other replicates. Two other USCGA stations (150S and 50S) also had evidence of low 

 apparent dissolved oxygen and the absence of Stage III organisms, resulting in lower OSI 

 values. A median value of +5 was derived for Station 150S and +6 was calculated for 

 Station 50S. Sediment methane was noted at one replicate image at Station 50W; however, 

 the presence of Stage III organisms buffered the effect on the OSI for that station. 



3.3 NL-94 Disposal Mound 



3.3.1 Bathymetry 



The NL-94 mound was formed when 37,000 m 3 of material from the U.S. Navy 

 Submarine Base was released at the NDA 94 buoy. The disposal activity was concentrated 

 around the NDA-94-1 buoy position. As a result, the August 1995 precision bathymetric 

 survey was successful in detecting this small deposit (Figure 3-35). A 0.48 km 2 area of 

 detailed analysis was selected around the active disposal point to conduct precision depth 

 difference calculations. 



The deposition of material at the NDA-94-1 buoy resulted in the formation of a 

 disposal mound approximately 125 m wide and 0.9 m high (Figure 3-39). A flat tongue of 

 dredged material with a maximum height of 0.4 m extended 140 m southeast from the apex 

 of the mound. This southeast tongue of the NL-94 mound abutted the historic NL-I mound 

 (Figure 3-35). 



3.3.2 REMOTS® Sediment-Profile Photography 



A series of REMOTS® sediment-profile photographs were collected over the NL-94 

 mound in August 1995 and September 1997 to document the lateral extent of dredged 

 material within close proximity to the NDA-94-1 disposal buoy position, as well as assess 

 the benthic recolonization status of the surficial sediments. A complete set of REMOTS® 

 image analysis results for the NL-94 mound are presented in Appendix B. 



3.3.2.1 August 1995 Survey 



The center station (CTR) and six surrounding stations (all within 50 m of the center) 

 had dredged material, with the thickness of the dredged material layer at each station 

 exceeding the penetration depth of the camera prism. Twelve of the fifteen REMOTS® 

 stations had recently placed dredged material present, while three of the stations had either 

 ambient sediment or historic dredged material. At Stations 150NW, 100SW, and 150SE, 

 one or two of the replicate photographs displayed dredged material layer thickness greater 

 than or equal to the penetration depth of the camera prism. At Stations 150NW and 



Monitoring Cruise at the New London Disposal Site, 1992 - 1998 



