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6.9 BUZZARDS BAY DISPOSAL SITE 



6.9.1 Summary of BBDS 



The Buzzards Bay Disposal Site (BBDS) is located approximately 1.4 nmi from 

 Chappaquoit Point, West Falmouth, Massachusetts. The site consists of a 500 yard 

 (457.25 m) diameter circle centered at 41°36.000' N, 70°41.000' W, lying within a slight 

 depression between the 9 m and 12 m isobaths (Figure 6-60). Side-scan sonar and 

 REMOTS® sediment-profile surveys, conducted in 1981 to characterize the general area, 

 revealed six major textural regions: a deposit of coarse-grained material, a small wave-like 

 field possibly consisting of large sand waves overlying silt-clay sediments, a cratered bottom, 

 a rubble bottom, an eastern flat bottom, and a western flat bottom. The eastern and western 

 flat bottoms have been interpreted to represent natural ambient bottom unaffected by disposal 

 operations. The mound tip, a circular region approximately 500 m in diameter south of the 

 1990 survey area, apparently reflects the center of prior disposal operations (Germano et al. 

 1989). An 800 x 800 m area centered at 41°36.000' N and 70°41.000' W was surveyed in 

 March 1990 (Figure 6-61). 



Tidal currents are the dominant circulation forces in Buzzards Bay; the area is 

 protected from large, long -period waves by the presence of the Elizabeth Islands to the 

 south. Overall, BBDS lies in a portion of the bay that exhibits relatively low kinetic energy, 

 where the tidal currents average 20 cm-s" 1 (SAIC 1989c). Complete tidal mixing of bay 

 water with ocean water is estimated to occur approximately every 10 days. Water 

 temperatures in the bay range from a summer maximum of 22° C to 0° C in winter. 

 Salinity levels are essentially the same as those of Block Island and Vineyard Sounds, 

 ranging from 29.5 to 32.5 ppt, due to a minimal amount of freshwater inflow (primarily 

 groundwater seepage) (SAIC 1989c). 



In the late 1800s, the Massachusetts Division of Marine Fisheries prohibited finfishing 

 in Buzzards Bay by seine, trap, or trawl in an effort to protect the area as a nursery for 

 commercial fish species. This ban is still in effect, and only hook and line fishing is allowed 

 in the bay. 



Monitoring activities at BBDS have been limited in the past six years due to limited 

 disposal activity. Since 1981, the only monitoring that took place was the field survey 

 conducted in March 1990 to provide information on the effects of past disposal operations. 

 That survey cruise included a bathymetric survey, REMOTS® sediment-profile photography, 

 and sediment sampling for benthic, chemical, and physical analyses. 



BBDS has received a wide range of dredged material types, although intermittently 

 over a number of years. The most recent disposal projects began in February 1979. The 

 sources of the material have been small harbor and river projects throughout the Buzzards 



DAMOS Summary Report, 1985-1990 



