BUZZARDS BAY DISPOSAL SITE 



BASELINE STUDY 



MARCH 19 9 



1.0 INTRODUCTION 



The Buzzards Bay Disposal Site (BBDS) is located in the 

 northern half of the bay, 1.4 nautical miles from Chappaquiot 

 Point, West Falmouth, MA. The site is a 500 yard diameter circle 

 centered at 41° 36.000'N and 70° 41.000'W, lying within a slight 

 depression between the 9m (30 ft) and 12m (40 ft) isobaths. 

 Disposal records indicate that, since 1979, 92,000 cubic meters of 

 dredged material have been deposited at the site. From February 

 1979 to January 1984, an average of 17,200 m 3 of material was 

 deposited annually from small harbor and river channels throughout 

 the Buzzards Bay region. The last substantial use of the site was 

 in the fall of 1985, when the Massachusetts Maritime Academy 

 disposed of 55,000 m 3 of material. Several projects recently have 

 received permits to use the site, and 600 m 3 were disposed from a 

 small project in the fall of 1989. Sediments disposed at BBDS have 

 been relatively uncontaminated sands and sands containing some silt 

 and clay (Table 1-1) . 



Monitoring activities at the site have not been conducted 

 by the DAMOS program over the past several years, because the site 

 has been used infrequently. The largest collection of site- 

 specific data was gathered in 1981 by Germano et al. (1989) , and 

 regional data have been summarized in an earlier report (SAIC, 

 1989a) . 



A side-scan sonar and REMOTS® sediment-profile survey of 

 the region was conducted in 1981 to characterize the historic 

 disposal site with an area of 2 . 8 km 2 . Five major textural regions 

 were revealed: 1.) a deposit of coarse-grained material, 2.) a 

 small wave field possibly consisting of large sand waves overlying 

 silt-clay sediments, 3.) a cratered bottom, 4.) a rubble bottom, 

 and 5.) two areas of flat bottom on the east and west sides of the 

 disposal mound (Figure 1-1) . The eastern and western flat bottoms 

 have been interpreted to represent natural ambient bottom 

 unaffected by disposal operations. In 1981, the disposal mound 

 apex rose to within seven meters of the sea surface and apparently 

 was the center of prior disposal operations. The disposal site 

 surveyed in March 1990 was smaller (0.8 km 2 ) in area than the 1981 

 site and encompassed the wave field and portions of the rubble 



