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

            A Study of Shore Erosion
     Management Options in South Carolina

                                 COASTAL ZONE
                              INFORMATION CENTER

    The South Carolina Sea Grant Consortium

                                                July, 1981
                                                SC-SG-81-1

                                                   COASTAUL ZOE

                                               INFORMATIoN CENTER

                           A STUDY OF SHORE EROSION MANAGEMENT

                           ISSUES AND OPTIONS IN SOUTH CAROLINA

                                     James B. London
                                     John S. Fisher
                                     Gary A. Zarillo
                                   John E. Montgomery
                                     Billy L. Edge

                         This project was designed and managed by
                          The South Carolina Sea Grant Consortium
                               with funds provided by the
                             South Carolina Coastal Council

                                      July, 1981
                                         July 8property of CSC Library
    V)Du

            Se  � NDUS Department of Commerce
    -  , 4                                        NOAA Coastal Services Center Library
                    -Joh~~~  Q                 2234 South Hobcs  Avenue
             3I) ~~~ - ~~ ~Charleston, SC  29405-2413
     ~_   !,j!

                                            RESEARCH STAFF

                John M. Armstrong, Director, South Carolina Sea Grant Consortium
                John W. Brown, Resource Economist, National Marine Fisheries Service
                and the South Carolina Sea Grant Consortium
     5          ~~~James S. Dykes, Graduate Research Assistant, The Center for
                Metropolitan Affairs and Public Policy, The College of Charleston
                M. Richard DeVoe, Assistant to the Director, South Carolina Sea Grant
    I         ~ ~~Consortium
                Billy L. Edge,* Professor, Department of Civil Engineering, Clemson
                University
     I        ~ ~~John S. Fisher,* Associate Professor, Department of Civil Engineering,
                Clemson University
     5          ~~~Miles 0. Hayes, Professor, Department of Geology, and Director, Coastal
                Research Division, University of South Carolina
                Rick Hepfer, Student Assistant, School of Law, University of South Carolina
    *1        ~ ~~James C. Hite, Professor, Department of Agricultural Economics and Rural
                Sociology, Clemson University
                Diane C. Hudgins, Graduate Research Assistant, The Center for Metropolitan
     I        ~ ~~Affairs and Public Policy, The College of Charleston
                Wyatt Hunter, Graduate Research Assistant, Department of Civil Engineering,
     5          ~~~Clemson University
                Karen L. Jewell, Graduate Research Assistant, The Center for Metropolitan
                Affairs and Public Policy, The College of Charleston
     I        ~ ~~James B. London,** Assistant Professor, The Center for Metropolitan Affairs
                and Public Policy, The College of Charleston
                Joseph S. Lyles, Research Assistant, The Center for Metropolitan Affairs
     I        ~ ~~and Public Policy, The College of Charleston
                James P. May, Assistant Professor, Department of Chemistry, The Citadel
     3          ~~~John E. Montgomery,* Associate Dean, School of Law, University of South
                Carolina
                Frank W. Stapor, Formerly Assistant Marine Scientist, South Carolina
                Marine Resources Research Institute
                Roger R. Stough, Director, The Center for Metropolitan Affairs and Public'.
     5          ~~~Policy, The College of Charleston
                Gary A. aarillo,* Research Scientist, Department of Geology, University of
                South Carolina

                   * Major Author

                  ** Major Author and Compiler

                                              FOREWORD

     5             ~~~~The study described in this report is the first truly comprehensive

              examination of the problems of shore erosion in South Carolina. While

    5         ~~~there have been many excellent efforts carried out on various individual

              problems, this project has brought together the many geological, engineering,

              economic,and legal issues into one analysis.
     *             ~~~~The basic purpose of the report is to provide a basis for discussion

              of issues and options related to shore erosion. Several recommendations

    5         ~~~are made regarding state and local policy, research, and technical assistance.

                   The project was accomplished by a team of specialists from each of

    I         ~~~the Consortium's seven member institutions.  The project was structured,

    5         ~~~assembled, and coordinated by the Consortium as one of several projects

              underway which are examining coastal and marine issues in the state.

                                                   John M. Armstrong
                                                   Director
                                                   South Carolina Sea Grant Consortium

          I                           ~~~~~~~~EXECUTIVE SUMMARY

                The damage associated with shoreline erosion has increased signifi-

           cantly in recent years. Although these erosional trends have been

    I      ~~long-term, related property loss has accelerated largely due to increased

    I ~~activity along the coast. In response to this problem, federal, state,

           and local entities are reevaluating existing policy and formulating new

            approaches to more effectively manage coastal resources. It is for this

           reason that the nresent study was undertaken with atte'ntion. given to shore-

    I ~~line management options applicable to conditions in the State of South

    I ~~Carolina.

                 In order to effectively manage coastal resources, it is appropriate

    �      ~~first to examine the processes influencing beach systems.  Studies of the

            South Carolina coast indicate that the shoreline is transitional between

            the wave-dominated North Carolina coast and the tidal-dominated Georgia

            coast. The arcuate strand along the northern coast is characterized by

            infrequent inlet formations. Although relatively stable from a long-term

    II ~perspective, beaches of the arcuate'strand are subject to short-term ero-

            sional trends as a result of storm and wave influence.

                 The- central portion of the South Carolina coast is dominated by the

    N      ~~Santee River Delta.  This'section of the coast is characterized by rapidly

    U ~~retreating shorelines due to the loss of sediment supply since the damming

    5      ~~of the Santee River in 1942 and the rediversion of part of its flow into

            the Cooper River. From Bull Bay to the Georgia border, the coast is

    �      ~~comprised of barrier islands separated by frequent tidal inlets and larger

            estuarine systems. The majority of these islands are comparatively stable

            beach ridge barriers, but several of the islands may be classified as ero-

    3 ~~sional or transgressive.

         Long-shore transport is predominantly to the south along the South

    Carolina coast, yet local direction reversals may occur on the downdrift

    side of inlets. Inlet formation is an integral determinant of sediment

    deposit; short-term shifts in inlet location due primarily to storm-

    effects may contribute to localized erosion at adjacent beaches. On

    balance, the historical trend of sea level rise continues to influence

    long-term erosion rates; yet, tidal, wave, and littoral influences may

    combine to reverse this trend in some locations.

         Recently, a  better public understanding of coastal dynamics and

    the observation of large-scale property loss have kindled a design with

    nature approach to coastal development.  As a long-term approach to

    alleviate the potential for property loss and for interference with the

    natural system, the concept has considerable merit. Yet, where develop-

    ment has occurred previously'and extensive property loss is imminent,

    short-term solutions to save property and/or beach areas bear considera-

    tion. In addition, future plans will continue to be subject to error

    given the uncertainty related to the coastal system.I

         From an engineering perspective, the most often considered alterna-

    tives for large-scale erosion control include:

                 seawalls,
                 bulkheads,
                 revetments,
              5  groins,

                 jetties and inlet control, and
                 beach nourishment.

    Seawalls, bulkheads, and revetments are structural solutions intended to

    prevent further erosion and/or maintain property. Seawalls are the most

    substantial of the three types of structures being designed to withstand

            *~~~~~~~~~~~~~~~~~~~~~~

    wave attack. Bulkheads, generally consisting of wood pilings, and revetments,

    generally of stone rubble, are designed to maintain property lines. Al-

    though effective in some circumstances, each of these types of structure

    may accelerate erosion on the front beach and adjacent properties.

         Groins and jetties are often employed to capture littoral sediment

    flow, causing accretion on the updrift side of the structure. The result

    is typically a loss of sediment to the downdrift side where erosion

    is accelerated. Inlet control also is designed to influence sediment

    transport by altering the volume and speed of discharge.

         Beach nourishment is increasingly being employed as a non-structural

    solution to shoreline erosion.  By transporting sand from an offshore

    borrow site, the technique is an imitation  of nature.  Often nourishment

    is combined with structural solutions such as groins or offshore break-

    waters.  Although effective,'nourishment is generally expensive and

    requires periodic replenishment.

         In addition to engineering solutions, management techniques are being

    used increasingly to direct development away from potential hazard areas.

    Although it is said that coastal sediment budgets are in continous equili-

    brium, development patterns are often out of equilibrium.  Much of this

    situation relates to the rapid development that has occurred in recent

    years. Postwar development has been stimulated by a number of private

    incentives, including:  1)  growth in personal income, 2)  a shift in the

    geographic distribution of the population, 3)  improved accessibility, and

    4)  learned behavior patterns among users.  In addition, favorable clima-

    tic conditions and a series of government programs have contributed to

    accelerated building patterns.

     I             ~~~~The development of coastal areas has led to collective as well as

    J ~~individual benefit. Accessibility has been increased, and tourism, loca-

              ted predominantly along the coast, represents South Carolina's second

    5         ~~most important industry.  As a result, the value of the beach in terms of

              use and option accounts for significant benefit to both residents and non-

    I         ~~residents.  At the same time, the costs associated with coastal building

    I         ~~patterns have increased.  Perhaps the primary cost peculiar to coastal
              development stems from external effects. Because of the fragile, inter-

    I         ~~related nature of the coastal system, external costs may become
              significant as the system's carrying capacity becomes strained. The re-

    1         ~~maining cost differentials for coastal development are largely

    �         ~~informational or due to risk associated with coastal hazards, including

              beach erosion. While social costs have not been fully considered, public

    I         ~~subsidization, in effect, has lowered the building cost in beach areas.
              At the same time, a lack of adequate information and the collective sha-

    I         ~~ring of risk also have contributed lower perceived costs and often as a

              result to overutilization of the resource.

                   It is argued that resource use is optimal when public subsidization is

    �         ~~equal to the anticipated social benefit accruing from the program.  External

              effects should be minimized by forcing the responsible party to bear full

    I         ~~costs where appropriate.  In many cases, however, the interrelated and fra-

    �         ~~gile nature of the coastal ecosystem require collective control to

              minimize dommunity-wide damage. It is the responsibility of the state as

    3         ~~well as local communities to develop an appropriate framework allowing for

              collective resource use and to provide information permitting rational

    5         ~~decisions to be made.  It is not the responsibility of the public sector,

                                                                   vii

    however, to assume the private risk of development. Within this framework,

    private property owners and communities should be allowed to pursue indi-

    vidual and community interests to the maximum extent possible consistent

    with state policy.

          Current state programs with regard to erosion control stem largely

    from the-Coastal Zone Management Act (1972) and Amendments (1976). Consi-

    dered within the report are existing and proposed institutional frameworks

    at the federal, state, and local levels. Particular attention is given to

    the appropriate role of each jurisdiction and to funding responsibility in

    this regard.

          From a legal perspective, the constitutionality of the setback con-

    cept has been upheld in South Carolina although coastal setback lines have

    not been addressed specifically. It is found, further, that a regulatory

    program promulgated either by the State Coastal Council or on a county-by-

    county level could successfully address the issue of land-use controls with

    minimal legal difficulties. In terms of beach accretion, a difference of

    opinion exists, but the existing decisions conform to the position that

    accreted land belongs to the littoral beach owner.  With respect to en-

    gineering solutions to control coastal erosion, it appears that counties

    under existing law can finance erosion control projects assuming the de-

    termination of benefit can be established in a reasonable fashion.

         With this background, case studies were conducted at four sites

    along the South Carolina coast to determine the feasibility of alternate

    erosion controlprojects at these sites.

                    I                                                     ~~~~~~~~~~~~~~~~~Viii

            The site studies include:

       j              ~~~~. Hunting Island,
                      . Hilton Head,
                      . Pawleys Island, and

                      . Myrtle Beach.
    J      ~~Each case considers beach morphology, engineering alternatives, and project

            evaluation for the site in question. It is found, based upon the existing

    j      ~~data, that beach nourishment appears to be more feasible at Myrtle Beach

            and Hunting Island than at the other. sites, while smaller scale projects

    I      ~~considered at Pawleys Island also may be feasible.  At e ach of the sites, and

    5 ~~particularly at Myrtle Beach and Hilton Head where the most rapid development

            is occuring, management approaches to encourage and/or require development

            to-factor erosional prospects in building patterns are seen as important

            in reducing both long-term property and recreational loss.   Where engineering

    I      ~~options are considered as short-term remedies, more detailed information on

            project costs and site specific erosion effects should be incorporated

            before extensive public monies are committed. Nonetheless, the findings

            serve as a point of departure and as meth odological framiework for similar

            studies at these or other sites.

     I          ~~~In co nclusion, the study strongly recommends that the state clearly

    � ~~define long-run policy and develop appropriate guidelines with respect to

            coastal erosion. From a long-term perspective, it is concluded that the

    � ~~primary functions of the state should be:

                      1) to provide information to individuals and the localities
       5                 ~~~~~allowing more informed decisionsto be made with respect
                          to coastal development,

                      2) to provide guidelines to reduce the potential for and conse-
       I                ~ ~~~~quences of private actions having detrimental effects on
                          adjacent beach properties, and

                      3) to provide for protection and maintenance of the public

       I~~~~~~bah

                                                                   ix

         In order to provide for information exchange, a data collection

    program must be maintained monitoring coastal processes and their expected

    effect upon beach formations. The information accumulated should be

    disseminated through technical assistance programs'for local authorities

    and public forums directed at present and potential beach dwellers as well

    as concerned citizens.

         Because of the volatile nature of the beach system, thebuilding

    patterns of indidviduals may have community-wide impacts detrimentally

    affecting both adjacent property owners and the public beach. To reduce

    the potential for such occurances, it is strongly recommended thatthe

    state as well as local entities enact coastal setback lines applicable to

    new oceanfront development.  Although standard distances from mean high

    water and the primary dune may serve as bases, it is suggested that scientific

    data be incorporated to the extent practicable and that these setbacks

    be reviewed periodically to incorporate new data at specific dates in the

    future.  In addition, a statewide building code should be instituted for

    coastal development, the primary rationale for such a code being that

    high occupancy rates by nonowners and the resale of structures greatly

    alter the issue of risk bearing by private property owners.

         In the short-term, and particularly for development occuring under

    previous institutional arrangements, structural solutions maybe required

    to prevent extensive property loss.  Erosion control projects should meet

    guidelines previously documented (SCCMP IV-4c) and under review.  Additionally,

    a justification indicating that the solution is in the public interest, the

    most feasible alternative, and identifying any detrimental effects to

    adjacent properties and the public beach should be included. Attention should

    be given, in some cases, to property acquisition and relocation where the

                                                                                 x

    3       ~~solution is deemed more appropriate.

     a          ~~~Because localities are more accessible and representative of community

            interests, the development of local erosion control plans should be

            encouraged. Technical assistance for developing such plans should be

            provided through the state's coastal zone management program. Principle

    5~~components of these plans should include:

                        * an identification of legal authorities and
       5                 ~~~~~management responsibilities,

                        * a local setback provision consistent and meeting as a minimum
       I                  ~~~~~standards established-by the state, and

                        * a provision addressing funding for the local share of
       3                  ~~~~~erosion control structures should they be necessary.

            Local setback and permitting authority is suggested to provide for additional

    3 ~~local control as well as responsibility for development practices.

                 Future state funding for erosion'control projects should be contingent

    I ~~upon the development of -responsible local initiative to address erosion

    g       ~~control problems within its jurisdiction.  In terms of state funds of

            erosion control projects, highest priority should be given to public

    I       ~~beaches followed by private beach areas allowing public access..  All
            such programs should be justified as being in the public interest.

                   I                                                         ~~~~~~~~~~~~~~~~~~~~xi

                                      ACKNOWLEDGEMENTS

     j           ~~~As is the rule in such studies, the final product owes much to the
             contribution of a number of individuals. With some reservation for fear
    5       ~~of oversight, the authors wish to acknowledge the following individuals
             and institutions.
                  Primary acknowledgement must be extended to other members of the

             research staff whose combined expertise made the task far more manageable.
             Previous coastal process studies conducted by Dr. Miles Hayes and others

             at the Coastal Research Division at the University of South Carolina
            provided a firm basis on which to develop the present study. Field work
    3       ~~and early working papers by research assistants Karen Jewell and Joseph
             Lyles provided much of the later documentation. Additionally, support
             within each of the member institutions as well as the individual depart-
            ments and centers bears mention.
     I           ~~~A number of federal, state, and local agencies proved helpful during
             the course of the study. Discussions with the staff of the South
             Carolina Coastal Council proved particularly useful throughout the project;
    I      ~ ~while the staff of the South Carolina Sea Grant Consortium, and especially
             Mr. Rick DeVoe, provided assistance-and arrangements for the final draft,
    j ~~which had long exceeded its original completion date. The directors of
             these respective agencies, Drs. Wayne Beam and John Armstrong, deserve
    5 ~~special acknowledgement for their foresight and fortitude in addressing
             one of the critical resource problems in South Carolina as well as other
    3       ~~coastal states.
                  Other organizations providing assistance included: the South Carolina
             Department of Parks, Recreation, and Tourism, the U.S. Army Corps of

             Engineers, the City of Myrtle Beach, the Waccamnaw Regional Planning
             Commission, the Beaufort County Planning Department, and the Tax
    j       ~~Assessor's Offices of Beaufort, Georgetown and Horry Counties.  While in
             terms of individual contribution, commendation must be given to Wilhelmina
    5       ~~Keith for her accurate typing and patience during several revisions of
             the report.
     �           ~~~Finally, funding for this study was provided by the South Carolina
             Coastal Council to the State Sea Grant Consortium under Grant-In-Aid
    j       ~~Award Contract NA-79-AA-D-CZ126.

            I                           ~~~~~~~~~TABLE OF CONTENTS

                      j                                                     ~~~~~~~~~~~~~~~~~~~Page

                TITLE PAGE .i.............

                EXECUTIVE SUMM4ARY .                                        .....i     ......

     j       ~~~ACKNOWLEDGEMENTS....................... xi

                LIST OF TABLES.                                              .......................XV

     I        ~~~LIST OF FIGURES ..                                       .....................xvii

    .1       ~~CHAPTER

                    I. INTRODUCTION .1..........

      5          ~~~II.  COASTAL PROCESSES.................                  4

                              Geomorphic Zones of the South Carolina Coast  .   4
                              Coastal Processes.                                ...............7
         I                 ~~~~~~~Tidal Regime................                7
                                Wave Climate.                                   ................12
                                 Longshore Sediment Transport.                   ........13
                                Tidal Inlet Processes.                          ............14
                                 Storm Effects.                                  ................16
                                 Sea-Level Rise.                                 ...............16
                                Coastal Processes and Beach Erosion.           .....18

                  III.  ENGINEERING SOLUTIONS.                                ..............25

        j                 ~~~~~~Consideration of Alternatives.               .........27
                                 Beach Nourishment.                              ..............27
                                Seawalls.                                       ..................29
                                 Bulkheads.                                      ..................30
                                 Revetments.                                     .................30
                                 Groins.                                         ...................31
                                Jetties and Inlet Control.                      ..........33
                                   Breakwaters.                                  .................34
                              Selection of Alternatives.                        ...........35

     5          ~~~~IV.    THE MANAGEMENT OF COASTAL DEVELOPMENT.           ......39

                              Inducement to Development.                        ...........41
         3                  ~~~~~~~Private Incentives.                       .............41
                                 Institutional Inducements.                      ..........43
                                   Bridge and Highway Construction Programs  . .43
                                   Shoreline Protection Programs.                .......44

                                   Flood Insurance Programs.                     .........44

    U        ~~~Table of Contents (Cont'd.)                                  xiii

                      5                                                       ~~~~~~~~~~~~~~~~~~~Page

                                  Wastewater Treatment Facility Grants . . .  .46
                                  Small Business Loans.                          ...........46
                                  Economic Development Grants .........47
        I                   ~~~~~~~~Home Mortgage Insurance.                  .........48
                                The Benefit of Development.                      .........48
                                The Cost of Development.                         ..........51
                                The Optimal Use of the Resource.                 ......54
                   V.     PUBLIC POLICY TOWARD EROSION CONTROL.                ......67

                              Federal Policy.                                    ................67
                                The Corps of Engineers ..                         ..........67
                                The Federal Flood Insurance Program .        . .. 68
        I                  ~~~~~~~The Coastal Zone Management Program.        ....69
                                New Directions in Federal Policy.                ......70
                              State Policy.                                      .................72
      .1                  ~~~~~~~Policies Employed by Other Coastal States  . 73
                                Policy in South Carolina.                        ..........74
                              Local Policy.                                      .................77
       I                ~~~~~~~Funding Responsibility.                       ............81
                                  Federal Responsibility.                        ..........81
                                  State Responsibility.                          ...........83
        3                     ~~~~~~~~Local Responsibility.                   ...........86

                  IV.  LEGAL CONSIDERATIONS.                                   ..............89

       3                  ~~~~~~~Authority to Regulate Erosion Control Activities   89
                              Problems Associated with the Control of Beach
                                 Erosion.                                        ......91
                                Non-Structural Solution; and' the Tak'in'g'Issue.  91
                                Engineering Solutions.                           ...........93
                                Ownership of Accreted Land.                      .........95
                              Implementation of Erosion Control Policy . . .  .97
                                 Non-Structural Solutions ..                      .........97
                                Engineering Solutions ..                          ..........98

    j         ~~~VII.  CASE STUDIES.                                         ..................104

                              Case A:  Hunting Island............
                               Beach Morphology ..                              .............107
                                 Long-Term Shoreline Changes.                   ........107
                                 Short-Term Shoreline Changes.                  .......118
                                 Hutiting Island Beach Profiles 1974-1976 . . . 118
        I              -    ~~~~~~~Hunting Island Beach Profiles 1979-1980 .   ..123
                               Engineering Solutions                        ............. 133
                               Benefit-Cost Analyses ..                         ...........138
        I                   ~~~~~~~~Prevention of Property Loss.              ........138
                                 Recreational Benefits.                         ...........140
                                 Project Costs.                                 ...............144
        5                    ~~~~~~~~Summary of Benefits and Costs.           .......144

    3        ~~~Table of Contents (Cont'd.)                                  xiv
                                                                                    Page

       I                 ~~~~~~~Case B:  Hilton Head Island.               ........148
                                Beach Morphology.                              ............148
                                  Long-Term Shoreline Change:  1898-1979      149
        �                   ~~~~~~~Shoreline Changes 1951 to 1973:
                                     Aerial Photographs.                       .........154
                                  Short-Term Changes:  Beach Profiles . . .  157
                                Engineering Solutions.                         .........164
                                  Beach Nourishment.                           ...........167
                                Benefit-Cost Analyses.                         ..........167
                                  Prevention of Property Loss.169
        I                   ~~~~~~~~Recreational Benefit.                  .........174
                                  The Costs of Beach Stabilization  . . . .174
                                  Summary of Benefits and Costs.               .....177

                             Case C: Pawleys Island ...........
                                Beach Morphology.                              ............178
                                  Long-Term Shoreline Changes.                ......178
                                  Short-Term Shoreline Changes.                .....182
                                Alternative Solutions.                         ..........182
                                  No Action.                                   ...............182
        I                   ~~~~~~~~Bulkhead.                              ...............185
                                  Riprap.                                      ................187
                                  Terminal Groin.                              ............187
        3                    ~~~~~~~~Inlet Stabilization.                  ..........189
                                Cost-Benefit Analysis.                         ..........191
                                  Property Loss.                              .............191
                                  Recreational Benefit.                       .........194
                                  The Cost of Alternatives.                    .......194
                                  Summary of Benefits and Costs.               .....196

       I                 ~~~~~~Case D: Myrtle Beach ............
                                Beach Morphology.                              ............200
                                  Long-Term Trends.                           ...........201
        I                   ~~~~~~~~Short-Term Shoreline Changes.          .....204
                               Engineering Solutions.                         ..........211
                                  Beach Nourishment.                           ...........212
                                  Of fshore Breakwater.                        ..........214
        I                  ~~~~~~~Benefit-Cost Analyses.                    ..........216
                                  Prevention of Property Loss.                ......216
                                  Recreational Benefit.                        .........220
                                  The Cost of Erosion Control Measures  .         224
                                  Summary of Benefits and Costs ..             ....225

    5        ~~~VIIIL    CONCLUSIONS AND RECOMMENDATIONS.                  .......232

              APPENDICES ..                                                 ......................236

    �          ~~~A.  Federal Guidelines for Shoreline Erosion/Mitigation
                           Planning.                                         ..................241
    3           ~~~~B.  South Carolina Erosion Control Policies.243

                              LIST OF TABLES

    CHAPTER

    VII.   A- 1.  Data Base:  Hunting Island Shoreline Changes ..... 108

          A- 2.  Hunting Island shoreline changes in meters
                 (1859-1972) ...................... 117

          A- 3.  Average yearly shoreline change in meters, based on
                 25, 50 and 100 year trends on Hunting Island ..... 117

          A- 4.  Historic project costs for beach nourishment at
                Hunting Island .................... 135

          A- S.  Value of property loss on Hunting Island under
                 alternate erosion scenarios .............. 141

          A- 6.  Projected visitation and recreational value occurring
                 for periodic beach nourishment at Punting Island . . . 142

          A- 7.  Costs of beach nourishment at H1unting Island ..... 145

          A- 8.  Summary of costs and benefits of beach nourishment
                 at Hunting Island in present value terms ....... 146

          B- 1.  Beach profiles:  North Hilton Head Island ....... 156

          B- 2.  Beach profiles:  South Hilton Head Island ....... 1S6

          B- 3.  Nourishment costs - Hilton Head Island ........ 167

          B- 4.  Distribution of value on lots - Hilton Head Island
                 by quarters of lot .................. 172

          B- S.  Value of property loss (all areas) on Hilton Head
                 Island by time interval ................ 173

          B- 6.  Projected visitation and recreational value accruing
                 for periodic beach nourishment at Hilton Head Island . 175

          B- 7.  Costs of beach nourishment at Hilton Head Island . . . 176

          B--8.  Summary of costs and benefits of beach nourishment at
                 Hilton Head Island in present dollar values ...... 177a

                    I                                                          ~~~~~~~~~~~~~~~~~~~~xvi

    5              ~~~~~C- 1. Bulkhead cost - Pawleys Island.                           ............187

                      C- 2. Riprap cost - Pawleys Island.                                .............187

    I              ~~~~~C- 3.  Terminal groin cost - Pawleys Island ...........189

                      C- 4. Dredging cost - Pawleys Island.                              ............189, 191

                     C- S.  Distribution of property values at Pawleys Island
                             by lot section.                                             ....................192

    I              ~~~~C- 6.  Projected property loss and present value of property
                              loss resulting from.                                        .................193

    1              ~~~~C- 7.  Projected visitation and recreational value accruing
                             for periodic beach nourishment at Pawleys Island . . . . 195

                     C- 8.  Projected costs and present values of these costs
                             for each of four erosion control alternatives for
                             Pawleys Island.                                           .................... 197, 198
    I              ~~~~C- 9.  Summary of benefits and costs of shoreline protection
                             alternatives at Pawleys Island.                             ............199

                     D- 1.  Beach Profiles at Myrtle Beach, 1878-1973.                  ......203

                     D- 2. Nourishment Cost - Myrtle Beach.                             ...........214

                     D- 3. Breakwater Cost - Myrtle Beach.                              ............214

                     D- 4.  The present value of property benefit accruing from
      I                   ~ ~~~~~erosion control at Myrtle Beach by area and lot
                             section.                                                   .......................219

    3              ~~~~D- 5a. Projected visitation and recreational value accruing
                             for periodic beach nourishment at Myrtle Beach -
                             Scenario I.                                                ......................221

    I              ~~~~D- 5b. Projected visitation and recreational value accruing
                             for periodic beach nourishment at Myrtle Beach -
      3                    ~~~~~~~Scenario I .                                         .....................222

                     D- 6.  Estimated costs of beach nourishment and beach nourish-
      I                    ~~~~~~ment with offshore breakwaters for Myrtle Beach . . . . 224

                     D--7.  Estimated costs and present value of costs for pro-
                             posed 10 and 3.28 mile beach nourishment projects . . . 226

                     D- B.  Estimated costs and present value of costs for pro-
                             posed 10 and 3.28 mile beach nourishment projects
      I                    ~~~~~~~with offshore breakwaters.                           ..............227

                     D- 9.  Summary in present value terms of the benefits and
                             costs of beach nourishment at Myrtle Beach under
      I                  ~ ~~~~~~alternate project, cost, and erosion scenarios.      228

                              LIST OF FIGURES

    CHAPTER

    II.     1. Map of the South Carolina coast showing the four
               major morphologic zones ................ 5

           2.  Variation in wave height, tidal range and areas of ebb-
               tidal deltas along the South Carolina coast .......          8

           3.  Variation in morphology of coastal plain shorelines
              with respect to differences in tidal range ........10

           4.  Morphological model of typical mesotidal barrier
               island shoreline of medium wave energy .........11

           5.  Direction of deep water wave approach along the
               South Carolina coast .................. 13

          6.  Sea level change between 1920 and 1970 compiled from
              tide records at Charleston, SC and Fort Pulaski, GA . . . 18

           7.  Representative beach profiles from each of the four
              morphological zones of South Carolina ......... 20

           8.  A series of beach profiles showing depositional-erosional
              trends at locations representative of each morphologic
              types of the South Carolina coast ............22

    IV.     1.  The marginal benefit and cost accruing from beach usage � 55

    VII. A- 1.  Long-term changes on Hunting Island compiled from
              nautical charts between 1859 and 1979 ......... 109

        A- 2.  Refraction of 4-second waves from the east over the
               1857 bathymetry in the vicinity of Hunting Island
              and St. Helena Sound .................. 111

        A- 3.  Refraction of 4-second waves from the east over the
               1937 bathymetry .................... 112

        A- 4.  Refraction of 4-second waves from the east over the
               1978 bathymetry .................... 114

        A- 5.  Depositional - erosional trends along Hunting Island
              compiled from vertical aerial photographs and
              nautical charts .................... 115

        A- 6.  Superimposed low water shorelines from 1951, 1959
              and 1972 aerial photo sets ............... 116

                                                            xviii

    A- 7.  Location of Hunting Island beach profile stations . . . . 120

    A- 8.  Comparison of beach profiles from selected dates
          between August, 1974 and August, 1976 at station H10I.
          Net change is shown in lower plat ........              .... 121

    A- 9.  Volumetric change in cubic meters per meter of beach
          between survcy dates at Hunting Island orofile stations
          H101, !1102, and 11103 .  . . . . . . . . . . . . . . . . . 122

    A-10.  Comparison of beach profiles from selected dates at
           station !H102 . . . . . . . . . . . . .  . . . . . . . . .  124

    A-l11.  Comparison of beach profiles from selected dates at
           station 11103 . . . . . . . . . . . . . . . . . . . . . . . 125

    A-12.  Comparison of beach profiles from selected lates between
          November, 1979 and July, 1980 at station 111-1. Net
          change is shown in lower plat ............. 126

    A-13.  Volumectric change in cubic meters per meter of beach
           at five HIunting Island profile stations, November, 1979)
          to Jtuly, ]9S . . . . . . . . . . . . . . . . . . . . . . 1

    A-14.  Comparison of beach profiles from selected dates at sta-
           ion !1I-3 .   . . . . . . . . . . . . . . . . . . . . . . . 129

    A-15.  Comparison of beach profiles from selected dates at
           station  tiI-5 ................. ].l3

    A-16.  Comparison of beach profiles from selected dates at
           station 111-6 . . . . . . . . . . . . . . . . . . . . . . .  132

    A-17.  Comparison of beach profiles from selected dates at
           station !HI-7 . . . . . . . . . . . . . . . . . . . . . . . 134

    A-18.  Hunting Island nourishment profile............  137

    A-19.  Location of existing structures on Hunting Island . . . . 13)

    B- 1.  Long-run changes on Hilton Head Island compiled from
          nautical charts between 1898 and 1979 ......... 150

    B- 2.  Refraction of 6-second waves from the southeast over 1979
          bathymetry in the vicinity of Hilton Head Island .... 152

    B- 3.  Refraction of 8-second waves from the cast over 1979
          bathymetry in the vicinity of Hilton !lead Island..... 15.

    B- 4.  Depositional-erosional trends along Hunting Island com-
          piled from vertical aerial photographs..........  155

    B- 4a. Location of Hilton Head beach profile stations, 1974-76 . 157a

    B- S.  Volumetric change in cubic meters of beach between
           survey dates at Hilton Head profile stations ......         158

                                                         xix

    B- 6.  Comparison of beach profiles from selected dates between
          September, 1974 and August, 1976 at station HH2 ...... 159

    B- 7.  Comparison of beach profiles from selected dates at sta-
          tion HH3 .........................161

    B- 8.  Comparison of beach profiles from selected dates at sta-
          tion HH4 .........................163

    B- 9.  Comparison of beach profiles from selected dates at sta-
          tion HH5 .........................165

    B-10. Proposed nourishment - Hilton Head ............ 168

    B-11.  Zones employed for assessing beach property loss . .... 171

    C- 1.  Changes in shoreline position on Pawleys Island based on
          aerial photo surveys from 1939 to 1973 .......... 179

    C- 2.  Geomorphic changes at Midway Inlet since 1950.                181

    C- 3.  Comparison of selected beach profiles between 1974 and
          1976 at Pawleys Island beach profile station PMI ..... 183

    C- 4.  Volumetric change in cubic meters per meter of beach at
          beach profile station PWI ................. 184

    C- S. Proposed bulkhead - Pawleys Island ............ 186

    C- 6.  Proposed riprap profile - Pawleys Island ......... 188

    C- 7.  Proposed terminal groin and position - Pawleys Island.        190

    D- 1.  Depositional-erosional trends along Myrtle Beach com-
          piled from vertical aerial photographs and historical
          charts ..........................202

    D- 2.  Location of Myrtle Beach profile stations, 1974 to 1976. . 205

    D- 3.  Comparison of beach profiles from selected dates between
          September, 1974 and October, 1975 at station OF-1 ...... 206

    D- 4.  Comparison of beach profiles from selected dates between
          August, 1974 and August, 1976 at station MB-1 ....... 207

    D- 5. Comparison of beach profiles from selected dates between
          September, 1974 and October, 1975 at station RC-1 ..... 208

    D- 6.  Comparison of beach profiles from selected dates between
          September, 1974 and October, 1975 at station SP-1 ..... 209

                                                                    xx

    D- 7. Volumetric change in cubic meters per meter of beach between
            survey dates at Myrtle Beach stations OF-1, MB-1, RC-1
           and   SP-1  .   .   .   .   .   .   .   .   .   .   .   .   .   .   .   .   .   .   .   .   .   . ...  210

    D- 8.  Proposed beach nourishment - Myrtle Beach . . . . . . .  213

    D- 9.  Proposed breakwater and position - Myrtle Beach . . . .   215

    D-10.  Zones employed for assessing property loss .   . . . . . 217

                                                CHAPTER I

            3                                 ~~~~~~~~~~I NTRODUCT ION

     3             ~~~~Coastal  erosion is not a new phenome-nonhaving occurred historic-

               ally due to changes in coastal processes. These processes have both

    I         ~~~created the present barrier island chain along the Atlantic and Gulf

    3         ~~~coasts as well as significantly changed their formation over time.  Al-

               though short-term changes are often erratic, the dominant trend in

    3         ~~~recent geologic times has been one of gradual long-term erosion.

                    Despite the long-term nature of this erosional trend, related pro-

    I         ~~~perty loss has increased significantly in recent years due primarily to

    3         ~~~the rapid development of beach areas that has occurred since the end of

               World War II. This convergence of forces has led to a classic conflict

    3         ~~~of man against nature, i.e., man's desire for stable land-use patterns

               versus the dynamic nature of the coastal system.

     I              ~~~~In response to this conflict, the public as well as state and

               federal officials have expressed concern from which considerable atten-

               tion has been given to methods of more effectively managing coastal

    3          ~~~resources.  The issue of coastal erosion is addressed in the Coastal

               Zone Management Act of 1972 and more specifically in the 1976 Amendment

    3          ~~~to that act which states that:

                         The management program for each coastal state include
       I                   ~ ~~~~~a planning process for A)  assessing the effect of
                         shoreline erosion (however caused), and B) studying
      3                  ~~~~~and evaluating ways to control, or lessen the impact
                         of, such erosion, and to restore areas adversely
      3                  ~~~~~affected by such erosion.
                                                      (Federal Register 923.25).

                     *                                                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~2

              The program must include a method for assessing the effects of shoreline

    I        ~~erosion and of techniques for controlling this erosion.  It must also

              identify and describe "enforceable policies, legal authorities, and

              funding techniques" to be used in erosion management. (Section 305

    5         ~~~(c)(2).

                    It is for these reasons that the present study was undertaken with

    I        ~~emphasis given to the particular problems affecting the South Carolina

               coast. In the report that follows, issues affecting coastal erosion

              both from a physical and management perspective are addressed. Specific
    I         ~~~issues examined include:

                         1) the coastal processes influencing beach formation
        3                    ~~~~~~with particular emphasis given to the South Carolina
                             coast,
                         2) the state-of-the-art in terms of engineering solu-

                             tions for shoreline protection and the technical
                             and economic feasibility of applying these mea-

                             sures,
                         3) the pertinent public policies affecting coastal
       3                    ~~~~~~development and erosion control at the federal,
                             state, and local level,
      3                 ~~~~~4)  a consideration of appropriate public manage-
                             ment responsibility and options including
                             control and funding provisions, and

                         5) the legal considerations associated with
                             oceanfront properties and influencing alternate

                             management strategies.
    3         ~~~Also introduced is a framework for assessing the public benefit of alter-

               nate erosion control techniques. The framework is applied, in turn, to

    3         ~~~four sites along the South Carolina coast reflecting different physical

               and development characteristics. These sights include:

                      1                                                                ~~~~~~~~~~~~~~~~~~~~~~~~~3

                           1) Myrtle Beach,
       3                   ~~~~~2)  Pawleys Island,
                           3) Hunting Island, and
       3                   ~~~~~4)  Hilton Head.

               Finally, based upon the findings of this study, policy recommendations

    5          ~~are suggested to provide for effective long and short-term management

               of the state's coastal resources.

                                              CHAPTER II

           I                               ~~~~~~~~~~COASTAL PROCESSES

     3             ~~~~Before designing erosion abatement strategies, it is appropriate

               first to consider the factors and processes affecting coastal geomorpho-

    I          ~~~logy.  The following section is based largely on previous and ongoing

    3         ~~~studies of beach erosion, barrier island morphology, and sediment

               transport along South Carolina barrier islands and adjacent tidal inlets.

    3         ~~~The majority of these discussions are based on work conducted by the

               Coastal Research Division of the Department of Geology at the University

    I         ~~~of South Carolina.

       3                    ~~~~~~Geomorphic Zones of the South Carolina Coast

                    The South Carolina coast is transitional between the wave-dominated

    3         ~~~North Carolina and the mostly tide-dominated Georgia coast.  Within South

               Carolina borders, the coast can be divided into four morphologic zones.

    U         ~~~The arcuate strand portion of South Carolina stretches from the border

               of North Carolina to Winyah Bay (Fig. 1). Here, beaches are mainland

               connected and salt marsh-tidal creek systems are absent or poorly develop-

    U         ~~~ed.  The shoreline is gently curving, convex seaward, and breached by

               only one major inlet (Little River Inlet) at the north end. The number

    3         ~~~of inlets increases to the south toward Winyah Bay with salt marsh-tidal

               drainage associated with inlet systems encompassing greater acreage.

               Beaches along the arcuate strand may be backed by a well-developed dune
    3         ~~~system up to 3 meters in relief, but, at many locations, the dunes have

               been leveled for real estate development.

     3             ~~~~The shoreline of the arcuate strand fringes the seaward side of

               Pleistocene beach deposits known as the Myrtle Beach Formation. The pre-

                ~i  t  r                   ,   ~~~MYRTLE BEACH
        1\, i
                   1                          N

                                 3  \zWINYAH BAY

                            5;      N L'fCAPE ROMAIN

               CHiARLESTON       BULL  ISLAND  -Arcuate Strand
                       3  "S .>' MORRIS ISLAND   'Cuspate Delta
                       EDINGSVILLE     -- EBeach-Ridge Barrier
                       BEACBEACH              :Transgressive
               1-BA Y POINT                             Barrier
                                                0 o50
       I'._ '-HILTON HEAD ISLAND                            km
                                           --BEACH PROFILE STATION

    Figure 1. Map of the South Carolina coast showing the
      four major morphologic zones (after Brown, 1977).

                    3                                                         ~~~~~~~~~~~~~~~~~~~~~~~~6

    3         ~~sent day shoreline is parallel and subparallel to Pleistocene beach

              ridges, the erosion of which may be a local source of sand for modern

    I         ~~beaches.

                   The cuspate delta section of South Carolina extends approximately

              30 km from Winyah Bay to Bull Bay. The Santee River Delta complex is

    3         ~~the largest on the east coast and consists of three morphologic compo-

              nents. The first, Cape Romain, is termed a cuspate foreland. The

    3         ~~Cape is thought to have formed from deltaic deposits reworked by waves.

              The second component is a beach-barrier system known as Raccoon Key

              while the third component consists of distributary mouth bar sand and
    3         ~~mud flats associated with the mouth of the present Santee River.  Prior

              to damming of the Santee River and diversion of part of its flow into

    3         ~~the Cooper River in 1942, the delta complex was in a stable or construc-

              tional stage (Aburawi, 1972). Since that time, the cuspate delta area

    I         ~~has been in a destructive period due to the loss of sediment from the

    3         ~~river bed.  Numerous truncated beach ridges, washover terraces and the

              rapidly retreating shorelines of Cape Romain and Raccoon Key are indi-

    3         ~~cative of this trend.

                   The South Carolina coast between Bull Bay and the Georgia border

    3         ~~~(160 kmn) is comprised of barrier islands separated by tidal inlets and

    3         ~~larger estuarine systems such as St. Helena Sound and Port Royal Sound.

              Barrier islands can be subdivided into two distinct types. Beach

    *         ~~ridge barriers are formed from sets of parallel beach ridges that have

              prograded seaward over time. The majority of barriers along the coast

    I         ~~are the beach ridge type, but several of the islands can be classified

    3         ~~as erosional or transgressive (Fig. 1).  These islands characteristi-

              cally have low relief and are composed of a thin veneer of sand activity

                    1                                                         ~~~~~~~~~~~~~~~~~~~~~~~~~7

    3        ~~retreating landward over salt-marsh deposits that are extensively develop-

              ed behind most South Carolina barrier islands. The beaches are backed

    I        ~~by extensive washover terraces with limited or no dune development.

    3        ~~Examples of transgressive barriers on the South Carolina coast include

             Morris Island, Edingsville Beach,and Bay Point Island. Beach ridge type

    3        ~~barriers may be converted to transgressive barriers by continued long-

              term erosion. Evidence for this type of evolution is found in historical

    I        ~~nautical charts indicating beach ridges on Morris Island and Edingsville

    3        ~~Beach in the 18th century.

                                          Coastal Processes

     3            ~~~~Coastal geomorphology and trends of erosion and transport and depo-

              sition of sediments along the South Carolina shoreline are controlled by

    3        ~~several factors and dynamic processes.  Among the most important factors

    3        ~~are tidal regime and wave regime (Hayes, 1979). 1In early work on coastal

             morphology, Price (1955) discussed the importance of the type and amount

    3        ~~of hydrologic energy expended in the evaluation of any shoreline.  The

             predominent scientific opinion on this matter attributes such occurrences

    I        ~~as longshore sediment transport effects of inlets, sediment supply, storms,

    3        ~~and short-term sea-level changes to tidal regime more often than wave

              climate and other processes. Earlier findings along the South Carolina

    3        ~~coast reinforce this opinion (Hayes, 1979).  Consideration of tidal

              regime is particularly important to the study area as spring tidal range

    3        ~~varies from approximately 1.3 m at the North Carolina - South Carolina

              border to 2.7 m at the South Carolina - Georgia border (Fig. 2).

              Tidal Regime

     3            ~~~~Davies (1964) suggested a general shoreline classification scheme

             based on tidal range. Microtidal coasts include areas where tides range

                                                                    8

              _*~ ~EBB - TIDAL DELTAS
                          SOUTH  CAROLN OS

                                         EBB TIDAL DELTA AREA
         TIDE                                                               WAVE
        RANGE                                                                HEIGHT
        280                                                                  ,  80
               1  220-                 - WAVE  HEIGHT '                           (
                    220 ~~~~~~~~~.......  IA
    (CM)    -         .      . ..                                   "           -  (CM)
                   160--~ ~~~~~~~~~ni**                            40
        (CM) 160- .,_,_,_,_,_ ,_ .^'" . TIDE RANGE-e'-

          10t....................TDRAG
        100                                                                    20
                                                                 After Brown, 1976

    Figure 2.  Variation in wave height, tidal range, and areas of ebb-tidal
      deltas along the South Carolina coast (after Brown, 1976).

          *                                                         ~~~~~~~~~~~~~~~~~~~~~~~~~9

    from 0 to 2 meters, mesotidal coasts where tidal range is from 2 to 4 me-

    ters and macrotidal coasts of tidal range greater than 4 meters. The

    relative amounts of tidal energy to wave energy vary systematically

    among the three coastal classes.  In areas of moderate to high wave energy

    and small tidal range (microtidal), the shoreline is dominated by waves

    (Hayes, 1979).  Macrotidal areas are dominated by tide-related processes.

    Mesotidal areas show the effects of both waves and tides and may be

    termed mixed energy coasts (Hayes, 1965).

         The main reason for emphasis on tidal regime is the fact that the

    wave climate is variable in many coastal areas; whereas at many locations

    tidal energy is relatively constant, even considering neap-tide to

    spring-tide variations. Price (1955) noted, however, that areas of small

    tidal range may be considered tide-dominated if wave energy is low.

         Along coastal plain shorelines of moderate wave energy (such as the

    South Carolina shoreline), morphology varies systematically with tidal

    range (Hayes, 1975).  On microtidal coasts, barrier island development

    and river deltas may be the most prominent geomorphic features.   Typi-

    cally, tidal deltas and inlets are poorly developed, and tidal flat and

    salt marsh deposits are absent or of only local importance (Fig. 3).

    Tidal deltas are best developed and inlets most frequent on mesotidal

    coasts.  Barrier islands along such coasts tend to be poorly developed

    or absent in areas included in the upper portion of the mesotidal classi-

    fication (3-4 m); whereas tidal flats and salt marshes are of increased

    importance.  In macrotidal areas (embayments), tidal flats and salt

    marshes commonly extend over broad areas. Sand deposits are in the form

    of offshore linear sand shoals or tidal current ridges.

         The South Carolina coast displays characteristics of shorelines transi-

    tional between microtidal and mesotidal and of a true mesotidal shoreline.

                                                                             10

                          17 RIVFR BARRIER TIDAL LSINNEARDILT TIDAL JSALT
                            DELTA ISLAND DELTAS  FS   INLETS
               3~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

                          6-

                        O " -

                          2                                               Ei:lii:iiiil   ~~::?~?:iii
    U~~~~~

                                                                      E

                  Figure 3. Variation is morphology of coastal plain shore-
                    lines with respect to differences in tidal range (after
                    Hayes, 1975).

     ,-,                             X                 ': ": WAVES

           NV

      MESOTIDAL
                                        ,,.,, 'i!i'   :  010km
      CP SHORELINE                                         -
     BETWEEN MAJOR
           RIVERS

    Figure 4. Morphological model of a typical mesotidal barrier island
     shoreline of medium wave energy.

                                                                   12

    The arcuate strand falls within the microtidal classification;

    although it does not have the typical long, linear barriers of microtidal

    areas, minimal development of tidal inlets, tidal flats and salt marshes

    are present.  The barrier island section of South Carolina, and, in

    particular, the southern part of the coast is typically mesotidal, dis-

    3playing the increased effects of tidal processes. South Carolina barriers

    have a short, stunted appearance and are separated by numerous inlets

     (Fig. 4). Shoal morphology associated with inlets within mesotidal area

    and in transitional areas between microtidal and mesotidal is signifi-

     cantly different. Mesotidal inlets (such as Fripp Inlet) are ebb-dominated

    due to extensive salt marsh development (Nummedal et al., 1977; Zarillo,

     1979) and have large ebb-tidal deltas. Microtidal and transitional

    inlets (such as Little River Inlet and Murrells Inlet) where salt marshes

    are poorly developed tend to be more flood dominated.  Flood tidal deltas

     and sand bodies therefore tend to be found behind and within the inlet

    throat.  Such morphologic variations affect the efficiency of sand by-

    passing between barrier islands.

    Wave Climate

         Wave energy available in the nearshore zone varies systematically and

    inversely with tidal range along the southeast coast (Fig. 2; Nummedal

    et al., 1977).  Mean annual wave heights decrease from a maximum of 1.2

    meters along the wave-dominated North Carolina coast to a minimum of

    0.1 meters in central Georgia.

         Direction of deep water wave approach  along with wind-velocity

    varies seasonally (Fig. 5). During the summer months wave energy flux

    is greatest from the southwest and south; whereas  during fall and win-

    ter, wave energy flux from the northeast and east becomes increasingly

    important.  Because of the orientation of South Carolina's shoreline,

                                                  13

         |.~ W~I~'ND ROSES

                U-*rANN U   L        su

                /  .    .

    wave energy flux in the Charleston SSMO data square
    (after Nummedal et al., 1977).
    (after Nummedal at al., 1977).

                                                                  14

    deep-water waves generated in northeasterly to southerly sectors are

    most important.

         Waves generated by storm winds are important to short-term beach

    erosion trends.  The most frequent storm waves approach from the north-

    east and east, generated by passing extratropical storms. In a wave

    refraction study (Fico, 1977), hypothetical storm waves approaching

    from the east at a 10-second period wave orthogonals (wave energy) tend

    to diverge along the arcuate strand and converge in certain areas south

    of North Inlet such as the Price - Capers Dewees Inlet vicinity and
                2
    Cape Romain.   Refraction analysis of hypothetical waves from the south

    and southeast generated by tropical storms indicates increased concen-

    tration of wave energy along the arcuate strand compared with

    extratropical storm conditions.

    Longshore Sediment Transport

         An important process that affects the sediment budget of South

    Carolina's beaches and barrier islands is the longshore transport of sand.

    In South Carolina, longshore currents that transport sand are generated

    by waves striking the shoreline at an oblique angle, by prevailing winds,

    or a combination of both. Longshore currents generated by waves vary in

    speed and direction depending on wave height, wave period and wave angle.

    Waves most effective in generating longshore currents are high angle,

    steep, low period wind waves generated locally. Longshore currents in

    combination with wave forces that erode and suspend sand from the beach

    and shoreface may move large volumes of sand along the shoreline.

         Rates of sediment transport have been estimated at several locations

    in South Carolina.  Finley (1976) and Nummedal and Humphries (1977) esti-

    mated yearly longshore transport rates for Debidue and North Islands from

    wave energy flux calculations based on seasonal wave process measurements.

    The net transport rate of sand along Debidue was directed southward and

    estimated to vary between 150,000 to 500,000 tons per year depending on

    the frequency of northerly and northeasterly winds. Kana (1976) esti-

    mated yearly longshore sand transport on Capers Island and the

    south-facing beach of Bull Island from wave energy flux and measurements

    of suspended sediment load and longshore current velocity. Estimated

    transport rates ranged from 90,000 to 300,000 metric tons per year, all

    directed to the south.

         Knoth and Nummedal (1977) estimated longshore transport on the

    east-facing beach of Bull Island from the dispersal of dyed tracer sand

    in addition to estimates from wave energy flux. Here, net transport is

    directed north and on the order of 90,000 to 230,000 metric tons of sand

    per year. Net sand transport on North Island is also directed north,

    probably due to local wave refraction patterns around the ebb-tidal

    delta associated with adjacent North Inlet.

         Longshore sediment transport studies conducted in South Carolina

    are localized and subject to significant error. Sediment transport rates

    estimated thus far are similar among several locations, and, if this

    -cttern holds, transport in other sections of South Carolina will be on

    the order of 105 metric tons per year, directed predominantly to the

    south. Local direction reversals may occur on the downdrift sides of

    inlets because of wave refraction around inlet-associated shoals. This

    effect may be the cause of the downdrift offset of many of the mesotidal

    barriers in South Carolina (such as Kiawah Island and Fripp Island).

    Tidal Inlet Processes

         On the South Carolina coast, inlets and associated tidal deposits

    are an integral part of barrier island systems. As previously described,

    mesotidal shorelines are breached by numerous inlets that have large

                                                                   16

    ebb-tidal deltas and in some cases well-developed flood tidal deposits.

    Studies of barrier islands in several areas (Moslow and Heron, 1978;

    Hayes, 1979) indicate that tidal-inlet shoals volumetrically may con-

    tain 30 to 60 percent of the sediments deposited in nearby barrier

    islands. In order to maintain the sand budget of downdrift beaches

    some of this sediment must eventually bypass the inlet system. The

    mechanism of sand bypassing varies with inlet type. At wave domi-

    nated, microtidal inlets where ebb-tidal deltas are poorly developed

    and donot extend far offshore, sand may easily bypass the inlet along
    the outer shoals or outer bar of the inlet.

         Sand bypassing at more tide-dominated transitional and mesotidal

    inlets is more complex. Ebb-tidal deposits may extend for several

    kilometers offshore, and updrift and downdrift shoals are separated

    by a large ebb-dominated tidal channel.  Here sand can only be by-

    passed by a channel reorientation or abandonment process. Generally,

    sand is collected or trapped on the updrift side of an inlet, forcing

    the inlet channel to migrate laterally in the downdrift direction un-

    til the configuration becomes unstable.  A new channel may cut through

    the updrift shoals and, in effect, transfer the shoals to the down-

    drift side. The bypassed sediment then may migrate landward under

    the influence of wave refracting around inlet shoals and be added to

    the littoral system of the downdrift beach or barrier.  This migration is

    responsible in nart for the downdrift offset of barrier islands and is

    the most common method of sand bypassing found along the barrier island

    section of South Carolina. As a consequence, portions of barrier islands

    adjacent to inlets are typically unstable,  and large  and  rapid

    change may occur depending on inlet morphology. The distal

                    I                                                          ~~~~~~~~~~~~~~~~~~~~~~17

    I        ~~ends of barrier islands in South Carolina are thus subject to periodic

             rapid deposition, ridge and runnel activity and to episodes of rapid

    I   ~~~erosion depending on shifts in tidal channel position.

    3        ~~Storm Effects

                  The effect of storms has been mentioned in the section on wave

             climate but deserves separate mention because of accelerated rates of

              erosion that occur during storm conditions. One of the main aspects of

    I        ~~storms along the coast is storm surge, which can be described as the rise

    3        ~~above normal water level.  Storm surge results from a combination of

             wind stress and reduced atmospheric pressure.

                   Storm surges can cause unusually high tides which when combined with

             high waves produced from strong winds may cause extreme beach erosion in

    I        ~~a short period of time.  Hurricanes are easily the most destructive

    3        ~~storms to strike the South Carolina coast, but their low rate of occur-

             rence makes them less significant in long-term shoreline change than

    5        ~~more frequent extratropical storms approaching from the northeast.

             Sea-Level Rise

     I            ~~~A factor that must be considered in any study of beach erosion is

    3        ~~the effect of sea level change.  A continuous rise in sea level will

              result in a long-term erosional trend and landward barrier retreat.

    3        ~~From 3,000 to approximately 2,000 years B.P., sea level along the east

              coast of North America rose at a rate of about one foot per century

    I        ~~(Kraft, 197.1).  At present, the long-term rate of sea level rise may be

    3        ~~on the order of a half foot per century, although rates have accelerated

              along the east coast (Fig. 6) and may be contributing to recent trends

    3        ~~of beach erosion.  Accelerated sea level rise is probably only a short-

              term fluctuation, yet the destabilizing effect on shorelines may be sig-

    ~~~ifiat

                                    TIME (years)
                        19.20 1930 1940 1950 1960 1970
                         '20...

                         -i5
    I~~~~~~~~~

                           CHARLTIESTN (years

                                        ORT PULASKI, GA.

                  Figure 6. Sea level change between 1920 and 1970
                    compiled from tide records at Charleston, Si CA
                    and Fort Pulaski,, Ga.

                   At some locations, the effect of sea-level rise may be more than

              offset by abundant sediment supply. A notable example of this is the

              northeast end of Kiawah Island, South Carolina where several sets of

    U         ~~new beach ridges have developed over the past fifty years.

              Coastal Processes and Beach Erosion

     I            ~~~~The major factors and processes that are important in controlling

              beach erosion trends have been discussed individually. The final re-

              sult produced by combinations of these parameters are depositional-

    3         ~~erosional trends displayed by South Carolina beaches.  In addition to

              net erosion or accretion at any particular location, the effect of

    5         ~~coastal processes can be clearly seen in the overall morphology of the

              beach. Beach morphology to a certain degree reflects recent history

              of sedimentation. Overall, South Carolina beaches are wider and lower

              compared with other beaches along the eastern United States. This is

              a function of the large tidal range and finer grain size of beach

              sands along the South Carolina coast. Within each morphologic shore-

              line type, beaches vary significantly. Beach morphology along the

    1         ~~arcuate strand region is characterized by a relatively flat beach face

    3         ~~that may become concave during erosional cycles (Fig. 7).  Erosional

              beaches of the transgressive barrier and cuspate delta sections of

    3         ~~South Carolina generally have steeper beach faces and are narrower than

              other South Carolina beaches. These characteristics are, in part, a

    I         ~~function of coarser-grained sands that are available to the littoral

    3         ~~system in these areas.  Profiles of beach-ridge barriers in a construc-

                                                                                              20

                              4.o1j                     LCB1

                               0.001                   10/6/75

                           o                   LHTS

                                                                      WL
                                  ARCUATE STRAND
    I                        ~~~~~~~~~~~.8.00
                                000    20.00    40.00   60.00   80.00
                                               DISTANCE IM)

                               I  0-B.             CR03
                                                  1230
                                                 20/7/75
      1                          0.001   ~~~~~~~~~~~~WAIS"VEP  LH-TS

                                    .4.0               R~~~~~~ACE  WI.

                              00CUSPATE DELTA
                                 0.00    2      4.00   A0.00    60 .0   80 00

                               50oo C.                                         FBO3
                                                                           1213
                                                                          8/8/76
                            1 0.00-f'`
                                Z          L~~~HTS
                                                           RIDGE
                                                 ------------------------- Ae.,_~~_~,L W
                                                                               "--�--�--�----�--�--�---

                                   BEACH-RIDGE BARRIER
                              -8.OC,      .r0 .60
                                 0.00    20.00   40.00    60.00   8600 Iad 00   120.00   1o.0 o   180.00
                                                                DISTANCE (M)

                               I  '0 D.                EBOl
                                                     1329
                                                    6/6/75
                               0.00-

                                   TRANSGRESSIVE BARRIER
                               .8.00
                                  0.00    20.00   40.00    60.00

                            Figure 7.  Representative beach profiles from each of the
                               four morphologic zones of South Carolina (WL = water line;
                               LHTS  = last  high  tide  swash).

                                                                             21

             tional cycle are wide and have a flat beach face across which distinct

             sand ridges frequently migrate, giving the beach a ridge and runnel type

             of morphology. A series of computer-plotted profiles at one location

    3        ~~from each of South Carolina's four beach types show the variation in

             beach morphology over a two-year period between 1974 and 1976 (Fig. 8).

             Short-term volumetric fluctuation in all four beach types are large and

             maybe, in part, seasonal or storm related, but net changes may be small.

             The most prominent morphologic changes and greatest loss of beach sand

    3        ~~and shoreline retreat took place on the cuspate delta and transgressive

             barrier type beaches. These changes can be seen clearly from the shore-

    I        ~~ward retreating dune line and subdued dune relief.

     5            ~~~In general, depositional trends are likely to occur at the dowrndrift

             end of a barrier island which, in South Carolina, is usually the south

             end. This trend may be occasionally reversed when large volumes of sand

             are discussed under tidal inlet processes. At this time, the updrift end

    I        ~~of the adjacent downdrift barrier may undergo a strong depositional

    3        ~~episode as the bypassed sediment is transported onshore by wave action.

             As a consequence of the inlet bypassing process., lateral migration of in-

    3        ~~lets, and wave refraction patterns that change with inlet shoal

             morphology, beaches adjacent to most inlets are typically unstable and

    I        ~~subject to rapid short-term fluctuations.

     3            ~~~Depositional-erosional trends during the recent past and present

             along any particular section of South Carolina's coast depend on a combi-

    3        ~~nation of the various processes and factors discussed above.  Along the

             arcuate strand, wave climate, sediment source and the presence of only

    I        ~~a few inlets combine to result in a long-term relatively stable trend.

                MYRTLE BEACH                           HILTON HEAD

      o / DUNE

                       \,9                    <_            MIGR~~~~~~ATING RIDGES

     -8 AUAETRAN                             BEACH-RIDGE BARRIER

               CAPE ROMAIN                        EDINGSVILLE BEACH
    LU

      0 WASHOVER TERRACE
                        :-B~-EACH FACE

        CUSPATE DELTA                       TRANSGRESSIVE BARRIER
      -8---
       o        40        80        120   0         40        80        120

                                 DISTANCE (M)

       Figure 8. A series of beach profiles showing depositional-erosional trends
         at locations representative of each of the morphologic types of the South
        Carolina coast.

                    *                                                           ~~~~~~~~~~~~~~~~~~~~23

    I        ~~Exceptions to this trend are in the vincinity of Little River Inlet and

    3        ~~Murrells Inlet.

                   South of the arcuate strand, where inlets are more closely spaced,

    5        ~~abrupt and large changes in shoreline position are superimposed on longer-

             term trends. For instance, rapid and significant changes in the

    I        ~~morphology and close spacing of Price, Dewees and Capers Inlets have re-

    I        ~~sulted in abrupt shifts in shoreline position at certain locations on

             Bull, Capers, and Dewees Islands and the north end of the Isle of Palms.

    3        ~~This influence encourages rapid erosional or accretional episodes adja-

             cent to the inlets superimposing longer term erosional trends on Bull,

    I        ~~Capers, and Dewees Islands and stable or accretional trends on the Isle

    *        ~~of Palms.

                  Additional factors that may affect shoreline stability are man-made

    3        ~~structures and changes.  Many man-made alterations such as construction

             of groins, beach nourishment and seawalls may not have long-term, perma-

    5        ~~nent influence on coastal processes, but may slow erosion rates

             sufficiently to be cost-effective. Larger scale projects can alter the

             nature of shoreline processes permanently. Already mentioned are changes

    3        ~~along the Santee Delta section caused by trapping of coarse-grained sedi-

             ments up-river. Not yet discussed are possible effects of jetty

    I        ~~construction to stabilize Charleston Harbor Entrance.  Some evidence

             exists which suggests that accelerated depositional trends on Sullivans

    I        ~~Island and-erosional trends on Morris Island are related directly to

    3        ~~construction of the massive jetties and to changes in shoal morphology

             after completion of the jetties (FitzGerald, et al., 1979).

     3            ~~~When considering shore erosion management options in South Carolina,

             all processes and factors discussed above must be considered. The shore-

                    1                                                        ~~~~~~~~~~~~~~~~~~~24

             line of South Carolina is generally transitional between wave-dominated

    3       ~~and tide-dominated types found elsewhere along the East Coast of the

            United States. Therefore, in addition to considering how other states

    I ~~have approached erosion control, it is necessary to develop an erosion

    3 ~~management program particularly suited to the shoreline characteristics

             in South Carolina.

                  Discussed later in the report are four individual examples of bar-

             riers and beaches typically found in South Carolina. Coastal processes

    I       ~~and factors such as sediment source combine in a different manner within

             each area to give rise to a different set of shoreline erosion problems

             in each case. In addition, the amount of residential and commercial

    3       ~~development varies among the examples adding another dimension to beach

             erosion problems. Hilton Head Island is a resort area that, has recent-

    I       ~~ly undergone rapid development.  Erosion rates here are-not great,

    5       ~~but serious problems have arisen because the island's most erosional

             areas coincide with the more highly developed sections of shoreline.

    I       ~~Hunting Island is presently part of the State Park system and has a
             long history of erosion. Until the present, the beach has been main-

    I       ~~tained artificially by repeated -nourishment projects.  Pawleys Island

             at the south end of the arcuate strand is largely residential; whereas

             Myrtle Beach, at the heart of the arcuate strand, supports a large

    3       ~~tourist industry.  Existing data concerning depositional-erosional his-

             tory and coastal processes affecting each of these areas are outlined

    I       ~~below in case studies pertaining to each of these areas.

                                      REFERENCES                           24a

    Aburawi, R.M., 1972, Sedimentary facies of the Holocene Santee Delta:
         Unpub. M.S. thesis, Univ. of South Carolina, Columbia, S. C., 96p.

    Brown, P.J., 1977, Variations in South Carolina coastal morphology:
         in Nummedal, D. (ed.), Beaches and Barriers on the Central South
         Carolina Coast, Dept. of Geology, Univ. of South Carolina, p. 11-24.

    Davies, J.L., 1964, A morphologic approach to world shorelines: Zeit
         fur Geomorph. Bd. 8, s. 27-42.

    Fico, C., 1977, Wave refraction on the South Carolina coast: in Nummedal
         D. (ed.), Beaches and Barriers on the Central South Carolina Coast,
         Dept. of Geology, Univ. of South Carolina, p. 1-4.

    Finley, R.J., 1976, Hydraulics and dynamics, North Inlet, South Carolina,
         1974-75: Coastal Eng. Res. Center, U.S. Army Corps of Engrs., GITI
         Rept. No. 10, 188p.

    FitzGerald, D.M., Fico, C. and Hayes, M. 0., 1979, Effects of the Charles-
         ton Harbor, S.C. jetty construction on local accretion and erosion:
         Coastal Structures '79, WPCO Div. of ASCE, Alexandria, Virginia,
         p. 641-664.

    Hayes, M. O., 1979, Barrier island morphology as a function of tidal
         and wave regime: in Leatherman, S.P. (ed.), Barrier Islands, Academic
         Press, p. 1-27.

    Hayes, M. O., 1975, Morphology of sand accumulations in estuaries: in
         Estuarine Research, Cronin, L. E. (ed.), v. 2, Academic Press, New
         York, p. 3-22.

    Hayes, M. O., 1965, Sedimentation on a semi-arid, wave-dominated coast
         (South Texas); with emphasis on hurricane effects: Ph.D. diss.,
         Univ. of Texas, 350p.

    Tera, T.W., 1976, Sediment transport rates and littoral processes near
         Price Inlet, S.C.: in Hayes, M. O. and Kana, T.W., (eds.), Terri-
         genous Clastic Depositional Environments, Tech. Rept. 11-CRD, Dept.
         of Geology, Univ. of South Carolina, p. II-158 - II-171.

    Knoth, J.S. and Nummedal, D., 1977, Longshore sediment transport using
         fluorescent tracer: Coastal Sediments '77, Proc. 5th Symp., WPCO
         Div. oi ASCE, Charleston, S. C., p. 543-562.

    Kraft, J.C., 1971, Sedimentary facies patterns and geologic history of
         a Holocene marine transgression: Geol. Soc. Amer. Bull., v. 82,
         p. 2131-2158.

    Moslow, T.F. and Heron, D.S., Jr., 1979, Quaternary evolution of Core
         Banks, North Carolina: Cape Lookout to New Drum Inlet: in Leather-
         man, S.P. (ed.), Barrier Islands, Academic Press, New York, p.
         211-236.

    Nummedal, D. and Humphries, S.M., 1977, Hydraulics and dynamics of
         North Inlet, South Carolina, 1975-76: Coastal Eng. Res. Center,
         U.S. Army Corps of Engrs., GITI Rept. No. 16, 215p.

                                                                        24b

    Nummedal, D. et al., 1977, Tidal inlet variability - Cape Hatteras to
         Cape Canaveral: Coastal Sediments '77, Proc. 5th Symp., WPCO Div.
         of ASCE, Charleston, S.C., p. 543-562.

    Zarillo, G.A., 1979, Interrelation between sediment transport and hydro-
         dynamics in a salt marsh estuary: Ph.D. diss., Univ of Georgia, 219p.

            U                               ~~~~~~~~~~CHAPTER III

           I                            ~~~~~~~~~ENGINEERING SOLUTIONS

                   There are several approaches for treating or coping with shoreline

              erosion. Increasingly, attention is being given to approaches allowing

    I        ~~~nature to take its course and the relocation of endangered property, utili-

              ties and facilities away from the eroded or threatened areas. Often,

    I        ~~this concept has been advocated by individuals who feel that the coast should

             remain (or return) to an undeveloped state. Still more extreme is the-notion

              that we should do nothing and let the endangered property be destroyed

              (Pilkey and Kaufman, 1980). Institutional measures have been developed and

              implemented in some locations to accomplish the objectives of these two

    I        ~~approaches.

                   From a long-term perspective, the concept of design with naturere-

              quiring property owners to assume the risk associated with development

              in coastal areas may offer promise. In the short-term, however, these

              approaches offer little satisfaction for the developed, high-use areas

    3        ~~of South Carolina coast.  For these areas a more explicit program of con-

              trol is needed including a mix of structural and nonstructural solutions.

    I        ~~Prudent engineering in the coastal area for erosion control need not re-

    j        ~~sist the forces of the ocean but should instead work with these forces

              to stabilize the coastline. Unfortunately, structures have not always

    3        ~~been so designed and, in such cases, have met with little success.

             Several very successful projects which worked with ocean forces were

    I        ~~documented by O'Brien and Johnson (1980).

     3            ~~~~It is indeed intriguing to travel along the South Carolina coastline

                    U                                                          ~~~~~~~~~~~~~~~~~~~~~~26

    I         ~~~and notice that some coastal structures are successful in certain loca-

              tions and not in others. In many instances, the structures are very

              much the same, so it is the environment in which they are located that

    3         ~~~controls their degree of success.  If these structures are designed to

               work with the natural forces instead of in opposition to them, the

    3         ~~~solutions will work; otherwise, they will only be another testament

               for the do nothing alternative.

                    In this section, several engineering alternatives are presented for

    3         ~~addressing shoreline erosion.  At the outset it is recognized that all

               structural and nonstructural solutions for shoreline protection will be

    3         ~~~expensive, albeit in some cases, economical, relative to the property

              being protected. In the case of low cost alternatives, much research and

               development has taken place in the past several years. Unfortunately,

    3         ~~~little success has been achieved to date.  Although available solution5

              have not changed significantly through time, the application of the solu-

    5         ~~~tions to specific situations and ocean environments has evolved to the

              present state-of-the-art which, if prudently followed, can lead to suc-

    U         ~~~cessful designs of shoreline protection.

     3             ~~~~The basic types of shoreline protection structures are discussed in

               the following sections. Emphasis is given to a description of the generic

    3         ~~~types rather than detailed characteristics of the variations of each type

               that are possible. Only a brief indication of the structural details

    I         ~~~and construction techniques are given.  In addition to a description of

    3         ~~~the structural alternatives, an analysis of beach nourishment is given.

               This approach is now commonly used for shoreline protection and is one

    3         ~~that is -in harmony  with the natural  processes.  No discussion

                    *                                                           ~~~~~~~~~~~~~~~~~~~~~~27

    3         ~~~is presented in this report of vegetative devices or dune construction.

               These topics are very important to shoreline control and should be used

    I         ~~~as a part of most construction plans. Vegetative devices and dune con-

    3         ~~~struction are covered in Sperling and Edge (1978).

               A Consideration of Alternatives

     3             ~~~~From an engineering perspective, the most often considered engineer-

               ing alternatives include:

      I                 l}~~~~1 beach nourishment,
                        2) seawalls,
      *                ~~~~~3) bulkheads,
                        4) revetments,
      3                ~~~~~~5) groins, and
                        6) jetties and inlet control.

    3         ~~~Each of these alternatives is discussed in turn.

               Beach Nourishment

     I             ~~~~In the past, man has found that some of the best means of protection

    3         ~~~against the sea have come from the imitation of nature's successful

              methods. Beach nourishment is an imitation of nature. It permits more

    5         ~~~of the natural processes to go unhampered.  In the cases where nourish-

              ment is used without other stabilizing devices, an unencumbered area is

    I         ~~provided for recreational uses.  This solution is often considered

    3         ~~~aesthetically better in addition to being safer for use by the public

               than the use of structures. (Fisher et al., 1976). Additionally, a wide

    3         ~~beach provides a large berm for the surging and breaking of waves and is

               also a source of sand for the protective sand dunes and offshore bars.

    I         ~~~The latter are very important in times of storm to act as a submerged

    5         ~~~breakwater and help dissipate the wave energy before it reaches shore.

                    One of the most important considerations in nourishment is the deter-

                    3                                                         ~~~~~~~~~~~~~~~~~~~~~28

             mination of a suitable borrow area. Some past locations used as borrow

    3        ~~sites have either proved ineffective or are now environmentally unusable.

             It is important to find a borrow area as close as possible to keep trans-

    I        ~~portation costs low.  However, an even more important consideration is

    3        ~~the composite grain size characteristics of the borrow site in compari-

             son to that of the natural beach characteristics. To make the

    3        ~~determination more difficult, it is possible to have the grain size dis-

             tribution vary in four different dimensions along the natural beach, a)

    I        ~~along a beach profile intercepting various energy zones, b) parallel

    3        ~~to the beach within one energy zone, c) by depth within the active pro-

             file's sediment envelope, and dJ seasonal changes for the three

    3        ~~dimensional profile (Hobson, 1977).  Therefore, finding a compatible

             borrow site can be difficult. Studies have shown that if it is not pos-

    I        ~~sible to duplicate the characteristics of the natural beach it is better

    *        ~~to have a slightly coarser material if it can economically be found.

    W        ~~This will produce a slightly steeper beach and, most of the smaller

    3        ~~material will be lost.  A finer material may be lost all together and the

             renourishment project could be a failure. One example of this point is

    I        ~~the 1966 renourishment of Cape Hatteras (Dolan, 1972).  Similar situations

    3        ~~occurred at Hilton Head and Hunting Island.

                   Once a potential borrow site is located, a series of calculations

    3        ~~must be made.  Factors'such as the necessary slope of the beach, berm

             width and height, and the placement locations must be resolved. From

    I        ~~these determinations, the required amount of fill is estimated and the

    I        ~~actual transfer of fill to the site can begin.  Once in place, it may

                    *                                                         ~~~~~~~~~~~~~~~~~~~~~29

    I        ~~appear that a nourishment project has lost considerable amounts of sand

    3        ~~over a period of time.  While in reality this occurrence is only a case of

             relocation of the sand into an inner bar system. The sand is still part

    3        ~~of the protection devices that nature uses to help break the energy of

             approaching waves.

     I            ~~~Frequently, nourishment is used in conjunction with other projects.

    I .~~Groin fields are sometimes filled to offset the detrimental effects down-

             drift, while offshore breakwaters are occasionally used to stabilize the

    3       ~~fill behind the breakwater.  However, in some cases the groins and break-

             waters are built to protect the beach fill from being lost and thereby

    3        n~~rolong the time period between renourishment.

     *           ~~~One advantage of nourishment is that it is a short-term technique.

             If for some reason the project results are not beneficial the project can

    3       ~~be abandoned without problems of deteriorating structures.  It is simply

             a matter of not performing the follow-up renourishment schedule. If the

    5       ~~project is to be retained. renourishment must be periodically performed

             to offset the continual losses of sand. Nourishment is not a permanent

             device; it is a continual process.
    3       ~~Seawalls

                  Seawalls are large massive structures built to provide a permanent

    3       ~~separation between the water and land.  They are often confused with bulk-

             heads and revetments which are much lighter structures. Seawalls are

             designed to protect against direct wave action and the associated scour

    3       ~~which frequently occurs with bulkheads and revetments.  An important part

             of most seawalls is a sheet pile cutoff wall to prevent the undermining of

    3       ~~the structure by wave scour, leaching from storm drainage, or wave overtapping

                     *                                                          ~~~~~~~~~~~~~~~~~~~~30

     1        ~~Most  also have some method of dissipating the wave energy.  This could

              be a curved face structure as found in the Galveston Seawall, a stepped

              face as is found in the Gulfport seawall, or a combination of the two as

    3        ~~is found in the San Francisco seawall.  The above are all concrete struc-

              tures, however a seawall need not be of concrete. Many are made of

    I        ~~riprap like the Fernandina Beach, Florida  structure.  Occasionally rip-

    3        ~~rap is placed in front of a seawall for protection from scour at the

              toe. It is not likely that seawalls will be a primary solution on South

    3        ~~Carolina beaches except at the most energetic and developed areas.

              Bulkheads

     I            ~~~~The primary purpose of bulkheads is to retain the fill behind them.

    3        ~~Second, they provide some protection from wave action.  Bulkheads

              are not generally located in a large wave environment. The traditional

    3        ~~bulkhead is a vertical or near vertical structure, usually of a sheet

              pile design with proper penetration to prevent undermining of the founda-

    I         ~~tion by scour.  Riprap is often placed at the base to prevent scour.

    3         ~~These are very common structures in South Carolina.  Most have been ade-

              quately constructed and provide reasonable service; others have not been

    3         ~~as successful.

              Revetments

     I             ~~~~Revetments armor either the bluff or the dune slope.  It is, there-

    3         ~~fore, a sloped structure of either a rigid cast-in-place concrete desivn

              or, more frequently, of a flexible armor (typically rubble) unit type.

    3         ~~In planning a revetment, care must be taken to provide for the relief of

              the wave generated hydrostatic uplift pressure. This is commonly done

    I         ~~by providing a filter layer of either cloth or crushed stone to allow

    3         ~~~the pressure to dissipate with a loss of material behind the structure.

                                                                  31

    Several types of intlerlocking blocks have been developed for use as re-

    vetments (Mohl et al., 1967).  A second type of precast block which does

    not interlock is simply laid on top of a filter layer. Gobi blocks and

    nonlocking concrete blocks are examples (McCartney et al., 1977).  An

    advantage of this type revetment structure is the ease of installation.

    Blocks are not the only type of man-made structures used in forming re-

    vetments--concrete dolos or stapod units may be chosen.  Synthetic bags

    filled with either sand or concrete and placed along the slope can be

    used.  A mat type form is also available to form the revetment (Intrusion-

    Prepakt, 1975).  Not all revetments are of man-made materials.  Rubble

    revetments work very well where materials are readily available as well.

         Revetments, like seawalls and bulkheads, are designed only to protect

    areas behind them anything forward will not be protected by the struc-

    ture.  In fact, unless they are used in combination with other protection

    devices, they may well lead to the destruction of the area to the front

    and the sides of the structure.  This accelerates the erosion in the area

    and will eventually lead to the failure of the structure unless adequate

    protection is given to the structure. The sheet pile prevents a rapid

    seaward flow of the groundwater drainage but encourages erosion of the

    areas to the front of the wall. The area to the sides of these struc-

    tures may be eroded due to the reflection and concentration of wave energy.

    It is for this reason that these structures are not usually satisfactory

    in protecting small areas of shorefront.

    Groins

         Groins are very common along the South Carolina Coastline. They have

                    1                                                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~-32

    *        ~~been quite successful in some applications while some installations have

             not only been unsuccessful but have contributed to additional erosion.

             The groin is a long, low, narrow structure, usually starting at a point

    3        ~~landward of the predicted shoreline and running perpendicular to the

              coast into the water. Groins are classified by their design type and

    3        ~~may be high or low, long or short, permeable or impermeable, as well as

              fixed or adjustable. Groins must always be built as a system covering

    I        ~~the desired area.  A single groin should never be used except as a termi-

    3        ~~nal structure to retain sand at the end of a project or to keep it out

              of an inlet.

     3            ~~~~The function of a groin field is to trap the moving sand in the lit-

              toral zone. This sand is deposited on the beach in the vicinity of the

    U        ~~updrift side of the groin.  Unfortunately, if a single groin is used the

    3        ~~downdrift side is deprived of the moving sand; therefore, the groin may

              actually cause erosion immediately downdrift. In South Carolina, the

    5        ~~groin normally extends out into the water to approximately the six foot

              contour on the South Atlantic coast. To extend the groin farther out is

    *        ~~uneconomical as most of the littoral drift movement is within the zone

    3        ~~landward of the normal breaker line.  If the groin is too long and com-

              pletely blocks the littoral drift, the downdrift area will be severely

    3        ~~eroded.  A second possibility is that the drift will be pushed offshore

              and lost to the area entirely.

     I            ~~~~A number of methods have been developed to control the downdrift ero-

    3        ~~sion.  The low groin, for example, permits the overtopping of the groin in

              periods of storm wave attack or high tide. The littoral drift is there-

    3        ~~fore not completely blocked.  A permeable groin obtains the same action

                    *                                                           ~~~~~~~~~~~~~~~~~~~~~33

    1        ~~by allowing the drift to actually move through openings in the groin.

    3        ~~Care should be taken to keep these groins permeable as marine-growth will

              sometimes block the flow. Permeable groins do have the advantage that

    I        ~~the sand will usually build up on both sides of the groin.  Shore groins

             work by not completely stopping the flow; however, they should be long

             enough to stop some of the drift. Often groins are used in conjunction
    *        ~~with beach nourishment to slow the rate of erosion from the beach face.

              It must be emphasized that groins will not work unless there is a sizable

    3        ~~gross drift.

             Jetties and Inlet Control

     1            ~~~A jetty is a device which extends from the shore out into the water

    3        ~~much like a groin, yet its function is quite different.  The jetty

              is used to control inlet areas, to help prevent shoaling, or to direct

    3        ~~and confine an inlet or river.  It may also act like a breakwater by pro-

             tecting a channel entrance against wave action and cross currents. While

    U        ~~not always necessaryjetties are usually built in pairs, one on each side

    3        ~~of the channel.  They are fairly long structures, generally longer than

             the groins they resemble. The jetties at MIurrellls Inlet, for example, are-

    3        ~~several thousand feet long.  They also are quite massive; the Humblodt

             Jetties in California have 43 ton dolosse units as a part of their struc-

    I        ~~ture (Magoon et al., 1976).  The actual design of a jetty structure is

    3        ~~quite complex and, due to the siting problems, professional help should

             be obtained.

     3            ~~~While jetties protect inlet areas, they do present problems.  Because

             of their length, they extend well out into the littoral drift zone, in

    I        ~~some cases blocking it entirely.  However, techniques have been developed

                    I                                                          ~~~~~~~~~~~~~~~~~~~~~34

    U        ~~to prevent the windrift erosion.  Special impoundment areas are developed

              into the jetty design with methods to transfer the sand to the downdrift

              side. This feature may be an elaborate sand pumping system with float-

    3        ~~ing dredges or fixed pump systems (U. S. Army COE, 1973).

                   As far as coastal erosion is concerned, jetties can be important

              factors in controlling that erosion caused by dynamic, shifting inlets.

    3        ~~Of course even in this regard they provide navigational benefits.

              Breakwaters

                  A breakwater is by definition "a structure protecting a shore area,

             harbor, anchorage, or basin from waves." (U.S. Army COE, 1977). The

    1        ~~above definition is purely navigational, not indicating any erosion con-

              trol aid. However, as the structure does exist in the littoral drift

             area, it sets up erosion and accretion patterns.

     3            ~~~Within the past decade considerable emphasis has been placed on the

             concept of the crenulate bay and headland defense. Silvester (1974) ad-

    I        ~~vocates the use of the artificial headland, or breakwater, to imitate

    3        ~~natural defense mechanisms.  The concept is not new, an offshore break-

             water system was completed in Venice, California, in 1904. In spite of

    5        ~~the use of the artificial headland for such a considerable period, de-

             sign criteria is quite lacking (Magoon and Edge, 1978).

     I            ~~~Actually the offshore breakwater is used in two distinct ways to con-

    3        ~~trol erosion.  One is the artificial headland concept mentioned above and

             the other is as a sand trap. The breakwater works as an erosion control

    3        ~~device because of its wave calming action.  Some of the wave energy is

             reflected back out to sea by the breakwater, some may be transmitted, but

    I        ~~at considerably lower energy levels, and some waves are diffracted around

    3 ~~the ends of the breakwater. W~hen the wave shadow of the breakwater enters

                    I                                                         ~~~~~~~~~~~~~~~~~~~~~35

    I        ~~into the littoral drift zone, the ability to transport sediment is lowered

    3        ~~in that area and the sediment is dropped.  The shore tends to build to-

              ward the breakwater. However, it represents a blockage to the littoral

    5        ~~drift and illustrates the erosion deposition features associated with

              groins. By the placement of such a breakwater just updrift of an inlet,

    I        ~~an effective sand trap can be developed to help stop inlet shoaling and

    3        ~~provide a convenient location for pumvine sand around the inlet.  The

              breakwater at Channel Islands Harbor, California, is an excellent exam-

    3        ~~ple of this use of breakwaters.

                   Offshore-shore connected is only one descriptive category of break-

    I        ~~waters, there are several other categories.  Not all breakwaters are built

              to exist above the water level; some are submerged, even at low tide. The

              submerged breakwater accentuates the wave enerey and has the added advan-

    3        ~~tage of not interfering with the aesthetic qualities of the view.  The

              submerged breakwater does present somewhat of a navigation problem in

    I        ~~that it must be well marked.  They are, however, less expensive to build.

    *        ~~Wave accentuation to provide a better bathing beach area was the goal of

             one scheme at Rat-Yam, Israel. The submerged breakwater proved to be the

    3        ~~best overall design (Taunman, 1976).  Most breakwaters are fixed in loca-

             tion; however, a few are mobile. Silvester (1974) discusses the ability

    3        ~~to use mobile breakwaters to build up large sections of a shoreline by

             the progressive movement of the breakwaters offshore (Silvester, 1974).

                                      Selection of Alternatives

     3            ~~~The actual selection of a shore protection device is dependent on the

             dynamics of the area; what might work very well in one area could be di-

    3        ~~sastrous under different environmental conditions.  Hubbard et al. (1977)

                                                                             36

     1       ~~have divided the 255 km South Carolina coastline into three zones; arcu-

              ate strand, cuspate delta, and barrier island. Each zone has its own

              unique dynamics and, therefore,different erosion control techniques would

              apply to each.

      3           ~~~Many devices are used in combination rather than alone, for example,

              offshore breakwaters and groins are often used with beach nourishment.

              Each of the three zones must be studied in detail to determine both the
     I        ~~dynamics of the zone and the need for erosion control.  It is anticipated

              that several devices could be selected as workable in some areas. The

     *        ~~final selection of a device for a particular site will have to be made

              based on a detailed engineering analysis, an economic study of the area

              and a review of the total costs and effectiveness of each device under
    I.       ~~consideration.

                   A number of lists of available devices have been published which

    3        ~~could be used in selecting an appropriate alternative for erosion control.

              Sperling and Edge (1978) and Dames & Moore (1980) are examples of recent

    I        ~~lists of the characteristics of various types of devices.  In these lists,

    3        ~~erosion control devices are presented with short comments on their indi-

              vidual requirements and problems encountered in their general use.

    I        ~~Subheadings appear under each control device on types of materials avail-

              able for use. Additional comments are included on specific problems and

    I        ~~requirements for each of these materials.  Specific examples of material

    3        ~~types and forms are listed along with a location of where they have been

              used and a rating of their performance. There is one final column on

    3        ~~approximate cost per foot of protection  which has only been filled in

              where recent information is available. It is emphasized that this infor-

    I        ~~mation must be used with extreme caution as low cost protection devices

    3        ~~have been included in the chart along with the "high cost" units.

                                                                   37

                                  BIBLIOGRAPHY

    Armstrong, John M., "Low-Cost Shore Protection on the Great Lakes:  A
         Demonstration/Research Program," Proceedings Fifteenth International
         Conference on Coastal Engineering, ASCE (1976).

    Dames & Moore, "Draft Master Plan for Shoreline Erosion Protection" pre-
         pared for Department of Environmental Protection, New Jersey (1980).

    Dolan, Robert, Beach Erosion and Beach Nourishment, Cape Hatteras, North
         Carolina, Dune Stabilization Study, Natural Resource Report No. 4,
         U.S.

    Edge, Billy L., John G. Housley, and George M. Natts, "Low-Cost Shoreline
         Protection, "Proceedings Fifteenth International Conference on Coas-
         tal Engineering, ASCE (1976).

    Edge, Billy L. and Adrain J. Combe, "Low Cost Shore Protection," Proceed-
         ings Coastal Zone 1978, ASCE (1976).

    Fisher, John S. and Nelson N. Felder, "Cape Hatteras Beach Nourishment,"
         Proceedings Fifteenth International Conference on Coastal Engineer-
         ing, ASCE (1976).

    Fried, I.., "Protection by Means of Offshore Breakwaters," Proceedings
         Fifteenth International Conference on Coastal Engineering, ASCE (1976).

    Hobson, R. D., Review of Design Elements for Beach-Fill Evaluation, Techni-
         cal Paper No. 77-6, U.S. Army Corps of Engineers, June (1977).

    Hubbard, Dennis K., Miles 0. Hayes, and P. Jeffrey Brown, "Beach Erosion
         Trends Along South Carolina Coast," Proceedings Coastal Sediments 1977,
         ASCE.

    Intrusion-Prepakt, Inc., Erosion Control Devices and Methods, Report sub-
         mitted to SEAP, U.S. Army Corps of Engineers, December (1976).

    Komar, Paul D. and Thomas A. Terich, "Changes Due to Jetties at Tallamook
         Bay, Oregon, "Proceedings Fifteenth International Conference on
         Coastal Engineering, ASCE, (1976).

    Machemehl, Jerry L., "An Engineering Evaluation of Low Cost Stabilization
         Projects in Brunswick County, North Carolina, "Proceedings Coastal
         Sediments 1977", ASCE (1977).

    Magoon, Orville T., Robert L. Sloan and Nobujuki Shimizu, "Design and Con-
         struction of Humboldt Jetties, 1880-1975, "Proceedings Fifteenth
         International Conference on Coastal Engineering, ASCE (1976).

                                                                   38

    McCartney, Bruce L. and John P. Ahrens, Stability of Gobi Block Revetment
         to Wave Attack, Technical Memorandum No. 55, U.S. Army Corps of Engi-
         neers, October (1977).

    Mohl, Edgar V. and James D. Brown, "Flexible Revetment Using Interlocking
         Concrete B-ocks, Tilghman Island, Maryland," Shore and Beach, October
         (1967).

    O'Brien, Morrough P. and Joe W. Johnson, "The Stabilized Approach," Pro-
         ceedings Coastal Zone 1980, Vol. IV, ASCE (1980).

    Pilkey, Orrin and Warren Kaufman, The Beaches Are Moving, van Nostran Press
         (1980).

    Seabergh, William C., "Jetty Design for Little River Inlet, South Carolina,"
         Proceedings Coastal Sediments 1977, ASCE (1977).

    Shemdin, 0. H., H. K. Brooks, A. Ceylanli and S. L. Harrell, "Comprehensive
         Monitoring of a Beach Restoration Project," Proceedings Fifteenth
         International Conference on Coastal Engineering, ASCE (1976).

    Silvester, Richard, Coastal Engineering, 2, Elsevier Scientific Publishing
         Company (1974).

    Sperling, Pam and Billy L. Edge, "Engineering Solutions to Coastal Erosion,"
         Department of Civil Engineering, Clemson University (1978).

    Tauman, Joseph, "Enclosing Scheme for Bathing-Beach Development," Proceed-
         ings Fifteenth International Conference on Coastal Engineering,
         ASCE (1976).

    Toyoshima, 0., Practical Coastal Technology: Erosion, in Japanese (1972).

    U.S. Army Corps of Engineers, Shore Protection Guidelines, August (1971).

    U.S. Army Corps of Engineers, Shore Protection Manual,, 3 Volumes, CERC (1977).

    U.S. Army Corps of Engineers, Cooperative Beach Erosion Control Project at
         Lakeview Park, Lorain, Ohio, Buffalo District Engineers, June (1975).

                                  CHAPTER IV

                     THE MAAGEMENT OF COASTAL DEVELOPMENT

        Coastal processes have been at work since time invariant, creating

    a volatile physical condition.  As a result, the formation of the pre-

    sent barrier island chain along the Atlantic and Gulf Coasts has been

    both created and significantly changed over time. Although these

    changes have been long-term, losses in terms of real property have

    increased significantly in recent years. These property losses have

    resulted in large part due to the rapid development of beach areas since

    the end of the Second World War and to some short-sighted building prac-

    tices that have failed to appreciate the dynamic nature of the physical

    environment.

         Although intensive development is a relatively recent phenomenon,

    South Carolina planters were building summer beach cottages by the late

    1700's. Among the first locations were Pawley's Island and Edingsville

    where relief was sought from the hot summer climate and cool nights on

    the plantation from which it was felt malaria bred (Prevoost and Wilder,

    1972') At Edingsville, Sea Island cotton was soon introduced and proved

    so profitable that by 1820 there existed sixty large "comfortable" houses

    (Crayden, 1955.) In Charleston, where heat and occasional outbreaks of

    yellow fever made summers unpleasant, residents began to make use of near-

    by Sullivan's Island. A legislative resolution of 1791 granted the right to

    spend the summer on the island to any South Carolinian who thought it "bene-

    ficial to health".  By 1880, streets were laid out, and by 1824, the summer

    population was said to be "a thousand or more" (Brewster, 1947.)

                                                                  40

         Development of the Grand Strand area of South Carolina, now the

    state's most popular resort area, began after the turn of this century

    with the majority of development occurring in the post-war

    period. Despite out-migration from rural areas, the population of

    Horry County which includes Myrtle Beach doubled between 1930 and 1976.1

    Still more recently, the number of visitors to the Grand Strand grew

    from 2.9 million in 1972 to 6.5 million in 1978 despite the attention
                                                 2
    given gasoline shortages and price increases.   While the  Grand Strand

    has become one of the most popular vacation areas on the Atlantic Coast,

    exclusive resort communities have developed further down the coast at

    Hilton Head, Fripp, Kiawah, and Seabrook Islands.  The most significant

    development of the group has been Hilton Head where population in-

    creased from 1,000 in 1960 to 2,546 in 1970 and is estimated to be 10,:500
            3
    in 1980. The value of building permits issued over the past decade which

    increased from $12 to $91 million is further indication of this growth.4

         This recent development of oceanfront beaches has provided greater

    accessibility for vacation and year-round accommodations. In turn,

    benefits have accrued to a far wider audience, and an important tourism

    industry has spawned in South Carolina as well as other coastal states.

    This development has not been without cost with much of it occurring in

    hazard areas subject not only to long-term recession but also to storm

    and flood damage. In addition, the cumulative effect of the demands

    being placed on the delicate coastal ecosystem requires careful attention.

         The following chapter will examine in greater detail the peculiar

    benefits and costs associated with such development and the private and

    institutional inducements that have contributed to this growth.  The

              chapter will also consider the present use of coastal resources and

    3        ~~examine the appropriate role of the public sector in effecting optimal

             use of the resource.

          I                           ~~~~~~~~inducement to Development

                  A number of factors have contributed to rapid development in

             coastal areas. One of the more significant factors has been climatic.

    3       ~~Since 1960, the number of hurricanes striking the Atlantic coast has

             been unusually sparse with no major hurricanes having occurred during

    I        ~~this time period.  Although the present trend is cyclical rather than

    u        ~~permanent, a feeling of security has arisen among coastal residents,
             many of them new to the coast. In Florida, for example, it is estimated

    3        ~~that 90 percent of coastal residents have never witnessed a major

             hurricane.5 This influence is felt not only in the quantity of deve-

    I        ~~lopmnents but also in terms of quality as building patterns reflect a

             lack of appreciation for dynamic natural processes. The remaining

             inducements can be generalized as being either privately or publicly

    3        ~~inspired.

             Private Incentives

     I            ~~~Among economic and demographic factors that have contributed to the

             rapid development, the most significant appear to have been:

                        1) growth in personal income,

      3                ~~~~~2)  a shift in the geographic distribution of the

                            population,

      3                ~~~~~3)  improved accessibility, and

                        4) learned behavior patterns of users.

                   3~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 42

     I           ~~~Since World War 11, the real per capita income in the United States

    �       ~~has risen 33 percent.6 Although increased leisure time often has been cited

            as a reason for increased recreational demand, the greater involvement of

            women in the work force has actually decreased family leisure time.7 The

            more important factor stems from higher standards of living, allowing the

    I       ~~same wage-earner or family to participate in more expensive, capital-

    i       ~~intensive recreational activities.  As a result of this phenomenon,

            the beaches have been transformed from the playground of the rich to

    5       ~~increasingly include the vast middle class.

                 A second factor contributing to this trend is the shift in geograp-

            hic distribution of the population. Presently, 50 percent of the

            population in the United States resides within 50 miles of the coast.8

    U       ~~Physical proximity is further reinforced by increased accessibility via

    3 ~~the private automobile and better transportation arteries, especially

            since the advent of the interstate highway system. Consequently over

    5 ~~the last two decades, frequent day and weekend excursions have become

            feasible in strictly physical terms to a wider segment of the population.

     I          ~~~Collectively, the increased accessibility to broader income classes

            and geographic regions has introduced regular beach visits to a far

            wider audience.  This exposure has led to a secondary effect in terms of                   A

    3 ~~learned behavior patters by individuals and families. In other words,

            once exposed to various recreational activities a greater appreciation of

    I ~~the activity may be gained, i.e., a "learning by doing" phenomenon

    3       ~~(Krutilla, 1967.)  A recent study by the South Carolina Department of

            Parks, Recreation, and Tourism indicated that half of the individuals

                   1~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ "3

             surveyed listed beach swimming as an activity that they participated

    3        ~~in during the one-year study period.9

             Institutional Inducements

                  In addition to private inducement, a number of federal activities

             have stimulated and subsidized development of coastal areas. Activities

             having both direct and indirect effects on development include bridge

    3        ~~and highway construction, shoreline protection, flood insurance,

             wastewater treatment facility grants, small business loans, economic

    I        ~~development grants, urban planning assistance., and home mortgage in-

    g        ~~surance.  A brief discussion of the role of each of these programs

             in stimulating development is presented in the sections to follow.

             Bridge and Highway Construction Programs:

                  Bridge construction is vital to barrier island development since

    U        ~~development costs would be prohibitive in most cases without easy

    5        ~~island access.  As a result, the federal government authorizes bridge

             construction and road system development to facilitate access. In

    I        ~~addition., if th~e bridge or road. is part of a planned highway system,

             the government may provide funding toward its construction as well.

     I            ~~~~Road and bridge construction programs are administered by the

    3        ~~Department of Transportation, the bridge permit program is administered

             by the U. S. Coast Guard, and the road construction grant program is

    I        ~~administered by the Federal Highway Administration.  The Coast Guard

             has had authority to review bridge construction proposals since 1966.

    I        ~~Notwithstanding bridge statutes, the Code of Federal Regulations, and

             case law, a bridge permit has never been denied by the Coast Guard

             because of environmental impact. 10

                  The road construction grant program as administered by the Federal

                    1                                                         ~~~~~~~~~~~~~~~~~~~~~44

              Highway Administration is an important influence in determining land-

    3        ~~use patterns.  This multi-billion dollar per year construction program

              makes it practical and economically rewarding to convert from low to

              high-density developments. Road construction, by improving accessi-
              bility, increases pressures for residential, recreational and comnm-

              ercial uses.

    3        ~~Shoreline Protection Programs:

                   One of the most influential agencies on coastal development is

    I        ~~the U. S. Army Corps of Engineers.  Since the Rivers and Harbors Act

    g        ~~of 1899, the Corps of Engineers has had responsibility for navigational

              projects and flood control. Traditionally, the Corps has favored

    I         ~~structural solutions to flood control, beach erosion  and navigational

              problems. Construction of such projects has involved local rises in

    I         ~~employment and attendant rises in demand for housing and services.

     5             ~~~~A secondary factor involves the enhancement of recreation brought

              about by the proposed project. Enhanced value may be claimed as a

    3         ~~project benefit if the beach is either publicly owned or open to public

              use. Moreover, the federal government is prohibited from participating

    �         ~~in a shore protection project unless the public will have access to

    j         ~~the shoreline in the project area.  This requirement means federal

              projects often create public access to areas previously denied to the

    I.        ~~public.

              Flood Insurance Programs:

     ~~~~~iIn order to be eligible for federal financial assistance for ac-

    5         ~~quisition or construction purposes in time of disaster, communities in

              special flood hazard areas must enter the National Flood Insurance Pro-

                    3                                                         ~~~~~~~~~~~~~~~~~~~~~45

           gram. (This provision is part of the Flood Disaster Act of 1973.) The

           goals of the National Flood Insurance Program as administered by the

           Federal Insurance Administration are to encourage state and local

    I      ~~governments to make adjustments to constrict development of land in

           flood hazard areas and to impose tighter building codes to minimize

           damage caused by flood losses. Before a community is offered flood in-

    j ~~surance, it must institute flood-plain management regulations.

           However, enforcement and administration of these regulations generally

    5 ~has'been inconsistent and ineffective in the past. In an attempt to

           encourage sound management practices, FIA offers low flood insurance

           premiums to residents of coastal areas. The distribution of risk to

    5      ~residents of hazard and non-hazard areas has caused coastal residents

           to discount the risk factor along the oceanfront. Although often given

    I      ~more than just credit for influencing development, it has been estimated

    5~~that federal subsidies  for flood insurance amount to only 6percent to

           public expenditures on barrier islands.   Still., the psychic as well as

    3     ~monetary influence of the program is greater than that figure.  Congres-

           sional Review of the program in the next legislative session will provide

    �      ~a reading of Congressional sentiment toward such programs.

                Many financial institutions refused to grant mortgages in coastal

           areas prior to the National Flood Insurance Program because of the
    5     ~high risk of coastal development.  However, as flood insurance became

           available, banks reversed their previous policy of denying construction

    5     ~loans in hazardous areas.  In this way, tax money supports insurance

                     1                                                          ~~~~~~~~~~~~~~~~~~~~46

              and development in flood-prone and ecologically fragile areas.

    5        ~~Wastewater Treatment Facilities Grants:

                   Grants for the construction of wastewater treatment facilities

    1        ~~are primarily funded by the Environmental Protection Agency (EPA), the

    5        ~~Department of Housing and Urban Development (HUD), the Farmers Home

              Administration (FniHA) and the Economic Development Administration (EDA).

    3        ~~HUD's emphasis is urban and FmHA's is primarily rural.  In terms of

              wastewater treatmentEDA's program is small when compared to the other

    I        ~~agencies mentioned.

     I            ~~~~Section 201 of the Federal Water Pollution Control Act Amendment

              of 1972 authorizes EPA to grant up to 75% of the cost of construction
                                                       11
    I       ~ ~~of new wastewater treatment facilities.    A problem arises from the
              fact that inadequate areawide planning may precede construction of these

              facilities.  12When poorly planned, 201 projects contribute to growth

    I         ~~which may lead undesirable residential and commercial growth in coastal

              areas.

     5             ~~~~Regulations of the EPA do not specifically designate coastal areas

              as areas of environmental concern. By concentrating more on the ade-

    I         ~~quacy of the justification and design of the wastewater treatment

    1         ~~facilities, environmental assessments are left to engineering firms

              which may be unaware of the special conditions of coastal areas. This

    5         ~~specifically contributes to construction which might otherwise be

              prohibited.

    I         ~~~Small Business Loans:

     5             ~~~~The Small Business Administration (SBA) provides two types of

                    3                                                        ~~~~~~~~~~~~~~~~~~~47

            direct or guaranteed /insured loans- -B-conomic Injury Disaster Loans

    I      ~~and Physical Disaster Loans.  These loans are designed to assist

            business concerns which suffer economic injury due to designated

            disasters and to restore damaged property to predisaster conditions.

    5      ~~These loans are granted for up to thirty years at relatively low interest

            rates.

     3          ~~~Physical disaster loans are made to individuals, businesses,

            churches, private schools, hospitals, colleges and universities.

            This broad range of disaster assistance eligibility contributes to a
            reduction in concern for hazardous area development.

                 Further., an amendment to the Federal Water Pollution Control Act

    5 ~~of 1972 authorizes the SBA to make loans of up to 90% of the cost

            small businesses incur by making additions to, or alterations in,

    S      ~~facilities required for water pollution control.  This concern, in

    I      ~~effect, is removed for businesses considering construction in coastal

            areas.

    j      ~~Economic Development Grants:

                 Under the provisions of the Public Works & Economic Development

    � ~~Act of 1965, the Economic Development Administration has primary

    5      ~responsibility for the Economic Development Grants program.  Deve lop-

            ment grants can be used for such public facilities as access roads to

    5      ~~industrial1 areas, water & sewer systems, harbor facilities, flood

            control projects and site improvements for industrial parks. These

    I      ~~grants are made for up to 50 percent of the development cost; however,

    5 ~~severely depressed areas may receive supplemental grants to bring

            the federal contribution to as high as 80 percent of cost.

                                                                          48

     I          ~~~Loans, available for public works and development facility projects,

    3 ~~may pay the full cost of a project and run as long as 40 years. A

           community unable to provide a share of the cost may receive a grant

    3 ~~for 50 percent of the cost plus a federal loan for the remainder. Such

           grants and loans designed to provide public facilities on barrier

    I ~~islands contribute to development for urban use. Urban Planning

           Assistance grants through HUJD similarly facilitate the development of

           comprehensive plans'for construction and capital improvement programs.

    3      ~~Home Mortgage Insurance:

                By insuring commercial lenders against capital loss, the Federal

    3 ~~Housing Administration encourages these lenders to invest in the home

           mortgage market. Loans are insured by FHA for up to 97 percent of

           value for up to 30 years. The loans finance homes in urban areas as

    3      ~well as in rural areas where construction standards are less rigid.

           Neither the FHA nor the FmHA differentiates between barrier islands

    5      ~or mainland  sites in program administration.

                                  The'Benefit of DeVelopment

                Recreational benefit is difficult to quantify, Ile know that the

    I     ~minimum benefit derived is that amount individuals pay for the activity.

           Yet, as the beaches are held in public trust and, in general, are non-

    3     ~exclusionary, payments are made only -for ancillary services, food, and

           accommodations. As a result, the expenditures on beach related services

    I     ~represent a first approximation for much of the benefit derived from

    5     ~beach experiences.  In 1976, $845 million in travel expenditures were

           spent in the 6 oceanfront counties in South Carolina. 13 Hiorry and

    5     ~Charleston Counties rank first and second respectively in travel ex-

                    1                                                         ~~~~~~~~~~~~~~~~~~~~~49

    I        ~~penditures and together account for 41 percent of such expenditures

    5        ~~among the 46 counties in the state.    14Particularly for the coastal

              counties, tourism represents a significant component of the economic

              base. For the state as a whole, tourism ranks as the second most

              significant industry, and tourist related employment as of 1975 totaled

    1        ~~28,274 (Ellerbrock and Hite, 1979).

     3            ~~~~Properties adjacent to the beach or within its influence reflect

              differential rent, i.e. aesthetic value due to location. Much of this

    I        ~~value is captured in land prices for both residential and commercial

              property. It is estimated, for example, that oceanfront property at

    I        ~~Myrtle Beach sells for a 50 percent premium, compared with comparable Pro-

    3        ~~perty on the second row.    isAs development continues in coastal areas,

              the beaches and adjacent properties become scarce commodities. Ocean-

    3        ~~front properties then demand scarcity rent, i.e. value above and beyond

              normal returns on investment, because of their location. Findings of

    I        ~~the present study suggest, for instance, that despite the recent down-

    3        ~~turn in the housing market, properties at Hilton Head appreciated at

              an annual rate of 25.4 percent between 1978 and 1980.    At the same

    3        ~~time, the natural aesthetics of beach areas become increasingly valuable

              due both to increased demand and to limited available supply. Although

    I        ~~landowners should be encouraged to make the highest possible use of their

              properties, it is from the ocean and the beach that private properties

              gain value and not vice versa. 16Collective benefit is achieved, there-

    5        ~~fore, through long-term maintenance of the aesthetic qualities of beaches.

                    1                                                           50~~~~~~~~~~~~~~~~~~s

                   In addition to pecuniary benefits derived from the coast, signifi-

              cant nonmarket benefits may accrue as well. Because beaches are public

              and, in general, no fees are charged for their use, the use value de-

    I        ~~rived from beach visits may exceed the price paid.  Economists refer

              to this outcome as consumer's surplus, implying that the benefit derived

              exceeds the market price. To stereotype an example, a surfer who camps

    3        ~~on the beach may derive a great deal of pleasure despite minimal expen-

              ditures. The day user may derive significant personal benefit with

    1        ~~minimal or no expenditure within the beach community, while, at the

    1        ~~same time, the therapeutic properties of the beach produce social benefit.

              Despite the fact that these activities occur without transaction, they

    3        ~~represent significant value to beach users and therefore must be approx-

              imnated to accurately reflect social value. In the case studies to

    I         ~~follow, a value for beach user days will be assigned.

                   Finally, whether we use the beach or not, value is derived from the

              option of doing so. For example, an individual that has never visited

    3        ~~the Grand Canyon (or South Carolina beaches) may derive option value

              from knowing that the canyon exists and that he/she and his/her

    5         ~~descendents may at some time derive enjoyment from that experience.

              Implicit in the concept of option value is the fact that alterations

              of the natural environment may be irreversible. Changes to the coastal

    I        ~~ecosystem,for example,rnay diminish or eliminate the resources environ-

              mental amenity.

     5            ~~~~The benefit derived from the coastline has resulted in increased

              usage and development for residential and commercial purposes. It is

    appropriate, given the public nature of the resource, to consider the

    consequences of this development and to consider the appropriate role

    of the public sector in affecting maximum long-term enjoyment of the

    beaches.

                             The Cost of Development

         Development in coastal areas is not without cost, some of which is

    peculiar to oceanfront environs.  The most obvious cost differential

    associated with such development is the risk to life and property as

    the result of locations in areas subject to coastal hazards and long-

    term erosion rates.  In 1969, Hurricane Camille, with a rating of five

    on a scale of five and a 24-foot storm surge, caused over $1 billion in

    property loss.  Additionally, 144 lives were lost for which we do not

    wish to place values. In 1900, the most destructive storm to date hit

    Galveston, drowning 6,000 residents and killing another 2,000 on shore

    (MacLeish, 1980).  More  subtly,  it is estimated that annual losses

    due to coastal erosion amount to $300 million (Sorenson and Mitchell,

    1975). Attempts to alleviate the property loss from shore erosion

    gre certainly not without cost. It is estimated, for example, that

    a beach nourishment program in progress by the City of Miami Beach will

    amount to $64 million.

         The fact remains that the risk of property loss due to natural

    forces is a risk incurred from coastal development.  Attempts to mini-

    mize that risk are also with cost whether the solutions are of a(n)

    engineering, management, or information variety.  As indicated above

    the costs can, in some cases, be quite significant.

                    5                                                          ~~~~~~~~~~~~~~~~~~~~~52

                   The cost in terms of environmental damage stemming from coastal

    I        ~~development may also be large.  The salt marshes lying behind barrier

              islands and coastal   reaches are the most productive ecosystem on

    j        ~~earth.  More than 70 percent of coastal fish and shellfish breed in

              these waters and hundreds of wildlife species inhabit the waters or

    I        ~~adjacent lands (Clark, 1977).  Although capable of a large assimilative

    3        ~~capacity and sewage discharge, construction patterns, in some cases,

              have had serious effects on the ecosystem. Depletion of ground water

    3 ~~reserves and the resultant effect of saltwater intrusion have accornpani-aj

              development in a number of instances. Attempts to alleviate or miti-

              gate for these effects have been costly. Public service delivery

    j         ~~likewise has been costly due to the remoteness of many oceanfront areas

              and their seasonal nature which often results in excess capacity to be

    I        ~~maintained during the off-season.

                   More subtlely perhaps, the actions of man by disturbing the natural

              system may exacerbate erosional trends and thereby property loss. It is

    3        ~~well understood now that the earlier leveling of dune systems and the

              removal of beach vegetation has had serious consequences. Intensive

    I        ~~development also has limited the absorbability of the land resulting in

              serious problems with stormwater runoff. The City of Myrtle Beach is a

    I        ~~case in point where discharges onto the beach currently violate water

    3        ~~quality standards and contribute to beach erosion.  Aesthetically, the

              better than 280 discharge pipes represent a further cost to the commu-

    5        ~~nity (Waccamaw Regional Planning Commission, 1980).

                   Attempts to lessen the effect of erosion, although well-intent-

    I        ~~ioned., have occasionally caused more harm than good and, at other times,

                    1                                                           ~~~~~~~~~~~~~~~~~~~~53

    I        ~~merely redirected wave energy causing erosion elsewhere.  A 1930's

    3        ~~WPC program to rebuild the dune system at Cape Hatteras built 9-foot

             dunes to assure that sufficient sand was stored to withstand the most

    I        ~~severe storm.  Natural washover effects were eliminated, preventing

             relocation of the dunes and leaving them helpless admidst the retreat-

    I .~~ing shoreline (Leatherman, 1978). Seawalls and bulkheads, built to

    j        ~~protect landward property, cause wrap-around action resulting in erosion

             to adjacent property. At the same time, the wave energy is directed

    3        ~~downward at the base of the structure, undermining the structure and

             accelerating erosion rates seaward of the construction. As the scower-

    I        ~~ing effects are likely to occur below mean - high - water, the

    3        ~~property loss is to public lands.

                  Finally, stop gap measures to control structural changes which

    j        ~~alter sand transport patterns may hasten erosion rates.  Ironically,

             many of these structures are built as a preventive measure. To the

    I        ~~degree that sand is robbed from adjacent landowners and/or the public,

             that portion of the cost is borne externally to the landowner. Struc-

             tural solutions to alleviate erosional loss should be allowed only in

    3        ~~the most severe cases or  where external effects are deemed to be small.

             Still, a means of compensation for injured parties should be incorpo-

    I        ~~rated subject to prior approval or subsequent arbitration.

                                                                   54

                         The Optimal Use of the Resource

         Although dynamic, coastal processes are in continuous equilibrium.

    Sand budgets remain in balance albeit positioned in varying proportions

    depending on seasonal or climatic conditions.  The disequilibrium  that

    has developed along coastal beaches evolves instead from a conflict

    between man's desire for stable land-use patterns amidst volatile nat-

    ural conditions. The resolution of this issue requires a balancing of

    objectives regarding the proper use of the resource, i.e., the coastal

    environment.

         In order to achieve efficient solutions, resources should be used

    to the point where the value derived from the last unit is equal to the

    cost of accessibility.  This situation is indicated in figure IV-1 on the

    following page depicting the marginal benefit and cost derived from

    beach utilization.  The marginal benefit, MB, reflects enjoyment from

    the last unit of activity.  It is downward sloping as, beyond some point,

    the value from additional use becomes less and less significant through

    saturation.  The marginal cost, MC, reflects the expenditure required

    for access to the activity. As shown, costs are assumed to be constant

    for each user occasion.  From a private perspective, where MC  reflects

    private cost, collective use will occur at point U1 at the cost of V1.

    Individuals, it should be noted, will not utilize the resource where

    their personal cost exceeds the benefit to be derived.  To provide for

    greater collective benefit, public programs have lowered, in effect,the

    cost of accessibility by subsidizing development as well as by reducing

    the inherent risk to property owners. Conceptually, the effect is to

    Value                \
                                                           /, MC3

        V3  _ _ _  _ _

        V2                              i"  _ __MC2

                               U3    U1           U2    Utilization

            Figure IV-1. The marginal benefit and cost accruing
                          from beach usage.

                                                                  56

    lower marginal cost to MC2; utilization is increased thereby from UI to

    U2 meeting the program objectives.  From a standpoint of efficiency, this

    solution may not be optimal as the true cost, MC1, exceeds private benefit

    of the last visit by the amount of the subsidy, V1 - V2.  Yet, we have
    not included the social benefit associated with such visits nor correc-

    tion for matters of equity. Wnhere such benefit exists, the social

    optima occurs where the level of subsidization is equal to social

    benefit thereby internalizing this effect.

         In the case of beach usage,  however, significant social costs may

    also occur as noted in the previous section and must be incorporated in

    the decision-making process.  Beyond some point or threshold, social

    costs appear to increase at an increasing rate as environmental carrying

    capacities are taxed. Therefore, if rMC1 represents full pecuniary cost

    (including contributions from taxpayers), MC3 reflects both pecuniary and

    environmental cost and is upward sloping. Ignoring for the moment the

    fact that social benefit may also occur, the social optima is achieved

    at use level U3, and the value (and cost) of the last visit is equal to

    V3. Even with the inclusion of social benefit denoted by a paralleled shift

    of the benefit line to MB , MC3> MB , i.e., cost may exceed benefit for

    the last units consumed implying an overutilization of the resource.

    At high levels of utilization, this result is likely, in fact, as mar-

    ginal cost is increasing due to environmental effects and marginal

    benefit is decreasing due to saturation.

         To solve this dilemma a number of environmental groups and public

    officials are calling for tighter controls on use, the removal of sub-

                    1~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 57

              sidy programs, and the public acquisition of undeveloped areas. Each of

    I        ~~these positions represent an appropriate component of coastal policy and

    3        ~~will be addressed in turn.  Many of the proposals that have been made,

             however, reflect a strong conservationist sentiment. Although selective

    5        ~~conservation is appropriate to assure variety of opportunity at a later

             date and to prevent beach areas from exceeding their carrying capacity,

    I        ~~access to the beach resources through both public and private means must

    3        ~~also be assured to meet demands for such recreation in the coming years.

             Despite a leveling of population growth and a slower rate of economic

    5        ~~growth projected for the coming decade, the fact that greater numbers of

             individuals have been exposed to oceanfront experiences over the last

    I        ~~generation will assure a continued and growing demand for such activity.

    5        ~~The denial of sufficient access will preclude the potential for signi-

              ficant social gain. Closer attention must be given then to methods of

    5        ~~reducing the social cost of development and of internalizing as many of

             the remaining costs as possible to encourage responsible actions by

    I        ~~individuals.  The primary costs of development that must be addressed

    �        ~~include costs stemming from:

                        1) spillover effects,

                        2) information, and

                        3) risk

     I            ~~~~Because the coastal ecosystem is so closely interrelated, imbalances

             that arise are likely to have spillover effects, i.e., repercussions

              throughout the system. Where two or more noncompatible activities occur

    3        ~~and the potential for compensation exists, such options should be con-

              sidered. For example, suppose that individual A builds a seawall or other

              form of erosion control structure which it is known will have a detri-

    3        ~~mental effect on neighbor B.  if B is sufficiently compensated for his/

              her expected loss of property, both parties are potential gainers. If

    3        ~~B suffers greater than expected losses requiring the construction of

    g        ~~further seawalls, the leapfrogging effect that often occurs with the use

              of seawalls might evolve. Were this loss accruing only to private pro-

    3 ~~pert)', effective solutions still might be achieved. Risk and uncertainty

              would soon be incorporated such that at some point the cost of compen-

    3        ~~sation exceeded personal property loss and the seawall would no longer

              be extended. Yet, the extent of damage to the public beach also must

              be considered, and the appropriate compensation to the public in terms

    3        ~~of taxes and fees would likely be prohibitive given the use value of

              the beach and the community-wide effects that might be induced from this

    3        ~~initial action.

                   Where spillover effects are community-wide in their impact and not

              amenable to compensation, solutions must be community-wide in scope.
    3        ~~Activities falling under this category generally involve either overuse

              of the natural (or social) carrying capacity or alterations of the

    3        ~~natural system which, in turn, impact others.   In terms of erosion

              control, alterations of the beach and dune system or to sand transport

    I        ~~may significantly affect beach formation and subsequent erosion rates

    3        ~~within an entire beach reach.  It is appropriate to develop erosion

              control measures as static land-use patterns prove inadequate.

     3            ~~~~Compa tible development along the oceanfront requires that structures

                    1                                                        ~~~~~~~~~~~~~~~~~~~~59

            conform to the natural environment as presently configured as well as to

            the expected beach configuration over the useful lifetime of the building.

    3      ~~The useful lifetime of the structure may vary depending on its purpose

            and construction. Typical housing mortgages run for 30 years, although

    3       ~~a 50 year planning horizon might be a more reasonable target to reflect

            a longer life expectancy and to allow a buffer in the event of antici-

            pated rapid erosion.

     5          ~~~Where development does not accommodate changes in beach formation,

            the potential for property damage is greatly increased. Although

    3      ~~patterns are by no means consistent and many areas are presently accreting,

            the domirnant trend along the Atlantic and other ocean coasts has been one

    I       ~~of gradual long-term recession.   In additio-n, and perhaps more sig-

    3 ~~nificant in terms of property loss, there has been short-term erosion caused

            by ocean storms or by changes in sand transport patterns, be they

    3       ~~natural or man-made changes.  Where shoreline migration is allowed to run

            its course, dune and beach systems often are stabilized considerably

    I       ~~seaward of their inland penetration.  Erosion control structures and

    3 ~~building foundations, on the other hand, often prevent natural adjust-

            ment processes, lending instability to the imme~diate beach system.

    3       ~~Furthermore, threatened homes and commercial establishments encourage

            the use of structural solutions which may provide immediate relief but

    I    ~     ~which may also contribute to long-term erosion inflicting cost on

    3       ~~the owner and neighboring property owners.  Internalization of these

            costs require either a method of private compensation or of land use

    3       ~~controls restricting use -of l1ong-term erosion control structures

            .or of discouraging unwise building patterns. The latter of

                    1                                                        .~~~~~~~~~~~~~~~~~~~60

             these two options is the less costly long-term solution as property is

    I       ~~removed from potential hazard areas.

     3          ~~~A number of states and communities have instituted coastal setback

             laws either precluding or requiring a variance for location seaward

    3       ~~of the line.  Criteria employed include but are not limited to:  flood

            maps and storm history, past erosion rates, site specific observation,

    I       ~~or some combination of the above.  The legal foundations for such laws

    3 ~~are the police power of the state while their general intent is to

            protect the health, safety, morals and general welfare of the community.

     3           ~~~Present property owners i.e., those having structures in place, are

             generally exempt from such provisionshaving built under earlier instit-

    I ~~utional arrangements. New construction must be treated in a universal

    3 ~~fashion to prevent or minimize the loss of view which often encourages

            building at the front of waterfront lots. Additionally, the alleviating

    3 ~~of potential loss also alleviates the need for short-term 'bandaid'

             solutions which may have detrimental long-run effects.

     I           ~~~The taking issue associated with zoning law is discussed in greater

    3 ~~detail in Chapter V. In general, the courts have maintained that

            set-back laws do not constitute a taking. Yet, where reasonable use of

    3 ~~the land is precluded, public acquisition should be an available option.

            The loss of private discretion through land-use control is balanced

    I ~~against the public interest. Because of the fragile nature of the

    3       ~~coastal system in terms of both physical and biological resources,  in-

            dividual actions may be community-wide in their effect. Optimal sol-

    3       ~~utions require that external costs be internalized where possible;

                    3                                                          ~~~~~~~~~~~~~~~~~~~~~61

              where they cannot be internalized, potential social costs should be

    3        ~~minimized where doing so does not seriously restrict private property rights.

                   The second peculiar cost associated with coastal development cited

    I        ~~previously is the cost of information.  The science of coastal geo-

              morphology is most complex. With the number of variables influencing

              beach formation, extensive research activities are often necessary to

    3        ~~explain coastal processes influencing long and short-term shoreline

              patterns. As such, an understanding and appreciation of these processes

    3        ~~is generally lacking among potential buyers.  It is, therefore, In tA.

              public interest to disseminate information to both individuals and to

              local communities through technical assistance programs. In addition,

    3        ~~although setback provisions are restrictive, they serve as a line of

              demarcation and information system indicating high hazard potential.

    3         ~~Individuals, based on this information, are allowed then to build at

    *        ~~or beyond the setback line depending upon their aversion to risk.

                   With the last point having been made, we come to the final

    3        ~~identified cost that must be incorporated to assure proper resource

              utilization. Because the oceanfront is a hazardous area, the risk

    3        ~~associated with location in such areas is substantial.  Still  public

              policy has effectively minimized risk through programs such as

              Federal Flood Insurance and Disaster Relief. As a result, individuals

    U        ~~often undervalue the potential loss of building in hazard areas while

              significant federal and private insurance payments are required to

    3         ~~correct for this situation.  Unlike the spillover costs discussed pre-

              viously, risk can be internalized, i.e. borne by the property owner,

    U         ~~given adequate information.  More effective use of coastal resources can

    3        ~~be obtained where private property owners incorporate the full cost of

                     3                                                         ~~~~~~~~~~~~~~~~~~~~~62

    U        ~~development into their decision-miaking process.  The public sector

    3        ~~in turn, should provide a frame~work which corrects and/or minimizes

              social costs and provides information. At the same time,, the frame-

    I        ~~work should encourage individuals in making personal decisions to

    3        ~~pursue objectives consistent with stated public policy.

                                                                   63

                                    FOOTNOTES

         1.  U. S. Department of Commerce, Bureau of the Census, 1970 Cen-
    sus of Population Washington, DC: Government Printing Office, with
    updated estimates to 1976.

         2.  Final Evaluation of Stormwater Runoff Control Alternatives for
    the Myrtle Beach Stormwater Study submitted to Waccamaw Regional Planning
    and Development Council by Moore, Gardener and Associates, Inc., Consult-
    ing Engineers, Surfside Beach, S. C., March, 1980.

         3. The Hilton Head Island Chamber of Commerce, Based on estimates
    by Donald Hobart, Sea Pines Plantation, Hilton Head Island, S. C., 1979.

         4. Office of the Building Inspector, Beaufort County Joint Planning
    Commission, "Building Permit Totals on Hilton Head Island from 1952 thru
    1979." The Hilton Head Island Chamber of Commerce, January 1,. 1980.

         5. Observation of Neil Frank, Director of the National Hurrincane
    Center in MacLeish (1980).

         6. U. S. Department of Commerce Bureau of Economic Analysis, Sta-
    tistical Abstract, Washington, D. C.:  Government Printing Office, 1979.

         7. U. S. Department of Labor, Bureau of Labor Statistics, Employ-
    ment and Earnings States and Areas, 1939-75, Washington, D. C.:
    Government Printing Office, 1977.

         8. Rutherford H. Platt, "Coastal Hazards and National Policy: A
    Jury-Rig Approach," Journal of the American Institute of Planners,
    April, 1978.

         9.  South Carolina Department of Parks, Recreation and Tourism, 1979
    South Carolina Recreation Participation and Preference Study.

         10.  U. S. Department of Interior, Office of Heritage Conservation
    and Recreation Service, Report of the Barrier Island Work Group, (Decem-
    ber 18, 1978), p. 65.

         11.  Ibid., p. 74.

         12.  Ibid.

         13. South Carolina Department of Parks, Recreation, and Tourism,
    The Dynamic Impact of Tourism and Travel on the Economy of South Carolina,
    Columbia, S. C., 1978.

         14. South Carolina Department of Parks, Recreation, and Tourism,
    ibid. Much of Charleston's tourism is admittedly not tourism related.
    Nevertheless, the dominance of these coastal communities to the state's
    tourism industry seems obvious.

                    *                                                            .~~~~~~~~~~~~~~~~~~~64

     1            ~~~15.  Estimates taken from samples of beachfront and second row lots
             at Myrtle Beach based upon the 1979 Horry County Tax Assessment.
     1            ~~~16.  Once development occurs with spinoff activities, the direct
             effect of the beach may become less important. Restaurants, nightclubs,
             and golf courses may become, to some individuals, as important in attract-
             ing visitors. Nonetheless., the initial and predominant caused effect

    I~~~emscer

                                                                  65

                                 BIBLIOGRAPHY

    Brewster, Lawrence Fay. Summer Migrations and Resorts of South Carolina
        Low-Country Planters. Durhan, North Carolina: Duke University
        Press, 1947.

    Clark, John. Barrier Islands and Beaches - Technical Proceedings of
         the Barrier Island Workshop, The Conservation Foundation, 1976,
        p. 47.

    Crayden, Nell S. Tales of Edisto. Columbia, South Carolina:
        R. L. Bryan Co., 1955.

    Devereaux, Anthony Z. The Rice Princes. Columbia, South Carolina:
        The State Printing Co., 1973.

    Ellerbrock, Michael J. and James C. Hite. "Factors Affecting Regional
         Employment and Tourism in the United States." Journal of Travel
         Research 18 (Winter 1980): 26-32.

    Krutilla, John V. "Conservation Reconsidered."
        American Economic Review, 1967, pp. 777-786.

    Leatherman, Stephen P., Paul J. Godfrey and P. A. Buckley. "Management
         Strategies for National Seashores." Reprinted from the proceedings
         of the Symposium on Technical, Environmental, Socioeconomic and
         Regulatory Aspects of Coastal Zone Planning and Management, San
         Francisco, California, March 14-16, 1978.
    MacLeish, William H. "Our Barrier Islands are the Key Issue in 1980,
         the'Year of the Coast'.0" Smithsonian, September, 1980, pp. 47-59.

    Marshall, Harold E.   Efficiency Impacts of Cost Sharing on Shoreline
         Management." Coastal Zone Management Journal 2 (1976): 369-381.

    Moore, Gardner and Associates, Inc.  "Myrtle Beach Stormwater Study."
         March, 1980. (Mimeographed)

    Platt, Rutherford H.  "Coastal Hazards and National Policy:  A Jury
         Rig Approach." Journal of the American Institute of Planners 44
         (April 1978): 170-180.

    Prevost, Charlotte K. and Effie Leland Wilder.  Pawlley's Island, a Living
         Legend. Columbia, South Carolina: The State Printing Co., 1972.

                                                                 66

    Sorenson, John H. and Mitchell J. Kenneth. "Coastal Erosion Hazard in
         the United States: A Research Assessment. Institute of Behavioral
         Schience, The University of Colorado Program on Technology, Environment
         and Man.

    Tanner, William F. "Our Moving Beaches." Americas 23 (October 1971):
         2-8.

    U. S. Department of the Interior. Office of Heritage Conservation and
         Recreation Service. Report of the Barrier Island Work Group.

            I                                 ~~~~~~~~~~CHAPTER V

        3                      ~~~~~~~PUBLIC POLICY TOWARD EROSION CONTROL

     3           ~~~Because the negative effects associated with coastal development

             have intensified only in the last century, public policy in this regard

             evolved slowly with programs generally instituted in piecemeal fashion.

             Recently, however, policy makers at all levels of government have begun

    I        ~~to reevaluate existing programs and to seek more effective measures of

    3       ~~control for natural hazards.  The following chapter will examine the

             existing institutional framework at the federal, state, and local level

             and explore a variety of policy options being considered.

                                          Federal Policy

     I           ~~~Federal responsibility for erosion control traditionally has been

    3       ~~that of the U. S. Army Corps of Engineers.  Present federal policy in

             this regard has been shaped largely through -passage in succession of

    3       ~~the Federal Flood Insurance Act (1968), the National Environmental Policy

             Act (1969) and the Coastal Zone Management Act (1972). Proposed Barrier

    *       ~~Island Legislation in Congress has been delayed but may in its present

    3       ~~or altered form significantly impact federal policy along the coast.

             The Corps of Engineers

     3           ~~~The Corps' powers with regard to erosion control were broadly inter-

             preted from Congress' initial authorization of navigation improvement

    I       ~~projects in 1824.  The scope of Corps projects broadened over time in-

             cluding specific authorization for shore protection projects in 1946.

             Although major attention in the past has been given to engineering crite-

    3 ~~ria, the Corps has begun in recent years to incorporate a more

             sophisticated management approach including a committment "that the social

                    3                                                        ~~~~~~~~~~~~~~~~~~~~68

            consequences of contemplated water resource development actions be con-

    3 ~~sidered and taken into account during the planning process."'

                 The Corps is presently involved in a number of beach protection/

    I ~~restoration projects. These projects are restricted by law to the resto-

            ration of beaches to their historic limits, i.e. new beach areas are

            specifically forbidden. As with all such federal programs, all beaches

    3      ~~receiving erosion control benefit from federal projects must be open to

            use by the public. Projects providing hurricane protection are exempt

    I      ~~from this requirement, although multiple-purpose hurricane protection

    3 ~~and beach control projects may justify further federal support.

            The Federal Flood Insurance Program

     3          ~~~The Federal Flood Insurance Program is administered by the Federal

            Insurance Administration (FIA). The goals of the program are "to encou-

    I ~~rage state and local governments to make appropriate land use adjustments

    3      ~~to constrict the development of land which is exposed to flood damage and

            minimize damage caused by flood losses." and "to . . . . guide the deve-

    3      ~~lopment of proposed future construction, where practicable, away from

            locations which are threatened by flood hazards."  2As noted in an ear-

    I       h~ler section, neither of these goals appears to be met at the present

    3 ~~time.

                 In part, because of concern over the effectiveness of the program,

    3 ~~the Federal Insurance Administration was transferred to the Federal

            Emergency Management Agency (FEMA) by Executive Order 12127 on April 1,

    I ~~1979. Still, FIA retains its identity as an agency within FEMA. In-

            ternal review of the program is currently being conducted and

           reauthorization of the Agency before the next session of Congress will

    3      ~~provide a significant gauge of Congressional attitudes and future

                    *                                                          ~~~~~~~~~~~~~~~~~~~~69

    U        ~~federal policy.  At question is the role of the federal government in

             sharing the risk associated with coastal development.

    I        ~~The Coastal Zone Management Program

                  The Coastal Zone Management Act of 1972 (CZMA) represents a state-

             ment of need and desire to provide wise management of the nation's

             resources. The Act includes provisions for coordination of federal and

             state activities in the coastal zone. To do so, it employs incentives

    I        ~~for states to develop comprehensive management programs; federal fund-

    3        ~~ing is provided to develop and implement programs which meet standards

             established by the Secretary of Commerce. Provisions for federal/state

    3        ~~consistency are included in the Act which states that:

                        1) each federal agency conducting or supporting activi-
                            ties in a manner which is to the maximum extent
                            practicable, consistent with approved state manage-
       5                   ~~~~~~ment plans,    (Section 307(c)(1)), and

                        2) federal agencies shall not approve proposed projects
       3                   ~~~~~~that are inconsistent with the coastal state's manage-
                            ment program, except upon a finding by the Secretary
       3                   ~~~~~~that such a project is consistent with the purposes
                            of this title or necessary in the interest of national
       3                   ~~~~~~security.  (Section 307(d)).

                  The 1976 Amendment to CZMA includes more specific language with re-

    3 ~~gard to shoreline erosion/mitigation planning. Section 305(b) (a)

             -mandates that:

      I               ~~~~~the management program for each coastal state include ...
                       a planning process for A) assessing the effects of shore-
      5                ~~~~~line erosion (however caused), and B)  studying and
                       evaluating ways to control, or lessen the impact of, such
      3                ~~~~~erosion, and to restore areas adversely affected by such
                       erosion. (Federal Register 923.25).

                    *                                                         ~~~~~~~~~~~~~~~~~~~~~70

     I            ~~~~Provisions of the Amendment addressing erosion control are included

    3        ~~in Appendix A.  The program must include a method for assessing the

             effects of shoreline erosion and of techniques for controlling this

              erosion. It must also identify and describe "enforceable policies, legal

             authorities, and funding techniques" to be used in erosion management

    I        ~~(Section 305(c)(2)). As such, the CZMA provides the framework for state

    3        ~~and federal committment relating to erosion control and management.

             New Directions in Federal Policy

     3            ~~~~In his Environmental Protection Message of May 23, 1977, President

             Carter outlined policy with respect to barrier islands indicating that:

      I~~~~~~ .   . barrier islands are a fragile buffer between wetlands
                        and the sea . . . Many of them are unstable and not suited
      I                ~~~~~for development, yet in the past the Federal Government
                        has subsidized and insured new construction on them.
      3                ~~~~~Eventually, we can expect heavy economic losses from this
                        shortsighted policy.

     3            ~~~The designation of 1980 as the Year of the Coast is symbolic of a new

             awareness of the importance and fragility of the coastal ecosystem. Per-

    I        ~~haps more importantly, the introduction of Barrier Island Legislation in

    3        ~~both houses of Congress reflects a clear departure from past federal poli-

             cies. The House Bill (HR 5981) introduced by Rep. Phillip Burton (D.

    3        ~~Calif.) would provide for federal protection of undeveloped barrier is-

              lands. The legislation would empower the Secretary of the Interior to

    *        ~~acquire undeveloped islands or undeveloped portions of developed islands

    3        ~~and place them in a National Barrier Islands Park System.  The bill would

             further prohibit federal assistance on undeveloped islands for roads, air-

    3        ~~ports, erosion control projects and reconstruction of privately owned

             buildings after natural disasters. A grandfather clause would exclude

                    I                                                         ~~~~~~~~~~~~~~~~~~~~~~71

            existing development.

                 Of some 300 barrier islands, 184 will be wholly or partly included

            within the map of "Barrier Island Units of the National Park System.",3

    I       ~~A major criticism of the bill has been the failure of sponsors to pro-

    *       ~~duce a cost estimate for acquisitions in a time of fiscal conservancy.

            Proponents argue that the total cost of acquisition will be substan-

            tially less than will be expended for development and hazard mitigation

            based on present trends. In Congressional testimony, Crane Miller, an

    I      ~~outspoken advocate of the concept, estimated that "the cost of land

            acquisition authorized by the bill is conservatively estimated to be

            less than one-fifth of the federal costs for access, infrastructure,

            and disaster relief than if the same islands were developed to less than

            half their potential (44%).,,4 Purchase of undeveloped sections of

    I      ~~previously developed islands would considerably raise the cost, and no

            concensus has been reached as to the appropriate price to be paid pro-

            perty owners. In addition, no estimates of loss from removing these

            lands from extensive use or of providing public access for 'optimal' use

            have been made. Still, the realization that lands can be purchased by

    I      ~~the federal government for less than is being paid in terms of subsidi-

            zation for intensive development is a sobering indictment of past

            federal policy.

                 The Senate Bill (S. 2686) sponsored by Senator Bumpers (D. Ark.)

            does not provide for acquisition. Like the Burton Bill, it does forbid

            the use of federal subsidies for islands comprising the "Barrier Islands

            Protection System." The bill additionally establishes a Barrier Islands

    U      ~~Advisory Council to be chaired by the Secretary of the Interior and to

                    *                                                        ~~~~~~~~~~~~~~~~~~~~~~72

    I      ~~include representatives of 15 federal departments or agencies.  The

            functions of the Council would be to provide for coordination and con-

            sultation among agencies to assure a consistent federal policy with

            regard to barrier islands and to study and make recommendations with

            respect to regulation and management plans.

     I          ~~~The thrust of the two bills reflects a strong yet rigid committment

            to conservation. Little attention is paid to the wise use of currently

            developed beaches nor to making undeveloped lands available for use in

            either a public or private framework. In addition, control is vested

            at the federal level rather than at the state level as designed under

    U      ~~the Coastal Zone Management Act.  It seems obvious that a greater

            federal committment is necessary as state consistency review is politi-

            cally difficult in the face of lucrative federal programs which may

            conflict with state coastal programs. Until a federal conscensus is

            achieved, states, whether they wish to or not, will be required to

    I      ~~assume major responsibility with respect to beach management.  It is to

            the role of the state that we now turn.

                                           State Policy

                 Coastal policy in many states has been clouded historically by legal

            questions as to tidelands ownership, i.e. with regard to lands lying be-

    I ~~low or seaward of mean high water. Major attention to the issue of

    *      ~~coastal erosion control has evolved over the past decade with the primary

            catalyst being the Coastal Zone Management Act of 1972. Prior to this

            time, some attention was given to dune protection, and broad guidelines

            were drawn with regard to engineering works, yet legislation pertaining

    I      ~~to coastal conservation and resource management was sparse.

            Policies Employed by Other Coastal States

                 In 1970, Florida passed a statewide construction setback law requir-

            ing that any construction on excavation must be at least 50 feet upland

    I      ~~of mean high water.  The following year a second piece of legislation ex-

    j ~~tablishe d a basis for the Coastal Construction Control Line to remedy

            inadequacies and problems of enforcement with the earlier act. The pri-

    *      ~~mary emphasis of the law is that area seaward of the construction

            control line should not be disturbed nor constructed upon. In itsdefense,

    U      ~~the act explains that "establishment of a control line does not preclude

            reasonable use of coastal property .. ."1  (16 B - 33. 05).

                 A permit system was established to provide variances where "reason-

            able" exceptions are warranted. Applicants must prove that the

            exemption is reasonable before a Review Board or the Executive Director

    I       ~~of the Department of Natural Resources.  In no cases, however, shall the

            Department "contravene setback requirements on zoning or building codes

            established by a county or a municipality which are equal to, or more

            stringent than, the requirements provided herein." (16 B - 33.06).

            Seven counties, some islands and several keys were made exempt from the

    I       ~~permit requirements of the act.

                 Since 1972, a number of other states have developed or proposed

            programs. In Hawaii, the Shoreline Setback Law prohibits development

            within 40 feet of the shoreline; while in the Territory of Guam, the

            Seashore Protection Act strictly limits construction within 10 meters

    I       ~~of the shore.  The Texas Setback Law designates critical dune areas and

            provides a basis for local governments to establish setbacks. North

            Carolina's Coastal Zone Management Law identifies "Ocean Hazard Areas"

                    *                                                        ~~~~~~~~~~~~~~~~~~~~~74

           as beaches, frontal dunes, inlet lands, and any other areas subject to

           excessive erosion flood damage. The boundaries for the areas fall be-

           tween mean low water and the extent of shore which is subject to

    �      ~~erosion or change in the next 50 years (Section .0300).  Still more

           recently, ambitious programs have been proposed in Alabama, and the New

           Jersey Plan is the most elaborately developed to date including a single.

    I      ~Special Area Policy (7:  7E-3.19) relating to beaches, high risk erosion

           areas, overwash areas, and dunes. Although New Jersey has had an

    I      ~~erosion planning process in place for a number of years, the primary

    *      ~~statutory basis for the present Shore Protection Master Plan is the

           1977 Beach and Harbor Bond Issue.

                Increasingly, states have indicated a preference for non-structural

           solutions including regulatory and management provisions. The extent

    U      ~~and manner of implementation of coastal land-use restrictions vary by

    5 ~~state. Programs in Rhode Island and New Jersey, for example, represent

           examples of strong state-level administration, while in California, the

    j ~~state and the Regional Coastal Commissions permit development in erosion

           as well as earthquake-prone areas. Maryland encourages localities to

    I ~~establish erosion control districts with programs meeting state guide-

    I ~~lines; state funding is used as leverage. Similarly, Washington State

           mandates local jurisdictions to prepare "Master Programs" which may

    5 ~~address a variety of options including shoreline setbacks.

           Policy in South Carolina

     I          ~~~Erosion control policy for the State of South Carolina is identified

            in the State Coastal Management Act of 1977. The act designates the

            South Carolina Coastal Council as the responsible party for management

                    1                                                          ~~~~~~~~~~~~~~~~~~~~~~75

    I        ~~and regulatory activities in the coastal zone.  A regulatory program was

              established "for the purpose of promoting the public health, safety and

              welfare, and the protection of public and private property from beach

              and shore destruction. " It provides for permit authority within cri-

              tial areas, i.e. seaward from the trough behind the primary dune line. In

    I        ~~addition, Council is granted responsibility to develop and implement a

              comprehensive beach erosion control program and permit jurisdiction over

              erosion control and water drainage structures not otherwise covered by

    5        ~~the law.6  Council is also designated as the authority to accept federal

              monies and to administer state monies allocated for erosion control.

     I            ~~~The South Carolina Coastal Management Program (SCCMP) was approved

              in 1979. The program states a preference for non-structural solutions

              where possible, employing the natural sand deposits and flood protection

    5        ~~of dune systems.  It is further stated that dunes should be protected

              and preserved and that buffer areas should be established where possible

    5        ~~to allow for their "natural movement and growth."

                   The SCCMP identifies considerations that must be addressed before

              erosion control projects can be approved (Section IV C(4)(b)). These

    *        ~~items include:

                        1) The type of materials employed, their useful life ex-
       *                   ~~~~~~pectancy along with anticipated maintenance and
                            replacement costs;

      *                ~~~~~2)  Rate of rise or fall of sea level at the location;

                        3) Sediment transport and sand budget in the project
       if                  ~~~~~~area;

                        4) The economic justification of the proposed project
       5                   ~~~~~~in comparison with available erosion control alter-
                            natives including consideration of the anticipated
       5                    ~~~~~~damage and economic loss due to failure;

                    1                                                        ~~~~~~~~~~~~~~~~~~~~~76

                       5) Extent of up or downdrift damage due to install-
       3                  ~~~~~ation or lack of installation of the erosion

                           control structure;

      �               ~~~~6)  The extent to which the project fits into a comprehen-
                           sive shore protection program for that particular
                           stretch of beach, aimed at preserving the beach pro-

                           file in its present slope and configuration.
    3       ~~In addition, the policy of Council with regard to specific erosion con-

            trol activities is identified in Section IV C(4)(c) which is included

    5       ~~as Appendix B.  A revised plan entitled Specific Project Standards for

            Beaches and Dunes has been drafted but has not been approved as of this

    I       ~~writing.  The plan includes similar language to that contained in the

            previously cited Erosion Control Policies (Section IV C (4)(c). In

            addition, evaluation criteria are specified including: 1) the require-

    3       ~~ment that the best available data on sediment and sand budget A (1) (a),

            2) the preference for natural features as opposed to artificial pro-

    I       ~~tection A (1) (b), and 3)  requirements that public access be assured

    3 ~~and protected if state monies are committed. Similar provisions are con-

            tained in the SCCMP under Funding Policies (IV C(4)(a)) and General

            Considerations (IV C(4)(b)).

                 The inclusion of state policy and funding considerations as a pre-

    I ~~face to the design considerations outlined is appropriate. If the intent

            of the standards is to incorporate state policy on erosion abatement in-

            cluding funding provisions, the policy should be stated more clearly.

    5       ~~Included should be a clear identification of the state's long-run policy

            with respect to erosion control. The wording might state that the pri-

    I ~~mary aim of the state is to provide for maximize enjoyment of the state's

    I ~~beaches in a manner consistent and not in opposition to coastal processes.

                    1~~~~~~~~~~~~~~~~~~~~~~7

    I       ~~Although included in the SCCMP, the revised standards do not require that

             the project be economically justified from the state's perspective before

             state monies are expended, and no requirement is made that the best

             available data and methodology be employed it balancing in accessing the

             economic feasibility of the project. Further discussion of funding ar-

    I        ~~rangements is reserved for a later section.

     3           ~~~Finally, to assure consistency with state programs, it is recommended

             in the State Management Plan (SCCMP IV - 59):

      5               ~~~~1)  The Council recommends that local governments in shore-
                           line areas institute shorefront construction setback
       I                  ~~~~~lines as part of their land-planning activities and/or
                           local building codes, subdivision regulations, or zon-
       u                  ~~~~~~ing ordinances.

                       2) Private property owners and developers are encouraged
                           to consult with the Council or with technical consul-

                           tants to learn the erosion trends and shoreline
                           dynamics in their particular area before initiating

                           construction.
    3       ~~The incorporation of local entities into the management plan is the sub-

             ject of the following section.

            3                               ~~~~~~~~~~Local Policy

                  Effective management to lessen the damages inflicted by coastal

    I       ~~hazards requires active involvement of local jurisdictions.  The intent

             of Federal and State Coastal Zone Management Programs has been to dele-

             gate as much authority as possible to coastal communities under the

    3       ~~assumption that local government can achieve maximum responsiveness to

             local conditions, better accountability, and greater public accessibility.

    *      ~~The actual level of involvement is largely subject to state and local

             discretion as incorporated in state management plans or amendments thereto.

                    1                                                          ~~~~~~~~~~~~~~~~~~~~~78

     I           ~~~The California Coastal Program provides a particularly active role

             for local governments. Each local government in the coastal zone (15

             counties and 53 cities) prepares a Local Coastal Program. Programs may

    5       ~~be prepared by either the local government or the State Coastal Commis-

             sion although preference is given to the former entity to allow local

    j        ~~interests to dictate policy as long as the guidelines of the state pro-

             gram are met. Regional commissions also participate in a review and

             advisory capacity.

     �           ~~~The State of Washington is continuing to enhance the role of local

             governments in the areas of program administration and enforcement.

    I      ~ ~Local malsters programs are currently being revised and refined.  Other

             states including Oregon, Maryland, and North Carolina require local

             governments to prepare local management plans in order to participate in
    3       ~~all or specific areas of the state program.  In Alaska, district programs

             have been developed; while in Florida, regional planning councils play an

    5       ~~active role.

                  The South Carolina Coastal Management Program provides a basis for

             local involvement, and the State Coastal Council provides technical sup-
    3       ~~port to local governments in developing either specific or comprehensive

             programs. Yet, as the South Carolina Program is relatively new by

    5 ~~national standards, the extent of local program development remains

             limited at this uniting. Particularly with respect to erosion control

    5 ~~the development of local programs should be strongly encouraged. Not

    5       ~~only can it be argued that local interests by right should have the

             greatest input in the structure of community identity, but, as in most

    I       ~~states, land-use in South Carolina controls  are vested at the local level.

                    1~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 79

                  Through enabling legislation, local jurisdictions in South Carolina

    I        ~~are delegated the police power to zone ( 47 -1001 et. and more recently

               .14 - 350. 16 et. seg). As the critical region for state jurisdiction

    I        ~~extends, at most, only to the trough of the primary dune and with respect

    5        ~~to erosion control structures affecting public interest, for it is appro-

             priate for local governing bodies to supplement state permitting

    I        ~~activities as a means of limiting spill overs effects along the beach-

              front. To date, Beaufort County has introduced the notion of Beach

    I        ~~Development Districts, while the City of Myrtle Beach and Town of Folly

    5        ~~Beach are drafting programs at this time.

                   On September 11, 1978, Beaufort County adopted a Development Standards

    I        ~~Ordinance.  In addition to the standard purposes of a zoning ordinance, the
              intent of the Beaufort Ordinance is "to preserve the environmental, his-

    5        ~~torical, and social heritage and character of Beaufort County . . .1

              (Art. 1). The ordinance as is the current trend in land-use planning,

    �        ~~establishes special districts relating to:

      *                ~~~~~1)  Conservation,
                        2) Beach Development, and
      5                ~~~~~3)  Flood Hazard

                  More specifically, with respect to beach areas, the ordinance pro-

    5        ~~tects sand dunes and dune vegetation (4. 3. 2. 1 and S. 3. 2. 4).  Public

              access to the beaches is guaranteed and must be provided using elevated

    I        ~~walkways (4. 3. 2. 2).  In addition, "Public beach access shall be pro-

    I        ~~vided by the developer for any development including more than one-
              thousand (1,000) feet of beach frontage . . . 1 (S. 3. 2. 2).

                    1                                                          ~~~~~~~~~~~~~~~~~~~~~80

                   Later, the ordinance reads: "No development shall be undertaken

    5        ~~that directly or indirectly increases the erosion of land or its potential

              for erosion" (S. 2. 7). Perhaps the most significant provision reads:

    I        ~~"No structure will be constructed within 75 feet landward of mean high

              water or 40 feet landward of the crest of the primary dune except for

             beach pavilions of less than 400 square feet elevated with pilings; beach

    5        ~~boardwalks or structures whose specific purpose is to protect or improve

              the beach and dune." (S. 3. 2. 4). This section outlines the guidelines

    I        ~~for a beach setback line, the principle details of which are included in

              deeds for beachfront property as covenants or deed restrictions. Reason-

              able variances are provided, and, in general, permits are issued on an

    I        ~~administrative rather than a quasi-judicial basis.

                   Local ordinanaces of this type are consistent with state policy and

    5        ~~provide a framework for more effectively managing development in erosion

              prone areas. Where possible, setback lines should incorporate scientific

              information to allow for highly erosional zones along the beachfront or in

    5        ~~inlet areas which may display volatile rates of erosion.  In addition,

             particular care should be taken to assure that loopholes to development

    3        ~~do not exist.  In the Beaufort Plan, for example, some question remains

             as to jurisdictional responsibility where maritime forests re-place the

             primary dune as the first landmark. Such a situation suggests that the
    5        ~~area is highly unstable and not an appropriate building site.

                   As state and local interests overlap with regard to erosion control, it

    5        ~~is appropriate that consistent policies be pursued.  Local and state per-

             mit authority may overlap with regard to dune management, erosion control

    I        ~~structures, and public access.  Land use authority beyond the primary dune

    line is currently the primary responsibility of local entities. For tech-

    nical reasons and perhaps more importantly to shelter local zoning boards,

    serious consideration should be given to state as well as local review of

    building setbacks along the oceanfront.  The initiative might be taken

    either locally or at the state level.  A further discussion of this arrange-

    ment is included in the following section and in the following chapter

    under legal considerations.

         The funding of coastal erosion control projects is a relatively new

    and complex process.  Public monies may be provided on a federal, state,

    or local level in accordance with certain policies and requirements as

    follows.

                             Funding Responsibility

         Public responsibility for funding erosion control projects rests

    collectively with federal, state, and local authorities.  Involvement and

    level of funding committment vary with the type, location, and impact of

    the project being considered. The following section summarizes funding

    criteria appropriate at each jurisdictional level.

    Federal Responsibility

        Under existing legislation, Congress has authorized the U. S. Army

    Corps of Engineers to conduct beach erosion control projects. Corps

    involvement is restricted to shores owned by the Federal Governnent,

    other public entities, or private entities when the shore is open to

    public use. The intent of this legislation is to prevent or control

    shore erosion caused by wind and tidal generated waves and currents along

    the coasts and shores. Such adverse effect extends only the distance up

    tributory streams where it can be demonstrated that the dominant causes

    of erosion are ocean tidal action and wind generated waves.  Federal

                    1                                                        ~~~~~~~~~~~~~~~~~~~~~82

             participation is limited to restoration of the historic shoreline.

     1           ~~~The determination of local cost is based on the public use and owner-

             ship of the beach protected. The federal participation cannot exceed one

    I       ~~million dollars.  Federal participation is 50 percent of the first cost

    I       ~~of protection of shores owned by non-federal public agencies, exclusive

             of land costs. Protection of certain shores not publicly owned may be

    5       ~~eligible for federal cost sharing up to 50 percent provided it can be

             shown that there would be significant public benefits arising from public

    I       ~~use or from direct protection of nearby public facilities.

     5           ~~~Under special conditions, beach erosion protection is eligible for

             federal cost sharing up to 70 percent of the total project cost, exclu-

             sive of land costs. In order for the maximum 70 percent federal participa-

             tion to be applied to parks and conservation areas, all of the following

    I       ~~criteria must be met to the satisfaction of the Corps:

     5            ~~~~(a)  The land must be publicly owned.

                   (b) The park must include a zone extending landward from
                        mean low water line which excludes all permanent human
                        habitation. This excludes summer residences but not
                        residences of park personnel and administrative
                        buildings.

     S             (~~~~c)  The park must include a beach suitable for recreational
                        use.

     5            ~~~~(d)  The park must provide for preservation, conservation
                        and development of the natural resources of the environ-
                        ment.

     �            ~~~~(e)  The park or conservative area must extend landward a suf-
                        ficient distance to include protective dunes, bluffs or
                        other natural features which will absorb and dissipate
                        wave energy and flooding effects of storm tides.
                   (f) Full park facilities must be provided for appropriate
                        public use.

                 No federal contribution toward project maintenance is authorized.

            However, federal participation may be made toward periodic beach-nourish-

    5       ~~ment when found to comprise a more suitable and economical re-medial measure

            for beach erosion control than other construction (U. S. Department. of the

    I       ~~Army, 1975.)

     5           ~~~Legislation does not specifically define federal interest in projects

            to protect against hurricane, abnormal tidal and flood damage. In accor-

    3       ~~dance with the President's proposed cost sharing policy, projects for

            Hurricane$ Tidal and Flood Protection require the local sponsor to con-

    I       ~~tribute 20 percent of the construction cost.  Previously this program

            also had a 70 percent federal share limit. Successful protection against

            hurricane and tidal flooding on the open coast frequently requires that

            the shoreline be concomitantly stabilized against erosion. For multiple-

            purpose hurricane protection and beach erosion control projects, Section

    1       ~~208 of the 1970 Flood Control Act provides discretionary power to the

    *       ~~Secretary of the Army to authorize a federal share up to 70 percent.

            (Massoni, 1980).

     5           ~~~Specific administrative rules on cost sharing can be promulgated by

            the Office of Management and Budget, the Water Resources Council and the

    3       ~~Secretary of the Army.  Before Congressional authorization of a Corps

            project, a District Engineer prepares a document with recommendations

            for federal involvement. Along with these recommendations, the District

    1 ~~Engineer will suggest a cost sharing ratio to the Congress through the

            Chief Engineer. This ratio can be changed at any point, prior to authoriza-

    3 ~~tion, but recommendations of the District Engineer are typically approved.

            -State Responsibility

     I           ~~~The Office of Coastal Zone Management requires participating states

                    1                                                         ~~~~~~~~~~~~~~~~~~~~84

             to include an erosion planning process in their coastal management programs.

             In the Federal Register, Vol. 44, No. 61, March, 1979, Section 923.25

             states that funding responsibility must be considered in their management

    I       ~~programs:

                       "There must be an identification and description of

                   enforceable policies, legal authorities, funding techniques

     3            ~~~~that will be used to manage the effects of erosion as the

                   state's planning process indicates is necessary."

     I           ~~~In 1977, the South Carolina Coastal Council was established as the

             responsible party for management and regulatory activities in the coastal

             zone. Included is the authority to accept federal monies and to administer

    if      ~state monies allocated for erosion control.  Decisions on funding beach

             erosion control must be based on careful reasoning and follow approved

    I       ~~funding policies at both the federal and state levels.  Section IV C(4)

             (a) of the South Carolina Coastal Management Program describes state

             funding policies:

                     1) Public funds can be expended for beach or shore erosion
                         control only in areas, communities., or on barrier islands
       3                ~~~~~to which the public has full and complete access (as defined
                         in the shoreline access segment of the program).

                     2) Public funds can be expended only for beach erosion control
       I              ~ ~~~~measures which are deemed by the Council to be consistent
                         with the Beach Erosion Control Policies in this section and
       �               ~ ~~~~any applicable rules and regulations promulgated pursuant

                         to the Act.
      t             ~~~~3)  Public funds can be expended only for erosion control measures
                         which are consistent with the overall coastal management
       I                ~~~~~program.

             *See Appendix

                   1                                                         ~~~~~~~~~~~~~~~~~~~~~85

                    4) Funding for particular erosion projects shall be approved
      5                 ~~~~~by the Coastal Council only after adequate consideration
                        has been given to the erosion control problems and needs
                        of each coastal county and the relative benefits of the

                        particular project.
                    5) Consideration will be given to the extent to which the

                        proposal will maximize the protection of public health,
                         safety, and welfare.

                    6) For expenditure of public funds, the full range of al-
                         ternative erosion control measures which are possible,

                         including no action, must be studied. Before decisions
                         are made, consideration must be given to the long and
      5                 ~~~~~short-range costs and benefits of the various alternatives.

                     7) Removal or modification of existing publicly-funded control
                         structures will be authorized by the Council based on the
                         applicable policies in this section and determination that
      3                 ~~~~~the structure has an adverse impact on the public interest,
                         as mandated by Section 12(_Q of the Act.

     3           ~~~Act 1377 of 1968 (State Capital Improvement Bonds). as amended in

            1978, provides $600,00.0 of state monies for beach. erosion or groin repair

            to be managed by the State Coastal Council. The Coastal Cou ncil may allo-

    3 ~~cate the funds provided that equitable consideration to the relative needs

            of the coastal counties is considered, provided that public access is maxi-

    3 ~~mized (no funding is allowed in any beach area not accessible to the public),

            and provided that consistency with federal funding is achieved.

                 At present, the state share is 90 percent of non-federal expenses,
    3 ~~with the remaining 10 percent of costs being met locally. The funding

            criteria as defined in Section IV C(4)(a) of the State Management Plan

    5 ~~must be met before funds are committed.

                                                                  86

    Local ResponSibility

         As erosion control projects are often expensive, communities may be

    strained to raise the local match even with the state meeting the majority

    of the non-federal share. Present enabling legislation allows munici-

    palities in South Carolina six options to raise local matching funds.

    Sources for these funds include:

            1)  property tax,

            2) licensing fees, franchise fees and fines,

            3)  user charges,

            4)  bonding (restricted largely to capital improvement projects),

            5) state shared revenue (e.g. beer and wine taxes and gasoline
                tax), and

            6) federal grants-in-aid.

         Although property taxes may offer the greatest potential revenue source

    at the municipal level, beach communities may have an inadequate tax base.

    Meanwhile, county-wide assessments may be inappropriate as the tax burden

    should rest more heavily on beach-front property.  User charges where

    collection costs are reasonable should be explored as a means of assessing

    costs of beach maintenance on beach users.  Public parking fees offer an

    appropriate source of such funds.

         Existing South Carolina legislation does not permit local sales or

    income taxes nor does it permit the adoption of an accommodations tax.

    However, a Local Option (one-half cent) Sales Tax Bill (S-2) has been

    prefiled with both the South Carolina State House and Senate for considera-

    tion during the 1981 session. As currently designed, if a local government

    opts for the local sales tax (municipalities may opt for this tax even if

    their county does not), 85 percent of the yield must be used to "roll back"

                    1                                                         ~~~~~~~~~~~~~~~~~~~~87

             local property taxes. The remaining 15. percent of the yield is discretionary

    1       ~~and could be used for local match.  The bill would provide for the use of

             more than 15 percent of the yield, however, if these funds are used for

    U       ~~bond reduction.

     I           ~~~A local options accommodations. tax is also being drafted and will be

             filed with the legislature early in 1981. It is the opinion of legislative

    3       ~~observers that the proposed bill will state that the proceeds from the

             accommodations tax must be spent on tourist related activities. Since

    I        ~~erosion abatement can probably be tied quite closely to tourism in most

    5       ~~of our coastal communities the passage of a local options accommodations

             tax bill could provide a major source of revenue for local match require-

    1        in~ents.  It is not anticipated that support for this bill will be as broad

             based as for the local options sales tax. Yet, both of these potential

    1        ~~revenue sources offer the advantage of shifting tax burden more appropriate-

    3        ~~ly to beach users to whom the greatest benefit accrues.

                                                                  88

                                   FOOTNOTES

         1.  United States Department of the Army, Office of the
    Chief of Engineers, "Digest of Water Resources Policies",
    January 1975.

         2. United States Constitution, Section 4002(e).

         3.  United States Department of the Interior, National Park
    Service, "Barrier Island Units of the National Park Service", 1980.
         4. H. Crane Miller, Testimony before the Committee on Interior
    and Insular Affairs, U. S. House of Representatives, March, 1980.

         5. United States Department of Commerce, Office of Coastal Zone
    Management, "State of South Carolina Coastal Management Program and
    Final Environmental Impact Statement", Section IV C (6), 1979, p. IV-60.

         6.  Ibid.

                                   CHAPTER VI

                              LEGAL CONSIDERATIONS

                Authority to Regulate Erosion Control Activities

         Regulatory authority over various methods of erosion control exists

    at all levels of government; federal, state, and local.  Federal authority

    derives from the commerce clause of the Constitution of the United States1

    which vests in Congress virtually complete power over all matters affect-

    ing interstate commerce.

         Congress has enacted several pieces of legislation2 dealing directly

    with erosion of ocean beaches.  First, the Federal Rivers and Harbors Act,3

    as modified by the Federal Water Pollution Control Act Amendments of 1972,4

    authorizes the U.S. Army Corps of Engineers to regulate any activity which

    affects the navigable capacity of waters of the United States. Erosion

    control structures, to the extent they affect navigation, are thus subject

    to regulation by the Corps.  Dealing more specifically with erosion of

    ocean beaches is the Federal Coastal Zone Management Act5 which expresses

    federal concern with the problem and directs the coastal states to address

    it in their coastal zone management plans.  As a practical matter then,

    Congress has left development and implementation of beach erosion policy

    largely to the coastal states.6

         State authority over beach erosion derives from two sources. The

    State of South Carolina, as is the case in many other coastal states,

    generally owns land seaward of the mean high tide line.7 Power thus

    exists to control any encroachment on state owned submerged land and waters,

    and construction of structures such as groins and seawalls is subject to

    regulation by the state.  In other areas. the general police power confers

                                                                  90

    broad Powers to control any activity affecting the public health. safety.

    and welfare.  Because of the obvious effect of beach erosion on property

    values. it is subject to state regulation.

         Based on these powers. the South Carolina General Assembly addressed

    the Problem of beach erosion. alone with other issues of coastal manage-

    ment. in the South Carolina Coastal Management Act of 1977.8  The

    legislation directs the Coastal Council to "develop and institute a com-

    prehensive beach erosion control policy"9 and empowers the Council to

    issue Dermits for erosion control structures "on or upon the tidelands

    and coastal waters"10 of the state and to remove "all erosion structures

    which have an adverse effect on the public interest".11  The statute thus

    establishes a permitting system for erosion control structures on state

    owned land or waters (tidelands and coastal waters) and asserts control

    over all existing structures. regardless of location. if their existence

    adversely affects the public interest. Regulation over erosion control

    structures not on state land or waters but in "critical areas" can be

    accomplished under the general permit provisions of the Act.12  Non-

    structural approaches to erosion control such as construction setback

    lines are not specifically authorized by the Act.

         To the extent that zoning concepts can be applied to the control of

    beach erosion. counties and municipalities have the authority via zoning

    regulations to exercise controls.13 The General Assembly had delegated

    broad zoning powers to local qovernments.14 and it is clear that techni-

    aues such as setback lines can be adopted by local zoning authorities.

    In addition. any zoning reauirement which applies to "critical areas"

    under the South Carolina Coastal Management Act is subject to incorpora-

    tion into the Coastal Council's management plan.15  In effect. a local

                   �                                                        ~~~~~~~~~~~~~~~~~~~~91

             zoning regulation affecting property subject to beach erosion, if consis-

    I       ~~tent with state policy, can become part of the state coastal management

            plan and be enforced by the Coastal Council.

                  in summary, there is adequate power to regulate beach erosion con-

    3 ~~trol methods, structural or non-structural. While primary responsibility

            for the problem has been assumed by the General Assembly, it has not

    3       ~~acted to the fullest extent of its authority.  Non-structural solutions

            have not as yet been addressed by the Legislature and, consequently,

            the Coastal Council has no authority to proceed in this area.

      3               ~~~~~Problems Associated with the Control of Beach Erosion

            Non-Structural Solutions and the Taking Issue

     I           ~~~As discussed above, the South Carolina General Assembly has authoriz-

    3 ~~ed setback lines as a land use control device which may be employed by

             local zoning authorities. The constitutionality of legislation autho-

    5 ~~rizing setback lines has been established since the United States Supreme

             Court upheld use of the technique in Goreib v. Fox.16 The general validity

    I ~~of setback lines rests on several factors. First, a setback line, since

    3       ~~it prohibits use of only a portion of the property, has minimal impact

             and allows beneficial use of the remainder of the land. Secondly, re-

    3       ~~strictions on the owner's use of his land are generally considered to

            be balanced by benefits such as uniformity of appearance and assurances

    I       ~~of space for light, air, and recreation.  Finally, considered on a com-

    3 ~~munity-wide basis, setback restrictions are considered as contributing

             to the public good by furthering health, safety, and welfare. These

    3 ~~same considerations have resulted in the upholding of the constitutiona-

             lity of the setback concept in South Carolina.17

     I           ~~~Setback lines are currently used in several coastal states as a

                    5                                                           ~~~~~~~~~~~~~~~~~~~~~92

    I        ~~method for restricting construction in areas with critical beach erosion

    I        ~~problems.18  The constitutionality of setback lines specifically for
              preventing erosion damage has been upheld in Spiegle v. Borough of

    S        ~~Beach Haven.19  The New Jersey Supreme Court there upheld a local ordi-
              nance which established setback lines for oceanfront property subject to

    I        ~~severe storm damage.  The court concluded that in light of the poss-4bk1

    3        ~~property losses setback restrictions could prevent, their benefit to

              the public outweighed any decrease in the plaintiff's property values.

    5        ~~Significantly, the court stated that even though the effect of the set-

              back ordinance might be to prohibit all construction on a particular

    I        ~~piece of property, that alone was not sufficient to support a claim of

    3        ~~unconstitutional taking.  The owner, to sustain such a claim, must also

              show that no beneficial use could be made of the property as a result of

    5        ~~the setback line.  Construction of a building likely to be damanged or

             destroyed by future erosion was not viewed by the court as a use bring-

    I        ~~ing real economic benefit to the landowner.  In a companion case where

    3        ~~the landowner was able to demonstrate that a-proposed building would be

             economically feasible and able to withstand storm forces, application of

    3        ~~the setback line to prevent construction of the building was held to be

             a taking.'

     I            ~~~The Spiegle decision is of course significant for its upholding of

    g        ~~the constitutionality of setback restrictions for the purpose of protec-

             tion against property loss from beach erosion. Because of the general

    3        ~~use of setback restrictions in the United States and in South Carolina,

             its application to oceanfront property here most likely would be viewed

    3        ~~favorably by the courts.  Less clear is whether South Carolina courts

             would uphold the validity of setback restricitions on facts as extreme

                   1                                                        ~~~~~~~~~~~~~~~~~~~~93

    I       ~~as the Spiegle decision -- this is, where the landowner's property is

    3 ~~not deep enough to allow any significant construction landward of the

            setback line. While there are South Carolina cases suggesting that a

            zoning scheme which depreciates property values is not a taking merely

            because of the decrease in value itself,20 there has generally been

    U       ~~another use which could be made of the land (for example, use as a

    3 ~~residence but not as a business).

                 While setback lines appear to be a viable approach to prevention

    5 ~~of property damage from erosion oceanfront property,21 there likely

            will be individ~ual cases where courts will find application of the

    U ~~restriction unconstitutional. Such a case may occur where the restric-

    3 ~~tion totally precludes construction on the property or so significantly

            reduces the owner's options (building a small house where larger homes

    5 ~~would be allowed on adjacent property) that he is placed at a significant

            disadvantage relative to adjoining property owners.

    I       ~~Engineering Solutions

    3       ~~Liability for Damages Caused by Engineering Approaches

                 It is of course possible that construction of an erosion control

    3 ~~structure at one point on a beach will result in damage to another pro-

            perty owner, perhaps by increasing erosion rates at the adjacent site.

    3       ~~If these circumstances arise as a result of a structure approved by the

    �       ~~Coastal Council, the question becomes one of whether the state may be

            liable for approving a structure whose propensity for causing damage

    3       ~~should have been foreseen.  A corollary issue is whether the landowner

            having the structure built could be liable.

     I           ~~~Controlling the first issue is the existence of the sovereign im-

                    1                                                          ~~~~~~~~~~~~~~~~~~~~94

    I       ~~munity doctrine in South Carolina.2  The state and its agencies cannot

    5       ~~be sued unless permitted by statute or unless state action results in a

            taking of property without just compensation. On the question of authori-

    3       ~~zation of suit against the state, the South Carolina Coastal Management

            Act of 1977 is silent; however, Coastal Council regulations specifically

            state that "in no way shall the State be liable for any damage as a result
    5       ~~of the erection of permitted works.1123  While administrative interpretations

            are not binding on the courts they are persuasive, and in light of the

    3       ~~absence of a specific statutory waiver of immnunity in the Coastal Management

            Act itself, there is little likelihood that damage suits would be permitted

            against the state as a result of Coastal Council action.
     3           ~~~State liability for damages caused by permitted erosion control struc-

            tures, if it exists, must then be based on the taking of property.24 While

    3       ~~direct confiscation by the state of privately held land to control erosion

            would clearly support a taking claim, situations not involving a direct

    I       ~~physical invasion, but which do cause damage, are more troublesome.  The

    3 ~~law is relatively clear that such non-trespassory invasions can be takings,

            prime examples being government owned airports whose externalities so in-ter-

    3 ~~fere with the use and enjoyment of surrounding land that property values

            are diminished. 25 Construction of an erosion control structure which phy-

    I ~~sically interferes with adjacent property by increasing erosion rates

    3 ~~arguably is an analogous situation if the structure is state owned and on

            state land. No cases appear to exist directly on this point and the issue

    I       ~~is unresolved. 26

                 Liability of private property owners is somewhat clearer. In general,

    I       ~~ordinary priciples of tort law apply to the design, construction, and effect

                    1                                                         ~~~~~~~~~~~~~~~~~~~~~95

    3      ~~of erosion control structures.  Assuming the elements of the case can be

           established, an owner or contractor could be liable in negligence or nui-

    U      ~~sance if the structure damages adjacent property.  Specifically, if damage

    *      ~~should have been foreseen in light of available information then a private

           action could succeed. Difficulties seem to lie more with proof than with

    3      ~~the theory of liability itself.  Sand transport processes are complex and

           affected by so many factors that it might be difficult to Es5tablish that

    I      ~~erosion or other damage is the result of an erosion control structure and

           not due to some other combination of factors. Assuming adequate proof, how-

           ever, improper design, construction, or location of an erosion control

    *      ~structure which causes damage could subject either the property owner or

           builder to liability.

     3         ~~~Ownership of Accreted Land

                Assuming that erosion control structures are successful, there may be

    I ~incidences of beach accretion significant enough to raise the question of

    3     ~ownership of the newly formed beach.  This problem may be of special signi-

           ficance if the accreted land becomes deep enough to permit new development.

    3     ~The South Carolina Coastal Management Act of 1977 specifically addresses

           this point. S.C. Code 48-39-120 provides that "no property . . . accreted

    I     ~as a result of natural forces or as a result of permitted structures shall

    3 ~exceed the original property line or boundary" and that accreted property

               t...shall remain the property of the state held in trust for the people

    3 ~of the state." The statute also prohibits development of accreted property

               1...beyond the mean high water mark as it existed at the time the ocean-

    I ~front property was initially developed."

      3         ~~~The provision clearly seems designed to prevent development of any kind

                   5                                                          ~~~~~~~~~~~~~~~~~~~~96

    5      ~~on accreted land and does so by attempting to vest title to the land in the

           state and by directing the Coastal Council to permit no development. Seve-

    I ~~ral justifications for this position can be raised. Public access to

    3 ~~beaches is -protected under this approach. It also insures a structure-free

            zone in areas where the beach is shifting, thus minimizing the possibility

    3 ~~of property damage if the newly accreted land is subsequently eroded.

                There exists judicial authority for this position. California courts

    I ~~have viewed accreted land as part of the tidelands trust with title to

            accreted land vested in the state.27 Because accreted land is part of the

           public trust, it can only be alienated for uses consistent with trust pur-

    3 ~~poses.28 California's position is justified primarily on the importance

            to the state in retaining control over trust property. Allowing private

    I ~~control over trust land could deprive the state or its subdivisions of the

            power to regulate coastal development, especially in harbors and recrea-

            tional areas. Finally, beach access could be significantly affected if

    3acc acreted  land falls into private ownership.  The California approach, dis-

            tinguishes between accretion due to natural or artificial means.29 Land

    5      ~~accreted as a result of man-made structures such as groins or jettys is

            considered to be trust property belonging to the state while naturally

            accreted land is the property of the littoral owner. Little justification

    3      ~~is given for this distinction.  Perhaps it is based on the idea  that all

            oceanfront property owners are entitled to an equal opportunity to have lit-

    3 ~~toral current sand deposited on their land, and any artificial interference

            with the sand transport mechanism deprives the owner of his right to the sand.

    U ~~Whatever the justification, the effect of the distinction is to vest title

    3 ~~to artificially accreted land in the state.

                    1                                                       ~~~~~~~~~~~~~~~~~~~~97

     U         ~~~Generally, courts have not accepted the approach taken by Califor-

           nia or by the Coastal Management Act. Most jurisdictions which have

           considered the matter have held that accreted land is the property of the

    3      ~upland owner.30  They reason that, since the oceanfront property owner

           must bear the loss if land is eroded away, fairness dictates that he

    U      ~receive the benefit if additional land accretes.  Further, a significant

    3      ~~component of the value of Ilittoral property is direct and immediate ac-

           cess to the ocean. Denying the oceanfront landholder title to accreted

    3      ~land could significantly affect the value of his property.  Finally, some

           courts assert that economic efficiency is promoted by vesting title to

    3      ~~accreted land in the littoral owner because it will encourage productive

    g      ~~use.

                The South Carolina Supreme Court has dealt directly with the issue

    3      ~~of accretion only infrequently,31 and no case has interpreted the accretion

           provisions of the Coastal Management Act. However, existing decisions

    U      ~~seem to conform to the generally held position that accreted land belongs to

           the littoral landowner and not to the state.   In Epps v. Freeman-32 the

           Court indicated that, at least with regard to natural accretion, such land

    3      ~~would belong to the landowner and not the state.  This ruling suggests that

           the South Carolina Supreme Court's position on title to accreted land may

    5      ~~differ from the position taken in the Coastal Management Act.  Given the

           potential importance of the issue, litigation is likely and there is at

            least some likelihood that the accretion provision could be held unconstitu-
    3      ~~tional on the ownership issue.

                            Implementation of Erosion Control Policy

    3      ~~Non-Structural Solutions.

                 Coastal Council adoption of erosion controls based on land use philoso-

                    �                                                        ~~~~~~~~~~~~~~~~~~~~~98

           phy, such as setback restrictions, has not been authorized by the General

           Assembly. In order for the Council to take such action, the Coastal

    U      ~~Management Act of 1977 would have to be amended to give the Coastal Council

    5 ~~needed authority. As an alternative, especially if the need for unifor-

           mity is not important, local zoning authorities seem to have the power to

           adopt setback restrictions or other land use controls which could limit

           development on the oceanfront.33 Such regulations, once approved by the

    *      ~~Council, would then be enforceable as Coastal Council regulations under

    5 ~~the Coastal Management Act. This approach could work reasonably well in

           areas of localized critical beach erosion assuming, of course, that the

    3 ~~local zoning authority will enact the necessary controls. In conclusion,

           either a uniform approach with regulations promulgated by the Coastal

    I ~~Council or a county-by-county approach could successfully address the pro-

    3 ~~blem with a minimum of legal difficulties.

           Engineering Solutions

     *          ~~~Legal problems associated with implementing engineering solutions to

           the problem of beach erosion appear to be minimal. The Coastal Council has

    I      ~~adequate permitting authority over erosion control structures on state lands

           and waters and general control over any structure in "critical areas" in

           the coastal zone. The Coastal Management Act appears broad enough to regu-

    5 ~~late whatever engineering solutions that might be proposed and legal problems

           associated with Council regulatory activities do not appear significant.

    *      ~~The major problem to be anticipated seems to be over the question of title

    3 ~~to accreted land. This problem probably will not affect Council authority

           since, regardless of ownership of accreted land, the Coastal Council retains

    *      ~~regulatory power over structures on the land.

                Problems with implementing engineering solutions may lie more in terms

                    1                                                          ~~~~~~~~~~~~~~~~~~~~~99

    3       ~~of financing than with anything else.  Major projects too expensive to

    *       ~~be financed by individual landowners will have to rely for funding on

            either federal or state money34 or on a local financing arrangement such

    3       ~~as a County tax or special assessment district.

                  Prior to the adoption of Article 8, section 7 of the South Carolina

    I ~~Constitution which vested broad powers of government in the individual

             counties, the General Assembly created a special erosion district for

             Pawley's Island and a public service district for Fripp Island, which

    3       ~~also could deal with erosion problems.  These districts had authority

             to issue bonds to pay for erosion control activities35 and the bonds

    *       ~~were to be retired by taxes on property owners within the district.

            After the adoption of that article, counties now have the power to pro-

            vide public services and to provide for their financing. The statute

    3       ~~authorizing counties to provide for and finance public services, while

            not specifically mentioning erosion protection, is so broad that such

    3       ~~an activity almost certainly is within the power of the county to under-

             take. As long as the cost of the improvement falls on those who receive

             it and not on residents of the county, assessments could be made on less
    3       ~~than a county wide basis.36  There appears to be no significant problem,

             then, should coastal counties decide to es~tablish erosion control dis-

    5       ~~tricts and tax the residents of the districts to pay for improvements.

             Determining who benefits for the purpose of inclusion within the district

    I       ~~will of course have to be established in some reasonable fashion.  Assum-

    3 ~~ing that can be accomplished, counties under existing law can finance

             erosion control projects.

                    5                                                           ~~~~~~~~~~~~~~~~~~~~100

                                             FOOTNOTES

             1.   United States Constitution, Article 1 � 8.

    1        ~~2.   Excluded from this discussion is legislation dealing only with

     3            ~~~federal cost sharing of erosion control projects.  Numerous

                  statutes establish cost sharing and cost analysis procedures

     3            ~~~for the Office of Management and Budget, the Water Resources Council

                  and the Army Corps of Engineers. In essence, the federal share

     I            ~~~of beach restoration projects is as follows:  50% on publicly

     3            ~~~owned shores, 50% on privately owned shores with public access,

                  and 70% on shores which can meet criteria for public shore parks.

     3            ~~~In addition, federal flood control legislation authorizes up to

                  70% federal funding for hurricane protection and beach erosion

     U            ~~~projects.  For, additional information, see Digest of Water Resources

     5            ~~~Policies, Department of the Army, EP 116S-2-1 (1975).

             3.   33 U.S. C. A. � 401 et sq

    3        ~~4.   33 U.S.C.A. �� 1251-378.

             5.   16 U.S.C.A. �� 1451-64

    *        ~~6.   Not only do the coastal states have policy making and regulatory

                  authority over private activites which affect the coastal zone,

                  but the Federal Coastal Zone Management Act requires that federal

     *            ~~~agencies conduct activities in a manner "lto the maximum extent

                  practicable, consistent with approved state management programs."

     *            ~~~Applicants for federal license or permits must obtain state

                  certification that the activity requested is consistent with the

                   state coastal zone management plan. The effect of the consistency
     3            ~~~provision of the federal state is to allow states significant control

                  over federal activities within the coastal zone.

                                                                    101

    7.  See State v. Yelsen Land Co., 265 S.C. 78, 216 S.E.2d 876 (1976);

        State v. Hardee, 259 S.C. 535, 193 S.E.2d 497, Cape Romtain Land &

        Improvement Co. v. Georgia-Carolina Canning Co., 148 S.C. 428,

        146 S.E.2d 434 (1928).

    8.  S.C. Code Ann. 48-39-20 (1979 Supp.)

    9. Id. � 120(A).

    10. Id. � 120(B).

    11.  Id. � 120(C).

    12. Id. � 130.

    13.  The Coastal Management Act deals exclusively with the permitting of

         structures and alterations of "critical areas" in the coastal

         zone.  The Legislature did not make any general grant of regulatory

        power to the Coastal Council aside from the power to require permits

         for certain activities in the coastal zone. For a comprehensive

         discussion of the Act, see Note, The South Carolina Coastal

         Zone Management Act of 1977, 29 S.C.L. Rev. 666 (1978).

    14.  See, e.g. S.C. Code Ann. 4-27-10, authorizing counties to establish

         zoning plans, and S.C. Code 5-23-10, vesting the same powers in

         municipal corporations.

    15.  S.C. Code Ann. 48-39-100(B) (1979 Supp.).

    16. 274 U.S. 603 (1927). See also City of Miami v. Romer, 58 So. 2d

         849 (Fla., 1952).

    17.  Dunbar v. City of Spartanburg, 266 S.C. 113, 221 S.E.2d 848 (1976).

         See also, S.C. Code Ann. 5-23-10 which authorizes municipal

         corporations to establish regulations on the percentages of lots

        which may be occupied.

                                                                    102

    18.  Florida and New Jersey probably have the most comprehensive

         regulations utilizing this approach.

    19.  46 N.J. 479, 218 A.2d 129 (1966), cert. denied, 385 U.S. 831

         (1966); 116 N.J. super 148, 281 A.2d 377 (App. Div. 1971).

    20. Talbot v. Myrtle Beach Board of Adjustment, 222 S.C. 165, 72

         S.E. 66 (1952).

    21   There are other possible approaches.  For example, open space

        preservation regulations which require developers to set aside

         a certain portion of land for public use are an accepted

         land use control device. They are, however, generally more

         susceptible to constitutional attack than setback lines, because

         they require the entire tract to remain undeveloped which limits

        most economical use.

    22. See Morris v. South Carolina Highway Dept., 264 S.C. 369, 215 S.E.2d

         430 (1975); Graham v. Charleston County School Board, 262 S.E.2d

         314, 204 S.E.2d 384 (1974).

    23. South Carolina Coastal Council Regulation R 30-4(F).

    24.  Under generally accepted principles of law, a "taking" can occur

        when a substantial reduction in the value of the affected property

        occurs.  The South Carolina Supreme Court has interpreted Art. 1,

         � 13 of the South Carolina Constitution, the provision which requires

        just compensation for a "taking", to mean that "taking" and "damaging"

         are synonymous.  See Spradley v. South Carolina State Highway Dept.,

         256 S.C. 431, 182 S.E.2d 735 (1971).

    25.  For South Carolina cases establishing this principle, see Kline v.

         City of Columbia, 249 S.C. 532, 155 S.E.2d 597 (1967); Owens v.

        South Carolina State Highway Dept., 239 S.C. 44, 121 S.E.2d

         240 (1961).

    26.  The argument was raised in Carpenter v. City of Santa Monica, 63

        Cal, App. 2d 772, 147 P.2d 964 (1944). There a city-owned break-

        water caused erosion to the beach.  Plaintiff argued that the city

        was responsible for causing the erosion and should be liable in

         damages or under a taking theory.  The claim was mooted because

         the court held that the plaintiff did not in fact have title to

         the land lost.

    27.  City of Los Angeles v. Anderson, 206 Cal. 662 275 P. 789 (1929).

    28. Marks v. Whitney, 6 Cal. 3d 251, 491 P.2d 374, 98 Cal. Rptr.

         790 (1971).

    29.  For a discussion of the difficulties in distinguishing natural

         versus artificial accretion, see Carpenter v. City of Santa

         Monica, 63 Cal. App. 2d 272, 147 P.2d 964 (1964).

    30. A leading case is Michaelson v. Silver Beach Improvement Association,

         342 Mass. 251, 173 N.E.2d 273 (1961).

    31.  The most recent decision is Epps v. Freeman, 261 S.C. 375, 200

         S.E.2d 235 (1973). See also Town of Port Royal v. Charleston,

         136 S.C. 525, 134 S.E. 497 (1926); Spigener v. Coomer, 8 Rich.

         301, 64 Am. Dec. 755 (1855).

    32.  261 S.C. 375, 200 S.E.2d 235 (1973).

    33.  See discussion accompanying note 14.  Beaufort County has already

         adopted such an ordinance.

    34.  See note 2 for a short treatment of funding for beach erosion

         projects.

    35.  See S.C. Statutes at Large 994 and 1042 (1962).

    36.  S.C. Code Ann. 4-9-30.

                                          CHAPTER VII

           I                              ~~~~~~~~~CASE STUDIES

                   To consider the appropriateness of alternate erosion control

    3        ~~strategies along the South Carolina coast, case studies are presented

              for the following locations:

          I                          ~~~~~~~~Hunting Island,
                                    *Hilton Head,
                                    *Pawleys Island, and
          I                         * ~~~~~~~Myrtle Beach.

              The four sites differ in both physical characteristics and development

    I        ~~patterns.  As such, they offer a good cross section from which to

              evaluate erosion control projects. The following section outlines the

              methodology employed; it is hoped that the suggested methodology

    3        ~~will provide a basis for evaluating future projects.

    I        ~~Methodology

     3            ~~~~Each of the analyses begins with a consideration of beach morphology

              at the site in question. Long-term and short-term beach profiles are

    3        ~~examined to determine the relative stability and erosional-depositional

              trend at specific locations along each of the sites. In addition,

    I        ~~significant influences affecting the beach's dynamics are considered.

     3            ~~~~Based upon these observations, alternative solutions deemed to be

              most appropriate for the site are suggested. The construction costs for

    3        ~~each of the alternatives are made.  In some cases, high and low cost

              estimates are made pending on site study. To the extent possible, the

                                                                             105

    1        ~~relative effectiveness of the proposed solutions is projected.

                  The benefit derived from erosion abatement is collectively equal

             to the potential prevention of property and recreational loss, Potential

    I        ~~loss is estimated by projecting past erosion trends along sections of

    3        ~~the beachfront.  It is well understood that shifts in any of the sig-

             nificant variables affecting beach formation may alter present erosional

    3        ~~trends;  nonetheless,  past trends serve as logical first approximation

             for projection. Current property values are estimated from county tax

    I        ~~assessments (and updated where appropriate.)  Lots in the affected

    *        ~~area are delineated to reflect depreciation during erosion.

                  Recreational benefits are estimated as the difference in visitation

             potential with and without the proposed projects. Visitation projections

             are made for each of the sites, while beach capacity is estimated by

    I        ~~calculating the area of dry sand beach (at MHW) and dividing by 100 square

    1        ~~feet, the necessary space for one visitor assuming a turnover rate of one.

             Visitation is valued at $2 per visitor day.

     3            ~~~Benefits and costs are projected in constant dollars, i.e.  without

             allowing for inflation. As such, an inflation-free discount rate is

    I        ~~applied to estimate present values of both costs and benefits.  By

    3        ~~comparing these figures, the benefit-cost ratios are estimated for each

             of the proposed projects based upon the available data and the assumptions

    *        ~~being made.

             Limitations of the Analysis

     I            ~~~The evaluations are intended to serve as a point of departure in

             evaluating the proposed projects. They are based upon interpretation

                                                                      106

    U         ~~of the best available data sources.  As noted previously, the accurate pro-

              jection of erosion rates requires both an interpretation of past trends as

              well as an understanding of the dynamics affecting beach formation currently

              and over the projection period. Without accurate information on wave climate,

    3         ~~~tidal influence, and onshore and offshore formations, it is difficult to pro-

              ject with confidence beach width and location. Particularly when estimating

    I         ~~~carrying capacity for recreational use, such imput is obviously important.

     3             ~~~~The alternatives considered at the sites are engineering solutions.

              Their feasibility is considered relative to the "no action" alternative

    5         ~~which assumes that erosional trends continue unabated and that present lind

              uses are representative. Redevelopment to higher uses and new development

    I         ~~~are not considered which may understate the potential benefit of the solutions

              considered. On the other hand, the incorporation of management solutions may

               lessen the need for engineering approaches by positioning new development at

    3         ~~~safe distances from the oceanfront.  Perhaps more importantly, given the

              rapid depreciation schedules used in most resort communities, and as a result,

    I         ~~~the frequent redevelopment of sites, the location of replacement structures

    3         ~~~away from the eroding shoreline may limit potential property loss and reduce

              the need for engineering alternatives as a long-run solution. Under such an

    3         ~~option, the 50-year planning horizon employed below may be longer than approp-

              riate. Formal incorportion of depreciation schedules and management solutions

    I         ~~~applied to replacement is not considered; yet, it is speculated that the

    3         ~~~benefits of such an approach from a long-run perspective could be most Sig-

               nificant and bear closer attention to complement the alternatives considered below.

     3             ~~~~No attempt is made to factor out state and local shares of benefits and

               costs. As such, the relative distribution of project costs and of recreational

    3         ~~~benefits must be disaggregated by state and local policy-makers in evaluat-

               ing returns on project expenditures.

                             CASE A: HUNTING ISLAND

                                Beach Morphology

         Hunting Island is bordered by Fripp Inlet at the south and St.

    Helena Sound to the north.  The island is presently eroding at a rate

    of about 300,000 yd3 /yr.  (230,,-00:m3/yr).

         The data base documenting depositional-erosional trends on Hunting

    Island is more extensive than for other areas in South Carolina because

    of interest generated by repeated nourishment projects. Available data

    sources span different time scales (Table A-i). Information provided

    by each source, therefore, has particular limitations and advantages

    and must be treated accordingly.

    Long-Term Shoreline Changes

         The trend of long-term shoreline changes of Hunting Island has been

    strongly erosional with the highest rate of erosion near the entrance of

    Johnson Creek (Fig. A-i).  Low water positions compiled from nautical

    charts (1857-1979) show that the greatest sediment loss took place at

    the north and south ends (Fig. A-i). Continuous erosion between 1857

    and 1979 resulted in shoreline retreat of 300 to 750n along the northern

    half of Hunting Island. The southern half has also suffered significant

    erosion historically, but portions of this section have reversed to

    short-term accretional trends. In part, long-term changes in the

    position of the beach are related to sediment budgets around the shoals

    associated with Fripp Inlet at the south end and St. Helena Sound and

    Johnson Creek to the north. The correlation between morphologic changes

    in the Fripp Inlet system with shoreline changes on Hunting Island clearly

                                                                      108

    Table A-1 DATA BASE: Hunting Island Shoreline Changes

    Nautical Charts (National Ocean Survey)

    Chart 154  1857  1:80,000

    Chart 154  1920  1:80,000

    Chart 793  1937  1:40,000

    Chart 793  1961  1:40,000

    Chart 793  1972  1:40,000

    Chart 11517  1979  1:40,000

    Aerial Photo Sets

    1939

    1951

    1955

    1959

    1968

    1972

    Beach Profiles

    1974-76 Survey

      Station HIO1, HI02 (7-8-74 to 8-17-76; sixteen surveys).

      Station HI03  (9-20-75 to 8-17-76; six surveys).

    1979-80 Survey

      Stations HI-l, HI-3, HI-5, HI-6, HI-7 (11-18-79 to 7-23-80; at

      approximately monthly intervals).

                                                           109

                                           I  .  HARBOR
                                           ' ISLAND -

                                          coos m   lA'    #    4CA/z! o

          1857  SHORELINE
           1937 SHORELINE                      0

    I1~~~~~~~~1s FRIPP INLET

                               FRIPP ISLANDm

           Figure .k_1 Long-term changes on Hunting Island compiled
             fromnautical charts between 1857 and 1979.

                                                                    Ito

     indicates the interrelation between inlet and shoreline dynamics. There

     has been an apparent net exchange of sediment between Hunting Island

     and Fripp Island. Net accretion at the northeast point of Fripp Island

     amounted to approximately 500 m from 1857 to 1979. Correspondingly,

     the southwest point of Hunting Island was cut back by 400 m in the same

     period. An inverse relationship exists between accretional and erosional

     trends on the sections of Hunting Island and Fripp Island near the inlet.

          The effects of bathymetric changes in St. Helena Sound on Hunting

     Island are apparent from computerized wave refraction analysis using the

     1857 and 1978 bathymetry of St. Helena Sound.  A wave refraction diagram

    of a 4-second wave from the east superimposed on the bathymetry of

     the 1857 nautical chart shows a convergence of wave orthogonals on the

    northeastern end of Hunting Island (Fig. A-2. The historical changes

     already documented indicate heavy erosion along this section.  A wave

     refraction diagram based on the 1937 nautical charts still shows con-

    vergence of wave energy near the northeast end of Hunting Island (Fig.

     A-3).  Much of the wave energy concentration was due to the presence of

     the ebb-tidal delta developing at the mouth of Johnson Creek that drained

     eastward since erosion of the north section of Hunting Island.  Between

     1937 and 1978, erosional rates slowed at the northeast tip of the island,

     although shoreline retreat continued. Changes in shoal configuration

    and shifts in channel position in St. Helena Sound also affect the long-

    term erosional trend of Hunting Island. In the period between 1857 and

     1978, significant changes took place in the tidal channel system of

    St. Helena Sound.  By 1978, much of the energy of eastward approaching

    waves was dissipated over the shoaling areas where deeper tidal channels

                  I~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~D III

    ~~~~~Figr A. erciono -eod ae rmte atoe h
    ~~~~~~15bahmtyin h iiiyo utn sadadS.Hln
    I~~~~~~Sud

                      I                                     ~~~~~~~~~~~~~~~~~~~~112

     I~~~~WR
                    I~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~o EEAMW  4 ERMNS3

    ~~~~ig ueA3-ercino -edwvsfo h atoe h
    I~~~13 ahmty

                    5                                                          ~~~~~~~~~~~~~~~~~~~~~113

              formerly existed in St. Helena Sound (Fig. A-4). In addition to the

    3        ~~effect of changes in St. Helena Sound bathywpetry on wave refraction

              patterns, the Fripp Inlet ebb-tidal delta is also a zone of concentrated

    I        ~~wave energy (Fig. A-4).  This indicates the importance of waves in the

              by-passing process exchanging sediment between Hunting and Fripp Islands.

              Shoreline Changes from Aerial-Photographs

     f            ~~~~Sequential vertical aerial photography of the Hunting Island Beach

              taken at four to twelve year intervals between 1951 and 1972 was used

    I        ~~to determine shoreline position by Hubbard et al.  (1977).  This survey

    1         ~~shows net changes over shorter intervals than published nautical charts

              and indicates more recent depositional-erosional trends.

     3            ~~~~Data from six photo reference points between the years 1951 and

              1972 are summarized in Table A-2. Also included with these data are

    I        ~~shoreline changes measured from nautical charts between 1859 and 1933.

              Deposition-erosion graphs for several of the photo control points

              summarize trends of shoreline change along Hunting island (Fig. A-S).

    3        ~~Superimposed low water shorelines from the 1951, 1959 and 1972 aerial

              photo mosaics of Hunting Island indicate more recent and shorter-term

    5        ~~shoreline changes (Fig. A-6).

                   From the tabulated and graphical data, it is clear that a 5000 m

              section of Hunting Island beyond the direct influence of Fripp Inlet and
    5        ~~Johnson Creek has been eroding continuously over time.       Because the

              data acquisition techniques provide net shoreline changes over variable

    5        ~~time intervals, calculated average yearly rates of shoreline change

              depend on the time interval selected. Table A-3 lists yearly rates of

                                                                                                                           114

    ~~~~~~UIsY
                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~STpee'  RIEit                     IRK O   He

    ~~~Fig ueA4Rfato f4scn  ae  rmteeatoe h
     I~~~~98 ahmty

                                           4km

    �I /E

    1
                                                * H-4

                                             .200

                                             .1000'ia
                                              a"0   1W3  5160
                                              .000
                                             0200~ 11-

                                             d00
                                              -200
                                             1..ooy

                                             0000     331 311072 l~

    II

                I~~~~~

                 Figure A-S Depositional-erosional trends along Hunting Island
                   compiled from vertical aerial photographs and nautical charts.

                                                                      116

                                              HARBOR ISLAND

         I~~~~~~~~~~ILN

                                                    1972

                                             .99-------
                                   : ......
                             HUNTI NG ISLAND

    ~~~~~igr A6Sprmoelwwatrsoeisfom15,99an
                 1972 aer.-i-       a p       se
                                                                KM
       3~~~~~~~~( <,                        LOW WATER LINE
                                  / Ad        ~~~~1972
                            /   FR-*          1959?^----; _

                          / FRIPP ISLAND    X*199
                                   --- .'iK

         I~~~
            1~~~~~~~~~~~~17
                                     A-,~~~199...........

    5        ~~~Figure Al-6 Superimposed low water shorelines from 1951., 1959 and
                 1972 aerial photo sets.
      I~~
       ~~~~~~~~~~~~~~~FIPiS A D, .

                                                                                 117

          Table A-2 Hunting Island shoreline changes in meters (1859-1972)

          Reference  Change        Change    Change    Change    Change    Change    Change
            point    1859-1914   1914-20   1920-33   1933-51   1951-55   1955-60   1960-72
            H 1       -1478          36        -73        -46       -27        -89        544
            H 2         -491       -41        -106       -188       -17          0        -39
            H 3         -154          0        -37        -51       -52        -55        -32
            H 4               85               -65       -124       -36        -26        -24
            H 5              -102             -101       -177       -14        -25         77
            H 6              -337              -22       -284        22          0        197

            Table A-3 Average yearly shoreline change in meters, based on 25, 50 and
                       100 year trends on Hunting Island.

                    Station             25 Years            50 Years           100 Years
                      H 1                +20.3              +5.9                -10.0
                      H 2                 -2.7              -6.7                 -7.8
                      H 3                 -6.6              -4.4                 -3.4
                      H 4                 -4.1              -5.3                 -1.7
                     -  H 4               +1.8              -4.6                 -3.0
                      H 6                +10.4              -1.7                 -3.8

    I

    I

    I

                    3                                                          ~~~~~~~~~~~~~~~~~~~~118

              change for the six Hunting Island reference stations based on 25, 50

    3        ~~and 100 year intervals.  Rates of shoreline change are similar in

              magnitude for all three intervals, but, in the shorter term, erosional

    I        ~~trends at the north and south ends of Hunting Island reversed.

                   At present, shoreline changes along the extremities of Hunting

              Island are controlled by sediment budgets and sand by-passing at

    3        ~~Fripp Inlet and Johnson Creek.  Shoals associated with the ebb-tidal

              deltas of the inlets adjacent to Hunting Island have been built up

    I        ~~recently and provide some protection from wave attack.  A portion of

              the sand for these shoals may be derived from erosion of the central

              portion of Hunting Island. Inlet tidal channels and inlet shoal

    I        ~~systems are dynamic and continually evolving, however, and local sed-

              iment budgets can be altered drastically in short periods of time. For

    5        ~~this reason, effect of inlet changes must be included in any considera-

              tion of beach erosion management options for Hunting Island.

              Short-Term Changes

     3            ~~~~Beach profile surveys have been conducted over periods of 6months

              to two years at one month or two month intervals (Hayes, Moslow and

    5        ~~Hubbard, 1977).  The beach profiling technique described by Emery (1961)

              can be used to measure elevation changes at an accuracy of + I cm. The

    I        ~~detail of each profile depends on the discretion of field personnel.

    j        ~~Enough detail is included to record the morphology of the primary dunes,

              incipient dunes, any berm development and slope of the foreshore to the

    5        ~~~low water line..

                   I Hunting Island beach~profiles: 1974-1976. - A beach profile

    I        ~~survey conducted at one to two month intervals between July, 1974 and

                                                                  119

    August, 1976 was designed to monitor three locations of the Hunting Island

    beach undergoing rapid change.  Station HI01 was located at the south of

    the island within 500 meters of Fripp Inlet (Fig. A-7). Station HI02,

    located near the lighthouse  and Station H103, located 500 meters from

    Johnson Creek, were within the limits of the 1975 nourishment project.

         The beach at Station HIO1 was typified by a relatively flat profile

    during the study period except for occasional low-amplitude ridge and

    runnel topography (Fig. A-8). The dunes near this location are 2 to 3

    meters high.  The seaward face of the dune at HI0M was cut back by

    approximately 10 over the study period (Fig. A-8).  Much of the dune

    erosion may have occurred during a storm between the July and August,

    1975 surveys.  The beach at this profile underwent net accretion, but

    was subject to an unusually large volumetric change (Fig. A-9). The

    mechanism of these changes was not observed  but may have been due to the

    influence of the nearby Fripp Inlet tidal delta.  Here, large volumes

    of sand are transported by waves and tidal currents as the configuration

    of the shoal complex continually evolves.  The sharp decrease in sed-

    iment volume at profile H102 between the June and August surveys of 1975

    approximately correlates with dredging in the borrow area on the Fripp

    Inlet delta (Fig. A-9.).  Dredging operations apparently interfered with

    the normal sediment budget during this time. After dredging was completed,

    sediment volume at this profile quickly rebounded (Fig. A-9J.

         Profile HI02 is characteristic of the erosional trend of Hunting

    Island.  Prior to the beach nourishment project, H102 was generally flat

    and featureless without any measurable berm development. The beach was

                                                          120

                           BEACH PROFILES HUNTING ISLAND

                    HARBOR ISLAND

                          :I    g~~HI-!

                   o "/

                  I   7           - HI-3

                                HI-5

                                          0   .5   1         2

           HS~         Hi-7          t.=  PROFILES 1974 - 1976
                       HI--1         He-I PROFILES 1979- 1980

             i  FRIPP INLET                 +

    FRIPP ISLAND

        Figure A-.7 Location of Hunting Island beach profile
          stations.

                                                                                      121

                                                            1IOl    t  7.,

                                      tf

                                                        IDII1D*EL ~ ~ a  Ici

                                                            Is 7

                                   I  'I
                                      II                       lii   ic  I   75

                                       as
            ~~~~ I

                                      II

                                                            cHan istS a lr p

    I
                                                            !I11  *ic 2 1 75

                   Figur      e  A-8 Compar lson o� beach proi iles �rom selected dares
                      between August, 1974 and August, 1976 at station HIt:1.  Net
                               tchange is shown in lower plot. G    7

      350 -

    I  300 -
    ca'                                                            l  \t   H  02

     0  250 -                          0
    LU

       15o

        1975 00
    I)I

    C   50-
    u

               1974     1975                       1                  1976

      .100
      .100  '  m  '   I  I  I  I  '  I     I  I I  *  *  I  I           I *   !  I t  !
            A S 0 N D J  M A   J  J S O N  DJ F M A M   J  A SO

      Figure A-9 Volumetric change in cubic meters per meter of beach
        between survey dates at Hunting Island profile stations HI01,
        HI02, and HI03.

                                                                  123

    backed by a steep dune scarp that underwent episodic retreat (Fig. A-10).

    The net gain of sand at profile HI02 over the study period is the result

    of the beach nourishment project in 1975. Seasonal trends are masked

    in part by the artificial fill at profile H102, but significant de-

    creases in sediment volume during the winter months of 1975 and 1976

    may be natural seasonal trends (Fig. A-9).

         After completion of the beach nourishment at this profile, a dis-

    tinct berm developed. A moderately-erosional trend continued until the

    end of the study period as the berm crest migrated approximately 45

    meters landward.

         Profile H103, surveyed only after completion of the nourishment

    project, maintained a more consistent ridge and runnel topography compared

    with the other two profiles (Fig. A-11). This profile tended to be ac-

    cretional during the post-nourishment period; whereas HI01 and H102

    underwent net erosion during this time (Fig. A-9). Because of the

    proximity of this profile to Johnson Creek, deposition-erosional trends

    and beach morphology are, in part, controlled by sediment transport

    and morphologic changes around the associated ebb-tidal delta.

         II  Hunting Island beach profiles:  1979-1980.  -  Five new pro-

    file stations were established in November, 1979 as part of a year-long

    study of recent beach erosion problems on Hunting Island (Fig. A-7).

    Cumulative volumetric changes between November, 1979 and July, 1980 at

    each profile location are shown in Figure A-1.2. Similar to the 1974-76 set

    of profiles, part of the natural depositional-erosional trends are masked

    by a beach nourishment project completed between January and April, 1980.

                                                                                        124

          ~I ~~~                                       H la2 i*H 2M e  7

                                             ~~~S                .5O~~~~~'S$ a       7S

    r~~~~~~~~~~~~~~~~~~~~~~~I

                                           II~~~~~~~~~P8 I'i          '

                                    9 I

                                           I;r~~~~~~~~HO  1315 7. : 7?

                                    S
                                   !,

                                   I

                                   =!          NET CHANGE

                  Figure A-1OComparison of beach profiles fromi selected dates
                    at station HI02.
    I~~~~~~~~~~~~~~~~~gw1'Z^7

                                                                                                                     125

                                           zii
                                                    J~~~~~~~~~HO i~i
                                                                              5103 3  S     II 75

                                                                  CISGCE
                                                                              M103  moo 2 ~la VS

    I~~                                                                      ~~~~~~~~~~~~~~~ 14DO leo I I JS
                                           Zs

                                           a

                                                                              M1Z03 " i  a~ is
                                           H.L

    ~~I
                                                                  UISIAM

                                           1  SI

                                           'a
             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Iq    t I                                    I

                  Figur           e  A-11    Comparison of beach profiles from selected  dates
                      at station H103.
                                           jta
                                                                               H1U3  l~bs I? $ 7&

                                            CI                NET CHANGE?

                                            G.el    Hvue   evu  ,   eemlM lb .I -,M  C th ve  *,ek MM ~ 1MM    f
                                                                  0l*)i4#�t ICI

                                    at~~~~~~~~~~~~~~~~~~110 statio  H103.

     I~~~~~~~~~~~~~~~~~~~~~I

                                                                Hlt- I    t421 2  5 ec  126

                                         m'
    I

                                          S

                                         .,

                                                                  �HF-i    'Ir5 I .   'I1
                                         � $

    I =

                                         S

                                            tweenNovemer, 979 ad JulO190 si  e
                                               isshown~in     l-l  I1oS I1 ,t  4
                                         s.

                                          i

                                                                    &.0l  &�  bO

                       Figure A-12 Comparison of beach profiles from selected dates be-
                         tween November, 1979 and July, 1980 at station HI-1. Net change
                         1is shown in lower plot.
             I~ ~ ~ ~                                          121

                                                                   127

         Profile station HI-l, at the north end of Hunting Island, con-

    sistently showed ridge and runnel topography through the study period.

    Similar to station HI03, the morphology of this profile is strongly

    influenced by the morphology of the Johnson Creek ebb-tidal delta.

    At low water, this profile station may be up to 200 meters wide (Fig.

    A-1), but during some tidal cycles, large runnels do not completely

    drain isolating an outer sand ridge from the beach.  The primary dunes

    at this profile are low and do not exceed 2 meters in relief. A dis-

    tinct berm is usually present, dividing the beach into a flat backshore

    and an upper foreshore dipping seaward at a slope of 1.5 to 2 degrees.

    This section of beach, although subject to frequent morphologic changes,

    remained relatively stable with respect to volumetric changes (Fig.

    A-133. A net volumetric loss occurred between November and July. Most

    of the loss took place during January and February, possibly a sea-

    sonal change.

         Profile station HI-3 is at the north limit of the most recent

    beach nourishment project (Fig. A13).  Here, a 2 meter high scarp has

    been cut into the primary dunes. No permanent berm is developed, and

    ridge and runnel topography is low in relief or absent during surveys

    prior to beach nourishment (Fig. A-14). The nourishment project added

    approximately 100 cubic meters of sediment per meter of beach (Fig.

    A-14). Morphology of the post-nourishment beach included a berm crest

    and a foreshore zone dipping at 1.5 to 2 degrees (Fig. A41). Ridge and

    runnel topography was persistent on the post-nourishment beach.  The

    July, 1980 profile at station HI-3 is comparable in morphology to the

                                                                                                          i 3 128

                                                                                                            m 51*

                     0

                     LU
                                                                                                            �HI S   a
                     U-   150

                                O~~~~~~~~1980
                     u9.
                     Is
                     LU

        1~~~z0

    I          =

         t~~~O.0

                                                                                  w:-3   :n_:  .

                                                  '-i  '=_'                     _
                                                                  3~~ I~~~r* ~~~~~129

                                                  I
                                                  '1

                                                   2J

                                                    1u  iii                               -s'  :s111 2 !
                                                   *)    h .0,6    1   4K::)                           r:

                                                              2(   t -~~~~~~~~~~~~~~~2

                                                   -!
                                                    ?
                                                    K.

                                                         _ j 4~~~~~~~~~
                                                   3'1
                                                            'j~ ~ ~ ~ ~ ~~~~. -                .?fl

                                                    *1r  r;.r  r-.r  IrHt �r.:  ::::;..:;-3   i:r : * m

                                                     I
                                                   --1

                     5                                            :  4-~~~~~~~ ~ ~6  .           . .        S .4    0.:~~~~~It*XC .R

                                                            g]~ ~ ~ ~ ~~~~"_ Mt-3                a :1 'a   '
                                                                                         5001 20 I D

                                                    2.
                                                    :2
                                                     I

    I                                                         a

                                                     ,5  .    . :  -    .;.  .  , . -   .:  -  _    L._   . -
                                                                        DIII�TMCC1

                       I   ~~~~~~~~~~~~~~~~0.~~~~1- SISS ;3I at

    I.�

                                                         I           ~~NET CHANGE

                           Figure A-14 Comparison of beach profiles from selected dates at
                              station HI-3.

                                                                   130

    July profile at HI-1.  Net accretion at HI-3 between November and July

    is due largely to the nourishment project, masking any seasonal trends.

         The beach profile at station HI-5, November through January,

    consisted of a gently-sloping foreshore and low relief ridge and runnel

    topography (Fig. A-1S). Dunes are low along this section of Hunting

    Island not exceeding 1 meter in relief.  A low artificial dune was

    created at 111I-5 during Februlary, 1980 when the nourishment project

    began. Similar to profile HI-3, beach morphology elements at HI-5,

    after the nourishment project, included a flat backshore area separated

    from the foreshore by a berm. In the post-project period, ridge and

    runnel topography has more relief, and the overall morphology of the

    beach changed considerably as the berm crest retreated landward

    (Fig. A-15). Net gain of sediment volume at this profile is the result

    of beach nourishment (Fig. A-13). A significant loss of the artificial

    fill took place during a two-month long erosional trend lasting from

    February to April, 1980. This loss may have been a seasonal effect andwas

    matched, in part, by erosion at profiles 1HI-6 and HI-7.

         Profile HI-6 is at the south limit of the 1980 beach nourishment

    project (Fig. A-7). The most outstanding feature at this location is

    a 3 meter high dune scarp below which the pre-nourishment beach sloped

    seaward at a low angle (Fig. A-16).  Relief features on the beach in-

    cluded low-amplitude ridge and runnel topography and no berm or back-

    shore and foreshore zones that underwent little change through the last

    survey in July.  An erosional episode between late January and mid-March

    may have been a seasonal trend but was interrupted by artificial filling

                                              3]                                   .'-5    '; .                                131

                                             ii
                                             :1                            -.-.  -.                  )

                                              'I

         3                                          0.00~~~~~~~~~~~~~~i1  ii.:   ,L c:  s00 Wotdoa.  pcc    lt~    ~lorn    c000  u0 Li  L~  ic
                                             rl
                                             I

                                              2
                                   Figure~~~~~~~~~~~~- A-5Cmariso of bahpoils  frmslceddtsa
                                              station Hl-5        .

                                              1.01rU lo~t COi   L00  10000 Io 107011o0 00l?  iCo 0  t o il, I000

         I~~~~~~~~~~~I
                                             :5

                                              *0L  11.00  4000  iOU   0e  10000pPf~lO 00 1000  0.0 ele   IeO Iboo

                                                                              NI-S    11io II   S c

         3~i                                                            -.113 S    S

                                                                 NET CHANGE

    3                 ~~Figure A-45 Comparison of beach profiles from selected dates at
                       station 111-5.

                                                 3  .....                     ,    . ,            132

                                                                         3n-B  III: 15 2   80
                                                   �f~~~~~~~~~~~r~ ,;, , 2 ,

                                        1                              353 73 3

                                        r!

    *~~~~~~

                                         s
    *~~~~~~~~~~~~~~~~~~~~~~                                      ItI  J%
                                                     I~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~1
                                                                         Hi-6  1025  3 15 62
                                        ,.t
                                                  Dl,~~~~~~~~~~n ii0s

                                        ?
                                         !                              3129 M 22  a  S

                                         5 I

                                        i
                                        3a

                                         000M   0340   .00    00 00  0 0 303   .3100PI~*~)O   5030 i* .4503  03300
                                         J                              I 10 1 .   .

                                        - V

                                        '                             -
                                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~'~

     I~~~~~~~~~~~

     I~~~~~~~~~~~

                                                                             "u-  205  II  II8  72~
               3                    1                              l~~~~~~~~~~~~~~~~~~~~~ll~~~~I2   23  7   80

                                         t

                                                          NET CHANGE
                                         P''   "Di "p 'ir "0: F'-isi 'etE ^ kX 2- aUI "I �@ :  @v�

                    Figure A-16 Comparison of beach profiles from selected dates
                        at station HI-6.
     I~~~~~~~~<

     I ~ ~ �st

                                                                    133

    in late March (Fig. A-13).

          Station HI-7 is well south of the nourishment project and, as at

    station HI-i, reflects more natural depositional-erosional trends.

    At low water in this location, one or more ridge and runnel sets may be

    exposed (Fig. A-17). These formations are associated with tidal deposits

    around Fripp Inlet.  Flood oriented bedforms superimposed on sand ridges

    at the base of HI-7 indicate that this areas is adjacent to a flood-

    dominated marginal tidal channel.  The beach is somewhat protected from

    wave attack by the shoals around Fripp Inlet and, at the present time,

    has an adequate sand supply through exchange with tidal-delta deposits.

    Profile HI-7 fluctuated between erosion and deposition over the eight

    month study (Fig. A-13). The net result was a small volumetric gain by

    the end of the study.  Profile HI-7 compares with profile HI-1 at the

    north end of Hunting Island in that both are influenced by the morphotogy

    and sediment budget of an adjacent tidal inlet.

                               Engineering Solutions

          In past years, the response to Hunting Island's erosion problem

    (Shoreline retreat of about (28 ft per year) 8.Sm per year has been large

    scale beach nourishment. In simple terms, beach nourishment replaces e-

    roaded sand with material borrowed from a nearby source.  Ideally, the

    source should be the deposition zone of the erosion process, but, alter-

    native sources can be used if the material is similar to the native beach

    sand.  Four nourishment projects have been completed at Hunting Island to

    date, (Table A-4).

         In addition to the beach fill, a terminal groin was built in 1969

    ($179,000) to assist in fill retention.  The following assesments of

                                                                                                                                            134

          I~~~~~~~~~~~~~~~~~~~~~~~~~

                                                               !                           t*   V

                                                                  ~,~~~~~~~~~~-  -        tt    - 41Cte

                                                                       NE C H A N G E 0

                                            Figure A.-,1.7  Comparison  o~~~~~~~flbahpoilsfosecteddts        a

    a                                                                 $17   usttion HI-7

                                                                             135

      TABLE A-4

      Historic Project Costs for Beach Nourishment at Hunting Island.

                                           TABLE A-4

             Date           Cubic Meters*   Limits of          Unit Cost**       Total***
         Accomplished        Placed (yd )    Placement         $1m3 ($/yd3)   Project Cost

      2/27/68 - 12/5/68        573,416        50 + OON to          N/A           $435,178
                              (750,000)      50 + OOS

      5/6/71 - 12/18/71        582,074        50 + OON to          N/A           $534,000
                              (761,324)      50 + OON

      4/5/75 - 6/5/75          468,652        60 + OON to          2.45          $971,540
                              (612,974)      30 + OOS             (1.88)

      1/16/80 - 5/1/80      1,080,080         24 + 60N to          3.21        $2,267,201
                           (1,412,692)       97 + OOS             (2.45)

     * Includes overfill

     ** Unit cost to payline

    *** Cost data based upon project specifications, not the actual volume of sand
        placed.

                                                                   136

    future projects was prepared by the Corps in 1977.

              "The initial work was completed in the fiscal year ending
         30 June 1969.  Federal participation was supposed to end 10
         years thereafter--June 1979. The actual language in the auth-
         orizing document (House Document 323, 88th Congress, 2nd
         Session) was to the effect that local interests would be re-
         quired to: contribute 30 percent of the first cost of the
         project construction, a sum currently estimated at $136,000,
         and agree that during the 10-year period following initial
         construction they also will contribute to the periodic nou-
         rishment work 30 percent of the costs thereof, a sum
         estimated at $29,500 annually."

              This 10-year limitation on Federal participation was
         extended to 15 years by Section 156 of the Water Resource De-
         velopment Act of 1976.  This 15-year limit would expire 30
         June 1984 in the case of Hunting Island. In addition to the
         nourishment in FY 1977, there could be nourishments in FY 1980
         and FY 1983.  These changes could increase the project costs
         (Federal and non-Federal) by about $3,420,200, which, if
         added to recent 10-year (PB-3) cost estimates of $3,830,000,
         would make a total present estimated 15-year cost of $7,250,200.??

         The 1977 fill was delayed until January - May of 1980 at a cost of

    $2,267,201.  This recent fill was considerably larger than the previous

    projects, probably due in part to the delay from its scheduled 1977

    completion. (Figure A-18).

         The recent beach nourishment project is typical of possible future

    plans for Hunting Island. With the possible inclusion of a groin field,

    there will be a comparable renourishment every three years.  It is the

    intent of the present PRT research project to determine if this nourish-

    ment could be made more effective and if additional structure should

    be considered.  In addition, PRT is interested in the probable con-

    sequence of no future beach fill, that is, a do nothing alternative.

        The past fill projects offer the best guidelines to future costs

    at Hunting Island. The volumes and frequency of fill appear to be

        _t  , ~,__85'
    L 10 -

            M.L.W.                     EXISTING
    w
    -J

        0      50     100     150    200      250    300    350    400    450         500

                                           DISTANCE  (Ft.)--

                  Fig. A-18. Hunting Island Nourishment Profile

                    1                                                         ~~~~~~~~~~~~~~~~~~~~138

    I       ~~reasonable, and have a favorable benefit cost ratio according to the

    3 ~~Corps analysis. There is no reason to believe that this solution

             could not be continued indifinitely from an engineering perspective.

          3                            ~~~~~~~~~Benefit-Cost Analyses

                  The principle benefits accruing from erosion control measures taken

    I ~~at Hunting Island stem from: 1) the prevention of property loss and

    3 ~~2) the prevention of recreational loss. The following section estimates

             values for these potential benefits and compares them with the estimated

    3        ~~costs of further beach nourishment at Hunting Island.

             Property Loss

     U           ~~~The potential loss to be prevented is a function of the rate of

    3        ~~erosion anticipated over the planning horizon.  As Hunting Island has

             been highly erosional over recent history, two scenarios were projected

    3        ~~using alternate erosion rates.  Annual erosion rates observed over the

             past 25 years and the past 100 years were projected forward over a 50 year

    I        ~~planning interval.  Although conditions affecting shoreline formation over

             the recent past may not exist in the projection period, the estimates

             assume that long-term erosional trends are captured and that these trends

    *        ~~will continue.

                  Because Hunting Island is a state park left predominantly in a natural

    I        ~~state, the value of its structures is considerably less than at the other

             three sites considered. The location of the existing structures is shown

             in Figure A-19. Based upon erosional/accretional trends observed over

    3        ~~the past 25 and 100 year periods, potential property loss and expected

             lifetime of the structure are calculated for both public and private fa-

    3        ~~cilities on the island.  The present value of the property loss is then

                                                                      139

                           *i~e        HA rRBOR
                                        1SAAND

                                                       TERMINNL GEOIN

                                                       I

          U  -         N.~f~Lijqhtho                       o~.1

             3~~                                     9
                                      -J

        a                                -%    A1~~~~~~SZ
                                  Co               *

    3     A~~43

                      Fil~~~~PP   I ~~~Figure A-19

                                                         SCALE ?N FEET

                    3                                                         ~~~~~~~~~~~~~~~~~~~~140

    N        ~~computed using constant dollars for property value and a 4 percent dis-

    3        ~~count rate (for reasons discussed previously p. 105).  The estimated

              property loss accruing under each of the erosion scenarios is presented

    3        ~~in Table A-S.

                   It should be noted that neither of the above scenarios result in

    I        ~~loss to the historic lighthouse or surrounding buildings which represent

    3        ~~the most important development on the island.  Neither of the scenarios

              considers the relocation of strucutes which has been employed in the

    3        ~~past to reduce damages on Hunting Island.  Theis overstatement of damages

              appears less important when considered relative to the substantial recre-

    I        ~~ational benefits that accrue at Hunting Island.

    3        ~~Recreational Benefits

                   The recreational benefits accruing from erosion control reflect the

    1        ~~value of visitor occasions saved as a result of the project.  In 1980, vi-

              sitation at Hunting Island was estimated to be 1,102,696. Projections for

    I        ~~the remainder of the 50 year planning period are based upon an earlier

    3        ~~study of recreation in South Carolina by Hartzog, bader, and Richards

              (1974). Visitation projections are based on population projections as

    3        ~~well as proximity and accessibility to each of the state beaches.  Table

              A- 6 lists average annual visitation for each the 5 decades during the

    I        ~~planning period.  Listed below is the distribution of visitor demand

    5        ~~according to day of the week for the 86 day summer season.

                   With periodic beach nourishment it is estimated that an average of

    3        ~~195 feet of dry sand can be maintained along the 10,000 feet feeder beach.

              Based upon a required area of 100 square feet per person, the estimated

    I        ~~capacity of the replenished beach is 191,500 users/day.  At present, only

                                                                            141

    TABLE  A-5

    Value of Property Loss on Hunting Island
     Under Alternate Erosion Scenarios

    Scenario I        25 Year Erosion Rate

                           Value             Lifetime         Present Value at 4% Discount
    Public Property

       Concession         $ 20,000             25 years                  $ 7,500
       Cabins:  #2          37,500             35 years                    9,487
                #3         37,500             35 years                    9,487
                #14        45,000             40 years                    9,360
                #15        45,000             40 years                    9,360

    Private Property

       10 Cabins at         13,240 each  2 @ 25 years                      9,930
                                          3 @ 30 years                   12,231
                                          4 @ 35 years                   13,396
                                          1 0 40 years                    2,753

    TOTAL                 $315,240                                        83,504

    Scenario II       100 Year Erosion Rate

                           Value            Lifetime          Present Value at 4% Discount

    Public Property

       Recreation
        Building          $ 50,000            25 years                   $18,750
       Cabins:  #10         37,500            25 years                    14,062
                 #11        37,500            25 years                    14,062

    Private Property
      7 Cabins
      at                    13,240            25 years                     4,965
                                       2 @   30 years                     8,154
                                       2 @   40 years                     5,506
                                       2 @   45 years                     4,528

    TOTAL                 $217,680                                       $70,027

                                                                     142

    TABLE A-6

    Projected Visitation and Recreational Value Accruing for Periodic Beach
    Nourishment at Hunting Island.

                               1980-90      1990-2000    2000-10    2010-20    2020-30

    1.  Visitation              1,168,857    1,309,120    1,466,214  1,642,159  1,839,219

    2.  Weekdays (60)              11,239        12,588        14,098      15,790     17,685
         Sats (12)                 16,859        18,882        21,147     23,685      26,527
         Suns (12)                 19,668        22,028        24,672     27,632      30,948
         Peak (2)                  28,098        31,469        35,246     39,475      44,212

    3. Annual Visitation
         with project           1,149,648    1,254,864    1,352,880  1,454,400  1,568,100

    4. Annual Visitation
         without project          994,074       838,500       838,500    838,500    838,500

    5.  Differential              115,574       416,364       514,380    615,900    729,600

    6. Erosion Control
         Benefit for 10 Year
         Period                 2,311,480    8,327,280   10,287,600 12,318,000 14,592,000

    7.  Present Value           1,900,037    4,621,640    3,857,850  3,116,454  2,495,232

    8.  Sum of Present Values                                                    $15,991,213

                                                                               14 3

              peak day activity exceeds capacity, but over the planning period, it is

    I         ~~estimated that weekend activity will become constrained even with the

              project and that weekday activity will approach capacity. Assuming a

              daily constraint of 19,500 visitors, therefore, annual visitation with

    3         ~~the project is listed as item 3 in Table A-6.

                   Without the project, it is estimated that the beach will signifi-

    I         ~~cantly-deteriorate after the first 5 years of the recently completed

              nourishment project. After that time, the beach and dune system will

              migrate, in some cases, with the high water mark meeting or exceeding the

    3         ~~tree line.  As a result, the available dry beach area will be reduced

              significantly during the adjustment process. Eventually, when temporary

    3         ~~stability is achieved, the beach width will again broaden allowing

              greater recreational capacity. It is important to note, however, that

              the island will continue to have recreational potential during such a

    3         ~~~transition al period as erosion rates will vary along the breadth of

              the beach area. For purposes of the present study, it is estimated that

    3         ~~beyond the first 5 years of the planning period, beach capacity without

              renourishment will average 50 percent of capacity with periodic nourish-

              ment. Item 4 in the table lists the projected annual visitation without

    3         ~~~the project.

                   The recreational benefit is found then as the differential between

    3         ~~values accruing with and without the project.  Item 5 in the table repre-

              sents differential usage for each of the ensuing decades. The

    1         ~~differential is-small in the first time period as the recently completed

    3         ~~nourishment project continues to produce benefit.  As erosion occurs with-

              out renourishment and weekday capacity is approached with the project,

    3         ~~~the difference widens.

                    I                                                          ~~~~~~~~~~~~~~~~~~~~144

     U            ~~~Corresponding erosion control benefits in current dollars are given

             in Item 6. User occasions are accessed a value of $2 per day (as previ-

             ously noted). The dollar value of benefits for the ten year period is

             found then by multiplying the average differential by $2 by 10 years. The

             present value of recreational benefits is derived by discounting the en-

    H        ~~suing stream of benefits at a 4 percent discount 'rate.  As benefit streams

             are estimated in current dollars, it is appropriate to use an inflation

              free discount rate, i.e., the market rate of interest with price expecta-

             tions deducted. This concept has been discussed previously by Hanke

              (1975) and Stepp, et al., (1975).

    U        ~~Project Costs

                  According to estimates by the Corps of Engineers, the cost of the 1980

             nourishment project at Hunting Island amounted to $2,267,201. Because of

              the delay between nourishment projects, a larger than normal amount of fill

             was required. Therefore, tow cost scenarios are estimated. The high-cost

    I        ~~scenario assumes that renourishment costs occuring every 3 years will

              continue at the 1980 level. The low-cost scenario assumes that renourish-

             ment costs will amount to 60 percent of the initial cost if maintained

             every 3 years. The project costs over a 50 year planning horizon are given

              in Table A-7 under both of these assumptions. Present values based upon

    I        ~~the 4 percent discount rate are also given.  It is estimated that the

    *        ~~present value of future expenditures may vary between $8.4 and $14 million.

              It is recommended that the high-cost scenario be used for present planning

             purposes given past cost overruns.

             Benefit-Cost Summary

     U            ~~~~Table A-8 presents a summary of benefits and costs of periodic re-

                                                                     145

    TABLE A-7

    Costs of Beach Nourishment at Hunting Island

    A.  Low-Cost Scenario

    Year                          Cost                      Present Value
     3                         $ 1,360,321                  $ 1,209,325
     6 1,360,321                                              1,074,653

    48                                                           12,152

    TOTAL                       21,686,270                    8,267,666

    B. High-Cost Scenario

    Year                          Cost                      Present Value

     3                        $  2,267,201                  $ 2,015,542
    6                           2,267,201                     1,791,088

    48                           1,533,333                       20,253

    TOTAL                       36,143,783                   13,779,443

                                                                      146

    TABLE A-8

    Summary of Costs and Benefits of Beach Nourishment at Hunting Island
    in Present Dollar Values.

    Item                          Benefit                      Cost

    Property Loss                 $    83,504
    (Table VI - 6)

    Recreational                   15,991,213
     Value
    (Table VI - 7)

    Beach Nourish-
    ment                                                      $13,779,4432

    TOTALS                          16,074,716                  13,779,443

    Benefit/Cost
     Ratio                               1.167

    'Based on 100 year erosion rates.

    2Based on high-cost renourishment scenario.

                                                                              147

    3         ~~nourishment at Hunting Island.  The only option considered is periodic

              renourishment of the beach under the high-cost scenario. As previous

    I         ~~nourishment projects have influenced recent erosion rates, only the 100

              year rate is applied to property loss. Under the assumptions that have

              been made, the benefit-cost ratio for a continuation of the project

    3         ~~~is estimated to be 1.167.

                   From the state perspective, the federal/state distribution of costs

    3         ~~~for future nourishment cycles will be an important determining factor.

              In addition, closer examination of shoreline retreat and carrying capa-

              city of the island without the project should be given as the major
    3         ~~justification for the project rests with the recreational value of the

              island to beach users.

          I                            ~~~~~~~~~CASE B:  HILTON4 HEAD

           I                               ~~~~~~~~~~Beach Morphology

                   Hilton Head Island is the largest beach ridge-type barrier on the

              South Carolina coast, originally formed by a series of prograding beach

    3        ~~ridges.  On the present-day island, this complex development pattern is

              indicated by beach-ridge sets that trend in several directions. Most

    3        ~~recent sets of beach ridges are parallel to the present shoreline along

              the southern half of Hilton Head. Along the northern section of the is-

              land, beach ridges are truncated and oblique to the shoreline, indicating

    3        ~~a zone of erosion.

                   In addition to larger dimensions, Hilton Head also differs from most

    I        ~~other beach-ridge barriers in that it is bordered by large estuary systems

              rather than a tidal river - salt marsh system connected with the ocean by

    I        ~~a relatively narrow tidal inlet.  The effects of tidal inlet - tidal delta

    3        ~~systems on the stability and sediment budget of adjacent barriers has been

              well studied (Fitzgerald et al., 1978; Hubbard et al., 1977; Nununedal and

    3        ~~Humphries, 1977).  Port Royal Sound to the north of Hilton Head and Cali-

              bogue Sound to the south have associated with them linear sand bodies and

    I        ~~shallow marginal channel systems that are continously shifting position.

    3 ~~Larger main tidal channels also exist, having evolved morphologically with

              time, although significant shift has not occurred. A study of the effects

    *        ~~of these changes on the littoral sand budget of adjacent sections of

             Hilton Head beach has not been conducted at this time.

     I            ~~~The data base that presently exists on trends of shoreline change

    3        ~~along Hilton Head consists of the five sets of aerial photographs at five

             to seven year intervals between 1951 and 1972, six editions of nautical

                                                                            149

            charts published between 1898 and 1978 and a two-year beach profile

    I       ~~study at four locations on Hilton Head conducted from 1974 to 1975.

            Changes in Shoreline Position 1898 - 1979

     3           ~~~Long-term changes in shoreline position along Hilton Head Beach

            alternate between zones of accretion and zones of erosion (Fig. B-i).

    I       ~~As suggested by truncated beach ridges, the section of shoreline between

    3       ~~Forest Beach and a point 7 km north of Folly Creek has undergone signi-

            ficant erosion between 1898 and the present (Fig. B-i). Net changes

    3       ~~north of Forest Beach were erosional from 1898 to 1979 ranging from 200

            to 500 m of shoreline retreat. Maximum shoreline retreat occurred along

    I       ~~an 8 km section of beach immediately south of Folly Creek.  Net migra-

            tion 1000 m to the south by the small tidal inlet associated with Folly

            Creek over the past 80 years indicates net sand transport southward at

    3       ~~least along this section of beach.

                 Depositional-erosional trends along the southern half of Hilton Head

    I        I~~sland have varied considerably in space and time (Fig. B-i).  The section

            of shoreline extending from the north end of Forest Beach to a point 9km

            to the south accreted seaward by up to 500 m from 1898 to 1922 (Fig. B-l).

    3       ~~Since 1972, however, the section of shoreline along Forest Beach has re-

             treated significantly. Maximum net erosion of approximately 200 m has

    I       ~~taken place near the center of the Forest Beach section between 1922 and

             the present.

                  The beach along the Sea Pines Plantation section of Hilton Head eroded

    3       ~~significantly between 1898 and 1922.  This zone has been more or less stable

             since 1922, however, undergoing either slight net erosion or slight net ac-

    3 ~~cretion. The southwest end of Hilton Head has developed by build-up and

                     ~~~~~~~~~~~~~~~~~~~~~ISO
                                                                            150

                Figure B. L

                    from nauticalchartsbetween1898and197.

                                  ~SEA P~ ~~~~ ~IESLTON HEADE ILAND
               I~~~~~~~~~~~~~~~~~~~~~~~~19 .....
               I~~~~~~~~~~~~~~~~~~~~~~~~92.....
               I~~~~~~~~~~~~~~~~~~~~~~~~~~~~17

    I        ~~~Figure B-i  Long-term changes on Hilton Head Island compiled
                    from nautical charts between 1898 and 1979.

    extension of a recurved spit. Morphology and depositional-erosional trends

    in this area are controlled by tidal circulation, sediment supply from

    shoals associated with the entrance of Calibogue Sound and sediment sup-

    ply from updrift, erosional areas of Hilton Head Beach.  Patterns of

    shoreline change along the recurved, distal end of Hilton Head were irre-

    gular between 1898 and 1922.  Zones of erosion alternated with zones of

    deposition and overall net changes were small.  Between 1922 and 1979,

    this area was strongly depositional (Fig. B-l) and extended 200 to 600 m

    toward the entrance of Calibogue Sound.  In contrast, the shoreline at

    the northeast end of Hilton Head on Port Royal Sound has been cut back

    extensively over the past 80 years.

         The overall trend of shoreline change on Hilton Head Island has been

    significant, with long-term net erosion along the northern half and a rela-

    tively stable to strong accretional trend along the southern half. Erosion

    along the southern portion of the island has been only local and of short-

    term duration.  This pattern lends support to the idea that beach erosion

    at the north end of Hilton Head is serving as a sand source for deposi-

    tional trends at the south end of the island. Direction and rates of

    longshore sediment transport on Hilton Head Island have not been well in-

    vestigated as yet, however. Related wave energy flux on the beach and

    shoreface of Hilton Head is also largely uninvestigated, but the effect

    of waves can be qualitatively seen in refraction diagrams of monochromatic

    waves over the present day bathymetry. Orthogonals of hypothetical waves

    approaching Hilton Head from the east, southeast and south tend to converge

    on the Forest Beach area and the northern half of the island (Fig. B-2 and

    B-3).  Convergence on Forest Beach seems to be, in part, a function of wave

                                                                        152

                                                           PCRT RATRL 5OUNC  SE 6-$se" ':,
                                     Clcr ~ ~ ~ ~ ~ ~ ~ R 'I S�ea :1*; I .'

    Figure B-2  Refraction of 6-second waves from the southeast over

       1979 bathymetry in the vicinity of Hilton Head Island.

                          over 1979 bathymetry1
    I                                                     .~����            ��;�           '1

                    1                                                          ~~~~~~~~~~~~~~~~~~~~154

            refraction over the offshore shoal known as Gaskin Bank.

    5       ~~Shoreline Changes 1951 to 1973:  Aerial Photographs

                 Intermediate-term trends of shoreline change have been documented

    U       ~~from five aerial photographic surveys of Hilton Head Island, completed

    3 ~~between 1951 and 1973. Changes. in shoreline position between each aerial

            survey date were measured at thirteen points spaced 1500 to 2000 m apart.

    3 ~~Analysis methods were similar to those described for the Hunting Island

            aerial survey, consisting of determining the high water line relative

             to fixed control points on scale corrected aerial photos.

     3           ~~~Results of the aerial photo analysis indicate trends similar to

             longer-term shoreline changes (Table B-1).  The most persistently ero-

    3        ~~sional sections of Hilton Head beach are along the northern half; whereas,

             the southern section has been stable to moderately accretional (Fig. B -4) .

    *       ~~The area of greatest erosion during the twenty-two year period of aerial

    3 ~~photo surveys was the section of shoreline enclosed by photo-control

             points J5, J6 and J7 (Table B-i Fig. B-4) north of Forest Beach. Only

    3        ~~one control point was established in the Forest Beach section of Hilton

             Head which has been retreating over the last sixty years. Intermediate-

    U        ~~term rates of erosion for this highly-developed area, therefore, are not

    3 ~~well known. South of Forest Beach, shoreline changes were either strongly

             accretional between photo survey dates or stable and no measurable change

    3 ~~recorded. The only exception to this trend was a significant loss of

             beach Along the recurved spit that underwent an episode of erosion be-

    I ~~tween 1951 and 1955 (Table B-2,.Fig-.S-4). Between 1955 and 1972, this

    3        ~~area resumed the long-term stable to accretional trend.

                                                                      2

                              HILTON HEAD ISLAND

     67
       5     4        3  KM
                                  T-1                                  0          4

           +200 T-2.                    +200rT-4                    +200-T-6
                            O/~~~ ,, ~~~~~1951
                 19511973                     119551973                 0      -1973
           -200                         -200 200                   -200
    +200 J-1                 +200-J-3                 +200                      +200-J-7
                                 ~951              1951 1973
          .19511973                     1973
    -200                     -200                     -200L                    -200

    Figure B-4 Depositional-erosional trends along Hunting Island compiled from vertical
      aerial photographs.

                                                                                        156

        TABLE B-1

    I North Hilton Head Island

    I   Reference              Change                Change               Change                Change
          Point                1951-55              1955-60              1960-66               1966-73

          J  1                    15                  -17                  30                    ND

          J  2                     0                  -16                   0                     1

    I    J  3                      0                  - 4                  -6                    36

          J  4                    31                    0                   0                     10

          J  5                    11                    0                 -23                   -15

          J  6                   -10                  -11                 -12                   -34

          J  7                    ND                  -36                   0                   - 9

    I

        TABLE B-2

        South Hilton Head Island

                                Change               Change                                    Change
                               1951-55              1955-66                                   1966-73

          T  X                   53                    0                                          0

    I   T 2                      62                    9                                          6

          T  3                   57                   27                                          0

    I     T  4                    0                   11                                          0

          T  5                  -66                    9                                         14

          T  6                  -66                   10                                          0

                                                                              157

    I        ~~Short-Term Changes:  Beach Profiles

     3            ~~~~Morphologic and volumetric beach changes along Hilton Head were

             recorded at four profile stations between September, 1974 and August,

    1        ~~1976.  The profile locations (Fig. B-4a) were not meant to be represen-

             tative of the entire island, but were systematically placed within zones

    I        ~~that have historically been both erosional and depositional.  Profiles

    3        ~~were surveyed a total of seventeen times over the two-year study period

             at intervals of one or two months.

     3            ~~~~Through the two-year study period, the beach at all four profile

              locations was subject to large volumetric changes (Fig. B-5) which corre-

    I        ~~late, to some degree, with morphologic changes from profile to profile.

    3        ~~Particularly well correlated were changes among profiles HH3, HH4 and

             HHS. An accretional period in August, 1975 (profile 3) and September,

    1        ~~1975 (profile 5) was followed by an erosional episode in October, 1975.

             A smaller, but still significant depositional-erosional period at these

    *        ~~profiles followed in December, 1975 - January, 1976.  Large positive

             changes in beach volume may correlate with the practice of beach scrap-

             ing. Overall, little net volumetric change took place at any of the

    3        ~~profile stations during the survey period.  No seasonal trends in mor-

             phology or volume changes were rated. Seasonal changes may have been

    I        ~~masked by the effects of beach scraping.

                  Profile station HH2 at the north end of Hilton Head (Fig. B-4aj is

             located in one of the more stable sections of the island (Fig. B-i). The

    3        ~~beach profile at this location was composed of a low well vegetated dune

             and a flat beach with superimposed ridge and runnel topography during

    3        ~~the time of the study (Fig. B-6).  The one or two ridge and runnel sys-

             tems that were nearly always present at this location were usually low

                                            157a

    ' .
            'SEP~HILTON         HEAD ISLAND

     Figure B-4a. Location of Hilton Head
       beach profile stations, 1974-76.

                 3                                                                ~~~~~~~~~~~~~~~~~~158

                          60-                                         HH2

                          40-
                                      I                        I
                          20-

                           0I

                         -20-                          .

    U                   ~~~~~~~~~~~~-40
                                      I                        I

                                      I                       I
                          60-         I                              OHH3

                          40-

                          20-

                      *  -20-

                       o  -40-

                       o  60-                                        X HH4
                       z

    I~~~~~~
                          40-

                          20
                       3
                       >
                          0

                         I  -                                 V

                         -40

                                    60                              9~~~~~~~~~~~~~~1 HHS

                          40-

                          20-

                          20-
                                1974             1975 1               1976

                             S  ND j F MAM JJASONO M            FMAM S 0   AS

                    Figure B-S  volumetric change in cubic meters per meter of
                       beach between survey dates at Hilton Head profile sta-
                       tions HH2, HH3, HH4 and HH5.

                                                                                                                         159

                                                                                     HH12         11OG  1o  ii
                                       g_                                                                     13qo  15  11  74

                                      3g

                                       '0.00    0.00   40b.00   6b.00      .0OO            Io0.00    2o0.00   10.00   6o0.00 IbO.OD  00.00
                                                                     DISTRNCE  111
                                                                                     HH]2         1540  13 2   75
                                       .                                                                      18001 30  3   75

                                     x

                                                                    OIS:RNCE IMi
                                                                                     HH12         1645  17  s   16

                                       Oa.D0    2b.co   *b.o    6b.00   eb. 00    I o.oo  0  .o0  gio0.00   I0.I00  180.00  2bo.00

                                                                                     HH12         ISY0   2       75

                                                                =;'
                                     orj

                                              r~~paH   12 IS45  17  5   75

                                     station H2. Net cnange is shown in lower plot.
    I~~~~~

    Ig

                    1                                                          ~~~~~~~~~~~~~~~~~~~~~160

    U        ~~relief features, but, during spring and summer months, sand ridges oc-

    5        ~~casionally attained amplitudes of 50 cm or more.

                   The beach at HH2 was relatively wide compared with beaches more cen-

    3        ~~trally located along Hilton Head.  Three large fluctuations in beach

              volume took place compared with the first survey of the study (Fig. B-5).

    U ~~These changes occurred during 1974 and 1975; whereas, changes during the

    3        ~~second half of the study were positive, but not large.  The abrupt, large

              fluctuation may be related to periodic beach scraping, but no records are

    3        ~~avaliable to support this conclusion.

                   Profile station HH3 is located approximately 4 km south of HH2 in a

    U        ~~zone that has historically undergone significant erosion (Fig. B-l).  The

    3        ~~beach at this station is the narrowest of the four profiles measured,

              averaging 110 m wide at low water. The dune ridge at this location is

    3        ~~approximately 2 m high and was artificially constructed from dredge mate-

              rial. This man-made dune was subject to frequent truncation by wave

    *        ~~attack over the study period and apparently has been repaired during beach

    3        ~~scraping exercises (Fig. B-7).

                   The most significant feature of the volume change plot (Fig. B-5)

    5        ~~based on beach profile data is a large positive change between the August

              23 and September 19, 1980 surveys. The sediment fill resulted in a flat

    I        ~~beach relative to the ridge and runnel system present during the previous

    5        ~~survey (Fig. B-7).  A large net loss of sediment was recorded at the next

              survey (November 2, 1975) followed by a partial rebound in beach volume

    3        ~~by November, 1975 (Fig. B-5).  Rather than a natural depositional-erosional

              episode, these abrupt changes seem to be related to the beach scraping

    I        ~~practice.  Such large, rapid changes and flat accretional beach profiles

                          U                                                                    ~~~~~~~~~~~~~~~~~~~~161

                                                                                          HH~ 1057 ?G 9 74

     I                       ~~~~~ ~~~~~~ ~~~~~~ ~~~~0.0Do  20.0   Do0.00  SO.0  Oa   aa  DoI b.00    1".00   t4o4.00  140000   460.00   200.00
                                                                                     H HI  153I00 23 6 /5
                                                                                               1 303  1 9  9    75

                                                     0. 00  2b.  O   4b.  Do  Sb   Do  8b. co   6   :"-Do  1 0, 0 iS   00   I   o00 02 200.00o

                                                                    DISTANCE NIM

                                                                                    H~i 3  i097 26  3   74
                   I                                                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~910 i39 875

                                                                    1113TQNCE  454

    I                    ~~~~~Figure B~7 Comparison of beach profiles from selected
                                      dates at station H1H3. Net change is shown in lower
                                      plot.

                                                                    162

     are not common under normal conditions. An alternate explanation might

     be the effects of a storm or storms or an unusual set of wave conditions.

     The correlation of abrupt depositional-erosional changes among the Hilton

     Head profiles during this part of the study could be explained by storm

     effects.  Similar to profile HH2, the beach at HH3 underwent a period of

    �slow net accretion over that latter part of the study, but, overall, the

    beach at profile HH3 showed nearly zero net change over a two-year period

     (Fig. B-5).

          The profile designated HH4 was positioned near Forest Beach, an area

     that has been moderately erosional since 1898 (Fig. B-l).  The beach here

     was backed by a low natural dune covered with sea oats (Uniola) at the

     time of the study.  Ridge and runnel topography was persistent through-

     out most of the two-year study (Fig. B-8). Periodically, a distinct

     spring tide berm developed 15 to 20 m seaward of the dunes, particularly

     associated with periods of ridge and runnel activity.  Trends of volume-

     tric change generally correlate with changes in profiles HH3 and HH5, but

     depositional-erosional patterns were not as large or as abrupt.  The

     large volumetric changes spanning August, September and October, 1975,at

    other profile stations were represented at profile HH4 by a moderate

     erosional period (Fig. B-5).

          A period of significant deposition between the beginning and end of

     November, 1975,followed by erosion during December was similar to changes

     at the other Hilton Head profiles during this time. The beach at HH4

     seemed relatively stable between January and August, 1976, but only four

     surveys were completed over this period, and large fluctuations may have

     been overlooked. At the end of the two-year study, a small net accretion

                          1                                                                      ~~~~~~~~~~~~~~~~~~~~163

                U                                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~HH14   9 3 1  1 tO 704
                                                        ____________________________________________  4~~~~~~2405   15    11   74

    U~~~~~~~~~~~~~~~'

    ~~~~~~~~~~~~~~I

                                       0.00  20. 00  40.00  60.00  oo. 00 .2 2640 10 00  1400a0 160 00    ~00.00    200.00

    I                       0~~~~~~~~~~~ ~~~~~~~ ~~0.00a  26 Do  ait.00  6000  00. 00  0o. 00    tho oo    ;Oa    O. OD.0  00.00    200. 00
                                                                       DISTANCE (Ml

                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~HHI    q 4023K7

                 I                                               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~HI-I!4 530 ~2 9 744
                                                                                                    i02?  1 9  8    76

    I                  ~~~~~~~~~~~~~~~Figure B-8. Comparison of beach profiles from selected
                                     dates at station HH4.  Net change is shown in
                                     lower plot.

                    I                                                          ~~~~~~~~~~~~~~~~~~~~164

    N        ~~of sand was recorded at HH4.  The beach was morphologically similar at

    *        ~~the time of the final survey compared with the initial survey.

                  Profile HH5 is near the southern end of Hilton Head just within the

             recurved spit section. Here, the beach is under the influence of the tide-

             dominated shoals marginal to Calibogue Sound. The beach is wide, avera-

    U        ~~ging 150 m from the dunes to the low water line and frequently has one or

             more high amplitude ridge and runnel systems moving across the beach

             (Fig. B-9). The 2 m high dune ridge at this location is artificial, well

    *        ~~vegetated and was not subject to erosion through the two-year study.

                  A low spring tide berm was frequently present at HH5 and usually as-

    I        ~~sociated with ridge and runnel activity.  Similar to profile HH3, the

             beach at HH5 was subject to large volumetric changes between August and

             September, 1975. The pattern here was nearly identical to station HH3

             except that the maximum volumetric peak occurred in August rather than

             September (Fig. B-5). Another volumetric peak was recorded in November

    I        ~~followed by significant erosion in December, 1975.  Again, it is not

    *        ~~certain whether these abrupt changes are related to beach scraping or

             storm effects. The general pattern at profile HH5 included large, pos-

             sibly man-made depositional-erosional cycles, but nearly zero net change

             through the two-year study.

           I                            ~~~~~~~~~Engineering Solutions

     I            ~~~As discussed in the preceding section, Hilton Head has a relatively

              stable shoreline. Some erosion is taking place; the trend being moderate

    *        ~~retreat along the northern half and accretion along the southern end.

              Most of this erosion appears to correlate with individual storm periods.

    I        ~~At the present, individual property owners are using a wide variety of

                                                                                                                      165

                                                                                 HHI5     954  i  1  74
                                                                                            1200 15 I 1 74

                                   I

    I~~~~~~~~~~
                                    'O.0   20.00  40 O        8b0O.00 be60.0 OD0.00 o 200,Go 0.0. co I. 0.00  200.Oa
                                                                 OISOSNCE IniI
                                                                                 HHI5      1720 15 7  75
                                    I                                                    14100 23 8  75

                                   A

                                   S

                                  WIa
                                   I

                                    0 00O  20.00  4000  sb.oo  8b.oo  the. 00  00.0  OD10.o  28 0.00    1h0. 00  200a.00a
                                                                 OISTANCE (Ml
                                                                                -H1HI5    830  25 6 9 74

                                                1~~~~~~~~~~~~~~~~~~~~~~~~~ 100 I2 I8 1275

                                   000    200   40.0    Do 6.  o    .3bo  oo  000   140.00.K   -     0.0  00.040  20-,'O 0.0 0

                                                                      0 1 3 f 14 N C     10 E8   8    7
    I~~~~~~~~~

                                                                013746CE IMl

                              Figure B-9, Comparison of beach profiles from selected
                                  dates at station HH5.  Net change is shown in lower
                                  plot.
               I~~~~~~~~~~~~~~~H5801 17

    I ~             ~"                                                                  oj2 27

                                                                              166

             erosion control techniques including beach scraping (from foreshore to

            backshore), beach nourishment, dune restoration, bulkheads (sandbags) and

    I ~~riprap. Many of these techniques have had unsatisfactory results.

                  Beach scraping has become a popular erosion control prodecure in

            South Carolina, particularly after severe storms. Although no documented

             evidence exists that it is a viable engineering plan, there is some data

            that suggest that the net effect of removing sand from the foreshore

    I       ~~accelerates erosion.  A comprehensive study of this practice should be

            made before it is adopted as an erosion control alternative.

                 The use of sanbags for bulkhead construction has met with only
    *       ~~limited success in areas exposed to direct attack by ocean storm waves.

             Individual property owners in the North Forest Beach area have used

    I       ~~sandbags, but they failed during Hurricane David.  Alternative materials

            for bulkhead construction and riprap has also been used, generally in a

            discontinuous, non-uniform manner, resulting in increased erosion due to
            the presence of a bulkhead on the adjacent shoreline. This problem

            underscores the need for comprehensive shoreline protection, as opposed to

    *       ~~fragmented solutions.

                 Beach nourishment has been used at North Forest Beach to control

            erosion and more recently at Palmetto Dunes. Sand was borrowed from a

            site on the marsh side of the island, an area where a marina is under

            construction. Nourishment provides both a recreational beach as well as

            a defense from storm waves and tides; thus, for this area, it seems to be

            the most reasonable erosion control alternative.

                                                                    167

    Beach Nourishment

         Two exemplary projects are considered to illustrate the feasibility

    of beach nourishment at Hilton Head.  The first alternative considers

    nourishment for 25,700 feet of feeder beach near Folly Inlet; while the

    second alternative considers nourishment for a 3,000 foot stretch at North

    Forest Beach.  Figure B-10 shows a typical cross-section for the Hilton

    Head shoreline in the North Forest Beach region. The fill design includes

    a 50 ft (15 m) berm at an elevation of 10 ft (3 m) above MLW. Because

    no data was available to evaluate potential borrow areas, a range of unit

    costs have been used to estimate total costs.  Based upon the fill profile,

    the volume requirements were estimated at 67 yd /ft (52 m 3/m).

    TABLE B-3

    Nourishment (3000 ft., 915 m)

    Sand/yd3                           Total

     $3                              $  603,000

      $4                                 804,000

      $5                               1,005,000

     $6                                1,206,000

                           Benefit-Cost Analysis

         Hilton Head Island has developed over the past two decades into one

    of the most exclusive beach resorts in the country. While most of the

    island is relatively stable and the individual plantations generally have

    followed sound building patterns, the location of expensive dwellings on

    or near the oceanfront poses a potential for property loss. Presently,

    severe erosional problems are being observed at the North Forest Beach

    section of the island.  To alleviate present and potential loss, beach

    nourishment has been considered as an alternative in the past (Corps of

           BERM

    io    -     1
                                           W  EXISTING FIL-                                 --FILL

                                  IJ  EXI STING F ILL

     0          50         l00         150        200         250        300          350        400

                                              DISTANCE         (Ft.)

                            Fig. B-10- Proposed Nourishment - Hilton Head

                    1                                                          ~~~~~~~~~~~~~~~~~~~~169

    3        ~~Engineers, 1974).  The Corps considered beach nourishment alone and in

             conjunction with structural solutions. Nourishment was considered for

    1        ~~10.4 and 6 mile sections with unjustifiable returns in both cases.  The

             following analysis will provide an update and reconsideration of the

             earlier study.

             Prevention of Property Loss

                  Property values at Hilton Head are based upon the 1978 tax assessment

    3        ~~for Beaufort County.  Current market values were estimated by calculating

             monthly appreciation on subsequent market sales and extra polating

             property values forward to July, 1980. It was found that properties

    I       ~~appreciated at a 28 percent annual rate between 1978 and 1980.  As the

             remaining oceanfront properties are developed and value due to scarcity
    3       ~~becomes still more significant, it can be assumed that properties at

             Hilton Head will appreciate at a faster rate than the real estate market

    I       ~~as a whole.  For this reason, property loss estimates at Hilton Head may

    5       ~~be slightly conservative when discounting future property values.

                  As incremental property loss is realized throughout the erosion process,

    I       ~~properties are divided into segments to reflect partial loss at designated

             tirae intervals. Figure B-11 depicts components contributing to property

    1'      ~loss, the concept being similar to a property loss model employed previously

    5       ~~in Michigan (Armstrong, et al., 1979).  Potential land loss can be disaggregated

             into amenity and risk components. The former component includes the

             public beach from which amenity value is derived; the latter component begins

             as private property is eroded and is assumed to be most significant in the

    I       ~~first two quadrants.  Table B-4 presents proportiate land values derived

    3 ~~for beachfront and second row lots. The difference between the two results

                                                                         170

    I       ~~as second row land does not include amenity value.  The percentages reflect

    U       ~~relative weights derived from a sample of property values for lots at

            Myrtle Beach in Case D.

     5           ~~~The distribution of building values in Item C of Table B-4 is based

             upon an observation of construction patterns on the island. No formal

    I       ~~sample was conducted as was done at Myrtle Beach, but in general, buildings

             at Hilton Head are setback from the beach and most often located in the

            third quarter of the lot.

                  Because recent erosion rates at Hilton Head are more reliable than

             longer-term estimates, 25 year rates are projected to determine potential

    I       ~~property loss under the full beach nourishment alternative.  For the 3,000

             feet nourishment project at North Forest Beach, a 1.0 meter/year erosion

             rate is assumed to better approximate more recent trends. Both alternatives

    5       ~~are considered in Table B-S.  To reflect time preference, potential loss is

             estimated in 10 year intervals as indicated in Table B-S. The value of

    1       ~~property loss for each of these intervals appears in column 2, while

    I       ~~the final column represents the present value of this loss discounted at

             a 4 percent rate. The present value of property loss at Hilton Head is

    5       ~~calculated to be $20.5 million under the first alternative and $1.0 million

            under the second alternative. It should be noted that in the first case

            almost half of this loss will occur even with beach nourishment as

            stabilization will occur only on the middle third of the beach while

            property losses are also calculated at the far northern and southern portions

            of the island. For this reason, the property benefits accruing under the
            first alternative are generous.

                                 Figure  B-11.  ZONES EMPLOYED FOR ASSESSING BEACH PROPERTY LOSS

                      I             ~~~~~~~~~~~~II

     Fourth               Third               Second               First
                  / ~ ~~~~~~~~~~~~~~~~~~~~~ \

    Quarter       I      Quarter             Quarter              Quarter                       Beach

                                                                                       AMENITY LOSS

                       RISK LOSS

                   BUILDING LOSS

                                                                             172

    TABLE B-4

    Distribution of Value on Lots - Hilton Head Island by Quarters of Lot*

         A. Value of Beach-Front Property
                     (Land Value)

             Beach To Property Edge                 .150
             1st Quarter of Lot                     .317
             2nd Quarter of Lot                     .333
             3rd Quarter of Lot                     .167
             4th Quarter of Lot                     .033

         B. Value of Non-Beach-Front Property
                     (Land Value)

             1st Quarter of Lot                     .357
             2nd Quarter of Lot                     .373
             3rd Quarter of Lot                     .207
             4th Quarter of Lot                     .063

         C.  Value of Buildings (By Quarter Lot)

             1st Quarter of Lot                     .150
             2nd Quarter of Lot                     .250
             3rd Quarter of Lot                     .400
             4th Quarter of Lot                     .200

    *All quarters numbered from the beach.

         TABLE B-5

                        Value of Property Loss on Hilton Head at Ten Year Intervals

                          11.4 Mile Project                              .57 Mile Project

    Interval            Value of           Present Value             Value of       Present Value
    In Years           Property Loss          of Loss           Property Loss          of Loss

    0-10               $ 6,875,357           $ 5,651,543           $  342,392      $  281,446
    11-20                10,392,712            5,767,956               517,557         287,244
    21-30                11,745,727            4,403,898               584,937         219,314
    31-40                11,774,722            2,979,006               586,381         148,354
    41-50                 9,714,739            1,661,221               483,794          82,728

    TOTAL               $50,501,257          $20,463,624            $2,514,962      $1,019,088

                  1                                                     ~~~~~~~~~~~~~~~~~~~174

    1       ~~Recreational Benefit

                  Visitation at Hilton Head is estimated by Claude Terry and Associates

    5        ~~(1980) to be 834,500, while growth rates are based on estimates by the

             Corps of Engineers (1974). Average visitor days per year for 10 year

             intervals are projected based upon these figures (Table B-6). Annual

    j       ~~visitation is translated to daily visitation on the same basis employed

             for Hunting Island. Peak day visitation is assumed to be 2.5 times weekday

             visitation, while Saturday and Sunday visitation are 1.5 and 1.75,

             respectively, times weekday activity.

     I           ~~~Carrying capacity at Hilton Head is estimated to be 90,288 users

    5       ~~per day based upon an average beach width of 150 feet and a beach length

             of 11.4 miles. With such a physical capacity, peak visitation is not ex-

    I       ~~pected to approach capacity during the projection period.  If past erosion

             rates continue., 5 of the 13 sections (stations) of the beach are expected

    t       ~~to be affected by erosion.  If all of these areas are completely removed

    1       ~~from recreational potential, the remaining carrying capacity of the island

             would still accomodate 55,562 visitors per day double the highest peak

             visitation estimate for the planning period. It seems unreasonable

             therefore, to justify beach nourishment in terms of recreational demand

    I       ~~for either of the project alternatives.

    5       ~~The Costs of Beach Stabilization

                  The cost of beach nourishment at Hilton Head is based on the supply

    5 ~~of 25,700 feet of feeder beach near Folly Inlet. Two sets of costs

             are considered. The lower cost estimate uses a $3 per cubic yard cost

    I ~~for the initial nourishment; the higher cost estimate uses a $6 per cubic

    1 ~~yard initial cost. Both costs scenarios assume a 5 yar renourishment cycle

             at 60 percent of the initial cost.. Based upon the cost estimates total cost

    3 ~~and present value of that cost are estimated for the 50 year planning period

             (Table B-8). The present value of costs is expected to range from $16.8

    f                                                                                 175

    I TABLI B-6

    IProjected Visitation and Recreational Value Accruing For Periodic Beach Nourishment
     at Hilton Head.

            5|~~~~ ~~1980-90    1990-2000    2000-10    2010-20    2020-30

     1. Visitation                       883,750    982,400        1,052,300  1,092,950  1,145,800

      2. Daily Visitation
         Weekdays (60)                     8,498       9,446          10,118      10,509      11,017
      g   ~Sats (12)                      12,747      14,169           15,177      15,764      16,526
            Suns (12)                    14,872      16,530           17,707      18,391      19,280
            Peak (2)                     21,245      23,615          25,295      26,273      27,543

      3. Annual Visitation
           with project                 883,750    982,400        1,052,300  1,092,950  1,145,800

    �4. Annual Visitation
           without project              883,750    982,400        1,052,300  1,092,950  1,145,800

    S5.  Differential                           0           0               0           0           0

     6.  Erosion Control
    6.   Benefit                               0           0                0           0           0

      7.  Total Benefit                                                                            0

    - - - M                                           - - - -  eM

        TABLE B-7

                      Costs of Beach Nourishment at Hilton Head Island

                              25,700 foot Project                             3,000 foot Project

       Year         At $3/yd3         At $6/yd                     At $3/yd3         At $6/yd3

          0          5,165,700          10,331,400                  603,000          1,206,000

          5          3,099,400           6,198,800                  361,800            723,600

         10          3,099,400           6,198,800                  361,800            723,600

        15          3,099,400           6,198,800                  361,800            723,600

        45          3,099,400           6,198,800                  361,800            723,600

       TOTAL       32,950,015          65,900,030                3,859,152          7,718,305

       Present
       Value of   16,843,668           33,678,336                1,972,754          3,945,508
       Costs

                    1                                                         ~~~~~~~~~~~~~~~~~~~177

    I        ~~to $33.4 million for the 25,700 foot project.  For the 3,000 foot project
             the present value of costs is expected to range from $2.0 to $3.9 million.

    I        ~~It is expected, at this time, that the lower cost scenario is more appropriate

             in both cases given sand availability and transport requirements.

             Summary of Benefits and Costs

                  Estimates of future benefit streams under both project alternatives

             are compared with both low cost and high cost scenarios to access the

    3        ~~feasibility of beach nourishment at Hilton Head.  For the 25,700

             foot alternative a favorable benefit/cost ration of 1.215 is found based

             upon the low cost scenario, while a ratio of 0.607 is found under the

             high cost assumption. It should be recalled that property estimates are

             slightly inflated as they reflect some areas at both ends of the island

    I        ~~outside of the project area.  Nevertheless, nourishment may be feasible

             along the middle third of Hilton Head Island if: 1) sand can be found and

    I        ~~transported at a low cost and 2) development pressures continue to increase

    5        ~~property values in this area.

                  For the 3,000 foot project considered at North Forest Beach, unfavorable

    5        ~~benefit/cost ratios of 0.517 and 0.258 are estimated.  Given the value of

                ~q~:iesin this stretch of the beach, beach nourishment does not seem

    I        ~~to be a reasonable alternative.

     5            ~~~Should beach nourishment be considered at Hilton Head, the distribution

             of costs among public and private parties will be an important consideration.

    5        ~~The principle criteria for justifying such a project must rest with  property

             values in the affected area as no recreational benefit is anticipated due

    I        ~~to an excess of capacity forecast over the project period.  Although much

    1        ~~of the area has been developed to date, new development and reconstruction

             should attempt to locate in such a way as to minimize the potential loss

                                                                          177a

    TABLE B- 8

         Summary of Benefits and Costs of Beach Nourishment at Hilton
         Head Island in Present Dollar Values

    Alternative I: 25,700 foot Project

    Item                   Benefit            Low Cost            High Cost

    Property Loss         $20,463,624

    Recreational                     0
       Value

    Project Cost                             $16,843,668         $33,687,336

    TOTALS                $20,463,624        $16,843,668         $33,687,336

    Benefit/Cost Ratio                             1.215              0.607

    Alternative II:  3,000 foot Project

    Property Loss         $ 1,019,088

    Recreational
       Value                        0

    Project Cost                             $ 1,972,754         $ 3,945,508

    TOTALS                $ 1,019,088        $ 1,972,754          $ 3,945,508

    Benefit/Cost Ratio                            0.517               0.258

    1
    I
               due to long-term erosional trends. The most effective way of limiting
               loss potential is to insist upon reasonable setback lines, therefore
               allowing for long-run shifts in the beach profile.

    1
    I
    I
    I
    I
    U
    I
    1
    I
    5
    I
    I
    I
    I
    I

                                       CASE C: PAWLEYS ISLAND

           I                               ~~~~~~~~~Beach Morphology

     3            ~~~~Pawleys Island is located at the southern end of arcuate strand and

              is separated from Pleistocene shoreline deposits by a narrow marsh sys-

    I        ~~tem.  The inlets that border Pawleys are small, shallow, and transitional,

              showing the effects of both wave and tidal processes. The spring tidal

              range and high energy wave climate tend to keep sand shoals associated

    j        ~~with Pawleys and Midway Inlets close to the inlet throat where they under-

              go sediment exchange with adjacent beaches.

    3        ~~Long-Term Beach Changes

                   Shoreline configurations compiled from the 1937, 1957 and 1973

              aerial photo sets show that Pawleys Island has been'relatively stable a-
    3         ~~long the central section over the past 40 years (Fig. C-l.).  Maximum

              change in shoreline position recorded from aerial photos and historical

    5        ~~charts at fixed reference points is on the order of + 100 meters (Fig. C-i).

              The general trend along the northern half of the island is depositional.

    1        ~~The southern half of the island has been stable to moderately erosional.

    I        ~~These trends are subject to inlet fluctuation.

                   The island is relatively small (5-6 km.) and the small bordering in-

    5        ~~lets are subject to abrupt and rapid morphologic change due to wave and

              storm effects. Therefore, it is probable that depositional - erosional

    I        ~~trends are controlled, in large part, by sand bypassing processes at Mid-

    I        ~~way and Pawleys Inlets.  Inlet - related changes are most apparent

              immediately adjacent to the inlets, but changes along the control part of

    3        ~~the island are likely to be a function of addition or removal of sand

              from the littoral system by inlet sand bypassing.

                                                                     179

                       IY    INLET
                                                        /

        I~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~i

                                           4

                                                  +200 P'3
                                   0 1872 19421973
                                    . /5
                                                  -200
                                   /
                                  /

                                               I   +200 P.4
                                                -oLu
                              LC,,~V  '~-200

                                                  +200 .-5

                                                      2 1942 1973
                                                 -200

                      PAWLEYS INLET ---------- 1939

                 , /                          -- 1957

                , ! 1973
    I~~~~~~~~~~~~~~~~~~~~I
                                                    _ KM
                               0    .5     1            2

              FigurEC-1. Changes in shoreline position on Pawleys Island
                based on aerial photo surveys from 1939 to 1973. Numbers
                (3, 4 and 5) indicate fixed reference points for graphed
                shoreline data.  PWI indicates location of single beach
                profile.

                    1                                                          ~~~~~~~~~~~~~~~~~~~~~180

     5            ~~~~The area of concentration for this study has been Midway Inlet, be-

              cause changes there, though paralleling the evolution of Pawleys Inlet,

              have been more complex. Change is, in part, related to man-made altera-
    3        ~~tions of the back-barrier salt-marsh system.  Two causeways built across

              the marsh to Pawleys Island have divided the once continuous tidal drain-

    5        ~~age network between Pawleys Inlet and Midway Inlef into nearby separate

              systems (Domeracki et al., 1980). Drainage to both systems has been re-

    I        ~~duced, but the larger part of the tidal prism is exchanged through

    I        ~~Midway Inlet.  Between 1939 and 1950, Midway Inlet migrated 400 m to the

              south causing severe erosion of beach property at the north end of Paw-

    5        ~~leys Island.  A stone jetty was constructed in 1952 in an attempt to

              stabilize the inlet and prevent further beach loss (Fig. C-2 ). The

    I        ~~position of Midway Inlet shifted north by 1957, an apparent result of

    5        ~~spit breaching during Hurricane Hazel.  The north end of Pawleys Island

              began an accretional episode, whereas beaches north of the inlet were

    5        ~~eroded significantly (Figs. C-1 and C-2).  From 1957 to 1963, Midway

              cut a more southerly route through the inlet shoal system, and the north

    I        ~~end of Pawleys Island continued in a depositional trend, probably through

    I        ~~swash-bar accretion around the stone jetty.  By 1973, Midway Inlet was

              forced into a more northerly position by a spit-like extension at the

    3        ~~north end of Pawleys Island.  The north end of the island was cut back

              significantly by 1979. As a result of Hurricane David in September, 1979,

    I        ~~the main ebb channel broke through surrounding shoals along a curved

    �        ~~route toward the beach and the north end of the island suffered abrupt

             and severe erosion (Fig. C-2). This erosional trend began to reverse by

             May, 1980, when the inlet channel breached the shoals along a more seaward

             route (Fig. C-2). The results of this more normal configuration include

                   ~-~ !;"t'      1950              -                         1963

                                  1952                                        1973

                                  1957                                        1979

                                                              MAY  1980

    FigureC-2 Geomorphic changes at Midway Inlet since 1950 (after Domeracki
      et al.. 1980),
                                                                                                     0o

                                                                    182

    the apparent onshore migration of swash-bar type sand bodies at the north

    end of Pawleys Island, at least partially restoring lost beach property.

    Short-Term Changes in Beach Morphology

         Profile data is presently available for only one station on Pawleys

    Island (Fig. C-1J. The profile measured at monthly intervals over a two-

    year period shows beach morphology and volumetric changes typical of the

    central part of Pawleys Island.  Overall beach morphology is similar to

    other arcuate strand beaches. The beach profile is concave up (Fig. C-3 )

    and the beachface dips seaward at 1 to 1.SD, which is slightly steeper

    than on beaches south of the arcuate strand. This slope is a function of

    coarser sands available from nearby Pleistocene sources.

         No distinct seasonal trends in beach morphology (Figs. C-3 and C-4)

    or volumetric changes were seen among the data collected during the two-

    year survey at the single profile station on Pawleys Island. Net

    volumetric change at this station was slightly erosional, but no defi-

    nite trend can be assumed from the data (Fig. C-4). Several of the

    recorded monthly changes in beach volume were equal to or greater in

    magnitude than the two-year volumetric change.

                              Alternative Solutions

         The specific concentration of alternative solutions for Pawleys

    Island has been the north end of the island, adjacent to Midway Inlet, due

    to the complexity of the problems of inlet stabilization.  In addition

    to a no action response, inlet stabilization and engineering alternatives

    of using a bulkhead, revetment, or terminal groin have been considered.

    No Action

         If no action is taken, the present erosion/accretion cycle will re-

    peat itself periodically.  In addition to this response of inlet

    1I                                                                                                                                183

                                                                                               PWOI       6700 a      74

                          1~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~o -  2          327
                                                                                                          1009 I 15  7 6
                                              La

                                                0U.00   20. 00  40.00 Gil.00  80.0 100   0 O.00  I0100   i14 . Oa     2do.o  00~o
                                                                              DISTANCE (IN
    I                                                                                           W.00   Pb.PD  9b.PD ~b.OO ~b.OO  lbD.00  liOIOO   W230.00   13O.OO   2bo.OF    3L78

                                                                                                    ~~t  1023 1 3 a  76

    I

                                                '    g0.00   f0.00  40.8o ob.oo  80.00  100.00  120.00  140.00  10o.00  10.0Do 20.00o
                                                                              DISTAlCE (M]
                                                                                               PWOI1           6 a    74
                                               I  .                                                      1748 15 8  78
    I

                                                      Lao                   ~~~~NET CHANGE

                                                0O.00   24. 00   O.0   00G.00  0b.00  a.0  Oa0.00  i1o.oo  140.00  ]b.O o  2b00o.00
                                                                              OISTAHCE (M)

                                      Figure -C-.3.Comparison of selected beach profiles between
                                          1974 and 1976 at Pawleys Island beach profile station
    I                                        ;W

    I.

     40                                       4
    a" 0                                              .XPW1

           ~~~g~~~~~~~      I                             I

          -60

          -40

                    1974                  1975                       1976

    Figure C-4.Volumetric change in cubic meters per meter of beach at beach profile
      station PWI,

                                                                              185

              availability the beach is also affected by severe storms and to a lesser

    I        ~~extent sea level rise, both causing erosion.  Beach scrarping and dune

              destruction will occur as well as potential property damage in particu-

              larl~y vulnerable areas due to shallow setbacks and positions relative to

    3        ~~Midway Inlet.  The costs of the no action alternative would be limited to

              the value of beach, dunes and homes in the immediate area.

    I        ~~Bulkhead

                   A distance of 1000 feet (305 m) has been selected as the project

              length, providing limited protection to the most seriously threatened

    5        ~~property.  A bulkhead will prevent shoreline retreat as long as it is

              designed t9 withstand storm attack. It is recognized, however, that these

    I        ~~walls may result in accelerated scour on the beach during storms and, thus,

              may tend to reduce beach width.

     I            ~~~~The proposed unit would be of precast, steel reinforced concrete, ton-

    5         ~~gue and grooved.  Each panel measures 3 in. x 12 x 4.5 ft (.076 x 3.7 x 1.4 m)

              and would be driven 8 ft (2.4 m) into the ground. Tie backs on 9 ft

    3         ~~(2.7 m) centers would be anchored in a backfilled dune landward of the

              bulkhead. After the structure is in place, a continuous concrete cap

    I         ~~would be constructed on top.  Filter cloth would be used at each of the

    3         ~~panel joints to limit washout during periods of seaward drainage.  Toe

              protection using stone is placed in front to an elevation of 2 ft (.61 m)

    I         ~~on a I to 2 slope (Fig. C-5).

    "mm  m m"M MM" m  m m                        m m    m m              m  m m       m-  -         mm

                     EXISTING SOIL            CONCRETE  CAP

                                        * ~CONCRETE SLAB
           CONCRETE                            WITH REINFORCING
           DEADMAN

                                            \KIRA                       BEACH

                                  Fig C-5. Proposed Bulkhead -
                                           Pawleys Island

                                                                  187

                         TABLE C-1 - Bulkhead Cost

       a. bulkhead

           1100 ft. (including 100 ft. flanks)

           at $65 per feet                                 $71,500

       b.  riprap stone, 180 tons                            8,100

       c.  engineering, supervision                          7,310

                                           Total         $86,910

       This form of shoreline stabilization is semi-permanent, subject to

    failure from severe storm attack or extreme shoreline retreat.

    Riprap

       An alternative to the bulkhead is stone or rubble placed at the base

    of the dune line,(Fig. C-6). If necessary, the dune is first rebuilt

    and then graded to a 1 on 2 slope.  Large coarse stone is placed on a bed

    of finer material.  As in the case of bulkheads, riprap is designed as

    a barrier to hold a reach of shoreline. Erosion seaward is not controlled

    by this scheme, and, in fact, may be accelerated due to a lack of beach

    replenishment from dune erosion. As with the bulkhead this approach is

    a semi-permanent solution.

                          TABLE C-2 - Riprap Cost

       a.  1000 ft @2.5 ton/ft, $45/ton                   $112,500

       b.  engineering, supervision                         11,250

                                           Total        $123,750

    Terminal Groin

       A terminal groin at the extreme north end of the study area (adja-

    cent to the inlet) would reduce the impact of inlet migration on the

    beach.  The groin would act as a large sediment trap, collecting the

    mm-                             -                           -  MM m/m M m    MM m m   - m

                                                     STONE RIPRAP

                            GRAVEL   R'"'
                            BLANKET
                                                                                      BEACH
                                                                                  ,,,_,,,�. .  :    . -:,  .  . ,

                                                                                                ,~~�:.t~o .

                           Fig.C-6. Proposed Riprap Profile - Pawleys Island

                    1                                                           ~~~~~~~~~~~~~~~~~~~~~189

               sand which tends to be carried north into the inlet. The groin would

               also serve to control the inlet, reducing its tendency to change

    5          ~~~alignment.  It should be noted that a terminal groin, while similar

               to regular groins in that it is perpendicular to the beach face, is

    3          ~~~both longer and more massive than the former.  Figure C-7 illustrates

               the position and dimensions of the proposed groin. The unit would be

               constructed of large stone rubble with a 5 ft (1.5 m) width at the top.
        3                        ~~~~~~~TABLE C-3 - Terminal Groin Cost

                  a.  stone (estimate 13,900 tons)                    $625,500

    5            ~~~b.  engineering, supervision and contingencies    165,757

    U          ~~~Inlet Stabilization          T        t l $9,5

    3            ~~~Periodic dredging of Midway Inlet can be used as a shoreline protec-

               tion alternative. Dredging could be undertaken whenever the main axis

    *          ~~~has shifted to the south and erosion is taking place in the project

               area. This alternative would yield two positive results:

    3            ~~~~1.  the main axis of the inlet would be returned to a central

     5               ~~~~~location, reducing the erosion at the adjacent shoreline, and

                  2. the dredged material could serve as beach nourishment to fill

     3               ~~~~~the eroded section.

              Such dredging would be a temporary solution. The frequency required

    I          ~~~would depend upon the occurrence of large storms, changes on the

    5          ~~~shoreline north of the inlet, and changes in the interior estuary.

                                     TABLE C-4 - Dredging Cost

    3          ~~~Note:  Total volume for a single dredging operation was assumed to be
                                           3
                       35,1000 cu yds (27 km ). Unit costs ranged from $2.50 to $4.00 per

      5               ~~~~yard, and engineering, supervision and contingencies were added at

                                         190

                GROIN

             I~ ~~~'~--- ARMOR VARIES
                                ERMOR
                                  STONE

          CORE STONE

    Fig. C-7- Proposed Terminal Groin
           and Position - Pawleys Island

                  10 percent and 15 percent, respectively.

                  Dredging                                            $110,700 -_$1173 100
         5                           ~~~~~~~~Cost-Benefit Analysis

                  Of the sites considered, Pawleys Island most clearly typifies the

    3          ~~~traditional family resort with rustic beach houses reflecting its

               historic past. Although an 54 unit condominium complex was completed

    U          ~~~in 1972, the beaches at Pawleys remain less crowded than beaches further

    3          ~~~north along the Grand Strand.  Under present land-use conditions, the

               more immediate erosion-related problem at Pawleys Island appears to be

    3         ~~~the potential for property loss.  Short-term erosional trends have caused

               considerable concern among property owners for which various solutions

    I         ~~~have been suggested.  The analysis that follows considers the feasibility

    3         ~~~of employing the aforementioned options to alleviate potential loss of

               recreation and property.

    *         ~~~Property Loss

                  Although the older residences at Pawleys Island are generally built

    I         ~~~well behind the dune line, continued erosional trends could result in

    5         ~~~property loss particularly at the north end of the island.  To estimate

               the potential for such loss, county appraisals completed in 1973 were

    3         ~~~gathered for all properties on the island.  Based upon recoreded market

               sales since that time, a yearly appreciation rate of 13 percent was

    I         ~~~estimated to derive a 1980 estimate.  As most of this property had been

    5         ~~~developed previously, land and building values were difficult to separate.

               Therefore, land and building estimates were combined, and lot values were

    3         ~~~disaggregated in the manner indicated in Table C-S as follows.

                                                                    192

    TABLE C-5

    Distribution of Property values'at Pawleys Island by 'Lot Section.

                                                    Percentage
    Section                                           of Total

     First Quarter                                       .200

     Second Quarter                                      .325

     Third Quarter                                       .383

     Fourth Quarter                                      .092

    TOTAL                                               1.000

         The allocation of land value differs slightly from that used at Hil-

    ton Head and Myrtle Beach as private property lines at Pawleys are drawn

    from the mean high water mark. Therefore, the beach area with its amenity

    value lies within the first quarter. Building values are distributed as

    determined by the location of structures on oceanfront lots.  Once again

    building value is assumed to be lost when the high water mark surpasses

    the foundation of the structure.

         The estimated loss and time interval at which portions of the pro-

    perty are lost is based upon historical erosion rates along the island

    as discussed above.  Table C-6 lists the total amount of property to be

    lost if 100 year erosional trends continue. As the potential loss pre-

    vented by erosion control occurs as a benefit stream over time, the value

    of loss in constant dollars is discounted at a 4 percent rate. It is es-

    timated that the present value in terms of property loss prevented by

    effective erosion control measures will be $2,332,342.

                                                                     193

    TABLE C-6

    Projected property loss and present value of property loss resulting from
    beach erosion at Pawleys Island.*
                                        Total                   Present Value
    Section                          Property Loss              Of Property Loss

     First Quarter                   $5,025,889                  $1,822,259

     Second Quarter                   2,954,098                      446,595

     Third Quarter                      376,176                       60,900

     Fourth Quarter                      18,357                        2,588

    Total Present Value              $8,374,520                   $2,332,342

     *For Pawley's Island, property lines extend down to the High Water Mark--
           for this reason, the first quarter at Pawley's Island incorporates
           the beach area, unlike the Hilton Head Island and Myrtle Beach
           studies.

                    1                                                          ~~~~~~~~~~~~~~~~~~~~~194

               Recreational Benefit

     I             ~~~~Figures by the Waccamaw Regional Planning Commission (1978) and

               projections by Hartzog, Lader, and Richards (1974) estimated peak

               visitation at Pawleys Island to be 4,500 and 4,430, respectively in

    1         ~~~1977.  The mean for these two studies projected a growth rate in visitation

               of 10 percent per decade through the end of the century. Applying this

    3         ~~~rate of growth to the approximate peak visitation for 1980 as estimated

               by the Waccamaw Regional Planning Commission, peak visitation is

               projected for the planning period (Table C-7). As only peak visitation

    3         ~~~is projected, weekday and weekend activity is estimated using the same

               weights employed at Hunting Island. Peak usage is assumed to be 2.5 times

               weekday usage, while Saturday and Sunday usage is assumed to be 1.5 and

               1.75 times weekday activity, respectively. Seasonal visitation disagre-

               gated in this manner is shown in Item 2 of Table C-7.
     1             ~~~~The average dry sand beach at Pawleys Island is estimated to be 40 M

               wide (MHW) and 2.5 miles in length. Based upon an average space require-

    3         ~~~ment of 100 square feet and a turnover rate of one, the present carrying

               capacity of the beach is 17,318 users per day. If recent erosional trends

    U         ~~~continue, the maximum loss of dry beach area would be 664,187 sq. ft.

    3         ~~~The remaining beach would still provide a carrying capacity of 10,677

               users per day, sufficient to accomodate peak use over the planning period.

    3         ~~~As a result, no recreational benefit is estimated for any of the measures

               taken to stabilize the beach.

    *         ~~~The Cost of Alternatives

     3             ~~~~With the exception of the no action solution, the alternatives proposed

               involve an initial outlay during project construction. It is difficult to

                                                                                195

    TABLE C-7

    Projected Visitation and Recreational Value Accruing For Periodic Beach Nourishment
    at Pawleys Island.

                                       1980-90    1990-1000    2000-10    2010-20    2020-30

    1.  Visitation                    $204,256   $224,640       $247,104   $271,572   $299,000

    2.  Daily Visitation
         Weekdays (60)                    1,964      2,160         2,376       2,613      2,875
          Sats (12)                      2,946       3,240         3,564       3,920      4,313
          Suns (12)                      3,437       3,780         4,158      4,573       5,031
          Peak (2)                       4,909       5,399         5,939      6,533       7,187

    3.  Annual Visitation
         with project                  204,256    224,640        247,104    271,572    299,000

    4. Annual Visitation
         without project               204,256    224,640        247,104    271,572    299,000

    5.  Differential                          0           0             0          0           0

    6. Erosion Control
         Benefit                              0          0             0           0          0

    7.  Total Benefit                                                                  $       0

                    3                                                          ~~~~~~~~~~~~~~~~~~~~~196

    3        ~~predict life expectency of any of these alternatives without further in-

              formation, yet it is known that none of these solutions will be permanent.

              A reasonable assumption is that the structural solutions will require re-

    3        ~~placement every 20 years.  As inlet stabilization will be required each

              time a storm breaches the inlet significantly altering sediment transport

              to the north end of the island, it is assumed that the stabilization of
    3        ~~Midway Inlet will be required every 10 years.  Based on these assumptions,

              the cost projections are made for each of the alternatives   (Table C-8).

    3        ~~The terminal groin is estimated by the most expensive alternative ;costing

              considerably more than the other solutions at   present value terms.

    U        ~~Summary of Benefits and Costs

     3            ~~~~Based on the estimated present value of costs and benefits accruing

              over the project period, each of the alternatives offers a favorable bene-

    3        ~~fit per cost ratio with the construction of a terminal groin appearing

              to offer only marginally favorable conditions (Table C-9). The construc-.

    I        ~~tion of a 1000 foot bulkhead to maintain property appears to offer the

    3        ~~most favorable alternative, yet these figures require some clarification

              as the relative effectiveness of each of these alternatives cannot ade-.

    3        ~~quately be determined given present information.

                   Without inlet stabilization, localized erosion may shift as the in-

    U        ~~let changes direction and sand transport patterns are altered.  Both the

    3        ~~bulkhead and riprap would require extension or construction at another

              location. Wrap around effects on adjacent properties might cause a

    I        ~~leapfrogging effect along the beach.  Finally, although beach capacity

             has not been reached, accelerated erosion of public beaches which might

    I        ~~result with either of the retainer structures would not be without cost

    3        ~~in terms of both recreation and amenity.

                                                                      197

    TABLE C-8

    Projected Costs and Present Values of These Costs for Each of Four
    Erosion Control Alternatives for Pawleys Island.

                              Alternative 1:  Bulkhead

                                                           Present Value
    Year                          Cost                         of Cost

      0                          $ 80,410                   $ 80,410

     10

    20                            80,410                     36,667

     30

    40                            40,205                      5,709

     50
                                                          $122,786

                              Alternative 2: Riprap
                                                           Present Value
    Year                         Cost                          of Cost

      0                          $123,750                   $123,750

     10

     20                           123,750                     56,430

     30

    40                            61,875                      8,786

     50
                                                          $188,966

                                                                            198

    TABLE 8 Con't.

                               Alternative 3: Terminal Groin

                                                               Present Value
    Year                               Cost                        of Cost

      0                               $791,257                  $  791,257

     10

     20                                791,257                     360,813

     30

     40                                395,629                      56,179

     50
                                                               $1,208,249

                            Alternative 4:  Inlet Stabilization

                                                               Present Value
    Year                               Cost                        of Cost

      0                               $117,100                     117,100

     10                                117,100                      79,160

     20                                117,100                      53,398

     30                                117,100                      36,067

     40                                117,100                       16,628

    50
                                                               $ 301,353

                                                                            199

    TABLE C-9

    Summary of Benefits and Costs of Shoreline Protection Alternatives at Pawleys
    Island.

                              Property          Recreation              Benefit Cost
                               Benefit           Benefit       Cost          Ratio

    Bulkhead                $2,332,342                    0  $  122,786       18.99

    Riprap                   2,332,342                    0      188,966      12.34

    Terminal Groin           2,332,342                    0  $1,208,249        1.93

    Inlet Stabilization      2,332,342                    0      301,353      7.73

                                          CASE D: Myrtle Beach

           3                               ~~~~~~~~~~Beach Morphology

                    Myrtle Beach is the only mainland-type beach among the four areas

    I          ~~~considered in this survey.  The tidal range is significantly lower than

    3          ~~~along the barrier island section to the south, averaging 170 cm at

               spring tide. The section of South Carolina that includes Myrtle Beach

    3          ~~~is similar to other microtidal shorelines tending to be wave-dominated

               and cut by few major inlets.

     I              ~~~~Similar to other sections of the arcuate strand, sands along Myrtle

    3          ~~~Beach are somewhat coarser in mean grain size than along barrier island

               sections and finer than beach sands of the cuspate delta zone. It is

    3          ~~~likely that erosion of Pleistocene beach-ridge sands of the Myrtle Beach

               Formation just landward of the active modern beach serves as a source

    I          ~~~for the coarser material.  In addition to erosion of Pleistocene beach-

    1          ~~~ridge sands, outcropping of loosely consolidated, calcareous sandstone

               at several locations also effects the stability of the Myrtle Beach

    3          ~~~shorelin(-, (Dunbar, 1964).

                    The existing data base for shoreline changes along Myrtle Beach in-

    U          ~~~cludes sets of low level aerial photographs, hydrographic surveys and

               short-term beach profile surveys. Aerial photo sets from which shoreline

               positions can be determined are available from 1948, 1952, 1958, 1965,

    5          ~~~and 1973.  Longer term data at more widely-spaced intervals are availa-

               ble from hydrographic surveys completed for the Myrtle Beach area in

    1          ~~~1878, 1925 and 1972.  The resulting nautical charts include the position

               of the low water shoreline. Data concerning short-term changes in beach

                                                                   201

    morphology and short-term depositional-erosional cycles are available

    from four beach profile stations within Myrtle Beach proper.

    Long-Term Trends

         Analysis of shoreline changes for a six kilometer section of Myrtle

    Beach proper is based on the hydrographic and aerial photo surveys between

    1878 and 1973 relative to six controlled points (Fig. D-I; Table D-l),

    indicating a distinct erosional trend from 1878 through 1940. Mrtle

    Beach was not uniformly erosional, however.  Erosion rates increased to

    the south (Fig. D-l; Table D-1) and zero net change was recorded relative

    to the two northernmost control points (Table D-l). From 1948 through 1973,

    erosional rates slowed or reversed (Fig. D-l). The shoreline was most

    stable between 1958 and 1973 compared with earlier periods. During this

    time, the shoreline at all six control points underwent zero net change

    or was moderately accretional (Table D-1).

         Overall, the northern half of Myrtle Beach seems to be more resistant

    to erosional episodes. This trend holds true for both shorter-term and

    longer-term data. Similar to Pawleys Island, net change and rates of

    change in shoreline position along Myrtle Beach are an order of magnitude

    less than changes evident from the case studies of Hilton Head Island and

    Hunting Island. The relative stability of arcuate strand beaches is, in

    part, related to proximity of Pleistocene sediment sources and outcropping

    of resistant units along the beach. Lower rates of change are also related

    to the lack of large inlet complexes within the arcuate strand.  The abrupt

    and large volumetric changes common to beaches in the barrier island sections

    of South Carolina where sand exchange takes place between inlet shoals and

    adjacent beaches are not to be expected where large inlet complexes do

    not exist.

                                                                   202

                                      I  iv

                                                                 f   -200   1973

                                                                 +200 M-2
                                                                   01878 195?173

                                                                -200   ..73

                         /~~~~~~~~K/ M
                                                                   878 1957

                                               0     .5     1           2

    Figure D-1. Depositional-erosional trends along Myrtle Beach compiled from
         vertical aerial photographs and historical charts,

    TABLE D-1       Beach Profiles at Myrtle Beach, 1878-1973.

    Reference           Change           Change         Change         Change         Change         Change
      Point            1878-1940        1940-48        1948-52        1952-58        1958-63        1963-73

      M 1                  0              - 6            - 7            -11             0             34

      M 2                  0              -10             10            -29             0             21

      M 3               - 57                0              0            -17             0              0

      M 4               -169                0             11            -29             0              0

      M 5               - 80              -30            - 7              0            14              0

      M 6               -195              -50              9            -10             0              0

                                                                  204

    Short-Term Shoreline Changes

         The four profile stations along Myrtle Beach are spaced 1.5 to 2.5 km

    apart and provide a survey of morphology variation within this area

    (Fig. D-2).  Profiles measured along Myrtle Beach differ somewhat than

    the convave-upward profile typical of (Figs. D-3, D-4, D-5 and D-6) other

    arcuate strand beaches.  Instead, Myrtle Beach is characterized by a re-

    latively straight shoreface that dips seaward at slopes of up to 2 degrees.

    The steeply-dipping foreshore is a function of the coarser sands found in

    the beach compared with areas further to the south.  Mean sand size

    ranges from 0.25 to 0.35 mm (medium sand); whereas, mean grain size of

    beach sands comprising barriers south of the cuspate delta region range

    from 0.15 to 0.10 mm (fine to very fine sand).

         The low tide beach is relatively narrow in the Myrtle Beach vicinity

    compared with finer grained flatter barrier island beaches.  Average width

    is approximately 100 m. at mean low water. Ridge and runnel topography

    tends to be of low amplitude and activity is more frequent in the late

    spring and summer months at the end of erosional and the beginning of

    depositional beach cycles.

         Volumetric changes calculated from profile data show more distinct

    seasonal trends than beaches in the other case study areas to the south

    (Fig. D-7).  Similar changes in beach profile occurred along the entire

    6 km section of Myrtle Beach included within the profile network. This

    may be due, in part, to the lack of inlet-related changes that mask seasonal

    or cyclic trends. Depositional cycles occurred from late summer to early

    winter; whereas, erosional cycles occurred from late winter through spring.

    Depositional cycles at the southernmost station, SP1 (Fig. D-7) lagged 1

     I
                                                                205
    I
    I
    1
    I

    I

    IMB

    I

            ~~~~~1~~~~~~~~~~~~~SP

    I
    I
    I
    I
               Figure D-2.   Location of Myrtle Beach profile stations,  1974 to 1976.

    I
    I

                                                                                                                                206

                                                                                        OFO1           143 29  9   74

                                        1530 1                                                                               1 10  74
                                     2g

                                      o=:

                                       '0.CD    2b. 00 I.0 b. 00    6b.DO    b.8O  0 .0       20.00 Do   I     D120.00 00.00   2bo.00
                                                                       OISTANCE IM1
                                                                                         OFOI         1420  16S       75
                                       O                                                                         1249   14  12  74

    IO                                        3
                                        '0.00    2b.00   ob.oo   36b.0 O    sb. O     bo00    i0 1 o. oo   1io.00   b6. oo D o.oD     bo0.oo
                                                                       OISTANCE (Ml
                                                                                         OF beach      sis from selected dates 75  between
                                       Septer1500  26  7   75

                                      z

                                                    I~~~~~ ~OFO ls 9 7

                                      o,

                                     tu=.

                                       '0.00    lb.oo   ab.oo   36b.00    b.0o    Ib.oo �     b.oDo  1b.oo   sb.oo    9b.Io    ,bo. oo

    I~   ~

                                                                                                                                                     207

                                                                                                               MeOQI        1600  s  8   74
                                                          o                                                                    1250  i6  9   74

                                                          9.
                                                          _a

                                                         I
                                                           ' O0.0 0 a    o .g  o 0,  O.a 30to    b.oo    bo.oo    lo00    12 U.    0  00 t0 o I o  i0. '10  200. 00

                                                                                                               MBO.1 5I 21 31  1   75
                                                                          1S~~~~~~~~~~ 1~350 i2  2   75

                                                          �                                                                       0
                                                        g-

                                                         _i                                                                     IqS I  _

                                                          0.00 D    .cbo   .ID0O.  zbz  40.00    00 ;.11   l2i.0oo   .40.00  ;10.00   1 00eo   2UO O.

                                                          :'gd                                          .i...4   114                         76

                                                        0,

                                                                                              NET CHANGE
                                                             ..---...,T ..c                      .2..c                   '       60 O D NI
                                                          0 �c    211.10  b.1.     6o0000                    1100   4O0'00   :6L.00 00 40 00  ibc (o
                                                                  I7~~ 1                                                            1 4013ONI�   IMI

                                  Figure D-4. Comparison of beach profiles from selected dates between

                                           August, 1974 and August, 1976 at station NB-1.

    1

                                                                                                                                                                             208

                                                                                                                             RCOI           1123  29  9    74
                                                                S                                                                                  iS109  I9 10  74

                                                              ZI

                                                              r.;

                                                                'o.DO     lb. D     zb.oD    3b 00  Db.oo    sb.00o           b. 0D .bOO    b0. 00    3b9  D          ;0  00
                                                                                                       D0STANCE In1
                                                                                                                            RCOi           913   22  2    75

                  ~~I                                              8~~~~                                                                               iO01 8 3 75

                                                                                                                                           940  19   10  75
                                                             i0o

    -I                                                              >
                                                               'o.o       I. b.o           DOb.Oc    3b.co  4b.C     5b.2o  s: oo     Ib.oD    sb oo    3b.Do0    ib.oo
                                                                                                       OlSTANCE  1(I'
                                                                                                                            RCOI           1435  25        7 75

                                                                           September, 1974 and October, 1915qa 25 s 75
                                                             L0
                                                             w,
                                                              -o

                                                                O.DoO      Ib.00    2b.00    3b.o00       b.oo     sb oo s' oo  :b.0o              b0.0o    30.00     I OD.
                                                                                                       OiSTRN,.E  IMI
                                                                                                                             RCO]I           338  21  9    75
                                                               S                                                                                  i33q  19 a0  75

      I                                                              .

      I

                                                                                                                                          209

                 5~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~I~NEII~                                 140        41J I".     I'"0   PbI

                                                                                               SPO01      951  8  2  75
                        :1,                0                                                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~937  8 a    75

                                                                             DISTANCE IMI

                                                                                                     SF01  101 29 9  7 q

                   3                                                           ~~~~~~~~~~~~NET CHANGE

                                            D.0    0  0.0   4-0.0 O    60.,00  -60.00  -1aO'O  00 .00  40.00  140.00  - 46 0.00  "140.00  2,00.a00

                  I                                                       ~~~~~~~~~~~~~~~~~~~DISTANCE (Ml

    5               ~~Figure D-6.  Comparison of beach profiles from selected dates between

                                September, 1974 and October, 1975 at station SP-1.

                                                                          210

                          60I
                                                         .             OF1

                          -60-         5
                           o0         MI

                              tYT II                        I    I I I I  I I I

    I                    UJ  20

                         -40-

                         60 -

                        40

                         0 -          l

                          20 i-   Il

                          I             I III Ii         I    I I I I I
                          0 -

                         -20-

                          -40  '       I    '     j    !,,  I    I    I   I   I
                             A SOND J F MAM  J A SON D JF MAM J J ASO

                    Figure D-7. Volumetric change in cibic meters per meter of beach between
                        survey dates at Myrtle beach stations QF-1, MB-i, RC-1 and SP-1.

                    �                                                           ~~~~~~~~~~~~~~~~~~~~~211

               to 2 months behind depositional episodes at the three other profile loca-

               tions to the north. This may have been the result of a packet of

               sediment moving south within the southerly net littoral drift system in

    I          ~~~this area.

     5              ~~~~Volumetric beach changes recorded were smaller and less abrupt than

               recorded at the other case study sites. This reflects the relative sta-

    3         ~~~bility and lack of inlet-influenced changes along Myrtle Beach.  Net

               change recorded at all four profile stations over the I to 2-year study

    1         ~~~was depositional.  Monthly changes in volume at all four profile locations

               were similar in magnitude or greater than net change over the'entire

               study period.

                    it can be concluded that the shoreline position of Myrtle Beach was

               relatively stable at the time of the 1974-76 profile study. The beach

    I         ~~~here was not subject to large, abrupt changes, but showed seasonal or

    5         ~~~at least cyclic depositional-erosional episodes.

                                          Engineering Solutions

     I             ~~~~Myrtle Beach is a relatively stable region, with beach erosion pri-

               marily a result of storms. Hurricane David caused significant erosion, as

    I         ~~~did a recent extratropical event.  During these periods of large storm

               tides and waves, the beach sand is apparently carried seaward to a depth

               where post-storm waves are unable to return it to the beach. Erosion pro-

    5         ~~~tection could require the construction of offshore breakwaters  designed to

               reduce the magnitude of the wave heights reaching the beach. Alternatively,

    I         ~~~the beach can be resupplied or nourished on a periodic basis as dictated by

               the magnitude and frequency of storms.

                    There are two secondary factors which also contribute to the erosion

                                                                 212

    problem at Myrtle Beach.  The storm water outfalls on the beach clearly

    result in local scour during periods of heavy rainfall.  In addition,

    the present pattern of discontinous bulkheads impacts the beach. While

    neither of these problems are considered in the present review, they are

    important in understanding the causes of erosion on Myrtle Beach. The

    outfalls should be removed, and the bulkhead should be a continous,

    uniform barrier.

    Beach Nourishment

         The periodic replacement of beach sand by nourishment is a well recog-

    nized non-structural erosion control procedure. The rebuilt beach

    provides both protection (by absorbing wave attack) and recreation.  The

    dimensions of the nourished beach are determined by the degree of protec-

    tion required, space requirements for bathers, and natural equilibrium

    contours.  Many beach nourishment projects include a barrier dune intended

    to act as a dike or levee for storm tides. While this barrier dune is a

    major expense, it is often justified by the reduction in property damage

    due to such tides.

         For the purpose of this study, a minimal beach nourishment dimension

    is considered without a barrier dune (Fig. D-8).  The berm elevation is

    10 ft ( 3m) above MLW and has a width of 50 ft (15 m). The cost of

    beach nourishment depends primarily on the source of fill material.  Idea-

    ally, sand should be used which has been removed from the beach by the

    storm waves, i.e., immediately offshore or downdrift. Alternative

    sources include nearby inlets and landward areas.  Due to the absence of

    data for potential sources, a range of unit costs has been included which

    may be considered typical for a project of this magnitude; the fill

    volume was estimated to be 40 cu yd/ft ( 31 m3  /m).  The analysis that

    follows considers nourishment of the entire beach length (10 miles, 1km) anda

    - -r Lr - -~ mI -l -l mm -r 11                                                           m -

                    BERM
        4-        I-  DU 1
        �   10 1           l- FILL

                M.L.W    EXISTING
             0---        BEACH

              0        50         100        150       200       250        300       350        400

                                                DISTANCE (Ft.)-*

                            Fig. D-8.-Proposed Beach Nourishment - Myrtle Beac(-i

                                                                  214

    smaller project of 3.28 miles (5.2 km) directed at the most severely

    affected section of the beach.

    TABLE D-2

    Nourishment Cost
    Note:  Estimate includes engineering, supervision, etc.

              Unit Cost
                 (yd)                     Total Cost (in millions)

                                          10 mi. project       3.28 mi. project
                $5                              $10.5                 $3.4
                $6                             $12.7                 $4.2
               $7                              $14.8                 $4.9
                $8                             $16.9                 $5.5

    Offshore Breakwater

         In order to protect the project area from storm waves, large offshore

    breakwaters are considered.  These structures are built parallel to the

    shoreline at a depth which causes the storm waves to break before reach-

    ing the beach. Figure D-9 illustrates one possible design alternative

    for Myrtle Beach.  A series of structures are proposed, each 800 ft

    (244 m) long, with 1000 ft (305 m) spacings. The breakwaters would be

    in addition to the beach nourishment outlined in the previous section.

    These structures would reduce the frequency of beach renourishment by

    approximately half, as well as reduce the impact of individual large

    storms.

    TABLE D-3
    Breakwater Cost  (in millions of dollars)
    Note: Breakwater is constructed of large stone (12.7 tons/ft.) for the
           dimensions shown in Figure D-9.
        a.  stone for 32,440 ft of structure @ $45/ton        $18.6    $6.1
       b.  stone for 10,640 ft of structure @ $45/ton          1.9
        c.  engineering, supervision and contingency                      .6
                                                TOTAL       $20.5    $6.7

    I�                                                          215

                                          '    RUBBLE
                                         ,l a   BREAKWATER

           ~~~~~~I

                             D11A
                                        ' 1000'

                                   1500 oIjBO'

                               X190'
                                       I

                                      SECTION A-A

                        Fig. D-9 Proposed Breakwater and Position -
                                      Myrtle Beach

                                                                        216

                                      Benefit - Cost Analysis

     I            ~~~Myrtle Beach is the most significant commercial development along

    5        ~~the South Carolina coast.  Although the shoreline is relatively stable,

              long-term erosional trends at the southern end of the city and short-term

    j        ~~recession due largely to storm effects present a potential for serious

             property loss along the highly developed oceanfornt. In addition, a

    I        ~~continued loss of beach area may pose future constraints on the city's

    I        ~~important tourist industry.  The following section considers the economic

              feasibility of initiating alternate beach nourishment projects at Myrtle

    3        ~~Beact to alleviate damages inflicted by beach erosion.  The first alter-

             native considered is a 10 mile project for the entire city; the second

    I        ~~alternative is for the more severly affected area bounded by 13th Ave. N.

             and 29th Ave. S. The latter area includes the principle hotel district

             and has experienced erosion rates ranging from 0.8 to 2.0 m./yr.

    I        ~~Both projects consider beach nourishment and beach nourishment with off-

             shore breakwaters.

    3        ~~Prevention of Property Loss

                  Property values at Myrtle Beach are based upon the 1979 tax assess-

             ment for Horry County. Land and building values were collected for

    5        ~~oceanfront as well as second row properties located in areas subject to

              long-term erosional trends. Property values were then delineated to

    3        ~~account the partial loss over the planning period (Figure D-10).

             Observation of comparable oceanfront and second row properties at

             Myrtle Beach indicated that oceanfront properties include a 50 percent
    3        ~~premium reflecting the additional amenity associated with such location.

                                       Figure D-10    ZONES EMPLOYED FOR ASSESSING BEACH PROPERTY LOSS

                        Ye\~~~~~~~~~~~~~~~~~~~~~~~~~,

                   {                      I                      I                       I
                   I                      I                                                                                     I

                   I                      I                                  i                                                  i
     Fourth                 Third                 Second         J        First          I
    Quarter        I       Quarter               Quarter         J       Quarter         I                 Beach                       Tvoe of Loss
                              I          j                      I                      ~~~~~~~~~~~~~~~I                        I
                   [   0                  I        20%                    35%                               45%                        Amenity Loss

                   I                      j                                              at                                               Risk Loss
      5%                    25%                    40%           !        30%           10                                                  i
                   I                                             |                                                              ,         B          L
                                                                                                  I                           ~~~~~~~~~~~~~~~~i
                              I          I                     ~~~~~~~~~~~~~~~I                                                [
                                      2%  18%     50%           I         30%                               0                  j        ~~~~~~~~~~~~~~~~~Building Loss
                              I~~~~~~~~~~~~ I

                   �                                                       ~~~~~~~~~~~~~~~~~~~218

             For this reason, amenity and risk factors are separated. Amenity stems

    3        ~~from the existence of the beach; therefore, it is assumed that the

             majority of amenity value evolves from the beach and front lot (Figure

    I        ~~D-lO).  Amenity value is fully exhausted when the second quarter of the

             lot, is lost. The risk factor associated with the potential or actual

             loss of land occurs as open space between the water line and the build-

    3        ~~ing is eroded.  The risk factor is greatest in the first and second

             quarters as further erosion presents serious risk and uncertainty to

    I        ~~existing or potential buildings (Figure D-10).

                  Finally, building value is estimated based upon a sampling of build-

             ing patterns along the oceanfront. It was observed that on average

             buildings were situated on lots as indicated in Figure D-10; the majority

             of facilities are located in the first and second quarters of the lots

    1        ~~(29.4 and 50.3 percent, respectively).  This close proximity of struc-

             tures to the beachfront without sufficient open space to allow for shifts

             in the beach system significantly increases the potential for property
             damage in areas subject to short and long-term erosion.

                  Historical erosion rates based upon trends over the past 100 years

    3        ~~are superimposed on tax maps for the city.  By applying past trends to

             the present shoreline configuration, with an average beach width of 45

             meters at mean high tide, the potential for property loss' over the 50

    1        ~~year planning horizon is estimated.  It is assumed that the application

             of effective erosion control measures will prevent such a loss; therefore,

    5        ~~these figures represent the potential property benefit accuring from

             shoreline protection. Present values for these benefits are presented

    I        ~~in Table D-4 grouped by tax map designation and by section of the lot

                                                                         219

    TABLE D-4

    The Present Value of Property Benefit Accruing From Erosion Control at Myrtle
    Beach by Area and Lot Section.

    Alternative I (10 mile project)
                                     First         Second         Third        Fourth
    Tax Map-Section*      Beach       Quarter       Quarter        Quarter      Quarter

    174-04, 07, 08,
        09, 10, 11,
        13              $  240,774   $3,093,390   $12,094,938 $  834,069    $73,980

    181-04                  48,154       618,678        618,987    166,813       14,796

    181-07                 620,604              0              0          0           0

    181-10                 302,241    1,045,430       1,266,991    740,720       13,826

    181-11                 152,502              0              0          0           0

    181-13                  76,768              0              0          0           0

    181-14                 495,529    1,923,984       2,284,053    130,272       10,508

    186-08                 233,263       183,471        172,822      55,577       6,388

    187-01               1,676,094    1,203,653                0          0           0

    Sub-Total           $3,845,929   $8,068,606    $7,437,791 $1,927,451   $119,498

    TOTAL                                                                   $21,399,275

    Alternative II (3.28 mile project)

    181-07 (partial)      $366,307             0               0          0           0

    181-10                 302,241   $1,045,430    $1,266,991   $740,720    $13,826

    181-11                 152,502              0              0          0           0

    181-13                  76,768             0              0           0           0

    181-14                 495,529    1,923,984       2,284,053    130,272       10,508

    186-08 (partial)       193,608       152,280        143,442      46,128       5,302

    I  187-01            1,676,094    1,203,653               0           0           0

    Sub-Total           $3,363,049   $4,325,347    $3,694,486   $917,120    $29,636

    TOTAL                                                                   $12,229,638

    *Based on Horry County tax map designations.

                   5~~~~~~~~~~~~~~~~~~~~2

             eroded; estimates are made for both the 10 and 3.28 mile    proec

    5        ~~dimensions.  The total property benefit, in present value terms,

             resulting from effective erosion control measures is expected to be

    �        ~~$22.3 million in the first case and $12.2 million in the latter.  Yet,

             the shorter project offers significantly greater benefit on a per mile

             basis reflecting both the high value of properties and the relatively

    5        ~~rapid erosion occuring in this section of the beach.

             Recreation Benefit

     3            ~~~Peak visitation at Myrtle Beach is estimated to be 107,281 in 1980

              (LBC&W, 1979 with Dunes, 501 Corridor, and Southwest deleted). Accord-

    I        ~~ing to the same study, visitation is expected to increase by 26.9 percent

    5        ~~between 1980 and 1990 and to increase by 6.5 percent for the remainder

             of the century as the city seeks to limit further expansion. The present

    5        ~~study employs an 18 percent growth projection for the 1980 to 1990 period

             and a 10 percent increase per decade thereafter. Peak visitation projec-

    U        ~~tions averaged for each decade over the planning period are listed in the

    5        ~~same manner employed earlier for Pawleys Island (i.e., peak visitation

             2.5 x weekday visitation). (Table D-5, Items 1 and 2).

     3            ~~~Present carrying capacity of the sand beach is estimated to be

             111,746 visitors/day based upon an average width of 45 meters (MI-l) and

    I        ~~a beach length of 14.3 miles.  The space requirement is estimated to be

    3        ~~100 square feet per us'er with a turnover rate of one.  Based on these

             estimates, the beach is approaching capacity on peak days at the present

    5        ~~time, and     capacity will be reached for Sunday visits before the end

             of the projection period. Constrained visitation given the present

                                                                          221
    TABLE D-5a

    Projected Visitation and Recreational Value Accruing for Periodic Beach Nourishment
    at Myrtle Beach-Erosion Scenario I.

                              1980-90      1990-2000    2000-10        2010-20       2020-30

    1.  Visitation             4,957,168    5,582,515    6,246,038    6,870,656    7,557,786

    2. Daily Visitation
          Weekday (60)            47,665        54,598        60,058        66,064        72,671
          Sats (12)               71,498        81,897        90,087        99,096       109,007
          Suns (12)               83,414        95,547       105,102       115,612       127,174
          Peak (2)               119,162       136,495       150,145       165,160       181,677
    Alternative I:  10 Mile Project                           3

    3. Annual Visitation
         with project          4,935,426    5,607,970    6,007,118    6,240,426    6,457,186

    4.  Visitation
         without project       4,926,302    5,486,374    5,466,666    4,783,922    3,404,998

    s.   Differential               9,124      121,596       540,452    1,456,504    3,052,188

    6. Erosion
         Control Benefit         182,480    2,431,920   10,809,040   29,130,080   61,043,760

    7.  Present Value            149,999    1,349,716    4,053,390    7,369,910   10,438,483
        Sum of Present
    8.   Values                                                                      $36,284,513

    Alternative II: 3.28 Mile Project

    9. Annual Visitation
         with project          4,931,278    5,595,326    5,790,106    5,862,958    5,330,710

    10. Visitation
         without project       4,926,302    5,486,374    5,466,666    4,783,922    3,404,998

    11.  Differential               4,976       109,152       2323,440   1,079,036    1,925,712

    12. Erosion Control
         Benefit                  99,520    2,183,040    6,468,800. 21,580,720   38,514,240

    13.  Present Value             81,805    1,211,587    2,425,800    5,459,922    6,585,935

    14.  Sum of Present
         Values                                                                      $15,765,049

                                                                          222
    TABLE D-Sb

    Projected Visitation and Recreational Value Accuring for Periodic Beach Nourishment
    at Myrtle Beach-Erosion Scenario II.

                              1980-90      1990-2000    2000-10         2010-20       2020-30

    1.  Visitation            4,957,168    5,582,515    6,246,038    6,870,656    7,557,786

    2. Daily Visitation
          Weekday (60)           47,665        54,598        60,058        66,064         72,671
          Saturdays (12)         71,498        81,897        90,087        99,096       109,007
          Sundays (12)           83,414        95,547       105,102       115,612       127,174
          Peak (2)              119,162       136,495       130,145       165,160       181,677

    Alternative I:  10 Mile Project

    3. Annual Visitation
         with project         4,935,426    5,607,970    6.007,118    6,240,426    6,457,186

    4. Visitation without
         project              4,929,216    5,547,568    5,656,076    5,662,036    4,332,716

    5.  Differential               6,210        60,402       351,042       579,390    1,924,470

    6.  Erosion Control          124,200    1,208,040    7,020,840   11,587,800   38,489,400
          Benefit

    7.  Present Value            102,092       670,462    2,632,815    2,931,713    6,581,687

    8.  Sum of Present Value                                                        $19,500,456

    Alternative II:  3.28 Mile Project

    9.  Annual Visitation
         with project         4,926,402    5,598,898    5,863,166    5,965,242    5,765,698

    10. Annual Visitation
         without project      4,929,216    5,547,568    5,656,076    5,661,036    4,532,716

    11. Differential                3,186        51,330       207,090       304,206    1,233,522

    12. Erosion Control
          Benefit                 63,720    1,026,600    4,141,800    6,084,120   24,670,440

    13.  Present Value             52,378      569,763    1,553,175    1,539,282    4,218,645

    14. Sum of Present
          Values                                                                      $7,933,243

                    3                                                          ~~~~~~~~~~~~~~~~~~~~223

              beach formation is estimated to average 103,729 daily users in the first

    3        ~~decade and 39,593 in the final period a total loss of 69 percent of

              capacity over the project period. This erosion scenario assumes that

    I        ~~historical rates continue and that the shoreline is static with no

    3        ~~potential for beach migration.

                   Annual visitation under both project alternatives then is estimat-

    3        ~~ed and compared with the no action solution.  Under Alternative I,

              i.e., the 10 mile project, an annual differential of 3 million visitors

    I        ~~is projected resulting in $61 million of erosion control benefits &~r

    3        ~~the decade (benefits are calculated at $2/visitor x 10 years /decade).

              Under full beach nourishment, therefore, recreational benefits are

    3        ~~estimated to be $36.2 million in present value terms.

                   Alternative II in Table D-S depicts the same methodology applied

    I        ~~to a 3.28 mile project.  Because the area of beach fill is substantially

    1        ~~less than in the previous example, annual visitation with the project

              will also be less totaling an average of 5.3 rather than 6.4 million

             persons during the last decade. As a result, the projected erosion

              control benefit is also expected to be less amounting to $15.8 million

    I        ~~or 44 percent less than with the full nourishment approach.

     *            ~~~~A second erosion scenario is also employed with the findings de-

              picted in Table D-6. The second scenario assumes that, although erosion

    3        ~~rates continue, backward migration of the beach system will decrease net

              beach loss. Net beach loss is projected to be half of that occuring in

    5        ~~Scenario I.  As a result, although beach capacity will constrain peak

              and weekend activity, weekday visitation can be accommodated throughout

    I        ~~the period.  Annual visitation without the project will be larger

                                                                             224

    I        ~~reducing erosion control benefits than estimated particularly

    5        ~~during the latter years of the planning period.  Under Approach I,

              i.e., with nourishment of the full beach, the sum of present values

    3        ~~is expected to $19.5 million compared with the $36.2 million estimated

              under the first erosion scenario. With the 3.28 mile project the

    I        ~~present value of recreational benefits is estimated to be $7.9 million

    3        ~~or 50 percent lower than in the more rapid erosion scenario.

                   The difference between recreational benefits estimated under the

    3        ~~two scenarios is substantial.  Unfortunately, the state-of-the-art

              does not allow us to estimate with great precision the effect on beach

    I ~~capacity of erosional trends. Moreover, the introduction of physical

    3        ~~structures further complicates prediction.  What the figures do suggest

              is that, the degree to which the beach system is able to absorb and

    3        ~~adjust to erosional trends is most important.  Although physical barriers

              designed to prevent property loss may be effective in that regard, the

    I        ~~loss of beach capacity during critical erosion periods may be accelerated

              and may have serious consequences for tourist communities such as

              Myrtle Beach.

    3        ~~The Cost of Erosion Control Measures

                   It is anticipated that nourishment costs will range from $5 to $8

    I        ~~per yard under both of the proposed projects.  Initial project cost will

    3        ~~range from $10.5 to $16.9 million for the 10 mile project and from

              $3.4 to $5.5 million for the 3.28 mile project. Five-year renourishment

    5        ~~cycles are assumed with renourishment costs expected to be 60 percent

              of initial cost. Under these assumptions, the total cost of maintaining

    3        ~~the full 10 mile beach over the 50 year planning period is expected to

                                                                   225

    range from $67 to $108 million, while the present value of these

    expenditures is expected to range from $35 to $56 million (Table D-7,

    Section A and B). Costs for the 3.28 mile project are expected to

    range from $22 to $35 million, while the present value of these expen-

    ditures is expected to range from $11 to $18 million (Table D-7,

    Sections C and D).

         With the inclusion of an offshore breakwater to supplement nourish-

    ment, initial project costs are expected to rise by $20.4 million under

    the full nourishment alternative and $6.7 under the partial alternative.

    It is assumed that replacement will be required every 20 years. The

    renourishment cycle is extended from 5 to 10 years, however, as wave

    energy is dissipated along the shoreline.   (Table D-8).  Although the

    frequency of nourishment is decreased, total project costs for the 10

    mile project are expected to rise to a range of $86 to $109 million,

    and the present value of costs for the proposed nourishment project

    in combination with offshore breakwaters is predicted to range from $55

    to $69 million (Table D-8, Sections A and B).  With the proposed 3.28

    mile project, costs are expected to range from $29 to $36 million,

    and the present value of costs is expected to range from $17 to $21 with

    the combined nourishment/breakwater solution.

    Summary of Benefits and Costs

         Given the range of values for both project alternatives under

    alternate cost and depletion scenarios, the expected feasibility of beach

    nourishment at Myrtle Beach may vary significantly.  Table D-9 summarizes

    the present value of benefits and costs of the project under each of

    these scenarios.

    -    m W  -- -                                  mm  I                                                             -
             TABLE D-7
             Estimated Costs and Present Value of Costs for Proposed 10 and 3.28 Mile Beach Nourishment Projects.
             (in millions of dollars).

                           10 Mile Project                                     3.28 Mile Project

                             @ $5/Yard             @$8/Yard                   @$5/Yard                @$8/Yard
                               Pres. Value                Pres. Value              Pres. Value              Pres. Value
              Year    Cost      of Cost       Cost          of Cost      Cost       of Cost       Cost        of Cost

                0   $10,500     $10,500      $16,900      $16,900       $3,444    $3,444         $5,543    $5,543
                5     6,300       5,179       10,140        8,335        2,066     1,699          3,326      2,734
               10     6,300       4,259       10,140        6,855        2,066     1,397          3,326      2,248
               15     6,300        3,497      10,140        5,628        2,066     1,147          3,326      1,846

                         ,,   ,,                          ,,          , ,        ,    i  I, ,,                  i

               45     6,300        1,077      10,140        1734      ,2,066          353         5 543 5i543
             TOTAL  $67,200      $34,591    $108,160      $55,675      $22,038   $11,344        $35,477   $18,262

      TABLE D-8

      Estimated Costs and Present Value of Costs for Proposed 10 and 3.28 Mile Beach Nourishment Projects
      with Offshore Breakwaters (in millions of dollars).
                           10 Ilile Project                              3.28 Mile Project

                   @ $5/Yard               @ $8/Yard                 @ $5/Yard               @ $8/Yard
                      Pres. Value                 Pres. Value             Pres. Value              Pres. Value
    Year       Cost       of Cost      Cost         of Cost      Cost        of Cost       Cost        of Cost

      0      $30,927     $30,927      $37,327      $37,327      $10,143   $10,143         $12,242   $12,242

     10        6,300'      4,259       10,140        6,855        2,066      1,397          3,326     2,248

     20       26,727       12,188      30,567       13,939        8,765      3,997         10,025     4,571

     30        6,300       4,259       10,140        6,855        2,066        636          3,326     1,024

     40       166514        3,435      20,354        4,234        5,916      1,231          6,676     1,389

    TOTAL   $86,768      $55,068    $108,528      $69,210      $28,956   $17,404         $35,595   $21,474

              TABLE D-9
              Summary in Present Value Terms of the Benefits and Costs of Beach Nourishment at Myrtle Beach Under Alternate
              Project, Cost, and Erosion Scenarios (Figures in thousands of dollars)
    Alternative I (10 mile project)
                             Low Cost Scenario1                                       High Cost Scenario2
                      Rapid Beach Erosion3       Gradual Beach Erosion4        Rapid Beach Erosion       Gradual Beach Erosion4
                      Benefit         Cost       Benefit           Cost        Benefit         Cost      Benefit           Cost
    Property Value    $21,399                     $21,399                       $21,399                    $21,399
    Recreation Value   36,295                      19,500                        36,285                     19,500
    Project Cost                        $34,591                     $34,591                     $55,675                      $55,657
    Total              $57,684          $34,591   $40,899           $34,591    $57,684          $55,675   $40,899            $55,675

    Benefit/Cost Ratio                     1.67                        1.18                        1.04                         0.73

    Alternative II 3.28 mile project)
                             Low Cost Scenario                                      High Cost Scenario
                                                3  ~~~~~~4                                     .34
                     Rapid Beach Erosion3        Gradual Beach Erosion         Rapid Beach Erosion       Gradual Beach Erosion
                     Benefit           Cost      Benefit           Cost        Benefit         Cost       Benefit          Cost
    Property Value   $12,230                      $12,230                       $12,230                    $12,230
    Recreation Value  15,765                        7,933                        15,765                      7,933
    Project Cost                        $11,344                     $11,344                     $18,262                      $18,262
    Total             $27,995           $11,344   $20,163           $11,344    $27,995          $18,262   $20,163            $18,262

    Benefit/Cost Ratio                     2.47                        1.78                        1.53                         1.10

                      1Based on a nourishment cost of $5/yd and the construction of an offshore breakwater.
                       Based on a nourishment cost of $8/yd (no breakwater).
                      3Assumes a potential loss of 69 percent of beach capacity over the project period (S0 years).
                      4Assumes a potential loss of 37 percent of beach capacity over the project period.

                    3                                                          ~~~~~~~~~~~~~~~~~~~229

                   The use of offshore breakwaters is not considered in the analysis

    3        ~~as beach nourishment without breakwaters was deemed a more cost effective

              solution. Although both gradual and rapid erosion scenarios are used

    I        ~~to estimate recreational benefits, it seems more appropriate to estimate

    3         ~~benefits on the conservative side using the gradual erosion approach.

              Finally, the above analysis may represent an overestimate of erosion

    3         ~~control benefits as it is assumed that properties maintain values in their

              present form over the SO-year planning period. In other words, no pro-

    I         ~~vision for depreciation of the structure or for redevelopment of the

    3         ~~site to allow for erosional trends is made.

                   Alternative I, i.e. nourishment of the entire beach is estimated to

    3         ~~be feasible under the low cost ($5/yd) scenario; yet, as we might expect,

              the benefit/cost ratio is more favorable under the rapid erosion scenario.

    U         ~~(1.67 to 1.18)  With high nourishment costs, the project appears to be

    3         ~~marginally feasible only under the rapid erosion scenario.  We can con-

              clude then that nourishment of the entire beach may be feasible at a

    3         ~~~low nourishment cost, although the project may not be justified under

              high cost conditions.

     I             ~~~~For Alternative II, i.e. for the 3.28 mile project, the expected

    3         ~~returns are considerably more favorable.  Benefit/cost ratios range

               from 1.78 to 2.47 under the low cost scenario and from 1.10 to 1.53

    3         ~~under the high cost scenario.  These figures suggest that, based upon

               the assumptions made, beach nourishment in this portion of Myrtle Beach

    I         ~~may be justified using both conservative recreational benefits and a

    3         ~~~high cost construction scenario.  Should the city consider nourishment,

               therefore, it seems appropriate to focus first on the principal hotel

                    3                                                           ~~~~~~~~~~~~~~~~~~~~230

              district and on adjacent areas where erosion rates have been most severe.

    I        ~~The initial cost of such a project is estimated to range from $3.4 to

              $5.5 million with periodic replenishment required every 5 years. If

    I         ~~deemed appropriate, the city should consider the use of a local option

    3         ~~sales and/or accommodations tax (pending legislative approval).  Otherwise,

              user charges in combination with property tax increases, particularly in

    3         ~~the affected area, might be required to meet the city's bond obligations.

                   From a long-term perspective, however, and especially if beach

              nourishment is not pursued, the city should act to restrict construction
    3         ~~in erosion prone areas to alleviate losses in the future.  This policy

              would, by itself, reduce the potential property loss accruing from

    3         ~~erosion over the 50-year planning period considered.  Many of the present

              problems at Myrtle Beach stem from a failure to anticipate and incorporate

    I         ~~potential shifts in beach formation into development practices.  As the

    3         ~~city continues to develop and redevelop its oceanfront, new structures

              should be positioned in locations allowing for migration of the beach

    3         ~~over the expected lifetime of the structure.  It is recommended strongly

              that the city establish an effective setback law applicable to new structures.

    I         ~~Structural solutions to erosion problems should be permitted by both the

    3         ~~city and the State Coastal Council regardless of their location on public

              or private property, as if the structures is needed, it will have a direct

    3         ~~effect upon the public beach.  Permits for erosion control structures should

              be limited in time to the depreciation schedule remaining on the building~s)

    I         ~~requiring protection.  The city must decide if and under what circumstances

    3         ~~~it will permit erosion control structures for developments occurring

               after these new policies are enacted.

                                                                      231

                                   REFERENCES

    Armstrong, J. M., C. L. Kureth, Jr., W. C. Williams, D. V. Pratt, R. B.
       Denuyl, Community Erosion Protection System Analysis, The University
    of Michigan, Coastal Zone Laboratory, Technical Report No. 117, July (1979).

    Domeracki, D. and M. 0. Hayes, Assessment of Salt Marsh Sedimentation at
       Pawley's Island, S.C., Part I, Historical Survey, Research Planning
       Institute Report submitted to Pawley's Island Civic Association, Pawley's
       Island, S.C., (1980), 65 p.

    DuBar, J. R., "Pleistocene coquina at 204th Ave., South Myrtle Beach, South
       Carolina and other similar deposits," Southeastern Geology, V. 5, (1964),
       p. 79-100.

    Emery, K. 0., "A simple method of measuring beach profiles," Limnology and
       Oceanography, V. 6, (1961), p. 90-93.

    Fitzgerald, D. M., C. Fico, and Mo. 0. Hayes, "Effects of the Charleston
       Harbor, S.C. jetty construction on local accretion and erosion,"
       Proceedings, Coastal Structures 1979, American Society of Coastal
       Engineers, Alexandria, Virginia (1979), p. 641-664.

    Hanke, S. H., P. H. Carver, and P. Sugg, "Project Evaluation During Inflation,"
       Water Resources Research, Vol. II, No. 4, August  (1975).

    Hartzog, George B., Thomas W. Richards, and Philip Lader, Public Beach Access
       and Recreation in South Carolina, Report prepared for the S.C. Department
       of Parks, Recreation, and Tourism  (1974).

    Hayes, Miles 0., T. F. Moslow, and D. K. Hubbard, Beach Erosion in South
       Carolina, The University of South Carolina: Coastal Research Division,
       Geology Department (1977).

    Hubbard, D. K., Variations in Tidal Inlet Processes and Morphology in the
       Georgia Embayment, The University of South Carolina: Coastal Research
       Division, Geology Department, Technical Report 14-CRD (1977), 79 p.

    Nummedal, D. and S. M. Humphries, Hydraulics and dynamics of North Inlet,
       South Carolina: U.S. Army Corps of Engineers, (1977).

    Stepp, James M., J. B. London, and P. C. Luisa, The Projected Economic
       Impact of the Richard B. Russell Dam and Lake Upon South Carolina,
       Clemson University: Water Resources Research Institute, Report No. 60,
       February  (1976).

    U.S. Army Corpos of Engineers, Survey Report on Beach Erosion Control and
       Hurricane Protection, Charleston District Engineers, March (1974).

    U.S. Army Corps of Engineers, Hunting Island Beach, South Carolina Shore
       Protection Project, Project Evaluation, Charleston District Engineers,
    (1977).

           5                                ~~~~~~~~~~CHAPTER VIII

                                   CONCLUSIONS AND RECOMMENDATIONS

     3             ~~~~The costs associated with coastal erosion have become significant due

    3         ~~both to property loss and to the expense of preventative measures employed

              to minimize further loss. The primary cause of this problem stems from

    3         ~~the volatile nature of coastal processes and from building patterns that

              have proved incompatible with the natural system. Although the options

              available for controlling nature are limited, coastal development patterns
    3         ~~can and should be made consistent with coastal processes.

                   The state, as trustee of the public beaches and as protector of the

    3         ~~public interest, should provide a framework which allows for an optimal

              use of the state's resources from a long-term standpoint. In its re-

              source management capacity, the primary functions of the state should be:
     '3                 ~~~~~1) to provide for access and maintenance of the public beach,

                         2) to develop and disseminate information allowing individuals

       3                   ~~~~~~and communities to make well-informed decisions concerning

                            utilization of the resource, and

      3                 ~~~~~3) to institute mechanisms serving to minimize or correct for

       3                   ~~~~~~the external effects of individual actions that adversely

                            affect other individuals or the community as a whole.

    3         ~~Within this framework, individual property owners and local communities

              should be allowed maximum possible discretion in decisions which are

    I         ~~consistent with state policy.  At the same time, it clearly is not the

    3         ~~responsibility of the state to subsidize risk-taking by individual

              property owners where appropriate information is provided and individual

    *         ~~~discretion is allowed.

                                                                              233

                   The recommendations that follow are prefaced by the realization that

    3         ~~state policy will continue to be influenced significantly by federal

              policy with respect to the coastal zone and specifically to erosion

    I         ~~control policy.  The current reevaluation of federal policy may have

              considerable impact on state programs; yet, it seems essential that

              coastal states clearly define appropriate policies in this regard without

    3         ~~further delay.  The South Carolina Coastal Management Plan and present

              state enabling legislation provide an institutional basis for doing so.

    I         ~~~It is recommended, therefore., that the following items be addressed and

              that the accompanying provisions be given serious consideration to supple-

              ment present state policy.

         *                           ~~~~~~~~Long-Run State Policy

                   Recognizing its coastal beaches as among its most valuable resources,

    I         ~~the state must commit itself to the management of these resources to

              provide the greatest possible benefits to its residents. Such an approach

              must include a long-run perspective recognizing the volatile nature of
    3         ~~~the coastal system and encouraging building patterns which are compatible

              rather than at odds with natural processes. The guidelines implemented

    3         ~~~should be clear and consistent relying on ad hoc decisions for short-

              term emergency situations rather than as a fundamental long-run approach.

    I         ~~~Specific attention should be given to the following components in develop-

    3         ~~~ing such a strategy:

              Data Collection

     5             ~~~~There is a basic need for additional data for both planning and

              engineering design purposes. A program of permanent wave data collection

    U         ~~~is needed at a minimum of three points along the coast.  These stations

                    5                                                          ~~~~~~~~~~~~~~~~~~~234

              should be part of the Federal Wave Data Program of the National Ocean

    5        ~~Survey.  Information on wave height, period, and direction is necessary

              in both the analysis of coastal processes and in the design and evalua-

    *        ~~tion of erosion control alternatives.

                   In addition to wave data., a program should be initiated to monitor

              and catalogue erosion and accretion at fixed stations along the entire

    3        ~~coast.  These profile stations should be established with permanent

              benchmarks using precise surveying techniques. New surveys should be

    1        ~~made at least semi-annually, as well as after significant storm periods.

              This information is essential to accurately assess and accommodate short-

              term and long-term shoreline erosion or accretion.

    5        ~~Public Awareness

                   Public awareness of the dynamics of the coastal system should be en-

    3        ~~couraged through public forums sponsored by the South Carolina Coastal

             Council and South Carolina Marine Advisory Program. Similarly, information

              and pertinent state and local policy as well as historical erosion trends
              should be distributed to prospective buyers of property in hazard areas

             through the office of the county building inspector. Properties in

    3        ~~hazard areas should be so designated as such with the disclaimer that

              individuals are building at their own risk.

    I        ~~Technical Assistance

     *            ~~~~It will be necessary for appropriate state agencies and scientists

              developing coastal process information to work closely with local officials

    5        ~~to provide input as well as regulatory and planning support.  Technical

              assistance and financial support to establish and maintain local programs

    3        ~~should be provided by the state through its coastal management program.

                    g                                                          ~~~~~~~~~~~~~~~~~~~~235

              Building Standards

     5             ~~~~The construction of both buildings and erosion control structures

              should be governed by uniform construction codes. Although individual

    U         ~~property owners must be encouraged to incorporate risk in their decision-

    5         ~~making, the potential for property transfer and high rate of nonowner

              occupancy suggest that minimum standards should be established to assure

    3         ~~reasonable levels of safety.  This code should be based upon the unique

              set of conditions peculiar to areas which experience the direct inter-

    1         ~~action with storm waves and surge as well as wind and erosion damage.

              Such a code should be applied on a state-wide basis, although local

    U         ~~enforcement may be both necessary and desirable.

    3         ~~~Setback Lines

                   Realizing that its coastal beaches are subject to dynamic conditions

    3         ~~and, in some cases., to long-term erosional trends, the state should en-

    U         ~~courage and give standing to the establishment of a coastal setback line

              demarcating potential hazard areas to prospective development. By re-

    3         ~~stricting development in hazard areas, setback provisions will lessen

              the potential for conflict between private property owners and public

    *         ~~and adjacent private properties emerging from critically eroding conditions.

              Building setbacks offer a consistent, institutional mechanism superior to

              ad hoc solutions development patterns and problems that may ensue. In
    3        ~~extreme cases where a setback line may entail a significant taking of

              property rights, compensation may be required.

     *            ~~~~A comprehensive setback law should:

                        1) incorporate site specific scientific data to the extent

       I                   ~~~~~~practical to anticipate and accommodate serious erosion hazards,

                                                                               236

      1                ~~~~~2) provide a minimum buffer zone (generally drawn from the

                           mean high water line and/or the crest of the primary dune)

                           from which development would be prohibited,

      1                 ~~~~~3) designate particularly volatile areas such as inlets or

                           locations experiencing particularly acute erosional patterns,

                        4) include provisions for dune protection,
                        S) allow for local ordinances to reinforce or, in some cases,

                           provide for more restrictive controls as deemed appropriate

       3                   ~~~~~~to the local community and,

      1                 ~~~~~6) accommodate periodic revision of the guidelines as physical

                            conditions change as more scientific data is provided.

    *         ~~Specific figures are not presented at this time as they should be determined

              pending state approval of the concept and a determination of the extent

    *         ~~to which site specific scientific data or standard distances are to be

              used. Setback laws in Florida and New Jersey are typical of the state-

    1         ~~~of-the-art.

         3                           ~~~~~~~~Short-Run State Policy

                    Past development in coastal areas has been poorly planned in some

    3         ~~cases and present plans are made without certainty.  For these reasons,

              the potential loss of property will continue to be of concern and short-

    U         ~~term measures will be required.  The following recommendations are made

    3         ~~~concerning such decisions:

               Permitting Authority

     3             ~~~~The principle tool for addressing short-term erosion control problems

              must continue to be state permitting authority. Guidelines for structural

    I         ~~~and nonstructural approaches have previously been documented (SCCMP IV

                                                                              237

              (4) (c)) and new recommendations are being considered at the present

             time. Requests for permission to construct erosion control structures

              should be accompanied by:

      I                ~~~~~1) an assessment of the potential impace on adjacent lands

       *                   ~~~~~~and the public beach,

                        2) a consideration of alternate erosion abatement techniques

                           including where applicable management options, and

                        3) a reasonable justification indicating that the project

       I                  ~~~~~~may be considered in the best interest of the public.

                   In general, structures should not be permitted for periods to

              exceed the remaining depreciation period on the building to be protected.

              In addition, new structures built in the future should be subject to

              stringent guidelines and prove that unusual circumstances prevailed

    I        ~~before permits for erosion control structures are issued.  Permitting

              authority should apply to all erosion control structures impacting the

              public beach presently or in the foreseeable future. It can be argued

    *        ~~that erosion control structures are unnecessary if they do not potentially

              affect the beach system.

     I            ~~~~Broader permitting authority should also be extended to consider

              the impact of additional development activity on the systems natural

              and physical carrying capacities. Complementary authority should be

              considered by localities as a means of augmented state responsibility

              and assuring that local considerations are met as well.

    *        ~~Relocation

                   Under some circumstances, it may be more cost effective to relocate

              structures than to protect them from emnminent property loss. The same

                    1                                                          ~~~~~~~~~~~~~~~~~~~~238

              funding formula in terms of state and federal share applied for engineer-

              ing solutions should be applied for relocation. Compensation, if paid,

              should be based upon the depreciated value of the structure and fair

    I        ~~market value for the land.

          3                            ~~~~~~~~~Local Participation

                   Local discretion should be incorporated in management of erosion

              control problems to the maximum extent practical as local jurisdictions

              can achieve maximum responsiveness to local conditions, better account-

    I        ~~ability, and greater public accessibility.  To provide a basis for activet

    3         ~~local participation, appropriate jurisdictions should be encouraged to

              develop local coastal erosion programs. Components of the program should

    3         ~~~include:

                         1) an identification and evaluation of coastal resources

       I                   ~~~~~~that require management and protection by localities

       3                   ~~~~~~as specified in the Coastal Zone Management Act and the

                            South Carolina Coastal Management Plan,

      3                ~~~~~2) an examination of existing and proposed statutes pro-

                            viding a basis for managing coastal resources,

      I                ~~~~~3) a delineation of areas within the coastal zone and an

                            identification of appropriate uses for these areas, and

                         4) a description of legal authorities and organizational

       3                   ~~~~~~arrangements needed to implement the program.

                   Specific components of local programs should include:

      1                ~~~~~1) a description of long-term policy relating to develop-

       *                   ~~~~~~ment and to erosion control measures,

                         2) a provision for and set of guidelines establishing and

                    3                                                          ~~~~~~~~~~~~~~~~~~~239

                           providing enforcement for coastal land-use controls -

                           the provisions should include a local setback line, a

                           provision for dune management,

      I                ~~~~~3) a determination of appropriate short-run policies to deal

       3                  ~~~~~with emergency situations - local permitting authority

                           should be considered, and as suggested previously, tech-

       3                  ~~~~~nical assistance and financial support to establish and

                           maintain local erosion control programs should be provided

       I                  ~~~~~~by the state through its coastal management program,

      3                ~~~~~4) an identification of funding measures designed to meet

                           the required local share for erosion control measures.

           *                              ~~~~~~~~~Funding Policy

                   State funding for erosion control should be based upon policies

    I        ~~outlined in SCCMP IV C (4) (a).  Priorities and funding formulas should

    *        ~~be established for projects based upon the following ranking:

                         1) state owned public beachfront,

      3                ~~~~~2) municipality owned public beachfront,

                        3) quasi-public beachfront where public access is provided,

      I                ~~~~~4) privately owned recreational beachfront where public

       3                   ~~~~~~access is provided, and

                        5) privately owned recreational beachfront.

    3        ~~Project costs should be borne primarily by the beneficiaries of the

              project. State monies should be made available only to commjnities

    3        ~~that have, in force, or in the immediate future to communities develop-

              ing for approval, a local erosion control program indicating that the

              jurisdiction is taking a responsible approach to minimize the impact

                    1                                                          ~~~~~~~~~~~~~~~~~~~240
              of erosion damage.

                   it is expected that further bond issues will be required to meet

              the state share of erosion control projects. The allocation of such

    I        ~~funds should be distributed based upon the criteria and formulas sugges-

    3        ~~ted previously.  In addition, the project must be justified as being

              in the public interest and as being the most cost effective solution to

    I        ~~the problem.  To meet local obligations, the adoption of a local option
              sales tax and/or an accommodations tax offer the potential for tourist

    I        ~~communities to support beach maintenance.  Communities should also con-

    3        ~~sider user fees administered at public parking areas and local property

              taxes as local conditions warrant as possible revenue sources.

    I

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                          �923.25  S.%oreliie    eroson/nitigatian    (vi) probable Impacts of re-establishment
                                       planning.    ~~~~~of Pre-erosion shoreline or rebuilding an
                                       planning.                     ~~~~~wetiwnds and natural habitat, particularly
                          (a)   Statutory   Citation,   Section   as the re-establishment or rebuilding migzht
                         305(b)(9):.               "I'  relate to the Executive Orders on Wetlands
                          The management program for each coast-  and Ploodplaiis (see 5 923,Z;(b)(2,(ij)).]
                        al state shall include 11*    A planning proc-    (2) There must be an identification
                        ess for (A) assessing the effects of shoreline  and description of enforceable policies,
                         erosion (however caused). and (B) studying  legal authqrittes. funding techniques
                         and evaluating ways to control, or lessen the  and other techniques that will be used
                         Impact of, such erosion. and to restore areas  to manage the effects of erosion as the
                                    ~rsey afecte bysucheroson.State's planning prccess Indicates is
    I                   ~     ~~~~~~(b) The basic purpose In developing  necessar.
                        this planning process is to give special    tCominen,L  In developing a Prom=s  to
                         attention to erosion IssueS. ThI'S Siae-  manage the effects of erosion, States should
                         cial  management  attention  may  be  consider.
                         achieved by designating erosion areaes   (1) the extent and location of erosion prob-
                         as areas of particular concern pursu-  lems;
                         ant to � 923.21 or as areas for preserv-    00I the necessity for control versus non-
                         tion   or   restoration   pursuant   to   control of erosion'.
                         5923.22.                                       (iii) whether structural (e.g.. groins) or
    I                      (~~~~~~~c) Requirements. (1  The  manage-  nonstructural controls (e.g.. land use &et-
                                    anent pogram  ust Inlude amethod baci.s) are appropriate;
                         fetpor     -a austesinclude effectsoshorein    (lv costs of alternative solutions (includ.
                                    for  ssesing he efect   of  horeine ing operation and maintenance costs); and
                         erosion and evaluating techniques for    (v) the National Flood Insurance Program
                         mitigating,  controlling  or  restoring  (24 CFR 1909 et seg.) and regulations of the
                        areas adversely affected by erosion.          Federal Insurance Administration on flood.
                                                                     related erosion-prone reas (24 CFR 910.83).
                           [Comm-e"& In developing assesM-3nent and    (COvment. Due to restrictions on the use
                         evaluation techniques. states should consid-  of section 306 Iu~nds (see 9 923.94). not all
                          er'I)lsofidaonthshrle                      j means of restoration proposed by Stztes
                                     (1)los  o !Lndalan  th  sorein oree I may be eligible for funding under section
                         tuarifle ba-tcz                              306 or other sections of the Act. According-
                           (iii wneuler the lowe resulted from natural  ly. particular attention should be given to
                         or mazi induced forces;                      coordination of shoze.Lne erosion imaxage-
                           (Iii) whether the erosion is regularly 00  merit objectives with funding progroms Dur-
                         curring, cyclical, or a one time event :     suant to the U.S. Army Corps of Engineers
                           (tv) Imports off the erosion on adjacent  Beach Erosion Control Program (33 U.S.C.

                            1ecshorelines. land and -ater I,= Uitta  %L=smybepropit.)
                         r-., dr,!L andoter natural processessuha
    I                  ~     ~~~~~~accretion, and
                                       FEDERAL R!GISTIR, VOL 4, No0. 61-WEDHESOAY, MARCH 23, 1979

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      EROSION CONTROL POLICIES
       The Coastal Council will apply the following policies in its review and evaluation of permits for the
    following erosion control activities:

    Seawalls, Bulkheads and Revetments (Riprap)
    1) Seawalls, bulkheads and revetments will be considered only as part of a comprehensive erosion control
    program to insure that these structures do not cause adverse effects to adjoining property owners or ap-
    preciably accelerate erosion in the general beach area.

    2) These structures must not interfere with existing or planned public access unless other adequate access
    can be provided.

    3) These structures shall not impede public use of beaches below the mean high water line (R.30-13(2)(C).

    4) These structures should be sloped seaward or concave with riprap at their bases to reduce the adverse
    effects of scouring where appropriate.

    5) Applications for construction of a seawall in the beach or dune critical areas for the purpose of filling
    behind these structures to create land for private development shall be denied unless the applicant can
    clearly demonstrate to the Council that no feasible alternatives exist, that the individual circumstances are
    extenuating such that they demand an exception to the general policy and that the project would other-
    wise be consistent with the coastal management program.

    6) Except under special circumstances, such as critically eroding shorelines that have a direct measurable
    effect on the economic well-being of an applicant or are a threat to the public safety, the Council will pro-
    mote the use of natural features of the dune and beach system rather than artificial protection
    (R.30-13(2)(a)).

    7) Additionally, all other regulations covering bulkheads and seawalls will be applied in the critical areas
    (R.30-12(C)).

    8) Riprap must consist of appropriate materials.

    Groins
    1) Significant volumes of sand via the littoral transport system should be available.

    2) The extent to which the downdrift beach areas will be damaged must be determined before construc-
    tion.

    3) The adequacy of shore anchorage of groins to prevent "flanking" as a result of erosion must be
    demonstrated.

    4) The positive effect and applicability of a groin system in a comprehensive shore protection program
    must be demonstrated.

    5) Care must be taken to insure that groins do not interfere with public access (R.30-13,C(2)(c).

                                                                                          245

    Offshore Breakers and Jettko
    1) Since these structures tend to impound littoral drift on their updrift sides, provisions should be made
    so that sand is pumped at appropriate intervals to downdrift areas so as not to starve these areas of sand
    thereby creating or worsening an erosion problem.
    2) Care must toe taken to insure that jetties do not interfere with public access (R.-30-13, C(2)(C)).

    3) Where appropriate, jetties should be designed to provide recreational fishing opportunities
    (R.30-13,C(2)(d)).

    4) Construction activities should be scheduled so as not to interfere with nesting and brood-rearing ac-
    tivities of important seabird colonies or other wildlife species (R.-30-13,C(2)(3).

    5) These structures should be consistent with other erosion measures being undertaken as part of any
    comprehensive shoreline protection projects.

    Artificial Beach Nourishment
       1) A thorough study of littoral transport mechanics as well as beach slope, grain size, and berm
    geometry should be done before artificial nourishment is attempted.

       2) Sand for artificial nourishment should come from offshore deposits or areas of active accretion and
    from bars or spits only where it can be clearly demonstrated that no negative impacts will result in
    downshore areas. Fill material should not come from dune fields, adjoining beaches or nearshore bars.

       3) Dredging in the borrow areas should not be in conflict with spawning seasons or migratory
    movements of significant estuarine-marine species.

       4) Dredging offshore shall be done in locations and in such a manner so as not to create anoxic sumps
    or uncover toxic or anoxic deposits.

       5) All other policies concerning dredging and filling (R.30-12,G) will be applied to beach nourishment
    proposals.

       6) Careful study must be given to the type (size, quality, etc.) of fill material most suitable for use in a
    particular beach area.

       7) Nourishment of beach areas should be scheduled so as not to interfere with nesting or brood-
    rearing activities of important seabird colonies or other wildlife species.

       8) The recreational and public access requirement of the affected beach area will be a major concern
    when determining the width of the beach fill.

       9) Where possible, inlet stabilization and/or navigation projects shall be done in concert with artificial
    nourishment projects.

       10) Structural control measures should be used, where appropriate and feasible, to complement ar-
    tificial nourishment projects.

                                                                                       246

    Sand Dune Management
       1) Private and public projects to restore and stabilize dunes through non-structural means are en-
    couraged.
       2) To the extent possible, the secondary dunes should be kept intact to insure protection of adjoining
    areas against flooding during storms.

       3) Buffer areas should be established, where feasible, to allow for frontal dune growth and mrnve-
    ment.

       4) All plans for dune restoration, reconstruction or stabilization should be part of a comprehensive
    shoreline protection program.

       I . 5) Dune reconstruction should be done only above the existing berm line or in line with existing fron-
    tal dunes. Dunes should be constructed using only native material (sand) of the appropriate grain size and
    stabilized with native vegetation. Consultation is encouraged with Soil Conservation Service advisory ser-
    vices in determination of plant materials most suitable for dune stabilization.

       6) Walkover structures are encouraged over all frontal dunes (R.30-13, B.) However, these walkover
    structures should not interfere with public access or extend below the mean high water line.

       7) Seawalls, bulkheads or revetments should not be placed in front of frontal dunes, except where
    severe erosion is indicated and unless there are no feasible alternatives or there is an overriding public in-
    terest.

       8) Public access should be provided either over frontal dunes via walkover structures or by using
    natural breaks through frontal dunes. In no case shall access be provided by bulldozing or cutting open-
    ings through frontal dunes.

       9) In all cases, the primary front-row sand dune, as defined in R.30-10(B), should not be permanently
    altered.

    U.S. Department of Commerce, Office of Coastal Zone Management, "State of South
    Carolina Coastal Management Program and Final Environmental Impact Statement",
    Section IV 4(c), 1979.