u_ 



The 1992 monitoring scheme at NLDS was designed to verify the following 

 predictions based in part on the tiered DAMOS monitoring protocol: 



• Based on a disposal simulation model, sediment deposited in proximity to the 

 D/S buoy during the 1991-1992 season should result in the formation of a 

 capped mound having a radius of approximately 250 m; 



• A sediment cap of suitable material, 50-100 cm thick, should exist over the 

 material dredged from Dow Chemical Company and Stonington Harbor, CT; 



• Benthic recolonization over the active disposal area should consist primarily of 

 Stage I organisms (small pioneering polychaetes). Recolonization on the flanks 

 of the NL-91 and D/S mound complex and NDA disposal mounds and the 

 reference sites should be primarily Stage II and Stage III (tubicolous amphipods 

 and larger burrowing deposit feeders); 



• Near-bottom dissolved oxygen concentrations at stations within the disposal site 

 should be comparable to dissolved oxygen concentrations at reference area 

 stations. 



1.3.2 August 1995 Monitoring Survey 



A survey was conducted by SAIC at NLDS from 23 to 26 August 1995 aboard the 

 M/V UCONN. The survey investigated three capped mounds: the U.S. Coast Guard 

 Academy (USCGA) mound, the New London 1994 (NL-94) mound, and the NL-91 and 

 D/S mound complex. One mound that did not require capping was also surveyed, the New 

 London 1992 (NL-92) mound. The survey was designed to measure the areal extent of the 

 dredged material at the USCGA, NL-94 and NL-92 mounds, assess the recolonization 

 status of the benthic community at the capped mounds, and determine the effectiveness of 

 capping operations. 



Prior to the survey, predictions were made regarding the health of the benthic 

 community and the geometry of the disposal mounds (Germano et al. 1994). It was 

 expected that the benthic community at the most recent disposal mounds would be in the 

 early stages of recolonization. Benthic infauna at the NL-91 and D/S mound complex 

 were predicted to be similar to infauna at the reference areas. The data from this survey 

 showed that the benthic community at the most recent mounds and at the relic NL-91 and 

 D/S mound complex reflected ambient benthic conditions. Based on the amount of 

 material slated to be released at the buoys, mounds NL-94 and USCGA were predicted to 

 be 1.6 m high and 100 m wide (NL-94) and 4.5 m high and 300 m wide (USCGA) if 



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



