BEACH CHANGES AT WESTHAMPTON BEACH, NEW YORK, 1962-73. 



by 

 Allan E. DeWall 



I. INTRODUCTION 



Beach changes observed during repeated surveys at Westhampton Beach, 

 New York, conducted by the Corps of Engineers from 1962 to 1973, are 

 analyzed as part of the U.S. Army, Coastal Engineering Research Center 

 (CERC) Beach Evaluation Program (BEP) (formerly known as the Pilot Program 

 for Improving Coastal Storm Warnings or Storm Warning Program). The BEP's 

 objective is to measure beach and dune changes due to erosion and accre- 

 tion at selected localities and relate these changes to the coastal pro- 

 cesses producing them. The BEP was a direct outcome of investigations 

 into the effects of the Great East Coast Storm of March 1962 (see U.S. 

 Congress, 1962). Twelve beaches in the region hardest hit by that storm 

 (Massachusetts to North Carolina) are presently under study in this pro- 

 gram. The surveying at Westhampton Beach is coordinated by CERC; the 

 U.S. Army Engineer District, New York, is responsible for the fieldwork. 



This report presents an analysis of beach profile changes at West- 

 hampton Beach, documents the precise location of the surveyed profile 

 lines, and describes the survey procedures used and accuracy obtained 

 in repetitive surveys to wading depth. 



Profile changes are analyzed in three parts: (a) short-term changes, 

 including storm- induced changes and other changes between surveys; (b) 

 long-term changes, including seasonal and yearly changes; and (c) some 

 effects of a groin field and beach fill constructed during the study 

 period. The variables analyzed include the mean sea level (MSL) shore- 

 line position and the volume of sand stored on the beach above the MSL 

 datum. Apparent trends in beach changes are correlated with observed 

 wave conditions. 



Volumetric change data to -6 meters MSL obtained before, during, and 

 after groin construction are also presented (U.S. Army Engineer District, 

 New York, 1976). 



Metric units are used throughout this report except for specifications 

 in data collection and computer processing where U.S. Customary units are 

 given with the metric equivalent. 



II. STUDY AREA 



Westhampton Beach is a barrier island located on the south shore of 

 Long Island, approximately 120 kilometers northeast of New York City 

 (Fig. 1). The barrier island is 22 kilometers long, and ranges from 

 ISO to 800 meters wide. The island is bounded on the east by Shinnecock 

 Inlet and on the west by Moriches Inlet, and is separated from the Long 

 Island "mainland" by the shallow Shinnecock and Moriches Bays and by 



