EXECUTIVE SUMMARY 



Science Applications International Corporation (SAIC) conducted a monitoring 

 survey at the Central Long Island Sound Disposal Site (CLIS) from 10 to 15 July 1996 

 aboard the M/V Beavertail as part of the Disposal Area Monitoring System (DAMOS) 

 Program. Field operations were concentrated over the new CLIS 1995 disposal mound, as 

 well as the historic New Haven 1993 (NHAV 93), CLIS 1994 (CLIS 94), and Mill- 

 Quinnipiac River (MQR) mounds. The July 1996 field effort consisted of precision 

 bathymetric and Remote Ecological Monitoring of the Seafloor (REMOTS®) surveys. 

 These surveying techniques were employed to monitor the development of CLIS 95, as 

 well as the stability, consolidation rates, and benthic recolonization of CLIS 94, NHAV 

 93, and MQR capped mounds. 



The CLIS 95 mound is the newest bottom feamre at the disposal site and is an 

 example of a small, capped, dredged material disposal mound. In September 1995, the 

 CDA buoy was deployed at 41°08.660' N, 72°53.042' W (NAD 27) approximately 

 450 m southwest of the historic NHAV 74 mound apex. An estimated barge volume of 

 16,300 m^ of unacceptably contaminated dredged material (UDM) was removed from 

 Milford and Bridgeport Harbors and deposited in close proximity to the CDA 95 buoy, 

 forming a small mound. The UDM deposit was then completely covered with 50,100 m^ 

 of capping dredged material (CDM) generated from dredging projects in the West River 

 and Bridgeport Harbor to yield a CDM to UDM ratio of 3. 1 : 1 .0. 



The results of the July 1996 field effort indicate the formation of a small, but 

 distinct, bottom feature on the CLIS seafloor. This discrete sediment mound was found to 

 be 3.75 m high at the apex and approximately 200 m in diameter. The CLIS 95 mound 

 has taken on a slightly irregular shape due to the slope of the bottom as well as the 

 distribution of capping material. REMOTS® photographs obtained over CLIS 95 

 documented deep Redox Potential Discontinuity (RPD) depths, mamre benthic infaunal 

 populations, and high Organism-Sediment Index (OSI) values, indicating rapid 

 recolonization of these sediments. 



No bathymetric data documenting the interim stages of development were available. 

 However, the compact nature of the deposit, the reported barge release positions, the CDM 

 to UDM ratio, and the results of the REMOTS® sediment-profile photography survey over 

 CLIS 95 suggest the UDM deposit has been completely capped. Continued monitoring of 

 the CLIS 95 mound is recommended for the next one to two years to document 

 consolidation and detect changes in benthic community structure. 



