys, and helicopter and service-vessel traffic. Noise emissions associated with
               these activities are variable and may be loud or soft, transient or constant. Noise emitted from activities
               associated with the proposed actions may affect resources proximate to the activities. Helicopters and service
               vessels are the primary mode of transporting personnel and equipment between shore and offshore platforms.









                 IV-3@

                 Noise from these transient sources may affect birds, marine mammals and turtles, and recreational beach users.
                 Noise from offshore seismic surveys is transient but may startle marine mammals and turtles proximate to the
                 generated pulse. Noise from offshore development and production will be of a longer terin and may affect
                 marine mammals and turtles.
                     Macl@liiiery noise sources found on drilling and production platforms are generally similar to those used for
                 shore-based operations. Special noise attenuated devices are sometimes used on offshore platforms to protect
                 workers in their living quarters. Compressors and diesel engines are typically the loudest equipment on
                 platforms, emitting about 90 decibels (dB) at a distance of 15 in (50 ft). By comparison, a diesel truck under
                 full load also emits about 90 dB at 15 in. Other sounds, such as the banging of pipes or platiforin noises, may
                 also degrade the underwater acoustic environment. Gales (1982) points out that in light seas the subsea surface
                 noise propagated by a platform could be detected up to 100 mi away. In a quiet sea with light wind conditions,
                 normal offshore platform operations would be inaudible beyond about 2 mi (assuming an ambient background
                 noise level of 40 dB and attenuation due to sound wave spreading only). In rough seas and weather conditions,
                 the offshore facility would be inaudible beyond about 1/8 of a mile (assuming a 70-dB background).
                     The Acoustic Society of America (1980) has estimated maximum sources levels at 230-250 dB relative to
                 micropascal at 1 in for various types of activities associated with seismic exploration. These are classified as
                 the highest sound pressure levels associated with offshore oil and gas explorations; the pulses are of short
                 duration (generally less than 1 second) and are generated intermittently for relatively short survey periods (on
                 the order of a few months in any given area) (Gales, 1982). Seismic surveys also may be interrupted for a
                 period of several hours or days. Received-noise levels will be less than produced levels, and the rate of decay
                 will depend on bottom absorption ability, the type of spreading (cylindrical or spherical), and other physical
                 factors. Even with the maximum pressure levels estimated for seismic arrays a re/micropascal), the sound
                 pressure level is expected to be under 200 dB at distances beyond 100 yd (Gales, 1982). It is assumed that
                 noise generated from seismic surveys as a result of the proposed action will occur only from airgun-generated
                 pulses.
                     Helicopter and service vessel traffic produce noise of a transient nature. The noise level[ produced in the
                 air or on the water varies greatly with the type, size, speed, etc. of the moving object. To ensure the protection
                 of endangered and threatened species, environmentally sensitive coastal areas, and the aesthetic value of
                 recreational beaches, the Helicopter Safety Advisory Conference (HSAC) published an information booklet,
                 which was distributed to helicopter operators, pilots, and users in the Gulf of Mexico (Helicopter Safety
                 Advisory Conference, 1991). The HSAC booklet states that "all aircraft (fixed-wing or rotor) maintain a
                 minimum of 2,000 feet above the surface of all National Parks, Monuments, Seashores, Lakeshores, Recreation
                 Areas, Scenic Riverways, National Wildlife Refuges, Big Game Refuges, Game and Wildlife Ranges and
                 Wilderness Primitive Areas." In addition, the Federal Aviation Administrative (FAA) Advisory Circular 91-36c
                 encourages pilots making flights near sensitive areas or near locations of endangered or threatened marine
                 animals to fly at altitudes higher than the minimum permitted by regulation and on flight paths that will
                 eliminate interaction or reduce noise in such areas. The HSAC booklet provides all necessary maps of
                 applicable areas in the Gulf. It is assumed that helicopter traffic as a result of the proposed action win adhere
                 to the recommended flight ceilings and special prohibitions.
                     Service vessel traffic slows as it approaches coastal areas and inland waterways, thereby significantly
                 decreasing noise emission in sensitive coastal areas and near recreational beaches (USDOT, CG, 1991). It is
                 assumed that service-vessel traffic as a result of the proposed action will adhere to Coast Guard regulations,
                 will use existing ports areas, and will slow as they approach the coastline. Offshore, it is assumed that service-
                 vessel traffic has the potential to elicit a short-term startle reaction from marine mammals and turtles.
                 However, most species of cetaceans, such as bottlenose and spotted dolphins, deliberately seek out and travel
                 with vessels in the Gulf.


                 (8) Blowouts

                     Improperly controlled well pressures can result in the sudden, uncontrolled escape of petroleum
                 hydrocarbons. Such an incident is referred to as a blowout The loss of control can be momentary or could












                                                                                                                               IV-37

               last for hundreds of days. The longest time recorded for a blowout in the Gulf of Mexico OCS was 156 days.
               Blowouts have caused the greatest number of fires, explosions, deaths, injuries, and property damage or loss
               on offshore rigs or platforms; can result in significant air and water pollution incidents; and have resulted in
               costly delays in drilling and production programs (Danenberger, 1980; Fleury, 1983).
                   Blowouts can occur during any phase of oil development: exploratory drilling, development drilling,
               production, and workover operations. Since 1971, MMS has maintained a data base on blowouts. This
               database includes information on the causes and extent of damage from the blowout event. During the time
               period 1971-1989, there were 116 blowouts (USDOI, MMS, 1991b). Thirty-four percent occurred during
               exploratory drilling, 28 percent during development drilling, 10 percent during well completions, 9 percent
               during production, and 19 percent during workover operations. Sixty-three percent of the oil spilled from these
               operations was during production.
                   To estimate the number of blowouts that could occur from the proposed actions, the number of wells
               drilled was correlated with the number of blowout events during the time period of 1975-1989. It is estimated
               that about 7 blowouts will occur per 1,000 well starts.       Tables IV-2 and IV-3 provide the total numbers
               projected over the life of the proposed action.
                   Because there have been several large spills in the Gulf of Mexico and elsewhere areas associated with
               blowout events (the Santa Barbara Blowout and the Mexican Ixtoc blowout), the biggest concern associated
               with blowout events is often the potential for oil spills. An analysis of MMS blowout and oil-spill data shows
               that between 1958 and 1986 only about 23 percent of reported blowouts resulted in some oil spilled and about
               8 percent resulted in spills of 50 bbl or greater. Only 4 percent resulted in spills over 1,000 bbl (USDOI, MMS,
               1988b). Potential spills from blowouts are accounted for in our platform spill estimates provided in Section
               IV.C. It is assumed that there will be no oil spills greater than 50 bbl resulting from the projected blowouts.
                   Blowouts can also disturb both archaeological and biological resources due to sediment resuspension and
               explosive impacts. Deep-water benthic communities, topographic features, and live-bottom areas can be
               affected by blowouts, as well as offshore water quality and air quality.

               (9) OffNhore Spi&

                   The OCS hydrocarbon development creates concerns about crude oil, diesel, and condensate spills. A spill
               event can occur on OCS waters and, because of oceanographic and meteorological processes, it can be
               transported to nearshore or coastal areas. Besides spills, there are chronic leaks from facilities, transportation,
               and or processing facilities. Tnese leaks are, in general, less than or equal to 1 bbl. Materials that can be
               spilled during the activities include crude oil, condensate, diesel, and other pollutants. These spill events occur
               in a random fashion in time and space. Any attempt to describe these random processes must, therefore, use
               statistical procedures and techniques. Section IV.C. presents a discussion of the statistical techniques, rates,
               probabilities, and assumptions about spills in offshore areas. Also, the section presents details of historic
               occurrence of spills, processes, and characteristics of the spills disscussed in this document. The projected
               number of oil spill occurrences of different size categories under the Base and High Case scenarios in the CPA
               and WPA is shown in Tables IV-2 and IV-3.
               3. Description of Onshore/Coastal Operations and Impacting Factors

                   Numerous onshore facilities and activities are needed to support offshore oil and gas operations. Service
               facilities (service bases and heliports) are used as transfer and loading sites for the movement of supplies and
               personnel to offshore work locations. Construction facilities (platform fabrication yards and pipeyards)
               assemble and prepare the structures that are used to develop and transport hydrocarbons. Processing and
               storage facilities (terminals, separation facilities, gas treatment plants, and refineries) provide temporary storage
               sites for hydrocarbons, remove various impurities from the hydrocarbon stream, and separate and distill various
               hydrocarbon fractions from the raw product.
                   Impacts from onshore infrastructure can result from the construction of new facilities, the operation of
               existing facilities, and transportation activities to and from the infrastructure sites. This documentassumes that












                  IV-38

                  no new facilities will be constructed as a result of the Base or High Case scenarios. The specific reasons why
                  this assumption is made for each infrastructure type are discussed in the sections that follow-. These sections
                  also briefly describe the kinds of impacts that could occur as a result of the ongoing operation of these facilities.
                      Numerous other activities occur onshore and within coastal waters in association with OCS oil and gas
                  operations. These activities include the movement of oil via pipeline, barge, and shuttle tanker; the offloading
                  of off at terminals; service vessel and barge traffic through coastal waters; helicopter flight patterns over the
                  coast; onshore oil spills; and the onshore disposal of offshore wastes. The projected maipitudes of these
                  activities and quantities are shown by coastal subareas (Figure IV-1) in Tables IV-4, IV-5, and IV-6.

                  a. Onshore Infrastructure

                  (1) Serpice and Construction Facilities

                  (a) Service Bases

                      The total number of service vessel trips expected to result from the proposed actions under the Base and
                  High Case scenari6s is shown in Tables IV-2 and IV-3. Service base locations in the Central and Western Gulf,
                  and the waterways that provide access to these bases, are indicated in Table IV-6. Table IV-6 also shows the
                  projected number of service vessel trips to these bases as a result of the Base and High Case scenarios. The
                  distribution of vessel trips to the various service bases was derived from an analysis of the historical records
                  of service base usage by OCS-related traffic. Activities associated with the Base and High Case scenarios are
                  assumed to account for 3 and 7 percent, respectively, of the utilization of the service bases listed in Table IV-6
                  during the 35-year life of the proposed actions.
                      No new service base construction is projected under the Base and High Case scenarios. This assumption
                  is based on the widespread distribution of existing service base facilities throughout Texas and Louisiana and
                  on the ability of the existing service base capacity to support levels of OCS activities in previous years that
                  exceed the levels projected during the life of the proposed action. While the proposed actions are associated
                  with increased off and gas activities in deep-water areas of the Gulf, which may utilize larger service vessels
                  than have been traditionally used for OCS operations, this document assumes that existing fac:Mties can be used
                  either as they currently exist or with modifications to the navigation channels that provide access to the service
                  bases. (Navigation channels are discussed in Section IV.A.3.b.(3) below.)
                      It is assumed that each service base can support 6 mobile rigs or 20 platforms. Each service base is
                  assumed to occupy 12 ha of land. Service bases are located adjacent to navigation channels that provide easy
                  access to offshore waters Of the Gulf.
                      Offshore oil and gas exploration, development, and production require onshore support ftom bases serving
                  as the transfer point for materials and personnel. A supply base is used for transferring heavy equipment and
                  supplies (machinery, drilling muds, cement, drilling water, etc.) to boats. It provides facilities for boat dockage,
                  fuel storage, loading/unloading, warehousing, open storage, and parking. Personnel and light equipment
                  disembark from a crew base. Crew bases can be located at the same site as a supply base, or at a separate
                  facility. A crew base located at a separate pier includes a pier, parking, and security arrangements at a
                  minimum. Crew and supply bases operate 7 days a week throughout the year (Centaur Associates, Inc., 1985).
                  A service base is assumed to occupy 16 ha (40 ac) of land.
                      Environmental impacts associated with normal service-base use include runoff and spillage of fuels and
                  chemicals from the facility, discharges from supply and crew boats, channel-bank erosion from vessel traffic,
                  and disturbance of bottom sediments and communities if dredging is required to maintain channel navigability.
                  There will be no impacts from new construction activity because no new service-facility construction is projected
                  in support of the leases that may result from the proposed actions.












                                                                                                                             IV-39

               (b) Heliports

                    A total of 325 heliports, or designated areas where helicopters can land, have been built and are used
               throughout the coastal areas of the CPA and WPA to accommodate the transportation needs of oil and gas
               operators moving people and, occassionally, equipment between shore and offshore work locations. As of 1990,
               there were 33 operating helicopter hubs, or major base locations, in the coastal areas of Louisiana, Texas, and
               Alabama. Most hubs (21) are located across coastal Louisiana. Eleven others are located in the Texas coastal
               area and 1 in coastal Alabama. Helicopter hubs in the CPA and WPA accommodate up to 46 helicopter pads.
               Under the Base and High Case scenarios, it is assumed that 3 and 8 percent, respectively, of existing heliport
               capacity is attributed to OCS operations.

               (c) Pipeyards

                    The number of existing pipeline coating yards in the Central and Western Gulf is 9 and 8, respectively
               (Table IV-14). No new pipeline coating yards are projected to be constructed under the Base or High Case
               scenarios. The basis for this assumption is that current capacity can accommodate up to 1,440 km (900 mi)
               of pipeline installations per year, based on the lengths of offshore pipelines that have been installed in recent
               years. Projected new pipeline lengths under the Base and High Case scenarios will not result in this capacity
               being exceeded. Furthermore, during the past two years, four pipeline coating yards have closed in the Gulf
               area, indicating current overcapacity at pipe coating yards. Industry also does not foresee new expansion in
               these facilities (Jones, personal comm., 1991).
                    Because of the low cost of transporting coated pipe compared to the cost of the pipe, existing pipeyard
               locations can economically service pipeline projects in any area of the Gulf. There is not economic grounds,
               therefore, to construct new pipeyards in coastal areas with locational advantage to new pipeline projects
               offshore but currently having no existing facilities, such as in offshore Subarea C-4 or the southern part of W-3
               (Figure IV-1). Under the Base and High Case scenarios, respectivley, two percent and three percent of the
               utilized capacity of pipeyards in the Gulf will be associated with OCS operations.
                    These facilities store and coat pipe that will be used for offshore pipelines. The external surfaces of pipes
               are coated with metallic, inorganic, and organic materials. These materials protect the pipe from external
               corrosion and abrasion and add weight to counteract buoyancy with a concrete coating. Although some pipes
               are coated on a lay barge as the pipe is being installed offshore, most coating occurs at an onshore facility.
                    Pipeyards are assumed to occupy 12 ha (30 ac) of land and can store up to 200 km (124 mi) of pipe. Most
               of the space needs of a yard (up to 95%) are for storing untreated and treated pipe. During some stages of
               the coating process, treated pipe may have to cure in storage for 3 weeks or more before it can be moved.
               The yards must be located along a navigable waterway that has an access channel with at least a 4.5-m (15-ft)
               draft. The major environmental impacts from pipeyard operations include water and air discharges from the
               coating process. Waste waters from a pipeyard can contain antifouling chemicals and a variety of contaminated
               process waters. Air emissions containing carbon monoxide, sulfur and nitrogen oxides, and particulate can
               occur as a result of routine processing operations, from leaks at seals and valves on storage tanks, and from
               vehicle emissions.

               (d) Fabrication Yards

                    The number of platform fabrication yards located in the various coastal subareas in the CPA and WPA
               are 14 and 11, respectively (Table IV-14). No new platform fabrication yard construction is projected for the
               Base and High Case scenarios for the proposed actions. The bases for this assumption are the overcapacity
               of platform fabrication facilities in the Gulf, as witnessed by the closure of eight yards and the temporary idling
               of three more in the past few years, the increasing consideration being given by industry to the use of floating
               production facilities in deep-water areas, and a trend toward purchasing tension-leg platform hulls from
               overseas.











                IV-40

                     Platforms used in the development of offshore oil and gas fields are fabricated and assembled at platform
                fabrication yards and then towed to their offshore sites for installation. These platforms con:;ist of an above
                and below water component, called the deck and the jacket, respectively. These components may be
                constructed at the same or at different yards. Because of the large size of these structures, access to a large
                navigation channel is of prime importance in the location of these facilities. As indicated in Table IV-14, the
                largest number of platform yards occur in coastal Subarea C-2, which includes the Atchafalaya River, a large,
                wide navigable river.
                     The primary activity at these yards is the shaping, cutting, and welding of the steel components of the
                offshore structure. Because of the size of the structure being constructed and the need for storage space for
                large amounts of steel, a platform fabrication yard typically occupies a large amount of coastal land. In this
                document, each fabrication yard is assumed to occupy 50 ha (124 ac). Three and five percerit of the utilized
                capacity of fabrication yards in the Gulf are assumed to be associated with the Base and High Case scenarios,
                respectively.
                     The main environmental impacts from the routine operation of these facilities include the discharge of
                waste waters and storm runoff that may contain heavy metals and particulate and the discharge of air emissions
                that include sand and metal dust from sandblasting operations, hydrocarbons and organic compounds from
                paint evaporation, and carbon monoxide and sulfur and nitrogen oxides from equipment and vehicle operations.
                In addition, solid wastes containing metal scraps and debris will have to be disposed of.

                (2) Processing and Storage Facilities

                (a) Oil RejIneries

                     The number of existing refineries in the Central and Western Gulf are 17 and 20, respectively (Table IV).
                No new refinery construction is projected as a result of the Base and High Case scenarios (Table IV-9).
                Sufficient refinery capacity exists in the area to accommodate OCS production from the proposed actions.
                Furthermore, because of the large capital expenses of establishing a new refinery, it is likely that, if needed,
                additional refinery capacity in the Gulf will be provided by increasing the capacity of existingrefineries rather
                than constructing new facilities. These assumptions are consistent with the national trend in refinery operations
                during the past decade, which has shown a decrease in the number of refineries since 1981 from 324 to 202
                (U.S. Dept. of Energy, 1991a). The Department of Energy (1991b) predicts little expansion of crude oil
                distillation capacity nationwide through the year 2010, based on increasing foreign competition in the refined
                oil products market and the regulatory difficulties of building new refineries near existing facilities because of
                new air quality legislation. Under the Base and High Case scenarios, I and 2 percent, respectively, of the
                utilized capacity of refineries are assumed to be associated with OCS activities.
                     A refinery separates the naturally occurring components of crude off into marketable products such as
                diesel fuel, lubricating off, and gasoline. The refining process includes a number of interdependent operations
                that receive crude oil; it separates the off into components and then blends the components into
                petroleum-derived products. Large tracts of land are needed for a refinery to allow sufflicient space for
                expansion and a buffer zone. In the Gulf area, each refinery complex occupies on average 405 ha of land.
                Factors that are considered in locating a refinery site are the availability of large quantities of water and the
                accessibility of nearby deep-water facilities for large crude-off carriers.
                     In the Gulf of Meidco area, either oil is delivered directly to refineries from the OCS via pipeline or barge,
                or it is first delivered to an oil terminal via pipeline or barge and then piped, barged, or trucked to a refinery.
                Barge traffic makes extensive use of the Intracoastal Waterway and other inland waterways for transporting
                oil from terminals to refineries.
                     Impacts from routine refinery operations include visual and aesthetic degradation; air emissions including
                particulate matter, nitrogen and sulfur oxides, carbon monoxide, and volatile hydrocarbons; and waste-water
                discharges including hydrocarbons,. alkaline substances, particulate, and metal fragments. In addition, the
                unloading of barges and trucks at a refinery introduces the chance of an accidental oil spill.












                                                                                                                                IV41

                 (b) Gas Processing Plants

                     The number of existing gas processing plants in the Central and Western Gulf that process OCS
                 hydrocarbons are 26 and 2, respectively (Table IV-8). These gas processing plants are assumed to be
                 exclusively devoted to processing OCS production. The high concentration of processing plants in the western
                 part of the Central Gulf (coastal Subareas C-I and C-2) is related to the occurrence of gas-prone tracts in
                 nearby offshore areas.
                     It is assumed that the existing capacity of gas processing plants will be adequate to handle all new gas
                 production under the Base and High Case scenarios. Presently, only 64 percent of the gas processing capacity
                 of OCS-related facilities is being used. The decision to construct a new gas processing facility at a new
                 pipeline landfall location would be based on numerous factors, such as the proximity to an existing facility, the
                 quantity of gas available for processing, the composition of the gas (particularly with respect to the amount of
                 valuable liquid components and impurities such as C02 and H2S), and the current and projected market
                 conditions for gas and gas products. No new pipeline landfalls, however, are projected to occur under either
                 the Base or High Case scenarios.
                     Gas processing plants remove impurities from raw gas to preset standards of the purchasing utility before
                 the gas is commercially distributed. Initial processing of the gas can take place at the production platform to
                 remove oil and/or water prior to reaching the processing plant. Some processing plants are constructed to also
                 recover certain saleable natural gas liquids such as butane, propane, ethane, and natural gasoline from
                 condensate if these components are present in quantities that make extraction economically feasible. Liquids
                 are removed from the gas stream by a process that cools the gas through refrigeration or through a
                 lean-off-absorption process. A gas plant can be located either at the shore or farther inland. A site near the
                 coast is preferred because the greater distance that offshore gas travels through a pipe the more cooling will
                 occur. Cooling can lead to the formation of hydrates in the line; this can obstruct the gas flow. Gas is delivered
                 to and transmitted from processing plants via pipeline.
                     Land requirements for a gas processing plant are usually not large. Estimates are that a l-MMcfd facility
                 requires 20-30 ha (50-75 ac). Typically, in the Gulf, gas processing plants constructed to process OCS gas have
                 been larger than plants constructed for onshore production. The average design capacity for existing OCS
                 plants is 570 MMcfd compared to 151 mmcfd for facilities processing onshore production. There are no
                 standard sizes or designs for a gas plant, however, because the plant is specifically designed for the particular
                 gas stream it processes. The life span of a plant is usually 10-20 years, depending on the longevity of the gas
                 reserves being processed.
                     The primary environmental effects of a gas processing plant include gaseous, liquid, and solid-waste
                 discharges. Primary air emissions include sulfur and nitrogen oxides, hydrogen sulfide, carbon monoxide,
                 volatile hydrocarbons, and particulate. Waste-water discharges can include dissolved hydrocarbons; sulfuric
                 acid; and chromium, zinc, phosphate, and sulfite compounds. Solid wastes are composed of sludges, scales,
                 spent desiccants, filtration media, and oil absorbents.

                 (c) Separation Facilities

                     No new facilities are projected for the Base or High Case scenarios of the two proposed sales. The existing
                 facility capacities and locations are considered sufficient to support any usage projected from processing oil and
                 gas produced as a result of the proposed actions. It is projected that any water-separation operations required
                 as part of proposed Sales 142 and 143 activities will use about 3 percent of the capacity of the existing facilities
                 under the Base Case, and 6 percent under the High Case scenario. Table IV-14 lists the subarea locations of
                 the existing 63 separation facilities handling OCS oil along the Gulf Coast. Fifty of these existing facilities are
                 located within Subareas C-1, C-2, and C-3 of the Louisiana coastal zone. About 6 ha (15 ac) are required for
                 each 100,000 bbl of oil and associated gas processed.
                     Separation facilities, frequently called partial-processing facilities, are often located with terminals and/or
                 gas processing facilities. Separation occurs to remove impurities from the crude oil or gas received at the
                 terminal. Crude oil and gas coming directly from an offshore well must be separated and the water removed











                IV42


                prior to being processed for final disposition. The liquid components of the well stream are partially processed
                to remove free and emulsified water, dissolved solids, and suspended solids from the crude off. Once the crude
                oil is partially processed, it is delivered to a refinery for conversion into a range of petroleum products. The
                separation process may begin on the offshore platform and continue with further separation and treatment at
                onshore processing facilities; however, the process may take place totally offshore. Natural; as is often, but
                not necessarily, removed on the platform and handled at separate facilities.
                    Impacts from separation facilities are limited to the usage of the existing facilities. They include air
                emissions; the discharge of cooling and boiler waters, and domestic wastewaters; storm runoff, and noise.
                Hydrocarbons, hydrogen sulfide, sulfur oxides, and nitrogen oxides are the primary types of air emissions.
                Sources include evaporation from surge and storage tanks, combustion products from process machinery and
                vehicles, and leakage at valves and seals. Major water-quality contaminants discharged include suspended
                solids, oil and grease, heavy metals, phenols, halogens, and chromium. Noise levels can be as high as 96 dB
                from flare stacks and treating vessels.

                (d) Terminals

                    Terminals are defined as the receiving station for liquid hydrocarbons transported from offshore platforms
                to shore. Most terminals are the landfall site of a pipeline, where a metering station is located and where
                storage facilities are expected to be found. Terminals can occur in association with a gas processing plant if
                liquid hydrocarbons are being extracted from the gas stream. Most of the 94 terminals receive hydrocarbons
                by pipeline. Only a few receive oil by barge. Oil projected to be shuttle tankered may be received by one of
                these 94 terminals if there are docking facilities present (many already receive imported crude oil tankers) or
                it may go directly to the terminal facilities connected to nearby refineries. Some of these terminals receive gas
                rather than oil. Gas processing plants and separation facilities are often associated with pipeline terminals.
                Once received, metered, partially processed, and stored at terminals, OCS crude off is then shipped to refineries
                via pipeline, barge, or truck.
                    The size of a terminal and tank farm depends on the production rate of the fields supplying the terminal
                and the throughput rate of the pipeline(s) serving the terminal, as well as the size of the tankers projected to
                use the facilities and the number of days it may be necessary to store the oil before throughput Most of the
                land required for a terminal and related tank farms is for the storage tanks. For example, a 1-MMbbl tank
                farm capacity requires 7 ha (17 ac) of land and a 35-MMbbl tank farm requires 23.5 ha (58 ac) of land
                (NERBC, 1976).
                    Because no trunklines are projected to transport oil or gas produced solely as a result ol"proposed Sales
                142 and 143 and because barging operations are projected to remain static, no new terminah, will be needed.
                Rather, about 12 percent of the capacities of the existing terminals are projected to be used to store and
                manage oil and gas coming ashore produced from Sale 142 and 143 leases under the Base Case, and 12 percent
                under the High Case. Table IV-14 locates by subarea the existing 94 terminals operating; along the Gulf
                coastline--80 of these are in Louisiana and 14 are in Texas.
                    Because no new marine terminals are projected to be built as a result of the proposed actions, there will
                be no impacts from the construction of new marine terminals. Impacts from existing marine terminals result
                from routine air and water operational emissions and runoff from the altered terrain. The magnitude of air
                emissions, as well as all other environmental impacts from the operation of a terminal and the: associated tank
                farm, will depend on the volume of delivery, types of storage tanks used, and operating equipment and
                procedures.
                    Sources of air discharges at a terminal include evaporation from storage tanks, evaporation from the
                transfer of crude oil and fuel, combustion products from process machinery and marine vessel;, and accidental
                small spills and leakage, as well as exhaust emissions from boaters, sumps, and compressors (NERBC, 1976).
                Marine terminals generate domestic wastewater from employee housing, bilge and ballast waters from vessel
                traffic, cooling and boiler waters from the generation of electricity, and storm runoff.












                                                                                                                           IV-43

               b. Landings and Coastal Transport Operations

               (1) Pipelines

                   Currently, 150 pipeline landfalls are located along the Louisiana coast and 19 along the Texas coast as a
               result of previous OCS development. No new pipeline landfalls or onshore pipeline projects are anticipated
               as a result of the Base and High Case scenarios. The basis for this assumption is covered in Section
               IV.A_2.b.(1). Briefly, it is assumed that the expense of installing an offshore trunkline and associated landfall
               requires development from more than one lease sale to be economically justified. It is assumed that production
               from the proposed actions will utilize the extensive existing pipeline network to route new hydrocarbon
               production through. Furthermore, the projected increased utilization of floating production systems and shuttle
               tankers in deeper waters will reduce the need for new pipeline landfalls.
                   Tables IV-4 and IV-5 show the projected amounts of liquid hydrocarbons that are assumed to be
               transported into the various coastal subareas of the Gulf as a result of the proposed actions. Most of the
               pipeline transported oil associated with proposed Sale 142 (86%) will be transported into and through coastal
               Subarea C-2. For proposed Sale 143, the pipeline transported oil is assumed to be more evenly distributed
               throughout the Texas coastal area, with a small amount arriving via pipeline in coastal Subarea C-2.
                   Pipeline landfalls are considered an impact-producing factor for several reasons. Installing and burying
               the pipeline in shallow nearshore waters can temporarily disturb bottom communities and seagrass beds and
               can increase coastal turbidity levels. Also, coastal scientists have postulated that the dredging of channels
               across coastal landforms, such as barrier beaches and wetlands, could alter coastal processes or create zones
               of weakness resulting in accelerated erosion or landscape changes in the vicinity of the landfall. Onshore, the
               dredging of pipeline canals results in the direct conversion of wetland habitat to open-water and spoil-bank
               habitats. The canals also can alter wetlands hydrology, resulting in wetlands impacts associated with saltwater
               intrusion and wetland water table alterations.

               (2) Oil Barges

               Landings

                   The number of projected barge trips from offshore platforms to onshore terminals for offloading is given
               for each coastal subarea in Tables IV4 and IV-5. These trips are referred to as offloadings in the tables.
               Subarea C-1 will receive the majority of barged oil. Table IV-6 breaks down these barge trips by utilized
               waterways and the specific terminals where the offloading is projected to occur. Six terminals in Lake Charles,
               Gibbstown, Weeks Island, Gibson, Cocodrie, and Empire, Louisiana are presently receiving OCS barged oil
               and are expected to continue to receive oil from platforms located in both the WPA and the CPA. Three
               terminals, all located in Subarea W-2 in Texas (at Texas City, Galveston, and Port Arthur) will receive WPA
               barged oil. In the WPA, the Houston Ship Channel, Sabine Pass Ship Channel, and the Calcasieu Ship
               Channel will be utilized by the barge traffic carrying WPA oil.

               Coastal Barging

                   The projected number of barge trips carrying OCS oil (Tables IV-2 through IV-6) represents barging from
               the production facility to terminals along the Louisiana and Texas coasts. It does not include barge traffic
               involving OCS oil between terminals or from terminals to refineries. Oil piped to shoreline terminals is often
               subsequently transported by barge up rivers, along the Gulf Intracoastal Waterway, and along the coast.
                   Impacts associated with coastal and inland barging activities are related to navigation channel usage,
               discharges from tugs pushing the barges, and possible spills. Once a barge carrying OCS-produced oil reaches
               coastal waters, the barge is often linked together with other barges; sometimes as many as three or four barges
               are pushed by one tugboat. Such activities increase channel-bank erosion. Crude oil spills from both the











                  IV-44

                  barging of OCS oil from platforms to the first offloading terminal and from the terminal along the coast are
                  projected (Section IV.C.1.).

                  (3) Shuttle Tankers

                  Landings

                      The number of projected shuttle tanker trips from offshore platforms to onshore terminals for offloading,
                  called oil landings, is given for each coastal subarea in Tables IV4 and IV-5. Table IV-6 shows the number
                  of shuttle tanker trips expected to occur along navigational channels going to major port areas. For the Base
                  Case scenario of Sale 143, there are 66 shuttle tanker trips projected. This traffic will carry oil from floating
                  production systems located in the WPA to onshore port areas. In Texas, there are projected to be 33 trips to
                  the Corpus Christi area, 9 trips to Freeport, 14 trips to the Houston area, and 5 trips to Port Arthur. In
                  Louisiana, 5 trips to Uke Charles and 2 trips to Mississippi River ports are projected. The two shuttle tanker
                  trips projected to occur while carrying oil from CPA floating production systems associated with proposed Sale
                  142 will offload along the Mississippi River.
                      No off is projected to be reloaded back on shuttle tankers and moved coastwise to other terminals.
                      Any environmental impacts from shuttle tanker activities in the coastal area is related to the risk of oil
                  spills (Section W.C.). The greatest risk of spill occurrence is at a terminal during offloading and onloading
                  operations.

                  (4) Navigation Channels

                      The OCS oil and gas industry uses the extensive waterway system located within the Gulf Coast States to
                  provide access between onshore support operations and offshore platforms and rigs. Vessels moving along
                  coastal navigation channels include crewboats, supply boats, barges, derrick vessels, geophysical-survey boats,
                  and floating production platforms, etc. Navigation channels serve as routes for service vessels traveling back
                  and forth from service and supply bases. Also, the channels may be traversed by barges carrying oil from the
                  OCS or between terminals, may be used for transporting platforms and pipelines, and may provide access to
                  oil-spill cleanup equipment stored at coastal ports. In this document, it is assumed for analytical purposes that
                  OCS-related facilities are located, on an average, 25 kin inland from the coast along a navigation channel.
                      Table IV-6 provides projections of the average usage of all major navigational channels along the Gulf
                  Coast in support of OCS activities as a result of the proposed actions. Six of these channels are used by the
                  OCS oil and gas industry more than 0.1 percent of the time: Bayou Lafourche, Empire Waterway, Bayou La
                  Loutre/St. Malo/Yscloskey, Vermilion Bay/GIWW 159-160, the Houma/LeCorpe/Caillou. waterway, Bayou
                  Terrebonne (Bayou Terrebonne usage is aggregated with the Houma/LeCorpe/Cafflouwaterway in Table IV-6),
                  and the Atchafalaya River/GIWW 79-95. All of these waterways are located in Louisiana. It is assumed that
                  OCS usage of these channels under the Base and High Case scenarios will account for 0.2 and 0.4 percent,
                  respectively, of the total vessel usage of these channels. The maximum percentage usage of a channel for OCS
                  activities as a result of the proposed actions is 2.2 percent for the Houma/Caillou/Terrebonne waterway.

                  c. Onshore/Coastal Impacting Factors Related to the Proposed Actions

                  (1) Disturbances fi-om Use of Existing Infrastructure

                      The infrastructure and facilties described above generate emissions and wastes that can affect the coastal
                  environment. Other activities associated with onshore infrastructure that could affect the coastal environment
                  include the movement of oil via pipeline, barge, and shuttle tanker; the offloading of oil at terminals; and the
                  use of navigation channels by OCS-related traffic.












                                                                                                                           IV45

              (a) Nonpoint Source Discharges

                  The operation of onshore facilities used in support of the proposed actions is expected to result in some
              routine nonpoint source pollution. The facility's presence, along with access routes, alters the natural hydrology
              and geography of the area over time. The volume and rate of stormwater runoff will remain greater than
              before construction; saltwater intrusion may occur; and, with existing vegetation modified, greater erosion
              around the facility may take place.
                  Increases of nonpoint source pollution due to runoff at support facilities may contribute particulate matter,
              heavy metals, petroleum products, chemicals, and radionuclides (particularly from pipeyards) to local streams,
              estuaries, and bays, causing temporary elevations in pollutant and turbidity levels. Two major pollutants are
              contained in this runoff--suspended solids (organic and inorganic) from exposed soil at the site and
              contaminants such as heavy metals.

              (b) Operational Discharges

                  The supporting existing infrastructure contributes routine and accidental point source discharges to the
              surrounding bodies of water. Specific contaminants in operational discharges are discussed under each facility
              description. At service bases and marine terminals, hydrocarbons and other pollutants are discharged in the
              bilge and ballast waters of support vessels docking at these facilities. The bases and support vessels also
              contribute contaminants through their use of antifouling marine paints, through accidental oil-spillage events,
              and through the release of heavy metals and contaminated sludge. Pipecoating yards, platform-construction
              facilities, and repair and maintenance yards contaminate surrounding waters by releasing thermal effluents,
              radioactive substances, antifouling paint chemicals, heavy metals, and a variety of process waters, as well as
              solid waste such as packaging materials, metal scraps, and other debris. Gas processing plants and refineries
              discharge a number of types of wastewaters, including cooling and boiler waters, sanitary and domestic
              wastewaters, and process waters. These waters maybe contaminated with dissolved hydrocarbons, sulfuric acid,
              chromium, zinc, phosphates, alkaline substances, and suspended solids.
                  Cooling water represents a significant proportion (70-100%) of the wastewater effluent from an oil refinery
              or gas processing plant. Chemicals added to the cooling water stream to reduce corrosion and fouling within
              the tower and the condenser system (including chromium and chlorine) may be extremely toxic to aquatic
              organisms. Domestic wastewater from support facilities will be collected and delivered to a municipal
              treatment plant or will receive secondary treatment in an onsite package treatment plant. Secondary treatment
              includes chlorination prior to discharge to the receiving waters. Receiving waters, also containing high organic
              carbon concentrations, will produce organic chlorine compounds (e.g., chloroform and chloramines), which are
              highly toxic to certain aquatic organisms.
                  Although it does not constitute the greatest volume of water used in refining operations, process water may
              be the most contaminated. The processing pollutants are added during crude-oil desalting, steam distillation,
              steam stripping, etc. Process water discharged from plants is of considerable volume and is highly toxic due
              to its anaerobic and highly reduced character and the presence of numerous heavy metals (primarily three toxic
              metals--mercury, cadmium, and cyanide), sulfides, and ammonia, which are produced together with the oil and
              gas.
                  The NORM deposits may also accumulate in gas-plant equipment, separation facilities, and pipeyards. In
              gas-plant equipment, NORM deposits may accumulate from radon-222 (radon) gas progeny. The gas is
              dissolved in the organic petroleum fractions in the gas plant and partitioned mainly into the propane and
              ethane fractions by its solubility (Rogers & Associates Engineering Corporation, 1990). Components having
              the highest levels of NORM include reflux pumps, propane pumps and tanks, and other pumps and product
              lines. In separation facilities where the separation of water occurs onshore, water handling equipment can
              become contaminated with NORM. Heater treaters, water knockouts, liquid product tanks, separators, tubing
              and piping, water transfer pumps, and other produced-water handling equipment accumulate radium isotopes
              in the form of scale.












                  IV-46


                      The environmental impacts of operational discharges, particularly wastewater effluents, from OCS-related
                  onshore facilities can be both lethal and sublethal. Contaminants could alter localized water quality, decrease
                  photosynthesis of surrounding wetland vegetation, and affect fish resources. Onshore point source discharges
                  will be subject to treatment by municipal and industrial facilities in compliance with Federal and State discharge
                  permit requirements.

                  (c) Air Emissions

                      Onshore air emissions related to OCS activities result from the combustion of fuels, the evaporation and
                  processing of crude oil, and the sweetening of natural gas. Combustion emissions are derived from helicopter
                  and service vessel traffic to OCS facilities. These air emissions from helicopters depend on the number of trips
                  and ripe of helicopters or vessels. Emissions from evaporation result from the transport and offloading of
                  crude oil at terminals and from the fugitive emissions from refining facilities. Offloading air emissions refer
                  to vapor formed over the crude oil in the storage tank and during the offloading. These emissions depend on
                  the ambient temperature, mode of loading into the tanks, physical and chemical characterLstics of the liquid,
                  length of transit, and emission control techniques employed. Fugitive emissions occur from leaks in valves,
                  flanges, pump seals, cooling towers, and oil-water separators.
                      Refining of crude oil is a multiple-step process. Emissions during refining occur in eight of these processes:
                  vacuum distillation, catalytic cracking, thermal cracking, utility boilers, heaters, compressors, blowdown systems,
                  and sulfur recovery. Emissions from gas processing occur only if wastes from the sweetening process are flared.
                  The USEPA publication AP42 (USEPA, 1985), in conjunction with estimates of OCS oil and gas to be
                  processed in these plants, will be employed to estimate the air emissions from these operations. It is important
                  to remember that most of the refining and gas processing facilities have control emission techniques installed,
                  which will reduce the amount of pollutant emitted. The amounts of air emissions from theseactivities is shown
                  in Tables IV-2 and IV-3.


                  (2) Disturbances from New Infrastructure Emplacement

                      New infrastructure emplacements could involve the construction of any of the onshore infrastructure
                  facilities described above in Section IV.A-3.a. The construction of these facilities could result in the conversion
                  of wetlands habitat to dry land as a result of filling operations to prepare the construction site. Construction
                  of facilities on barrier beaches could alter coastal sedimentation and erosion patterns if the site was protected
                  from erosion by armoring of the site.
                     . New pipeline landfalls can result in direct and indirect impacts to coastal wetlands. These impacts have
                  been discussed in Section IV.A.5.(3)(a) of the Final EIS for Sales 139 and 141 and are hearby incorporated
                  by reference. The direct impacts of new pipeline installation projects in wetlands have been reduced in recent
                  years by virtue of new pipeline projects being backfilled after the pipeline is installed. BackI.Ming, by partially
                  filling in the canal cut and levelling spoil banks, reduces the amount of wetland area convened to nonwetland
                  habitat and reduces indirect impacts by reducing saltwater intrusion and removing the drainage interference
                  effects of spoil banks. Turner and Cahoon (1987) have shown a reduction from 2.49 ha/krn of average direct
                  impacts in the past to projected impacts of 0.68 ha/km in the Chenier Plain and 1.05 ha/km in the Deltaic Plain
                  with backfilling.

                  (3) Vessel Usage of Navigatitm Channels

                  (a) Channel Bank Erosion

                      Once dredged, navigation channels can continue to cause impacts to adjacent wetlands by widening of the
                  channel. Johnson and Gosselink (1982) have shown that channels with high navigation usage in coastal
                  Louisiana widen about 1.5 m/yr more rapidly than channels with little usage. The OCS traffic under the Base












                                                                                                                           IV47

               Case scenario is assumed to account for only 0.2 percent of the vessel traffic in coastal channels and a
               proportionate contribution to the overall channel widening problem along the coast.
               (b) Vessel Operational Discharges

                   While spills capture the attention of the general public, operational discharges occurring from vessel
               transportation of oil account for the majority of off discharges. The National Academy of Sciences' report
               (NRC, 1985) estimated that total losses of oil from transportation activities ranged from 7.4 to 19.2 MMbbI
               per year, with a best estimate of 10.7 MMbbI per year. About one-half of this amount is attributed to ballast
               water operational discharges from oil tankers (about 5 MMbbl annually); the remainder is attributed to bilge
               water and fuel oil released from all vessel movement in the ocean (about 2 MMbbl annually), terminal
               operations (about 150,000 bbl annually), dry-docking (about 222,000 bbl annually), and accidental spills (about
               3 MMbbl annually). New regulations, promulgated under the international protocols provided by MARPOL
               73/78 (33 CFR 157), have significantly limited operational discharges (ballast waters) from oil tankers and now
               require onshore receptacles. 33 CFR 157.10B specifically provides even greater restrictions on oil tankers
               carrying OCS produced oil. Because of this, it is assumed that all ballast and bilge waters from the projected
               OCS tanker operations will be discharged into onshore receiving stations.
                   Support vessels servicing the OCS industry offshore are expected to discharge oily bilge waters into the
               water. Volumes of bilge waters discharged from service vessels are expected to result in very low levels of
               open-water contamination. Given the small inputs anticipated, the widespread nature of the receiving waters,
               and the assimilative capacity of water, it is expected that there will only be some localized, short-term changes
               in open-water, chemical characteristics. However, there is a potential for impact when the discharges occur
               in confined waterways.
                   Bilge-water discharges can be calculated from the following equation (NERBC, 1976):

                                                                 Q = 0.004T

                       Where Q = average bilge water generation rate (gals/min) and T = deadweight tonnage (dwt)
                       of vessel.

                   Turner and Cahoon (1987, Vol. III) estimated that 68 percent of the workboats fall into the large category,
               about 55 in (180 ft) in length. Assuming that an average trip within the coastal zone for service vessels is four
               hours and knowing that a 180-ft supply boat weighs 900-1,000 dwt (Caruso, personal comm., 1989), a boat with
               these characteristics would discharge 3,600 liters of bilge waters into navigation channels in the coastal zone.
               Smaller boats (32% of the fleet) would discharge 2,200 liters per trip into coastal waters. Tables IV4 and
               IV-5 provides volumes of bilge waters discharged from service vessels in coastal waters as a result of the Base
               Case and High Case for proposed Sales 142 and 143.
               (c) MaintenancelNew Dredging

                   Dredging must be done periodically to maintain navigation channels at their design depth. Data on the
               frequency of maintenance dredging in channels used by OCS traffic (Table IV-6) are in the process of being
               compiled from U.S. Dept. of the Army Corps of Engineers records and are not available for this Draft EIS.
               This document assumes that the navigation channels listed in Table IV-6 will be maintenance dredged every
               other year during the life of the proposed actions. This document assumes that 0.2 percent of the vessel traffic
               in these channels can be allocated to OCS activities under the Base Case scenario, and 0.4 percent under the
               High Case scenario.
                   In addition to dredging done to maintain channel depths, dredging to deepen existing channels could occur.
               The movement of OCS activities into deeper water areas of the Gulf has created the need for larger and
               deeper draft service vessels. Undercurrent conditions, only Galveston, Texas, and Berwick (near Morgan City),
               Louisiana are considered to have deep enough access channels (5.5-6.7 in) to accommodate the largest vessels











                  IV-48


                  that industry anticipates using mi the future. Venice and Cameron, Louisiana are considered marginal under
                  current conditions. The New Orleans District of the U.S. Army Corps of Engineers has been studying the
                  feasibility of deepening the access channel to Port Fourchon to provide access for deep-draft service vessels
                  (U.S. Dept of the Army, COE, 1991). Based on the distribution of expected deep-water resources in the Gulf,
                  it is assumed that two channels will be deepened to 6.7 m (22 ft): one at Pass Fourchon and one in onshore
                  Subarea W-1 in the Corpus Christi, Texas, area.
                      Maintenance dredging and channel deepening could affect water quality, wetlands, barrier beaches,
                  archaeological resources, and coastal birds and endangered species. The impacts of maintenance dredging and
                  channel deepening will be allocated to the proposed actions according to the 0.2 and 0.4 percent figures given
                  above for the Base and High Case usage of channels.

                  (4) OnshorelCoastal Disposal of Offshore Od and Gas Industry Operational Wastes

                      If OCS drilling and production wastes cannot meet the U.S. Environmental Protection Agency's NPDES
                  effluent limitations or if these limitations require zero offshore discharge, offshore operational wastes must be
                  transported to shore for onshore disposal. If USEPA finalizes its proposed effluent limitatiows, these limitations
                  would greatly increase the amount of both drilling and production wastes brought onshore.
                      In general, offshore wastes not discharged are either piped ashore or loaded on supply boats or barges and
                  transported onshore to industry shorebases. Once onshore they are loaded on trucks or barges to reach a
                  commercial waste disposal facility. Onshore disposal alternatives include landspreading, landspreading with
                  dilution, burial with unrestricted site use, disposal at a licensed commercial oil-field waste site (NOW site),
                  burial in plugged and abandoned wells, well injection, hydraulic fracturing, or injection into salt domes.
                      Regulation of onshore waste disposal is considered beyond the jurisdiction of MMS and rests more with
                  the States. The MMS operating regulations (30 CFR 250.33(b)(9)) do address oil and gas wastes requiring oil
                  and gas operators to identify quantities of wastes generated and disposal approaches in the Exploration Plan
                  documentation. Likewise, documentation submitted in support of Development and Exploration Plans (30 CFR
                  250-34 (b)(8)(c) (iii)) requires disclosure of waste handling and disposal procedures. Furthermore, Section
                  II.B.8.2 of NTL 86-09, "Environmental Report Information Regulations," specifically directs industry to disclose
                  waste handling and disposal procedures. At this time, industry in the Gulf of Mexico only generally addresses
                  their onshore waste disposal plan by stating that State-approved landfill and disposal sites will be used. The
                  MMS conducts a postlease environmental analysis on such exploration and production plans, and these plans
                  are reviewed by the States for consistency determination.
                      Waste disposal is one of the most difficult problems expected to face the United States public in future
                  years. There is considerable concern in the Gulf region about OCS waste onshore disposal practices, primarily
                  because of known past impacts to land use and water quality from these practices.
                      In 1987, USEPA researched onshore oil and gas waste disposal and found considerable environmental
                  damage around disposal sites in the Gulf area from improper regulations and management practices (USEPA,
                  1987; Hall, 1990; Subra, 1990). A USEPA report to Congress summarized these damages: "The principal types
                  of damage sometimes caused by these wastes include contamination of drinking-water aquifers and foods above
                  levels considered safe for consumption, chemical contamination of livestock, reduction of property values,
                  damage to native vegetation, destruction of wetlands, and endangerment of wildlife and impairment of wildlife
                  habitat" (USEPA, 1987). Subra (1990) documented the damage caused by commercial facilities located in
                  Vermilion Parish, Louisiana, and reported that three of these facilities are now on the SuPerfund list. The
                  USEPA is working with the states to improve or implement regulations to control the management of oil and
                  gas wastes (Tonetti, 1990). It is assumed that there will continue to be some future environmental damage
                  near some disposal facilities that will be used by the OCS industry.
                      Besides environmental impact from site contamination, onshore waste disposal can affect land use. In
                  particular, the State of -Louisiana has expressed considerable concern regarding insufficient waste facility
                  capacity to handle future wastes. Furthermore, the State of Louisiana has recently received several requests
                  for landfills to be located in wetland areas. These landfills could receive both commercial (inclusive of OCS
                  wastes) and residential wastes (Demond, personal comm., 1991).











                                                                                                                                    IV49
                     In general, most oil-field operational wastes, such as produced sands and drilling muds, are disposed of in
                the Gulf area at designated ofl-field waste commercial facilities, usually called NOW sites. Off-field waste
                disposal is regulated by the State of Louisiana, who requires that most operational wastes be disposed of at
                NOW facilities permitted by the State of Louisiana. In order to improve our understanding of solid-waste
                disposal, MMS completed an analysis to evaluate the capacity of such solid-waste disposal facilities located
                along the Gulf Coast to handle future onshore waste disposal. Section IV.B.I.c.(3)(c) is an analysis of the
                capacity of NOW sites to handle future generated ofl-field wastes. (The disposal in onshore landfills of
                common trash and debris generated from the OCS off industry is discussed separately below). The MMS
                analysis shows that there is ample capacity to dispose of all future wastes projected to require onshore disposal
                and generated by the total OCS program. Given this, it is assumed that there is sufficient capacity to dispose
                of future waste projected to require onshore disposal and generated by the proposed actions (a subset of the
                total wastes projections).
                     One exception to this analysis is the onshore disposal of NORM-contaminated wastes. One of the most
                pressing regulatory concerns involves finding ways to safely dispose of the rapidly accumulating volume of
                stored NORM-contaminated waste generated during the oil and gas extraction process. Section IV.A2.d.(5)
                discusses the issue of NORM contamination in general and provides known levels of NORM in each waste
                type.
                     The offshore operational wastes of particular concern are production solids and equipment because the
                MMS assumes that all production solids and used equipment will be brought onshore for disposal. Prior to
                1989, production solids disposed of onshore (industry estimates about 20-25% of production solids was
                discharged overboard) were disposed of at commercial oil-field wastes sites. Used equipment was discarded
                or recycled at pipeyards. In 1989, the State of Louisiana, Department of Environmental Quality adopted
                NORM regulations that established strict disposal requirements for all NORM materials emitting radiation
                greater than 50 microREMS per hour. The State of Texas is in the process of developing similar regulations.
                Operators of NOW sites have interpreted these regulations to apply to receipt of ofl-field operational solid
                wastes and are not, in general, accepting any solid material with radioactivity greater than 50 microREMS per
                hour.
                     Rejection by NOW site operators has left very few disposal options available for NORM-contaminated
                materials for the Gulf of Mexico area oil industry. (In this discussion, NORM-contaminated wastes are defined
                as wastes that do not meet the requirements for overboard discharge outlined in the December 11, 1991, LTL
                discussed in Section IV.A2.d.(5) and that are rejected by NOW operators.) At present, the majority of
                operators are storing NORM-contaminated material in approved waste disposal drums and stockpiling the
                material at shorebases until suitable disposal methods are found to avoid future liabilities. There is only one
                waste disposal site in this country that will accept diffuse radium waste; this site is located in Utah.
                Transporting NORM-contaminated materials across State lines is difficult because of regulatory concerns.
                     The MMS has devoted an extensive amount of time and energy examining a number of disposal options
                proposed by industry and, by developing the LTL, is now approving some offshore disposal of production solids.
                Overboard disposal of production solids with low levels of radiation should help mitigate the increasing onshore
                storage problem. It is noted that the preferred option in USEPXs proposed effluent limitation guideline
                regulations, which will supersede the MMS requirements, is zero offshore discharge of produced sands, and
                this is the assumed disposal option analyzed in this document.
                     Proposed disposal options being considered by MMS at this time include encapsulation of contaminated
                tubular goods and solids downhole in wells that are to be "plugged and abandoned"and the downhole disposal
                of NORM-contaminated materials into a depleted reservoir. The second option particularly applies to the
                reinjection of materials currently stored in drums onshore. These materials would be mixed with mud prior
                to transport offshore for reinjection. At present, the State of Louisiana has denied consistency for the onshore
                component of this activity.
                     Both industry and the State of Louisiana are gathering data on the number and location of drums
                containing NORM oil-field wastes and contaminated pipe stockpiles, but no statistics are currently available.
                Solids being stored at shorebases in drums should not be impacting land use or resulting in contamination of
                the surrounding environment if the material is properly stored. This is not the case with existing pipeyards
                projected to be used for future OCS operations. Louisiana has recorded over 600 sites (estimates are up to











                 IV-so
                 2,000 sites) contaminated by previously, improperly disposed of NORM wastes (Zaloudek, Fersonal comm.,
                 1992). Although many of these sites are well operators, sites include many of the pipeyards used by the OCS
                 oil industry. There will be restricted future land-use options for the land now used by such pipeyards.
                      There is also a growing concern among the public that there are an increasing number of incidents of
                 improper disposal of these wastes triggered by the storage problem. For example, incidents of scrap metal
                 being improperly sent to mills lacking radiation monitoring or of solids taken to municipal landfills or dumped
                 in rivers (Raloff, 1991) have been recorded.
                      In conclusion, future onshore disposal of OCS-generated wastes contaminated with 14ORM are not
                 expected to significantly impact land use or environmental resources. Any documented oantamination of
                 existing sites occurred due to historical practices. It is assumed that the OCS industry will properly dispose and
                 store its wastes, whatever the final solution. The MMS reporting requirements listed in the NORM Utter to
                 Lessees should ensure such practices. In general, concerns related to final safe disposal and transport of
                 NORM-contaminated wastes is being addressed on a national level, but answers are not expected to be
                 forthcoming in the very near future.
                      The following discussions provide further information on specific types of OCS offshore operational wastes
                 disposed of onshore.

                 (a) Produced Waters
                      Some of the water produced from oil and gas operations associated with the proposed actions is projected
                 to be piped ashore into Louisiana and then disposed. It is estimated that about 11 percent of produced waters
                 generated as a result of Sale 142 will be brought to Louisiana for disposal in Subarea C-3 (Table IV4;
                 34,071,000 bbl). However, disposal methods to be used are expected to be different from past practices
                 because of recent regulatory changes.
                      Regulatory changes expected or already implemented are based partly on the results of a number of recent
                 studies documenting high localized effects of produced-water discharges in poorly flushed coastal waters and
                 partly on the public's increased awareness of the environmental consequences of produced waters discharged
                 into coastal waters. Both the State of Louisiana and USEPA have new stricter regulations for nearshore or
                 coastal discharges of produced waters. The State of Louisiana promulgated regulations banning the discharge
                 of produced waters in most inland, coastal waters, unless the discharge is in compliance with State effluent
                 limitations. The new regulations became effective in April 1991 with a 4-year compliance schedule for industry
                 (6-year compliance if an operator can show economic hardship). The USEPXs proposed effluent limitations
                 have a preferred option restricting oil and grease content in produced waters to lower quantities in waters
                 within 4 mi from shore (USEPA, 1991), rather than beyond 4 mL It is also expected that USEPA will also
                 develop stricter requirements for produced-water discharges as part of their NPDES for coastal oil and gas
                 production oil and gas operations. The proposed NPDES has not yet been published.
                      Given this regulatory climate, MMS has projected a significant decrease in the volumes of'produced waters
                 currently shipped onshore. However, MMS still assumes that some water will be brought onshore and disposed
                 of by State-approved methods. The MMS's projection of 11 percent onshore disposal is based on the following:
                 (1) it can be more cost effective to collect production from many wells or several fields for separation at a
                 centralized facility-, (2) it is more costly to construct and operate separation facilities on ofthore platforms,
                 especially in deep waters; (3) industry has argued that they cannot meet the USEPA 4-mi stricter limitations
                 and might opt to dispose of their produced waters generated within 4 mi of shore at onshore Louisiana
                 facilities; and (4) a knowledge of the future operating plans for the 15 largest, existing coasuil OCS produced-
                 water separation facilities identified in the Rabalais et al. (1991) study. Presently, these facilides either receive
                 production streams from several pipeline systems serving a number of fields and operators or they are field
                 specific. For instance, the Fourchon terminal currently receives produced waters from 20 blocks. All of these
                 facilities have consulted with the State of Louisiana and are adopting their discharge practices accordingly. Two
                 are shutting down. Two of these sites, the Grand Isle and Sabine Pass separation facilities, will inject future
                 produced waters into wells. The remaining facilities have or are relocating their discharge outfalls to locations












                                                                                                                           IV-51

              that are not prohibited by the State of Louisiana. They will discharge into State open waters, the Mississippi
              River or its passes, or OCS waters.
                  Only the four facilities that receive produced waters from a number of fields and whose management
              indicated that they are upgrading and expanding with the possibility of receiving produced waters from deep-
              water tracts will be considered in the Base and High Case assessments. These facilities, located at Grand Isle,
              Pass Fourchon, near the Mississippi River, and in Sabine Pass, will receive produced waters from future leases
              associated with Sales 142 and 143, and Sale 142 and 143 produced-water coastal disposal will occur by
              reinjection or discharge into the Mississippi River.
                  The projected volume of OCS produced water disposed of onshore was also calculated based on a number
              of assumptions. First, no produced waters associated with gas production will be transported to State waters.
              Second, projected oil platforms located near pipeline systems supporting the four major separation facilities
              have a 50 percent chance of tying into these systems in the future. Third, the separation facilities will continue
              to operate 35 years into the future, disposing of produced waters by the methods recently approved by the
              State of Louisiana.
                  In summary, no surface-water discharge of OCS-generated produced waters into inland coastal waters and
              open bays is projected. Because none of these facilities will be discharging produced waters into State waters
              (with the exception of the Mississippi River), no impacts to coastal environmental resources are expected from
              onshore disposal of produced waters generated as a result of production from proposed Sales 142 and 143.
              (b) Production and Drilling Solids

                   It is projected that 18 percent of drilling muds and cuttings generated from drilling operations associated
              with the proposed actions will be shipped onshore for disposal. This projection is based on the following
              assumptions: (1) oil-based drilling muds will be used when drilling wells beyond 10,000 ft in depth; (2)
              exploration and delineation wells will be drilled to an average of 13,500 ft; (3) all oil-based muds will be
              shipped onshore; and (4) the proposed effluent limitations preferred options will be finalized, i.e., all muds
              generated within 4 mi from shore will be shipped onshore. Total quantities of drilling muds and cuttings
              disposed of onshore are provided in Tables IV-4 and IV-5. It is projected that 100 percent of production solids
              (sands and vessel sludges) will be disposed of onshore. This is based on the fact that USEPA!s proposed
              effluent limitation for produced sands is zero offshore discharge. Section IV.A_2.d.(5)(d) discusses produced
              solids in more detail.
                  No projections of quantities of ofl-field pipe brought onshore are made. After production ceases, oil-field
              pipe has routinely been pulled from the formation and brought to pipeyards to be stacked and reamed out for
              later reuse. Recently passed Louisiana regulations establish guidelines to protect workers at pipeyards.
              Previously, workers employed in the area of cutting and reaming oil-field pipe and equipment may have been
              exposed to health risks associated with inhalation and/or digestion of dust particles containing elevated levels
              of alpha-emitting radionuclides. It is assumed that future pipe may remain in place and will only be recycled
              if all NORM worker safety regulations are met.

              (c) Other Solid Wastes

                  Besides drilling and production wastes, the State of Louisiana has expressed concern for the transport to
              shore of other types of solid wastes, such as mud bags, drums, crates, and a variety of domestic wastes that are
              often disposed of at municipal landfills.
                  No estimate of the volume of trash and debris generated on the OCS is currently available. Such trash
              and debris, when brought onshore for proper disposal at State-approved landfills, may add to the growing
              problem of existing landfill capacity and potential for future expansion. Solid-waste disposal impacts are a
              cumulative issue related to all future OCS Program activities (Section IV.B.3.c.(4)).
                  The MMS has been very active in promoting industry reduction. Our agency issued NTL 86-11, Guidelines
              for Reducing or Eliminating Rash, recommending operators and their contractors and subcontractors develop
              and implement proper trash handling education and training programs. The NTL also recommended reduction











                 IV-52

                 and compaction for all waste materials sent to onshore disposal sites. In May 1990, MMS contacted all lessees
                 and operators and strongly encouraged use of large containers/bulkstorage offshore. Recent evidence available
                 from indo'stry indicates a widespread cooperation with our recommendation.

                 (5) Offshore Coastal Spi&

                     The impact from oil spills associated with the OCS oil leasing program to the environmental resources
                 identified in this document is one of the greatest concerns identified by the public. Although beyond the
                 regulatory authority of MMS, spills can occur from onshore activities supporting the production of OCS oil and
                 gas. Impacts from those spills are analyzed in Section IV.D. These spills are most likely to occur at coastal
                 or onshore storage and processing facilities, particularly at the terminal transfer points and from coastal
                 pipelines and barges moving OCS oil to processing facilities. Because MMS does not maintain records of these
                 spills, the U.S. Coast Guard database on spills was used. This database does not distinguish the source of the
                 spill incident, so projected onshore spill occurrences occurring from proposed action activities are estimates
                 of the likely subset of the larger database. Assumptions of a spill occurring from the Base and High Case
                 scenarios for proposed Sales 142 and 143 are provided in Section IV.C.1.

                 B. CUMULATIVE SCENARIO

                     The CEQ regulations require a cumulative impact analysis to be completed as part of an EIS on a
                 particular proposed action. This analysis analyzes "cumulative" actions, defined as other past, present, and
                 reasonably foreseeable future actions, both Federal and nonfederal (40 CFR 1508.7), that when added with
                 actions resulting from the proposed actions result in an incremental impact to the resources of concern. The
                 time period that these future impacts are examined is limited to the time of the proposed actions (1993-2027),
                 and the resources analyzed are those identified as potentially being impacted from the proposed actions.
                 Cumulative impacts can result from individually minor but collectively significant actions taking place over a
                 period of time.     This cumulative scenario provides characteristics and assumptions about potentially
                 impact-causing events that could result from activities related to the following: future OCS program operations
                 in addition to those resulting from the proposed actions; State oil and gas activities; other major offshore
                 activities such as military operations, sulfur production, and marine transportation; and other major coastal
                 activities such as river modification projects, municipal impacts, and natural subsidence of wetlands.
                     The Gulf of Mexico OCS Region has formulated the following hypothetical scenarios to provide a
                 framework for assessing the additive effects of such future actions with the impacts of the proposed OCS oil
                 and gas lease sales in the CPA and WPA (proposed Sales 142 and 143, respectively).
                 1. Exploration, Development, and Production Scenario and Assumptions
                     for the OCS Leasing Program

                     Tables IV-7 through IV-15 present estimates of the major activities and impact factors related to future
                 OCS Program operations in the Gulf of Mexico. The OCS Program activities are defined as all oil and gas
                 activities occurring in the Gulf of Mexico during the life of the proposals as a result of past, proposed, and
                 future sales on the OCS. Activity that takes place beyond the 35-year timeframe due to future sales is not
                 included in this analysis. Section IV.A-1. provides more information on the criteria considered in the
                 formulation of the resource estimates that have been developed.

                 a. Resource Estimates and Timetables


                     Central Planning Area: Estimates of total resource production related to the proposed. action plus prior
                 and future sales in the planning area (total OCS Program) over the period 1993-2027 are 5.46 BBO and 50.29











                                                                                                                           IV-53
                   Westem Planning Area: Estimates of total resource production related to the proposed action plus prior
               and future sales in the planning area (total OCS Program) over the period 1993-2027 are 1.21 BBO and 22.50
               tcf of gas (Table IV-1). It is projected that during this period approximately 70 percent of the total oil and
               gas resources and reserves available in the WPA at the time of the proposed action will be produced.
                   Eastem Planning Area: Estimates of total resource production related to prior and future sales in the
               planning area (total OCS Program) over the period 1993-2027 are 0.19 BBO and 1.05 tcf of gas. It is projected
               that during this period approximately 20 percent of the total off and 60 percent of the total gas resources and
               reserves available in the EPA in 1993 are produced.
               b. Description of Offshore Operations and Impacting Factors

                   Existing offshore infrastructure related to the oil and gas industry is highly concentrated in the CPA and
               WPA. To date, only OCS exploration activities have taken place in the Eastern Gulf of Mexico. Tables IV-7,
               IV-8, and IV-9 provide estimates of existing offshore structures, actual 1990 installations, and projected
               installations for the CPA, WPA, and EPA.
                   Tables IV-7 through IV-1 1 show the magnitudes of projected offshore infrastructure and the impact factors
               or agents that are projected to occur in the various offshore subareas of the CPA and WPA from the ftiture
               OCS Program activities during the 35-year life of the proposed actions. In addition, these tables provide a
               breakdown of these impact-producing factors by offshore subarea. Note that even though some offshore
               subareas do not have development activity indicated, they would have potential for development under a more
               favorable economic climate. Because of this fact, one can reasonably assume that exploration could take place
               in these subareas.

               (1) Offihore Inftastrwture and Activities

               (a) SurveyinglSeismic Operations

                   In addition to postlease seismic surveys that result only from the proposed actions, prelease seismic surveys
               from on-going OCS activity may be conducted on a speculative basis. (For further discussion of seismic
               operations, see Section IV.A-2.a.) Prelease operations are conducted by major seismic companies to survey
               unleased areas or to resurvey leased areas using new technology. Prelease speculative surveys and resurveys
               are conducted to locate and/or examine areas of hydrocarbon potential. The resulting information is offered
               for sale to the Gulf of Mexico oil and gas industry and is made available on a confidential basis to MMS, Office
               of Resource Evaluation. All prelease surveys, resurveys, or speculative surveys done on postlease areas are
               reviewed and permitted by MMS, Office of Resource Evaluation.                    In 1990, 155 (226,334 km)
               prelease/speculative seismic surveys were permitted in the CPA and 63 (78,367 km) were permitted in the WPA
               (Brinkman, personal comm., 1991). From January 1 through September, 1991, 78 (168,947 km) of these
               surveys were permitted in the CPA and 32 (37,470 km) were permitted in the WPA (Brinkman, personal
               comm., 1991). It is assumed that all seismic operations will be nonexplosive and that there will be a maximum
               of 150 prelease seismic surveys per year in the CPA and 50 per year in the WPA as a result of all future OCS
               activity. However, the rates assumed are based on 1990 data; one year's data collection. It is expected that
               prelease surveys will decline at an unknown rate for the next 35 years, in parallel with declining oil and gas
               development
               (b) Drilling Rigs and Platfomu

                   Section IV.A.2.a.(2) provides general information regarding assumptions and descriptions about the three
               phases of activity required to produce oil and gas resources: exploration and delineation, development, and
               production. To discover and develop resources in the CPA will require the drilling of 5,890 exploration and
               delineation wells, the emplacement of 340 new platform complexes, the use of 3,422 existing platforms, and
               the drilling of 5,130 oil and gas development wells (Table IV-7); to discover and develop resources in the WPA














                                                                                                        Table IV-7

                                                  offshore Scenario Information Associated With OCS Program Activities in the Central Planning Area
                                                                                               for the Years 1993-2027

                                                                                                                           Offshore Subarea*
                                                                          ----------------------------------------------------------------------------------------------------
                                                                           Total*                  C-1                  C-2                C-3               C-4               Total CPA
                                                                            to      1990       OCS Program        OCS Program          OCS Program       OCS Program           OCS Program
                                                                           Date Annual         Activities         Activities           Activities        Activities            Activities
                                                                          --------------       ------------       ------------         -----------       -----------           -----------
                    offshore (Total      Peak Year**)
                    --------------  7 ---------------

                    Wells Drilled:
                      Exploration and Delineation Wells                  7,430  /   308         750        51     1,695    115         1,970    134      1,475         100    5,890   /      400
                      Development Wells---                              17,163  /   420         785        36     1,565       72       1,790       82     990          45     5,130   /      235
                       Oil Wells                                         9,397  /   188         470        21      925        42       1,165       53     530          24     3,090   /      140
                       Gas Wells                                         7,766  /   232         315        15      640        30        625        29     460          21     2,040   /      95
                    Platform Complex Installations
                      Number Installed                                   3,422  /   57           52        3        98        6         117        8         73        5        340   /      22
                    Space Use Loss (ha during 35 yrs)                       NA  / NA        164,700     /8,520    85,068 /4,158        51,270 /2,448         0         0     301,038  /15,126
                    Structure Removals    Using Explosives                  NA  / NA            936        48      538        27        435        21        2         1      1,887          94
                    Method of oil Transportation
                         Percent Piped                                      NA  / NA             NA     NA          NA     NA            NA     NA           NA  NA               97%/ 97%
                         Percent Barged                                     NA  / NA             NA     NA          NA     NA            NA     NA           NA  NA                 3%/      3%
                         Percent Tankered                                   NA  / NA             NA     NA          NA     NA            NA     NA           NA  NA               <1%/ <1%
                    Shuttle Tanker Traffic (trips)                            0 /     0            0       0          0       0          41        2         4         1          45         2
                    Barge Traffic (trips)                                   NA  / NA           3,109    136        228        10       3,488    153          0         0      6,828          299
                    Pipeline Length (km)                                28,595  /1,215          530        31     1,395       84       2,125    128      1,005         62     5,055          300
                    Pipeline Displaced Sediments (1,000 m')                 NA    NA           2,200    127       2,523    154         2,409    161          0         0      8,384          538
                    Bottom Area Disturbances (ha)
                      from rig emplacements                                 NA    NA           1,125       77     1,919    130         1,849    126       310          21     6,165          419
                      from structure emplacements                           NA    NA            104        6       148        9         145        9         20        1        472          29
                      from pipeline projects                                NA    NA            170        10      446        27        680        41     322          20     1,618          96
                    Accidents
                      offshore Oil Spills
                         >1 and <50 bbl                                     NA    NA           .... NA  /NA         NA     NA            NA     NA           NA  NA             830    NA
                         >50 and <1,000 bbl                                 NA    NA             NA     /NA         NA     NA            NA     NA           NA  NA               33   NA
                         >1,000 bbl                                         18    NA             NA     /NA         NA     NA            NA     NA           NA  NA                 7  NA
                      Blowouts                                              NA    NA             24     /  1        36        2          40        2         30        2        130          7
                      Diesel and other    Pollutant Spills                  NA    NA             93     /  4       119        5         143        6         44        2        399          17
                    Support Activities
                      Helicopter Trips      (1,000's)                       NA    NA           13,288   /687      9,772 /  480         9,754    469      1,255         60     34,069   1,652
                      Service Vessel Trips (1,000's)                        NA    NA            224     /  12      203  /     11        212        11        63        4        701          36
                    offshore operational Wastes
                      Drilling Fluids (1,000 bbl)                           NA    NA           10,648   /607      22,654 /1,306        26,135 /1,509     17,204  1,017        76,642   4,440
                      Drill Cuttings (1,000 bbl)                            NA    NA           2,512    /146      5,379 / 316          6,210 / 366       4,149         250    18,250   1,077
                      Sanitary Wastes    (1,000 M3)                         NA    NA           28,481   /1,480    31,494 /1,557        34,059 /1,650     8,386         399  102,343    5,054
                      Produced Waters (KMbbl)                               NA  / NA           2,304    /NA       3,673 /  NA          4,448 /  NA       1,833   NA           12,258   NA
                      Produced sands (1,000 bbl)                            NA  / NA            637     /  28      815  /     36        977  /     43     302          13     2,731          120
                    offshore Air Emissions (1,000 tons)
                      Nitrogen oxides                                       NA  / NA           888.43   /NA       589.37/  NA          533.52/  NA       45.38   NA         2,056.70   NA
                      carbon monoxide                                       NA  / NA           54.52    /NA       36.17 /  NA          32.74 /  NA       2.78    NA           126.21   NA
                      Sulfur Oxides                                         NA  / NA           9.87     /NA       6.55  /  NA          5.93  /  NA       0.50    NA           22.85    NA
                      ToLal Hydivearbon Compounds                           NA  / NA           52.20    /NA       34.63    NA          31.35 /  .1.1 A   2.67    NIA          120.84   NA
                      Total Suspended Particulates                          NA  / NA           5.82     /NA       3.86     NA          3.50  /  NA       0.30    NA           134.75   NA


                          As shown in Figure IV-1.
                          Not all development wells     classified as oil or gas      produce.
                          The peak year numbers for     the individual subareas may not sum to the peak year number for the total planning area because all peak
                          years may not occur simultaneously.
                          Data cannot be revealed by subarea because proprietary information could be exposed.















                                                                                                       Table IV-8

                                       offshore Scenario Information Associated With OCS Program Activities in the Western Planning Area for the Years 1993-2027

                                                                                                                     Offshore Subarea*
                                                                                ---------------------------------------------------------------------------------
                                                                                Total                  W-1                 W-2              W-3            Total WPA
                                                                                 to      1990      OCS Program       OCS Program        OCS Program       OCS Program
                                                                                 Date Annual       Activities        Activities         Activities         Activities
                            Offshore (Total / Peak Year**)                      -----  -------     ------------    ------------         -----------        ------------
                            ----------------------------

                            Wells Drilled
                              Exploration and Delineation wells               1,924 /    187        340  /   25    1,550   /  113      3,390  /  247     5,280       385
                              Development Wells-**                            1,949 /    62         145  /     7     655   /  32       1,250  /     61   2,050       100
                               Oil Wells                                         28S      2            20      0     290      13         560        26     870       40
                               Gas Wells                                      1,664      60         125        6     365      19         690        35   1,180       60
                            Platform Complex Installations
                              Number Installed                                   380      6            15      1       40       3           85      7      140       11
                            Space Use Lose (ha during 35 years)                  NA    N&          21,252 /1,056   12,738     546           0       0    33,990  1,602
                            Structure Removals   Using Explosives                NA    NA           116  /     6     109        5           6       1      231       12
                            Method of Oil Transportation
                                Percent Piped                                    NA    Nk          ****NA/ NA          NA  /  NA            NA/  NA         set/     88%
                                Percent Barged                                   NA    NA              NA/ Nk          Nk  /  NA            NA/  NA           it/      it
                                Percent Tankered                                 NA    NA              NA  NA          NA     NA            NA   NA         lit/     lit
                            Shuttle Tanker Traffic (trips)                         0      0            0       0        0       0        960        33     960  /    33
                            Barge Traffic (trips)                                NA    Nk           531      18      228        8           0       0      759  /    26
                            Pipeline Length (km)                              4,654      195        790      71      860      73       1,860     162     3,510  /    305
                            Pipeline Displaced Sediments (1,000 ml)              NA    NA           701      40      614      42            0       0    1,290       90
                            Bottom Area Disturbances (he)
                              from rig emplacements                              NA    Nk           510      38    2,103      153        908        66   4,176       304
                              from platform emplacements                         NA    NA              301     2       72       5           29      3      142       12
                              from pipeline projects                             NA    Nk           253      23      275      23         595        52   1,123       98
                            Accidents:
                              offshore Oil Spills
                                 1 and <50 bbl                                   NA    Nk          ****NA  NA          NA     NA            NA   Nk        183   Nk
                                >50 and <1,000 bbl                               NA    NA              Nk  NA          NA     Nk            NA   NA           7  NA
                                >1,000 bbl                                       Nk    NA              Nk  NA          NA     NA            Nk   NA           2  NA
                              Blowouts                                           NA    NA              11      1       23       2           40      3       74         6
                              Diesel and Other  Pollutant Spills                 Nk    NA              5       1       37       1           46      2       88         4
                            Support Activities
                              Helicopter Trips    (1,000's)                      NA    NA          1,737     86    1,962      84       1,035        51   4,734       174
                              service Vessel Trips (1,000's)                     Nk    NA              35      2       71       4           93      6      211       12
                            Offshore Discharges
                              Drilling Fluids (1,000 bbl)                        NA    NA          3,404   226     15,478  /1,022      28,605 /1,978     51,503  3,421
                              Drill Cuttings (1,000 bbl)                         NA    Nk           837      56    3,809      255      7,218     503     12,715      856
                              Sanitary Wastes (1,000 m3)                         NA    NA          4,568   232     5,428      259      3,829     233     19,714      870
                              Produced Waters (MMbbl)                            Nk    NA           108  / NA        842      NA       1,548     NA      2,458   Nk
                              Produced Sands (1,000 bbl)                         NA    NA              34/     1     251        9        317        11     602       20
                            Offshore Air Emissions (1,000 tons)
                              Nitrogen oxide                                     NA    Nk          146.43/ NA      142.77     NA       65.89     Nk      355.10  NK
                              Carbon Monoxide                                    NA    NA          24.35   NA      23.74      NA       10.96     NA      59.04   NA
                              Sulfur oxide                                       NA    NA          5.09    NA        4.96     NA        2.29     NA      12.33   NA
                              Total Hydrocarbon Compounds                        NA    NA          39.25   NA      17.66      NA       17.66     NA      95.19   NA
                              Total Suspended Particulates                       NA    Nk          5.56    NA        5.42     Nk        2.50     NA      13.48   NA


                                 As shown in Figure IV-1.
                                 Not all development wells    classified as oil or gas    produce.
                                 The peak year numbers for    the individual subareas may not sum to the peak year number for the total planning area because all peak
                                 years may not occur simultaneously.
                                 Data cannot be revealed by subarea because proprietary information could be exposed.
































                                                                                                              Table IV-9

                                                 offshore scenario information Associated With OCS Program Activities in the Eastern Planning Area for the Years 1993 -2027

                                                                                                                              Offshore Subarea*
                                                                            ---------------------------------------------------------------------------------------------------------------------
                                                                             Total                 E-1                 E-2              E-3              E-4                  E-5           Total EPA
                                                                              to    1990      OCS Program       OCS Program         OCS Program      OCS Program          OCS Program       OCS Program
                                                                             Date Annual        Activities       Activities          Activities       Activities           Activities       Activities
                                                                            --------------     ------------     ------------         -----------      -----------          -----------      -----------
                          Offshore (Total    Peak Year**)
                          ----------------------------

                          Wells Drilled
                            Exploration and Delineation Well*                 44  /    0         270 /     is      25  /    2           0 /    0         0 /      0        245        16      540        35
                            Development Well****                                0 /    0         90  /     7       10  /    1           0 /    0         0 /      0        150        12      250        20
                             Oil Wells                                          0      0         is  /     1       10       1           0 /    0         0 /      0        130        10      155        12
                             Gas Wells                                          0      0         75        6         0      0           0 /    0         0 /      0         20        3       95         8
                          Platform Complex Installations
                            Number installed                                    0      0         14        1         4      1           0 /    0         0 /      0         12        1       30         3
                          Method of oil Transportation
                              Percent Piped                               -*NA    /Nk            Nk      Nk        Nk  /  NA           NA /  NA         NA     Nk           IRA    Nk         NA      NA
                              Percent Barged                                  NA  /NA            Nk      NA        NA  /  NA           NA /  NA         NA     NA           Nk     Nk         NA      Nk
                              Percent Tankered                                NA   Nk            Nk      Nk        NA  /  NA           NA /  NA         NA     NA           NA     NA         NA      NA
                          Pipeline Length (km)                                  0      0         920       90      80  /    9           0 /    0         0        0        175        21    1,175        115


                               An shown in Figure IV-1.
                               The peak year numbers for the individual subareas may not sum to the peak year number for the total planning area because all peak
                               years may not occur simultaneously.
                               Not all development wells classified as oil or gas produce.
                               Data cannot be revealed by subarea because proprietary information could be exposed.











                                                                                                                            IV-57

               will require the drilling of 5,280 exploration and delineation wells, the emplacement of 140 new platform
               complexes, the use of 380 existing platforms, and the drilling of 2,050 off and gas development wells (Table IV-
               8); and, to discover and develop resources in the EPA will require the drilling of 540 exploration and
               delineation wells, the emplacement of 30 platform complexes, and the drilling of 250 oil and gas development
               wells (Table IV-9).

               (c) Shucture Removals

                    In addition to postlease structure removals that result only from the proposed action and due to the fact
               that lessees are required to remove all structures and underwater obstructions from their Federal OCS leases
               within one year of the lease's relinquishment or termination of production, structure removals occur from on-
               going OCS activity. (For further discussion of structure removals, see Section IV.A_2.(a).(3).)
                    The MMS has issued strict guidelines to offshore operators for explosive platform removal in order to
               eliminate potential harm to endangered marine turtles and marine mammals. These guidelines include daylight
               detonation only, staggered charges, placement of charges 5 m below the seafloor, and pre- and postdetonation
               surveys of surrounding waters. It is assumed that these guidelines will be followed during the removal of all
               OCS platforms. It is assumed that 80 percent will be removed by explosives in water depths less than 455 m.
               In water depths greater than 455 m engineering differs due to the requirements of deep-water technologies.
               Each year it is estimated that 4.1 percent of the remaining OCS structures will be removed as a result of an
               OCS activity. The rate of removal will average 75 structures per year in the CPA (annual range of 40-131) and
               10 in the WPA (annual average of 9-14). In the CPA, there will be 1,897 structures removed explosively (94
               in the peak year); in the WPA, in there will be 231 structures removed explosively (12 in the peak year).

               (d) WorkoverlAbandonment Activities

                    Workover operations consist of work conducted on wells after the initial completion for the purpose of
               maintaining or restoring the productivity of a well. Tubing can be pulled and the casing at the bottom of the
               well pumped and washed free of sand that may have accumulated. Other examples of workover operations
               are acidizing of the perforated interval in the casing, plugging back, squeezing cement, mining out cement,
               jetting the well in with coiled tubing and nitrogen, setting positive plugs to isolate hydrocarbon zones, etc.
               Workover operations can require the use of a jack-up barge. Operations, which can take from a few days to
               several months to complete, occur in mature oil and gas areas and, thus, are common in the Gulf of Mexico.
               In 1990, about 4,200 completions, workovers, and plugging/abandonmentoperations occurred, with about 2,400
               of these requiring rig emplacement In general, about 20 percent of all workover operations include rig
               emplacement. All plugging/abandonmentoperations performed when the well has finished production require
               rig activity. Worldwide rig activities show that workover rig activities accounted for 15 percent of rig drilling
               operations from 1986 through 1990 (The Offshore International Newsletter, 1991).
                    Given such levels of activity, it is expected that workover activity will remain an important component of
               future OCS Program operations. However, as total offshore activity decreases so will workovers. The following
               are assumptions about workover activities used to develop estimates of future activities: Given that most wells
               require from one to three workovers during their lifetime, it is assumed that new development wells will require
               1.5 workover operations during their lifetime plus one plugging/abandonment operation. Realizing that there
               is no knowledge of the status of workover operations on existing wells, it is assumed that each existing well will
               require one-half the number of workovers than expected for new wells, i.e., 0.75 workovers per existing well
               plus one plugging and abandonment operation. Using these assumptions, estimates of workover operations
               for all future OCS Program operations are 12,653 workover operations in the CPA, plus 11,740
               plugging/abandonment operations and 4,958 workovers in the WPA, plus 3,254 plugging/abandonment
               operations. No peak-year activity is available. Operations will average 10 days and will require support
               services similar to support provided during the development of the well. Twenty percent of workover
               operations are assumed to require rig emplacements.











                  IV-58

                  (2) Offshore Transport of Oil and Gas

                      Transportation of petroleum hydrocarbons to onshore terminal facilities in the Central Lnd Western Gulf
                  of Mexico historically has relied on an ever-expanding pipeline network. Along with the movement of oil and
                  gas/condensate through pipelines, a small percentage of oil has traditionally been barged from shallow water
                  areas to onshore oil terminals. Because MMS projects that leasing in deep-water blocks not located in
                  proximity to the existing oil-pipeline network will occur as a result of the proposed actions and because of the
                  lack of a onshore infrastructure in Florida, future shuttle tanker transport of oil is projected to occur in all
                  three planning areas. Section IV.A.2.b. describes general information, assumptions, and potential impacts
                  concerning the three modes of oil and gas transport occurring in association with OCS oil and gas leasing:
                  pipelines, barging, and shuttle tanker operations. Tables IV-7 through IV-9 present projected percentages of
                  oil transported via each mode expected for all future OCS Program activities (1993-2027). Nearly an
                  economically recovered natural gas is assumed to be piped to shore. Tables IV-10 and IV-11 provide
                  information about projected kilometers of new trunklines. Tables IV-12 through IV-14 provide information
                  on the volumes of oil making landfall in the various onshore subareas from offshore barging, tanker transport,
                  or piping operations, and on the locations of offloading operations, including transport from the Eastern Gulf.
                  Table IV-15 provides information on the waterway usage by the number of barge and shuttle tanker trips and
                  the terminals where the offloading is expected to occur. Section IV.B.1.c. discusses the locations of the
                  offloading terminals and/or major ports projected to serve oil tanker and barge operations associated with
                  future OCS Program activities.
                      Historically, about 3 percent of the oil produced in the Gulf of Mexico has been barged to shore. It is
                  expected that the general level of barging activity will remain the same in the future and that this activity will
                  remain in water depths less than 3,000 ft. Projected percentages of oil to be barged during future OCS
                  Program activities are 3 percent in the CPA and a little more than 1 percent in the WPA. In the CPA, over
                  6800 barge trips are estimated to occur from future Central Planning Area OCS Program a0vities (Table IV-
                  7). Most of the barging activity in the CPA will originate from Subareas C-1 and C-3. In the WPA, only 759
                  barge trips are expected to occur from OCS Program activities occurring during the 35-year life of the proposed
                  action. Most of these trips will originate in Subarea W-1, with the remaining occurring from Subarea W-2
                  (Table IV-8).
                      Although shuttle tanker transport of OCS Gulf of Mexico oil has not occurred to date, it is expected that
                  shuttle tanker transport of OCS oil will occur from future leases located in deep waters outside of the existing
                  pipeline network in support of the OCS Program. Less than one percent of oil produced in the CPA as a
                  result of OCS Program operations, occurring during the 35-year life of the proposed actions, is estimated to
                  be transported via 45 shuttle tanker trips (Table IV-7). These trips will originate primarily in offshore Subarea
                  C-3 and will offload at the Mississippi River ports (Tables IV-7 and IV-15). Under the High Case, five trips
                  are expected (Table IV-2).
                      Eleven percent of the oil to be produced in the WPA as a result of OCS Program activities (1993-2027)
                  is estimated to be transported to shore by shuttle tankers (Table IV-8). Sixty-six trips are expected, all
                  originating in Subarea W-3 and offloading at five major port areas in both Texas and Louisiana (Tables IV-13
                  and IV-15).
                      Because no pipeline system exists in the Eastern Gulf and because of the lack of an onshore infrastructure
                  base to store and refine oil produced in the EPA from OCS Program operations, almost 94 percent of the oil
                  projected to be produced in the EPA will be transported by shuttle tankers to CPA onshore support facilities
                  (Table IV-9). Five hundred and thirty trips of 50,000-dwt shuttle tankers are expected to transport oil
                  produced in the EPA to terminals along the Mississippi River, in Pascagoula, Mississippi, and in Mobile,
                  Alabama. Table IV-15 shows the number of trips to each of these three offloading areas and the coastal
                  waterways traversed.
                      Most of the oil and gas resources discovered in the Gulf of Mexico will be piped ashore, relying on the
                  extensive and continually expanding existing pipeline network. As of October 1990, approximately 33,249 km
                  of OCS pipelines had been constructed in the Central and Western Gulf of Mexico, whereas no pipeline
                  construction had occurred in the Eastern Gulf. The M'stallation of new pipelines on the OCS will be needed











                                                                                                                              IV-59

             to bring undeveloped resources ashore and to connect new production platforms to existing pipeline systems.
             Under the OCS Program scenario, 97 percent of the liquid hydrocarbons in the CPA and 88 percent in the
             WPA are projected to be transported by pipeline. To date, all natural gas developed on the OCS has been
             transported to shore via pipeline. Under the proposed action, it is assumed that nearly all economically
             recoverable natural gas will continue to be piped to shore, but that a small percentage (less than 1%)
             developed in deep-water tracts that are not located near an existing pipeline network will be handled
             differently. Options include flaring (which is currently prohibited by MMS) or converted to other products--
             such as methane, fiquified gas, or water--prior to transportation by tanker. The MMS is currently working with
             OCS operators to develop methods to transport natural gas resources in areas where transportation by pipeline
             is not economically feasible.
                  In the Central Gulf, there were an estimated 28,595 kni of pipelines (trunk and gathering lines) as of 1990.
             Another 2,N9 kni of new trunklines (1,080 km--oil, 1,224 km--gas) and 2,751 kni of new gathering lines win
             be constructed to support current and future oil and gas activities in the CPA (Table IV-10). Sixty-eight
             percent of aft new trunklines will be constructed in water depths greater than 300 m. Peak-year pipeline
             construction projections are projected to be 300 km. Seventy-one percent of all new pipeline construction in
             the CPA will occur in offshore Subareas C-2 (1,305 km) and C-4 (1,980 km). Three new pipelines are
             projected to make landfall along the Mississippi and Alabama coasts in Jackson County, Mississippi (1--oil),
             and Mobile County, Alabama (2--gas). Of these, the new oil pipeline in Jackson County and a new gas pipeline
             in Mobile County will be constructed to support OCS activities adjacent to the northwest Florida panhandle
             coastal area, as well as activities in the CPA east of the Mississippi River.

                                                                 Table IV-10


                                                      Projected New Central Gulf OCS
                                               Oil and Gas Trunklines (km) by Water Depth

                   Offshore              0-1,000'            1,000'-3,000'           3,000' +               Total
                   Subareas             Oil   Gas            Oil     Gas             Oil  Gas            Oil    Gas

                      C-1             120        0              0       0              0       0          120         0
                      C-2             160       64           144       96             40      96          344      256
                      C-3             200      216           136       48            160    416           496      680
                      C4                 0       0              0       0            120    288           120      288

                      Totals          480      280           280      144           320     800           1,080   1,224
                  In the Western Gulf, there were an estimated 4,654 kni of pipelines as of 1990. Another 2,368 kni of new
             trunklines (992 km--off; 1,376 km--gas) and 1,142 km of new gathering lines will be constructed to support
             current and future oil and gas activities offshore Louisiana and Texas. Table IV-11 estimates the total length
             of new trunklines projected for the WPA_ Sixty-seven percent of the projected new trunklines will be
             constructed in water depths greater than 300 m. Peak-year pipeline construction projections equal 305 km.
             Fifty percent of all new pipeline construction will occur in offshore Subarea W-3 (1,176 km). Three new oil
             pipelines are projected to make landfall along the Texas coast in Matagorda County (Matagorda Peninsula),
             Calhoun County (Matagorda Island), and Nueces County (Mustang Island).











                   IV-60


                                                                       Table IV-11


                                                           Projected New Western Gulf OCS
                                                    Oil and Gas Trunklines (km) by Water Depth

                        Offshore              0-1,000'            1,000'-3,000'           3,0001 +                Total
                        Subareas             Oil    Gas           Oil      Gas           Oil      Gas          Oil    Gas

                           W-1              280     224               0    128               0     32           280      384
                           W-2               120     128             88    192               0       0          208      320
                           W-3                 0       0            120      64           384     608           504      672

                           Totals           400     352            208     384            384     640           992     1,376

                       In the Eastern Gulf, approximately 690 kin of new trunklines (290 km--oil, 400 km--gaLs) and 450 kin of
                   new gathering lines will be constructed to support current and future oil and gas activities offshore Florida.
                   No pipelines are projected to make landfall along the Florida coast; however, two new pipelines (one oil and
                   one gas) will be constructed to support current and future activities off Florida's northwest coast, as wen as
                   activities in the CPA east of the Mississippi River. It is anticipated that these pipelines will make landfall in
                   Jackson County, Mississippi, and Mobile County, Alabama.
                       With the increasing trend toward leasing and development in deep-water areas of the Gulf, pipeline
                   installation projects are extending into water depths that will require new technological innovations. This
                   document assumes that technological advances during the life of the proposed actions will allow pipeline
                   installations in water depths exceeding 1,525 in (5,000 ft). Deep-water pipeline installation challenges include
                   the design of flow systems that can withstand the high external hydrostatic pressures at the seafloor, the
                   adaption of existing lay-vessel and mooring technology to deep-water conditions, and tie-in, roblems at deep-
                                                                                                                     P
                   water production structures.
                       One approach to deep-water installation projects has been to assemble long lengths (up to 10 kin or 6 mi)
                   of pipe onshore and to tow the assembled pipe to the production site. This approach hasalready been used
                   successfully for a project in the Green Canyon Area, and is being planned for a new pipeline project in the
                   Mississippi Canyon Area. Section IV.A-2.b.l. contains a discussion of pipe towing and the assumptions this
                   document uses to evaluate the impacts of this pipeline installation method on the potentially affected resources
                   of the Gulf. Under the OCS Program, it is assumed that some deep water trunk line and gathering line
                   projects will use pipe towing from shore-based facilities.

                   (3) Offshore Transport of PersonnellSapplies

                       It is expected that personnel and supplies will continue to be transported to offshore drilling and
                   production sites by both service vessels and helicopters. Tables IV-7 and IV-8 provide the number of trips
                   occurring offshore from each of these modes of transport for each subarea in the Central and Western Gulf
                   of Mexico. Section IV.A.2.c. discusses offshore support operations in general, describing the activities and their
                   expected impacts. Service bases, heliports, and vessel usage of coastal areas are discussed in Section IV.B.l.c.
                       There are 701,000 service vessel trips projected to occur in the CPA (Table IV-7) and 211,000 trips in the
                   WPA (Table IV-8) from future OCS Program operations occurring during the 35-year life of the proposed
                   actions, with 36,000 and 12,000 trips occurring during the peak year, respectively. Because of the increase in
                   OCS activity in deep waters far from shore support, service vessels are expected to be larger and deeper draft
                   than existing vessels. Future changes in service bases and coastal transport occurring in association with the
                   use of deeper draft vessels are discussed in Sections IV.B.l.c.(l) and 1(b).
                       A large amount of helicopter traffic is projected to occur to support all future oil and gas operations
                   occurring during the 35-year life of the proposed actions. Over 34 million helicopter trips in the CPA and
                   almost 5 million trips in the WPA are expected to occur (Tables IV-7 and IV-8).











                                                                                                                               IV-61
                    There are approximately 600 aircraft servicing the oil and gas industry's transportation needs in the Gulf.
                Since 1985 the number of aircraft in the fleet has declined by about 150 helicopters. Three or four oil and gas
                operators own and operate helicopters; however, most helicopters used in the oil and gas fields of the Gulf of
                Mexico are leased from 11 commercial helicopter operators. Historically, helicopter operations accounted for
                approximately 2 million flights annually (takeoffs and landings), representing over 0.5 million flight hours
                transporting 3.5 million passengers a year. Based on the MMS projections of total trips during 1993 to 2027,
                helicopter trips will decline to average about 1 million flights annually, half as much as the above figure for
                1989.
                    As of 1991, about 400 shore-based helicopters fly every day, with another 75 helicopters based offshore.
                At any one time, 15-20 percent of the fleet of 600 aircraft is in maintenance and not operational. The average
                length of helicopter trips/flights involved in OCS operations in the CPA and WPA is 15 minutes. Historically,
                helicopters are in the air 3.5 hours per day and make about 13 or 14 trips.
                    In support of all future OCS operations, it is assumed that, although the number of trips are expected to
                decrease as the fleet flies farther offshore, the total flying time will remain at historical levels. Therefore, for
                analytical purposes, future flying times per helicopter are estimated to be between 3 and 4 hours daily, but each
                flight will take longer, averaging between 30 and 40 minutes. Furthermore, the number of trips daffy per
                drilling, pipelaying, or production operations are expected to be the same as projected under the Base Case
                scenario (Section IV.A-2.c(2)).
                    Between Mobile, Alabama, and Brownsville, Texas, there are 33 helicopter hubs and 325 heliports (1-46
                helipads per heliport) actively supporting offshore off and gas operations. Offshore, approximately 2,000
                platforms, 200 drilling rigs, and 8 barges involved in oil and gas operations have heliport facilities. In 1989 the
                accident rate was one accident per 200,000 takeoffs and landings. (Current and historical information derived
                from Helicopter Safety Advisory Conference, 1991; Osborne, personal comm., 1991).
                (4) Offshore Impacting Factors Related to Future OCS Operations

                (a) Bottom Disturbance

                    A detailed description of the disruption of the seafloor by the placement of structures (including rigs,
                platforms, and pipelines) and anchors from oil and gas operations is given in Section IV.A-2.d.(l) above and
                is not repeated here. As noted therein, such disruption may impact sensitive biological and archaeological
                resources if no mitigation measures are imposed. Various NTL's exist and stipulations are proposed to protect
                archaeological and sensitive biological resources from damage during these activities. As noted, jack-up rigs
                and semisubmersible rigs, used in water depths less than 457 in (1,500 ft), disturb a total of approximately 1.5
                ha (3.7 ac). It is assumed that 2 ha (4.9 ac) of the bottom will be directly affected by the installation of
                production platforms; in deeper waters, the area affected doubles to 4 ha (9.9 ac). (These rig and platform
                numbers include disturbance by anchors used during installation.) Pipelines disturb about 0.32 ha (0.8 ac) for
                each kilometer (0.62 mi) of pipeline installed.
                    The development scenario for the OCS Program for proposed Sale 142 assumes 5,890 exploration and
                delineationwells and 340 platform complexes (Table IV-7). This equals the direct disturbance of approximately
                6,637 ha (16,400 ac) of open-ocean bottom. It is estimated that 5,055 kin (3,140 mi) of pipelines will be
                installed, resulting in the disturbance of another 1,618 ha (3,998 ac) of bottom. The trenching (burying) of
                pipelines (only in water depths less than 61 in (200 ft)) resuspends some 5,000   M3  (6,540 yd) of sediments per
                kilometer (0.62 mi); under this scenario, 8,384,000 M3  (10,966,272 yd) of sediments would be resuspended into
                the water column over the 35 years of activity.
                    The development scenario for the OCS Program for proposed Sale 143 assumes 5,280 exploration and
                delineation wells and 140 platform complexes (Table IV-8). This equals the direct disturbance of approximately
                4,318 ha (10,670 ac) of open-ocean bottom. It is estimated that 3,510 kin (2,180 mi) of pipelines will be
                installed, resulting in the disturbance of another 1,123 ha (2,775 ac) of bottom, and 1,290,000 M3 (1,687,320
                yd) of sediments would be resuspended into the water column over the 35 years of activity. The placement
                of offshore structures includes effects on water quality, benthic communities, archaeological resources, and











                 IV-62

                 fishery resources. The effects of sediment resuspension include increased water turbidities and mobilization
                 of pollutants in the water column.
                      Service vessel anchoring is assumed not to occur in water depths greater than 152 m ('500 ft) and only
                 occasionally in shallower waters. Mooring buoys may be placed near drilling rigs or platforms so that service
                 vessels need not anchor, especially in deeper water (in all water depths, vessels may also tie up directly to the
                 rig or platform). These temporarily installed anchors will most likely be smaller and lighter than those
                 described above and, thus, will be less damaging to the bottom. Moreover, installing one bijoy will preclude
                 the need for numerous individual vessel anchoring incidents.
                      Anchoring may disturb sensitive offshore benthic communities and historic and prehistoric archaeological
                 resources. Anchoring occurring as a result of pipeline and platform emplacements anti rig activities is
                 accounted for in the area disturbance estimates. During pipeline-laying operations, an array of eight 9,000-kg
                 (20,000-1b) anchors is continuously repositioned. With the proposed Live Bottom and Topographic Features
                 Stipulations (Sections II.Al.c. and II.B.l.c.), anchoring impacts from the offshore industry would be largely
                 prevented.

                 (b) Bottom Debris

                      Bottom debris is herein defined as ferromagnetic and nonferromagnetic material resting on the seabed
                 (such as cable, tools, pipe, drums, structural parts of platforms, as well as objects made of plastic, aluminum,
                 wood, etc.) that are accidentally lost, or illegally tossed, by workers from fixed structures, jack-up barges, drilling
                 ships, and during pipeline emplacement It is reasonable to assume that varying quantities of ferromagnetic
                 bottom debris may be lost, or tossed, per operation. For the purpose of the present analysis, the maximum
                 quantity of bottom debris per operation is assumed to be several tons. It is estimated that several tens of
                 thousands of tons of bottom debris (both ferromagnetic and nonferromagnetic) have been deposited on the
                 seafloor as a result of prior OCS oil and gas activity. Oil and gas activity on the Gulf of Mexico OCS as a
                 result of future OCS activities for the next 35 years will likely add several thousands of tons to the amount of
                 bottom debris on the seafloor. This bottom debris will be mitigated to some extent by seafloor clearance
                 associated with structure removals and regular inspection and burial of pipelines (Alpert@ '1990). Extensive
                 analysis of remote-sensing surveys withmi developed blocks indicates that the majority of ferromagnetic bottom
                 debris associated with OCS exploration and development activities falls within 455 m (1,500 ft) of the
                 structure/jack-up/lay barge.
                      Underwater OCS ferromagnetic debris may result in the masking of magnetic signatures from historic
                 period shipwrecks. Bottom debris may also result in the damage or loss of commercial fishing, equipment, gear
                 (primarily nets), and/or fisheries catch.
                      Most financial losses to Gulf fishermen from bottom debris and fishing gear conflicts are covered by claims
                 made to the Fishermen's Contingency Fund (FCF) (See Section 13.3.d.(3)(f) for a detailed discussion of the
                 FCF). The average claim-processing time has been reduced from as much as seven months to less than 50 days
                 after NMFS receives the completed claim. During FY 88, 113 claims of conflict between fishing and offshore
                 off and gas development were processed with 87 percent being approved for a total of $550,936 to the
                 fishermen; FY 89, 172 claims with 86 percent approved for $783,372; FY 90, 193 claims with 83 percent
                 approved for $504,396. Although Gulf fishermen are experiencing some economic loss from:gear conflicts, the
                 economic loss for a fiscal year has historically been less than 1 percent of the value of that same fiscal year's
                 commercial fisheries landings (Jackson, written comm., 1991; Davenport, written comm., 1991).

                 (c) Space-Use Conflicts

                      In addition to space-use conflicts from platform installations that result only from the proposed action,
                 fishermen are unable to trawl in areas occupied by existing structures (for further discussion of space-use
                 conflicts, see Section IV.A.2.d.(3)). Commercial fish trawling in the Gulf of Mexico is performed in water
                 depths less than 152 m. The presence of a production platform, with a surrounding 100-m navigational safety
                 zone, results in the loss of approximately 6 ha (15 ac) of trawling area to commercial fishermen and causes












                                                                                                                            IV-63
                space-use conflicts (USDOI, MMS, 1991a). It is estimated that during the peak year approximately 15,126 ha
                (37,361 ac) will be unavailable to commercial fishing in the CPA and 1,602 ha (3957 ac) unavailable to
                commercial fishing in the WPA. This assumption is based on all structures in place in less than 455 in of water
                in the first year after proposed Sales 142 and 143, respectively. Platforms in water depths greater than 455 in
                are engineered differently due to special requirements of deep-water technology.
                    Commercial fishing may also conflict with offshore oil and gas development when trawls and bottom-set
                longlines are fished on top of pipelines and pipeline valves. These hangs can result in loss of catch, in damage
                to fishing gear, and potentially in the rupturing of the pipeline. A recent issue of concern to both Federal and
                State agencies stems from several accidents involving commercial fishing vessels striking exposed gas pipelines
                in Louisiana State waters. In two incidents, loss of life (18 persons) occurred. The Department of
                Transportation (DOT) is examining these events. In an attempt to improve navigational safety and to reduce
                the hazard noted above, Congress enacted a new law requiring maintenance of the I in (3.3 ft) minimum burial
                depth. In addition, the act requires operators to report annually to the Secretary of DOT on each pipeline's
                age, location, and condition. Present OCS regulations require operators to bury all pipelines greater than 22
                cm (8.625 in) in diameter and installed in water depths less than 60 in (200 ft) to a depth of 1 in (3.3 ft). It
                is assumed that all pipelines and pipeline valves will be constructed, buried, and maintained according to the
                new regulations.

                (d) Aesthetic Interference

                    Oil and gas drilling rigs and production platforms within 10 mi of shore can be seen from shore on a clear
                day. A preponderance (more than 80%) of the nearshore Federal lease tracts within 10 mi of the coast of
                Louisiana, Mississippi, and Alabama are under lease and many are actively producing off and gas. As many
                as 100 production platforms are located on Federal lease tracts within 10 mi of the Louisiana coastal
                shorefront. Seaward of the barrier islands off Mississippi and Alabama there are 7 existing platforms producing
                oil and gas on Federal lease tracts within 10 mi of shore. It is estimated that 169 new production platforms
                will be installed in Subareas C-1 and C-3 (Table IV-3) by the year 2027 resulting from the OCS leasing
                program. Probably 5 percent or less, or 6 of these structures, will be installed within 10 mi of shore or within
                sight of the coastal shorefronts of Louisiana, Mississippi's outer islands, or Alabama's barrier islands.
                (e) Offshore Operational Wastes

                    The largest quantities of operational wastes from offshore oil and gas exploration and production activities
                include produced water, drilling fluids and cuttings, ballast water, and storage displacement water. Othermajor
                wastes include the following: from drilling--waste chemicals, fracturing and acidifying fluids, and well
                completion and workover fluids; from production--producedsand, deck drainage, and miscellaneous well fluids
                (cement, BOP fluid); and from other sources--sanitary and domestic wastes, gas and oil processing wastes, and
                miscellaneous minor discharges. Section IV.A-2.d.(5) describes what is known about the generation,
                composition, present disposal practices, and fate of offshore discharges for each major operational waste. This
                section also provides the basic assumptions for the proposed actions regarding quantities generated per activity,
                such as drilling fluid volumes per well drilled, and projected disposal methods. It is assumed that these
                assumptions are applicable to all future OCS Program operations. This section describes major contaminants
                found in each waste type. In particular, the section describes what is known about NORM generated as a
                result of oil and gas extraction processes. Current efforts to study disposal options of NORM-contaminated
                wastes are also outlined.
                   Tables IV-7 and IV-8 provide scenario projections as part of the OCS Program scenario for each major
                operational waste. These projections provide volumes of waste generated from future OCS drilling and
                production operations. Projected disposal quantities (overboard disposal quantities and onshore disposal
                volumes) are based on the assumption that the USEPA!s proposed effluent regulations described in Section
                I.B.3.d.(3)(e) will be promulgated. In the development of all estimates of future discharges and disposal











                 IV-64

                 methods, MMS assumes that these proposed effluent limitations are finalized and that USEPNs preferred
                 option for each waste, as identified in the proposed rule (40 CFR 435), win be chosen.
                      The major sources of contamination from drilling operations are the drilling fluids, or "muds," and cuttings
                 from the drill bit. The quantities of drilling fluids estimated to be generated from all OCS weR drilling activities
                 occurring in the 35-year life of the proposed actions are 76,642,000 bbl in the CPA and 51,503,000 bbl. in the
                 WPA_ Of these amounts, 62,770,000 bbl will be discharged into surrounding offshore waters in the CPA and
                 42,181,00.0 bbI will be discharged directly in the WPA_ The remaining quantities generated (19%) are assumed
                 to require onshore disposal because of effluent guideline requirements. Estimates of quantities of drill cuttings
                 generated from all future OCS drilling operations in the CPA are 18,250,000 bbl, with 1,077,000 bbI generated
                 during the peak-year drilling activity. Estimates of drill cuttings generated in the WPA are 12,715,000 bbl, with
                 856,000 bbI discharged during peak-year drilling operations.
                      Produced water (also known as production water or produced brine) is the total water discharged from
                 the oil and gas extraction process. It is comprised of the formation waters, injection water (if used for
                 secondary oil recovery and broken through into the oil formation), and various chemicals added during the oil
                 and water separation process. Produced water can constitute from 2 to 98 percent of the waste stream of a
                 producing field.
                      Offshore produced water may be reinjected into the formation or treated to decrease its oil content and
                 then discharged into offshore surface waters. Offshore treatment facilities receive produced waters from a
                 number of wells and are often centralized within a field or a number of fields. For example, in 1983, only 20
                 percent of existing offshore structures discharged produced waters; the other facilities thereby transporting their
                 produced waters to these structures.
                      Although much of the water produced from OCS oil and gas operations is discharged offshore, some of
                 the water is piped ashore and then treated and disposed of at coastal separation facilities. (Section
                 IV.13.1.c.(3)(c) discusses onshore disposal of produced waters.) About 20 percent of the produced water
                 volume estimated to be generated offshore in the CPA under the OCS Program scenario is expected to be
                 shipped into Louisiana State waters for disposal.
                      Projections of the amount of produced water generated from operations associated with total OCS Program
                 production during the 35-year life of the proposed actions is provided in Tables IV-7 and IV-49, CPA and WPA
                 respectively. Subtracting the produced water volume expected to be brought onshore in Louisiana for disposal
                 from the total volume generated in the CPA, the amount of produced waters projected to be discharged into
                 CPA and WPA offshore waters is about 9,820 MMbb1 and 2,450 MMbbl, respectively.
                      Solid wastes associated with OCS activities include production sands, salvaged and discarded tubular pipes,
                 pipe scale, and tank-bottom sludge.
                      Total volumes of produced sands generated from all future OCS Program oil and gas production during
                 the 35-year life of the proposed actions are projected to be 2,730,000 bbl in the CPA and 602,000 bbl in the
                 WPA. Section IV.13.1.c.(3)(c) discusses onshore disposal of this waste. It is expected that 100 percent of
                 produced sands will be shipped onshore for disposal.
                      Other solid wastes, such as oil-field equipment (used filters, drums, etc.), cement bags, crates, plastics, and
                 a variety of domestic wastes, are collectively characterized as trash and debris. Trash and debris generated
                 offshore from OCS oil and gas activities (metal drums and plastic containers, chemical mud bags, plastic shrink
                 wrap, cardboard boxes, glass, and cans) can adversely affect marine fish and wildlife resources, fishing
                 operations, and beaches if accidently lost or illegally disposed of into the offshore marine environment. Even
                 when properly disposed of in approved landfills onshore, future OCS Program-generated trash can affect the
                 useful life of diminishing coastal landfills and may affect wetlands loss, land use, and coastal water quality.
                      Volunteer cleanups of coastal beaches have been removing an estimated ton or more of human-generated
                 trash per mile of beach in Texas and Louisiana. Although.all Gulf user groups, as well as beach users
                 themselves, are known contributors to the problem, it has been estimated that 10-12 percent of the trash
                 removed from along the Texas and Louisiana shorefront comes from oil and gas operations in the Gulf of
                 Mexico (USEPA, 1990; Herbert, personal comm., 1991). Offshore disposal of trash and debris from oil and
                 gas operations in the Gulf is strictly prohibited by Federal and international regulations; therefore, no
                 assumptions will be made on quantities of trash and debris likely to be lost from future oil and gas operations
                 entering the marine environment Although assumptions of amounts lost are not made, it is fully recognized











                                                                                                                               IV-65

               that accidents, careless operations, and illegal dumping of solid waste from oil and gas operations will continue
               to exacerbate solid wastes, adversely impacting the Gulf and its associated coastal areas. Although the oil and
               gas industry is making strides in reducing trash loads generated offshore through widespread use of bulk storage
               and reusable containers, and the implementation of comprehensive recycling programs by some operators, large
               quantities of operational and galley waste are still returned to shore for disposal in approved landfills.
                    Liquid domestic wastes are waste waters originating from sinks, showers, laundries, and galleys, as well as
               wastewater from safety shower and eye-wash stations and fish-cleaning stations. Sanitary wastes are composed
               of human body wastes from toilets and urinals. The volume and concentration of sanitary wastes will vary
               widely with time, occupancy, platform characteristics, and operation situation. In general, a typical manned
               platform will discharge 0.075 m3 per person each day of treated sanitary wastes and 0. 110 m3 per person each
               day of domestic wastes (USEPA, 1991). Total volumes of domestic and treated sanitary discharges from all
               exploration, development, and production operations projected to occur in association with the future OCS
               Program can be found in Tables IV-7 and IV-8. Discharges from service vessels, which are estimated at 0.227
               1113 per person per day, are not included in these figures (NERBC, 1976). All liquid domestic and treated
               sanitary wastes are discharged overboard. It is expected that such discharges are rapidly diluted and dispersed.

               Effects of Offshore Discharges

                    A number of studies have investigated the fate and effects of OCS discharges around production platforms
               in open waters (USDOI, MMS, 1990b). Major studies have included the Offshore Ecology Investigation in
               Louisiana Waters conducted by Gulf Universities Research Consortium (Ward et al., 1979); the Central Gulf
               Platform Study of the continental shelf off Louisiana conducted by Southwest Research Institute (Bedinger,
               1981); the Buccaneer Field Study conducted off Galveston, Texas, by the National Marine Fisheries Service
               (Middleditch, 1981); and, most recently, the Produced Water Study conducted by Batelle for the American
               Petroleum Institute (Neff et al., 1989). Although focusing on estuarine waters, Raba" et al. (1991) did
               examine a platform in nearshore waters off Louisiana. This information is included here, when applicable.
               The three studies conducted prior to 1989 have all been heavily reviewed and critiqued (USDOI, MMS, 1990b).
               Interpretation of the study results must factor in these criticisms and the fact that water depths in all five
               studies are less than the average depth of the platform locations projected from the Base Case. The Buccaneer
               Field (Middleditch, 1981) is in 21 in; the Eugene Island Block 105 and the Lake Pelto sites studied by Neff et
               al. (1989) are in water depths of 8.5 in and 3 in, respectively; and the Eugene Island Block 18 platform
               (Raba" et al., 1991) is in 3 in of water.
                    Despite the flaws noted in these existing studies, they still can provide some insight into the fate and effects
               of OCS offshore operational discharges. The following summarizes the conclusions of the five studies:
               (1) Areas around many of the production platforms studied showed elevated concentrations of components
               that could have been from the platform operations. None of the studies found detectible trace metal or
               petroleum hydrocarbon contamination of waters and sediments beyond 200 m from the platform. (2)
               Decreases in faunal diversity or in the number of benthic infauna were documented around some platforms
               out to 300 in but, for most of the studies, not beyond small areas near the platforms. (3) The broad areas that
               were studied in the Central Gulf were often characterized as contaminated with pollutants from man's activities.
               Some implicated the Mississippi River as the probable source (Bedinger, 1981); others attributed it to the oil
               and gas industry. Neff et al. (1989) found barium present in sediments in his study area at concentrations
               substantially higher than expected of clean sediments. Neff projected that the excess barium may have been
               from areawide platform discharges of barium-laden drilling muds and produced waters. In two reports (Brooks,
               1979; Brooks et al., 1977), Brooks concluded that produced waters are an important source of light petroleum
               hydrocarbon contamination in Texas-Louisiana shelf waters, particularly large amounts of low-boiling aromatics
               such as benzene and toluene.
                    Given the above, the following generalizations about expected production platform impacts due the future
               OCS Program activities are made: (1) Moderate petroleum contamination of superficial sediments will occur
               around production platforms. This contamination is likely to be at least out to 20 in, and possibly as far out
               as 200 in, particularly in very shallow inner shelf sites. (2) Future activities in the Gulf associatcd with the











                  IV-66

                  OCS oil and gas industry are contributing to some regional contamination of waters and sediments in the
                  Central Gulf of Mexico.
                       The MMS is preparing to examine the sublethal, chronic, long-term impacts of discharges around off and
                  gas production sites. The area that will be studied is thenorthwestern Gulf of Mexico, far enough west to be
                  outside of the constant, confounding influences of the Mississippi River plume. Besides using standard
                  methodologies that assess the fate and effect of OCS discharges, this multiyear suite of studies will examine
                  the biological uptake, accumulation, toxicity, and metabolism of contaminants in the discharges. The studies
                  will hopefully clarify many of the issues raised by earlier efforts, specifically regarding any chronic, sublethal
                  perturbations that may be associated with long-term OCS Program production sites.

                       Air Emissions


                       Offshore air emissions related to the OCS program result from platform operations; drilling of
                  development, exploration, and delineation wells; helicopters, service vessels, shuttle tanker and barging of crude
                  off. Other air emissions result from catastrophic events such as oil spills and blowouts. Emissions related to
                  OCS operations occur mainly from combustion or burning of fuels and natural gas anti from venting or
                  evaporation of hydrocarbons. The combustion of fuels occurs primarily on diesel-powered generators, pumps,
                  or motors and from fighter fuel motors. Venting or evaporation of hydrocarbons occurs during loading, storage,
                  and transportation of crude off. Other emissions of hydrocarbons occurs during evaporation from oil spills and
                  discharge of bilge water, and direct release of gases during blowouts. Emission rates for OCS infrastructures
                  are presented in Section IV.A.2.d.(7). Total air emissions over the 35-year OCS program are listed in Tables
                  IV-7 and IV-8.
                       Emission factors of primary pollutants for accidental releases of oil or blowouts are presented also in
                  Section IV.A.2.d.(7). These catastrophic events generally produce high-level emissions over a very short time
                  in a localized area. Events such as oil spills or blowouts, with or without fire, are nonroutine in nature and are
                  unpredictable. The release of air pollutants from oil spills is high during the first hour and decreases rapidly
                  thereafter. A blowout that results in a gas discharge without fire releases only hydrocarbons, natural gas, or
                  hydrogen sulfides if present If the blowout occurs with fire, combustion by-products, including an primary
                  pollutants, would be released. The number of blowouts estimated to occur during the OCS program are 130
                  in the CPA and 74 in the WPA (Tables IV-7 and IV-8).

                  (g) Noise

                       In addition to noise emissions from OCS oil and gas activities that result only from the proposed action,
                  noise emissions originate from the on-going OCS program (for general discussion of noise levels see Section
                  IV.A.2.d.(7)). Noise emissions are associated with the operation of offshore platforms, drilling rigs, seismic
                  surveys, and helicopter and service-vessel traffic (Helicopter Safety Advisory Conference, 1991). The absolute
                  amount of noise emissions from the on-going OCS program is unknown and may vary seasonally. Noise
                  emissions associated with non-OCS activities are variable and may be loud or soft, transient or constant (in
                  particular areas such as entrance fairways to major harbors). Noise emitted from these activities may also
                  affect fish resources, marine turtles and mammals proximate to the activities.

                  (h) Blowouts

                       Section IV.A.2.d.(8) provides general information on blowout events, their expected duration, statistics on
                  types of operations that have resulted in blowouts, and data on historical occurrences. Expected impacts
                  associated with blowouts are described, especially the potential for associated oil spills. Blowouts can occur
                  during any phase of oil development: exploratory drilling, development drilling, production, and workover
                  operations. This information was used to estimate the number of blowouts that could occur from future OCS
                  Program operations during the 35-year life of the proposed actions. Tables IV-7 and IV-8 provide the total











                                                                                                                             IV-67
              numbers projected over this time period: 130 blowouts are expected to occur in the CPA, with 7 during the
              peak year of activity-, 74 blowouts are expected to occur in the WPA, with 6 occurring during the peak year.
              (i) Offshore Spills

                  Hydrocarbon development activities that occur as a result of the OCS Program create concerns about crude
              oil, diesel, and condensate spills. A spill event can occur on OCS waters, and because of oceanographic and
              meteorological processes, it can be transported to nearshore or coastal areas. Besides spills, there are chronic
              leaks from offshore facilities, transportation, and or processing facilities. These leaks are in general less than
              or equal to 1 bbl. Materials that can be spilled during the activities include crude oil, condensates, diesel, and
              other pollutants. These spill events occur in a random fashion in time and space; therefore, any attempt in
              describing these random processes use statistical procedures and techniques. Section IV.C. presents a
              discussion of the statistical techniques, rates, probabilities, and assumptions about OCS spills in offshore areas.
              Also, the section presents details of the historic occurrence of spills, processes, and characteristics of the spins
              discussed in this document. The estimated number of occurrences of oil spills of different size categories under
              the OCS Program scenario in the CPA and WPA is shown in Tables IV-7 and IV-8.

              c. Description of Onshore/Coastal Operations and Impacting Factors

              (1) Onshore Inftastructure anti Activities

                  The high concentration of oil and gas activity that has occurred in the CPA and WPA has been
              accompanied by extensive development of onshore service and support facilities. Section IV.A.3.a. describes
              the VjTcs of onshore infrastructure operations and facilities that have been used to support these offshore
              operations. It is expected that the vast majority of the onshore service, support, and hydrocarbon-processing
              facilities already in existence will be sufficient to explore, develop, and produce the oil and gas resources that
              are projected to result from prior, proposed, and future sales in the CPA and WPA_ No new infrastructure
              is expected to be constructed in coastal areas adjacent to mature offshore areas, i.e., areas that have routinely
              experienced years of active oil production and development. There is some minor infrastructure projected to
              be constructed to support new oil and gas development operations in offshore areas not yet developed (the
              Western Gulf oil fields and the area east of the Mississippi River). Tables IV-12, IV-13, and IV-14 provide
              the number of existing and projected onshore facilities expected to be utilized to support future OCS Program
              activities by coastal subarea for the CPA, WPA, and the total Gulf, respectively.                   Subareas C-4
              (Mississippi/Alabama), W-1 (Mustang and Matagorda Islands), and W-2 (Matagorda Peninsula and adjacent
              lands) are expected to have new pipeline landfalls with associated gas processing, separation, and terminal
              facilities.
                  The future status of the existing facilities is not shown in Tables IV-12 through IV-14. This status is most
              important to socioeconomic conditions in the future. Projections of OCS Program activities in mature areas
              of the Gulf depict a significant decline in offshore operations over the next several decades, occurring in
              association with projected declines in the hydrocarbon resources of the Gulf. This offshore activity decline will
              likely lead to closures of existing onshore infrastructure in coastal areas that support existing development
              (a) Service and Construction Facilities

                  These facilities include platform fabrication yards, pipecoating yards, service bases, and heliports. No new
              facilities in any of these categories are expected to be constructed under the OCS Program scenario, as shown
              in Tables IV-12 through IV-14. In fact, both existing construction and service facilities are expected to decline
              significantly over the next several decades in association with projected declines in the hydrocarbon resources
              of the Gulf. Evidence of this trend is already appearing. During the last 4 years, for example, 4 pipeyards have
              closed and 11 platform fabrication yards have either closed or been temporarily idled. Although the total
              number of active platforms in the Gulf has been increasing each year through 1990, the rate of annual increase























                                                                                                Table IV-12

                                      onshore Scenario Information Related to OCS Program Activities in the Central Planning Area for the Years 1993-2027

                                                                                                           Onshore Subarea*
                                                                --------------------------------------------------------------------------------------------------
                                                                      C-1                C-2              C-3                C-4               W-2             Total CPA
                                                                OCS Program        OCS Program        OCS Program       OCS Program        OCS Program        OCS Program
                   onshore (Total     Peak Year)                  Activities        Activities         Activities         Activities        Activities         Activities
                   ---------------------------                   -----------       -----------        -----------       -----------        -----------        ------------

                   Oil Landings
                     Pipeline Transported Oil (KMbbl)             212      9      3,182     139      1,663    73          118      5           0      0      5,175     227
                     Shuttle Tanker Offloadings
                       From CPA                                     0      0           0     0          45      2            0     0           0      0         45        2
                       From EPA                                     0      0           0     0         488    22          42       2           0      0        530      26
                     Total Shuttle Tanker Offloadings               0      0           0     0         533    24          42       2           0      0        575      28
                     Barge Offloadings                         3,410     150      1,710     70       1,540    70             0     0        170     10       6,828     299
                   onshore Accidents
                     onshore Oil Spills
                       >1 and <50 bbl                         -*NA       NA          NA     NA          NA    NA          NA     NA          NA     NA       20-35        2
                       >50 and <1,000 bbl                     ****NA     NA          NA     NA          NA    NA          NA     NA          NA     NA         3-5        1
                       >1,000 bbl                             ****NA     NA          NA     NA          NA    NA          NA     NA          NA     NA            1       1
                   support Activities
                     Helicopter Land Crossings (1,000's)       3,434  /  167      7,822     379      6,868    333         572    28         382     19      19,079     925
                     Service Vessels
                       Landings (1,000's)                         248 /  13          250    13         157      8         19       1         26       1        701      36
                       Discharged Bilge Water (B liter)        1,454  /  58       1,454     58         930    58          116      6        174       6      4,076     209
                   onshore Disposal of offshore Wastes
                     Produced Sands (1,000 bbl)               -***NA  /  NA          NA     NA          NA    NA          NA     NA          NA     NA       2,731     120
                     Produced Waters (KMbbl)                       94 /  NA            1    NA       2,344    NA             0   NA            0    NA       2,439      NA
                     Drilling Fluids (1,000 bbl)              **-*NA  /  NA          NA     NA          NA    NA          NA     NA          NA     NA       13,872    804

                   Onshore Infrastructure Construction
                   (existing/new)
                     Refineries                                     5 /    0           3     0            7     0            2     0         14       0         31        0
                     Gas Processing Plants                         13 /    0           8     0            5     0            0     2           0      0         26        2
                     Terminals                                     32 /    0         23      0          25      0            0     1           0      0         80        1
                     Pipe Yards                                     3 /    0           4     0            2     0            0     0           3      0         12        0
                     Platform Yards                                 3 /    0           7     0            1     0            3     0           6      0         20        0
                     Service Bases                                  5 /    0         10      0            4     0            4     0           5      0         28        0
                     Separation Facilities                         23 /    0         10  /   0          17      0            0     2           0      0         50        2
                     Navigation channels                            4 /    D           4 /   0          10      0            3     0           3      0         24        0
                     Pipeline Landfalls                            49 /    0         53  /   0          42      0            2     3**       14       0        160        3
                     onshore Pipelines (km)                    1,453  /    0      1,571  /   0       1,246      0         179    48          NA       0      4,449      48
                     Helicopter Hub                                 8 /    0           8 /   0            4     0            1     0           6      0         27        0

                         See Figure IV-1.
                         The oil transported to Subarea C-4 by pipeline     includes 18 KMbbl originating    in the EPA. Also,     two new pipeline
                         landfalls in C-4 (one oil and one gas) will be     transporting some hydrocarbons from the EPA, and       a proportionately  small
                         amount of service vessel and helicopter traffic will utilize shore bases in coastal areas adjacent to the CPA for            activities in the EPA.
                         Assumptions are derived from historical trends but are not based on statistical analyses.
                         Data are not shown by subarea because of statistical uncertainties.
























                                                                                          Table IV-13

                                Onshore Scenario information Related to OCS Program Activities in the Western Planning Area for the Years 1993-2027

                                                                                                          Onshore Subareas*
                                                              --------------------------------------------------------------------------------------------------
                                                                     W-1               W-2              C-1               C-2                C-3            Total WPA
                                                              OCS Program        OCS Program       OCS Program        OCS Program       OCS Program        OCS Program
                                                                Activities        Activities         Activities        Activities        Activities         Activities
                  Onshore (Total / Peak Year)                 -----------         -----------      -----------        -----------       -----------         -----------
                  ----------------------------

                  Pipeline Transported Oil (MMbbl)              242      a        673     23            0    0          133     5            0    0        1,049     36
                  Shuttle Tanker Traffic (trips)                437    15         434     15          73     3           0      0          16     1         960      33
                  Barge Traffic (trips)                           0      0        607     21         152     5           0      0            0    0         759      26
                  Onshore Accidents
                    oil spills
                      >1 and <50 bbl                          ***NA    NA          NA     NA          NA    NA          NA      NA         NA     NA        5-7        1
                      >50 and <1,000  bbl                     ***NA    NA          NA     NA          NA    NA          NA      NA         NA     NA           1       1
                      >1,000 bbl                              ***NA    NA          NA     NA          NA    NA          NA      NA         NA     NA           1       1
                  Support Activities
                    Helicopter Land Crossings (1,000's)         848    32        1,007    38         795    30           0      0            0    0        2,650     100
                    Service Vessels
                      Trips (1,000's)                             64     4         88      5          47     3          13      1            0    0         211      12
                      Discharged Bilge Water (B liter)          203    13         279     16         149    10          41      3            0    0         669      38
                  OCS Waste Disposal
                    Drilling Fluids (1,000 bbl)                 ***NA / NA           NA   / NA          NA / NA           NA     NA          NA    NA       9,322      619
                    Produced Sands (1,000 bbl)                  ***NA  / NA          NA   / NA          NA  / NA          NA     NA          NA    NA          602     20

                  Onshore Infrastructure Construction
                  (existing/new)
                    Refineries                                    6      0         14      0            5    0           3      0            2    0          30        0
                    Gas Processing Plants                         0      0          2      0            4    0           2      0            01   0            8       0
                    Terminals                                     5      2          9      1            2    0           0      0            0    0          16        3
                    Pipe Yards                                    5      0          3      0            3    0           4      0            2    0          17        0
                    Platform Yards                                5      0          6      0            3    0           7      0            1    0          22        0
                    Service Bases                                 7      0          5      0            5    0          10      0            0    0          27        0
                    Separation Facilities                         5      0          a      0            3    0           0      0            0    0          16        0
                    Navigation Channels                           6 1    0          3      0            4    0           4      0            3    0          20        0
                    Pipeline Landfalls                            5      2         14      1            2    0           0      0            0    0          21        3
                    Onshore Pipelines (km)                        NA   80          NA     40          NA     0           0      0            0    0          NA      120
                    Helicopter Hub                                6      0          6      0            8    0           0      0            0    0          20        0

                      See Figure IV-1.
                      Assumptions are derived from historical trends but are not       based on statistical  analyses.
                      Data are not shown by subarea because of statistical uncertainties.





















                                                                                                                     Table IV-14

                                                           Onshore Scenario Information Related to OCS Program Activities in the Gulf of Mexico for the Years 1993-2027

                                                                                                                            Onshore Subarea*
                                                                        -----------------------------------------------------------------------------------------------------------------
                                                                               C-1                 C-2               C-3                C-4                  W-1              W-2                 Total
                                                                        OCS Program         OCS Program         OCS Program         OCS Program         OCS Program       OCS Program         OCS Program
                        Onshore (Total      Peak Year)                  Activities          Activities           Activities         Activities           Activities       Activities          Activities
                        ---------------------------                     -----------         -----------         -----------         -----------          -----------      -----------         -----------

                        Oil Landings
                          Pipeline Transported Oil (MHbbl)                212       9       3,315     145      1,663     73           118       5        242         8     673     23         5,981      262
                          Shuttle Tanker offloadings
                            From CPk                                         0      0            0      0         45        2           0       0            0       0        0      0          45         2
                            From EPA                                         0      0            0      0        488     22           42        2            0       0        0      0         530       26
                            From WPA                                      73        7            0      0         16        2           0       0        437      10       434     14          960       33
                          Total Shuttle Tanker Trips                      73        3            0      0        549     22           42        2        437      17       434     17         1535       61
                          Barge Offloadings                            3,562   / 155        1,710     70       1,540     70             0       0            0       0     777     31         7,587      325
                        Onshore Accidents
                          Onshore Oil Spills
                            >1 and <50 bbl                            ****Nk   / NA            NA  /  NA          Nk   / NA           Nk      NA          NA      Nk        NA     NA         25-40        2
                            >50 and <1,000 bbl                        ****Nk   / NA            NA  /  NA          Nk   / NA           Nk      NA          NA      NA        NA     NA          4-6         1
                            >1,000 bbl                                ****NJL    NA            NA     N&          NA     NA           NA      NA          NA      NA        NA     NA             2        1
                        Support Activities
                          Helicopter Land Crossings (1,000's)          4,229     199        7,822     379      6,868     333          572     28         848      32     1,389     51       21,729     1,025
                          Service Vessels
                            Dockings (1,000's)                            295    14           263     11         157     10           19        1         64         4     114       6         912       48
                            Discharged Bilge Water (B liter)           1,603     68         1,495     61         930     58           116       6        203      13       453     22         4,745      247
                        Onshore Disposal of Offshore Wastes
                          Produced Sands (1,000 bbl)                  *-NA       NA            NJL /  NA          NA   / Nk           NK      NK          NA   /  NA        NA     NA         3,333      140
                          Produced waters (MMbbl)                         94   1 NK              1 /  NA       2,344   / NA             0     Nk             0 /  NA          0    NA         2,439      NA
                          Drilling Fluids (1,000 bbl)                 ****Nk   / Nk            NK  /  Nk          NA   / Nk           Nk      Nk          Nk   /  NA        NK     NA       23,194     1,423

                        Onshore Infrastructure Construction
                        (existing/nev)
                          Refineries                                         5 /    0            3 /    0            7 /    0           2       0            6 /     0      14       0          37         0
                          Gas Processing Plants                           13   /    0            8 /    0            5 /    0           0       2            0 /     0        2      0          28         2
                          Terminals                                       32        0          23  /    0         25        0           0       1            5 /     2        9      1          94         4
                          Pipe Yards                                         3      0            4 /    0            2      0           0       0            5 /     0        3      0          17         0
                          Platform Yards                                     3      0            7 /    0            1      0           3       0            5 /     0        6      0          25         0
                          Service Bases                                      5      0          10  /    0            4      0           4       0            7 /     0        5      0          35         0
                          Separation Facilities                           23        0          20  /    0         17        0           0  /    2            5 /     0        8 /    0          63         2
                          Navigation Channel   6                             4      0            4 /    1         10        :           3  /                 6 /     0        3 /    0          30         0
                          Pipeline Landfalls                              49        0          53  /    0         42   1                2  /    3            5 /     2      14       1         165         6
                          Onshore Pipelines (kzQ                       1,453        0       2,571  /    0      1,246   /    0         179  /  40          NA   / 80         NA     40         4,449      168
                          Helicopter Bub                                     8      0            a /    0            4 /    0           1  /    0            6 /     0        6      0          33         0

                              See Figure IV-1.
                              The oil transported to Subarea C-4 by       pir  line  includes 18 MMbbl originating      in the EPA. Also, two new pipeline
                              landfalls in C-4 (one oil and one gas) . 11 be         transporting some hydrocarbons from the EPA, and a proportionately              small
                              amount of service vesselfand helicopter traffic will utilize shore bases in coastal areas adjacent to the CPk for                      activities in the EPA.
                              Assumptions are derived rom historical trends but are not based on statistical analyses.
                              Insufficient data are available to permit calculations for individual coastal subareas.











                                                                                                                                 IV-71

                has slowed markedly in recent years. Whereas from 1977 to 1985 the increase in the total number of platforms
                averaged 5.2 percent per annum; from 1986 to 1990, the rate of increase dropped by one-half to 2.6 percent.
                During the first six months of 1991, the rate of increase was 1.6 percent if projected to a full year. The MMS
                predicts the number of active platforms to begin to decline each year beginning in 1993. The reader must keep
                in mind that the changes in the number of active platforms in the Gulf from one year to the next reflect both
                the number of new platforms added and the number of old platforms removed during the year. The decline
                in the rate of increase in the number of platforms seen during the past several years could, to some extent, be
                the result of increased rates of platform removal rather than solely to decreased rates of new platform
                installations. Although increased rates of platform removals may be a factor contributing to declines in annual
                active platform counts, MMS does project a decline in the number of new platforms that will be installed each
                year. This decline should become precipitous during the second half of the first decade of the next century.
                Both platform removal and a decline in new platform installations are related to the onshore infrastructure
                decline.
                     Although the number of miles of pipelines installed in the Gulf has shown no apparent trend during the
                past 20 or so years, pipeyard activity has declined as witnessed by the closure of 4 out of 26 operating pipe
                yards in the Gulf area during the past several years. The pipecoating industry anticipates no expansion in
                business during the timeframe of the proposed actions (Jones, personal comm., 1991). This outlook is
                supported by MMS projections, which show a decline in the number of miles of pipelines installed each year
                in the Gulf over the next few decades (Table IV-7).
                     Another factor that could contribute slightly to the decline in traditional construction facility activity levels
                over the life of the proposed actions is the use of floating production systems, rather than fixed platforms and
                pipelines, in the Gulf for deep-water operations. "Me use of these production facilities will replace the
                platforms that would otherwise be needed for producing offshore fields, and will reduce the rate of new
                pipeline installations because production from floating production systems is assumed to be transported to
                shore by shuttle tanker. Also, industry has been increasingly using compliant structures for deep-water
                production. These structures, which use less steel than traditional rigid platforms, result in less activity at
                fabrication facilities. Industry has also been purchasing some compliant structural components from overseas
                manufacturers.
                     Although it is difficult to quantify the magnitude of the projected decline in the number of platform
                fabrication facilities over the 35-year time period analyzed, the range is likely to go from a few closures to a
                major decline in the industry. If a major decline occurs, this trend will not likely be initiated until the first
                decade of the next century. This document assumes that 90 percent of the platform fabrication yard capacity
                and 88 percent of the pipeyard capacity will be used for all future OCS Program activities during the life of
                the proposed actions.
                     Declines in the use of service facilities is also anticipated, based on the decline in the amounts of OCS
                activities that will require support from onshore. It is difficult to anticipate the closures of individual service
                bases, since the locations indicated in Table IV-15 could include up to several docking areas used by different
                oil and gas exploration and production companies and/or mud companies. It is likely, however, that some dock
                space will be abandoned during the next few decades. With the increasing interest in deep-water tracts, it is
                likely that service base activity will remain high at locations that can be used by deeper draft service vessels.
                These bases include Galveston, Texas, and Venice, Cameron, Fourchon, and Berwick, Louisiana (the base at
                Fourchon will be accessible for deep draft service vessels pending implementation of the COE's plans to
                deepen the channel to 5.5-6.7 m). Any service base closures are assumed to occur at other locations. It is
                assumed that, during the 35-year life of the proposed actions, 60 percent of the existing service base capacity
                will continue to be used to support OCS Program activities. This is based on the ratio of tideland to OCS off
                production for the year 1989.
                     Heliport closures are not expected to occur, although the total number of trips will decline. The number
                of helicopter trips occurring to support OCS operations is also expected to decline during the life of the
                proposed actions. In 1989, approximately 2,000,000 trips took place in the Gulf area, most of which were
                related to offshore oil and gas operations. An estimate of the average activity level expected during the life
                of the proposed actions can be obtained by adding the total number of projected trips in the CPA and WPA
                (Tables IV-7 and IV-8) and dividing by the 35-year life of the proposed actions. These calculations show an











                  IV-72

                  average annual activity level of 1,100,000 trips, or nearly a 50 percent reduction compared to current activity
                  levels. These numbers do not include the use of heliports located in Louisiana, Mississippi, and Alabama to
                  service projected OCS operations in the Eastern Gulf. Activity levels in the EPA, however, are expected to
                  be muchless than levels in either the CPA or WPA (Table IV-9), and including EPA-related activity, would
                  not change the numbers significantly. It is assumed that 90 percent of Gulf fleet helicopter trips are related
                  to OCS Program activities.
                      Although the total number of helicopter trips is expected to decline, the duration of the typical trip will
                  increase as activity moves into deeper water. Travelling times to deep-water activities Will obviously be much
                  longer. This document assumes that, although total trips will decline by about 50 percent over the life of the
                  proposed actions under the OCS Program scenario, the total amount of flying time will remain constant.
                  Therefore, no major declines in the size of the helicopter fleet is projected, and no helipoms will close.

                  (b) Processitig and Storage Facilities

                      As discussed in Section IV.A-3.a.(2)(d), a terminal is defined as the onshore metering station and storage
                  site of liquid hydrocarbons transported to shore by either barges or pipelines. Four new terminals are
                  projected to be built to meter and store off from the four new oil pipeline systems making landfall in onshore
                  areas adjacent to offshore areas not yet developed (Section IV.B.l.c.(2)). A new terminal will be built to
                  support the projected oil pipeline landfall in Jackson County, Mississippi. This terminal could be located in
                  wetland areas. Three new terminals will be built in Texas to support the off pipeline systems terminating along
                  the Texas Coast. One terminal is assumed to be constructed on Mustang Island, one on Matagorda Island,
                  and one across the bay from the Matagorda Peninsula. Since OCS barging activity is expected to remain at
                  current levels, no new barge terminals are expected.
                      Although new terminals will be constructed in onshore areas distant from the major concentration of
                  support infrastructure, some existing terminals are projected to be closed as a result in the projected decline
                  in OCS oil resource production. Future volumes of OCS oil and condensate transported by pipeline will
                  decline in proportion to the decline in resources projected to be produced. Most pipeline systems in the Gulf
                  carry off from a number of leases and fields at any one time. It is assumed that enough oil from future leases
                  will be transported through most existing pipeline systems to maintain the system in operation along with its
                  shoreline terminal. This is especially true of existing pipeline systems projected to be connected to new
                  pipelines carrying oil from leases in deeper water. It is unclear what will happen with shorter pipeline systems
                  tied to one or two existing fields that will no longer carry any produced oil or gas to shore. Despite this
                  uncertainty, it is expected that some terminals will probably close in the future given the overall decline in the
                  offshore oil industry. For analysis purposes, maps of the existing and projected pipeline network were
                  compared to find pipeline systems currently making landfall that only carry oil from one or two fields located
                  close to State waters. Use of these systems is assumed to be discontinued in the next several decades and
                  associated onshore processing facilities to be shut down along with the pipeline closures. Systems discontinued
                  include 8 terminals in Louisiana, 5 in C-1 and 3 in C-2, and none in Texas. It is assumed that, for those
                  terminals remaining open, 90 percent of the capacity of existing terminals will continue to service the OCS oil
                  industry, with the remaining percentage servicing State offshore production.
                      Processing facilities include refineries, gas processing plants, and separation facilities. No new refinery
                  construction is anticipated under the OCS Program scenario. A general discussion of the factors that enter into
                  the decision to construct a new refinery and the regulatory and economic environment for new refinery
                  construction is presented in Section IV.A.3.a.(2)(a). Although the percent of refinery capacity accounted for
                  by OCS crude will decline in the future, refineries are expected to remain at current capacity by switching to
                  foreign crude sources. This has already occurred at some refineries in the Gulf area, such as the Exxon facility
                  in Baton Rouge, Louisiana, and the Chevron facility in Pascagoula, Mississippi, which almost exclusively use
                  foreign crude sources. Therefore, no decline in refinery operations are anticipated during the 35-year life of
                  the proposed actions. It is assumed that 10 percent of the refinery capacity along the Gulf Coast will be used
                  for OCS Program production over the life of the proposed action, based on the current ratio of OCS oil
                  production to all other oil sources entering the Gulf and on projected declines in OCS production in the future.











                                                                                                                             IV-73

                   As discussed in Section IV.A.3.a.(2)(b), whenever a new gas pipeline system makes landfall, a new gas
              processing plant is anticipated. Two new gas pipeline landfalls are projected for Subarea C-4 (Section
              IV.B.l.c.(2)). Applying the assumptions described in Section IV.A.3.a.(2)(b), two new processing plants are
              expected to be built under the OCS Program scenario in coastal Subarea C-4. Two processing plants, rather
              than one, are assumed to be constructed because new production from leases in offshore Subarea C-3 east of
              the Mississippi River and nearby areas of the EPA are associated with gas containing impurities (primarily
              hydrogen sulfide) that will require the construction of a separate processing facility for each field and associated
              pipeline landfall.
                   While two new facilities are assumed to be constructed in Subarea C-4 to support activities in offshore
              areas not yet developed, the utilized capacity of existing gas plants will decline and may result in closures as
              total gas production offshore declines elsewhere in the Gulf. As an operating assumption in this document,
              plants are expected to close when the utilized capacity of OCS-related gas processing plants declines to less
              than 25 percent. This number was chosen because it is the current minimum capacity at which an existing plant
              is operating. Under this assumption, 14 plants are assumed to close during the next 35 years, beginning during
              the first decade of the next century. The gas processing plants associated with OCS production are assumed
              to process only OCS gas.
                   Separation facilities are co-located with terminals or gas processing plants. However, it is anticipated that
              most oil productionwill have separation components offshore on production complexes and that future onshore
              separation will serve gas processing plants. Given this, two new separation facilities are expected to be
              constructed under the OCS Program scenario, both to be built in Mobile County, Alabama, to separate the
              water from the gas resources projected to be transported to this area.
                   There are 63 existing separation facilities located in the Texas and Louisiana coastal area, with the vast
              majority (50) occurring in Louisiana. Of these 50 facilities, there are 15 separation facilities located in
              Louisiana that have historically discharged large amounts of OCS produced waters to surrounding waters
              (Rabalais et al., 1991). Based on new State regulations that have discontinued this practice, three have closed
              recently and another nine of these will close when the fields carrying produced water to them are abandoned.
              Besides these nine closures, separation facilities located at terminals or gas processing plants win close, along
              with these facilities. Without a knowledge of the co-location of separation facilities at the terminals or gas
              processing plants projected to be closed, it is assumed that there is a 50 percent chance that a separation
              facility would be co-located. Therefore, another 11 more separation facilities will close. This total projected
              closure of separation facilities represents a significant percentage (27%) of the total number of separation
              facilities currently in operation (63).

              (2) Landings and Coastd Transport Operations

                   A general discussion of the movement of OCS liquid hydrocarbons onshore and at coastal landfalls is
              contained in Section IV.A.3.b. Tables IV-7 and IV-8 show the projected percentages of the liquid hydrocarbons
              expected to be produced under the OCS Program scenario that will be transported by pipeline, barge, and
              shuttle tanker. Tables IV-12, IV-13, and IV-14 show the number of barge and shuttle tanker landings and the
              amount of pipeline transported oil projected to occur in the various coastal subareas of the Gulf under the
              OCS Program scenario. Table IV-15 shows the number of landings of shuttle tankers and oil barges (as well
              as service vessels) by waterway and terminal.
                   Projected new offshore pipeline systems in the Gulf will result both in new pipeline landfalls and new
              onshore connected pipeline segments being installed in both the CPA and WPA. In the CPA, three new
              pipeline landfalls are projected for coastal Subarea C-4--the Mississippi-Alabama Gulf Coast in Jackson County,
              Mississippi (1--oil), and Mobile County, Alabama (2--gas). These landfalls will account for the installation of
              three onshore pipeline segments, totaling 48 kin (Table IV-12). Two of these pipelines will be used to
              transport gas and one to transport oil. In the WPA, prior sales will account for the installation of 120 kin of
              onshore pipe and three new pipeline landfalls (Table IV-13). Three new offshore oil pipelines are projected
              to make landfall in Matagorda County (Matagorda Peninsula)(W-1), Calhoun County (Matagorda Island) (W-
              1), and Nueces County (Mustang Island)(W-2).








                                                                                                                         Table XV-15

                                                                                       Waterway Usage by OCS-Related Navigation Associated With the OCS Program
                                                                                                                  for the Years 1993-2027

                                                                                                                         Number of               Number of                  Number of
                                                                                                                     service vessel                Barge                 Shuttle Tanker
                                                                                             Landings           OCS    offloadings               offloadings              CPA
                                                                                                              Usage      CPA        WPA          CPA        WPA            EPA      WPA
                                        Coastal                                                               OCS        OCS        OCS          OCS        OCS           OCS       Ocs
                                        Subarea      Waterway Usage                 Service Base/Terminal                Program    Program    Program     Program    Program    Program
                                        -------      -----------------------        ---------------------     -----    --------     --------   -------    -------     -------    -------
                                        C-1        Calcasieu ship channel                                     <10%                                                                  73
                                                                                    Cameron                            154,010      28,990
                                                                                    Lake Charles                                                 1,366       114
                                                                                    Gibbstown                                                      683         38
                                                   Freshwater Bayou                                           <10%
                                                                                    Intracoastal city                    84,580     15,920
                                                                                    Kaplan                               1,920        360
                                                   Hermentau Navigation Channel                               <10%
                                                                                    Grand Chenier                        5,770      1,090
                                                   vermilion Say/Bayou Teche                                   69%
                                                                                    Louis&                               1,920        360
                                                                                    Weeks Island                                                 1,366

                                        C-2        Atchafalaya River                                           33%
                                                                                    Amelia                               4,470        230
                                                                                    Bayou Boeuf                          2,240        120
                                                                                    Berwick                              2,240        120
                                                                                    Freshwater City                      4,470        230
                                                                                    Morgan City                        143,060      7,470
                                                                                    Gibson                                                         512
                                                   Bayou Lafourche/Belle Pass                                  42%
                                                                                    Fourchon                             24,590     1,280
                                                                                    Leeville                             13,410       700
                                                   Houma/caillou/Terrobonne                                    31%
                                                                                    Dulac                                31,290     1,630
                                                                                    H uma                                22,350     1,170
                                                                                    Theriot                              2,240        120
                                                                                    Gibson                                                         512
                                                                                    Cocodria                                                       683

                                        C-3        Barataria Waterway/LaLoutre                                <10%
                                                                                    Grand Isla                           13,110
                                                   Mize. River Gulf Outlet                                    <109
                                                                                    Hopedale                             2,190
                                                   Ries. River Passes                                         <10%                                                         533      16
                                                                                    Venice                             139,860
                                                   Empire Waterway                                             21%
                                                                                    Empire                                                       1,536
                                                   LA Loutre/st Halo/Yoclookey                                 19%
                                                   Kies. River/Harvey Canal
                                                                                    Harvey                               2,190

                                        C-4        Bayou LaBatre                                              <10%
                                                                                    Bayou LaBatre                        1,120
                                                   mobil* say                                                 <10%                                                          29
                                                                                    Mobile                               14,590
                                                                                    Theodore                             1,120
                                                   Pascagoula/Bayou Casotte                                   <10%                                                          13
                                                                                    Pascagoula                           2,240

                                        W-1        Aransas Pass                                               <20%
                                                                                    Port Aransas                                    1,870
                                                                                    Ingleside                                       20,540
                                                                                    Rockport                                        1,870
                                                   Brazos Santiago Pass                                       <10%
                                                                                    Port Isabel                                     3,730
                                                   Corpus Christi Ship Channel      Corpus Christi            <10%                  1,870                                           437
                                                   Matagorda Ship Channel                                     <10%
                                                                                    Port O'Connor                                   31,740
                                                   Port Mansfield Cut                                         <10%
                                                                                    Port Mansfield                                  1,870

                                        W-2        Freeport Harbor Channel                                    <10%                                                                  143
                                                                                    Freeport                             6,330      21,180
                                                   Houston/Galv Channel                                       <10%                                                                  217
                                                                                    surfaide                                900     3,030
                                                                                    Galveston/Texas City                 7,690      25,720                   340
                                                                                    Pelican island                       3,170      10,590
                                                   Sabine Pass Ship Channel                                   <10%                                                                  74
                                                                                    Sabine Pass                          8,140      27,240
                                                                                    Port Arthur                                                    172       267

                                                                                                              TOTAL    701,200      211,000      6,828       759          575 -     960

                                        -This number includes 530 shuttle tanker trips that originate in the EPA.












                                                                                                                            IV-75


                   Table IV-14 shows the subareas receiving oil transported from all future OCS Program production during
               the 35-year life of the proposed actions. Subarea C-2 will receive over one-half of the pipeline transported off
               produced under the OCS Program scenario; and over one-fourth of this oil is projected to make landfall in
               Subarea C-3. The other subareas in the CPA and WPA Gulf coastline will receive only proportionately small
               amounts of oil via pipeline.
                    One activity of concern under the OCS Program scenario is the repair and maintenance of older pipelines
               carrying OCS petroleum hydrocarbons in coastal waters and onshore. Figure IV-2 shows the age distribution
               of pipeline landfalls from OCS activities. This figure shows that over one-half of all pipeline landfalls are over
               20 years old. Since 1970, all pipelines have been installed with cathodic protection with sacrificial anodes to
               protect the line from corrosion. Pipelines installed before 1970 are protected by running an electric current
               through the pipeline. Although these measures greatly extend the life of a marine pipeline, and industry does
               not anticipate a widespread effort to repair all aging lines, pipeline repairs in coastal areas may be needed in
               the future. Also, pipelines can become exposed at the shoreface or on the bottom of coastal waters as a result
               of shoreline erosion and bottom scour.
                   It is difficult to obtain data on the amount of repair work that has been conducted in recent years for these
               problems because many of these pipelines were permitted with a right to perpetual maintenance, or the original
               right to maintenance had been extended years ago and has not expired. In these situations, repairs and
               maintenance operations can be conducted without obtaining permits from COE or State agencies. As such,
               records on the frequency of occurrence of these activities are not readily available. The MMS is attempting
               to collect information on these activities, and the information will be included in the EIS when it is collected
               and compiled.
                    Section IV.A.3.b.(3) describes the navigation channel network available for use by OCS-related vessel
               traffic. Table IV-15 provides projections of the average usage of all major navigational channels along the Gulf
               Coast in support of OCS activities. Seven of these channels are used by the OCS oil and gas industry more
               than 10 percent of the time: Bayou Terrebonne, Bayou Lafourche, Empire Waterway, Bayou La Loutre/St.
               Maio/Yscloskey, Vermilion Bay/GIWW 159-160, the Houma/LeCorpe/Caillou waterway, and the Atchafalaya
               River/GlWW 79-95. All of these waterways are located in Louisiana. The Vermilion Bay/Bayou Teche system
               is projected to receive the most OCS traffic under the OCS Program scenario at 69 percent OCS usage. It is
               assumed that OCS usage of these channels under the OCS Program will be 12 percent.

               (3) OnshorelCoastd Impacting Factors Related to the OCS Program Activities

               (a) Disturbances ftom the Use of Existing and New Infrastructure

                    New onshore infrastructure construction, described above, is projected to occur in Mississippi, Alabama,
               and Texas (Table IV-14). The construction of the terminal in Jackson County, Mississippi, could occur in
               coastal wetlands and result in the conversion of wetlands habitat to dry land as a result of filling operations to
               prepare the construction site. It is expected that mitigation would be required that would replace wetland
               acreage lost acre by acre because of recent regulatory wetland protection measures. Onshore construction of
               the gas processing plants and separation facilities in Mobile County, Alabama, should be sited in upland areas
               because of the availability of ample upland space. Construction of the pipelines and terminals on Texas barrier
               beaches could alter coastal sedimentation and erosion patterns if the site was protected from erosion by
               armoring of the site.
                    Construction of these onshore support bases and ancillary access facilities and all associated hydrologic
               modifications would result in some runoff and other nonpoint source pollution to the surrounding bodies of
               water. Navigation channels and canals and other bodies of water may be diked, leveed, or impounded; piers,
               bulkheads, and beach-stabilization actions may be undertaken. To construct the support facility, the site must
               be prepared, roadways and bridges may need to be built, sewage and storm water systems installed, and
               groundwater or adjoining bodies of water accessed for water use. During preparation in upland areas, the
               vegetation is cleared from the area, the topsoil exposed, and the soil profile is altered by grading and leveling
               operations. The soil is compacted by the constant movement of heavy machinery, which in turn alters the
               retention properties of the soil and gives rise to increased erosion and runoff from the site.











                        13


                        12


                        11


                        10


                         9


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                    CL
                    ir
                    CO   7
                    0
                    0
                         6
                    0


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                         0                                                             1    111P
                                                                               a&b        A,     Cb A4@, Arp
                                                      "Op CO3                               1@
                                                                      C6@ a
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                                                                      Year


                                   f OCS i elin     ndf                     et    1
             Figure IV-2. Number o       P p    e La    alls (based on Wicker  al., 989











                                                                                                                                IV-77

                   The three projected coastal pipelines in Mississippi and Alabama will all be built across coastal wetlands
              and can result in direct and indirect impacts. These impacts have been discussed in EIS 139 and 141 in Section
              IV.A.5.(3)(a), and are hearby incorporated by reference. The direct impacts of new pipeline installation
              projects in wetlands has been reduced in recent years by virtue of new pipeline projects being back-filled after
              the pipeline is installed. Back-filling, by partially filling in the canal cut and levelling spoil banks, reduces the
              amount of wetland area converted to non-wetland habitat, and reduces indirect impacts by reducing salt water
              intrusion and removing the drainage interference effects of spoil banks. Turner and Cahoon (1987) have shown
              a reduction from 2.49 ha/km of average direct impacts in the past, to projected impacts of 0.68 ha/km in the
              Chenier Plain and 1.05 ha/km in the Deltaic Plain with backfilling.
                   Once constructed, the new infrastructure along with all existing infrastructure, as described above in
              IV.B.I.c.(1) can generate air emissions, routine point and nonpoint source discharges, and other operational
              liquid and solid wastes, as well as experience accidental spills, which can contaminant the coastal environment,
              as well as affect coastal landfill capacities. Other activities associated with onshore infrastructure that could
              affect the coastal environment include the movement of oil via pipeline, barge, and shuttle tanker; the
              offloading of oil at terminals; and the use of navigation channels by OCS-related traffic.
                   Operational discharges are discussed under each facility description in Section IV.A.2.d.(3).but are
              summarized here also. At service bases and marine terminals, hydrocarbons and other pollutants are
              discharged in the bilge and ballast waters of support vessels docking at these facilities. The bases and support
              vessels also contribute contaminants through their use of antifouling marine paints and through accidental
              oil-spillage events and the release of heavy metals and contaminated sludge.                       Pipecoating yards,
              platform-construction facilities, and repair and maintenance yards contaminate surroundingwaters by releasmig
              thermal effluents, radioactive substances, antifouling paint chemicals, heavy metals, and a variety of process
              waters, as well as solid waste such as packaging materials, metal scraps, and other debris. Gas processing
              plants and refineries discharge a number of types of waste waters, including cooling and boiler waters, sanitary
              and domestic waste waters, and process waters. These waters may be contaminated with dissolved
              hydrocarbons, sulfuric acid, chromium, zinc, phosphates, alkaline substances, and suspended solids.
                   The NORM deposits may also accumulate in gas-plant equipment, separation facilities, and pipe yards.
              In gas-plant equipment, the NORM deposits may accumulate from radon-222 (radon) gas progeny. The gas
              is dissolved in the organic petroleum fractions in the gas plant and partitioned mainly into the propane and
              ethane fractions by its solubility (Rogers & Associates, 1990). Components having the highest levels of NORM
              include reflux pumps, propane pumps and tanks, and other pumps and product lines. In separation facilities
              where the separation of water occurs onshore, water handling equipment can become contaminated with
              NORM. Heater treaters, water knockouts, liquid product tanks, separators, tubing and piping, water transfer
              pumps, and other produced-water handling equipment accumulate radium isotopes in the form of scale.
                   Onshore point source discharges will be subject to treatment by municipal and industrial facilities in
              compliance with Federal and State discharge permit requirements. The NPDES permits are issued on a
              facility-by-facility basis, limiting the quantities of contaminants in and the temperature of each facility's effluent.
              These limits reflect a site-by-site specific analysis of flushing- and mixing-zone rates of the receiving body and
              the indigenous population's ability to tolerate elevations of temperature and pollutant concentrations.
                   The ongoing operation of these onshore facilities used in support of the proposed actions is expected to
              result in some routine nonpoint source pollution. The facility's presence, along with access routes, alters the
              natural hydrology and geography of the area over time. The volume and rate of storm-water runoff will remain
              greater than before construction; saltwater intrusion may occur; and, with existing vegetation modified, greater
              erosion around the facility may take place.
                   Increases of nonpoint source pollution due to runoff at support facilities may contribute particulate matter,
              heavy metals, petroleum products, chemicals, and radionuclides (particularly from pipe yards) to local streams,
              estuaries, and bays, causing temporary elevations in pollutant and turbidity levels. Two major pollutants are
              contained in this runoff--suspended solids (organic and inorganic) from exposed soil at the site and
              contaminants such as heavy metals.











                 IV-7 8

                 (b) Vessel Usage of Navigation Channels

                      Vessel usage of navigation channels can cause impacts as a result of erosion of the channel bank from
                 vessel traffic, operational discharges from vessels within the channels, and maintenance dredging or new
                 dredging required in support of OCS onshore support vessel activity. Section IV.A.3.c.(3)(b) discusses expected
                 characteristics of operational discharges from service vessels. Quantities estimated to be discharged during the
                 35-year life of the proposed actions from all OCS Program service vessel traffic are found in Tables IV-12
                 through IV-14.
                      Once dredged, navigation channels can continue to cause impacts to adjacent wetlands by widening of the
                 channel. Johnson and Gosselink (1982) have shown that channels with high navigation usage in coastal
                 Louisiana widen about 1.5 mlyr more rapidly than channels with little usage. The contribution of the OCS
                 traffic under the OCS Program scenario is assumed to account for 12 percent of the vessel traffic in coastal
                 channels, and a corresponding proportional contribution to the overall channel widening prOblem. along the
                 coast
                      No new channels are projected to be dredged under the OCS Program scenario. As discussed in Section
                 IV.A.3.c.(3)(c), the amount of maintenance dredging that can be attributed to OCS operations cannot be
                 quantified at the current time. It is assumed that the navigation channels used by OCS vessel traffic (Table
                 IV-15) will be dredged every other year. It can be assumed that 12 percent of the maintenance dredging in
                 these channels can be attributed to OCS operations.
                      In the future, some deepening of navigation channels may occur as a result of the need for providing access
                 to service and supply bases for deeper draft vessels needed for deep-water operations (Section IVA3.c.(3)(c)).
                 Based on the locations of projected oil and gas resources under the OCS Program scenario and existing plans
                 by the U.S. Army Corps of Engineers to deepen existing channels, it is assumed that two navigation channels
                 will be deepened from 5.5 to 6.7 in (17-22 ft) to provide access to service bases for deep-draft service vessel
                 movement directly related to OCS program operations. These channels are projected to be located in coastal
                 Subarea W-1 near Corpus Christi, Texas, and at Subarea C-2 in Fourchon, Louisiana.

                 (c) OnshorelCoastal Disposal of Offshore Wastes

                      The issue of onshore waste disposal is more related to future OCS Program activities than to a specific sale
                 because it is the annual large quantities of such wastes brought onshore that presents the problem.
                      If OCS drilling and production wastes cannot meet the U.S. Environmental Protection Agency's NPDES
                 effluent limitations or if these limitations require zero offshore discharge, offshore operationa I wastes must be
                 transported to shore for onshore disposal. New proposed effluent limitations and their changes to current
                 disposal practices is discussed in Section IV.A.2.d.(5). If USEPA finalizes its proposed effluent limitations, these
                 limitations would greatly increase the amount of both drilling and production solid wastes brought onshore.
                 Wastes are either piped ashore or loaded on supply boats or barges and transported to sborebases. Once
                 onshore they may be loaded on trucks or other barges to reach a commercial facility. Onshore disposal
                 alternatives include landspreading, landspreading with dilution, burial with unrestricted site use, burial *in
                 plugged and abandoned wells, well injection, hydraulic fracturing, or injection into salt donies. Because of
                 NORM contamination, a large quantity of a variety of wastes are being temporary stored within drums in
                 Louisiana until a final disposal site can be approved.
                      Waste disposal is one of the most difficult problems expected to face the United States public in future
                 years. There is currently considerable concern in the Gulf region about OCS waste onshore disposal practices,
                 primarily because of known past impacts to land use and environmental damage near disposal sites.
                      'Section IV.A.3.c.(4). discusses documented damage from oilfield waste disposal, current regulations by
                 MMS relating to waste disposal, and discusses current efforts to resolve the disposal of NORM-contaminated
                 wastes.











                                                                                                                              IV-79

                Nonhazardous Oil-field Waste Facility Capacities

                    Most oil-field operational wastes, such as produced sands and drilling muds, generated by the Gulf of
                Mexico oil and gas industry are landfarmed or placed in landfills located at ofl-field waste commercial facilities,
                called nonhazardous off-field waste (NOW) sites. These sites are nonhazardous because of their exemption
                from hazardous waste regulations under RCRA (Section I.B.3.d.(3)(e)). Ofl-field waste disposal is regulated
                by the State of Louisiana who requires that most operational wastes be disposed of at NOW facilities permitted
                by the State of Louisiana, Department of Natural Resources (State regulations 29-b). An analysis was
                completed by the MMS regional staff to evaluate the capacity of such sofid-waste disposal facilities located
                along the Gulf Coast to handle future onshore waste disposal. The disposal in onshore landfills of common
                trash and debris generated from the OCS oil industry is discussed separately below.
                    The MMS analysis relied heavily upon an assessment prepared for the USEPA by ERCE as part of their
                regulatory analysis for their effluent limitation regulations (USEPA, 1991). The USEPA considered eight NOW
                facilities in operation at the time; three more disposal sites permitted to receive oil and gas wastes but not yet
                receiving such wastes; and five hazardous waste disposal sites that they felt could accept nonhazardous oil-field
                wastes. The USEPA analysis only addressed the disposal of offshore drilling wastes. The ERCE report
                (ERCE, 1991) concluded that there will be adequate capacity at Gulf region commercial facilities to handle
                estimated volumes of drilling wastes requiring onshore disposal (projections through the year 1995). The report
                did not account for the use of these landfills by other industries or municipalities, did not account for
                production wastes and trash and debris disposal needs, and considered no dewatering of the wastes prior to
                landfarming.
                    The MMS analysis did not include the capacities of hazardous waste facilities located in the Gulf region
                in their total capacity estimate because the State of Louisiana felt these facilities would be unsuitable and too
                costly for oil and gas wastes disposal. The MMS analysis did include the disposal of all projected OCS-
                generated production solids at NOW sites, although no attempt was made to account for that portion of solids
                contaminated with NORM and therefore rejected by NOW sites. Thus, estimates of volumes of production
                wastes are conservative and likely larger than the volumes that will be received at NOW sites. Drilling muds
                were expected to be dewatered by 50 percent prior to disposal by landfarming or landfill.
                    Telephone conversations were made to the largest facilities identified in the State of Louisiana Approved
                Commercial Facilities NOW Site listing, and the listing of facilities from the USEPA analysis were modified
                to account for more recent information regarding capacities and number of NOW facilities. As of January
                1992, there are six NOW facilities in operation (3 facilities were consolidated) and three not in operation but
                having disposal capabilities, with a total capacity of 43.11 MMbbl per year. Of the nine commercial facilities
                handling drilling muds and cuttings for the Gulf OCS oil industry, three dispose of the waste by landfills and
                six by waste treatment and landfarming. Of these, one also has incineration activities and one uses wells for
                some disposal.
                    Through conversations with the largest facility (Brazzel, personal comm., 1992), it was learned that about
                25 percent of the total volume of oil-field wastes received at the facility was attributable to the OCS off and
                gas industry. Applying this 25 percent to all NOW site capacities reduces the total NOW site waste disposal
                capacity available for future OCS solid-waste disposal to 10.8 MMbbI per year.
                    The total volume of dewatered drilling muds and produced sands requiring onshore disposal and generated
                from activities associated with total OCS Program activities is calculated from Table IV-14 and totals 14.93
                MMbbI during the next 35 years, which averages about 0.427 MMbbl per year. Although not included in the
                table, if 18 percent of drill cuttings are also brought onshore (Jordan, personal comm., 1992), this number can
                increase to 0.586 MMbbl per year.
                    It is noted that this analysis does not consider one type of OCS waste brought to NOW facilities--
                production storage tank sludges--primarfly because no future estimates are available. However, it is assumed
                that tank sludges are a very small portion of the total wastes disposed of onshore, and this omission is not
                expected to greatly change the estimated total volume of solid-wastes to be disposed of onshore in the future.
                    Comparing the known Gulf Coast capacity for OCS solid-waste disposal (10.8 MMbbl/year) to the
                estimated total OCS Program volume of these wastes (0.586 MMbbl/yr) indicates that there is excess capacity
                at Gulf Coast commercial facilities for receipt of future operational wastes.











                 IV-80

                 Municipal Landfill Capacity

                     Trash and debris, as defined above, are not allowed to be disposed of at NOW facilities, according to State
                 of Louisiana regulations. Discussion with industry shows that these wastes are disposed of at municipal landfills
                 largely located in the coastal zone. At present, there is no estimate of the volumes of trash and debris being
                 brought onshore for disposal. Without such estimates, it is difficult to determine if future disposal will exceed
                 landfill capacity. Given the uncertainties, but being aware of the problem with landfills in general, it is assumed
                 that one landfill will need to be developed to receive OCS trash and debris generated froni all future OCS
                 Program activities. This landfill will be built in the Louisiana coastal zone but not in any wetlands.
                     The creation of one landfill is not expected to result in adverse effects to public services and community
                 infrastructure. It may, however, result in emotional stress to those persons living in proidnifty to the new
                 landfill sites. The disposal of offshore wastes would, in this case, result in adverse impacts to social patterns
                 in a limited area near the newly created landfills. This adverse effect could be mitigated by properly planning
                 future landfill locations.
                     The following discussions provide further information on specific types of OCS offshore operational wastes
                 disposed of in onshore areas.

                 Produced Waters

                     Realizing that USEPA!s effluent limitationsregulations are not finalized nor that industry has complied with
                 the State of Louisiana's new regulations, this document assumes that these regulations will be successful in
                 limiting the quantities of produced waters discharged into coastal surface waters. It is assumed that there will
                 not be any OCS produced waters shipped onshore and discharged into inland surface waters after the year
                 1997.
                     Although not discharged into surface waters, about 20 percent of OCS produced waters generated as a
                 result of future OCS Program oil and gas production will continue to be piped onshore to Louisiana for
                 disposal (2,439 MMbbl) (Table IV-12). Disposal methods will be very different from past practices. This
                 projection is based on the future operating status of the 15 largest, existing coastal OCS produced-water
                 separation facilities. The locations of some of these OCS coastal separation facilities are on barrier islands or
                 in State nearshore, open waters; and in areas near the shoreline, as in Pass Fourchon. These facilities either
                 receive produced waters mixed with oil from a number of pipeline systems serving a number of fields and
                 operators or they are field specific. For instance, the Fourchon terminal receives produced waters from 20
                 blocks. These multi-field facilities all gave some indication that they hoped to receive produced waters from
                 new leases in deeper waters. The facilities receiving waters from a number of systents are upgrading,
                 expanding, and/or centralizing their processing components. Most are improving their pit systems and changing
                 their discharge points as the result of consultations with the State of Louisiana. Two of these sites, the Grand
                 Isle and Sabine Pass separation facilities, will inject future produced waters into wells. The Pass Fourchon and
                 Timbalier Island multi-field facilities will continue to operate but will ship the separated produced waters back
                 out to OCS waters. Four of the 15 facilities do not, at present, fall under the criteria for prohibition as outlined
                 by the State of Louisiana (one discharges into open waters and three into the Mississippi River or its passes).
                 Two facilities are shutting down. Seven of the 15 major separation facilities only receive produced waters
                 transported from one or two large fields leased by one operator and usually located in waters near the 3-mi
                 State boundary. These facilities would not receive produced waters from future leases but are included in this
                 analysis because they will continue to discharge produced waters from future oil production from the existing
                 leases until the fields are depleted.

                 Production and Dfilling Solids

                     It is projected that 18 percent of drilling muds and cuttings generated during drilling operations associated
                 with future OCS Program drilling activities will be shipped onshore for disposal. This is based on the following
                 assumptions: (1) oil-based drilling muds will be used when drilling wells beyond 10,ODO in depth; (2)
                 exploration and delineation wells will be drilled to an average of 13,500 ft-, (3) all oil-based muds will be











                                                                                                                             IV-81

                shipped onshore; and (4) the proposed effluent limitations preferred options will be finalized, therefore, an
                muds generated within 4 mi from shore will be shipped onshore. Total quantities of drilling muds and cuttings,
                disposed of onshore are provided in Tables IV-12, IV-13, and IV-14.
                    It is projected that 100 percent of production solids will be disposed of onshore. This projection is based
                on USEPA's proposed effluent limitation for produced sands is zero offshore discharge.                     Section
                IV.A.2.d.(5)(d) discusses produced solids in more detail. Because of NORM contamination of these solids,
                many of the solids have been temporarily stored in drums at service bases until an approved disposal site can
                be found.


                Production Equipment

                    Not all scale is removed from equipment and disposed of with produced sands. Scale is a hard, rock-like
                flow restrictive substance that may form and adhere to downhole tubulars and in association with above-ground
                processing and transparent equipment and piping. As wells and facilities reach the end of their economic life,
                plugging and abandonment procedures are performed on the wells, and the production facilities are removed.
                Pipes removed from the wells and the process equipment may have accumulations of scales within. These
                scales may contain Ra-226 and Ra-228 in concentrations averaging 0.1-2,800 picoCuries per gram (pCi/g).
                Some of these levels have been measured as high as 100,000 pCi/g. Presently, such accumulations prohibit the
                sale of this equipment either as scrap metal or for reuse in ways other than which they were originally intended.
                Therefore, these tubular goods must be cleaned to remove the contaminants before the transfer of ownership.
                Once removed, the contaminated wastes are returned to the operators for appropriate disposal. Because of
                the cost involved in contaminant removal, many operators have elected to stockpile the tubulars and process
                vessels at operator-owned facilities or NOW sites until a cost-effective method of radioactive scale removal is
                found. Although no estimate of the number of pipe stored onshore from OCS Program operations is available,
                some minor impacts to land use from this operation are expected to occur.

                Other Solid-wastes

                    Besides drilling and production wastes, the State of Louisiana has expressed concern for the transport to
                shore of other types of solid-wastes, such as mud bags, drums, crates, and a variety of domestic wastes that
                often are disposed of at municipal landfills.
                    Regarding the trash and debris subcomponent of solid-wastes, MMS has been very active in promoting
                industry reduction. We issued NTL 86-11, Guidelinesfor Reducing or Eliminating Rash, recommending that
                operators and their contractors and subcontractors develop and implement proper trash handling education
                and training programs. The NTL also recommended reduction and compaction for all waste materials sent
                to onshore disposal sites. In May 1990, MMS contacted all lessees and operators, strongly encouraging use of
                large containers/bulk storage offshore. Recent evidence available from industry indicates a widespread
                cooperation with our recommendations.

                (d) OnshorelCoastal Spills

                    The impact from oil spills associated with the OCS oil leasing program to the environmental resources
                identified in this document is one of the greatest concerns identified by the public. Although beyond the
                regulatory authority of MMS, spills can occur from onshore activities supporting the production of OCS oil and
                gas. Impacts from those spills are analyzed in Section IV.D. These spills are most likely to occur at coastal or
                onshore storage and processing facilities, particularly at the terminal transfer points and from coastal pipelines
                and barges moving OCS oil to processing facilities. Because MMS does not maintain records of these spills,
                the U.S. Coast Guard database on spills was used. This database does not distinguish the source of the spill
                incident, so projected onshore spill occurrences occurring from proposed action activities are estimates of the
                likely subset of the larger database. Assumptions of spills occurring from OCS Program onshore support
                operations occurring during the 35-year life of the proposed actions are provided in Section IV.C.1.











                 IV-82

                 2. State Oil and Gas Activities

                 a. Leasing, Production, and Associated Infrastructure
                     Comprehensive information on oil and gas activities in State offshore and coastal wateirs in the Gulf of
                 Mexico Region has not been compiled. Many activities carried out in State waters prior to the 1950's were
                 neither documented nor permitted in the way they are now, and information is scarce or lacking (Groat,
                 personal comm., 1984).
                     In Texas State offshore waters, accumulated oil and gas production through October 1989 was 22.2 MMbbI
                 of oil and 2,888 Bcf of wet gas (gas that includes condensate). Annual oil production peaked in 1977 at 2.6
                 MMbbl; whereas, annual gas production peaked in 1980 at 254 Bcf. Of the some 280 rigs operating within the
                 State, 15 were located in offshore waters and none were located in inland waters (Oil and Gas Journal, 1991).
                 In addition, no inland drilling barges were operating in Texas coastal waters at that time. Approximately 1.95
                 MMbbl/day of crude-pil and lease condensate are produced within the State (Oil and Gas Journal, 1991).
                     In Louisiana State offshore waters, accumulated off and gas production to January 1, 19&;, was 1.442 Bbbl
                 and 10,657 Bcf, respectively. Annual off production peaked at 72.1 MMbbl, whereas annual gas production
                 reached a peak of 604 Bcf in 1972 and thereafter steadily declined. The Louisiana Mineral Board conducts
                 lease sales monthly. Of the some 90 rigs operating within the State, 43 were located in offi;hore waters and
                 13 were located in State inland waters (Oil and Gas Journal, 1991). In addition, 29 inland drilling barges were
                 operating in Louisiana coastal waters at that time. Approximately one million barrels per day of crude oil and
                 lease condensate are produced within the State (Oil and Gas Journal, 1991).
                     The State of Mississippi has experienced a limited amount of offshore activity. Three (-exploratory wells
                 were drilled in the 1950's; all were dry holes, and the relevant leases have expired. In late August 1986, an
                 exploratory oil and gas well was drilled in Mississippi coastal waters 7 km (4.5 mi) south of Ship Island. Fifteen
                 days after drilling had begun, the drilling was terminated. Currently, 14 land-based rigs are operating in the
                 State, with no active leases in Mississippi State waters. Thirteen rigs are operating within State onshore areas
                 (Off and Gas Journal, 1990). Approximately 73,000 bbl/day of crude oil and lease condensate are produced
                 within the State (Oil and Gas Journal, 1991).
                     Oil and gas activity in the State of Alabama's offshore waters has increased over the past few years. The
                 Lower Mobile Bay Mary Ann Field was discovered in 1979. Since that, initial discovery, several others have
                 been made, confirming the commercial potential of natural gas in Mobile Bay. There are two producing fields
                 in Alabama State waters--the Lower Mobile Bay Mary Ann Field and the South East Mobile Bay Field. Of
                 approximately eight rigs operating within the State, three are located in offshore and inland waters (Oil and
                 Gas Journal, 1990). Approximately 49,000 bbl/day of crude oil and lease condensate are produced within the
                 State (Oil and Gas Journal, 1991).
                     The State of Florida has experienced a limited amount of drilling in State coastal waters. Between 1945
                 and 1983, 29 exploratory wells were drilled in waters under Florida jurisdiction at sites extending along the
                 entire Gulf Coast from Pensacola to the Keys and Dry Tortugas. None of these wells resulted in development
                 or production. Coastal Petroleum Company holds the only two active leases in Florida waters as of January
                 1989. These leases, which date back to the 1940's, are large in size and geographic coverage. Currently, there
                 is a moratorium on drilling activity in Florida State waters, and the State has no plans for lease sales in the
                 future. One rig is now operating within State onshore areas (Oil and Gas Journal, 1991),. Approximately
                 10,000 bbVday of crude oil and lease condensate are produced within the State (Oil and Gas Journal, 1991).

                 b. Related Concerns

                 (1) Drfflin&Related Wastes

                     In 1989, the Louisiana Department of Natural Resource estimated that approximately 13,000 oil-field waste
                 pits existed in the State. Other projections have been as high as 20,000. Traditionally, reserve pits associated
                 with onshore drilling operations consist of one large pit into which drilling muds and cuttings, wash water,











                                                                                                                             IV-83

               rainwater, and other liquid wastes are placed and stored until operations begin. Problems associated with
               managing these pits result from contaminated materials being introduced into uncontaminated materials,
               rendering the contents of the pit unsuitable for on-site treatment or disposal. Closed mud systems are often
               employed in situations where total haul-off of all drilling wastes is anticipated. Use of these systems reduces
               not only waste volumes, but disposal costs as well (Spell, 1990).
                   On-site pits are often used to handle categories of oil and gas wastes other than produced water, including
               drilling muds and associated oil-field wastes (fracking fluids, emulsifiers, workover fluids, biocides, mud
               additives, etc.). A number of problems have arisen from the use of these "multi-purpose" pits. As a result of
               poor pit design (improper lining and retaining wall construction) and management, many of these pits
               contaminate surrounding surface and groundwaters and adversely impact proximate wetland and agricultural
               areas. Unlined pits are banned in certain areas of some States because of high soil permeability and relatively
               shallow, unconfined groundwater. Closure of production pits containing oily materials requires dewatering and
               removal of oily sludges from pit bottoms. This material is then land-spread or buried on-site or taken to an
               off-site, licensed oil-field waste disposal site for burial. The remaining pit is filled and capped with clean soil
               graded to blend with the surrounding terrain. A recent concern involving oil-field waste pits was brought about
               by a U.S. Fish and Wildlife study that estimates that up to 500,000 animals, mostly waterfowl and migratory
               birds, are killed annually from landing in open waste pits (Hall, 1990). The solution to this problem is to cover
               the pits and tanks with mesh to prevent animals from entering. A number of states have enacted regulations
               or have developed guidelines for this approach.
                   Many oil-field wastes are transported via truck to adjacent parishes, counties, or even States for off-site
               storage and disposal. As with on-site disposal, disposal of such wastes is accomplished through a variety of
               methods, including reinjection, containment in surface impoundments, land application, landfill, and burial.
               Crawley and Branch (1990) suggest that land treatment has proven successful for treating organic wastes and
               conservative pollutants (heavy metals). However, a primary concern with this method is the potential for highly
               soluble salt concentrations to move out of the treatment zone. Impoundments are traditionally used for
               containment of these wastes. Subra (1990) reports that at one such disposal site in Vermilion Parish, Louisiana
               (designated Superfund site), 442 companies were identified by USEPA as being potentially responsible parties.
               Of these, 69 percent (approximately 305 companies) were from Louisiana, yet only 9 were located in the parish.
                   Improper storage or disposal of drums containing solvents, corrosion inhibitors, and biocides used in drilling
               operations also presents a potential for environmental problems. Likewise, the improper design and
               management of storage tanks at commercial oil-field disposal facilities poses the potential for causing adverse
               impacts to surrounding surface and ground waters and wetland areas.

               (2) Aroduction-Related Wastes

                   Boesch and Rabalais (1989a) indicated that, of the 2 MMbbI (434,772 bbl/day [BPD] from OCS activities)
               of produced waters discharged into Louisiana waters daily during 1986-1989, 23 percent was discharged into
               fresh marsh, 22 percent into brackish marsh, and 17 percent into salt marsh environments. The remaining 38
               percent was discharged into open embayments or nearshore Gulf waters. The largest number of discharges
               were located in the Terrebonne (199 discharge points) and Barataria (136 discharge points) estuarine systems.
               The largest aggregate volumes were reportedly discharged in Chandeleur Sound (416,000 BPD), the Mississippi
               River Delta (402,000 BPD), and Barataria Bay (363,000 BPD) estuarine systems (Figure IV-3). The report
               further estimated the total volume of produced waters discharged into Texas waters at 823,575 BPD, including
               87,721 BPD (11%) into those designated as "inland." The Texas Railroad Commission stated there were no
               discharges of OCS-generated produced waters in Texas coastal waters. By far the greatest volume of these
               waters were discharged into the Galveston-Trinity estuarine system (Figure IV-4). Within this estuary there
               were 208 discharge points that delivered an estimated 400,000 BPD. Matagorda-Lavaca and Corpus Christi-
               Nueces estuarine systems received substantial produced-water discharges from 32 discharge points
               (approximately 200,000 BPD) and 54 discharge points (approximately 60,000 BPD), respectively.










                 IV-84



                                      500
                                             -  SABN SABINE LAKE      MARC BAY MARCHAND  UND
                                                CALC CALCASIEU LAKE   CHND CHANDELEUR 30
                                                VERM VERMILION BAY    PONT UWE PONTCHARTRAIN
                                      400-      ATCH ATCHAFALAYA BAY  GULF GULF OF MEXICO
                                                TERR TERREBONNE BAY
                                                SARA BARATARIA MY
                                  C             MERM MERMENTAU RIVER BASIN
                                  cc  300-
                                  0


                                      200-




                                      100-




                                         0
                                             SABN CALC MERMVRML ATCH TERR SARA MARCCHND P014T GULF

                                  Figure IV-3. Distribution of Produced Water Discharges in Louisiana's
                                                   Estuarine Basins (Boesch and Rabalais, 1989a'

                                     400

                                                LMA LAGUNA MADRE
                                                CCH CORPUS CHRISTI SAY
                                                ARA ARANSAS SAY
                                                SAN SAN ANTONIO BAY
                                     300-       MAT MATAGORDA BAY
                                  (A
                                                COL COLORADO COASTAL BASIN
                                                BRA BRAZOS COASTAL BASIN
                                                GAL GALVESTON BAY
                                                SABN SABINE LAKJE
                                  0             GULF GULF OF ME)aC0
                                     200-





                                     100-





                                        0
                                             LMA CCH ARA SAN                MAT COL BRA            GAL SAB14 GULF
                                                                                                     X\






























                                     Figure IV-4. Distribution of Produced Water Discharges in Texas
                                                      Coastal Waters (Boesch and Rabalais, 1989a).











                                                                                                                            IV-85

                     Due to their high salinities, Gulf Coast produced waters are generally much denser than Louisiana inland
                waters. Boesch and Rabalais concluded that produced-water discharges can act as dense plumes after discharge
                into estuarine waters. Produced waters can contain various radionuclide and volatile and semivolatfle organic
                hydrocarboncontaminants. Boesch and Raba" demonstrated that producedwaters discharged into Louisiana
                waters contained high concentrations of petrogenic hydrocarbons, with sediments near these effluents
                contaminated with semivolatile organic hydrocarbons. Petroleum contamination was noted in sediments up
                to I kin from discharge sites. Reid surveyed several Louisiana produced water effluents and found radium 226
                levels ranging from 131 + 3 pCi/I to 393 + 7 pCi/L The natural radium 226 activity in Louisiana surface waters
                is below 1.0 pCi/1 and in Louisiana soils from less than 1.0 to 7.0 pCi/I (Louisiana Dept. of Environmental
                Quality, 1989). Some of these discharges have been found to contain high levels of toxic metals (vanadium,
                copper, and arsenic) and organics; these levels represent a significant negative impact to confined (poorly
                flushed) waterways. Because of the hydrology of such systems and the particle reactive nature of the metals
                and organics being discharged, it has been anticipated that these substances will continue to accumulate at high
                levels within sediments in proximity to the discharge (St P6, 1990). A more in-depth discussion of the
                characteristics and effects of produced-water discharges may be found in Sections IV.AA and 5. Three
                alternatives are employed for disposing of produced waters--injection into disposal wells (90% of U.S. produced
                waters are injected), storage in tanks, pits, and other containers, and discharge into surface waters. Louisiana
                DEQ reports indicate that 70 percent of the produced-water from oil-field operations in Louisiana is discharged
                into surface waters. As previously noted, on-site pits are commonly used to handle categories of oil-field wastes
                other than produced water, including drilling muds and associated oil-field wastes.
                     In March 1991, the Louisiana State Legislature approved regulations banning the discharge of all waste-
                water (primarily produced water) associated with oil and natural gas exploration and production activities. The
                State's effluent guideline standards have been amended such that there shall be no discharge of produced water
                into State waters after January 1, 1995, unless the discharge(s) is authorized in an approved elimination
                schedule or is in effluent limitation compliance. Produced water shall not be discharged within 1,300 ft of an
                active oyster lease, live natural oyster or molluscan reef, designated oyster seed bed, or seagrass bed.
                     Discarded oil-field equipment may pose a potential environmental threat to areas surrounding storage and
                cleaning sites, scrap-yards, and metal reclamation yards. Surfaces of production tubing, holding tanks,
                separators, heater treaters, and other like equipment may be contaminated with scale material. Scale restricts
                production, causes equipment inefficiency, and is costly and time-consuming to remove. Scale problems cost
                industry on the order of a billion dollars annually. Recently, another problem associated with scale formation
                has surfaced--radioactivity. The health risks and environmental consequences associated with the disposal of
                NORM-contaminated oil-field wastes are largely unknown at this time. A growing awareness of this problem
                was raised when reports surfaced of contaminated pipe being used to construct bleachers, school and public
                park playground equipment, and as work material in welding classes at schools. The NORM regulation and
                management is an issue of concern to both Federal and State governments and the oil and gas industry. A
                more detailed discussion of NORM may be found in Section IV.A.5.b.(5).
                3. Other Major Offshore Activities

                a. Ocean Dumping

                     All ocean dumping is regulated by the Marine Protection, Research, and Sanctuaries Act of 1972, as
                amended (33 U.S.C. 1401 et seq.). Regulations (40 CFR 220 et seq.) implementing the Act require a USEPA
                permit for all ocean dumping of industrial wastes and municipal sludge materials. The termination of ocean
                dumping of sewage sludge and industrial wastes by December 31, 1981, was mandated by 33 U.S.C. 1412a.
                The designated ocean areas in which wastes may be disposed are listed in 40 CFR 228. Further, USEPA has
                published an annual report entitled Ocean Dumping in the United States. This report includes information on
                permit holders, types of waste approved for disposal under the permit, and yearly waste volumes disposed.
                There are no designated deep-water disposal areas in the Gulf of Mexico.











                IV-86

                     The current interim designated Dredged Material Disposal Sites are now being converted by USEPA into
                formally-designated sites. These sites, used for the disposal of dredged material from the I J.S. Army Corps
                of Engineers channel-dredging programs, have, in most cases, been used for this purpose fDr as long as 25
                years.

                b. Deep-water Ports

                     The Deepwater Port Act of 1974 (33 U.S.C. 1501) gives DOT the authority to license deep-water ports.
                The purpose of a deep-water port is to provide offshore terminal facilities for offloading oil froni'tankers too
                large (typically supertankers with drafts greater than 40 ft and up to 700,WO dwt) for conventional ports and
                to transport the oil to shore via pipeline, thus avoiding the need for lightering. The Louisiana Offshore Oil
                Port (LOOP) is the only deep-water port in the Gulf. It is located in 35 ni (115 ft) of water in Grand Isle
                Block 59, approximately 30 kni (19 mi) from shore. Vessel access to LOOP is by means of the designated
                fairway and safety zone. No mobile drilling operations or installation of permanent structures may take place
                in these areas. An anchorage area is also designated in the vicinity of LOOP. Fixed and mobile structures may
                be placed in anchorages under certain spacing limitations. Fairways associated with LOOP Eire designated in
                33 CFR 166 (Shipping Safety Fairways). This information was published in the Federal Register on July 1, 1985
                (50 FR 28989).

                c. Non-energy Minerals Program in the Gulf of Mexico

                Sulftir Program in the Gulf of Mexico

                     Presently, there is sulphur produced from leases in Federal and State waters offshore Louisiana. Caminada
                Mine, owned by Freeport Sulphur Company, lies in Federal waters in Grand Isle Blocks 16, 17, 22, and 23.
                Production was first initiated in March 1969, with 90 sulphur wells, 7 bleedwater wells, and 1 brine well drilled
                to date. The produced sulphur is to be transported to the Grand Isle shore base by barge. The Caminada
                Mine consists of a power plant platform, a shop/warehouse platform, a living quarters/office platform, two
                production platforms, and a bleedwater/brine-well platform. Production at Caminada Mine is projected to
                continue until approximately 1999.
                     Main Pass Sulphur Mine, another Federal lease owned by Freeport McMoran and partners, lies in Main
                Pass Block 299. Drilling at Main Pass began in December 1988, with sulphur encountered in -19 of the 20 wells
                drilled. Transportation and shipments of sulphur from the mine are handled by the Port Sulphur terminal.
                Ten production platforms are expected for all drilling activities, with production of sulphur expected to begin
                January 1992. Recoverable reserves of 67 million long tons (MMLT) is anticipated so that the Main Pass
                Sulphur Mine should produce for 30 years or more.
                     Grand Isle Mine, also owned by Freeport Sulphur Company, lies in State waters in Grand Isle Blocks 9,
                10, 18, and 19. The Grand Isle Mine consists of 5 large platforms and 10 smaller ones connected by nearly
                a mile and a half of bridges. Ten test wells, 437 sulphur wells, 35 bleed wells, and 3 brine wells have been
                drilled at the Grand Isle Mine, with 97 more sulphur wells to be drilled in the future. The sulphur is
                transported by barge to Grand Isle, Louisiana. From the shore base at Grand Isle, the sulphur is transferred
                to the Port Sulphur terminal by barge.
                     The Frasch technique is used for the mining of sulphur. Heated seawater, injected into the: mineral-bearing
                formation, results in melting of the elemental sulphur. Air, pumped to the level of the molten sulphur, lifts
                the sulphur to the surface. A steam-heated generator discharges air and other gases in the sulphur to the
                atmosphere. Sulphur is subsequently collected in vessels known as "pans," where it is pumped to storage tanks
                and then to barges.











                                                                                                                           IV-87

              Other Mineral Progrants

                  On December 31, 1986, Secretary of the Interior Donald P. Hodel and the Governors of Alabama,
              Mississippi@ Louisiana, and Texas announced an agreement to establish a joint Federal/State task force to study
              the occurrence, location, and economic feasibility of developing marine mineral resources offshore the
              aforementioned states. The Task Force is jointly co-chaired by representatives from the Alabama Geological
              Survey, the Texas Bureau of Economic Geology, and MMS.
                  The Task Force spent a year developing an inventory of the publicly available geologic and geophysical
              data, identifying mineral commodities and the particular areas of potential commercial interest, and performing
              a preliminary economic feasibility study. A draft report was completed in November 1988, and a final report
              with recommendations for further action was submitted to the Secretary of the Interior and the Governors in
              March 1989. This report summarized the work of the Task Force, projected future work to be undertaken,
              and made recommendations on the engineering, environmental, and economic feasibility of mineral extraction
              on the OCS.
                  The Task Force currently is studying OCS sources of beach nourishment materials around Ship Shoal.
              Sand dredging in the Ship Shoal/Isles Dernieres area is being studied for beach replenishment and barrier
              island restoration. This is needed for coastal restoration and protection against the accelerating rate of
              wetlands loss in Louisiana.

              d. Marine Transportation

                  Vessels operating offshore often use the network of established safety fairways. Over the years, an extensive
              shipping pattern has developed among the major Gulf ports and between the ports and destinations outside
              the northern Gulf via the Straits of Florida, the Yucatan Channel, and the Bay of Campeche. As oil and gas
              development began to move offshore, the potential for conflicts between marine transportation and oil and gas
              activities increased.
                  Marine transportation is not projected to increase in future years, but it has fluctuated from year to year.
              Marine-transportation traffic can contribute to operational effors, which might result in oil spins, groundings
              or in collisions involving other vessels or fixed structures such as platforms and rigs. Section IV.B.6. discusses
              oil spins from marine transportation of both imported crude off and petroleum products.
                  Collisions may lead to pollution and possibly loss of lives and property. Records of vessel mishaps
              concerned with OCS operations show that 85 vessel mishaps occurred between 1960 and 1986, a 26-year period.
              Of these 85 events, 10 were noncontact events, that is, the vessel did not come into contact with an OCS
              structure or another vessel. Of the remaining 75 vessel mishaps, 46 (61%) resulted in minor property damage
              and 29 (39%) resulted in major property damage. Most of the vessel mishaps are the result of a service vessel
              (crewboat) bumping into the superstructure of a platform. Based on the descriptions in the MMS database
              on accidents (the Events File), 77 percent (58 vessel mishaps) were OCS vessels and 23 percent (17 mishaps)
              were non-OCS vessels. The 26-year record shows that an annual average of 1.5 vessel mishaps involve major
              property damage resulting from both OCS and non-OCS events Gulfwide. When OCS events are examined,
              less than one mishap (0.8%) occurs per year. Non-OCS events average about one vessel mishap every other
              year. Five accidents involving fatalities have occurred. Three of the five accidents were non-contact events, one
              involved no property damage, and the fifth (included in the figures above) resulted in major property damage.
                  The key mitigation factor for this problem was the establishment of a series of safety fairways and
              anchorages to provide unobstructed approach for vessels using U.S. ports. Fairways play an important role
              in the avoidance of collisions on the OCS, particularly in the case of the larger oceangoing vessels, but not an
              vessels stay within the fairways. Many vessels, such as fishing boats and vessels supporting offshore oil and gas
              operations, travel through areas with high concentrations of fixed structures. In such cases, the most important
              mitigation factor is the requirement for adequate marking and lighting of structures. After a structure has been
              in place for a while, it often becomes a landmark and an aid to navigation for vessels that operate in the area
              on a regular basis.











                  IV-88

                      There is a substantial amount of domestic waterborne commerce along the Gulf Coast that does not always
                  use open Gulf waters. Vessels engaged in this activity generally use the Gulf Intracoastal Waterway (GIWW@
                  which follows the coastline inshore and through bays and estuaries, and in some cases offshore from Fort
                  Myers, Florida, to Brownsville, Texas (Visuals Nos. I and 113).
                      The most significant contributions of marine transportation to cumulative impacts in the Gjulf are from the
                  tanker transport of imported crude oil. Extensive refinery capacity, easy port access, and a well-developed,
                  onshore-transportation system have contributed to the development of the Gulf Coast region as an important
                  center for handling imported oil and production from other domestic sources such as Alaska and California
                  (henceforth included in the category of imports). The area also includes the Nation's Strategic Petroleum
                  Reserve and LOOP, the only deep-water crude-oil terminal in the country (Section IV.13.3.).

                  e. Military Activities

                      The air space over the Gulf of Mexico is used extensively by DOD for conducting various air-to-air and
                  air-to-surface mission operations. A series of nine military warning areas and five water test areas are located
                  within the Gulf. These warning and water test areas are multiple-use areas, wherein military operations and
                  oil and gas development have coexisted without conflict for many years.
                      Utilization of offshore areas by DOD is provided for in 32 CFR 252. The DOD policy of joint usage and
                  coordination with DOI to ensure compatibility between agencies' programs is expressed within this regulation.
                      Military warning areas are established through the Federal Aviation Administration (FAA) Handbook
                  7400.213, Part 5, Chapter 15, which sets aside an air space area by the FAA for use by the military. The
                  military is not given a first use or a priority use of any area. The areas of military use are set aside so that the
                  FAA dan direct air traffic over or around them. The Federal Aviation Administration Handbook also refers
                  to an Executive Order that calls for coordination among the Departments of Transportation, State, and
                  Defense on the establishment and use of warning areas in international waters (international waters are
                  considered by the FAA as anything beyond the State/Federal boundaries). By the mechanisms through which
                  the military warning areas are established and maintained, DOD or any other agency cannot restrict the use
                  of a warning area. AJso, the mechanisms for the establishment of a warning area do not provide any means
                  for the area's enforcement. For all warning areas, the using agency, boundaries, and times of use are published
                  by the Defense Mapping Agency in the semiannual Department of Defense Flight Information Publication,
                  Special Use Airspace, North and South America.
                      The Eglin Water Test Areas were established by a letter of agreement among the Jacksonville Armament
                  Research and Test Center (ARTC), Houston ARTC, Miami ARTC, and Eglin Armament Division on April
                  26,1971.

                  Central Gulf of Merico

                      The Central Gulf has three warning areas that are used for military operations. They total approximately
                  4 million acres, or 7.6 peTcent@ of the water and air space of the sale area. The portions of the Eglin Water
                  Test Areas comprise another 4 million acres, or 7.3 percent, of the Central Gulf.

                           Wamine Areas                                 Defense OMrations Conducted

                           W-92                                         Air-to-air gunnery, rocket firing, sonar buoy
                                                                        operations

                           W453                                         Air National Guard training

                           W-155                                        Carrier operations, carrier pilot training

                           E'*7A-1                                      Rocket and missile testing and research

                           EV,`TA-2                                     Rocket and missile testing and research











                                                                                                                            IV-89

                 Westem Gulf of Mexico

                     The Western Gulf has two warning areas that are used for military operations. They total approximately
                 12 million acres, or 33 percent, of the water and air space of the sale area. Proposed Alternative C excludes
                 a 340-block polygon (about 1.8 million acres) off Corpus Christi, Texas. (Section II.D.2.c. describes this
                 alternative.) This carrier operations area was deferred for Sale 141 in a November 1990 agreement between
                 the MMS and the Department of Navy.

                         Warning Areas                              Defense Operations Conducted
                         W-228                                      Carrier operations, air-to-air gunnery, rocket firing,
                                                                    aircraft operations, submarine operations

                         W-602                                      High-altitude training
                 4. Other Major Onshore/Coastal Activities

                 a. River Development and Flood Control Projects

                     In recent decades, alterations in the upstream hydrology of the rivers that drain into the northern Gulf of
                 Mexico have resulted in coastal impacts. Changes in the hydrology of the Mississippi River basin, in particular,
                 have caused declines in sedimentation rates along the coast and have contributed to marsh deterioration in the
                 coastal wetlands of Louisiana. Coastal wetlands appear to expand or diminish in areal extent according to the
                 amount of sediment available, and sedimentation can be a limiting factor controlling marsh growth. In a
                 natural system, overbank flooding is a mechanism of introducing sediment-laden waters into adjoiningwetlands.
                 Flood control levees on the lower Mississippi River and its distributaries have contributed to wetland loss in
                 the Gulf because levees eliminate regular episodes of overbank flooding and prevent the distribution of alluvial
                 sediments across the Mississippi River Delta. In pre-channelization times, the flow of the river was distributed
                 among several distributary channels that delivered sediment to the coast over a broad area during high river
                 stages. Today, sediment from the river is discharged to the coast only through the main channel of the river,
                 which discharges directly out into the deep waters of the continental slope and through the Atchafalaya system.
                     As an example of this effect, Bayou Lafourche, in coastal Subarea C-2, was cut off from the Mississippi
                 River as a result of levee construction shortly after the turn of the century. Cleveland et al. (1981) have used
                 simulation models to demonstrate that if sediment from the Mississippi River were reintroduced into the
                 Barataria basin, an area experiencing high rates of land loss and fed by Bayou Lafourche, the basin would
                 experience net wetland gain during the next century.
                     In addition, the construction of dams and reservoirs on upstream tributaries of the reservoir has trapped
                 much of the sediment load of the river prior to reaching the coast. The suspended sediment load of the
                 Mississippi River has decreased nearly 60 percent since the 1950's, largely as a result of dam and reservoir
                 construction upstream (Tuttle and Combe, 1981; Turner and Cahoon, 1987).
                     As part of the Cumulative Analysis, sediment deprivation will continue as a major impacting factor in
                 Louisiana during the period of analysis. Although the reintroduction of sediments to coastal areas has been
                 considered as a means of restoring wetlands in Louisiana, the great expense of these projects and the legal
                 problems associated with a reduction in flood protection that will result from altering the river's levees and
                 from discharging riverine waters across private property will prevent a sediment reintroduction plan from being
                 implemented in the near future. Furthermore, even if sediment from the Mississippi River were discharged
                 into coastal wetlands, the river is currently discharging less than half of its original sediment load.
                     Hydrologic alterations of river basins in the WPA have also been implicated as a factor affecting coastal
                 erosion in Texas.











                 IV-90

                 b. Submergence and Natural Subsidence of Wetlands

                     The submergence of coastal wetlands in the Gulf of Mexico region contributes to the wetland loss problems
                 of the region. If submergence occurs faster than the rate at which sedimentation and peat formation can build
                 the marsh surface upward, marsh survival is threatened by the waterlogging and ultimate flooding of the marsh.
                 The submergence rate that is critical for the survival of wetlands in different parts of the Gulf has not been
                 determined.
                     Submergence in the Gulf is occurring most rapidly along the coast of Louisiana. The submergence rate
                 in Louisiana has two components: the rate of eustatic sea-level rise and the rate at which the land itself is
                 subsiding beneath the sea. During this century, the eustatic rate of sea-level rise along the Louisiana coast has
                 been relatively constant at 2.3 mm/yr (23 cm/century), although the rate has varied from a sca-level decrease
                 of 3 mm/yr to a maximum increase of 10 mm/yr over decade-long periods (Turner and Cahoon, 1987).
                 Depending on local geologic conditions, the subsidence rate varies across coastal Louisiana from 3 to 10 mm/yr.
                 The primary natural processes responsible for land subsidence include geosynclinal downwarping, compaction,
                 dewatering, and the horizontal flow of recent sediments. Anthropogenic factors, such as fluid withdrawals from
                 oil and gas reservoirs, appear to have only a localized influence on subsidence directly above the reservoirs.
                 In coastal Louisiana, the total area of wetlands with a subsidence potential related to fluid withdrawals greater
                 than 10 cm is about 4W kM2 (Turner and Cahoon, 1987).
                     Submergence of wetlands is also considered a factor in the erosion of wetlands in Texas (White et al.,
                 1985). In addition to submergence associated with eustatic sea-level rise, submergence alonly the Texas coast
                 has been compounded in some, areas by human-induced land subsidence from groundwater withdrawals
                 (Ratzlaff, 1980) and natural compactional subsidence (Swanson and Thurlow, 1973).

                 c. Contributors to Coastal Water Quality Problems

                     Contaminants can be natural components of the marine environment--such as trace metals--that affect the
                 use of the water body only when they exceed certain levels. Others, such as synthetic organics, are
                 anthropogenic inputs whose presence alone is considered contamination because they serve no purpose in the
                 natural mechanisms of the ecological components. Parameters usually measured to determine water quality
                 degradation include salinity, biochemical oxygen demand (BOD), chemical oxygen demand, petroleum
                 hydrocarbons (oil and grease), total suspended solids, total dissolved solids, nutrient loadings, heavy and trace
                 metal concentrations, coliform bacteria, synthetic organics, tributyltins from marine paints, toxic substances and
                 hazardous wastes, radionuclides, toxins, and solid-wastes (trash).
                     Major point and nonpoint sources of contaminants occurring along the Gulf CA)ast include the
                 petrochemical industry-, hazardous waste sites and disposal facilities; agricultural and livestock farming; citrus
                 processors; chemical manufacturing industry operations; fossil fuel and nuclear power plant operations; pulp
                 and paper mill plants; silviculture; commercial and recreational fishing; municipal waste-water treatment and
                 individual septic-tank effluents; coastal maritime commerce activities, especially at ports; dredging of harbors,
                 docks, navigation channels, and pipeline canals; the USEPA dredged-material disposal-site program; and urban
                 expansion. The petrochemical industry operations include oil and gas exploration, development, and production
                 operations; pipeline transport; tanker and barge movement of both imported and domestic petroleum products
                 and crude oils; petroleum and petrochemical refinery and processing operations; and oil-field waste disposal.
                 These topics are discussed elsewhere in this document.
                     The discharge of sewage and wastes from boats and vessels in coastal waters may impact water quality by
                 increasing BOD locally and introducing pathogens into the water column. Although the Federal Water
                 Po'Hution Control Act requires recreational boats to be equipped with approved marine sanitation devices,
                 boats still discharge treated legally and untreated waste illegally into coastal waterbodies. Although the waste
                 water generated by recreational boats is small, the organics are concentrated and, therefore, the BOD levels
                 are much higher than that of raw or treated municipal sewage. When this occurs in poorly flushed waters, the
                 DO concentrations of the water may decrease. In the more temperate regions, these effects are exacerbated
                 due to increased boat traffic, higher water temperatures, and higher metabolism rates for marine organisms.












                                                                                                                           IV-91

             The addition of disease-carrying pathogens from fecal matter in boat sewage poses a potential problem with
             regards to human health impacts. Humans are put at risk from either contacting contaminated waters through
             swimming or eating shell fish taken from such waters. Bacteria, viruses, and other water-borne diseases can
             be attributed to sewage pollution.
                 Antifouling paints and coatings containing copper and organotin biocides are used to prevent the buildup
             of barnacles and other encrusting organisms on vessels and docks. Other toxic compounds such as mercury,
             arsenic, and PCB's are no longer used due to their extreme toxicity. By 1985, up to 30 percent of the vessels
             world-wide used tnbutyltin-containingantifouling paints. A 1987 survey found that 97 percent of the    ' tributyltin
             use was on vessels or boats less than 65 feet and that 93 percent of this was on recreational boats. The
             environmental impact of organotins as a group of compounds has been the subject of research and study for
             almost a decade. Much of the work has focused on the fate of tributyltin compounds in the marine
             environment Tnbutyltins are a class of organic tins used in antifouling paints. There are two classes of these
             paints--conventional or those that leach continuously and copolymer which are released to the aquatic
             environment at much slower rates. Due to the rapid leaching of these compounds, elevated levels of tributyltin
             and its breakdown products have been found in the water, sediments and organisms where there are high
             concentrations of vessels and more specifically, recreational boats.
                 Studies indicate organotin is highly toxic to marine and freshwater organisms at very low levels. Tributyltins
             have been reported to cause acute and chronic toxicity to marine organisms, especially in small crustaceans
             (zooplankton) and bivalves. Bacteria and phytoplankton bioaccumulate tributyltin at concentrations of 600 to
             30,000 times the exposure concentration, while bioaccumulation in bivalves has been reported up to 4,000 times
             the exposure concentration. Bivalves are extremely susceptible because of their ability to metabolize these
             compounds and they are found in nearly anoxic sediments that lack the bacterial species necessary to degrade
             these compounds.
                 Unlike copper, tributyltin in seawater degrades rapi0y with a half-life of 3-15 days (seawater). Within the
             water column, the primary means of degradation in the presence of light appears to be debutylation by
             planktonic algae, especially diatoms. While in the absence of light, degradation is primarily by bacteria.
             Tributyltins tend to concentrate in the surface microlayer and are found at higher levels than found in the
             subsurface. Once these compounds adsorb to particulate matter and sinks into the sediments, it tends to
             concentrate and slowly degrade.
                 Tributyltin paints are now regulated in the United States by the Organotin Antifouling Paint Control Act
             of 1988. The Act prohibits the use of certain antifouling paints containing organotin and the use of organotin
             compounds, purchased at retail, used to make paints. The Act prohibits the application of antifouling paints
             to vessels less than 25 in in length, with the following exceptions: the aluminum hull of a vessel less 25 in in
             length or the outboard motor or lower drive unit of a vessel less than 25 in in length. All antifouling paints
             must be certified by the Administrator of USEPA not to have a release rate of more than 4.0 micrograms per
             square centimeter per day.
             5. Activities Outside the Planning Areas Affecting Migratory Species

             a. Coastal and Marine Birds

             Endangered and 77treatened Species

                 The piping plover, whooping crane, and peregrine falcon are migratory species protected by the
             Endangered Species Act Although none of the threatened or endangered species inhabiting the Gulf crosses
             more than one OCS planning area (USDOC, NMFS, 1990b), their wide-ranging movements make them
             susceptible to a variety of adverse impacts from outside of the planning area. The activities impacting these
             species are the same as for nonendangered and nonthreatened birds.











                   IV-92

                   Nonendangered and Nonthreatened Species
                       Populations of the three major types of Gulf of Mexico coastal and marine birds--waterfowl, wading birds,
                   and shorebirds--are augmented by seasonal migrants. All North American migrating birds lend to use specific
                   flight corridors to reach the Gulf of Mexico; the Central or Mississippi Flyway is the co)rridor of greatest
                   importance. Migrating waterfowl and wading birds reach the Gulf from south-central Canada and north-central
                   United States. Migrating shorebirds reach the Gulf from as far away as the Arctic Circle. Migrating coastal
                   and marine birds may continue migration into Central and South America or may exhibit a limited degree of
                   coastal movement within their terminal locality. Migrating coastal and marine birds do not cross planning areas
                   within the Gulf.of Mexico; however, they could be affected by activities outside the planning areas.
                       All three types of migratory species have experienced decreases in population (National Geographic
                   Society, 1983a; USDOI, FWS, 1988). 'Me loss and degradation of nesting habitat in the north-central United
                   States and south-central Canada from encroaching agriculture and drought may reduce p:)pulations of over-
                   wintering migrant waterfowl. The loss and degradation of Gulf wetlands as feeding and resting habitats may
                   reduce populations of migratory wading birds. Disturbances to and loss of barrier islands and beaches may
                   adversely affect populations of migratory shorebirds.
                       The storage of oily industrial waste in open pits within five southwestern states may seriously deplete
                   populations of birds migrating to the Gulf Coast. Migrating waterfowl are especially susce- tible because they
                                                                                                                P
                   apparently mistake the reflection of uncovered off pits and tanks for freshwater. Activities connected with State
                   oil and gas production within Gulf Coastal marshes or nearshore during the winter have the greatest potential
                   to damage populations of migratory coastal and marine birds.

                   b. Marine Turtles

                       iMarine turtles are exposed to adverse impacts throughout the Atlantic Northern Hemisphere because of
                   their pan-oceanic distribution and wide-ranging movements. These impacts include the activities associated
                   with OCS off and gas exploration and development described in the Base Case Analysis (Section IV.D.) and
                   a wide variety of other activities. In general, the projected level of development in the Central and Western
                   Gulf will decrease because of declining resource estimates. However, oil and gas exploration and development
                   will advance into deeper water, resulting in less activity in areas frequented by all but the leatherback turtle.
                   The explosive removal of platforms will increase nearshore, but the implementation of procedures for the
                   protection of sea turtles is assumed to avoid harassment or injury. Development in the Eastern Gulf and
                   Atlantic is expected to proceed slowly because of the absence of an oil and gas infrastructure and the lack of
                   public support. A consequence of slow development in these areas is a minimal impact on marine turtles.
                   Marine turtles are adversely impacted by oil spills from foreign oil transported by tanker to the Gulf,
                   production from State waters, and OCS production. The OSRA data indicate that foreign oil tankered to the
                   Gulf is the source of most spillage.
                       The major activities outside the planning areas that affect marine turtles include habitat loss and direct
                   mortality from dredging; pollutant discharge; commercial fishing; hopper dredge activities; nearshore boat
                   traffic; human consumption; contact with foreign, inshore, or processed oil; and ingestion of or entanglement
                   in anthropogenic debris (NRC, 1990). Dredge and fill activities occur throughout the nearshore areas of the
                   United States. They range in scope from propeller dredging by recreational boats to large-scale navigation
                   dredging and fill for land reclamation. Pollution resulting in loss of coastal aquatic vegetation is discussed in
                   Sections IV.D.La.(1) and IV.D.2.a.(I). The causes of aquatic vegetation loss include the alteration of salinity,
                   as in Florida Bay, as wen as man-induced increases in turbidity witnessed in Tampa Bay. Disturbances to
                   nesting beaches occur from a variety of sources, including construction, vehicle traffic, and deprivation of sand.
                   A more extensive discussion of the factors impacting barrier island beaches can be found in Sections
                   IV.D.l.a.(I) and IV.D.2.a.(1). Natural catastrophes, including storms, floods, droughts, and hurricanes
                   (Continental Shelf Associates, 1987), can result in substantial damage to sea turtle habitat. Drowning that
                   results from entanglement in commercial fishing gear has a significant impact on sea turtle populations. Shrimp
                   trawling in the southeastern United States has received extensive scrutiny because of its incidental turtle catch











                                                                                                                               IV-93
                (Center for Environmental Education, undated). Ile National Research Council (1990) has identified shrimp
                trawling as the greatest cause of human-induced mortality in sea turtles. The use of Turtle Excluder Devices
                is legislatively mandated in order to decrease losses. Unknown numbers of turtles also drown in driftnet and
                long-line fisheries.
                    Dismemberment of turtles by hopper dredging has resulted in turtle mortalities. Specific dredging projects
                include the Canaveral Ship Channel in Florida, the King's Bay Submarine Channel in Georgia, and channel
                dredging of ports throughout the Gulf. Data from the Sea Turtle Stranding Network indicate a large number
                of turtles are hit by boats. Although some of the records may include turtles already dead before being struck,
                boat traffic is considered to have a substantial impact (Teas, personal comm., 1989). The inshore and
                nearshore distribution of most sea turtle species, the locations of the strandings, and the composition of the
                boating traffic suggest that most collisions that occur in the Gulf are a result of recreational boating in Florida.
                The human consumption of turtle eggs, meat, or by-products occurs worldwide (Mack and Duplaix, 1979; Cato
                et al., 1978). Human use is probably substantial, but the frequently illegal nature of the activity suggests
                unreliable estimates of mortality. Marine debris is discussed in the Base Case Analysis. In addition to the
                incremental amount of trash and debris generated by the OCS program, trash and debris find their way into
                the marine environment from South and Central America, Europe, and North Africa. The volume of marine
                debris from these sources is unknown, as is its impact on sea turtles (USDOC, NMFS, 1989a; Heneman and
                the Center for Environmental Education, 1988).

                c. Cetaceans

                    Great whales and several species of smaller cetaceans are susceptible to adverse impacts from OCS oil and
                gas exploration and development and other activities in the Gulf, Caribbean and Atlantic because of their wide-
                ranging movements. In general, the projected level of development will be less than the year of greatest OCS
                oil and gas activity, 1972. Existing oil and gas activities in the Atlantic and Eastern Gulf are minimal and are
                not expected to become extensive. Development in the Central and Western Gulf is not expected to increase
                significantly over present levels. However, the move toward exploration and development in deeper water
                could result in more interactions with marine mammals. The effects of oil contact or oil ingestion are discussed
                in Sections IV.D.La.(5)(a) and IV.D.2.a.(5)(a). The OSRA data indicate that foreign oil tankered to the Gulf
                is the source of most spills.
                    Commercial fishing, maritime commerce, toxins that accumulate through the food chain, and whale
                watching are other sources of adverse impacts (Tucker & Associates, Inc., 1990). Entanglement in commercial
                fishing gear can result in the death or injury of marine mammals. Limited commercial or subsistence whaling
                also results in some whale mortality-, however, the small number of individuals affected and the infrequency
                of the interaction suggest that the impact is low. Maritime commerce can cause a variety of impacts, including
                collisions, noise disturbance, and marine pollution. Conflicts are most likely at the convergence of shipping
                lanes and migration routes, such as the Florida and Yucatan Straits and the migration routes of the Eastern
                Seaboard. The concentration of toxins through the food chain has been found in marine mammals. These
                toxins include hydrocarbon and heavy metal compounds from a multitude of sources including oil spills, ocean
                dumping, industrial and municipal effluents, and agricultural runoff. Sources of marine pollution are worldwide.
                Recreational whale-watching cruise vessels can disturb or collide with whales (Freeman, 1991). Although these
                activities are not popular in the Gulf, they do occur on the Eastern Seaboard.

                d. Fish Resources

                    Those nonestuary-dependentspecies of fish that are commercially important, such as mackerel, cobia, and
                crevalle, are called coastal pelagics. These species are distributed and spawn over a large geographic area and
                depth range within the Gulf of Mexico; they range throughout the Gulf and move seasonally (Gulf of Mexico
                Fishery Management Council, 1985). In general, pelagic populations exhibit some degree of coastal movement
                restricted to the Gulf of Mexico. This movement is not considered oceanic migration, as is the case with
                salmon. The coastal movements of these species are related to reproductive activity, seasonal changes in water











                IV-94

                temperature, or other oceanographic conditions. However, coastal pelagics could be affected by activities
                outside the planning areas.
                     Competition between large numbers of commercial fishermen, between commercial operations employing
                different fishing methods, and between commercial and recreational fishermen for a given fishery resource, as
                well as natural phenomena such as weather, hypoxia, and red tides, may reduce standing populations of coastal
                pelagics. Fishing techniques such as trawling, gill netting, or purse seining, when practiced nonselectively, may
                reduce the standing stocks of the desired target species as well as significantly affect other species. Hurricanes
                may change physical characteristics of offshore ecosystems used by coastal pelagics (Continental Shelf
                Associates, 1987).
                     The majority of commercial species, including coastal pelagics, harvested from the Gulf of Mexico are
                believed to be in serious decline from overfishing. Continued fishing at the present levels may result in rapid
                declines in commercial landings and eventual failure of certain fisheries. Commercial landings of traditional
                fisheries, such as shrimp, red snapper, and spiny lobster, have declined over the past decade despite substantial
                increases in fishing effort. Commercial landings of recent fisheries, such as shark, black drum, and tuna, have
                increased exponentially over the past five years. Those fisheries are thought to be in danger of collapse
                (Angelovic, written comm., 1989; USDOC, NMFS, 1991a).
                     Oil spills that occur within the Gulf of Mexico when high concentrations of fish eggs and larvae are present
                have the greatest potential to damage populations of coastal pelagic species. Therefore, those activities
                connected with nearshore State oil and gas production and foreign and domestic oil tanker movements
                throughout the Gulf may adversely affect coastal pelagic species.
                6. Major Sources of Oil Contamination in the Gulf of Mexico

                     Petroleum hydrocarbon contamination of the Gulf of Mexico is occurring from a number of offshore,
                coastal, and land-based sources. Major sources of petroleum hydrocarbons into Gulf waters include natural
                seeps; offshore and coastal off production activities; atmospheric inputs; marine transportation (especially
                tanker operations); coastal, municipal, and industrial wastes; and urban and river runoff. The presence of
                petroleum hydrocarbons in the marine environment is, to some extent, unavoidable. Hydrocarbons measured
                in Gulf waters have been identified as generated by both natural, geochemical processes and by anthropogenic
                inputs (pyrogenic and petrogenic). Although the Gulf comprises one of the world's most prolific offshore
                oil-producing provinces, onshore sources of hydrocarbons to Gulf waters far outweigh the contributions from
                offshore domestic production of oil.
                     While large spills capture the public attention and can cause serious short-term detriment2d effects, chronic,
                low-level inputs of petroleum hydrocarbons represent the greatest source of petroleum conlamination to the
                Gulf of Mexico. Major sources of such discharges include operational discharges from tankers while at sea,
                natural seepage, and coastal, municipal, and industrial discharges and runoff.
                     An examination of all major sources of oil contamination in the Gulf puts into perspective. the relationship
                between petroleum loadings to Gulf waters from federally supervised oil-production activities and from other
                anthropogenic sources and compares the relative contribution of OCS operations to other sources of petroleum
                in Gulf waters. It is important to understand that this exercise provides only order of magnitude rough
                estimates. There are major problems associated with any attempt to establish values for the inputs and flux
                of petroleum into the Gulf. The approach taken here is to use the concepts, assumptions, and estimates
                developed by the National Academy of Sciences (NRC, 1985) and to apply them to Gulf of Mexico values,
                when appropriate. Furthermore, the contribution from petroleum sources in Mexico and Cuba was not
                calculated.


                a. Other Sources of Oil Spills

                     The MMS database on spills from OCS operations (USDOI, MMS, 1991d) shows that the contribution
                from spills from OCS oil exploration, development, and production operations during the years 1964-1989 has











                                                                                                                              IV-95
               been 371,040 bbl of oil, condensation, diesel, and other off-contaminated materials. This is an average of 14,
               271 bbl per year, or 0.002 million metric tons annually (Mta).
                   Besides OCS-related spills, spills entering Gulf waters can occur from State oil and gas development in
               offshore and coastal waters; from other types of marine transportation, especially the importation and coastwise
               transport of petroleum products and crude oil; and from non-OCS-related onshore oil processing and storage
               facilities such as refineries and storage tanks.
                   The following estimates of future spill occurrence was formulated from two primary data sources: the U.S.
               Coast Guard's database on spill incidents in all navigable waters maintained in a national computerized
               database (USDOT, CG, 1989) and the Minerals Management Services' Environmental Policy and Programs
               Division, Washington, D.C., database on crude oil and petroleum product spills greater than 1,000 bbls from
               worldwide tanker operations. These databases were supported often by personal communication with a
               number of individuals dealing with off-spill incidents in the Gulf of Mexico area.
                   The following observations can be made after examining U.S. Coast Guard spill data for the entire U.S.
               waters. Locations of the spills kept in this database include open sheltered waters, river channels, ports and
               harbors, territorial seas, contiguous zone, and high seas. For the years 1984-1986, river channels had the most
               number of occurrences and the largest spills. This observation held true also for the Gulf region. Types of
               oil include both crude oil and petroleum products and can even include vegetable oils used in cooking. In
               general, crude off spills are the most common occurrence followed closely by diesel and fuel oil spills. Sources
               of spills include marine vessels, land vehicles, non-transportationactivities (refineries, bulk storage, onshore and
               offshore production), and marine terminals. Ile data show that non-transportation facilities underwent the
               most spill incidents during 1984-1986, while marine vessels and terminals spilled the largest volumes averaged
               over a year.

               Small Spills

                   Much of the U.S. Coast Guard's data are not broken down for the Gulf of Mexico area. The following
               information about small spills in the Gulf is either derived from the above USCG reports or from personal
               communication with the USCG. In the Gulf area, there were about 1,484 small spills occurring per year. The
               offloading and onloading of oil during transfer operations result in many minor spills. Conversations with the
               U.S. Coast Guard indicate that the major cause of spills less than I bbl in the Louisiana coastal and offshore
               areas is transfer operations (Westcott, personal comm., 1989). In 1988, the U.S. Coast Guard reported that
               the current discharge rate for oil during transfer operations is approximately 7.7 spills per 1,000 transfers (Oil
               Spill Intelligence Report, 1988). About four spills per year occur from transfer operations, the vast majority
               of these spills being less than 50 bbI (OR Spill Intelligence Report, 1988; Westcott, personal comm., 1989).
                   The projected annual number of small (less than 1,000 bbl) crude oil and petroleum product spills
               occurring in the CPA and WPA during the 35-year life of the proposed actions are 670 and 500, respectively.
               The great majority of these spills will occur in the coastal states bordering the Gulf. In the CPA Area, almost
               all of the spills will occur in Louisiana's coastal zone. The greatest majority of these spills will occur in the
               coastal states bordering the Gulf. In the CPA, almost all of the spills will occur in Louisiana's Coastal zone.

               La?ge Spills from Tankers and Barges

                   The catastrophic oil spill and the detrimental effects that resulted from the Exxon Valdez accident in Alaska
               have increased the public's perception of the risks associated with off-tankering activities. Major causes of
               worldwide tanker spills have included the following (in order of frequency): groundings, 32.6 percent; collisions,
               24.4 percent; contacts, 18.6 percent; oil transfer operations, 8.3 percent; fire and explosions, 7.9 percent;
               weather, 6.2 percent; and mechanical problems, 2 percent (Bao-Kang, 1987). (Collision means the striking of
               two ships; contact means the striking of an external object by a ship.)











                 IV-96

                 Import Tanker Spills

                      The import tanker spill rates for spills 1,000 bbl or greater are as follows: at sea, 0.45; and near port, 0.40.
                 The import tankering spill rate (at sea in the Gulf) is one-half the worldwide tanker spill rate (at sea) and is
                 based on the assumption that 50 percent of the spills related to import tankering will occur on the inbound
                 portion of the journey in the Gulf of Mexico study area.
                      The following provides projections of future large spills from import tankers occurring over the 35-year life
                 of the proposed actions:

                      It is estimated that 37 large offshore crude oil spills with a median size of 22,728 bbl are estimated to occur
                 from import tankering activities. Also, 21 petroleum product spills of 11,000 bbl are estimated to occur from
                 import tanker activities in the Gulf, mainly in restricted waters.

                           -   Information on large offshore crude oil spills from import tankering contactwith
                               environmentally sensitive resources were analyzed by the Mineral Management
                               Service's OSRA model. Table IV-21 and IV-22 in Section IV.C. provides the
                               probabilities of one or more spills 1,000 bbl or greater and the estimated number
                               of spills (mean) for import tankers occurring and contacting land segments over the
                               life of the proposed actions within 10 days.

                           -   It is estimated that 16 crude oil spills of 7,665 bbl (median size) will occur from
                               import tankering activities in the coastal and nearshore areas of the Gulf of Mexico.

                           -   Spills occurring over the 35-year life of the proposed actions near major p:)rts
                               receiving imported crude oil are broken down by port area.

                                    Import Tanker Spill Occurrence (spills greater than or equal to 1,000 bbl)
                                             for Major Ports Receiving Crude Oil (35-year estimates)

                                                                         Mean No.                      Probability
                              Port                                       of Spills                     (percent)

                           Corpus Christi, Tey-                             1.70                          0.82
                           Freeport, Tex                                    0.43                          0.35
                           Galveston/Houston, Tex.                          3.91                          0.98
                           Port Arthur, Tex./
                           Lake Charles, La.                                2.92                          0.95
                           Miss. River Ports, La.                           2.66                          0.93
                           LOOP                                             3.47                          0.97
                           Pascagoula, Miss.                                1.32                          0.73
                           Mobile, Ala.                                     1.10                          0.10

                 Other 7ypes of Barge and Tanker Spills

                      Figure IV-5 shows the distribution of the 82 tanker and barge spins greater than 1,000 bbl that have
                 occurred in the Gulf region since 1974 (USDOI, MMS, 1991d). Thirty-four of these spills were crude oil and
                 48 were petroleum product. Thirty-five were from tankers and 47 were from barges. Louisiana has
                 experienced the majority of these spills, having had 18 crude oil spills and 19 petroleum product spills in its
                 coastal area. ne majority of these spills have occurred on the Mississippi River. Barge spills are estimated
                 to be about 1,500 bbl. The barge spill size is calculated from crude and barge spills that have occurred in the
                 Gulf of Mexico area since 1974. The average barge spill size is 6,000 bbl.









                                                                                Crude Oil


                                                                                Petroleum
                                                                                 Products



                          Texas

                                           . ..........


                        Louisiana


               U      Mississippi
               co
               6-
               0
               C        Alabama
               0


               0          Florida
               -j              10

                   Gulf of Mexico
                       OCS     MISM

                               0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40


                                                    Number of Spills
                               INAMM                                                I









            Figure IV-5- Location of oil Spills (greater than or equal to 1,000 bbl) from Barges and Tankers in or near the
                      Gulf of Mexico from 1974 to JuIY 1990 (USDOI, MMS, 1990, unpublished information).











                   IV-98

                       It is estimated that the coastwise movement of oil between ports or terminals may cause another 60 large
                   spills from barges (18 in the WPA and 42 in the CPA) whose average size is 5,000 bbl. Further, it is assumed
                   that 104 spills (44 in the WPA and 60 in the CPA) with an average size of 10,000 bbl may occur from the
                   movement of petroleum products in restricted waters of the Gulf.
                       In order to obtain a mass balance of oil in the Gulf of Mexico, the National Academy of Sciences estimates
                   for spills in the Gulf of Mexico were used. Oil spillage from tanker accidents accounted for only about 7
                   percent (Gulf of Mexico) to 20 percent (World Oceans) of the total oil pollution occurring due to tankering
                   (USDOC, NOAA, 1984; NRC, 1985). Given this, accidental spills of any size from tankers contributes about
                   0.004 Mta to the petroleum hydrocarbon contamination of the Gulf of Mexico.

                   b. Operational Discharges
                       While casualty spills, especially the grounding or sinking of tankers, capture the attention of the general
                   public and policy makers and can cause serious detrimental effects, operational discharges occurring from
                   marine-tanker transportation have accounted for most of the oil discharges from tai,kers in the pasi (NRC,
                   1985). Operational discharges are routine and intentional discharges during normal operating procedures, and
                   they are allowed by law (although some limitations imposed by regulation may be eximeded during the
                   discharge). Routine tank washing and ballasting operations make up most of the operational discharges
                   associated with tankering activities.
                       The National Academy of Sciences' (NRC, 1985) report estimates that total oil losses from barge and
                   tanker operations are much larger than what is accounted for by oil spillage. Total discharges of petroleum
                   to world waters range from 7.4 to 19.2 MMbbl per year, with a best estimate of 10.7 MMbbl per year, or 1.45
                   Mta. About one-half of this is attributed to operational discharges from oil tankers (about 5; MMbbl annually);
                   the remainder is attributed to bilge water and fuel off release from all ships (about 2.2 MMbbl annually)
                   (considered an operational discharge), terminal operations (about 150,000 bbl annually), dry-docking (about
                   222,000 bbl annually), and accidental spillage (about 3 MMbbl annually). If we assume the ratio of spills in
                   world waters to spills in Gulf waters (20:7) from transportation sources can be applied to the total contribution
                   of petroleum hydrocarbons from transportation sources in world waters, we can calculate the total contribution
                   from all transportation sources in Gulf of Mexico waters. Total discharges of petroleum from all transportation
                   sources, which are dominated by operational discharges from tankers, are projected to be 0.5 Mta.
                       Besides oil spills from OCS operations, oil may enter Gulf waters from OCS operational discharges of
                   produced waters. Produced water discharged (after treatment that removes the majority of the entrained oil
                   content) contains, on an average, 89 ppm oil content (USEPA, 1991). The projected amount of OCS produced
                   water discharged (Tables IV-12 and IV-13) was multiplied by the average amount of entrained oil (89 ppm)
                   to determine the contribution to the petroleum loading of Gulf waters from OCS discharged produced waters.
                   This calculation results in an estimate of 54,633 bbl annually, or 0.007 Mta, of petroleum hydrocarbons entering
                   Gulf waters from operational produced-water discharges associated with OCS production.

                   c. Other

                       The Mississippi River is the major source of petroleum contamination in the Gulf of Mexico, carrying large
                   quantities of petroleum hydrocarbons into Gulf waters. Gulf of Mexico sediment samples collected within a
                   broad crescent around the River reflect petroleum contamination from the river's discharge (Southwest
                   Research Institute, 1981; Brooks and Giammona, 1988). The NAS (NRC, 1985) states that 0.13 Mta of
                   hydrocarbons enter the world ocean from river runoff that drains the interior of the United States. Accounting
                   for the fact that the Mississippi River drains two-thirds of the U.S., petroleum hydrocarbons in the River's
                   discharge due to upriver drainage alone could be assumed to be approximately two-thirds of 0.13 Mta; i.e., it
                   could be estimated to be approximately 0.009 Mta. However, much of the hydrocarbon burden measured at
                   the mouth of the Mississippi River as it empties into the Gulf is due to coastal inputs. Urban runoff and
                   routine, low-level effluents from industry wastewaters and municipalities located along the river in the area near
                   the Gulf of Mexico contribute large quantities of petroleum hydrocarbons. These sources are accounted for
                   in the following estimates of inputs from other chronic, low-level sources.











                                                                                                                               IV-99



                    Man's extensive use of fossil fuels, as well as lack of recycling of discarded oils, is reflected in the large
               contributions of petroleum hydrocarbons found in municipal wastewaters and urban runoff. Significant amounts
               of petroleum hydrocarbons are deposited in urban areas from a variety of sources--asphaltic roads; the
               protective asphaltic coatings used for roofs, pipes, etc.; oil used in two-cycle engines, especially outboard boat
               motors; gas station runoff-, and unburned hydrocarbons in car exhaust. These sources are either directly flushed
               by rainfall and runoff into storm drains and into coastal waters or rivers or are weathered, broken down, and
               then dispersed. The Automotive Information Council recently estimated that 8.3 MMbbI (approximately 1.2
               Mta) of used motor oil is generated annually in the U.S. by do-it-yourselfers. They estimated that 60 percent
               of this is poured on the ground, thereby adding 5.7 MMbbl of oil to the urban environment annually (0.814
               Mta). Much of this discarded oil contributes to the petroleum loading found in municipal wastewaters and
               urban runoff. The NRC (1985) determined that municipal wastewaters and urban runoff contributes almost
               26 percent of petroleum contamination to the world ocean. To determine an estimate of the amount of
               petroleum entering the Gulf from urban runoff and municipal wastewaters, the NRC methodology was applied
               to Gulf of Mexico statistics. Using a Gulf of Mexico U.S. coastal population of 14.7 million people (USDOC,
               NOAA, 1990), calculations result in a rough estimate of 0.024 Mta and 0.005 Mta from U.S. municipal
               wastewaters and urban runoff, respectively.
                    Other major land-based sources of petroleum hydrocarbons in Gulf waters include refineries and other
               industry effluents. Coastal refineries in the Gulf area have a total design capacity of 3.1\105 Mta). Using a
               discharge rate for U.S. refineries of 0.005 kg/Mta capacity (NRC, 1985), the contribution of petroleum
               hydrocarbons from Gulf Coastal refineries is negligible (1.5 x 10-6 Mta). These discharges enter coastal rivers
               (particularly the Mississippi River) that drain into the Gulf or directly drain into coastal waters. The NRC did
               not provide a methodology for estimating the contribution of nonrefinery industrial wastes. The number they
               generated was based on an average from several data sources. If one assumes that such industries are evenly
               distributed in the U.S. coastal zone, and if the NRC's estimate of nonrefinery industrial waste input (0.2 Mta)
               is multiplied by one-third (the NRCs estimate of U.S. waters compared to world waters) and then multiplied
               by the ratio of the U.S. coastal population to the Gulf of Mexico's population, an estimate of 0.009 Mta of
               industrial effluent petroleum hydrocarbon contribution can be made.

               C. OIL SPILLS OCCURRING IN CONNECTION WITH OCS
                     OPERATIONS

                    Accidental discharge of oil can occur during almost any stage of exploration, development, or production
               on the OCS. Oil spills occur as a result of many causes (i.e., equipment malfunctions, ship collisions, pipeline
               breaks, human error, severe storms, etc.). Although many oil spills are not directly attributable to the
               oil-extraction process, they are indirectly related through the support activities necessary for recovery and
               transmission of the resource. Of the various potential OCS-related spill sources, the great majority of
               accidental discharges have resulted from production and transportation activities.
                    Impacts to sensitive resources from an accidental crude oil spill will depend on such factors as the initial
               size of the spill; the duration of the spill; whether the spill originated at the seafloor, surface, or at some point
               in between; the degree of weathering and dispersion that has occurred; and the degree of contact and
               sensitivity of a resource to the various components of the crude oil. Impacts range from direct effects, such
               as the smothering of organisms and toxic effects, to such indirect effects as disruption of a critical food
               source or interference with the ability to attach to a particular substrate. Impacts to a sensitive resource
               depend on the combination of factors present when the spilled crude contacts that resource. Refer to the
               analyses in Section IV.D. for a discussion of the variety of possible impacts to any specific resource.
                    The size of an oil spill can vary greatly from less than one barrel to hundreds of thousands of barrels being
               released over a period of time as a result of a single event. It is currently unknown if there is a direct
               relationship between the size of a spill and the event responsible for it. Because of this, discussions of
               estimates of the number, volume, location, and impacts resulting from accidental oil spills are based on spill
               size rather than source.











                 IV-100

                      The OCS Lands Act requires the Secretary of the Interior to investigate and prepare a public report on
                 each large oil spill. The MMS has issued regulations (30 CFR 250.41) requiring operators to report all
                 accidents orally to the District Supervisor and to confirm in writing spills greater than one barrel. The report
                 must include the cause, location, volume of spill, and action taken. In the case of spills greater than 50 bbl,
                 the sea state, meteorological conditions, and size and appearance of the slick must also be included in the
                 report
                      Offshore oil spills greater than or equal to 1,000 bbl are modeled by the OR Spill Risk Analysis computer
                 model that was constructed to model spills large enough to persist for several days.
                      The OSRA is a three-step process designed to assess the potential risk of contact of spilled oil with
                 sensitive environmental resources. This assessment is a long-term, statistical approach that is intended to
                 estimate both the likelihood of spill occurrence and the probability of contact with the resources over the
                 estimated 35-year life of the proposed action. The first OSRA step estimates the likelihood that one or more
                 oil spills will occur using a rate based on historic spills and past OCS production. In the second step, seasonal
                 contact probabilities are estimated using trajectories determined by mean surface currents and surface drift
                 induced by the winds. The third step combines the occurrence and contact probabilities to estimate the
                 combined likelihood of occurrence and contact for a given resource.

                 1. Historical Spill Occurmnce and Assumptions

                      It was not until 1978 that Congress charged DOI with the responsibility to report publicly on major OCS
                 accidents. However, some statistics on oil-spill events occurring in connection with OCS activities have been
                 maintained since 1964. Requirements for reporting spills to MMS have varied through time: as to size classes
                 reported and protocols for reporting. At present, 30 CFR 250.41 requires that industry report in writing to
                 MMS all spills over I bbl. Because of the historical variations on the reporting requirements for spills of less
                 than 1,000 bbl, the statistics should not be viewed as an accurate record of all possible spills; however, they
                 should be helpful in establishing limits on spill occurrence. For purposes of this analysis, spills are subdivided
                 into three categories--spills greater than I bbl and less than or equal to 50 bbl, spills greater than 50 bbl and
                 less than 1,000 bbl, and spills greater than or equal to 1,000 bbl. No complete database on spills less than or
                 equal to 1 bbl exists; therefore, it will not be considered in the discussions described in this section.

                 Spill Occurrence

                      Offshore Spills Less Man 1,000 bbl Occurring in Connection with OCS Operations

                      Spill sources include pipeline leaks or breaks on the OCS and platform mishaps. The sl     'A rates for spills
                 less than 1,000 bbl are relative to OCS production of crude and condensate data. No information is maintained
                 by MMS on small spills from shuttle-tankering operations because there has been no shuttle tanker activities
                 to date. The spill-rate calculations employed information on the number of spills and the adjusted annual OCS
                 production from 1971 to 1988. These spill rates differ from rates calculated for spills of 1,000 bbl or greater
                 (Section IV.C.I. below) because they are arithmetic averages rather than rates estimated using statistical and
                 trend analysis techniques. Implementation of improved safety practices in the OCS oil industry has apparently
                 contributed to a reduction of large spill events(Anderson and Labelle, 1990). Because it is then conceivable
                 that such safety practices may also influence the number of small spill events, these small-spill rates should be
                 viewed as conservative estimates. The small-spill rates for the two categories are as follows:

                                                                                      Spill Rate
                                                Spill Size                      (sl?ills/Bbbl produced)

                                           greater than 1 and                           152
                                             less than or equal to 50 bbl
                                           greater than 50 and                            6
                                             less than 1,000 bbl











                                                                                                                               IV-101

                      Experience shows that small spills occur in the vicinity of pipelines and platforms, and that these spills
                  probably will occur at random during the 35-year life of the proposed action. The duration or life span of an
                  oil spill depends, among other factors, on the initial volume of spilled oil. The former result imposes a
                  restriction on the likelihood that a small spill would contact coastal resources and shorelines, that is, only those
                  small spills close enough to resources or coastlines could make contact. The probable number of small spills
                  that could occur in the OCS planning areas was calculated by multiplying the adequate spill rate by the
                  estimated off production. The number of spills in the size class of greater than 1 and less than or equal to 50
                  bbl calculated to occur for the Base Case and High Case for Sales 142 and 143, and the appropriate planning
                  areas over the expected 35-year life of the proposed action are as follows (numbers are rounded means):

                                                                   Number of Spills
                                                  (greater than 1 and less than or equal to 50 bbl)

                                                                Base Case                   Hieh Case


                                   WPA                                8                           20
                                   CPA                               21                           47


                      The probable number of spills in the size class of greater than 50 and less than 1,000 bbl calculated for
                  Sales 142 and 143 for the Base and High Cases and appropriate planning areas over the expected 35-year life
                  of the proposed action are as follows (numbers are rounded means):

                                                                   Number of Spills
                                                      (greater than 50 and less than 1,000 bbl)

                                                                Base Case                   High Case

                                   WPA                                0                            1
                                   CPA                                1                            2


                      Using the above figures, qualitative assumptions regarding the probable numbers of small spills occurring
                  and contacting resources were made to provide a consistent basis for the analysis of the impacts of small spills
                  occurring in the Gulf of Mexico.
                      Since the duration or life span of an oil spill depends on the initial volume of spilled oil, only those areas
                  close to shorelines can significantly contribute to the number of spills that may contact land. Launch areas
                  close to the Federal-State boundary line are the closest sources of oil spills that may contact land.
                      For the Base Case in the CPA, it is assumed that three small spills of the size category of greater than I
                  and less than or equal to 50 bbl are likely to occur every 5 years, that a low percentage of these spills will occur
                  in proximity to coastal resources, and that a few of the total spills that will occur during the 35-year life of the
                  proposed action will contact the CPA coastline. In the WPA, it is assumed that a small spill of the size
                  category of greater than 1 and less than 50 bbl win occur every 5 years and that no spill in this size category
                  will contact the WPA coastline during the 35-year life of the proposed action. For the small-spill category of
                  greater than 50 and less than 1,000 bbl, it is assumed that one spill of this size will occur in the CPA during
                  the 35-year life of the proposed action but will not contact the coastline or resources. In the WPA, it is
                  assumed that no spills in this size category will occur and/or contact the resources or shoreline.
                      For the High Case in the CPA, it is assumed that seven spills in the size class of greater than 1 and less
                  than or equal to 50 bbl will occur every 5 years, that a low percentage of these spills will occur in proximity
                  to coastal resources, and that a few of these spills will contact the coastline of the CPA during the 35-year life
                  of the proposed action. For the WPA it is assumed that about three small spills every 5 years in this category
                  will occur, that a low percentage of these spills will occur in proximity to coastal resources, and that none










                 IV-102

                 of them will contact the coastline of the planning area during the lease life. For the small-spill size class of
                 greater than 50 and less than 1,000 bbl, it is assumed that one spill win occur in the WPA and that two spins
                 will occur in the CPA during the 35-year life of the proposed actions, none of these spills will contact the
                 coastline of either planning area.
                     It is assumed that a moderate number (between 5 and 25) of small spins in the size class of greater than
                 I and less than or equal to 50 bbI will occur each year from OCS program activities in the CPA and WPA
                 analysis area in proximity to coastal environments and that a few of these spills will contact both coastlines each
                 year.
                     For the CPA, it is assumed that about one spill in the size class of greater than 50 and less than 1,000 bbI
                 will occur each year from OCS program activities. None of these spills are assumed to contact the CPA
                 coastline during the 35-year life. For the WPA, it is assumed that no spill will occur and/or contact the
                 resources or coastline during the 35-year life from OCS program activities.
                     It is assumed that spills of one barrel or less will not significantly contribute to the short-term impact of
                 oil spills on sensitive environmental resources. This is because such small spills will weather rapidly, exhibiting
                 an extremely short life as a slick. However, once the oil components are dissipated into the atmosphere and
                 water column, they can contribute to the overall hydrocarbon loadings in the air and water. Impacts from
                 chronic long-term contamination by petroleum hydrocarbons on air and water quality are analyzed in this EIS.

                     Onshore Spills Occurring from OCS Coastal Operations

                     For the spill category greaer than I and less than or equal to 50 bbl, it is assumed that less than 10 spills
                 in each planning area spills will occur in the coastal zone from pipelines. These spills can occur from pipelines,
                 shuttle tankers, and barge operations near terminals in the coastal zone. For the spill category greater than
                 50 and less than 1,000 bbl, it is assumed that no spills from pipelines, shuttle tankers, barge operations or
                 onshore storage and processing facilities will occur in the inshore area.
                     Due to OCS Program activities, it is assumed that oil spills of greater than or equal to 1 and less than 50
                 bbI from OCS onshore transport, processing, or storage will occur about once a year (averaging between 25
                 and 42 spills). The operation of pipelines, tankers, and barges in the onshore areas will result in about one
                 OCS-related spin greater than or equal to 50 and less than 1,000 bbl every 10 years (averaging 4-6 spills).
                     Spills related to the OCS program can occur at onshore storage, processing, or transport facilities.
                 However, MMS does not regulate such activities, and the MMS spill database contains only spill incidents that
                 occur in Federal waters. The following observations can be made after examining oil-spill statistics contained
                 in the Emergency Response Notification System and published in several U.S. Coast Guard reports (USDOT,
                 CG, 1989). Locations of the spills kept in this database include open sheltered waters, river channels, ports
                 and harbors, territorial seas, contiguous zone, and high seas. For the years 1984-1986, river channels had the
                 most number of occurrences and the largest spills. This observation held true also for the Gulf region. 71@ypes
                 of off include both crude oil and petroleum products and can even include vegetable oils used in cooking. In
                 general, crude oil spills are the most common occurrence followed closely by diesel and fuel oil spills. Sources
                 of spills include marine vessels, land vehicles, nontransportation activities (refineries, bulk storage, onshore and
                 offshore production), and marine terminals. The data show that nontransportation facilities underwent more
                 spill incidents during 1984-1986, while marine vessels and terminals spill the largest volumes averaged over a
                 year.
                     Many of these categories are not broken down for the Gulf of Mexico area. The following information
                 about small spills in the Gulf is either derived from the above USCG reports or from personal communication
                 with the USCG. In the Gulf area, there were about 1,484 small spills occurring per year. About four spills
                 per year occur from transfer operations, or about 8 spills per 1,000 transfers; the vast majority of these spills
                 are less than 50 bbl (Oil Spill Intelligence Report, 1988; Westcott, personal comm., 1989).

                     Offshore Spills Greater Than or Equal to 1,000 bbl Occurring in Connection with OCS Operations

                     Data on spills of 1,000 bbl or greater from offshore platforms and pipelines have been kept accurately since
                 1964. Since 1964 there have been 10 oil spills of 1,000 bbl or more from platforms on the OCS, the last one












                                                                                                                                IV-103

                occurring in 1980. The majority of these are related to bad weather conditions. There have been 11 spills of
                1,000 bbl or more from pipelines on the OCS; the last two spills occurred on January 24, 1990 (14,423 bbl) and
                on May 6, 1990 (4,569 bbl). The majority of the 11 spills occurred due to anchor or trawl damage. These spill-
                event data, in conjunction with the historic production of OCS leases, allow the estimation of a spill rate with
                a significant degree of accuracy. This rate has not been uniform through time, and several revisions have been
                carried out (Nakassis, 1982; Lanfear and Amstutz, 1983; Anderson and LaBelle, 1990). The latest revision
                (Anderson and LaBelle, 1990) found a decrease in the spill rate of 40 percent for platforms and 50 percent
                for pipelines. These reductions were attributed to improved safety practices in the oil industry. The shuttle
                tanker spill rate is based on worldwide tanker spills from 1974 through 1985 (Anderson and LaBelle, 1990) (see
                the table below). The spill-rate values are as follows:

                                                    Spill Rates from Offshore OCS Operations
                                           (1,000 bbl or greater/billion bbl produced and transported)

                                           Platforms                                               0.60
                                           Pipelines                                               0.67
                                           Shuttle Tankering (at sea)                              0.90
                                           Shuttle Tankering (near port)                           0.40

                La?ge OCS Oil Spill Assumptions of Contact and Occurrence

                     Large oil spill occurrences do not follow a deterministic law-, they occur at random as stated earlier. In
                such cases, any attempt at spill prediction must use the methods of probability and statistics. Application of
                these methods results in a measure of the likelihood of spill occurrence. The analyst, using his/her insight, must
                interpret the meaning of the likelihood in applying the spill statistics to the analysis of spill impact on resources.

                     Large Offshore OCS Spill Assumptions

                     This section presents assumptions to be used for analytical purposes regarding the occurrences of large
                (1,000 bbI or greater) oil spills from OCS sources over the 35-year life of the proposed actions. Many of the
                assumptions regarding the occurrence of large spills from OCS activities are derived from the OSRA model
                results presented in Table IV-19. These assumptions are as follows:

                     (1) Base Case

                              Central Gulf of Mexico - One large offshore crude off spill is assumed to occur from OCS
                              activities (either from a platform or a pipeline) over the 35-year life of the proposed
                              action based on a probability of occurrence of one or more spills of 16 percent. The
                              median size of this spill is 6,500 bbl, and it is assumed to be subsurface.

                              Western Gulf of Mexico - No large offshore crude oil spills are assumed to occur from
                              OCS activities over the 35-year life of the proposed action based on a probability of
                              occurrence of one or more spills of 6 percent.

                     (2) High Case

                          -   Central Gulf of Mexico - One large offshore crude off spill is assumed to occur from OCS
                              activities (either from a platform or a pipeline) over the 35-year life of the proposed
                              action based on a probability of occurrence of one or more spills of 32 percent. This is
                              assumed to be a subsurface spill with a median size of 6,500 bbl.











                       IV-104

                       -   Western Gulf of Mexico - One large offshore crude oil spill is assumed to occur from.
                           OCS activities (either from a platform or pipeline) over the 35-year life of the proposed.
                           action based on a probability of occurrence of one or more spins of 16 percent.

                The large spin assumptions from all OCS Program activities are as follows:

                       -   Central Gulf of Mexico - It is assumed that there will be no large spills from shuttk@
                           tankers. Four large crude off spills of 6,000 bbl from offshore pipelines and three large:
                           oil spills of 7,000 bbl from platforms are assumed to occur.

                       -   Western Gulf of Mexico - It is assumed that there will be no large spills from shuttle-.
                           tankers. One large crude oil spill of 6,000 bbl from pipelines and one large oil spill of
                           7,000 bbI from platforms are assumed to occur.

                The tankering values presented in this table represent only that portion of the route covered away from
          the coastal and port areas. For the major Gulf ports accepting tankered crude oil, the values in Table IV-16
          represent the probable spill occurrence in the nearshore/port area itself.

                                                                              Table IV-16


                                                      Shuttle Tanker Spill Occurrence for Major Ports
                                           Receiving OCS-Produced Crude Oil (spills greater than 1,000 bbl)

                                                                                                                             OCS Program
                                                                        Base Cases                High Cases                   Activities
                                                                         (35 years)                (35 years)                  (35 years)
                                                                      Mean Prob.               Mean         Prob.            Mean Prob.
                       Port                                             No.        1+            No.         1+              No.        14-


                       Corpus ChristL Tex.                                          --                        --             0.01       1D)1V
                       Freeport, Tex.                                                                                          --
                       Galveston/Houston, Tex.                                                                                 --         --
                       Port Arthur, Tex./                                                                                    0.01       1910
                       Lake Charles, La.                                                                                       --         --
                       Miss. River Ports, La.                                                                                0.06       6 0).'o
                       Pascagoula, Miss.                                                                                     0.01       15-10
                       Mobile, Ala.                                      --                                                    --         --

                       Note: -- equals a value of less than 0.005 for both a mean number of spills and a probability.

                       Source: Price, 1991.

                Large Onshore OCS Spill Assumptions

                (1) Base Case

                       -   Central Gulf of Mexico - No onshore large pipeline, barge, or shuttle tanker spills are:
                           assumed to occur.


                       -   Western Gulf of Mexico - No onshore pipeline, barge, or shuttle tanker spills are assumed
                           to occur.











                                                                                                                              IV-105


                    (2) High Case

                         -  Central Gulf of Mexico - No onshore large pipeline, barge, or shuttle tanker spins are
                            assumed to occur.

                         -  Western Gulf of Mexico - No onshore pipeline, barge, or shuttle tanker spins are assumed
                            to occur.


                    The large spill assumptions from all OCS Program activities are as follows:

                         -  Central Gulf of Mexico - No large pipeline spills are assumed to occur onshore. At least
                            two spills from the barging of OCS crude are assumed to occur in Louisiana waters.

                         -  Western Gulf of Mexico - No large spills from onshore pipelines are assumed. At least
                            one spill from the barging of OCS crude is estimated to occur in Texas waters.

               Very Large Offshore Spills Greater Ran or Equ al to 100, 000 bbl Occurring in Connection with OCS Operations

                    For EIS purposes, a very large oil spill is defined as a spill of 100,000 bbl or greater. Only one very large
               spill, a 160,638-bbl pipeline spill, has occurred in the Gulf of Mexico from OCS operations. This spill occurred
               in 1967 and lasted 12 days, prior to the implementation of more expanded and stringent Federal regulations
               of OCS activities. From the above discussion it can be inferred that the probability of occurrence of an
               OCS-related oil spill in excess of 100,000 bbl in the Gulf of Mexico is very low. The historical record shows
               that there have been seven large spills exceeding 10,000 bbl--four from pipelines and three from platforms.
               The three platform spills resulted from blowouts, which, along with the Santa Barbara blowout incident,
               prompted the implementation of new and stringent operation regulations pertaining to drilling procedures,
               subsurface safety valves, and platform safety devices. Also, the training requirements and inspections by MMS
               personnel were increased as a result of the above incidents. The four pipeline spills occurred from anchor
               dragging across pipelines. A brief description of some of the earlier spills mentioned above can be found in
               Sections IV.C.I.c.(l) and (2) of the Final EIS for Sales 131, 135, and 137. An analysis of one possible very
               large oil spill is presented in Section IV.E.

               Projected Spill Sizes

                    Despite inherent variability, an expected "typical" size spill is useful in order to project the fate and effects
               of spills occurring in association with the OCS oil and gas industry operations. The following table provides
               a median spill size for spills greater than or equal to 1,000 bbl occurring from pipelines, platforms, tankers, and
               barges. The "median" of a set of measurements is defined as the middle value when the measurements are
               arranged in order of magnitude. The median size is used because it is considered a better indicator of a "likely"
               spill size since the average size is skewed by a few very large oil spill events.










                  IV-106


                                                                                   Median Size

                                           Source                                     J "bl

                                           Pipelines                                    6,000
                                           Platforms                                    7,000
                                           Shuttle Tankers                            21,0001
                                           Barges                                      1,5002

                          'Because no median size spill for shuttle tankers in the two size classes expected to be used
                            is known, a conservative approach has been taken, and the median size spins for all tankers
                            is used here.
                          2Source: Barges: The barge spill size is calculated from crude and barge spins that have
                            occurred in the Gulf of Mexico area since 1974. The average barge spill size is 6,000 bbl.
                            Source: Anderson, personal comm., 1990, for pipeline, platforms, and tankers spin sizes.
                  2. Characteristics, Fates, and Effects

                     The impact, behavior, and ultimate fate of an off spill depend not only on the ambient physical
                  environment but also on its chemical and physical properties. Oil is a complex mixture of thousands of organic
                  and a few inorganic compounds. These compounds include alkanes (aliphatics), naphthenes (cycloparaffinic),
                  aromatics, and asphaltics (asphaltenes and heterocyclic compounds containing oxygen, sulphur, and nitrogen).
                  A description of the characteristics of crude oil can be found in Section IV.C.2. of the Final EIS for Sales 131,
                  135, and 137.

                  South Louisiana Crude

                     South Louisiana crude is a typical crude oil from the Central Gulf of Mexico. The properties of an API
                  reference South Louisiana crude oil are provided in Table IV-12 of the Final EIS for Sales '131, 135, and 137,
                  as well as other crude oils from different geographical regions in the Gulf of Mexico. Variations in composition
                  can be expected for oils produced from different formations or fields within a region and from different
                  timeframes when sampled. A review of 92 crude oils produced from fields on the CPA OCS and coastal
                  Louisiana shows that a majority (51%) of the crude offs have API gravities between 330 and 3130 API. However,
                  the range of variability is great, with the lowest being 21.60 and the highest being 47.30 API.

                  Short-term Weathering Processes

                     A number of processes occur when oil is spilled in water, altering the chemical and physical characteristics
                  of the original oil mixture. Collectively, these are referred to as weathering or aging of the oil and will
                  determine, along with physical oceanography, the fate of the spilled oil. Weathering involves a number of
                  physical/chemical and biological processes that change the characteristics of the crude-oil mixture and reduce
                  the concentration of oil components in the slick. These processes include evaporation, dispersion, dissolution,
                  emulsification, biodegradation, photo-oxidation, sinking, and sedimentation. Any or all of these processes can
                  be expected to operate on spilled oil. Their relative importance depends largely on the oil's chemistry and the
                  oceanographic and meteorological conditions at the time of the spill. Eventually,a tar-like residue maybe left,
                  which would break up into tar lumps or tarballs. Types of weathering processes and transport pathways of
                  spilled oil at sea are depicted in Figure IV-6.
















                                                                                                           Atmospheric



                                                                                                             o







                                           B k Surface
                                            ut ischarge                                                               Wat       Oil
                                                                                                                               "S
                                             D                                                                         E m E-n-T, -I -I
                                                                                                                            'i.
                                            Thick Layer               Sea Surface Oil Stick                        Chocolate Mo-@_.e
                                               of Oil


                                                                                   Dissolution
                                                                           G(obular
                                                                           Dispersion    SoWbawng
                                                                                         Che,ic.t
                                                                            is         Tra @sfcrnatlons
                                                                         0A in vat.,                                          C
                                                                          emulsion




                                                                 Adsorpt on                                            a,bon
                                                                p.'o to
                                                                   ticutate                           r., 'on          C cte           c=  0@
                                                                  matter
                                                                             Dispersed
                                                                              Crude Oil
                                                                                                 Biodegradation



                                                                                               Assimilation into
                                                                                              Marine Food Chainj
                                                                                                  BioLogic.(
                                                     Butk-                                         etritus
                                                     r J:. ace
                                                 n@" U   9e

                                                                      Degradation or                                          /////X
                                                                        Assimilation                                      SeafLoor Sediment5
                                                                   by Benthic Organisms
                                           rT





















                    Figure IV-6. Processes Affecting the Fate of Spilled Oil (reprinted from Jordan and Payne, 1980).











                  IV-108



                      Slick Residence Time


                      Spilled Louisiana crude disperses and degrades rapidly under the influences of the Gulfs warm climatic
                  conditions and due to the properties of the oil. Because Louisiana crude evaporates rapidly, slicks observed
                  in Gulf waters have disappeared within days. Very few oil slicks have ever been tracked for more than 30 days.
                  (Spills from the Tormy Canyon tanker, Amoco Cadiz tanker, and the Lrtoc blowout accidents, which released
                  oil over a long time period, remained on the sea surface longer than 30 days, but the volumes spilled were
                  many times larger than the median spill described in this EIS.) For example, a slick from South Pass Block
                  60 of 42,000 bbl, spilled on August 2, 1973, was reported dissipated with only small patches remaining after
                  only 5 days. In examining the Chevron Main Pass blowout, only 50 percent of the oil lost oDuld be accounted
                  for--25-30 percent of the oil was estimated lost due to evaporation, 10-20 percent of the oil was removed from
                  the sea surface by skimming and other recovery techniques, less than I percent was believed dissolved in
                  seawater, and less than I percent sunk and was deposited in the sediment within an 8-km radius of the wen.
                  Evidently, the remaining off became emulsified and dispersed to undetectable levels (less than 1 ppm) or
                  became biodegraded and/or photo-oxidized (McAuliffe et al., 1975). Dispersants were used in the cleanup
                  operations and also in the water sprayed on the burning platform to help disperse the oil. Based on the above,
                  10 days, is chosen as the most likely sea-surface residence time. Research regarding dominant weathering
                  processes indicate that after 10 days the oil properties have changed extensively and the original volume has
                  decreased greatly (Table IV-17). The floating oil is largely devoid of its volatile (acutely toxic) components,
                  and the slick is breaking up.

                      Weathering Processes

                      Table IV-17 summarizes the time periods expected and the percent loss of the original volume of an oil
                  spill due to weathering processes. Section IV.C.2. of the Final EIS for Sales 131, 135, and 137 describes the
                  major weathering processes in detail. The following is a summary of this section.

                      Weathering Processes Less 7han 10 Days

                      After a spill occurs, a "slick" forms because of the low solubility of most petroleum components. Major
                  processes affecting the slick's volume include spreading, evaporation, dissolution, and dispersion. By far,
                  spreading of the oil to a thin film is the most important process because spreading enhances the ability of other
                  weathering processes to act on the slick. The more volatile hydrocarbons are lost to the atmosphere during
                  the first 24 hours from evaporation of the slick. Based on an analysis by Torgrimson (198-1), 48 percent of a
                  typical medium-light crude oil would be lost due to evaporation. Low-molecular-weight compounds win also
                  rapidly dissolve in the water column. Dissolution can occur directly from the floating slick or from dispersed
                  oil in the water column. The process is in competition with evaporation, which is orders of' magnitude faster,
                  so many soluble compounds are preferentially removed by evaporation. The agitation of oil slicks due to the
                  breaking of waves, the action of the surf, and the surface turbulence supply the energy to drive off into the
                  water column, forming small droplets of stable emulsions from 5 micrometers to several millimeters in size that
                  are dispersed into the water column (oil-in-water emulsions). Larger oil droplets probably rise and coalesce
                  with the slick, while the smaller oil droplets are conveyed and permanently incorporated into the water column
                  (NRC, 1985). This process, along with evaporation, largely determines the lifetime of a slick.
                      For purposes of analysis, the following assumptions about weathering of the projected spills are made: the
                  surface slick will lose about 60 percent of its original volume by 10 days, primarily due to evaporation; and
                  under rough wave conditions, oil will be dispersed 20 m in the water column. If one assumes that 10 percent
                  of the slick is cleaned up, then, by 10 days, 70 percent of the slick is expected to be removed from the surface.











                                                                                                                          IV-109













                                                                  Table IV-17

                                          Mass Balance of a Typical Gulf of Mexico Crude Off Spill'

                                                                              % Loss of                 % Loss of
                                                                              Original Slick            Original Slick
                                                    Time Scale                Volume                    Volume
                 Process                            (in days                  (10 d                     (30 dW)
                 Evaporation                        1-10                      33%-67%                   33%-67%

                 Dissolution                        1-10                      1%-5%                     1%-5%

                 Dispersion                         1-30                      10%-15%                   included in sinking
                                                                                                        and sedimentation rate


                 Photo/Auto-oxidation               3-365                     <1%                       5%

                 Biodegradation                     5-720                     1%                        included in sinking
                                                                                                        and sedimentation rate
                 Sinking and Sedimentation          10-365                    <1%                       20%-34%

                 Tar Residue                        10-365                    <1%                       1%-30%

                 Offshore Skimming and                                        10%                       15%
                 Recovery Cleanup Operatins

                 Total Volume Loss from Water Surface                         56%-98%                   100%

                 'It is assumed that the spill does not contact land.
                 2Ranges given provide an overview of crude oil fate in general. The most likely percent for Louisiana crude
                 oil due to that process is provided in the narrative entitled "Weathering Processes Less Than 10 Days."

                 Source: USDOI, MMS, Gulf of Mexico OCS Region estimates, 1989.











                  IV-110



                  Weathering Processes Greater 77zan 10 Days

                      Major processes include emulsion formation, sedimentation, chemical- and photo-oxidation, and microbial
                  degradation.
                      Because most of the components of petroleum are relatively insoluble in water, an important process in
                  weathering of the slick is the formation of emulsions. Facilitated by increased viscosity and density due to
                  evaporation and dissolution, the heavier fractions of oil take on a highly viscous consistency caused by the
                  formation of a water-in-off emulsion termed "mousse" because of its color and consistenc@. Emulsification
                  impedes cleanup operations and slows down the weathering process by limiting the exposed surface area.
                  Many Gulf crudes have been found not to form mousse emulsions.
                      Sedimentation of the dispersed or surface emulsified oil occurs once an increase in density is sufficient to
                  sink the material. In Gulf coastal areas characterized by fine-sediment salt marshes or 'Influenced by the
                  Mississippi River's large sediment plume, the amounts of suspended particles in the water are high, and on in
                  this turbid area is soon carried to the bottom.
                      Spilled off undergoes chemical changes such as photo- and auto-oxidation, producing a number of products
                  including C02, carboxylic acids and diacids, esters and lactones, aldehydes, alcohols, hydroperoxides, phenols,
                  sulfoxides, and combinations of these products. Besides influencing the solubility of the components of off
                  spills, oxidation enhances dispersion and emulsification. The effects of oxidation are coniplex and may be
                  partially beneficial and partially deleterious.
                      Biological processes include biodegradation and ingestion by zooplankton and larger forms of marine
                  organisms. The rate of decomposition is dependent on the nature and abundance of the indigenous microbial
                  assemblage, the available inorganic nutrients and oxygen, and the ambient temperature.                     Bacterial
                  decomposition of oil is the most important long-term, process removing spilled petroleum compounds from the
                  environment. Biodegradation of hydrocarbons occurs on the sea surface, in the water column, in the bottom
                  sediments, and on the coast once the oil is beached. Microbial degradation of oil beached from the Exxon
                  Valdez oil spill was accelerated after scientists added fertilizer to enhance microbial growth (USEPA, 1989).
                  Bioremediation of the spilled oil proved one of the most effective cleanup techniques used.
                      South Louisiana crude oil showed the highest rate of degradation in numerous studies conducted on
                  biodegradation rates of different oils (Zobell and Prokop, 1966). Jeffrey (1977) states that in 1977 Walker and
                  Colwell found as high as a 97 percent loss of oil in only 30 days from Louisiana sediments due to bacterial
                  degradation in one instance.

                  Subsur
                        .face Plume Formation

                      Not all spills occur at the surface. The Ixtoc: subsurface spill resulted in higher concentrations of oil in the
                  water column than usually measured beneath surface slicks. The subsurface plume contained higher
                  concentrations of volatiles, thus showing that the plume was not surface oil driven back into the water column.
                  It was theorized that another mechanism--subsurface plume formation--was responsible for the phenomena.

                  Long-term FatelTar Residue Formation

                      Natural weathering (evaporation, dissolution, photo-oxidation, and microbial oxidation) and degradation
                  processes will remove nearly all of the original volume of the spilled surface slick within 30 days (Wheeler,
                  1978). Any tarry residue left behind will break up into smaller fragments from continuing wave action and
                  form tarballs in the water column. Further degradation is retarded since the surface-to-volume ratio of
                  unspread tar is small and tarballs are resistant to microbial degradation; therefore, their lifetime could be on
                  the order of several months to years (Geyer, 1980). Some tarballs reach the coast. An average of 14,000 bbl
                  of floating tar exist in the Gulf of Mexico (Geyer, 1981).
                      Butler et al. (1973) found that around 30 percent of most oil discharged to the ocean remains in the form
                  of tarballs or lumps. In contrast, Louisiana crude and some other northern Gulf coast crude oils do not seem
                  to form tarballs (Jeffrey et al., 1974) because of low asphaltene and nitrogen-sulphur-oxygen (NSO)
                  components. Tarball formation is limited to spherical accretion caused by persistent convergence and supply











                                                                                                                              IV-111

                to the oil residues (Heaton et al., 1980). Spills from the oil types in the Eastern Gulf may form a significantly
                higher. percentage of tar material because of the different chemical compositions of the oil.
                     The distribution and long-term fate of an oil slick, if it contacts land before breaking up, is a function of
                weathering processes and coastal geomorphology, the kinetic energy of the area, the thickness of the beached
                off, and the porosity of the shoreline sediments. Oil coming ashore into tidal flats, mangrove swamps, or salt
                marshes could be spread farther inland by each tidal movement and wave action (Jackson et al., 1989). Once
                entering inland waters, the oil could either spread out into a thin film or reach areas sheltered from waves and
                tidal currents and form a thick layer of oil that can remain for years. It is assumed that once oil contacts land,
                it is already spread into a 1 mm. thickness.
                     Most oil that will reach the Gulf of Mexico shoreline would contact fringing beaches and barrier islands.
                The distribution and physical dispersion of an oil slick once it contacts a coastal beach is dependent upon the
                level of kinetic energy of the coastal environment. Often, oiled beaches are cleansed by the natural action of
                abrasion and sediment scouring by wave activity. Much of the oil beached on the Texas shoreline from the
                Ixtoc blowout was removed during a hurricane. Stranded oil can be washed back out to sea and can be rolled
                along the bottom in the shallow-water zone by waves and currents, eventually either emerging somewhere else
                along the shoreline; washing back onshore in the form of hard, tarry masses (tarbaffs); or resting offshore in
                the intertidal zone. Some beached oil becomes buried by the rapid changes in beach morphology that occur
                from natural cycles of erosion or from deposition of migrating beach sands. The depth of oil burial and the
                thickness of oiled sediments increases as the grain size increases. Although the entire sand column may
                become lightly contaminated, most of the oil exists in a highly concentrated band of oil-impregnated sand that
                can persist for years. These buried oil layers have been shown to migrate downwards within the beach
                sediment, eventually stabilizing deep within the beach at or near the water table or reaching an impermeable
                layer and migrating along the layer until emerging in the lower intertidal or subtidal sediments at the foot of
                the beach (Long et al., 1981). Rates of migration of buried oil studied after the Amoco Cadiz spill ranged from
                0.25 to 1.0 millimeters per tidal cycle. According to Long et al., these rates agree with rates determined
                experimentally for a variety of sediment types.
                     In the 1970 South Timbalier Block 26 oil spill of 53,000 bbl, the self-cleaning phenomena of south
                Louisiana beaches was the most effective means of removing oil from the beaches. The beaches cleaned
                themselves in a few days after oil was deposited due to (1) the sand being hard packed and, therefore, resistant
                to penetration by off and emulsified oil and (2) the beaches were narrow and shallow; therefore, they were
                easily swept clean by the changing tides (Berry, 1972).
                     The ultimate fate of environmentally dispersed petroleum in open water is poorly understood. A study
                by Energy Resources Co. for BLM (1982) found no Ixtoc oil in offshore South Texas OCS (STOCS) sediments.
                Only 2 percent of the off spilled from the Ixtoc blowout was ever accounted for (either found on beaches or
                residing offshore in tar mats). Perhaps 5-10 times as much oil passed through the Texas OCS region, largely
                in the form of small patches of emulsified oil. The researchers believed the oil could be tied up with the
                mobile, suspended sedimentary material (nepheloid layer) that exists near the bottom sediment/water interface
                or ultimately found its way onto the slope and abyssal plain.
                     Based on information about Gulf Coast oil spillage, concentrations of spilled petroleum that reach coastal
                sediments are assumed to be degraded to background levels within 1-2 years (Brown, 1980, McAuliffe et al.,
                1975; Butler et al., 1976).

                Toxic Effects of Oil Spills

                     Most of the historical oil spills that occurred in connection with OCS oil industry operations in the Gulf
                have probably resulted in no serious, short-term, deleterious effects. This conclusion is based on a review of
                the sparse documentation of the effects of Gulf of Mexico oil spills and on the rapidity with which Louisiana
                crude disperses and degrades.
                     Each spill is a unique event, with a number of factors interacting to determine its effects; however, all spills
                occurring in the Gulf could be potentially harmful. The variability documented in the literature regarding
                environmental effects of oil spills is due to differences in oil components, environmental conditions, and the
                organisms encountered. The most damage from an oil spill occurs if a spill from the open ocean reaches
                confined, shallow water bodies where waterfowl or aquatic organisms are concentrated.










                 IV-112

                     The ultimate impact and recovery of an ecosystem from petroleum contamination depend on the physical
                 and chemical form of the off and the state of the ecosystem at the specific time of impact. The movement of
                 oil into the water, its chemical changes, its effects on aquatic organisms, and its persistence in the sea are all
                 influenced by (1) the type and characteristics of the off (for example, its viscosity and percent aromatics); (2)
                 the amount and duration of oil spilled; (3) sea state, in particular the tidal cycle and wave activity; (4) the
                 location of the spill, including the physiography of the area and the distance from shore; (5) the geographical
                 and topological configuration of the affected coast, including textural characteristics of shore sediments; (6) the
                 climatic conditions, in particular temperature, wind, and solar radiation; (7) the biota of the area; (8) the season
                 of the spill; (9) the previous exposure of the area to oil; (10) the area's exposure to other pollutants; and (11)
                 the effectiveness of oil response measures taken.
                     Short-term effects of oil spills that result in biological loss occur by direct kill through coating and
                 asphyxiation; by contact poisoning or by incorporation of water-soluble toxic, carcinogenic, or mutagenic
                 components of off; by destruction of the generally more sensitive juvenile forms of organisms or of the food
                 source of higher trophic species; and by modification of habitats, delaying or preventing recolonization (Blumer,
                 1971).
                     The toxicity of petroleum to marine organisms is dependent on the concentration and o:)mposition of its
                 individual hydrocarbons and the exposure length of the various components. The toxicity of the oil will be
                 altered as it weathers, as a result of the changes in its chemical composition.
                     Table IV-18 contains LCso values for marine organisms indigenous to the Gulf of Mexico, including
                 commercially important species as well as basic components of the food web. Although planis are not usually
                 listed, an LC50 value for mangrove propagules (not on the table) is given as 0.5     J/M2 for light Arabian crude
                 oil (Hoi-Chaw and Meow-Chan, 1985). The refined offs, No. 2 fuel oil and Bunker C oil, were: more toxic than
                 the crude oils. The WSFs were more toxic than the oil-in-water dispersions.
                 I Results of the Oil Spill Risk Analysis

                     As stated in Section IV.C.1., the historical database for large spills (greater than or equal to 1,000 bbl) is
                 more complete, and the resulting spill rate has greater reliability. Also, more time has been devoted to their
                 study from all aspects because of their dramatic impacts and longer times over the sea surface, among many
                 other factors. As a result, our understanding and experience regarding large spills are considerably more
                 sophisticated than for small spills. Regardless of this emphasis and accumulated knowledge, statistical
                 techniques are used to predict the occurrence of oil spills. For this procedure, it is assumed that spill
                 occurrence can be described as a Poisson process. The parameters of importance become the spill rates
                 (Section IV.C.I.) for the different activities of interest, and the estimated production is distributed or
                 aggregated among the different activities. Using this information, the appropriate computations were
                 performed; and the results for the Base and High Cases and OCS program activities' areas are presented in
                 Table IV-19. This table presents the estimated production, the mean number of spills, and the probability that
                 one or more oil spills of greater than or equal to 1,000 bbl will occur over the 35-year life of the proposed
                 action.


                 Trajectory Simulation

                     Oil spill trajectory simulations are conducted using mean seasonal surface currents and surface drift
                 produced by winds sampled every 3 hours for 30 days until land is contacted or the trajectory moves out of the
                 study area. Hypothetical spill trajectories were simulated for each of the potential launch sitesacross the entire
                 Gulf (Figure IV-7). These simulations presume 500 spills occurring in each of the four seasons of the year
                 from each launch site. The results are presented as probabilities (expressed as percent chance) that an oil spill
                 starting at a particular launch site will contact a certain environmental resource or a land segment within 3, 10,
                 or 30 days. A summary of the trajectory analysis (for 10 days) for all launch sites across the Gulf that present
                 a potential risk to the land segments is given in Table IV-20. This table illustrates that if, for example, an oil
                 spill were to occur in the Western Gulf, the probability (expressed as percent chance) of contact with a certain
                 land segment within 10 days ranges from less than 0.5 percent to 41 percent. The corresponding counties for
                 the highest percent chance of contact are Calhoun County in Texas, and Plaquemines Parish in Louisiana.













                                                                                                                          Table IV-18


                                                                                                    LC50 Values for Some Gulf of Mexico Marine Animals

                                                                                Southern Louisiana Crude            Kuwait Crude                  No. 2 Fuel Oil                    Bunker C Oil        Weathered IXTOC I
                                                                                     OWD7 WSF8                      OWD          WSF              OVID        WSF                OWD           WSF             OAS9
                         Species                                LC50 (hours)               (ppm)                          (ppm)                         (PPM)                           (Ppm)                  (PPM)

                         Mysid
                         (Mysidopsisal-y-)l                         48                37.5          8.7             63.0           6.6               1.3         0.9                -          0.9

                         Grass shrimp
                         (Palaemonelespugio)l                       96                200        >16.8            6,000        >10.2                 3.0         3.5                -          2.6

                         Brown shrimp postlarvae
                         (Penaeus azlecus) 1                        96             >1,000        >19.8                 -           -                 9.4         4.9                -          1.9

                         Sheepshead minnow
                         (Cyprinodon variegalus) 1                  96             29,000        >19.8         >80,000             -              93             6.3                -          3.1

                         Silverside
                         (Menidia beryllina) 1                      96              3,700           5.5           9,400            6.6               -           3.9                -          1.9

                         Longnose killifish
                         (Fundulus similus) 1                       96              6,000          16.8          14,800        >10.4              33             3.9                -          1.69               -

                         Copepods of coastal Texas and
                         laboratory-reared amphipods2               96                   -          -                  -           -                 -           -                  -          -              >13.5

                         Red drum eggs and larvae
                         (Scidenops ocellala)3                      24                   -          -                              -                             -                  -          -               >51

                         Polychaeta
                         (Capitella capilata)4                      96                   -         12.0                            9.8               -           2.3                -          0.9                -

                         Isopod
                         (Ligia exolica)5                           96                   -          -                  -           -              36.5        *10                   -          -

                         Brown Shrimp
                         (Penaeus azlecus)6                         96
                         Postlarvae                                                      -          -                  -           -                 -           6.6                -          -
                         Early juveniles                                                 -          -                  -           -                             3.7                -          -
                         Late juveniles                                                  -          -                  -           -                             2.9                -          -






                                                                                                                                                                                                                                          ILI









                          Table IV-18- LC50 Values for Some Gulf of Mexico Marine Animals (continued)
                                                                                 Southern Louisiana Crude           Kuwait Crude                  No. 2 Fuel Oil                  Bunker C Oil        Weathered IXTOC I
                                                                                      OWD7 WSF8                     OWD         WSF               OWD         WSF               OWD         WSF               OAS9
                          Species                               LC50 (hours)                (ppm)                        (PP-)                         (ppm)                          (ppm)                   (ppm)
                          White Shrimp
                          (Penaeus selijerus)6                       96
                          Postlarvae                                                                                                                -          1.4                -
                          Juveniles                                                      -          -                 -           -                 -          1.0                -

                          Grass Shrimp
                          (Palaemonelespugiofi                      96
                          Larvae                                                         -          -                 -           -                 -          1.2                -           -                  -
                          Postlarvae                                                     -          -                 -           -                 -          2.4                -           -                  -
                          Adults                                                         -          -                 -           -                 -          3.5                -           -                  -

                          Opossum Shri  mp
                          (Mysidopsis al_y_)6                       96
                          Postlarvae                                                     -          -                 -           -                 -          1.75               -           -                  -
                          Adults                                                         -          -                 -           -                 -          0.65               -           -                  -

                          1 Anderson et al., 1974.
                          2Lee et al., 1980.
                          3Rabalais et al., 1981.
                          4Rossi et al., 1976.
                          5Dillon et al., 1978.
                          6Neff et al., 1976.
                          70il-in-water dispersions.
                          8Water-soluble fraction.
                          90il accommodated in seawater.
                          101'ailed to produce 50916 mortality.






















                                                                                                                                          Table IV-19

                                                                          Oil-spill Occurrence Probability Estimates for Spills Greater than or Equal to 1,000 Barrels Resulting Over the Life of the
                                                                                                  Proposed Actions, from OCS Program Activities* for Proposed Sales 142 and 143

                                                                                                                                   Mean                                         Probability             Probability             Probability
                                                                                 Mean                     Mean                     Number                                       (% chance)              (% chance)              (% chance)               Probability
                                                                               Numher                   Number                     of Spills              Mean                  of One or               of One or               of One or               (% chance)
                                                                               of Spills                of Spills                  from                 Number                  More Spills             More Spills             More Spills              of One or
                                                          Volume                 from                     from                     Shuttle              of Spills                   from                      from                    from              More Spills
                            Source                        (BBO)               Platforms                Pipelines               Tankers"                   (total)               Platforms                Pipelines              Tankers"                     (total)


                            Proposed Actions

                                 Base Case

                                 WPA                      (0.05)            0.03                     0.03                      0.01                   0.07                          3                         3                       1                      7
                                 CPA                      (0-14)            0.08                     0.09                      0.00                   0.18                          8                         9                       n                      16

                                 High Case

                                 WPA                      (0.13)            0.08                     0.07                      0.02                   0.17                          8                         7                       2                      16
                                 CPA                      (0.31)            0.19                     0.21                      0.00                   0.39                          17                        19                      n                      32

                                 OCS Program
                                  Activities* *

                                 WPA                      (1-20)            0.72                     0.72                      0.11                   1.56                          51                        51                      11                     79
                                 CPA                      (5.46)            3.28                     3.66                      0.01                   6.94                          96                        97                      1                      99+
                                 EPA                      (0.19)            0.11                     0.01                      0.16                   0.28                          11                        1                       15                     24
                            OOCS Program Activities are defined as all oil and gas activities occurring GulWde during the life of the proposals as a result of past, proposed, and future sales in the OCS.
                            "For the proposed actions and OCS Program activities, some transport of OCS produced oil by shuttle tankers is expected.
                            Note: n - represents equal to or less than 0.5% probability.

                            Source: Price, written comm., 1990.









                                                                                                                                                                                                                                                                        tA







                                                   11    12      13      14    LOUISIANA            21  22   23 24 25      27   282   30
                                           10                                               20                                                31
                                                                                      18                                                            32
                                      9                                       15                      68        0     71                               33
                                                             so        31       16    17  19    53  54 69             73    76          77    78
                                                     14            1'--       36      7                               75        79    so      al           34
                             7                 13     16     32        33     35          51         57       133     134       82    83      84  a
                                                                   -                  39       56                 1                                        35
                          6        4    12            17     34        35     40     41 42  58       59       135     136       86    a7      15a a         3
                       5        3          7   1   Is      19       20        43      44     60      61       137     130       so    91      92  9                 17
                                                                                                                                                             38
                                           a       21      22       23        45      46     62      63       139     140       94    95          97           9
                                                                                                                                                              40
                      3                    10      24      25       26        47      48     64      65       141     142       98    99      100 1011 02     41
                                           11      27       28      29                                                144       103   104     m 106  107 10
                    ---2                                                      49      50     66      67       143  ---                                         42
                                                                                                                      145       109   110     111 112  113 114 115
                                                                                                                          -                                         43
                                                                                                                                116   117     Ila 119  120 121 122

                                                                                                                                                         128  29
                                                                                                                                              125


                                                                                                                                              131
                     Numbers adjacent to the coast indicate land segments (coastal counties/parishes).
                     Numbers offshore indicate oil spill launch sites.







                Figure IV-7. Land Segments and Launch Sites Used in the Minerals Management Service Oil Spill Risk Analysis Model.






















                                                                                                                    Table IV-20


                                                              Probabilities (expressed as percent chance) that an Oil Spill (greater than or equal to 1,000 bbl) Starting at a Particular Location
                                                                                      Will Contact a Certain Land Segment Within 10 Days (Sales 142 and 143)

                           Land Segment'                                                                    Hypothetical Spill Location2
                                                 wol          W02           W03           W04           W05       W06           W07            W12            W13         W14         W15           W16


                                1                13           1             n             n             n           n             n               n           n           n             n            n
                                2                5            2             n             n             n           n             n               It          n           n             n            n
                                3                8            17            2             n             n           n             n               n           n           n             n            n
                                4                1            12            8             n             n           n             n               n           n           It            n            n
                                5                n            5             17            1             n           n             n               n           n           n             n            n
                                6                n            2             22            4             n           n             n               n           n           n             n            n
                                7                n            n             12            41            8           2             n               1           n           n             n            It
                                8                n            n             n             23            7           n             1            38             1           n             n            n
                                9                n            n             n             n             n           n             n               9           12          n                          n
                                10               n            n             n             n             n           n             n               n           26          it
                                11               n            n             n             n             n           n             n               n           n           16            n
                                12               n            n             n             n             n           n             n               n           n           4             n            n




                          Land Segment                                                                      Hypothetical Spill Location

                                                                     C30         C31      C32        C33        C36         C37     C38           C39      C41


                                11                                   2           n          n           n       a           n          n          n           n
                                12                                   42          2          2           n       n           n          n          n           n
                                13                                   2           25         n           I       n           n          n          n           n
                                14                                   n           6          n           n       5           n          n          n           n
                                15                                   n           1          n           n       11          n          n          n           n
                                16                                   n           n          n           n       27          16         3          3           n
                                17                                   n           n          n           n       n           21         n          5           1
                                18                                   n           n          n           n       n           6          n          1           n
                                19                                   n           n          n           n       n           I          n          n           n























                            Table IV-20. Probabilities (expressed as percent chance) that an Oil Spill (greater than or equal to 1,000 bbl) Starting at a Particular Location Will Contact a Certain Land Segment Within 10 Days
                                           (Sales 142 and 143) (continued)

                            Land Segment                                                                        Hypothetical Spill Location
                                                  C51      C52      C53       C54      C55      C56      C57      C58      C59      C60       C61      C62      C63      C64       C65      C66     C67       C68       C69


                                  17               3        n         n         n       n        n          n      n          n       n        n        n         n        n        n        n        n         n         n
                                  18               6        n         n         n       n        n          n      n          n       n        n        n         n        n        n        n        n         n         n
                                  19               34       65        32        5       n        29         1      12         1       2        n        n         n        n        n        n        n         n         1
                                  20               n        n         10        1       n        n          n      n          n       n        n        n         n        n        n        n        n         4         2
                                  21               n        n         n         n       n        n          n      n          n       n        n        n         n        n        n        n        n         23        4
                                  22               n        n         n         n       n        n          n      n          n       n        n        n         n        n        n        n        n         17        5
                                  23               n        n         n         n       n        n          n      n          n       n        n        n         n        n        n        n        n         9         3







                    In   less than 0.5 percent.
                    2Some hypothetical spill locations showing less than 0.5 percent chance of contact are not shown.

                    Note: Rows with all values less than 0.5 percent are not shown.











                                                                                                                     IV-119



               Estimated Number of Oil Spills Occurring and Contacting Sensitive Resources

                  The final phase of the OSRA combines the projected mean number of spill occurrences with the
               probabilities of contact provided by the trajectory analyses. The results are given in a series of tables
               presenting two values for each land segment (Tables IV-21 and IV-22) and environmental resource across the
               Gulf within 10 days. The two values represent (a) the probability of one or more spills occurring and
               contacting the environmental resource and (b) the estimated mean number of spills that might occur and
               contact the environmental resource. These tables also show only those land segments and environmental
               resources considered most at risk of contact by an oil spill resulting from OCS program activities or from
               import operations and reaching these resources within 10 days. In many areas around the Gulf, several
               sensitive resources occur within the same geographic limits. For the sake of efficiency in running the model,
               most of these areas were submitted only once, with the results being renamed or combined to represent other
               resources in the same area. Following is a list of the environmental resources submitted for the OSRA.
               These environmental resources were also used by the Leasing and Environment staff in the Gulf of Mexico
               OCS Region to define a second set of resources in the same area.

                               The results from:                                Also represent:

                           Timbalier Bay                                     Timbalier Bay Seagrass Beds
                                                                             Isle Dernier/Timbalier Island Coastal Barrier

                           Chandeleur/Breton Coastal Barrier                 Chandeleur Sound Seagrass Beds
                                                                             Chandeleur/Breton Sound

                           Upper Keys, Lower Keys, and                       Keys Brown Pelican Nesting/Foraging
                           Florida Bay Seagrass Beds

                           Mississippi Sound                                 Gulf Islands National Seashore Rec. Beaches

                           West Plaquemines Coastal Barrier and Land         West Deltaic Plains Marshes
                           Segments 14, 15, 16, 17, and 18

                           Upper Florida Keys                                Upper Keys Mangroves
                               Upper Keys Seagrass Beds
                               Upper Keys Coral Reefs

                           Lower Florida Keys                                Lower Keys Mangroves
                               Lower Keys Seagrass Beds
                               Lower Keys Coral Reefs

                           Land Segment 43                                   Monroe County Tourism
                           Upper Florida Keys
                           Lower Florida Keys

                           Land Segment 21                                   Hancock County, Miss., Pelican Habitat

                           Land Segment 22                                   Mobile County, Ala., Pelican Habitat











                                                                                              Table IV-21
                                                  Probabilities (expressed as percent chance) of One or More Spills Greater than or Equal to
                                          1,000 bbl, and the Estirriated Number of S;ifls (mean@ Occurrin
                                                                                                              . g and Contacting Land Segments Over the
                                                                              Life of the roposed ction Wit in 10 Days
                                                                                       (Central Gulf Sale 142)
                      Land Segment/                                           Base Case                  High Case                     Gulfwide                       OCS Program
                                                                              PrOCPA,
                                                                                b                        (CPA)                       'm  rt Tankering                 Activities
                   Environmental Resource                                            Mean                Prob   Mean                 Propbo Mean                      Prob Mean
                   1 - Cameron TX                                                                                                    n     0.0                        n     0.0
                   2 - Willa     TX
                   3 - KeneZ, TX                                                                                                     n     0.0                        n     0.0
                   4 - Kleberg, TX                                                                                                   1     0.0                        n     0.0
                   5 - Nueces, TX et al.                                                                                             4     0.0                        2     0.0
                   6 - Aransas, TX                                                                                                   9     0.1                        2     0.0
                   7 - Calhoun, TX                                                                                                   6     0.1                        3     0.0
                   8 - Matagorda TX                                                                                                  n     0.0                        1     0.0
                   9 - Brazoria,N                                                                                                    3     0.0                        1     0.0
                   10 - Galveston, TX et al.                                                                                      22       0.3                        8     0.1
                   11 - Jefferson, TX                                                                                                3     0.0                        1     0.0
                   12 - Cameron, LA                                                                                               23       0.3                        6     0.1
                   13 - Vermilion, LA                                                                                                n     0.0                        6     0.1
                   14 - New Iberia, LA                                                                                               n     0.0                        6     0.1
                   15 - St. Mary, LA                                          n      0.0                 n      0.0                  n     0.0                        9     0.1
                   16 - Terrebonne, LA                                        1      0.0                 2      0.0                  n     0.0                      32      0.4
                   17 - Lafourche LA                                          n      0.0                 n      0.0                  1     0.0                      10      0.1
                   18 - Jefferson, UX                                         -      -                   -      -                    1     0.0                      11      0.1
                   19 - Plaquernines LA                                       1      0.0                 1      0.0               21       0.2                      54      0.8
                   20 - St. Bernard, CX et al.                                -      -                   -      -                    1     0.0                        1     0.0
                   21 - Hancock, MS et al.                                    -      -                   -      -                    3     0.0                        3     0.0
                   22 - Mobile, AL                                            -      -                   -      -                    2     0.0                        1     0.0
                   23 - Baldwin AL                                            -      -                   -      -                    n     0.0                        n     0.0
                   24 - Escambla, FL                                          -      -                   -      -                    n     0 'Q                       n     0.0
                   44 - Dade, FL                                              -      -                   -      -                 18       0.2'                       n     0.0
                   45 - Broward, FL                                           -      -                   -      -                    2     0.0                        n     0.0
                   Land                                                       2      0.0                 4      0.0               73       1.3                      85      1.9
                   Western Deepwater Boundary                                 n      0.0                 1      0.0               71       1.2                      30      0.4
                   Aransas Refuge                                             n      0.0                 n      0.0                  4     0.0                        2     0.0
                   Tamaulipas, Mexico                                         n      0.0                 n      0.0                  n     0.0                        n     0.0
                   Central Deepwater Boundary                                 5      0.1                11      0.1               96       3.3                      59      0.9
                   Timbalier Bav                                              1      0.0                 ?.     n.n                  1     n.n                      in      n.A
                   Barataria Bay'                                             n      0.0                 n      0.0                  9     0.1                      36      0.4
                   Mississippi Sound                                          n      0.0                 n      0.0                  7     0.1                        6     0.1
                   Caminada Headland                                          n      0.0                 7      0.0                  4     0.0                      21      0.2
                   West Plaquemines Coastal Barrier                           n      0.0                 1      0.0               28       0.3                      52      0.7
                   Chandeleur/Breton Coastal Barrier                          n      0.0                 n      0.0                  6     0.1                      12      0.1
                   East Deltaic Plain Marshes                                 1      0.0                 2      0.0               21       0.2                      49      0.7
                   xd'W. Winter Menhaden Spawning Ground                      n      0.0                 1      0.0                  n     0.0                      31      0.4









                Table IV-21. Probabilities (expressed as percent chance) of One or More Spills Greater than or Equal to 1,000 bbl, and the Estimated Number of
                               Spills (mean) Occurring and Contacting Land Segments Over the Life of the Proposed Action Within 10 Days (Central Gulf Sale 142)
                               (continued)

                                                                      Base Case                High Case                Gulfwide                      OCS Program
                Land Segment/                                          (CPA)                    (CPA)                   Import Tankering              Activities
                Environmental Resource                                Prob Mean                Prob Mean                Prob Mean                     Prob Mean


                C. Winter Menhaden Spawning Ground                    n     0.0                n     0.0               19      0.2                    26    0.3
                Eastern Deepwater Boundary                            n     0.0                n     0.0               57      0.8                    7     0.1
                  i Bend Sea rass                                     n     0.0                n     0.0                n      0.0                    n     0.0
                  orida Bay S
                               agrass Beds                            n     0.0                n     0.0                1      0.0                    n     0.0
                      ortugas                                         n     0.0                n     0.0               16      0.2                    n     0.0
                    er orida Keys                                     n     0.0                n     0.0                9      0.1                    n     0.0
                  wer orida Keys                                      n     0.0                n     0.0                9      0.1                    n     0.0
                Florida Middle Grounds                                n     0.0                n     0.0                n      0.0                    n     0.0
                Survey lock 1                                         n     0.0                n     0.0               16      0.2                    8     0.1
                Survey lock 2                                         n     0.0                1     0.0               10      0.1                    16    0.2
                Survey B ock 3                                        1     0.0                1     0.0               30      0.4                    25    0.3
                Survey Block 4                                        1     0.0                2     0.0               59      0.9                    27    0.3
                Survey Block 5                                        2     0.0                3     0.0               64      1.0                    21    0.2
                Survey Block 6                                        3     0.0                4     0.0               39      0.5                    28    0.3
                Survey Block 7                                        2     0.0                3     0.0               28      0.3                    25    0.3
                South Padre Island Coastal Barrier                    n     0.0                n     0.0                n      0.0                    n     0.0
                North Padre Island Coastal Barrier                    n     0.0                n     0.0                1      0.0                    n     0.0
                  ustang Island Coastal Barrier                       n     0.0                n     0.0                4      0.0                    2     0.0
                  t Joseph Island Coastal Barrier                     n     0.0                n     0.0                9      0.1                    2     0.0
                  atagorda Island Coastal Barrier                     n     0.0                n     0.0                6      0.1                    3     0.0
                  atagorda Peninsula Coastal Barrier                  n     0.0                n     0.0                n      0.0                    1     0.0
                  razos Headland Coastal Barrier                      n     0.0                n     0.0                3      0.0                    1     0.0
                Galveston Is./Bolivar Peninsula Coastal Barrier       n     0.0                n     0.0               22      0.3                    8     0.1
                Rollover Pass to Sabine Pass Coastal Barrier          n     0.0                n     0.0                3      0.0                    1     0.0
                Laguna Madre Sea ass Beds                             n     0.0                n     0.0                1      0.0                    n     0.0
                Corpus Christi Ba Teagrass Beds                       n     0.0                n     0.0                4      0.0                    2     0.0
                Ez,iritu Santosrataporda Seagrass Beds                n     0.0                n     0.0                6      0.1                    4     0.0
                Gd veston Seagrass eds                                n     0.0                n     0.0               22      0.3                    8     0.1
                Espiritu Santos/Matagorda Bays                        n     0.0                n     0.0                6      0.1                    4     0.0
                Galveston Ba                                          n     0.0                n     0.0               22      0.3                    8     0.1
                Texas CoastNMarshes - Central                         n     0.0                n     0.0               14      0.2                    6     0.1
                Texas Coastal Marshes - Eastern                       n     0.0                n     0.0               27      0.3                    9     0.1
                Brazoria South Padre Island Rec. Beaches              n     0.0                n     0.0                n      0.0                    n     0.0
                Padre/Mustang Rec. Beaches                            n     0.0                n     0.0                5      0.0                    2     0.0
                M
                S
                M
                M
                B









                Matagorda Isliind Rec. Beaches                        n     0.0                n     0.0                6      0.1                    3     0.0
                Matagorda Coun Rec. Beaches                           n     0.0                n     0.0                n      0.0                    1     0.0
                Brazoria County Wec. Beaches                          n     0.0                n     0.0                3      0.0                    1     0.0
                Galveston Is./Bolivar Peninsula Rec. Beaches          n     0.0                n     0.0               22      0.3                    8     0.1
                Sea Rim Rec. Beaches                                  n     0.0                n     0.0                3      0.0                    1     0  0      <
                Chenier Plain Coastal Barrier                         n     0.0                n     0.0               23      0.3                    12    0  1
                Grand Isle/Grand Terre Coastal Barrier                n     0.0                n     0.0                1      0.0                    11    0.1








               Table IV-21. Probabilities (expressed as percent chance) of One or More Spills Greater than or Equal to 1,000 bbl, and the Estimated Number of
                             Spills (mean) Occurring and Contacting Land Segments Over the Life of the Proposed Action Within 10 Days (Central Gulf
                                                                                                                                                        Sale 142) 0-A
                             (continued)

                                                                   Base Cas e              High Case                Gulfwide                     OCS Program
               Land Segment/                                        (CPA)                    (CPA)                  Import Tankering             Activities
               Environmental Resource                              Prob Mean               Prob Mean                Prob Mean                    Prob Mean

               Dauphin Island Coastal Barrier                      n     0.0               n     0.0                2     0.0                    1      0.0
               Gulf Shores Coastal Barrier                         n     0.0               n     0.0                n     0.0                    n      0.0
               Mobile Bay/Perdido Bay Seagrass Beds                n     0.0               n     0.0                3     0.0                    2      0.0
               Vermilion/Atchafalaya Bays                          n     0.0               n     0.0                n     0.0                   14      0.2
               Mobile Ba                                           n     0.0               n     0.0                3     0.0                    2      0.0
               Chenier P∈ Marshes                                n     0.0               n     0.0               Z3     0.3                   12      0.1
               Cameron Parish Rec. Beaches                         n     0.0               n     0.0               23     0.3                    6      0.1
               Fouchon Rec. Beaches                                n     0.0               n     0.0                1     0.0                   10      0.1
               Grand Isle Rec. Beaches                             n     0.0               n     0.0                1     0.0                   11      0.1
               Mississippi Mainland Rec. Beaches                   n     0.0               n     0.0                3     0.0                    3      0.0
               Dauphift'Island Rec. Beaches                        n     0.0               n     0.0                2     0.0                    1      0.0
               Gulf Shores Rec. Beaches                            n     0.0               n     0.0                n     0.0                    n      0.0
               Note: n = less than 0.5% probability;      0.0% probability: Segments with less than 0.5% probability of one or more contacts within 10 days are not
                    shown.

               Source: Price, written comm., 1991.










                                                                                              Table IV-22
                                                    Probabilities (expressed as percent chance) of One or More Spills Greater or Equal to
                                          1,000 bbl and the Estimated Number of SVills (mean@ Occurring and Cdntacting Land Segments Over the
                                                                            Life of the roposed ction Within 10 Days
                                                                                       (Western Gulf Sale 143)
                                                                              Base Case                   High Case                    GuNwide                      OCS Program
                  Land Segment/                                               (WPA)                       (WPA)                    Import Tankering                    Activities
                  Environmental Resource                                      Prob Mean                   Prob Mean                    'Prob Mean                      Prob Mean
                   1 - Cameron Tex                                                                                                     n       0.0                     n       0.0
                   2 - Willacy, Tex.
                   3 - Kenedy, Tex.                                                                                                    n       0.0                     n       0.0
                   4 - Kleberg, Tex.                                                                                                   1       0.0                     n       0.0
                   5 - Nueces, Tex., et al.                                   n      0.0                  n     0.0                    4       0.0                     2       0.0
                   6 - Aransas, Tex.                                          n      0.0                  n     0.0                    9       0.1                     2       0.0
                   7 - Calhoun, Tex.                                          n      0.0                  n     0.0                    6       0.1                     3       0.0
                   8 - Matagorda Tex.                                         n      0.0                  n     0.0                    n       0.0                     1       0.0
                   9 - Brazoria, Tex.                                                                                                  3       0.0                     1       0.0
                  10 - Galveston, Tex., et al.                                n      0.0                  1     0.0                    22      0.3                     8       0.1
                  11 - Jefferson, Tex.                                        -      -                    -     -                      3       0.0                     1       0.0
                  12 - Cameron, La.                                           -      -                    -     -                      23      0.3                     6       0.1
                  13 - Vermilion  ' La.                                       -      -                    -     -                      n       0.0                     6       0.1
                  14 - Iberia, La.                                            -      -                    -     -                      n       0.0                     6       0.1
                  15 - St. Mary, La.                                          -      -                    -     -                      n       0.0                     9       0.1
                  16 - Terrebonne La                                          -      -                    -     -                      n       0.0                     32      0.4
                  17 - Lafourche L                                            -      -                    -     -                      1       0.0                     10      0.1
                  18 - Jefferson, Ca.                                                                           -                      1       0.0                     11      0.1
                  19 - Plaquemmes La                                                                            -                      21      0.2                     54      0.8
                  20 - St. Bernard, Fa.,*et al.                                                                 -                      1       0.0                     1       0.0
                  21 - Hancock, Miss., et al.                                                                   -                      3       0.0                     3       0.0
                  22 - Mobile, Ala.                                                                             -                      2       0.0                     1       0.0
                  23 - Baldwin, Ala.                                                                            -                      n       0.0                     n       0.0
                  24 - Escambia, Fla.                                                                           -                      n       0.0                     n       0.0
                  44 - Dade, Fla.                                                                               -                      18      0.2                     n       0.0
                  45 - Broward, Fla.                                                                            -                      2       0.0                     n       0.0
                  Land                                                        1      0.0                  2     0.0                    73      1.3                     85      1.9
                  Western Deepwater Boundary                                  2      0.0                  5     0.1                    71      1.2                     30      0.4
                  Aransas Refti                                               n      0.0                  n     0.0                    4       0.0                     2       0.0
                  Tamaulipas,Texico                                           n      0.0                  n     0.0                    n       0.0                     n       0.0
                  Deepwater Bound Cen.                                        n      0.0                  n     0.0                    96      3.3                     59      0.9
                  Timbalier Bay                                               n      0.0                  n     0.0                    1       0.0                     30      0.4
                  Barataria Bay                                               n      0.0                  n     0.0                    9       0.1                     36      0.4
                  Mississippi Sound                                           n      0.0                  n     0.0                    7       0.1                     6       0.1
                  Caminada Headland                                           n      0.0                  n     0.0                    4       0.0                     21      0.2
                  West Plaquentines Coastal Barrier                           n      0.0                  n     0.0                    28      0.3                     52      0.7
                  Chandeleur/Breton Coastal Barrier                           n      0.0                  n     0.0                    6       0.1                     12      0.1
                  East Deltaic Plain Marshes                                  n      0.0                  n     0.0                    21      0.2                     49      0.7     <
                  W. Winter Menhaden Spawning Ground                          n      0.0                  n     0.0                    n       0.0                     31      0.4








                 Table IV-22. Probabilities (expressed as percent chance) of One or More Spills Greater than or Equal to 1,000 BbI and the Estimated Number of Spills
                               (mean) Occurring and Contacting Land Segments Over the Life of the Proposed Action Within 10 Days (Western Gulf Sale 143)
                               (continued)

                                                                     Base Case                High Case                  Guffwide                   OCS Program
                 Land Segment/                                        (WPA)                    (WPA)                  Import Tankering                Activities
                 Environmental Resource                              Prob Mean                Prob Mean                  Prob Mean                    Prob, Mean

                 C. Winter Menhaden Spawning Ground                  n     0.0                n     0.0                  19      0.2                  26      0.3
                 Eastern Deepwater Boundary                          n     0.0                n     0.0                  57-     0.8                   7      0.1
                               Yrass
                 ig Bend Seal,                                       n     0.0                n     0.0                   n      0.0                   n      0.0
                 orida Bay Seagrass Beds                             n     0.0                n     0.0                   1      0.0                   n      0.0
                 Xy Tortugas                                         n     0.0                n     0.0                  16      0.2                   n      0.0
                 Jpper Florida Keys                                  n     0.0                n     0.0                   9      0.1                   n      0.0
                 .ower Florida Keys                                  n     0.0                n     0.0                   9      0.1                   n      0.0
                 Florida Middle Grounds                              n     0.0                n     0.0                   n      0.0                   n      0.0
                 Survey lockl                                        n     0.0                n     0.0                  16      0.2                   8      0.1
                 Survey lock 2                                       n     0.0                n     0.0                  10      0.1                  16      0.2
                 Survey B ock 3                                      n     0.0                n     0.0                  30      0.4                  25      0.3
                 Survey Block 4                                      n     0.0                n     0.0                  59      0.9                  27      0.3
                 Survey Block 5                                      n     0.0                n     0.0                  64      1.0                  21      0.2
                 Survey Block 6                                      n     0.0                n     0.0                  39      0.5                  28      0.3
                 Survey Block 7                                      n     0.0                n     0.0                  28      0.3                  25      0.3
                 South Padre Island Coastal Barrier                  n     0.0                n     0.0                   n      0.0                   n      0.0
                 North Padre Island Coastal Barrier                  n     0.0                n     0.0                   1      0.0                   n      0.0
                 ustang Island Coastal Barrier                       n     0.0                n     0.0                   4      0.0                   2      0.0
                 L Joseph Island Coastal Barrier                     n     0.0                n     0.0                   9      0.1                   2      0.0
                 atagorda Island Coastal Barrier                     n     0.0                n     0.0                   6      0.1                   3      0.0
                 atagorda Peninsula Coastal Barrier                  n     0.0                n     0.0                   n      0.0                   1      0.0
                 razos Headland Coastal Barrier                      n     0.0                n     0.0                   3      0.0                   1      0.0
                 Galveston Is./Bolivar Peninsula Coastal Barrier     n     0.0                1     0.0                  22      0.3                   8      0.1
                 Rollover Pass to Sabine Pass Coastal Barrier        n     0.0                n     0.0                   3      0.0                   1      0.0
                 Laguna Madre Seagrass Beds                          n     0.0                n     0.0                   1      0.0                   n      0.0
                 Corpus Christi Ba -Seagrass Beds                    n     0.0                n     0.0                   4      0.0                   2      0.0
                 Espiritu Santoswatagorda Seagrass Beds              n     0.0                n     0.0                   6      0.1                   4      0.0
                 Galveston Seagrass Beds                             n     0.0                1     0.0                  22      0.3                   8      0.1
                 Espiritu Santos/Matagorda Bays                      n     0.0                n     0.0                   6      0.1                   4      0.0
                 Galveston Ba                                        n     0.0                1     0.0                  22      0.3                   8      0.1
                 Texas CoastNMarshes - Central                       n     0.0                1     0.0                  14      0.2                   6      0.1
                 Texas Coastal Marshes - Eastern                     n     0.0                1     0.0                  27      0.3                   9      0.1
                 Brazoria South Padre Island Rec. Beaches            n     0.0                n     0.0                   n      0.0                   n      0.0
                 Padre/Mustang Rec. Beaches                          n     0.0                n     0.0                   5      0.0                   2      0.0
                 Matagorda IsIdnd Rec. Beaches                       n     0.0                n     0.0                   6      0.1                   3      0.0
                 Matagorda County Rec. Beaches                       n     0.0                n     0.0                   n      0.0                   1      0.0
                 Brazoha County Rec. Beaches                         n     0.0                n     0.0                   3      0.0                   1      0.0
                 Galveston Is./Bolivar Peninsula Rec. Beaches        n     0.0                1     0.0                  22      0.3                   8      0.1
                 Sea Rim Rec. Beaches                                n     0.0                n     0.0                   3      0.0                   1      0.0
                 Chenier Plain Coastal Barrier                       n     0.0                n     0.0                  23      0.3                  12      0.1
                 Grand Isle/Grand Terre Coastal Barrier              n     0.0                n     0.0                   1      0.0                  11      0.1
                 M
                 S
                 M
                 M
                 B








                Table IV-22. Probabilities (expressed as percent chance) of One or More Spills Greater than or Equal to 1,000 Bbl and the Estimated Number of Spills
                             (mean) Occurring and Contacting Land Segments Over the Life of the Proposed Action Within 10 Days (Western Gulf Sale 143)
                             (continued)

                                                                    Base Case               High Case                 Gultwide                   OCS Program
                Land Segment/                                        (WPA)                   (WPA)                  Import Tankering              Activities
                Environmental Resource                              Prob Mean               Prob Mean                Prob Mean                    Prob Mean


                Daunhm* Island Coastal Barrier                      n     0.0               n     0.0                  2      0.0                   1     0.0
                GulfShores Coastal Barrier                          n     0.0               n     0.0                  n      0.0                   n     0.0
                Mobile Bay/Perdido Bay Seagrass Beds                n     0.0               n     0.0                  3      0.0                   2     0.0
                Vermilion/Atchafalaya Bays                          n     0.0               n     0.0                  n      0.0                 14      0.2
                Mobile Ba                                           n     0.0               n     0.0                  3      0.0                   2     0.0
                Chenier PKin Marshes                                n     0.0               n     0.0                  23     0.3                 12      0.1
                Cameron Parish Rec. Beaches                         n     0.0               n     0.0                  23     0.3                   6     0.1
                Fouchon Rec. Beaches                                n     0.0               n     0.0                  1      0.0                 10      0.1
                Grand Isle Rec. Beaches                             n     0.0               n     0.0                  1      0.0                 11      0.1
                Mississippi Mainland Rec. Beaches                   n     0.0               n     0.0                  3      0.0                   3     0.0
                Dauphifi-Island Rec. Beaches                        n     0.0               n     0.0                  2      0.0                   1     0.0
                Gulf Shores Rec. Beaches                            n     0.0               n     0.0                  n      0.0                   n     0.0
                Note: n = less than 0.5% probability;      0.0% probability. Segments with less than 0.5% probability of one or more contacts within 10 days are not
                      shown.

                Source: Price, written comm., 1991.










                 IV-126



                      The following recreational beach environmental resources were combined to give statewide recreational
                 beach values:


                              Texas Rec. Beaches                                 Brazos/South Padre Is. Rec. Beaches
                                  Padre Is. National Seashore/Mustang Is.
                                   Rec. Beaches
                                  Matagorda Is. Rec. Beaches
                                  Matagorda County Rec. Beaches
                                  Brazoria County Rec. Beaches
                                  Galveston Is./Bolivar Peninsula Rec. Beaches
                                  Sea Rim Rec. Beaches


                              Louisiana Rec. Beaches                             Cameron Parish Rec. Beaches
                                  Fourchon Rec. Beaches
                                  Grand Isle Rec. Beaches


                              Mississippi Rec. Beaches                           Gulf Is. National Seashore Rec. Beaches
                                  Mississippi Mainland Rec. Beaches

                              Alabama Rec. Beaches                               Dauphin Is. Rec. Beaches
                                  Gulf Shores Rec. Beaches


                              Florida Rec. Beaches                               Emerald Coast Rec. Beaches,
                                  Panama City Beach Rec. Beaches
                                  St. Joseph Spit Rec. Beaches
                                  Franklin County Rec. Beaches
                                  Central Florida Rec. Beaches


                     For each planning area, the appropriate table shows the risks from several sources of off, both from within
                 and from outside the planning area. These include the proposed volume assumed to be discovered and
                 produced as a result of this sale, the Base Case, and a High Case for the proposal. Also, for each planning
                 area, the occurrence and contact probabilities of an oil spill from imports and from a Gulfwide perspective
                 were calculated and presented.
                     The 3-, 10-, and 30-day increments were selected to represent three critical phases of a spill. Because of
                 the characteristics of the crude oil expected to be produced in the Gulf and because the values for "within 10
                 days" necessarily include the values for the "within 3 days" category, most analyses in this EIS focus on the
                 10-day values, considering this a conservative approach. In the OSRA run for the Base Case, no land segment
                 shows a detectable chance of a spill occurring and contacting it within 3 days. No spills were estimated to occur
                 and contact any of the land segments in the Western Gulf as a result of the Base Case. In all cases, the
                 probabilities (expressed as a percentage) and mean values are lower than those for 10 days. For the 30-day
                 increment, two land segments in the Central Gulf have detectable values. These land segments are shown
                 below.


                                                                   Central Gulf


                              Land Segment                                       Prob.                         Mean


                              16-Terrebonne, La.                                     2                          0.0
                              19-Plaquemines, La.                                    2                          0.0











                                                                                                                           IV-127
                4. Oil Spill Preventidn

                    Oil and gas operations conducted on the Gulf of Mexico OCS are subject to many requirements with
                regard to providing safety for personnel and the prevention of pollution. The basic government document that
                addresses these requirements are those regulations contained under 30 CFR 250. Within 30 CFR 250 there
                are many Subparts addressing specific aspects of these operations, such as Subparts D, E, F, H, and J, which
                address drilling, completion, workover, production, and pipelines, respectively. Subpart C outlines various
                procedures and equipment for containment and control of oil spills on drilling and production facilities. In
                addition, the American Petroleum Institute (API) has published numerous technical specifications and
                Recommended Practices (RP), which have been incorporated by reference into the aforementioned regulations.
                The most prominent of these specifications and practices is API RP 14C, which provides design and installation
                criteria for surface safety systems on offshore platforms.

                Production Operations

                    The purpose of a platform surface safety system is to protect personnel, the environment, and the facility
                from threats to safety caused by the production process. The major objective of the safety system is to prevent
                the release of hydrocarbons from the process and to minimize the adverse effects of such releases if they oecur.
                The overall objectives may be enumerated as follows

                        (a)     prevent undesirable events that could lead to a release of hydrocarbons;

                        (b)     shut in the process or affected part of the process to stop the flow of hydrocarbons to
                                a leak or overflow if it occurs;

                        (c)     accumulate and recover hydrocarbon liquids and disperse gases that escape from the
                                process; and

                        (d)     shut in the process in the event of a fire.

                    The platform safety system provides two levels of protection to prevent or minimize the effects of an
                equipment failure within the process. The two levels of protection are independent of and in addition to the
                control devices used in the normal process operation. In general, these two levels are provided by functionally
                different types of safety devices for a wider spectrum of coverage. These protective measures have been
                common industry practices and proven through many years of experience.
                    The majority of threats to safety on a production platform are caused by the release of hydrocarbons.
                Thus, the analysis and design of a production platform safety system must focus on preventing such releases
                by stopping the flow of hydrocarbons to a leak and by minimizing the effects of hydrocarbons that are released.
                To accomplish this, safety systems utilize protection concepts to prevent the occurrence of undesirable events.
                An undesirable event is an adverse occurrence in a process component which poses a threat to safety and may
                result in the accidental release of hydrocarbons.
                    In a production safety system these undesirable events are detected by various types of sensors that initiate
                shutdown action to prevent or limit the release of hydrocarbons from a well or process vessel. These sensors
                can be installed on the specific well or process vessel or as part of the Emergency Support System (ESS). The
                ESS includes


                        (a)     the combustible gas detection system to sense the presence of escaped hydrocarbons
                                and to initiate alarms and platform shutdown before gas concentrations reach the
                                lower explosive limit;










                IV-128

                (b)     the containment system to collect escaped liquid hydrocarbons and to initiate platform
                        shutdown;

                (c)     the fire loop system to sense the heat of a fire and to initiate platform shutdown;

                (d)     the Emergency Shutdown System (ESD) to provide a method to manually initiate
                        platform shut down by personnel observing abnormal conditions or undesirable events;
                        and

                (e)     the subsurface safety valves (SSSV), which may be self-actuated or actuated by an
                        ESD system and/or a fire loop system, located within the wellbore of every well.

            The undesirable events that are addressed in the design of a production platform safety system with regard
       to pollution prevention are overpressure, leak, liquid overflow, gas blowby, and underpressure.

       Overpressure

            Overpressure is pressure in a process component in excess of the normal operating pressure range. The
       primary protection utilized to detect an overpressure condition is a high-pressure sensor (PSH). The PSH is
       set at a pressure no higher than 15 percent above the highest operating pressure of the pressure component.
       If an abnormal condition occurs and pressure within this component reaches the PSH set pressure, it invokes
       shut down of the incoming valve. In cases of primary failure, secondary protection is provided by a pressure
       relief valve (PSV). If the primary protection (PSH) was unable to detect or initiate shut down, then the
       excessive pressure would be relieved through the PSV to a relief containment system.

       Leak


            A leak is the accidental escape of fluids from a process component to the atmosphere. The primary
       protection from leaks of a significant rate creating an abnormal operating condition within a pressure
       component is provided by a low-pressure sensor (PSL) and a flow safety valve (FSV). The PSL is set at a
       pressure no lower than 15 percent below the lowest operating pressure of the pressure component. If a
       significant leak were to incur and the pressure within this component dropped to the PSL set pressure, it would
       invoke shut down of the incoming valve. An FSV is basically a valve fitted with a flapper gate, allowing
       production flow in only one direction thereby minimizing backflow of downstream production to flow to the
       leak. Secondary protection is provided by the ESS. Ile gas detection system on a production platform would
       sense and initiate shut in before a leak became significant

       Liquid Oveiflow

            Liquid overflow is the discharge of liquids from a process component through a gas or vapor outlet. The
       primary protection for liquid overflow is provided by a level sensor high (LSH). If an abnormal high liquid
       level occurred within a process vessel, then activation of this sensor would shut off production to the process
       component.
            Secondary protection from liquid overflow to the atmosphere is provided by the ESS, as in the case of a
       leak occurrence discussed previously. Additionally, secondary protection from liquid overflow to downstream
       components would be provided by downstream safety devices on those components.

       Gas Blowby

            Gas blowby is the discharge of gas from a process component through a liquid outlet. The primary
       protection from gas blowby is provided by a level sensor low (LSL). If an abnormally low liquid level occurred











                                                                                                                             IV-129

                within a process component, then this sensor would effect shut in of incoming production to the vessel.
                Secondary protection is provided by safety devices on the downstream process component.

                Underpressure

                    "Underpressure" is pressure in a process component that is less than the design collapse pressure. This
                undesirable event is generally experienced within stock tanks where production is transferred by pumps to
                departing pipelines. The pumps, in transferring production, impose a vacuum on the tank. The primary
                protection for underpressure is the installation of an adequate vent system. Secondary protection is provided
                by an additional vent or a pressure-vacuum safety device. This device serves to protect the component from
                excessive pressures or a vacuum.

                Drilling and Workover Operations

                    With respect to drilling operations, control of well formation fluids (off, gas, and water) is of main concern.
                Primary and secondary levels of protection are implemented to maintain control of the well while drilling. The
                primary level of control is provided by the hydrostatic pressure of the drilling mud. Control is maintained by
                the circulation of properly weighted mud. The weight of the mud is adjusted to provide a sufficient hydrostatic
                margin over the estimated formation pressure. This hydrostatic margin allows for safe drilling without taking
                a "kick" from drilled formations. Various rig equipment monitors the mud system to ensure that this margin
                is maintained and that the system is working as designed. Monitoring of the mud system is accomplished
                through the use of mud pit indicators (gain or loss), flow indicators, and gas detection. When this equipment
                detects pit gain, flow, or the presence of gas, the secondary level of control can be initiated. This second level
                of control is comprised of the blowout preventer (BOP), rig mud pumps, and the choke manifold. This
                equipment allows for control of the well when formation pressure exceeds the hydrostatic pressure of the mud.
                The BOP is composed of a series or a stack of rams, which are designed to seal the wellbore at the surface
                to prevent flow. The stack includes at least two rams equipped to close on drill pipe, one blind ram, and one
                annular type--all of which can be hydraulically operated from remote stations on the rig. Once the well is shut
                in, the mud can be weighted up and pumped downhole with the rig pumps. While the mud is pumped, the
                hydrostatic pressure on the formation is maintained utilizing the choke system. Control of the well is
                reestablished once the weighted mud is circulated throughout the well.
                    This two-tiered level of control has been well proven through many years of drilling. This is illustrated by
                the extremely low blowout occurrence record.

                Developing Technologies

                    In the interest of improving safety and oil-spill prevention, several new approaches are being developed
                to improve current technology. Much of the new technology is in the area of Systems Control and Data
                Acquisition. These systems are capable of computer monitoring numerous points for abnormal pressure,
                temperature, or volume conditions. Additionally, these systems can provide offshore operators a means of
                remote monitoring and shut in of unmanned facilities. Another technology being developed is the remote video
                monitoring of a facility utilizing remote-control video cameras. This technology could provide an operator with
                a means of remote-control visual inspection of an unmanned facility. In regard to drilling technology, the
                measurement while drilling (MWD) systems currently being implemented provide the driller with a nearly
                instantaneous reading of wellbore pressure and an indication of potential kicks. Systems such as these allow
                the driller to react quicker to blowout possibilities. New approaches are constantly being analyzed for
                improving the prevention of accidental hydrocarbon releases.











                 IV-130
                 5. Oil Spill Contingency Planning and Response

                     The ability to prevent, contain, and clean up oil spills--already an area of concern and f6ms for MMS, the
                 off industry, and the general public before the March 24, 1989, Erxon Valdez grounding on Bli,gh Reef in Prince
                 William Sound, Alaska--has been an even greater area of concern and focus after the recent rash of tanker-spill
                 incidents occurring in U.S. waters nationwide. Although tanker spills are not a result of acdvities conducted
                 in association with OCS oil and gas development, their occurrence has shown that existing government and
                 industry cleanup operations were ineffective in containing large oil spills. A report to the President on the
                 Alaskan spill that was prepared by the National Response Team (NRT) stated, "The lack of necessary
                 preparedness for oil spills in Prince William Sound (Alaska) and the inadequate response actions that resulted
                 mandate improvements in the way the nation plans for and reacts to oil spills. . ." (Skinner and Reilly, 1989).
                 As a means of addressing this issue, the Oil Pollution Act of 1990 (OPA) was enacted in August 1990. On
                 October 18, 1991, the President signed the Executive Order delegating the provisions of OPA to various
                 departments and agencies within the U.S. Government, including the USCG, USEPA, NOAA, and DOI.
                 Pending implementation of the provisions of the Act, the MMS spill-response program as described in this
                 section is expected to undergo further assessment and change.

                 a. Responsibility and Authority

                     The President (through the USCG) must ensure the removal of a discharge under the recently enacted
                 Off Pollution Act of 1990. Never before in the history of oil-spill response has the Federal Government had
                 as much authority over the cleanup of an oil spill. The USCG is responsible for ensuring an "effective and
                 immediate removal of a discharge"into water (OPA, Title IV, Subtitle B, Sec. 4201) This can be accomplished
                 in a number of ways; the USCG can either conduct (and fund) the cleanup itself and request reimbursement
                 from the spills, direct others as to how to cleanup the spill, or monitor the cleanup activities.
                     Coordination among the USCG, MMS, and industry has historically been required in order for an effective
                 spill response to an OCS-related operation discharge to take place. A Memorandum of Understanding (MOU)
                 dated August 29, 1989, outlines the responsibilities between USCG and MMS. The Minerals Management
                 Service is responsible for spill abatement and mitigation measures on or within 500 in of a platform, drilling
                 rig, or other OCS facility. The USCG has the ultimate responsibility for ensuring that the oil-spill incident is
                 effectively cleaned up. The OCS operators are required to prevent pollution, inspect and maintain oil-spill
                 response equipment, develop oil-spill contingency plans, and conduct drills and training for oil-spill response
                 personnel. Section I.B.3.d.(3) further outlines industry requirements for environmental safeguards.

                 b. Oil Spill Contingency Planning

                     Oil spill contingency plans (OSCP's) provide spill response guidelines to responsible parties when a spill
                 occurs. These plans provide for the preplanning, management, and coordinationof all of the operations at the
                 scene of a spill, as well as of the communications between involved parties at the time of a spill. The goal of
                 the development of such plans is having the ability to provide an efficient, coordinated, and effective response
                 to oil spins.
                     The Federal Government's statutory requirements for contingency planning are outlined in the Federal
                 Water Pollution Control Act (commonly called the Clean Water Act), as amended by the Oil Pollution Act of
                 1990, and the Comprehensive Environmental Response, Compensation, and Liability Act of 1.980 (CERCLA).
                 The National Oil and Hazardous Substance Pollution Contingency Plan (commonly called the National
                 Contingency Plan) calls for the establishment of a system of Federal regional plans (Regional Contingency
                 Plans, or RCP's) that would fulfill the same requirements on a regional level as the National Contingency Plan.
                     The Oil Pollution Act of 1990 requires that the National Contingency Plan be revised and republished to
                 include the amendments made by this Act. This monumental effort is ongoing. Provisions ofthis Act require,
                 in part, that the National Contingency Plan contain (1) an assignment of duties among Federal, State, and
                 local agencies; (2) an identification, procurement, maintenance, and storage of equipmentand supplies; (3)











                                                                                                                            IV-131

               designation of USCG strike teams consisting of personnel, equipment, and a detailed oil and hazardous
               substance pollution and prevention plan; (4) a system of surveillance and notice to safeguard against and
               ensure the early notification of discharges of off; (5) establishment of a national center to coordinate and direct
               operations in carrying out the Plan; (6) procedures and techniques to be employed in identifying, containing,
               dispersing, and removing discharges; (7) a State coordinated dispersant use plan; (8) a system whereby a State
               can act to remove a spill or be reimbursed by the Oil Spill Liability Trust Fund; (9) designation of the Federal
               On-Scene Coordinator for each area for which an Area-Contingency Plan is prepared; and (10) a fish and
               wildlife response plan, developed in consultation with the FWS, NOAA, and other interested parties for the
               immediate and effective protection, rescue, and rehabilitation of fish, wildlife, or their habitat that are harmed
               or may be jeopardized by a discharge.
                    The OPA also calls for the designation of areas for which Area Committees win be established and for
               which Area Contingency Plans will be required. The designated coastal areas for which Area Committees will
               be established are expected to coincide with the USCG Captain of the Port boundaries. Inland areas will be
               established under joint concurrence between USCG and USEPA. Although existing Captain of the Port
               Contingency Plans are available, they will require extensive revision as they currently do not contain the level
               of planning required. Some of the content requirements for Area Contingency Plans require that (1) when
               implemented in conjunction with the National Contingency Plan provisions an Area Plan would be adequate
               to remove a worst case discharge; (2) the area covered by the plan including areas of specific economic or
               environmental importance are discussed; (3) the procedures for obtaining an expedited decision regarding the
               use of dispersants, are described; and (4) details regarding how the Plan is integrated into other Area Plans and
               the vessel, offshore facility, and onshore facility response plans, also required pursuant to this Act, are
               provided. Operators of a tank vessel or facility are also required to submit response plans sufficient to respond,
               to the maximum extent possible, to a worst case discharge. The responsible agencies have a target date of
               August 1992 to issue regulations for tank vessel and facility response plans.
                    The following discussion outlines the planning requirements and procedures for responding to a discharge
               that are currently in effect and that will remain in effect until the implementation of the revised contingency
               planning provisions enacted by the Oil Pollution Act of 1990. Significant changes to these current contingency
               planning procedures are not, however, expected.
                    The two Regional Contingency Plans that operate in the Gulf cover the Regional Response Teams for
               USEPA Regions IV and VI. When the spill occurs in coastal and offshore navigable waters of the United
               States, the USCG Captains-of-the-Port are designated as the On-Scene Coordinators (OSC's). Duties of the
               OSC include notifying the responsible party of the spill, encouraging the party to undertake proper
               countermeasures to mitigate the effect, directing and monitoring cleanup progress, and providing advice and
               counsel to the spiller as necessary. To provide support to the OSC, a Regional Response Team, which consists
               of representatives from Federal agencies as well as representatives from State and local agencies, has been
               established. The Regional Response Team serves as a regional body for oil spill preparedness planning and
               can be convened at the request of an OSC for coordination and advice during a spill incident The DOI is a
               member of the Regional Response Team. The DOI assists the OSC at the time of a spill by providing special
               expertise relating to land management, fish and wildlife habitat, and water resources management. A Scientific
               Support Coordinator is provided by NOAA to coordinate and develop scientific response information as
               needed. The National Contingency Plan also requires Federal local plans (Local Contingency Plans) for areas
               in which the Coast Guard provides the predesignated OSC's. Each level of planning is designed to contain
               more site-specific information to allow the USCG to quickly organize an effective response to a pollution
               incident, if necessary.
                    During an OCS operations-related spill event, the U.S. Coast Guard's OSC will make every reasonable
               effort to have the operator voluntarily and promptly clean up spilled oil. Per regulation requirement, it is the
               responsibility of all OCS off industry operators to take immediate corrective action when an off spill has
               occurred. Provisions for authority in removing discharges are further discussed in Section IV.C.6.a.
                    To effectively accomplish off spill containment and removal actions, the MMS requires that all Exploration
               Plans (EP), Development and Production Plans (DPP), and Development Operations Coordination Documents
               (DOCD) be accompanied by an OSCP. In order to facilitate this requirement in the Gulf of Mexico region
               in a practical manner, it is expedient for each OCS operator to submit for approval a regional OSCP that










                  IV-132

                  covers all of their operations in the Gulf of Mexico. The approved regional OSCP is then referenced when
                  EP's and DOCD's are submitted. However, the operator may elect or may be required by MMS to include
                  a site-specific OSCP in a EP or DOCD when the approved regional OSCP does not provide adequate oil spill
                  protection or when lease stipulations for leases in the Eastern Gulf of Mexico require response capabilities
                  beyond those described in the operator's approved regional OSCP.
                      The OCS operators are required to prepare OSCP's in accordance with the requirements of 30 CFR
                  250.42. However, since OCS operators in the Gulf of Mexico region prepare regional OSCP's, the MMS has
                  issued a Letter to Lessees (LTL) dated February 1, 1989, which outlines the requirements for regional OSCP's.
                  In addition, LTL:s dated October 12, 1988; September 5, 1989; and November 4, 1991, were issued. These
                  LTL's list the off spill information that must accompany every EP or DOCD when the EP or DOCD references
                  an approved regional OSCP. This information includes (1) an identification of the pr[mary location of
                  containment and removal equipment; (2) an estimation of the individual times for procurement of the
                  equipment, the equipment transportation vessel, and the personnel to load and operate the equipment as wen
                  as equipment load-out, travel time to the deployment site, and equipment deployment; and (3) a discussion
                  that identifies the zones that appropriate and available trajectory analysis indicate may be irnpacted by an oil
                  spill, the environmentally sensitive resources and areas within the impact zones, and the strategies to be used
                  to protect these resources from oil spills. Site-specific OSCP's are prepared in accordance with the
                  requirements of 30 CFR 250.42 and, in addition, address those items that the MMS has identified as necessary
                  or those that are required by lease stipulation.
                      Besides the Federal Government and private industry, there are contingency plans developed at the State
                  and local authority levels. The States of Florida, Texas, Alabama, and Mississippi have oil and hazardous
                  substances pollution contingency plans for their coastal areas. The State of Louisiana recently passed the Oil
                  Spill Prevention Response Act, which requires the State's appointed oil-spill response coordinators to develop
                  a statewide oil-spill prevention and response plan. This plan shall be fully operational no later than one year
                  after the latest effective date of the area and regional contingency plans designated for Louisiana pursuant to
                  Federal law.
                      At the time of a spill on the OCS, a network of contingency plans is put into effect. The provisions of the
                  Oil Pollution Act of 1990 will not alter this basic procedure; however, the existing policies may change
                  somewhat with the implementation of the provisions of the Act. Generally, if a spill results from an oil and
                  gas facility, an operator would notify the National Response Center, which was established under the auspices
                  of the National Contingency Plan; the MMS, Gulf of Mexico OCS Region; and his oil spill response
                  coordinator, who may activate the operator's oil spill response operating team. At this time, equipment and
                  manpower would be mobilized, if deemed necessary.             The Local Contingency Plan of the closest
                  Captain-of-the-Port (the OSC) would also be activated. At the request of the OSC, or if the spill crosses
                  regional boundaries or poses a substantial threat to the environment, the Regional Response Team would be
                  activated.


                  Review of Contingency Plans

                      The Federal Government's current network of contingency plans as outlined above is reviewed through
                  two mechanisms. Draft National and Regional Contingency Plans are published in the Federal Register for an
                  appropriate time period to allow review of the plans by all interested parties. All members of the Regional
                  Response Team are given an opportunity to review the draft plans to ensure that the plans recognize and
                  integrate their agency's responsibilities. Through the DOI's Regional Response Team member, MMS can
                  provide comments on Regional and Local Contingency Plans to assure that the plans conform with MMS
                  policies and procedures and that the notification process addresses MMS responsibilities :regarding off-spill
                  response planning.
                      The OCS oil industry's off spill contingency plans, as well as the supplemental information submitted with
                  EP's or DOCD's, are reviewed by MMS. This review attempts to ensure that an operator's identified response
                  time is reasonable, accurate, and sufficient to protect the adjacent environmental resources. Response times
                  are further reviewed to determine whether they include sufficient time for the procurement of a vessel, for
                  load-up and mobilization of cleanup equipment, and for transportation and deployment of the equipment.











                                                                                                                           IV-133

                 Based on the results of this review, it is determined whether the primary oil-spill response equipment location
                 identified by the operator is appropriate for the subject plan and whether the projected response time allows
                 sufficient containment/cleanup time prior to a spin potentially hitting the shoreline.
                     If the analysis indicates that a potential spill could possibly contact the shoreline in an environmentally
                 sensitive area prior to the operator reaching the spin site and/or without allowing sufficient time for cleanup,
                 the operator's response would be required to be reduced if possible; and/or as a condition of plan approval,
                 the operator would be required to be capable of implementing the appropriate shoreline oil-spill protection
                 methodology identified or referenced in their EP or DOCD to protect those resources that potentially would
                 be impacted within a time period designated by this office.
                     Section VII of the MOU between the MMS and the USCG concerning the regulation of activities and
                 facilities on the Outer Continental Shelf of the U.S., as amended in August 1989, sets up a mechanism by which
                 coordination of an oil spill contingency plan review will be handled between the USCG and the MMS. In
                 response to this MOU, the USCG's Eighth Coast Guard District is provided a copy of all MMS required
                 OSCP's submitted for the Gulf of Mexico in order that a library of these plans is available to the USCG as a
                 guide to the planned action to be taken by these facilities in the event of a spill.

                 c. Spill Response Training/Drills

                     Containment and cleanup operations are labor intensive due to the complexity of the environment they
                 are conducted in and the constant monitoring/planning efforts associated with these types of operations. It is
                 therefore essential that personnel be well trained in the use of the equipment and in the methodology of spin
                 containment and cleanup. The MMS addresses this training by requiring through regulation (30 CFR 250.43)
                 that the lessee ensures that the oil-spill response operating team is provided with annual hands-on training
                 classes in the deployment and operation of pollution-control equipment Those responsible for supervising the
                 off-spill response operations are required to be trained in directing the deployment and the use of all response
                 equipment.
                     Drills for familiarization with pollution-control equipment and operational procedures are required to be
                 held when equipment is initially placed and thereafter on an annual basis by the lessee or his contractor. The
                 personnel identified as the oil-spill response operating team in the OSCP are required to participate in these
                 drills. The drills are required to simulate conditions in the area of operations and include the deployment and
                 operation of the equipment Records of these drills are required to be maintained for 2 years. The MMS,
                 Gulf of Mexico OCS Region, requires that these drills result in the deployment and operation of each piece
                 of oil spin equipment maintained by Clean Gulf Associates (CGA) at least once every 4 years and that each
                 oil-spill response team participate in enough exercises such that they win have deployed every type of
                 pollution-control equipment maintained by CGA at lease once every 4 years. As lessees generally depend on
                 contract employees for their oil-spill response operation team members, the number of drills and training
                 classes required annually to accommodate all of the OCS lessees results in the contract personnel participating
                 in several drills and training classes within the annual timeframe. The MMS may initiate unscheduled drills
                 and may require an increase in the frequency or a change in the locations of the drills, equipment to be
                 deployed, or deployment procedures and strategies.
                     The MMS, Gulf of Mexico OCS Region, has recently implemented a program to conduct unscheduled drills
                 of five or six randomly selected operators each year. The various drills include different stages of deployment
                 of equipment and personnel. The four types of drills developed by the MMS for use in the Gulf of Mexico
                 include (1) unannounced drills with equipment mobilization only, (2) unannounced drills with equipment
                 mobilization and deployment, (3) spot"Table Top"driffs, and (4) announced"Table Top"simulations of a large
                 oil spin. A written report of each unannounced drill will be required to be submitted to MMS within 15 days
                 of the conclusion of the unannounced drill. The MMS evaluates the results of these drills and advises the
                 lessee of any necessary changes in response equipment, pro_Wdures, or strategies.
                     As of November 1991, MMS has conducted 10 unannounced drills in the Gulf of Mexico of randomly
                 selected operators and offshore locations ranging from Florida to Louisiana. In all instances, a team of MMS
                 officials initiated the drills and monitored the timing and actions taken by various company officials at several
                 key locations. Although most of the drills were initiated early in the day, one drill held February 1, 1990,
                 was conducted as a night exercise. Varying scenarios were utilized ranging from a simulated 200-bbi diesel fuel










                  IV-134

                  spill from a storage tank in the Destin Dome area that resulted in onsite equipment deployment to a simulated
                  1,000-bbl storage tank rupture combined with a 600-bbl/hr pipeline spill some 62 mi south of New Orleans that
                  resulted in a combination of equipment mobilization and simulated table-top exercises. After each drill,
                  recommendations for improvement were provided to the participating operator by MMS. While each exercise
                  identified some areas that could be improved, the Gulf of Mexico Regional Director for MMS indicated that
                  each company's response effort was generally well executed.
                      Off-spill responders are also required, through the National Contingency Plan (40 CFR 300) effective April.
                  19, 1990, to adhere to the training and safety requirements outlined in the U.S. Department of Labor,
                  Occupational Safety and Health Administration's (OSHA) Hazardous Waste Operations and Emergency
                  Response regulations at 29 CFR 1910.120. Although OSHA has specifically decided that petroleum products
                  and gases are covered by 29 CFR 1910.120, questions have been raised concerning the jinterpretation and
                  implementation of these regulations for various oil-spill response conditions. Effective April 13, 1990, the
                  OSHA requirements generally provide that spill responders, such as the equipment operators and general
                  laborers, having a potential for minimal exposure to a hazardous substance are required to have 24 hours of
                  initial off-spill response instruction and 8 hours of actual field experience. Those spill responders having
                  potential exposure to a hazardous substance at levels exceeding the permissible exposure limits (generally, those
                  situations requiring the use of a respirator and protective clothing) are required to have .40 hours of initial
                  training off site and 24 hours of actual field experience. Onsite management and supervisors are required to
                  receive the same amount of training as the equipment operators and general laborers, with the addition of 8
                  hours of specialized training in hazardous waste management Eight hours of annual refresher training is
                  required of both general employees and managers. The OSHA regulations include provisions that would relax
                  the training requirements in emergency response situations; however, there is some confusion over the
                  interpretation of the distinction between an emergency response situation and a post-ernergency response
                  situation at this time.

                  d. Equipment Response and Capability

                  (1) Equipment Locations

                      In the Gulf of Mexico region, oil-spill response equipment, identified in each operator's regional oil spill
                  contingency plans, is generally maintained at nine strategically located onshore bases by the oil industry
                  cooperative, CGA (Table IV-23). This equipment is currently the primary equipment used to respond to an
                  oil spill associated with OCS operations. However, upon the finalization of CGA!s identified vessel concept,
                  equipped and dedicated vessels will be available at four strategic offshore locations in the Gulf for rapid initial
                  response. In addition,when there is drilling activity in the EPA, oil-spill equipment may be strategically located
                  at the rig site or at other staging leases (e.g., Panama City). All MMS approved OSCP`s are required to
                  contain an inventory of backup equipment or sources that are available locally, regionally, or through contract
                  to augment the initial response equipment.
                      Although the CGA equipment is acquired and maintained for use by member companies, it is also
                  available to nonmembers for a scheduled fee. Table IV-23 also identifies the types of equipment stockpiled
                  at the nine onshore bases. All CGA bases have offshore skimmer systems known as Fast Response Systems
                  (FRS). The High-Volume Open Sea Skimmer System (HOSS) barge is maintained at the Grand Isle base in
                  coastal Louisiana because of this base's proximity to a large number of off-related activities. :Further discussion
                  of this spill-response equipment is provided in Section IV.C.6.d.(2). Other types of equipment strategically sited
                  at CGA bases throughout the Gulf of Mexico include boat and helicopter spray systems, communications
                  equipment, and 50-bbl oil storage barges.
                      The off industry can also contract for cleanup with an extensive number of independent spill-cleanup
                  contractors and industry cooperatives located throughout the Gulf Coast. The number of companies included
                  in the Marine Industry Group's Oil Spill Response manuals that have various pieces of available equipment
                  are listed by State in Table IV-24. It should be noted that, due to the recent equipment acquisitions made by
                  the local Gulf states, the Marine Spill Response Corporation, and other local cooperatives that are not included
                  in Table IV-24, the information provided in this table under represents the current Gulf equipment inventory.
                  Details of these recent equipment acquisitions will be added when the national inventory of spill-response
























                                                                                                                              Table IV-23

                                                                                                                  CGA!s, Oil Response Equipment'
                                                                                                                                                                 Surface                          Bird
                                                    Offshore                   Coastal                Offshore          Shallow Water                           Collecting Chemical               Care          Identified
                                                     Booms                     Booms                 Skimmers          SWmer Vessels           Sorbents          Agents DisMrsants             F4uipment         Vessels'

                        Texas
                        Galveston                       x                                                 x                                        x                x            x                  x
                        Port Aransas                    x                         x                       x                                        x                x            x                  x
                        Louisiana
                        Cameron                         x                                                 x
                        Intracoastal City               x                                                 x                                        x                x                               x
                        Houma                           x                                                 x                    x
                        Grand Isle2                     x                         x                       x                    x                   x                x            x                  x
                        Venice                          x                         x                       x                    x                   x                x            x                  x
                        AJabama
                        Theodore                        x                                                 x
                        Florida
                        Panama City'                    x                                                 x                                        x                x            x                  x
                        Offshore
                        West Cameron 71                 x                                                 x                                                                                                          x
                        South Marsh Island 240          x                                                 x                                                                                                          x
                        South Timbalier 26              x                                                 x                                                                                                          x

                        'As of May 1990.
                        2Main base.
                        3When there is a drilling activity in the EPA, equipment is strategically located at nearby offshore staging bases; for example, Panama City. When there is no EPA drilling, the equipment is stored in Houma,
                        Louisiana.
                        4Identified vessels are Field Utility Boats on the payroll of CGA members. The boats are equipped with skimmers and boom and two extra personnel. They will be released by the operator to respond to CGA
                        member's spilL

                        Source: CGA, 1991.






























                                                                                              Table IV-24

                                                     Number of Oil Spill Cleanup Contractors/Operators by State Stocking Various Cleanup Equipment

                                                                                                                                           Surface                      Bird
                                          Offshore             Inland/Coastal         Offshore            Inshore                         Collecting Chemical           Care
                                           Booms                  Booms              Skimmers            Skimmers          Sorbents        Agents DisRgrsants        Eguipment

               Texas                          5                      27                   1                 13                12              2           4               1
               Louisiana                      4                      16                   1                  8                9               1           1               4
               Mississippi                    0                      0                    0                  0                0               0           0               0
               Alabama                        2                      6                    0                  2                1               0           0               0
               Florida                        8                      25                   0                 14                9               7           2               0

               Source: Marine Industry Group, 1991.











                                                                                                                         IV-137

                equipment is in place. The task of keeping a national inventory of spill-response equipment has been delegated
                to the USCG National Response Unit, renamed the National Strike Force Coordination Center (NSFCC),
                located in Elizabeth City, North Carolina, in response to the mandates of OPA. This inventory will replace
                the U.S. Coast Guard SKIM inventory initiated in 1978 and ceased in the early 1980's. Besides the equipment
                operated by numerous contractors, coastal booms and skimmers are housed near refineries and other oil and
                chemical industry operations to respond to spills that may occur from their own facilities. For example, in 1988
                there were 16 onshore oil companies maintaining coastal booms at their facilities. One of the most extensive
                stockpiles of equipment, particularly open-ocean cleanup equipment, is maintained by the Louisiana Offshore
                Oil Port (LOOP) located at Port Fourchon, Louisiana. Discussions are ongoing between CGA, through
                Haliburton Services, and LOOP towards an agreement to potentially share equipment in the event of a spill.
                    Historically, if the Coast Guard OSC determines that the OCS operator responsible for the spill is not
                taking appropriate response measures, the OSC may hire a cleanup contractor to conduct the spill cleanup.
                Under certain situations, the USCG National Strike Force would be called to provide assistance to the OSC.
                The Gulf Area Strike Team, located in Mobile, Alabama, is part of the National Strike Team and is equipped
                with specialized containment and removal equipment with rapid deployment capabilities.
                    In compliance with the revisions made through the Oil Pollution Act of 1990 to the Federal Water
                Pollution Control Act, the USCG has recently, August 1991, established a National Response Unit in Elizabeth,
                North Carolina, and USCG District Response Groups throughout the U.S.
                    Although the recently created (commissioned September 1991) NSFCC located in Elizabeth City, North
                Carolina, will not warehouse equipment, it will be available to administer the three USCG Strike Teams, to
                conduct training exercises, to serve as a public information assist team, and to keep a computerized national
                and international inventory of spill-response equipment The NSFCC will be fully manned and operational by
                Summer 1992.
                    The USCG is also charged with the responsibility (under OPA) to create USCG District Response Groups
                to provide quick first aid to a spill. The groups are not intended to be the primary cleanup resource; they are
                only intended to provide a rapid spill-response capability and assistance to the primary cleanup contractor.
                One of the primary assets available to the USCG District Response Groups will be pollution control and
                cleanup equipment, which will be prestaged at 19 locations throughout the country. These locations and the
                selection of the equipment were based on several USCG studies that considered known and proposed
                stockpiles of industry provided response equipment and the risk of a spill occurring in specific geographical
                areas. Sites selected in the Gulf Coastal States include Corpus Christi and Galveston, Texas; New Orleans,
                Louisiana; and Tampa, Miami, and Mayport, Florida. Equipment for each of the 19 sites (at a cost of
                approximately $1 million to equip each site) includes containment boom (2,000 ft of harbor and 2,500 ft of
                open ocean boom), two vessel of opportunity skimming systems (VOSS's), and two portable collapsible barges
                to hold collected oil.
                    The VOSS's are designed to be used on vessels over 65 ft in length that would be available in the area.
                It is expected that offshore supply vessels or fishing vessels may be used. The equipment will be stored on flat
                beds for quick transport; however, a truck would need to be hired to transport the equipment in the event of
                a spill. The 2,000 ft of harbor boom will be packaged to be easily transported by helicopter. The Gulf Area
                Strike Team is expected to receive additional equipment similar to that being purchased for these 19 sites.
                    Approximately 49 Marine Safety Offices nationwide, which are not located in proximity to one of the 19
                staging sites, will receive equipment to enhance their response capability. Equipment placed at these sites will
                include a small skimmer system, 1,000-2,000 ft of harbor boom, a mooring system, and a trailer. All of the
                USCG equipment is expected to be in place by Fall 1992 at the latest. The USCG is also looking at putting
                skimming operations on offshore and coastal buoy tenders as they come off-line.
                    Equipment purchased by the MSRC is discussed in Section IV.C.61 Recent equipment acquisitions and
                future procurement plans to increase CGA!s equipment inventory are discussed in Section IV.C.6.d.











                  IV-138

                  (2) EquipmentlResponse Options and Effectiveness

                  (a) Mechanical Equipment

                      A wide variety of mechanical equipment is available to aid in the containment and cleanup of spilled oil.
                  Some general categories of oil spill cleanup and containment devices include booms, skimmers, pumps, and
                  sorbents.
                      Oil-spill control booms are floating barriers designed to contain spilled oil for recoveiy, to divert oil to
                  areas where recovery is more easily carried out, and to act as a barrier in pathways to areas containing
                  commercially valuable or environmentally sensitive resources. Boom designs vary considerably, but all of them
                  usually incorporate the following features: freeboard to prevent or reduce splashover; subsurface skirt to
                  prevent or reduce the escape of oil under the boom; flotation by air or some buoyant material; and a
                  longitudinal tension member (chain or wire) to withstand the effects of winds, waves, and currents. The length
                  and size of boom sections are important considerations. The optimum size of a boom is largely related to the
                  sea state under which it is to be used. As a general rule, the minimum height of freeboard to prevent oil
                  splashover should be selected; and the depth of the skirt should be of similar dimensions. Short section lengths
                  of boom are easier to handle and can protect the integrity of the boom as a whole, should one section fail;
                  however, this should be weighed against the difficulty of connecting the sections effectively. A, boom is typically
                  constructedof modern lightweight/high-impact materials (high strength-to-weight ratio) and packaged compactly
                  to allow for case in transportation and deployment Booms generally cannot contain oil against water velocities
                  much in excess of 1 knot (kn) (0.5 m/s) acting at right angles to it. The escape velocity for most booms is
                  around 0.7 kn (0.35 m/s), irrespective of skirt depth (Oil Spill Intelligence Report, 1984a).
                      Skimmers are mechanical devices designed to collect spilled oil from the water surface for disposal without
                  chemically or physically altering the oil. Skimmers are classified on the basis of their operating principles into
                  the following major groups: weir skimmers (provide gravity drain off to oil); vacuum skimmers (similar to weir,
                  but use a power source to actively remove the oil); centrifugal skimmers (where a power source is used to
                  create a vortex that drains the oil for collection); submersion skimmers (force the oil below the water level and
                  use its buoyant property in the collection process); and oleophilic skimmers (collect oil on a moving sorbent
                  material and mechanically squeeze it into collection areas) (Oil Spill Intelligence Report, 1,984b).
                      Each of these skimmer types has its advantages and disadvantages, although the efficiency of each model
                  depends on several parameters, including oil thickness, oil viscosity, sea state, and storage capability. Each type
                  of skimmer is best suited for a particular situation; no skimmer is effective in all conditions. In addition, since
                  the skimmer is part of a system involving the containment and recovery of the spilled oil, as well as the
                  separation of the oil/water mixture and the transportation of that mixture to receptacles, the overall efficiency
                  of a skimmer depends on the effectiveness of the individual components of the system (Oil Spill Intelligence
                  Report, 1984b).
                      Pumps are used in oil spill cleanup operations to transfer collected oil from a collecting. device, such as a
                  boom, to a vessel or facility for separation, reprocessing, storage, or transportation to other facilities. Although
                  specifications of the various pumps available are not relevant to this discussion, it should be recognized that
                  pumps are necessary for cleanup operations.
                      Sorbents are those materials that recover oil by either absorption or adsorption. In absorption, oil
                  p@netrates the solid structure of the adsorbents' fibers or particles, which then swell in size to accommodate
                  the oil. In adsorption, oil adheres to the surface of the adsorbent material but does not penetrate the fibers
                  or particles themselves. Sorbent materials are generally classified by their composition: (1) natural organic
                  products, such as hay, peat moss, straw, or wood pulp; (2) mineral compounds, such as ash, perlite, or
                  vermiculite; and (3) synthetic products, such as polyethylene, polypropylene, or polystyrene. Sorbents are
                  usually marketed in particulate form or as booms, pillows, rolls, or sheets. Synthetic products are generally
                  preferred over natural sorbents because they are able to absorb more oil while taking on less water. For this











                                                                                                                           IV-139

                 reason, they take up less storage space and pose less of a disposal problem (Oil Spill Intelligence Report,
                 1984c).
                     As previously stated, winds and sea state have a significant effect on the performance of the
                 aforementioned oil spill equipment In general, 15-20 kn are the maximum wind speeds for dynamic upwind
                 recovery, and recovery over sea states of 3-4 ft is essentially undocumented (Tennyson, personal comm., 1988).
                 Of additional importance is the period of the waves. When an increase in winds produces short-period,
                 localized seas, the efficiency of oil spill containment/cleanup devices decreases because the equipment tends
                 to get swamped in the wash of these choppy waves. Large rolling waves (long period) present less problems
                 due to the ability of the equipment to follow the waves' contours (Oil Spill Intelligence Report, 1984b).
                     Initial response to an oil spill occurring due to OCS oil-development activities is available through
                 equipment owned by CGA. Open-ocean equipment available through CGA includes FRS and the HOSS
                 barge. The FRS is essentially a vessel of opportunity skimming system (VOSS) in that it is designed to be
                 loaded onto a single vessel supplied by the lessee. Vessel length can range from 65 to 100 ft. Fast Response
                 Systems are staged at onshore locations throughout the Gulf as indicated by Table IV-23. Once an IRS unit
                 is loaded onto a vessel, the vessel is generally capable of a 10- to 15-kn response dependent upon the size of
                 the vessel utilized. Clean Gulf Associates' FRS consists of a barrier (two sections of 24-ft lengths of 48-in
                 boom) connected to a weir skimmer and towed alongside a single vessel with an outrigger, an oil-water
                 separator system, and recovered oil-storage capacity.
                     Due to the problems of equipment and manpower coordination inherent in an oil-spill response, skimming
                 systems deployed from single, independent vessels are an attractive means of recovering spilled oil offshore.
                 Whereas a large sweep system is advantageous on large, unified slicks, a VOSS can be deployed more quickly,
                 is more maneuverable (for skimming windrows of oil, for example), and requires only one vessel (Crocker,
                 1985). Operations of single-vessel systems are presently limited by the deployment and retrieval of the
                 skimming system in rough conditions rather than by barrier performance in waves (Crocker, 1985). The CGA
                 reports that the FRS weir skimmer will pick up essentially all the slick presented to it at boat speeds of 3/4 to
                 11/4 kn in seas up to 2 ft As seas pick up and/or boat speed increases, however, effectiveness of the system
                 decreases. This system has been tested at the Oil and Hazardous Materials Simulated Environmental Test
                 Tank (OHMSETT) under varying conditions with both heavy and medium oils. The tests showed that
                 throughput efficiencies ran as high as 100 percent for speeds of 1.25 kn, with an oil recovery rate of 293 bbl
                 of oil per hour in a slick that was 2 mm (0.08 in) thick. The skimmer was tested under severe harbor-chop
                 conditions of 2 ft, resulting in throughput efficiencies of 70 percent (USDOI, MMS, 1987a).
                     The HOSS barge located in Grand Isle, Louisiana, consists of a skimming system built into a specially
                 designed 174-ft barge. Boom (1,000 ft total) is stored on two sides of the barge and is launched off the stern
                 by means of a trolley running down ramps cut into the hull. Mounted in slots in the barge's stern are four
                 oleophilic belt skimmers, each followed by a weir skimmer. The HOSS barge is designed to be utilized to skim
                 extensive long-duration spills where chasing after slicks is not required and to provide offshore operational
                 support for spill recovery. This system must be towed to an oil spill site. Tow speed is typically 4-7 kn. The
                 HOSS barge is capable of working in up to 6-ft waves with boom and 7-ft waves without boom.
                     The main objective in any offshore spill response effort is to prevent the oil from damaging resources by
                 containment and recovery of the spill. The CGA currently has 500 ft of 72-in offshore boom stockpiled at
                 Grand Isle, Louisiana, primarily as a replacement boom to the HOSS barge. The CGA has finalized the
                 procurement of 18,000 ft of open-ocean boom that has been strategically sited along the Gulf Coast at existing
                 CGA bases. Approximately 1,500-3,000 ft of the boom are stockpiled at each of the CGA bases. The boom
                 chosen can be easily stored, deployed, and retrieved. The CGA is in the process of finaUing the procurement
                 of 10,000 ft of tricompartment shoreline boom that will also be strategically sited along the Gulf Coast. The
                 shoreline boom will be used to isolate an oiled section of the beach from a clean or biologically sensitive area
                 to protect the adjacent areas from being oiled. Other offshore booms, which may currently be available
                 through Gulf of Mexico oil and gas operators, would include the 750 ft of boom that is required to be located
                 at each rig site or staging area in the Florida panhandle during drilling activity in those areas located in the
                 EPA- Booms procured by CGA for open-ocean use are generally capable of being deployed in less than 1











                  IV-140

                  hour and can generally operate effectively in waves up to 6 ft. Lengths of 36-in nearshore containment booms,
                  self-propelled skimming vessels, hand skimming systems, floating suction oil skimmers for use in shallow water,
                  and sorbents make up a portion of the remaining inventory available through CGA.
                      Clean Gulf Associates has also initiated the establishment of four identified vessels to bestrategically sited
                  at various locations offshore and equipped to provide an initial response effort in the event of an oil spill.
                  These boats are strategically located in areas having a high concentration of off production. The first three
                  identified vessels are currently staged offshore and will be available to the general CGA raembership once
                  contractual problems are resolved. Establishing the identified vessels required procurement of additional
                  equipment, such as skimmers, to outfit the vessels. A skimming system, including a crane, power pack,
                  outrigger and boom, skimmer (designating 200 gpm) and a 2,100-gallon oil separator, are skid mounted on each
                  vessel. Five hundred feet of open-ocean boom, which is to be used for containment in conjunction with
                  skimming operations, is also stored on the vessel. Approximately W,000 was approved by CGA to outfit the
                  first identified vessel, which is located offshore at South Timbalier Area Block 26. The other vessels are
                  located in West Cameron Area, Block 71 and in South Marsh Island, Block 239. The fourth identified vessel
                  is expected to be in place by mid-1992.
                      In the event of a spill by a member CGA company, the member would call the Halliburlon dispatcher for
                  release of the ID boat. Upon approval by a member of the CGA Executive Committee or the Executive
                  Director, the operator contracting the vessel (Shell, Mobil, or Texaco) would release it to respond to the spill.
                  The identified vessel would be the first responder to the incident and would remain on scene until the backup
                  equipment reaches the scene from the CGA shore base locations. At this time the identified vessel would be
                  returned to service for the operator.
                      Another planned addition to the CGA stockpile are two additional shallow-water sldmmers. These
                  skimmers were selected because of their durability, storage capacity, shallow draft, unmanned operation
                  potential, and ability to handle weathered oil.

                  (b) ChemicalslDispersants Usage

                      Chemical dispersants may potentially be used as an off-spill mitigation tool. Tables IV-23 and IV-24
                  delineate the major locations presently stockpiling dispersants in the Gulf of Mexico. The key components of
                  chemical dispersants are surface-active agents (surfactants), which are molecules that have both water-soluble
                  (hydrophilic) and oil-soluble (hydrophobic) ends. These molecules, when applied to art oil spill, orient
                  themselves at 'the oillwater interface such that the hydrophilic ends of the molecules are in the water and the
                  hydrophobicends are in the off. The result is a reduction of interfacial tension between the oil and water. This
                  action reduces the cohesiveness of the oil slick and, with agitation, finely dispersed oil droplets (ranging in size,
                  depending on the effectiveness of the surfactant formulation, from about 10 microns to 0.5 mm in diameter)
                  are formed in the near-surface water. The hydrophilic surfactant groups prevent droplet recoalescence.
                      Dispersant formulations have changed since the Torrey Canyon spill in attempts to develop more effective
                  and less toxic products. These so-called second-generafion dispersants, introduced in the late 1970's, are being
                  manufactured today. Therefore, only the current (late 197.0     9s to the present) literature on effects of dispersed
                  oil is relevant. Some studies have investigated the toxicity of dispersants alone (Wells, 1984). Studies that have
                  considered species indigenous to the Gulf of Mexico, such as mangroves, seagrasses, and corals, include those
                  by Baca and Getter (1984), Getter and Baca (1984), Getter and Ballou (1985), Teas et al. (1986), and
                  Thorhaug et al. (1986).
                      The LOOP, Inc. has completed static and flow through toxicity tests on five Gulf species-.-brown and white
                  shrimp, blue crab, eastern oyster, and red fish--in August 1988. The test results showed that when the test
                  species were exposed to chemically dispersed Mayan or Saudi Arabian light crude oil, the observed toxicity
                  occurred rapidly, usually within 6 hours after addition of the dispersed oil. The test animals that survived the
                  first 6-12 hours of exposure usually recovered and survived for the remainder of the test period. In almost all
                  cases, surviving test organisms were swimming normally and were not lethargic 12-24 hours after test material
                  addition. Test results indicated that if the organisms were exposed to dispersed Mayan or Saudi Arabian light












                                                                                                                            IV-141


               crude oil but survived long enough for the material to decrease in concentration, the organisms could recover
               and survive without any apparent short-term effects (Shuba and Heikamp, 1989). Also, MMS has recently
               awarded Continental Shelf Associates a contract to conduct an Oil and Oil Dispersant Toxicity Study. The
               objective of this study is to collect additional data on the toxicity of dispersed oil to selected Gulf species,
               particularly the eggs and larvae of a few important commerical and recreational fisheries species of the north-
               central Gulf.
                    The decision to use dispersants must be made soon after the spin occurs. Weathering of oil will increase
               the viscosity and decrease the capability of chemically dispersing the oil. Factors to be considered in making
               this decision are oil type and properties, environmental conditions, the availability of dispersant and application
               equipment, and the probable fate of the oil without treatment. Highly viscous oils (greater than 5,000
               centistokes), oils with pour points near or above ambient temperature, and oils with a high wax or asphaltene
               content may notbe amenable to dispersant treatment (International Tanker Owners Pollution Federation, Ltd.,
               1982; Canevari, 1985). Dispersants are not recommended for use on spills on very calm waters. Some
               dispersants are formulated for use on marine (saltwater) spills only.
                    Dispersants may be applied by boat or aircraft. Boat application is limited to small spills or those within
               a few miles of shore. Aerial spraying is the preferred method because it offers rapid response, coverage of
               large areas per unit of time, good control of treatment rates, optimum use of dispersants, and much better
               evaluation of treatment results than is possible from boats. Regardless of the method used, the application
               system must deliver the proper dosage of dispersant in a uniform spray of droplets to the slick. Most oil slicks
               considered for dispersion will be 025 mm thick or less (a 0.25 mm thick slick contains over 4,000 bbI per
               square mile of oil). The dispersant must penetrate the oil to reach the oil/water interface. The proper dosage
               of dispersant (5 gal/acre is an average amount, depending on the dispersant and the oil types) must be used
               to attain the maximum reduction of interfacial tension. Finally, some form of energy (e.g., wind, wave, or
               mechanical) must be applied to the oil/water interface to cause the dispersion of oil into the upper part of the
               water column. Newer types of dispersants require very little mixing energy.
                    The National Oil and Hazardous Substances Pollution Contingency Plan (NCP) requires that the USCG
               on-scene coordinator obtain the concurrence of the USEPA representative to the Regional Response Team
               (RRT) and, as appropriate, the concurrence of the RRT representatives from the states having jurisdiction over
               the navigable waters threatened by the release or discharge, and, when practicable, consult with the DOC and
               DOI natural resource trustees prior to authorizing the use of a chemical agent. Approved chemical agents
               must be listed on the NCP Product Schedule. The OSC is not required to obtain the aforementioned
               concurrence when, in the judgement of the OSC, the use of a chemical agent is necessary to prevent or
               substantially reduce a hazard to human life. Consistent with this, a Memorandum of Understanding between
               the Department of the Interior and the Department of Transportation dated August 16, 1971, allows MMS the
               authority to grant approval to OCS operators to use chemical agents within a 500-m radius of the source of
               pollution only when such agents are deemed necessary to abate the source of pollution as a measure for the
               safety of personnel and operations.
                    Dispersant use in the Gulf of Mexico is controversial and has not yet been fully accepted by the five Gulf
               States, which, along with USEPA, have approval authority regarding the use of dispersants in waters off their
               shores. The States, however, by their participation in the Regional Response Teams (RRT's) and the
               Dispersant Working Groups (DWG's), are reviewing relevant data with an eye to approving dispersant use
               under certain specific conditions. Recent Federal and State progress has been made in this area. Recent
               progress made towards the designation of areas in the Gulf for which dispersant use may be preapproved has
               been encouraging. The Louisiana Offshore Oil Port recently developed a plan that requests preapproval of
               the use of dispersants within a designated area near the LOOP facility. In acknowledgment that an effective
               dispersant response is an immediate one, the USEPA Region VI Regional Response Team granted pre-spill
               authorization for the use of dispersants within a designated geographic area surrounding the LOOP facility to
               the Federal OSC in 1991.











                  IV-142

                      The National Research Council (NRC) of the National Academy of Sciences has addre:;sed the effects of
                  dispersants in its review, "Using Oil Dispersants on the Sea." The study addressed two questions about the use
                  of dispersants: (1) Do they do any good? and (2) do they do any harm? (NRC, 1989).

                           Do they do any good? This is not an easy question to answer. In a few carefully planned,
                           monitored, and documented field tests, as well as in laboratory tests, several dispersants have
                           been shown to be effective --- that is, they have removed a major part of the oil from the water
                           surface when properly applied to oils that were dispersible. However, at other field tests and
                           at accidental spills, dispersants have been reported to have low effectiveness. The latter
                           results may have been due to the use of inadequate application techniques, such as poor
                           targeting and distribution of aerial sprays, as well as the possibilities that the oils were not
                           dispersible, that some dispersants were poorly formulated, or that the results were
                           inconclusive. Resolution of these ambiguities will require further studies. Much is known of
                           how dispersants work, but one aspect inadequately understood is the interaction of various
                           physical and chemical processes involved in oil dispersion.

                           Do they do any harm? Concern that chemical dispersants could be toxic to marine life has led
                           to considerable caution in authorizing their use at spill sites. Laboratory studies of dispersants
                           currently in use have shown that their acute lethal toxicities are usually lower than crude oils
                           and their refined products. A wide range of sublethal effects of dispersed oil has been
                           observed in the laboratory. These occur in most cases at concentrations comparable to or
                           higher than those expected in the water column during treatment (I to 10 ppm), but seldom
                           at concentrations less than those found several hours after treatment of a oil slick I'less than
                           1 ppm). The times of exposure in the laboratory (24 to 96 hours) are much longer than
                           predicted exposures during slick dispersal in the open sea (1 to 3 hours), and the effects would
                           be expected to be correspondingly less in the field. Laboratory bioassays have shown that
                           acute toxicity of dispersed oil generally does not reside in the dispersant, but in the more toxic
                           fractions of the oil. Dispersed and untreated oil show the same acute toxicity. The immediate
                           ecological impact of dispersed oil varies. In open waters, organisms on the surface will be less
                           affected by dispersed oil than by an oil slick, but organisms in the water column, particularly
                           in the upper layers, will experience greater exposure to oil components if the oil is dispersed.
                           In shallow habitats with poor water circulation, benthic organisms will be more immediately
                           affected by dispersed oil. Although some immediate biological effects of dispersed oil may
                           be greater than for untreated off, long-term effects on most habitats, such as mangroves, are
                           less, and the habitat recovers faster if the oil is dispersed before it reaches that area.

                      The report went on to make several recommendations regarding future studies; it also recommended that
                  dispersants be considered as a potential, first-response option to oil spills, along with other response options.
                      An oil-treating agent called "Elastol," which is not a dispersant, aids in the containment and recovery
                  aspects of oil-spill. cleanup. Elastol is a nontoxic powder that dissolves rapidly when dispensed on hydrocarbon
                  liquids. It modifies the oil, giving it a viscoelastic property and making recovery more efficient, and is usable
                  on light and heavy crude oils, kerosene, diesel, gasoline, bunker, and many other hydrocarbons. In recent tests,
                  the application of Elastol on offshore oil spills in 500-900-ppm quantities increased the performance of
                  skimming equipment 2-5 times over untreated performance recovery rates. It also minimized oil spreading,
                  streaking, and breakup due to wind and wave conditions of up to 15 kn. When used with booms, it shows
                  successful containment in currents over 1 knot. It should be noted, however, that the effectiveness of Elastol
                  has not yet been proven under field conditions; and, like dispersants, its usefulness is still the subject of some
                  controversy. Additional information on Elastol can be obtained from a technical paper entitled Laboratory
                  and Tank Test Evaluation of Elastol, which was presented at the "Tenth Arctic and Marine Oil Spill Program
                  Technical Seminar" (Bobra et al., 1987).











                                                                                                                            IV-143

                 (3) Response Times

                     Although regional oil spill contingency plans submitted for the Gulf of Mexico do not specify response
                 times, the supplemental oil-spill information submitted for EP's and DOCD's does provide a response time for
                 operations on a particular lease. Review procedures for an operator's response time submitted as supplemental
                 information to a EP or DOCD are discussed in Section IV.C.6.b.
                     The USCG has established guidelines for response times for OCS operations in Commandant Instruction
                 5740.6. The instructions request a target response time of 6-12 hours from the time of the spill, dependent on
                 the location and general operating characteristics of the OCS operations. However, this 6- to 12-hour range
                 for response times is not flexible enough to cover the wide variation in the distance of the leased areas in the
                 Gulf of Mexico to the shoreline or to the nine CGA-designated spill-equipment bases.
                     Initial response times in the Gulf of Mexico to an oil spill would vary dependent upon the chosen
                 spill-equipment base, the distance of the block to the chosen spill-equipment base, the travel speed of the
                 chosen vessel, the amount of time needed to procure and deliver a vessel to the spill-equipment staging area,
                 the time needed to transport the oil-spill response crew to the spill-equipment loading base, the load-up time,
                 and the deployment time. The utilization of some staging areas would require a longer period of inland water
                 travel at reduced speeds, which could significantly increase a response time. Additionally, although most OCS
                 operators are members of CGA, the few that are not may incur delays at the time of a spill while negotiating
                 an agreement with the co-op for the use of the equipment However, the establishment of identified vessels
                 at strategic offshore locations by CGA should alleviate many of these variables affecting response times and
                 consequently should effectively reduce initial response times to some areas of the Gulf.
                     Until the finalization of the identified vessel concept throughout the Gulf Region, first response to an oil-
                 and gas-drilling-related spill in the Gulf of Mexico would generally be made utilizing CGA equipment staged
                 at onshore locations. Each operator would be responsible for supplying their own vessels, cranes, and
                 personnel when utilizing CGA equipment. The majority of the facilities located more than 97 kin (60 mi) from
                 an onshore equipment base currently have response times greater than 12 hours. These response times are
                 based on an estimate of 4 hours for the procurement and mobilization of both personnel and a vessel to a
                 subject base, an estimate of 2 hours to load the equipment onto the support vessel, an estimate that the
                 procured vessel would travel at 10 mph in open water, and an estimated channel run time. An internal study
                 of the projected response times submitted to date by Gulf of Mexico OCS operators was made to determine
                 these estimates. Some variance of these estimated times can be expected depending upon the availability of
                 a vessel and the distance of the spill response personnel headquarters from the subject CGA base location, as
                 well as the wind and weather conditions at the time of a spill. It should be noted, however, than an oil spill
                 at these distances from shore would not normally be an immediate threat to coastlines in the Gulf because (a)
                 prevailing currents and winds do not tend to move spills directly toward shorelines, (b) the greater the distance
                 from shore of a facility, the greater the time available before a coastline could be impacted, and (c) Gulf crude
                 oils are generally light and, therefore, easily and naturally dispersed.
                     The establishment and offshore staging of CGA!s identified vessels provide the first stage of a tiered
                 response. The equipped, identified vessels are sufficient to handle smaller size spills and to provide initial
                 response to larger spills until back up equipment could reach the spill site. Back-up equipment is available
                 through CGA bases located throughout the Gulf Coast, the USCG Atlantic Area Strike Team base in Mobile,
                 Alabama, and from numerous contractors and oil companies in the Gulf Coast area.
                     A large number of operators in the Gulf of Mexico presently propose the use of contract personnel to load
                 and operate the CGA equipment. These operators typically enter into a "no fee" type of contract with one or
                 more of these companies to provide spill response on a 24-hour basis if they are available at the time of a spill.
                 Because these companies are not located in close proximity to all of CGA!s spill-equipment bases, the delivery
                 of the contract personnel to a spill base for loadout could increase a projected response time. Trained oil-spill
                 response personnel can generally be transported from locations throughout the Gulf Coast to CGA!s nine base
                 locations by helicopter in time periods ranging from 40 minutes to 2 1/2 hours. This timeframe may be longer
                 depending upon the weather conditions at the time of a spill, as it could require up to 6 hours to drive contract
                 personnel to some of the bases.










                  IV-144

                      Vessel procurement has been identified by numerous OCS operators as one of the biggest limiting factors
                  in attempting to reduce response times in the Gulf of Mexico. Vessel procurement times over 12 hours have
                  been projected in some instances. Many operators request using a spill-equipment base nearer their onshore
                  support base rather than a base closer to the subject lease to ensure that a vessel could be procured within a
                  reasonable time. Most companies prefer to rely upon vessels they have already contracted with as opposed
                  to attempting to contract or borrow a vessel from another company at the time of a spill. Other problems
                  encountered regarding vessel procurement are the availability of large vessels (160-180 ft in Itength) that would
                  be needed to respond to deep-water blocks and the limited number of spill-equipment base locations that could
                  handle these large vessels. These factors could significantly increase an already lengthy response time to a
                  deep-water area.
                      Hopefully, CGA!s effort to locate four identified and equipped vessels at strategic offshare sites in the Gulf
                  of Mexico will be a start in successfully alleviating many of the vessel procurement problerns identified in the
                  Gulf.

                  (4) Offshore CZeanup Capabi1hy for Ran&iAg Various Size Spi&

                      The MMS-required OSCP's describe response actions for two types of spills--continuous spills and spills
                  of short duration and limited maximum volume. Response to a very large spill, if the spill results from an
                  instantaneous release, is not described; however, the discussion of response actions to continuous spills included
                  in MMS required OSCP's would be equivalent to a "very large spill" that may result from off and gas drilling
                  or production activity. If the spill were very large, in addition to company-owned and CGA equipment, industry
                  would attempt to access available uncommitted equipment (generally that equipment available regionally that
                  is not part of CGA!s stockpile) that could help in containing the spilled off as identified in their OSCP's.
                  Logistics for transporting and deploying this uncommitted equipment would, however, have to be worked out
                  at the time of a spill. The OPA requires that offshore facility plans identify and ensure by contract the
                  availability of private personnel and equipment necessary to remove, to the maximum extent practicable, a
                  worst case discharge.
                      An examination of the daily cleanup capacity of CGXs major cleanup equipment described above can be
                  used to estimate the amount of oil that industry could remove from the slick daily. The FTtS and the HOSS
                  barge serve the industry in cleaning up spilled oil in open seas. The HOSS barge would only be used for spills
                  of long duration, such as blowouts, because of the amount of time to transport the barge to the spill site. This
                  system can recover a nominal amount of 4,300 bbl of fluid per day. The oil tanks can hold about 4,100 bbl
                  and can be offloaded to other oil storage barges. The FRS's would be used for spills of short duration and to
                  supplement the HOSS barge. The recovery pumping system of the IRS is conservatively estimated to handle
                  1,000 bbl per 12-hour day (Union Exploration Partners, Ltd., 1988). As previously stated, during OHMSETT
                  testing under varying conditions with both heavy and medium oils, throughput efficiencies for the FRS ran as
                  high as 100 percent for speeds of 1 1/4 kn, with an oil recovery rate of 293 bbl of oil per hour in a slick 2 min
                  (0.08 in) thick (USDOI, MMS, 1987a). Clean Gulf Associates currently has 13 IRS units, which could be
                  utilized during a spill staged at locations throughout the Gulf of Mexico. Obviously, the response capability
                  in the Gulf of Mexico would vary depending upon the number of FRS units deployed to the spill site. In the
                  event of a 10,000-bbl oil spill, one medium-size skimmer capable of picking up 600 bbl of fluid/hr, which would
                  have similar capacity to one FRS, would be required for a maximum of 7 days working 12 hours/day to recover
                  the total fluid to be recovered (50,000 bbl--20% oil/80% water). A 63,000-bbi oil spill would require six
                  medium-size skimmers to recover the total fluid necessary (315,000 bbl of fluid) over the same timeframe
                  (Exxon, 1979). The recovered oil-storage capacity of an IRS is 100-180 bbl. Recovered oil in excess of the
                  100- to 180-bbl FRS storage capacity could be temporarily offloaded to the supply-vessel tanks. However, a
                  waiver from the USCG would have to be obtained to utilize the mud tanks in the supply vessel for auxiliary
                  recovered oil storage. Other options for additional recovered oil storage would include the 50-bbl. oil storage
                  barges available through CGA or oil barges located throughout the Gulf of Mexico. Contacts for the
                  procurement of these oil barges are provided in the Gulf of Mexico lessees' OSCP's.











                                                                                                                             IV-145

                   It should be noted that offshore cleanup operations to open-water spills have, for the most part, been
              ineffective, as evident in the Alaskan oil-spill response efforts. Despite the massive effort to clean up the oil
              in Alaska, cleanup crews were able to recover no more than 15 percent of the spilled oil. According to the
              U.S. Congressional Office of Technology Assessment (OTA) report entitled Coping With An Oiled Sea: A
              Background Paper some experts feel that the most oil that can be recovered after a major spill is 10-15 percent.
              Information obtained by OTA from several documented open ocean tanker spills show that the actual oil
              recovered at sea has usually been much less than 10 percent of the oil discharged (Johnson et al., 1990).
                   Mechanical containment and recovery remains the primary spill response method utilized in the U.S. The
              current technology available for mechanical oil spill cleanup has many limitations. The OTA report indicates
              that while new designs have appeared over the years, the basic technology has not changed much over the past
              decade. The report also indicates that while improvements in mechanical recovery technologies can be
              expected from stepped-up research and development efforts, they are unlikely to result in dramatic increases
              in the amount of oil that can be recovered from a catastrophic spill. In general, the OTA report stated that
              the improvements made in mechanical off spill clean up technology that would be more likely to offer greater
              effectiveness for large offshore spills would involve larger, more costly equipment, strategically located for a
              quick response (Johnson et al., 1990).

              (5) Coastal Ckanup Techniques and Effects

                   Whenever possible, spill response should be carried out on water, as most equipment and techniques have
              been designed for such an approach. However, when a spill contacts a coastline, several techniques can be
              used. The selection of the type of treatment onshore will depend on the type and the amount of oil on the
              shore, the nature of the coast, the depth of oil penetration into the sediments, the accessibility and trafficability
              of the shoreline, and the possible ecological damage of the treatment to the shoreline environment
              (CONCAVVE, 1981). The most suitable types of cleanup techniques to be used on a specific shoreline are
              shown on Tables IV-25 and IV-26.
                   Direct-Suction: If a beach, rocky area, or marsh has been contaminated with large volumes of oil and if
              the oil has pooled naturally in low spots or poorly drained areas, the use of direct suction can be a viable
              cleanup method. However, the effectiveness of this technique requires thick accumulations of oil. Direct
              suction can be accomplished with a pump, hoses, and a storage container. Recovered oil can be stored in
              metal storage containers, natural depressions lined with an impervious material, or a truck used for storing
              liquids. Another option is to use a vacuum truck equipped with a pump. Direct suction also can be applied
              to spills that have saturated porous soil types, such as sand and silt, by mechanically cutting a trench to act as
              a collection area for the oil (USDOI, MMS, 1987a).
                   Manual Removal: Where oil contamination is low or sporadic, or when penetration of the oil into the
              sediment is low, manual removal of the oil is preferred. Manual removal usually is used to some extent on any
              shoreline cleanup, in combination with other techniques or alone. Due to logistical constraints or to access
              constraints placed on heavy equipment in some areas, manual recovery may be the only cleanup technique
              possible for some shoreline spills. This type of response is very time-consuming, costly, and labor-intensive;
              however, it might be the only way to deal with a spill. Manual removal is a very selective method of removing
              contaminated sediment and vegetation, making it an extremely effective response technique. The effectiveness
              of a manual response is directly related to the amount of time, labor, and money the operator wants to devote
              to the problem. The more money and time invested in a manual cleanup operation, the greater the amount
              of oil that may be recovered (USDOI, MMS, 1987a).
                   Manual recovery involves the use of hand tools--such as rakes, shovels, buckets, pickaxes, brush cutters,
              scythes, and power brush-cutting tools--to remove contaminated sediment and vegetation. Oil-contaminated
              sediment or vegetation is collected and put into heavy-duty plastic or burlap bags for disposal. Bags may be
              removed manually, by vehicle, by boat or barges, or airlifted by helicopters to the disposal site (USDOI, MMS,
              1987a).


















                                                                        ILI,





                                                                                                                         0
                                                                  -F


                                                                                          ID
                                                                             of                                                                   (J 40       el                 01,
                                                                                                              10

                                    Method
                                                                                                                                     d,                              4?
                            Beach Cleaning Machines                                                             P      P
                            Boorrs/Skimmers                P      P                                V      P     A             P                         P            P     P
                            Burial                                             A                                A      A      A      A     A
                            Burning                        NA     NA                               NA     NA           A                   A            A     A      A     A-
                            Dispersonts                    P      V            NA     INA          V      INA   V      A      NA     P     A      V     NA    V      P     V
                            Earth Barriers                   I                                I      I            I      I            I            I      I
                            Herdina                        V      V                                                                                                  V     V
                            High Pressure   Flushing                           A          NA       INA    NA    A      A      A      NA    A      INA   V            NA    A
                            Low Pressure    Flushing                           V      V            V      V            V      P      P     V      R     P     V      P     P
                            Management (Drainage)                                                                                                                    P     P
                            Manual Removal                            V        INA    NA  NA       V      V     P      P      V      NA    P      INA                V     A
                            Natural Cleansinq                     P   P        P      P   PV       P      NA    P      V      p      P     NA     P           P      V     P
                            Sand Blasting                                                          A                                 NA           A
                            Sinking Agenis                 A      A
                            Sorbents                       V      V            NA     V   V        V      V     V      V      P      INA   V      V     V     NA     V     V
                            Stearn Cleaning                                                        A      A                          A            A                        A
                            Substrate Displacement                             A                                P      A      A      A            A
                            Substrate Removal                         NA       A                   A      A     P      INA    A      A     NA     A                  A     A
                            Vacuum Pumping                 V      V   NA       A      A   V        V            P      P      V            P            P     V      V     V
                            Vegetafion Cropping                                A      NA           NA     NA                                                               NA@

                            0 -   Pr t f - rr -- d
                            V     Viable
                            N A=  Noi Advisable
                            A =   Avoid
                                         Source: CSA, 1989.
                                                              @V






                    Table IV-25. Summary of Cleanup Methods.











                                                                                                Table IV-26

                                                                                        Shoreline Cleanup Methods

                          Method                                Description                                   Applicability                                           Effect


                High-pressure                          high-pressure stream of water               -  can be effective on rock,                        -  can damage flora and fauna
                Hoses                                  washes oil from the substrate                  boulder, and manmade surfaces                    -  can flush oil into sediments
                                                                                                   -  oil flushed onto water surface                   -  if beach is backed by
                                                                                                      for removal or channeled to                         unconsolidated cliffs, hosing
                                                                                                      beach collection site                               of cliff can cause slumps,
                                                                                                                                                          falls, or slope failure

                Steam or Hot-                          steam or hot-water washes oil               -  very effective on rock,                          -  can be very harmful to flora
                Water Cleaning                         from the substrate                             boulder, and manmade                                and fauna
                                                                                                      surfaces                                            can flush oil into sediments
                                                                                                   -  oil flushed onto water surface
                                                                                                      for collection or channeled
                                                                                                      to beach collection site
                                                                                                   -  expensive method
                Sandblasting                       - high-velocity sand removes                    -  effective but slow method for                       can be very harmful to flora
                                                       oil from the substrate                         rock, boulder, and manmade                          and fauna
                                                                                                      surfaces                                            scatters oil and sand
                                                                                                   -  can remove oil stains                               can cause deeper penetration
                                                                                                   -  expensive method                                    of oil into sediments
                Low-pressure Hoses                     low-pressure stream of water                -  effective but slow method for                       biologically preferable to
                                                       washes oil from the substrate                  rock, boulder, and manmade                          high-pressure hoses, steam
                                                                                                      surfaces                                            cleaning, or sandblasting
                                                                                                   -  oil flushed onto water surface                      can flush oil into sediments
                                                                                                      for collection or channeled to
                                                                                                      beach collection site

                Mixing                                 A - mechanical equipment such as            -  accelerates natural cleaning                        does not remove oil
                                                       rakes, discs, or harrows used               -  useful for light-grade oils or                      can cause burial of the oil
                                                       to break up oft cover and mix                  to break up "asphalt pavements"
                                                       surface sediments                           -  increases surface area of
                                                                                                      exposed oil and increases
                                                                                                      dispersal and degradation
                                                                                                      rates








                Table IV-26. Shoreline Cleanup Methods (continued)
                Mixing                              - B - mechanical equipment used to                -  accelerates natural cleaning                      -   does not remove oil                   4.
                                                        push oil/sediment down beach                  -  wave action disperses and                         -   should not be used if storm
                                                        into water                                       degrades oil                                          waves are expected before
                                                                                                      -  sediment is returned to the                           sediment is returned to the
                                                                                                         beach                                                 beach; could result in waves
                                                                                                      -  applicable for "asphalt                               overtopping the beach and/or
                                                                                                         pavements" or coarse-sediment                         causing backshore erosion
                                                                                                         beaches

                Removal

                Graders, Scrapers                   -   remove thin layer of oiled                    -  effective on sand or pebble                           removes sediment from the
                                                        sediments                                        beaches with low oil pene-                            beach, amount of sediment
                                                    -   graders form windrows for                        tration depths (less than 3 cm)                       removed usually not sufficient
                                                        scraper or front-end loader                   -  scraper can remove up to 25-cm                        to affect beach stability
                                                        to remove                                        layer of oil/sediment
                                                    -   scraper removes oil/sediment                  -  some spillage which can be
                                                        layer directly                                   removed manually

                Front-end Loaders                   -   loader removes material                       -  used on beaches with poor                             can result in excessive
                                                        directly from beach to                           traction or for high oil                              sediment removal that could
                                                        collection sites                                 penetration depths (25 cm or                          cause beach or backshore
                                                                                                         more)                                                 erosion
                                                                                                      -  high spillage                                         grinds oil into the beach
                                                                                                      -  usually large amounts of
                                                                                                         uncontaminated sediment are
                                                                                                         recovered
                                                                                                      -  rubber-tired vehicles are
                                                                                                         preferred to tracked vehicles

                Bulldozers                              push material into collection                 -  can remove oil/sediment where                         can result in excessive
                                                        sites for removal                                penetration is 25 cm or                               sediment removal that could
                                                                                                         greater                                               cause beach or backshore
                                                                                                      -  not recommended unless other                          erosion
                                                                                                         equipment unavailable or                          -   large spillage and grinds oil
                                                                                                         traction is too low for other                         into sediments
                                                                                                         equipment

                Dragline,                               sediment collected in bucket                  -  useful where beach access or                      -   can result in excessive
                Clamshell                               dragged towards equipment, or                    trafficability is poor                                sediment removal that could
                                                        by crane-operated bucket                                                                               cause beach or backshore
                                                                                                                                                               erosion








                  Table IV-26. Shoreline Cleanup Methods (continued)
                  Sump Collection                    -  sump excavated and used to                   -  useful for large spills with                     - does not remove all the oil
                  and Pump                              collect oil, which is then                      oil washed onshore over a                            from the beach
                  Removal                               removed by pump or vacuum                       period of days
                                                        systems

                  Manual                             -  A - oil scraped from the                     -  A/B - useful for areas inaccessible              -   A - selective oil removal, not
                                                        substrate                                       to equipment or small spills                         all oil is removed

                                                     -  B - oil collected with buckets,              -  A/B/C - labor-intensive methods;
                                                        shovels, rakes, forks, etc.                     slow rate of oil removal
                                                        (with or without sorbents)

                                                     .  C - cutting of oiled vegetation              -  C - oil/vegetation collected in                      C - labor-intensive method;
                                                                                                        containers for removal                               pedestrian traffic can disturb
                                                                                                                                                             marsh vegetation and can
                                                                                                                                                             cause oil/sediment mixing

                  in Situ Cleaning

                  Burning                            -  oil ignited, usually with                    -  seldom completely successful                         causes heavy air pollution
                                                        ignition agents                              -  useful for oil on surface of                         can increase the penetration
                                                     -  continued burning may require                   ice                                                  of oil into the sediments
                                                        wicking agents                               -  can be used in marshes with                          can damage root systems of
                                                                                                        appropriate biological advice                        marsh vegetation
                                                                                                     -  oil residues remain

                  Beach Cleaning                     - cleaner picks tar lumps from                  -  useful on beaches with tarballs                      little sediment removal
                  Machines                              the beach



                  Source: USDOL MMS, 1987b.











                 IV-150

                     Sorbents: Sorbent pads, booms, or rolls are often used as part of a manual response, or they can be used
                 in conjunction with other techniques. Small, isolated pools of oil on the sediments or on nearshore waters can
                 be removed by using sorbents. Once the sorbent materials have become soaked with oil, they can be removed
                 by the methods described above, or they can be burned (USDOI, MMS, 1987a).
                     Heavy Equipment: For certain areas, heavy equipment can be used as an effective cleanup technique. Its
                 use would require either the availability of roads or a means of air-lifting or barging the equipment to the
                 contaminated area. Only certain soil types, such as sand or rocks, could withstand heavy equipment. Graders,
                 scrapers, loaders, bulldozers, and backhoes are equipment that may be used in cleaning up shoreline areas.
                 This equipment can be used in areas where the soil-bearing capacity is adequate and habitats are not harmed
                 by removal of soils (USDOI, MMS, 1987a).

                     Flushing or Washing.

                         -   Low Pressure: For cleaning light oils, such as fuel oil, from lightly contaminated sediments
                             or vegetation, low-pressure flushing or washing can be a viable cleanup technique. In
                             performing this operation, water is pumped from the ocean and is flushed over the lightly
                             contaminated sediment to remove the off. The removed oil is trapped downstream in a
                             manmade trench or in a boomed-off area of the ocean close to shore. Once the oil is
                             trapped, it can be removed by direct suction, skimming, burning, or sorbent pads. This
                             technique is applicable only to shoreline areas because a nearby water source must be
                             available. Additionally, this technique is easier to carry out if the trench or boom can be
                             located downslope from where the flushing operations are being conducted.

                             Low-pressure flushing or washing operations are extremely labor intensive and may
                             damage the sediment by erosion or by driving the oil farther into the sediment. (USDOI,
                             MMS, 1987a).

                         -   High Pressure: High-pressure flushing is basically the same technique as low-pressure
                             flushing except that higher water pressures are used for high-pressure flushing. Typical
                             specifications for high-pressure flushing are a 10-gallon-(0.04-m) per-minute flow rate at
                             4,000 pounds per square inch (272 atm). The penetration of oil deeper into the sediment
                             with high-pressure flushing is an even greater danger than for low-pressure flushing
                             (USDOI, MMS, 1987a).

                     Steam Cleaning and Sandblasting: Steam cleaning and sandblasting are techniques that can be used to
                 remove off from rocks, boulders, and manmade structures. These techniques use high-pressure jets of steam
                 or sand to physically remove oil from the contaminated surface. Care must be taken in using these techniques
                 because the high-pressure streams can severely erode the sediment or damage any uncontaminated flora or
                 fauna in the area (USDOI, MMS, 1987a).
                     Natural Dispersion: Another option in dealing with shoreline cleanup that could prove very effective in
                 certain environments is natural dispersion.       For contaminated shorelines close to hig,     h-energy ocean
                 environments--such as sand, gravel, or cobble beaches--natural dispersion of the off into the ocean could be
                 very effective. Natural dispersion may be the only possible alternative when logistics or weather problems
                 preclude a response effort (USDOI, MMS, 1987a).

                 (6) In Situ Burning

                     In situ burning of spilled oil appears to have merit under certain spill conditions, especially if the oil can
                 be contained and thickened with fireproof booms. In order to ignite oil on water, the oil must be relatively
                 fresh and the slick must be at least three millimeters thick. Some oil residue ( about one millimeter thick layer)











                                                                                                                           IV-151

                will remain in the water after burning oil because the flame is always quenched by heat losses to the water
                surface when the off layer gets thin (Johnson et al., 1990).
                    Several techniques have been devised for igniting oil spills. Devices used include floating igniters that can
                be deployed by air and the helitorch igniter, which is a tank system containing gelled gasoline suspended on
                cables below a helicopter. One device under design is a laser ignition system using two coupled lasers from
                a helicopter to ignite oil spills (Johnson et al., 1990).
                    Although not currently an important off-spill countermeasure, this technique is currently being investigated
                further in the U.S. Some experiments have resulted in high burn percentages and thus high removal rates.
                Bum efficiencies of over 90 percent can be obtained, particularly if the oil is confined with booms or other
                means to keep the oil layer as thick as possible. Burning is, however limited in its applications. Igniting and
                keeping a slick burning may be a problem in some instances; in others, burning may jeopardize a vessel or
                facility; and the resultant visible air pollution may be unacceptable. This visible air pollution must, however,
                be weighed against the invisible air pollution caused by allowing evaporation of the toxic volatile compounds
                of an oil (Johnson et al., 1990).

                (7) Bioremediation

                    Bioremediation is the in situ use of microbes to biodegrade and oxidize hydrocarbon molecules.
                Biodegraders can be marine bacteria occurring naturally in the spill area, nonindigenous naturally occurring
                bacteria, genetically engineered microbes, and nutrients that can be added to enhance biological oxidation.
                Tests of this technique on water have shown little or no enhancement over the naturally occurring
                biodegradation. Use of bioremediation on impacted shorelines, however, has indicated effectiveness in some
                cases. Exxon, in conjunction with the USEPA, recently conducted a large-scale test of this technique in an
                attempt to clean up Alaska's oiled beaches as a result of the Exxon Valdez incident. Approximately 70 mi of
                shoreline were coated with two kinds of nitrogen- and phosphorous-bearing fertilizers to boost indigenous
                bacterial populations. Initial results are inconclusive, but the data are still being evaluated. One difficulty is
                measuring the effectiveness of the technique. The USEPA is also conducting separate bioremediation projects
                in this area. One such project will take place on Elrington Beach, a site that was heavily oiled last year.
                Researchers are particularly interested in determining the effects on subsurface oil and plan to use a sprinkler
                system to spray inorganic nitrogen, phosphorus, and seawater for three to four hours, once every four days
                (Johnson et al., 1990).
                    Bioremediation was also recently used during the clean up of the Mega Borg tanker spill that occurred in
                waters located offshore Texas. Permission was granted by the USEPA to conduct a controlled bioremediation
                experiment on a 100-M2 patch of oil. The experiment was modeled after a October 1989 test that was
                conducted in Port Aransas, Texas. The reportedly successful bioremediation results during the Mega Borg
                response have been met with a great deal of criticism from the oil spin community. Many bioremediation
                experts are skeptical about the use of the procedure on open-water spills, mainly because such an undertaking
                can be difficult to control and because of the long timeframe needed for effective use (Oil Spin Intelligence
                Report, 1991).
                    Proponents of bioremediation indicate that it is potentially the least costly of cleanup techniques,
                particularly for soiled beaches. Its use on water, however, would appear to be limited except as a follow up
                to other actions. The major disadvantage of bioremediation is the long timeframe needed for effective use.
                On beaches where it could take 5-7 years for off to break down under normal conditions, bioremediation with
                fertilizer could reduce that time to 2-5 years (Johnson et al., 1990).
                    A May 23, 1991 report, Bioremediation for Marine Oil Spills, released by the U.S. Congressional Office of
                Technology Assessment (OTA) stated that scientists are still evaluating the effectiveness of the use of
                bioremediation for marine oil spills (U.S. Congress OTA, 1991). The report concluded that recent research
                and field testing of bioremediation technologies on oiled beaches produced some encouraging if not altogether
                conclusive results. The report cited nutrient enhancement as the most promising use of bioremediation
                technology. The report also concluded that bioremediation has not proven to be an effective response to at
                sea oil spills.









                  IV-152

                  e. Response Options for Handling Oiled Wildlife and Birds

                      Rehabilitation of oil-contaminated wildlife may be necessary to protect species that are endangered or of
                  high aesthetic value. Successful programs are very labor intensive and have relied mostly ort volunteer labor.
                  Some of the studies that have been done regarding the effects of oil on marine mammals indicate that a few
                  mammal species may rid themselves of oil by washing. Animals that groom themselves may ingest oil, which
                  can result in mortality of the animal. Rehabilitation efforts may also stress certain animals, (musing increased
                  mortality and behavioral changes. Rehabilitation programs require extensive manpower to locate, capture,
                  treat, and care for oiled wildlife. The success of such a program will be dependent upon the number of
                  animals involved, the extent of oiling, the physiological condition of the animals, and the experience of the
                  people undertaking the rehabilitation program (USDOI, MMS, 1987a).
                      Wildlife researchers are currently in disagreement about the effectiveness of Exxon's $18 million otter
                  rescue effort following the 1989 Erron Valdez oil spill in Prince William Sound, Alaska. Some researchers
                  question the value of such a research effort, particularly for lightly oiled otters, as prior research had shown
                  that lightly oiled animals could recover without any treatment and that the stresses of capture, transportation,
                  and cleaning itself may have been unnecessarily disruptive.
                      The current RCP for the Region VI Regional Response Team contains Annex 7, recognizes the importance
                  of responding to contamination of waterfowl, and designates the FWS and names contacts for initiating bird
                  collection and cleaning activities. The current RCP for the Region IV Regional Response Team contains no
                  special Annex but lists the NPS and FWS as contacts for responding to potential impacts to sensitive resources,
                  including bird rookeries, which are used at the time of an oil spill to determine where lines ot response should
                  be placed.
                      The Oil Pollution Act of 1990's revisions to the Federal Water Pollution Control Act require that a fish
                  and wildlife response plan be developed, in consultation with the FWS, NOAA, and other interested parties
                  (including State fish and wildlife conservation officials), for the immediate and effective protection, rescue, and
                  rehabilitation of fish and wildlife resources or their habitats in the event of an accidental discharge.
                  Consequently, some of the planning efforts currently identified in this section may change somewhat dependent
                  upon the findings resulting from the development of this plan.
                      Because of the less confined nature of coastlines and marshes, aircraft would probably be of most value
                  for the initial dispersal of birds. If the section of coastline that was oiled or about to be oiled was extensive,
                  use of aircraft would probably be the only practical dispersal method, and numerous aircraft would be
                  necessary.
                      Deterrent methods and devices would need to be deployed along the shore in order to prevent birds from
                  entering the contaminated water. Shell crackers, exploders, lights, reflectors, and mortars, together with
                  continued use of aircraft, would be standard approaches. Distress and alarm calls would be useful if calls of
                  the appropriate species existed and were available. The major limiting factors would be the logistical problems
                  of deploying and operating a sufficient number of devices (Koski and Richardson, 1976).
                      The most effective dispersal method offshore would probably be the use of aircraft. However, some
                  species of seabirds are more likely to dive than to fly when an aircraft approaches, and some molting waterfowl
                  would be unable to fly. Low-altitude (effective) operations would be impossible at night. Searchlights mounted
                  on boats and mortars, rockets, flares, and shell crackers fired from boats would be useful at night, but their
                  effectiveness in cases of large spills would be limited. Because of their large area of coverage, rockets and
                  mortars would probably be more useful than shell crackers and flares both by day and by night. Clean Gulf
                  Associates currently stockpiles a total of 10 sets of 12 bird scare guns strategically located at their bases in Port
                  Aransas and Galveston, Texas; Intracoastal City, Venice, and Grand Isle, Louisiana; and Panama City, Florida.
                  It is recommended that this equipment be manned continuously and that the guns be alternately turned on and
                  off every hour in order that their use would remain effective in scaring birds from oiled areas.
                      It is possible that creation of lure areas away from the contaminated area might attract birds out of the
                  hazardous zone. The obvious approach would be to feed seabirds by throwing fish and other foods into the
                  sea from a boat However, it is quite probable that this would attract more birds into the general area of the
                  oil spill and ultimately increase rather than decrease mortality. It is also possible that boats working in or near










                                                                                                                         IV-153

               the spill for cleanup or even deterrent purposes might unintentionally attract seabirds, which commonly fly
               toward boats (Koski and Richardson, 1976).
                   The FWS has designated contacts in Clear Lake, Texas; Lafayette, Louisiana; Daphne, Alabama; and
               Panama City, Florida, who act as field coordinators for any waterfowl-rehabilitation actions. These coordinators
               can call upon the services of any local FWS office for assistance and equipment. The FWS also maintains a
               dedicated spill-response trailer in Daphne, Alabama, which contains equipment needed to prevent bird
               contamination or to care for oiled birds. This center serves the Gulf Coast region and can be relocated to a
               spill site upon demand. The FWS in Texas has an extensive oiled bird-rehabilitation program. The CGA has
               a movable waterfowl rehabilitation station located in Grand Isle, Louisiana. Extensive information on the use
               of this rehabilitation station is provided in Volume I of the CGA Operations Manual (CGA, 1989). This
               waterfowl rehabilitation station has physical space inside for up to two dozen birds, depending upon the species,
               degree of recovery, and aggressiveness. If it is decided to expand the station, then up to 200 game-size birds
               can be accommodated. The expanded, fenced enclosure will accommodate several hundred more. The CGA
               station is designed to complement a larger and more permanent facility that would be established based upon
               the siting, personnel, and equipment guidelines recommended by the International Bird Rescue Center of
               Berkeley, California. Approximately 350 gallons of a recommended cleanser, enough to cleanse 1,000 birds,
               is stockpiled by CGA_
                   To care for 50, 100, and 500 birds in need of immediate treatment poses severe logistical and equipment
               challenges. To care for 100 birds over a single day would require three 8-hour shifts with an absolute minimum
               of 25 people per shift to provide medical care, wash teams, rinse teams, and facilities management. Cleaning
               teams would need 8,000 gallons of hot water under pressure, and provision would have to be made for
               environmentally acceptable disposal of 5,000 gallons of oily, soapy waste water. Compliance with OSHA
               requirements, human safety protocols, liability insurance, damage assessment protocols, and techniques for
               preventing animals from becoming contaminated would also need to be considered.
                   Survival of rehabilitated oiled birds may vary from 30 percent (Sims, 1970) to 90 percent (Mueller and
               Mendoza, 1983). The success of rehabilitation is primarily due to three factors: advance preparation in
               stockpiling supplies and training volunteers; the availability of a cleanup station with adequate indoor space,
               hot running water, and outdoor pens; and, most importantly, the efforts and cooperation of willing volunteers
               and the government agencies involved (Mueller and Mendoza, 1983). When the rehabilitation effort is
               managed by an experienced oil-spill response team, oiled bird rehabilitation has been carried out with particular
               success in Anaddae species, averaging over 90 percent release of ducks and geese.

               E Recent Developments in Spill-Response Planning/Capabilities

                   In light of all the recent tanker spills occurring in the U.S. coastal waters since the Eaon Valdez incident
               in March 1989, much effort has been expended from the national to the local level in assessing the adequacy
               of the country's spill response planning and capabilities. As discussed throughout Section IV.C.5., the
               implementation of the recently enacted Oil Pollution Act of 1990 could greatly alter the country's existing oil-
               spill response planning structure and response capability. This section provides an update on other recent oil-
               spill response capability related developments, particularly those ongoing by the National Response Team
               (NRT), MMS, USCG, USEPA, and the Marine Spill Response Corporation.

               National Response Team

                   In May 1989, the National Response Team issued its Report to the President on the Erxon Valdez spill
               (Skinner and Reilly, 1989). Besides summarizing the status of the spill, the NRT identified actions that they
               felt should be taken to improve the nation's preparedness for spill response. They recommended a better
               response coordination between Federal, State, and local authorities, especially in regard to the concerns of
               States; that the National Contingency Plan needs to be changed; that oil spill planning should better
               incorporate the care of wildlife and should prepare for and mitigate for wildlife impacts; that exercises to test
               contingency plans should be conducted; and that more research should be conducted into improving cleanup










                  IV-154

                  technology. The NRT, under the leadership of the USCG, finalized a nationwide review of contingency plans
                  by the entire Federal Government, including the 14 agencies that makeup the NRT and all of the U.S. Coast
                  Guard's RRT. The review, which included a total of 75 reports from these various agencies, was directed
                  toward examining the use of worst-case scenarios to ensure realistic planning, examining the adequacy of
                  equipment and personnel for an effective response, and the importance of well-defined organizational
                  responsibilities. The final report was published in October 1990.

                  Minerals Management Service

                      On April 18, 1989, the Secretary of the Interior directed MMS to review current oil-spill planning, response
                  requirements, and practices for OCS oil and gas operations. As a result of this review, MMS has undertaken
                  a number of measures.
                      On April 18, 1989, MMS announced that they will be conducting a stepped-up series of surprise visits by
                  inspectors to OCS drilling rigs and production platforms, and on May 30, 1989, the MMS Gulf of Mexico OCS
                  Region informed industry, through a Letter to Lessees, that unannounced drills would occur. The MMS Gulf
                  of Mexico OCS Regional Office finalized procedures for various types of oil-spill response drills and initiated
                  the unannounced drill program in the summer of 1989.
                      On May 13, 1991, the MMS published in the Federal Register the Notice of Final Rule regarding changes
                  in the methods by which MMS would assess civil penalties. This notice revised rules governing civil penalty
                  assessment under section 24(b) of the OCSLA (43 U.S.C. 1350(b)) to implement revised authority for the
                  Secretary of the Interior to assess civil penalties for failure to comply with regulations governing oil and gas
                  and sulphur operations in the OCS. This action will enable MMS to assess a civil penalty without first
                  providing notice and time for corrective action in cases where the failure constitutes or constituted a threat of
                  serious, irreparable, or immediate harm or damage to life, property, any mineral deposit, or the marine, coastal,
                  or human environment.
                      The MMS has initiated a $6 million research program on oil-spill technology research. The MMS remains
                  a lead agency in the continuing technology assessment and research to improve oil-spill response capabilities.
                  The MMS has long been involved in oil-spill response research, although the program has been heightened
                  somewhat in light of the recent large oil spills from tankers. Current research projects include the development
                  of an airborne, laser-assisted fluorosensor; the development of improved strategies for gaining an improved
                  understanding of the fate and behavior of spilled oil as it affects response strategies; the development of safe
                  and environmentally acceptable strategies to burn spilled oil in situ; an evaluation of the effectiveness of
                  different shoreline cleanup techniques and the environmental damage resulting from each of the techniques;
                  the development of a prototype high-speed, water jet barrier boom; the development of realistic laboratory
                  effectiveness test protocol for dispersants; testing of new oil-spill chemical agents that are nondispersants; the
                  investigation of new chemical dispersant formulas that promise greater effectiveness; and the development of
                  a portable oil analysis kit for responders.
                      In addition, as of April 27, 1990, the management of the Oil and Hazardous Materials Simulated
                  Environmental Test Tank (OHMSETT), located in Edison, New Jersey, was transferred to MMS for purposes
                  of research to improve oil-spill response and capability. It was reopened in Fall 1991. The reactivation of this
                  facility will allow the development of standard testing protocol to determine the efficiency and effectiveness
                  of response equipment and products, such as skimmers and dispersants, and the evaluation of subsurface oil
                  detection and collection concepts. The development of standard text procedures will ensure that only the
                  appropriate equipment is approved for use in oil spill contingency plans.
                      The MMS has also recently developed guidelines for equipment inspections and for reviewing and
                  approving OSCP's. All OSCP's have been reviewed to ensure an appropriate response to the largest possible
                  OCS oil spill. The Gulf Office is currently assessing oil-spill response times on a case-by-case basis for
                  adequacy in the light of potential damage and will continue to assess the effectiveness of measures such as
                  CGA's use of identified and equipped vessels at designated sites offshore to reduce response times in the Gulf
                  of Mexico.











                                                                                                                           IV-155

                U.S. Coast Guard


                     The OPA is the largest single legislative tasking that the USCG has ever received. The work required to
                implement the Act is'extensive. The following discussion is limited to just a few of the many tasks assigned
                to the USCG through implementation of OPA. Required organizational actions include the establishment of
                two special staff elements to facilitate OPA implementation; a National Pollution Funds Center to develop and
                administer those parts of OPA dealing with financial responsibility and the Oil Spill Liability Trust Fund; and
                a separate multidisciplinary Headquarters staff to write implementing regulations and to oversee and coordinate
                the multiple studies and reports required by the Act.
                     The USCG has also commissioned a third strike team at Fort Dix, New Jersey, on September 5, 1991.
                New equipment is being procured for the strike teams and full-response capability is expected in the
                FalWinter of 1992. The National Strike Force Coordination Center was also commissioned on September
                3, 1991, in Elizabeth City, North Carolina. In addition, the USCG is establishing District Response Groups
                that will consist of all USCG personnel, vessels, and equipment assigned to the District as well as prepositioned
                response equipment that is strategically located within the District. In order to provide a ready supply of
                equipment necessary to combat a spill, the USCG has selected 19 sites nationwide for locating spill-response
                equipment. The criteria for this site selection included spill probability and environmental sensitivity.
                Equipment to be procured for these sites is discussed in Section IV.C.5.d.(1).         In addition the USCG is
                procuring a small amount of additional equipment to be located at numerous other sites not located within
                proximity of the 19 selected equipment sites.
                     The USCG and USEPA have been co-chairing monthly meetings to draft a revised National Contingency
                Plan for oil spills. Work also continues between USEPA and USCG to draft contingency plans for response
                areas. The USCG is delegated the responsibility of designating areas in the coastal zone for which area
                committees are to be established. These areas are also designated as those requiring Area Contingency Plans.
                Similar mandates are given to USEPA for inland areas. The initial designation of these areas would make the
                areas the same as those already established by Regional Response Team Contingency Plans; however, if
                required, additional subareas will be established after the Area Committee review. The USCG is also in the
                process of developing requirements for tank vessel response plans.
                     Title VII of OPA establishes an Interagency Coordinating Committee on Oil Pollution Research charged
                with coordinating a comprehensive program of research, technology development, and technology
                demonstration among Federal agencies in cooperation with industry, universities, research institutions, State
                governments, and other countries. The Committee is chaired by the Department of Transportation (USCG).
                In addition to establishing the Interagency Committee, the Act addresses specific Federal activities including
                development of a Federal Oil Pollution Research and Development (R&D) Plan outlining a comprehensive
                five-year effort to upgrade technology for oil spill prevention and response, a program to study the effects of
                specific oil spills to be monitored by the Department of Commerce and USEPA, demonstration projects in
                specific port areas to be conducted by the USCG in coordination with other agencies (New Orleans has been
                selected as the site of one of these demonstration projects), and a regional grants program addressing regional
                aspects of oil pollution such as prevention, removal, mitigation, and the effects of discharged oil on regional
                environments. Presently, there are 19 member agencies and 4 ex-officio member agencies participating on the
                Committee and involved in preparing the Interagency Oil Spill R&D Plan. At this time, the Committee has
                completed the initial draft of the Comprehensive 5-Year Oil Pollution R&D Plan. The Plan is currently being
                reviewed within the Executive Branch prior to submission to Congress.
                     Some of the significant research efforts underway include (1) a major joint effort between USCG and
                NOAA to develop an integrated, prototype Decision Support System for ofl-spill response that will provide
                OSC's and SSC's with detailed maps of specific areas showing attributes relevant to managing spill-response
                operations, and databases with accurate and accessible technical information for spill response; (2) a study that
                focuses on the short-term upgrade of its oil-spill surveillance capability; (3) a study that focuses on a longer
                term upgrade within USCUs multi-mission remote-sensing surveillance system; (4) participation in the project
                to develop an oil-spill thickness sensor; (5) participation in the reopening of the OHMSETT facility in
                Leonardo, New Jersey; (6) participation in a joint project with the U.S. Navy to streamline the current oil-spill
                recovery process by developing technologies to separate oil from water and provide for temporary storage of










                 IV-156

                 recovered off and debris and to test and improve vessel-of-opportunity skimming systems; and. (7) participation
                 in the ongoing in-situ burn work.

                 US. Environmental P@otection Agency

                     As implementation of OPA continues, the oil-spill response program at USEPA is expected to expand to
                 meet its increased responsibilities. The OPA mandates that the NCP be revised to address a number of new
                 issues, includingarea contingency planning and response procedures for"worstcase discharges," and "substantial
                 threats to health or welfare." The Act also added the requirement that spill mitigating devia-,s and substances
                 be addressed in the NCP Product Schedule where appropriate. The Product Schedule is currently a list of
                 dispersants and other chemicals that may be used in spill mitigation. The USEPA has formed workgroups to
                 address revisions to the NCP in general and to the Product Schedule specifically. In addition, USEPA is
                 reconsidering the current toxicity and effectiveness tests for dispersants under Subpart J of the NCP. The
                 USEPA may develop effectiveness criteria for products on the Product Schedule,which may reduce the number
                 of products on the Schedule.
                     Activities underway to recognize the environmental significance of preventing oil spills include providing
                 the funding to implement the programs already in place, coordinating with agencies and departments
                 responsible for other aspects of oil pollution, promulgating additional regulations, issuing guidance, and
                 conducting training. Currently, regulations mandated by OPA are being developed. The USEPA intends to
                 develop a set of factors to determine which onshore fixed facilities must submit plans.
                     In the area of bioremediation, USEPA is undertaking a major R&D program to assess and improve this
                 technology. This includes continuing post Evron Valdez bioremediation research and development of a
                 bioremediation use and monitoring protocol for application of bioremediation agents on subsequent spills. The
                 USEPA has developed interim guidelines to help response officials consider bioremediation in their oil spill
                 contingency plans. The guidelines are offered as a way for spill responders to collect necessary information
                 on bioremediation to use in their contingency plan.
                     The USEPA is also developing a series of testing protocols to identify safe, effective, and efficient
                 bioremediation techniques to clean up oil spills. The agency is putting together a database of available
                 bioremediation technologies for use by spill responders to match a specific product with a specific spill. To
                 support more extensive test and evaluation of bioremediation products, USEPA is developing a three-tiered
                 protocol including initial vendor tests, more extensive laboratory effectiveness and toxicity tests, and microcosm
                 tests. The establishment of an USEPA bioremediation testing center is also being considered.

                 Marine Spill Response Corporation

                     The Petroleum Industry Response Organization, first formulated in June, 1989 by the American Petroleum
                 Institute, has been renamed the Marine Spill Response Corporation (MSRC) because the organization's
                 potential clientele has since expanded beyond the conventional oil industry. The MSRC Ls an independent,
                 privately financed, nonprofit catastrophic oil-spill response organization in the U.S. Membership in MSRC is
                 now also open to independent tanker operators, public utilities, or any company that handles petroleum or
                 petroleum products in quantity over coastal waters. Implementation of the MSRC organizition was on hold
                 pending the outcome of the Off Pollution Act of 1990. Since the Act limits the liability of responders under
                 Federal law, MSRC is now in the process of activation and expects to be fully operational by March 1993.
                     Since 1989, the costs and size of the organization have increased tremendously-, equipment, maintenance,
                 research, and personnel costs for the first 5 years are now estimated to be more than S" million, three times
                 the original estimate. The MSRC will be able to respond to large spills in offshore and tidal waters along the
                 Pacific, Atlantic, and Gulf coasts, plus Hawaii, the U.S. Virgin Islands, and Puerto Rico. The MSRC win be
                 available to help with smaller spills whenever the USCG determines that local response capabilities are
                 inadequate. The organization will augment, not replace, existing local spill co-ops and response coordinators.
                 A separate nonaffiliated corporation, the Marine Preservation Association (MPA), will fund. the MSRC. The
                 MPA, whose membership will include owners, shippers, and receivers of crude oil and petroleum products, will
                 not have any direction over MSRC operations.










                                                                                                                               IV-157

                     The MSRC is headquartered in Washington D.C. with five regional centers each capable of responding
                 to a 9-million-gallon oil spill. Each regional center will have four to six prestaging areas where responders will
                 warehouse equipment and, in some instances, vessels and response personnel. The five general areas for
                 response centers and their prestaging areas include (1) northeast region, with a response center in the New
                 York/New Jersey metropolitan area; (2) southeast region, with a response center in Port Everglades, Florida;
                 (3) Gulf region, with a response center in Lake Charles, Louisiana; (4) southwest region, with a response center
                 in the Port Hueneme area of Southern California; and (5) northwest region, with a response center in Seattle,
                 Washington. The prestaging areas in the Gulf region include Mobile, Alabama; Venice, Louisiana; Galveston,
                 Texas; and Corpus Christi@ Texas. The MSRC will employ a full-time staff of 400 employees and will require
                 more than $315 million worth of initial equipment, including booms, skimmers, vessels, trucks, dispersants, and
                 wildlife rehabilitation and shoreline restoration tools.
                     The MSRC has recently purchased more than $216 million worth of vessels and equipment. Contracts for
                 the construction of sixteen 210-ft offshore response vessels have been issued. The vessels will be deployed
                 around the U.S. and will be similar in design to standard offshore supply boats with deckspace to deploy a full
                 range of spill-response equipment. The MSRC has purchased 16 over-the-side high capacity skimmers and 16
                 boom containment systems designed to accumulate large quanities of oil in a V-shaped pocket to facilitate
                 recovery. This equipment will be installed on each of the 16 response vessels. The over-the-side skimmers are
                 reported to have a manufacturer's advertised removal capacity of up to 2,200 bbl per hour. Also to be
                 purchased are 10 wier boom skimming systems and two heavy oil recovery skimmers that are transportable
                 systems which can be deployed on a variety of platforms. A total of 10 viscous oil transfer pumps, 7 high
                 capacity transfer pumps, 30 vacuum skimmers which have particular application in shallow water and for
                 shoreline cleanup, and 20 miles of intertidal boom is also being procured.
                     The MSRC is developing a computer assisted spill management system, which will make a major
                 improvement in the way large spills are fought in the future. Such system elements as spill tracking, resources
                 at risk, and logistics are some of the kinds of information that will be available, on a real time basis, to regional
                 general managers and the government OSC to facilitate decision making on-scene.
                     The organization will also provide a program to audit on a continuing basis, the readiness of the response
                 forces to meet their objectives; and an active research and development program. The research and
                 development program objectives are to improve the basic information about spills and the technology of oil-
                 spill response and cleanup. Research programs will be funded to study chemical and biological effects of
                 spilled oil on the environment, techniques for on-water recovery and treatment, and the prevention and
                 mitigation of shoreline impacts. Patents or royalties will be donated to the public domain.
                     The MSRC successfully carried out field tests evaluating various remote airborne sensing devices. This is
                 part of a larger project the MSRC is aggresively pursuing to develop an integrated remote sensing and imaging
                 processing system. The goal is to provide the oil spill responder ihe ability to see oil on the sea under adverse
                 conditions not currently possible.
































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