1.0 INTRODUCTION 



The New London Disposal Site covers a one square nautical mile area and is centered 

 at latitude 41° 16. 100' N and longitude 72°04.600' W. It is located approximately three 

 nautical miles south of Eastern Point, Groton, CT (Figure 1-1). This site has been 

 monitored by the Disposal Area Monitoring System (DAMOS) Program since 1977. Several 

 disposal mounds currently exist at New London as a result of past and recent disposal 

 operations. 



Field operations were conducted from 28 June to 9 July 1990. Sampling tasks 

 included precision bathymetric and REMOTS® sediment-profile photographic surveys around 

 the points where the disposal buoy was located during the 1989-90 disposal season (Figure 

 1-2). Previous surveys of the entire disposal site occurred in July 1986, July 1987, and July 

 and August 1988. To understand the specific questions addressed in the present survey, it is 

 helpful to examine the chronology of disposal operations at the New London Disposal Site 

 during the past two years. 



Following the 1988 master survey, a temporary buoy was placed in the northeast 

 quadrant of the site at 41°16.425' N, 72°04.320' W for deposition of sediment generated by 

 dredging activities at the Thames Shipyard and Repair Company Project (Table 1-1). These 

 sediments were classified as unsuitable for unconfined open water disposal. The mound 

 formed as a result of this project is referred to as NL-TR (Figure 1-2). On 17 October 

 1988, an 800 X 800 m postdisposal survey encompassing the NL-TR region was conducted 

 to determine the distribution of dredged material (SAIC 1988). Subsequently, capping 

 material was deposited at six locations (Table 1-2) surrounding NL-TR to cover the dredged 

 material from the Thames Shipyard and Repair Company (SAIC 1988). Capping operations 

 took place from 23 October 1988 to 23 January 1989, and resulted in the deposition of an 

 estimated 59,500 m 3 of dredged material, based on barge logs. The report from the 

 postcapping bathymetric survey of February 1989 recommended that additional material be 

 deposited at locations "A", "B", "C", and "F" (Table 1-1) due to inadequate cap thickness 

 (SAIC 1990a). Disposal at NL-TR resumed on 13 March 1990, and continued through 

 17 June 1990 (Buoy 90; Table 1-1, Figure 1-2). Barge logs indicate that 39,483 m 3 of 

 dredged material was released during that time. 



Since the 1988 master survey, dredged material has also been disposed at Buoy 88 

 (41° 16. 100' N, 72°04.350' W) approximately 700 m south of the NL-TR region and 150 m 

 west of the NL-85 mound (Table 1-1, Figure 1-2). From 25 January to 10 March 1989, and 

 from 30 October 1989 to 16 February 1990, approximately 21,200 m 3 of dredged material 

 was deposited at this location. 



Monitoring Cruise at the New London Disposal Site, June-July 1990 



