1.0 INTRODUCTION 



The Western Long Island Sound Disposal Site (WLIS) is about 2.7 nmi north of 

 Lloyd Point, New York, and 2.5 mni south of Long Neck Point, Connecticut, located 

 along the east-to-west axial depression that extends through Long Island Sound (Figure 

 1-1). Three historic disposal grounds, Stamford, South Norwalk, and Eaton's Neck, 

 surround the active site. To regulate and carefully manage disposal operations in western 

 Long Island Sound, the New England District of the U.S. Army Corps of Engineers 

 (NAE) chose WLIS as the western Sound's only active site in 1982, under the auspices of 

 the Disposal Area Monitoring System (DAMOS) Program (USACE 1982). The 

 established 5.29 km^ disposal site has accepted small to moderate volumes of dredged 

 material originating from Stamford, Norwalk, and other coastal communities of 

 Connecticut and New York. 



The long-term management strategy for disposal of dredged material at WLIS is to 

 form potential containment basins for future use as confined aquatic disposal cells. Some 

 sediments from industrialized harbors have elevated contaminant levels that are best 

 isolated from the marine environment. The containment basins are designed to minimize 

 the lateral spread of fine-grained dredged material during and after disposal and to 

 maximize the overall capacities for containing polluted dredged sediments. Due to the 

 success of capping and containing large volumes of dredged material (over one million 

 cubic meters) at the Central Long Island Sound Disposal Site, potential containment basins 

 continue to be developed at other DAMOS disposal sites in preparation for managing 

 contaminated sediments in the fumre (Morris et al. 1996). At WLIS, the disposal mounds 

 have been placed in rings to build containment berms in relation to the naturally steep 

 upward slope of the seafloor to the south of the disposal site. 



WLIS is set in a fine-grained depositional environment, characterized by relatively 

 weak tidal currents (Knebel et al. 1998). Because many tributaries flow into western Long 

 Island Sound, fine-grained particles are continually added to the estuarine waters and 

 gradually settle out onto the seafloor. To determine the impact of disposed dredged material 

 at the site, reference areas near WLIS are monitored to examine the ambient sediments and 

 monitor benthic conditions for comparison. Before the DAMOS Program was established, 

 disposal operations were not subject to a developed management plan, resulting in an 

 extensive distribution of historic dredged material throughout western Long Island Sound. 

 Since 1991, historic dredged material has been detected at several former WLIS reference 

 areas that therefore were discontinued (3000E, EAST, WLIS-REF, 2000S, and 2000W; 

 Eller and Williams 1996, Charles and Tufts 1996, Morris 1998; Figure 1-2). 



Monitoring Cruise at the WLIS Disposal Site, September 1997 and March 1998 



