In September 1995, the NDA 95 buoy was deployed at 41° 16.402' N, 72° 04.905' W 

 (41° 16.396' N, 72° 04.934' W, NAD 27), approximately 245 m southwest of the central 

 disposal point for the Seawolf Mound. DAMOS disposal logs indicated a total estimated barge 

 volume of 10,590 m 3 of sediments determined to be suitable for unconfined open-water 

 disposal was deposited at the NDA 95 buoy; this material was df edged from Venetian Harbor 

 and Mystic River in southeastern Connecticut and disposed at the site between 25 November 

 1995 through 1 1 March 1996 (Figure 1-3 and Appendix A). The resulting dredged material 

 deposit overlapped the Seawolf Mound. After postcapping surveys conducted in February 1996 

 (see below), a small volume of CDM sediment (4,900 m 3 ) from Mystic River was placed near 

 NDA 95 through 1 1 March 1996. 



Pre-dredging characterization of the Seawolf Project sediments detected elevated 

 levels of polycyclic aromatic hydrocarbons (PAHs) and trace metals (Cu, Cr, and Zn) in a 

 small area adjacent to the proposed submarine berthing areas (Maguire Group 1995). These 

 contaminants were found in low (Class I) to moderate (Class II) concentrations (NERBC 

 1980) and were attributed to storage and maintenance of vessels in the area (Maguire Group 

 1995). A fraction of these Seawolf Project sediments with elevated contaminant levels were 

 classified as UDM based on biological testing. In addition, a small volume of the Mystic 

 River sediments from Mystic Seaport was also classified as UDM. The unacceptably 

 contaminated sediments from these projects required a comprehensive disposal site 

 monitoring program to insure adequate coverage of CDM to isolate the UDM from the 

 marine environment. The monitoring program included baseline, precapping, and 

 postcapping surveys to ensure the proper placement of UDM and adequate coverage with 

 CDM (Figure 1-3). 



Several bathymetric surveys were sponsored by the U.S. Navy during the 1995-1996 

 disposal season to track post-depositional changes in the Seawolf Disposal Mound (Table 1- 

 1 ). A summary of these earlier monitoring efforts conducted under contract to the Navy by 

 Gahagan and Bryant, Inc. of Baltimore, MD is included in the Results section of this report. 

 SAIC conducted surveys at the Seawolf Mound in 1997 and 1998 through the DAMOS 

 Program to meet technical and management objectives of the U.S. Navy monitoring plan 

 (Maguire Group 1995). Bathymetric surveys were conducted to document the changes in 

 bottom topography due to dredged material disposal (Table 1-1). Sediment profile imaging 

 was used to assess the benthic recolonization status of the Seawolf Mound relative to three 

 reference areas surrounding NLDS. Sediment grab samples were collected to examine the 

 benthic infaunal species diversity and relative abundance over the surface of the Seawolf 

 Mound. Finally, cores were collected at the mound to assess the physical and chemical 

 composition of the deposited sediments and to determine the thickness of the cap material 

 layer. 



Monitoring Cruise at the New London Disposal Site, Seawolf Mound 1995 - 1998 



