13_ 



center. The REMOTS® survey over the H mound grid, centered at 40°59.228' N, 

 73°28.732' W (NAD 27), was sampled every 50 m in accordance with the 1996 survey. 

 The I mound was centered at 40°59.203' N, 73°29.072' W (NAD 27), with station 

 spacing at 50 m. In March 1998, the central five stations were reoccupied for comparison 

 with the September results. In addition, a 25-station radial grid, with three replicate 

 photographs at each station, was conducted over the new reference area, SE-REF, 

 identified in the side-scan sonar survey (Figure 2-5, Appendix A Table 2). 



Data from the existing reference areas SOUTH and SW-REF were used for 

 comparison of ambient western Long Island Sound sediments relative to the sediments 

 deposited at WLIS through disposal operations. Reference area SOUTH (40°58.688' N, 

 73°29.201' W) was sampled at six randomly selected stations and SW-REF (40°58.688' 

 N, 73°29.909' W) was sampled at seven stations. 



2.6 Side-Scan Sonar 



In an effort to locate potential reference areas to replace 2000W REF, a side-scan 

 sonar survey was attempted over a 2000 x 4000 m area to the east-southeast of WLIS (in 

 September 1997). However, clusters of lobster fishing gear located within the region 

 impeded progress of the survey. As a result, the side-scan sonar survey operations were 

 postponed until late November and then until March. 



In March, the planned side-scan sonar survey over a 2000 x 4000 m area east- 

 southeast of the WLIS disposal site was revised due to the presence of abundant lobster 

 gear and dredged material identified on the seafloor. The orientation of the initial survey 

 area was altered to a 1500 x 4000 m area oriented east- west with the northwest comer of 

 the survey located within WLIS (Figure 2-5). A second smaller survey was designed to 

 examine an area south of Eaton's Neck and west of a rocky reef in an area where lobster 

 gear was minimal. This smaller survey consisted of 10 survey lanes measuring 1000 m in 

 length and spaced 100 m apart. Side-scan images of the seafloor within the small 1000 x 

 1000 m survey identified areas with no apparent dredged material. However, these areas 

 were in relatively shallow water, less than 18 m, that may not be representative of the 

 ecological conditions at WLIS which has depths varying between 30-35 meters. Side-scan 

 operations were continued in the modified 1500 x 4000 m survey area in water depths 

 greater than 18 meters. A potential reference area, SE-REF, was identified at 

 40°58.301 'N, 73°27.722'W, NAD 27, with a mean water depth of 19.5 m. 



Side-scan sonar data were collected with an EdgeTech DFIOOO towfish. Acoustic 

 signals at a frequency of 100 kHz were emitted from two transducers mounted in the DFIOOO 



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



