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6.2 WESTERN LONG ISLAND SOUND DISPOSAL SITE 



6.2.1 Summary of WLIS 



The Western Long Island Sound Disposal Site (WLIS) is located 2.7 nmi south of 

 Long Neck Point, southeast of Stamford, Connecticut, between the Stamford and Eaton's 

 Neck historical disposal grounds (Figure 6-10). The site is 1 nmi 2 , centered at 40°59.400' N 

 and 73°28.700' W. Water depth at the center of the site is approximately 33 m, with an 

 overall range from 24 to 34 m. The sediments consist primarily of fine silts and clays with 

 some patches of relic dredged material from the discontinued Eaton's Neck disposal site 

 (SAIC 1988a). 



Scientists from SAIC conducted the baseline survey at WLIS in January 1982 (SAIC 

 1982). This survey indicated that diurnal tidal changes within Long Island Sound were the 

 principal influence governing the current regime, reaching 20 and 18 cm-s" 1 for flood and 

 ebb tides, respectively. The limited fetch within the region reduces the incidence of storm- 

 driven, wave-induced currents and, in conjunction with the east-west trending trough in the 

 southwest region of the site, provides conditions ideal for the containment of dredged 

 sediments. Since disposal first began at WLIS in March 1982, varying quantities of dredged 

 material have been deposited annually. As a result, four distinct dredged material disposal 

 mounds ("A", "B", "C, and "D") currently exist at the site (Figure 6-11). 



Lobstering is the most important fishery at WLIS. Prime lobster fishing grounds are 

 located east and west of the site at the previously used disposal sites, as well as in the 

 vicinity of Cable and Anchor Reef. In addition, leased oyster beds are present north of 

 WLIS in the shallow waters off Norwalk and Stamford, Connecticut. Disposal is curtailed 

 from June through August when oyster spawning activity is high (SAIC 1988a). 



SAIC conducted six monitoring surveys at WLIS since fall 1984. They occurred 

 annually and/or followed the cessation of major disposal events (SAIC 1987a, 1988b, 1990d, 

 1990e, Germano et al. 1993). The objectives of the surveys included determining the areal 

 extent of dredged materials and the stability of the disposal mounds, evaluating the response 

 and subsequent recolonization of the benthic environment, and monitoring chemical and 

 physical sediment parameters and water column DO content. Assessment techniques 

 included precision bathymetry, side-scan sonar, sediment sampling for physical, biological 

 and chemical analyses, SCUBA diver observations, current meter and transmissometer 

 deployments, invertebrate bioaccumulation, CTD/DO monitoring, and REMOTS® sediment- 

 profile photography (SAIC 19900- 



Approximately 633,000 m 3 of dredged sediments were deposited at WLIS (Figure 6- 

 12). The dredged material either was added to pre-existing disposal mounds or formed new 

 mounds. The steepness of the disposal mounds at WLIS supported the premise that the 



DAM OS Summary Report, 1985-1990 



