43_ 



REMOTS® results for the WLIS D mound are available in Appendix D. The results of the 

 1996 survey showed significant variability between the three replicates at each station. In 

 general. Station 300S showed strong improvement with a median OSI of 8.0 and RPD 

 depth of 2.74 cm (Figure 3-21; Appendix A, Table 3-3). Stage III individuals were 

 detected in the subsurface sediments in two of three replicates, and biogenic activity was 

 responsible for surface roughness. 



One replicate at Station D200S showed excellent benthic conditions with the 

 presence of Stage III activity, an RPD depth of 3.61 cm, and an OSI value of 10. 

 However, the two remaining replicates displayed indications of low DO, Stage I 

 individuals only, and negative OSI values (Figure 3-22). As a result, the replicate- 

 averaged values, and the overall impression of benthic community health were degraded 

 for Station 200S. 



The variability between replicates within a 25 m watch circle suggests that the poor 

 benthic conditions are part of a localized problem between the stations 200 m and 300 m 

 south of the D mound center. Further evidence of this isolation are the favorable 

 conditions detected at Station GIOOW, approximately 25 m north-northeast of D200S 

 (Figure 3-23). Depth difference plots indicated the apron of the newly developed G mound 

 may have spread over D200S and D300S. However, the accumulation was not sufficient 

 to establish a healthy benthic environment in some areas. 



3.5 WLIS Reference Areas 



As part of the DAMOS tiered monitoring protocols, reference area data are 

 collected to provide a baseline against which results from the dredged material mounds are 

 compared. A total of thirteen stations were occupied over three reference areas (2000W, 

 SOUTH, and SW-REF). Reference area 2000W has been used for comparisons with 

 WLIS sediments since the November 1987 monitoring cruise; SOUTH and SW-REF are 

 recent additions to the DAMOS Program (SAIC 1990). Complete REMOTS® results for 

 the WLIS reference areas are available in Appendix E. 



3.5.1 Sediment Grain Size and Stratigraphy 



In the past, several reference areas (EAST, WLIS-REF, and 2000S) in the vicinity 

 of WLIS have been abandoned due to detection of the presence of dredged material 

 resulting from earlier deposition at the surrounding historic disposal sites. Unfortunately, 

 the latest REMOTS® data set collected over the 2000W reference area, which is positioned 

 inside the northwestern boundary of the historic Stamford Disposal Site, has detected the 

 presence of dark, reduced sediments and methane gas bubbles indicating the presence of 



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



