1.0 INTRODUCTION 



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 the Adantic 

 Ocean and Long Island Sound. Maintenance dredging of New London Harbor and adjacent 

 coastal areas, overseen by the U.S. Army Corps of Engineers, New England District (NAE), 

 is required to insure navigable waterways and adequate dockage for deep draft vessels. Most 

 of the material generated from dredging operations in the New London region is transported 

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



The New London Disposal Site (NLDS) is an active open water dredged material 

 disposal site located 5.3 km south of Eastem Point in Groton, CT (Figure 1-1). Centered at 

 41°16.306' N, 72° 04.571 ' W (NAD 83), the 3.42 km^ NLDS has water depths which range 

 from 14 m over the NL-RELIC Mound to 24 m at the southern disposal site boundary. Two 

 important management boundaries bisect the NLDS: a 300 m submarine transit corridor and 

 the New York-Connecticut state boundary (Figure 1-1). The submarine corridor was 

 established to minimize conflict between disposal buoy positions and submarine fraffic to 

 and from the U.S. Navy Base in Groton, CT. The state boundary affects state regulatory 

 authority under the Coastal Zone Management Act (CZMA) and the issuance of state water 

 quality certification for disposal permits (Carey 1998). 



Monitoring of the impacts associated with the subaqueous disposal of sediments 

 dredged from harbors, inlets, and bays in the New England region has been overseen by the 

 Disposal Area Monitoring System (DAMOS) Program since its inception in 1977. The goals 

 of the DAMOS Program pertain to detailed investigation and reduction of any adverse 

 physical, chemical, and biological effects on the marine environment associated with 

 dredged material disposal activities. The monitoring sponsored by DAMOS helps to ensure 

 that the effects of sediment deposition over pre-defined areas of seafloor are local and 

 temporary. A flexible, tiered management protocol is applied in the long-term monitoring of 

 sediment disposal at ten open- water dredged material disposal sites along the coast of New 

 England (Germano et al. 1 994). 



In recent years, management objectives have sought to minimize the lateral spread of 

 dredged material during placement at NLDS by taking advantage of the topography of the 

 site through filling in depressions between historic disposal mounds. This approach has the 

 dual advantage of maximizing site capacity while minimizing volumes of capping dredged 

 material (CDM) required to completely cover and contain an unacceptably-contaminated 

 dredged material (UDM) deposit (Fredette 1994). Additionally, in order to reduce the effects 



Monitoring Cruise at the New London Disposal Site, August 2000 



