1.2 Sea wolf Mound 



Dredging of the Thames River was deemed necessary when the U.S. Navy decided to 

 homeport the Seawolf class submarines in Groton, CT (Maguire Group 1995). The Seawolf 

 dredging project and a small-scale Mystic River project resulted in the placement of 

 306,000 m^ of UDM, which was subsequently covered by 556,000 m^ of CDM in the 1995- 

 1996 season (SAIC 2001b). An additional 15,500 m^ of sediments from Venetian Harbor 

 and Mystic River deemed suitable for open-water disposal was placed at the NDA 95 buoy to 

 the southwest of the main Seawolf Mound. This smaller project also contributed to the 

 Seawolf Mound and was documented in the depth difference calculations between sequential 

 bathymetric survey grids. The Seawolf Mound was last surveyed with REMOTS® and 

 bathymetry in July of 1998. 



13 USCGA Mound 



The USCGA Mound was developed during the 1994-95 disposal season as part of a 

 confined aquatic disposal (CAD) project. A total of 124,000 m^ of dredged material was 

 placed approximately 1 80 m west of the historic NL-TR mound apex. The USCGA Mound 

 consisted of 43,500 m^ of UDM subsequently covered by 80,500 m^ of CDM. The pre- 

 existing NL-TR and NL-II mounds to the east, and the NL-RELIC Mound to the west, served 

 to restrict the lateral spread of the dredged material composing the USCGA Mound. The 

 USCGA Mound was last surveyed with sediment-profile photography and bathymetry in 

 August of 1995 (SAIC 2001a). Based on the findings of the initial environmental monitoring 

 survey (benthic recolonization exceeding expectations), follow-on assessments were deferred 

 until August 2000 to monitor the long-term recovery of the surface sediments. 



1.4 Objectives and Predictions 



Field operations at NLDS in August 2000 included precision bathymetry and 

 sediment profile photography surveys. Individual bathymetric survey grids were established 

 over the NL-91 and D/S Mound Complex and the Seawolf Mound project areas. Sediment- 

 profile photography surveys were performed over the NL-91 and D/S Mound Complex, the 

 Seawolf Mound, and the USCGA Mound, as well as the NLDS reference areas. These 

 surveys repeated those conducted during previous monitoring cruises to allow detection of 

 possible changes over time. 



The objectives of the August 2000 monitoring surveys were to: 



• Map the extent of supplemental CDM placed over the NL-9 1 and D/S Mound 



Complex project area since September 1997; 



Monitoring Cruise at the New London Disposal Site, August 2000 



