    [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.