Woods Hole Group performed a comprehensive evaluation of regional sediment transport processes along Horseneck Beach, Gooseberry Neck, East Horseneck Beach, and Little Beach in the Towns of Westport and Dartmouth, Massachusetts.  Sediment transport patterns and alternatives for beach stabilization were evaluated along with various management and engineering alternatives for the causeway connecting Gooseberry Neck to the mainland.  The initial study effort described the historical evolution of the coastal system, and included an analysis of shoreline change using historical photographs and maps.  The dominant coastal processes (waves, tides, currents, winds, storms, etc.) and their impacts on the evolution of this complex littoral system were identified.

Once the nature of the system was better understood, a more detailed evaluation of the beach was completed using a combination of field data collection and numerical modeling.  Field data included beach and inlet sediment grain size and beach profile data from sixteen transects monitored during the Spring 1995, Spring 1996, and Summer 1996.  An additional survey following Hurricane Edouard provided a quantitative measure of profile storm response.  The numerical model, REFDIF, was used to transform deep-water wave conditions to the shoreline, taking into account wave refraction and diffraction.  The wave modeling was required to estimate the driving forces governing the sediment transport during both storm-related and average annual conditions.

Once the wave heights and directions for storm and average wave conditions were determined, the longshore sediment transport model, GENESIS, was employed to estimate the net annual longshore sediment transport.  The cross-shore model, SBEACH, was used to determine the profile changes as a result of storm waves and their related surge.  A combination of the results from the field data collection and numerical model analyses provided a quantitative analysis of the sediment budget for the site.  The GENESIS model also was used to complete an alternatives analysis on five proposed engineering and/or management options for the Gooseberry Island causeway.  Potential solutions to stabilize the existing beaches were evaluated as well.  Results from this study indicated that maintenance of the existing causeway and nourishment of East Horseneck Beach were the most feasible alternatives.