1.0 INTRODUCTION 



The Cornfield Shoals Disposal Site (CSDS) is located 3.3 nmi south of Cornfield 

 Point in Old Saybrook, Connecticut (Figure 1-1). It is the only dredged material disposal 

 site managed as a dispersive site by the US Army Corps of Engineers, New England 

 Division (NED), as part of the Disposal Area Monitoring System (DAMOS) Program. At a 

 dispersive disposal site, unlike a containment site, it is expected that dredged material 

 disposed at the site will be transported out of the area. 



The Cornfield Shoals Disposal Site has been under study by the NED as part of the 

 DAMOS Program since 1978. From 1978 to 1991, the site received low volumes of mostly 

 hydraulically dredged sands (29,000 m 3 annually) although some mechanically dredged fine- 

 grained material (5,500 yds 3 from North Cove) was released at the site in January 1988. 

 The material was released at LORAN-C coordinates, usually at the center of the disposal 

 site. Bathymetric surveys conducted before 1991 did not detect any well-defined dredged 

 material disposal mounds (SAIC 1988, Germano et al. 1994). 



As part of a joint study between the University of Connecticut and the Newport, RI, 

 office of Science Applications International Corporation (SAIC), a taut-wire moor?«' buoy 

 was deployed at two locations within CSDS in 1991. Between 12 September and 9 October 

 1991, 50,803 m 3 of sandy dredged material was released at buoy location A2 (Figure 1-2). 

 Between November 13, 1991 and April 14, 1992, 105,479 m 3 of fine-grained dredged 

 material from North Cove was released at buoy location B. Coincident with these disposal 

 operations, a near-bottom current meter was deployed at BTM-A (near A2) on August 8, 

 prior to disposal, and moved to BTM-B (near B) on October 21. A midwater current meter 

 (MWM) was deployed southwest of BTM-A on August 1 (Figure 1-2). A series of studies at 

 CSDS from July 1991 (predisposal) to May 1992 (postdisposal) documented the accumulation 

 of dredged material at these buoy locations and provided circumstantial evidence for active 

 bed transport in the area (Wiley 1994). The current meter data showed the east-west tidal 

 component as the dominant current direction. Maximum velocities for the midwater meter 

 were 120 cms" 1 on the spring tide and 60 cms" 1 on the neap. For the nearbottom meter, 

 maximum velocities were 80 cms" 1 on the spring and 40 cms 1 on the neap. All of these 

 current velocities are sufficient to erode medium to fine sands (Bohlen et al. 1992) 



The accumulation of dredged material at CSDS from 1991 to 1992 was detected both 

 with bathymetry and with REMOTS® sediment-profile photography. The bathymetric 

 surveys from August 1991 to May 1992 documented the formation of the disposal mounds 

 and illustrated the shifts in sediment accumulation patterns over time. These shifts in 

 accumulation patterns may have been due to the addition of dredged material to the site 

 and/or to the natural sediment transport patterns within the area. 



Monitoring Cruise at the Cornfield Shoals Disposal Site, August 1992 



