38 



shallower than measured at the I and H mounds (Table 3-3). Boundary roughness was 

 attributed primarily to physical effects. 



3.4.2 Benthic Community Assessment 



Successional stages were split between Stage I and III organisms. The RPD depths 

 ranged from 0.8 cm to 6.33 cm. The overall median OSI value was 7 for both areas. For 

 SOUTH, the median OSI values ranged from 3 to 9, and for SW-REF, 3 to 8 (Table 3-3). 

 The low OSI values at some stations may have been due to low dissolved oxygen 

 conditions in September (Section 4.1.2). 



3.5 New Reference Area Investigation 



Previous monitoring surveys have detected historic dredged material at several 

 previous and proposed reference areas surrounding WLIS (EAST, WLIS-REF, 2000S, and 

 3000E) which were then discontinued. The most recent 1996 REMOTS® survey detected 

 dark, reduced sediments and methane gas bubbles in three replicates from 2000W 

 reference area indicating the presence of weathered dredged material (Morris 1998). This 

 finding was not surprising considering that the reference area was located within the 

 Stamford Historic Disposal Site. To replace 2000W, we conducted a series of surveys to 

 locate an area with a 300 m radius clear of historic dredged material. 



3.5.1 Side-Scan Sonar 



For the first time, a side-scan sonar survey was used to locate and investigate a 

 potential reference area. The survey in September, however, was limited to a small area 

 by the many lobster pots dispersed throughout the area that obstructed survey operations. 

 We postponed the reference area investigation to the winter, when lobster gear would be 

 less intense in the region. 



Although some lobster gear continued to pose hazards in March, the side-scan sonar 

 survey was still conducted near WLIS. The initial side-scan sonar survey was designed 

 over a 2000 x 4000 m area east-southeast of WLIS to locate a region representative of 

 natural ambient conditions. The presence of abundant lobster gear and dredged material on 

 the seafloor prompted on-site revisions. 



The orientation of the initial 2000 x 4000 m survey area was altered to due east- 

 west with the northwest comer of the survey located within WLIS and was reduced in size 

 to 1500 X 4000 m (Figure 2-3). A second smaller survey was designed to examine an area 

 north of Eaton's Neck and west of a rocky reef in an area where lobster gear was minimal. 



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



