Recent disposal activity has been located to take advantage of the bottom topography 

 created by historical disposal mounds. Two management objectives have been sought: 

 creation of a "bowl" by placement of mounds in a "ring"; and constraint on the spread of 

 dredged material disposed at the site. The lateral spread of dredged material disposed 

 through the water column is strongly affected by bottom slope (Bokuniewicz et al. 1978). 

 By placement of the taut-wire moored disposal buoys, disposal activity can be directed to 

 specific locations and thereby limit the horizontal spread of material by filling depressions or 

 confining material between adjacent, older mounds. Minimizing lateral spreading of 

 mounds can increase site capacity and reduce the volume of material required for capping. 

 Additionally, in order to reduce the potential effects of bottom currents and storm-generated 

 waves, sediment mounds at the NLDS are developed in a broad, flat manner, maintaining a 

 minimum water depth of 14 meters. This minimum depth also allows for the safe passage of 

 deep draft vessels transiting through the disposal site (NUSC 1979). Presently, there are 10 

 discernible mounds (NL-95 is merged with the Seawolf Mound) within the boundaries of the 

 disposal site (Figure 1-2). 



The Thames River, located in southeastern Connecticut, discharges fresh water and 

 sediment from the interior of eastern Connecticut into Long Island Sound. The mile-wide 

 basin of the lower Thames River and New London Harbor is utilized by military, 

 commercial, and recreational vessels seeking protection from the open waters of Long Island 

 Sound (Figure 1-1). Maintenance dredging of New London Harbor and adjacent coastal 

 areas, overseen by the NAE, is required to insure navigable waterways and adequate 

 dockage for deep draft vessels. Most of the material generated from dredging operations is 

 transported by barge and deposited at the New London Disposal Site (NLDS) in Long Island 

 Sound. 



Disposal of dredged material occurred within and around the NLDS area for a number 

 of years before the inception of the DAMOS Program. The formation of the NL-RELIC 

 Mound was a result of dredging and disposal of sediments from the Thames River and New 

 London Harbor prior to 1977 and during the early 1980s (NUSC 1979; SAIC et al. 1985). The 

 area surrounding the NLDS is subject to moderate to high bottom currents (maximum bottom 

 current of 55 cms' 1 ) relative to other containment disposal sites in Long Island Sound (Waddell 

 et al. 2001). However, the shelter provided by Fisher's Island, the southern fork of Long Island 

 and the Connecticut shoreline, protect the disposal site from the effects of major storm waves. 

 This inference is supported by the fact that historic disposal mounds have remained stable in 

 both height and shape over at least ten years, and in some cases (such as NL-RELIC) twenty 

 years or more (Figure 1-2). 



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



