41 



major mode ranging from +6 to +8 (Figure 3-21). Several stations with median OSI values 

 > +7 were located within 100 m of the center of the WLIS "F" mound. 



Based on the results of past REMOTS® surveys, OSI values of < +6 are considered 

 indicative of benthic habitats which have experienced recent disturbance (i.e., erosion, 

 dredged material disposal, hypoxia, etc.; Rhoads and Germano 1986). The areal distribution 

 of the 1992 OSI data showed that stations with OSI values < +6 were located primarily at 

 the active disposal point or along the west and south axes of the WLIS "F" grid (Figure 3- 

 22). The lowest median OSI values ( + 1.5 and +2) occurred at stations F200VV and 

 F200NE, respectively. 



Median OSI values for reference areas 2000W, SOUTH, and EAST were +5, +4, 

 and +6, respectively. The bimodal frequency distribution of the median OSI values for the 

 39 pooled reference stations show two distinct major modes at +4 and +8 (Figure 3-23). 

 The areal distribution of median OSI values showed the patchy, heterogeneous habitat 

 conditions within each reference area. Median OSI values for the 1991 reference areas 

 (2000W, 2000S, and WLIS-REF) were +9, +4, and +7, respectively. 



3.3 Selection of Alternate Reference Areas 



3.3.1 Preliminary REMOTS® Survey at SOUTH and EAST 



The results of the reconnaissance REMOTS® photographs and preliminary sediment 

 sampling excluded several of the proposed reference areas from further consideration as 

 replacements for WLIS-REF and 2000S. Shell lag and buried oxygenated layers indicated 

 that these areas may have been affected by past disposal activities. Triplicate reconnaissance 

 photographs taken from the proposed SOUTH and EAST reference sites (coordinates 

 40°58.700' N, 73°29.200' W and 41°00.200' N, 73°27.150' W, respectively) revealed 

 relatively homogeneous sediment profiles (Figure 3-24). Photographs from the center of the 

 proposed EAST reference area showed mud clasts on the sediment surface. Because EAST 

 was located approximately 3000 m northeast of the WLIS "F" mound, these mud clasts were 

 not considered to represent recently deposited material. Triplicate REMOTS® photographs, 

 taken along a 13-station cross-shaped grid, further characterized the habitat conditions within 

 EAST and SOUTH. REMOTS® parameters measured for these stations are presented in 

 sections 3.2.2 through 3.2.6. 



3.3.2 Bathymetric Characterization 



Two-laned, cross-shaped bathymetric surveys were run to delineate the general 

 topographical characteristics at the SOUTH and EAST reference areas (Figure 3-25). The 

 west-east bathymetric survey lane at reference area SOUTH showed that water depth 

 increased from 25 m (400 m west of center) to 27 m (at the center), and then decreased to 



Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992 



