[House Document 105-144]
[From the U.S. Government Publishing Office]



105th Congress, 1st Session  - - - - - - - - House Document No. 105-144


 
                       BEACH NOURISHMENT PROJECT

                               __________

                             COMMUNICATION

                                  from

  THE ACTING ASSISTANT SECRETARY (CIVIL WORKS), THE DEPARTMENT OF THE 
                                  ARMY

                              transmitting

A REPORT ON THE STORM DAMAGE REDUCTION AND SHORELINE PROTECTION PROJECT 
   FOR REHOBOTH BEACH AND DEWEY BEACH, DELAWARE, PURSUANT TO SECTION 
        101(b)(6) OF THE WATER RESOURCES DEVELOPMENT ACT OF 1996





   October 6, 1997.--Referred to the Committee on Transportation and 
               Infrastructure and ordered to be printed.


                            C O N T E N T S

                               __________
                                                                   Page
Letter of transmittal............................................   vii
Comments of the Office of Management and Budget..................    ix
Comments of the State of Delaware................................     x
Comments of the Department of the Interior.......................    xi
Comments of the Environmental Protection Agency..................   xii
Report of the Chief of Engineers, Department of the Army.........     1
Report of the District Engineer..................................
    Addendum.....................................................     6
    Syllabus.....................................................     7
    Pertinent Data...............................................
INTRODUCTION:
    Study Authority..............................................     9
    Study Purpose and Scope......................................    10
    Description of the Study Area................................    11
    Prior Studies, Reports and Related Projects..................    15
    Related Institutional Programs...............................    18
    Problem Identification.......................................    20
EXISTING CONDITIONS..............................................    24
    Physical Setting.............................................    24
    Numerical Modeling of Shoreline Change.......................    32
    Social and Economic Setting..................................    43
    Existing Environmental Conditions............................    46
    Existing Cultural Resources..................................    60
WITHOUT-PROJECT FUTURE CONDITIONS................................    62
    Without-Project Hydraulic Analysis...........................    62
    Without-Project Economic Analysis............................    82
PLAN FORMULATION.................................................    90
    Planning Needs, Objectives and Constraints...................    90
    Plan Formulation.............................................    93
    Cycle 1--Initial Screening of Solutions Considered...........    94
    Cycle 2--In Depth Evaluation and Screening of Solutions 
      Considered.................................................   101
    Plans Considered in Cycle 2..................................   109
    Solutions Recommended for Optimization Cycle 3...............   116
    Cycle 3--Optimization of the Selected Alternative Solutions..   118
    Optimization of Alternative Plans............................   122
SELECTED PLAN....................................................   132
    Project Impacts..............................................   142
    Cost Apportionment...........................................   145
    Local Cooperation............................................   149
RECOMMENDATIONS..................................................   263

                            List of Figures

FIGURE 1 Map of Delaware Ocean Coast.............................    12
FIGURE 2 Map of Coastal Barrier Resources System.................    13
FIGURE 3 Rehoboth Beach Henlopen Hotel, March 1962...............    21
FIGURE 4 Dewey Beach, January 1992...............................    21
FIGURE 5 Dewey Beach, January 1992...............................    22
FIGURE 6 Dewey Beach, December 1992..............................    22
FIGURE 7 Map of Reaches Along the Delaware Ocean Coast...........    29
FIGURE 8 Map of Rehoboth Beach Showing Groin Locations...........    39
FIGURE 9 Map of Dewey Beach Showing Outfall Locations............    42
FIGURE 10 Map Giving Location of Borrow Area.....................    47
FIGURE 11 Map Showing Benthic Sampling Locations.................    55
FIGURE 12 Map of Profile Lines Along Study Area..................    63
FIGURE 13 Historic Profile Data..................................    65
FIGURE 14 Calibration/Verification Run Profile 140...............    73
FIGURE 15 Calibration/Verification Run Profile 230...............    74
FIGURE 16 Calibration/Verification Run Profile 125...............    75
FIGURE 17 Rehoboth Beach, Without Bulkhead 100 Year Storm Erosion    76
FIGURE 18 Rehoboth Beach, With Bulkhead 100 Year Storm Erosion...    77
FIGURE 19 Dewey Beach, Without Bulkhead 100 Year Storm Erosion...    78
FIGURE 20 Dewey Beach, With Bulkhead 100 Year Storm Erosion......    79
FIGURE 21 Typical Transect Schematic.............................    86
FIGURE 22 Two Wave Conditions Analyzed for Storm Damage..........    87
FIGURE 23 Borrow Area, Sand Deposits and Vibracore Locations 
  Along the Delaware Ocean Coast.................................   104
FIGURE 24 Native Beach Sampling Lines............................   106
FIGURE 25 Typical Section of Berm................................   112
FIGURE 26 Typical Section of Berm and Dune.......................   113
FIGURE 27 Map of Dewey Beach Showing Location of Cycle 2 
  Alternative--Proposed Groin Field..............................   114
FIGURE 28 Cycle 2 Alternative--Proposed Groin Cross Section......   115
FIGURE 29 Cycle 2 Alternative--Typical Section of Bulkhead.......   117
FIGURE 30 Map of Rehoboth Beach Showing the Selected Plan........   134
FIGURE 31 Map of Dewey Beach Showing the Selected Plan...........   135
FIGURE 32 Selected Plan Design Template for Rehoboth Beach and 
  Dewey Beach....................................................   136
TABLE 1 Prior Studies and Reports................................    15
TABLE 2 Ocean Tide Range.........................................    24
TABLE 3 Ocean Stage Frequency Data...............................    26
TABLE 4 Still Water Elevation vs. Recurrence Interval for Inland 
  Bays...........................................................    27
TABLE 5 Shoreline Reach Identification for Atlantic Coast of 
  Delaware.......................................................    30
TABLE 6 Historical Shoreline Change..............................    32
TABLE 7 Volumetric Sediment Budget Rates.........................    36
TABLE 8 Rehoboth Beach, Existing Beach Groins....................    38
TABLE 9 Rehoboth Beach, Existing Bulkheads.......................    41
TABLE 10 Total Population........................................    44
TABLE 11 Per Capita Income.......................................    45
TABLE 12a Analysis Profile Designation...........................    69
TABLE 12 Coastal Structure Locations and Failure Criteria........    70
TABLE 13 Predicted Erosion Positions for Without-Project 
  Conditions.....................................................    80
TABLE 14 Inundation Frequency Stage Wave Setup...................    81
TABLE 15 Predicted Wave Impact Zone Positions for Without-Project 
  Conditions.....................................................    83
TABLE 16 Inundation Analysis Results--Profile 7..................    84
TABLE 17 Annualized Damages by Category and Emergency Cleanup 
  Costs..........................................................    88
TABLE 18 Cycle 1--First Level Screening Results..................    95
TABLE 18 Continued...............................................    96
TABLE 19 Survey Line Material Composite Summary..................   105
TABLE 20 Hen and Chickens Shoal Borrow Area Characteristics......   108
TABLE 21 Secondary Borrow Area Material Characteristics..........   108
TABLE 22 Cycle 2 Screening Results...............................   110
TABLE 23 Matrix of Initial Alternatives..........................   120
TABLE 24 Alternative Plans Considered............................   121
TABLE 25 Nourishment Estimates...................................   123
TABLE 26 Alternative Project Costs...............................   126
TABLE 27 Storm Damage Reduction by Alternative...................   128
TABLE 28 Dewey Beach, Benefit/Cost Matrix........................   129
TABLE 29 Rehoboth Beach, Benefit/Cost Matrix.....................   130
TABLE 30 Nourishment Estimate With Addition of Groin Field in 
  Dewey Beach....................................................   131
TABLE 31 Periodic Nourishment Optimization.......................   138
TABLE 32 Estimated Operation and Maintenance Costs for the 
  Selected Plan..................................................   140
TABLE 33 Average Annual NED Benefits of Selected Plan............   141
TABLE 34 Total First Cost Estimate...............................   144
TABLE 35 Benefit/Cost Comparison for the NED Plan................   146
TABLE 36 Basis for Cost Sharing the Selected Plan................   147
TABLE 37 Cost Sharing for the Selected Plan......................   148

                           List of Appendices

                   (Only Appendices D and E printed)

APPENDIX A ENGINEERING TECHNICAL APPENDIX.
APPENDIX B ECONOMIC APPENDIX.
APPENDIX C UNITED STATES FISH AND WILDLIFE SERVICE COORDINATION.
APPENDIX D PERTINENT CORRESPONDENCE..............................   264
APPENDIX E REAL ESTATE PLAN......................................   292
APPENDIX F PUBLIC ACCESS PLAN.
APPENDIX G PUBLIC REVIEW COMMENTS AND RESPONSES.





                            
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