2J_ 



4.0 DISCUSSION 



Despite the large amount of material (approximately 4.2 million m 3 ) disposed at the 

 historical Bridgeport Disposal Site prior to 1977, side-scan sonar used during the 1992 survey 

 revealed no dredged material mounds. Rather, numerous low-relief, high-reflectance 

 features, inferred to be dredged material, were present throughout the disposal area. The 

 most plausible cause for the wide distribution of dredged material was the fact that, over a 

 twenty-five-year disposal period, a target disposal buoy was never deployed. 



The habitat quality of infaunal benthos within the disposal site was, in general, stable. 

 The average OSI for all stations was +7, and the presence of Stage IE deposit-feeding 

 assemblages indicated the benthic environment was relatively healthy. Among the 13 stations 

 analyzed using REMOTS®, however, OSI values were not consistently high, nor were Stage 

 IE fauna present at every station. The OSI values at Stations B22, B23, B29, and B30 were 

 less than +6 due to the presence of Stage I fauna only and the relatively low RPD depths 

 (Figure 4-1). Two of these stations (B22 and B23) were stations where no dredged material 

 was present (Figure 3-6), indicating no correlation between the presence of dredged material 

 and OSI. In the remaining stations, the OSI values were high, ranging from +7 to +11, 

 because Stage HI organisms were present. High OSI values occurred even though the RPDs 

 for these stations were relatively shallow. Although REMOTS® data indicated a healthy 

 benthic community overall, recolonization was somewhat patchy in the area surveyed. The 

 patchy distribution of Stage DH assemblages may be caused by bottom trawling activities that 

 -disrupt the sequence of infaunal recolonization, or by long-term impact from contaminated 

 dredged material. Both the scattered pattern of trawl marks and dredged material deposits 

 are evident in the side-scan record at Bridgeport (Figure 2-2). 



Reconnaissance Survey of the Historical Bridgeport Disposal Site, August 1992 



