34 



3.2.2.2 Benthic Community Assessment 



The replicate-averaged mean RPD values were fairly high, ranging from 1.33 cm at 

 200S to 3.59 cm at 200E (Figure 3-14). No conditions indicative of low DO or methane 

 gas generation were observed in any replicate over the G mound. 



A successional stage recolonization status of Stage II moving to Stage III is expected 

 over a one-year-old dredged material disposal mound (Germano et al. 1994) The benthic 

 infaunal population over the G mound is mainly comprised of Stage I individuals with 

 some indications of Stage III activity in photographs collected at stations on the G mound 

 periphery (Figures 3-15 and 3-16A and B). Moderate recolonization and deep RPD depths 

 have resulted in OSI values that range from 3.0 at 200S to 10.5 at 200E (Figure 3-14). 



3.3 WLIS F Mound 



3.3.1 Bathymetry 



The F mound is a moderate-sized bottom feature that was developed 100 m north of 

 the terminal moraine margin over a three-year period (Figure 3-17). The initial deposit 

 formed during the 1991-92 disposal season was composed of 38,700 m^ of dredged 

 material. The small sediment mound was detected by the July 1992 bathymetric survey as 

 a 1.9 m high, 200 m wide bottom feature (Figure 3-18). 



An additional 41,600 m^ of material was placed over the F mound during the next 

 two disposal seasons (1992-93 and 1993-94). The continued disposal over the F mound 

 resulted in a 2.0 m increase in mound height and a broadening of the apron surrounding 

 WLIS F (Figure 3-19). Comparisons with the July 1990 master survey over WLIS display 

 a total mound height of 3.0 m and an approximate width of 275 m (Figure 3-20). 



3.3.2 REMOTS® Sediment-Profile Photography 



A comprehensive REMOTS® sediment-profile photography survey was not 

 performed over the F mound. However, the eastern arm of the 13-station cross 

 REMOTS® grid over the G mound extended over the F mound. Station G200E profiled 

 the center of the F mound, while Stations GIOOE and G300E collected data 100 m west 

 and east of the center, respectively. 



Overall, the F mound appears healthy with replicate-averaged RPD depths ranging 

 from 2. 15 cm at G300E to 3.59 cm at G200E (Figure 3-14). The OSI value of 10.5 at 

 G200E is a result of the deep RPD and the observation of Stage III organisms in two of the 



Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1996 



