FUNCTIONING OF GROINS AT WESTHAMPTON BEACH, LONG ISLAND, NEW YORK

Abstract

An extended field of 15 long rubble stone groins was constructed in two increments of work at Westhampton Beach, New York, in 1965-66 (11 groins) and in 1969-70 (4 groins), as part of a hurricane storm-protection project. A third increment of work completing the protection to a downdrift point of closure was not undertaken due to political decisions. In addition, the dune and beach fill which was to have been placed in the first 10 groin compartments to complete the protection was not accomplished due to local economic problems. No construction work has been undertaken since 1970. During the 26 years following completion of the original 11 groins, substantial portions of the groin field have been filled naturally by trapping of sediment that moves alongshore with a net rate directed to the west. However, the shore area downdrift of the last westerly groin in the unconstructed increment of work has experienced inordinate recession because of insufficient bypassing of sediment to this area. This paper describes the functioning of the groin field, examining both the extreme downdrift recession and the equally dramatic accretion and beach build up in the groin field, drawing lessons on groin functional design from this historic project.