EXECUTIVE SUMMARY 



Science Applications International Corporation (SAIC) conducted a monitoring 

 survey at the Central Long Island Sound Disposal Site (CLIS) from 10 to 18 July 1994 as 

 part of the Disposal Area Monitoring System (DAMOS) Program. The July 1994 field 

 operations were concentrated over the New Haven 1993 (NHAV 93) and Mill-Quirmipiac 

 River (MQR) disposal mounds and consisted of precision bathymetric, subbottom, surface 

 sediment characterization, and Remote Ecological Monitoring of the Seafloor (REMOTS®) 

 sediment-profile surveys, as well as grab sampling and geotechnical coring. These 

 surveying techniques were used to monitor the stability, cap thickness, and benthic 

 recolonization of the NHAV 93 and MQR mounds. 



In September 1993, two disposal buoys were deployed at CLIS. The NHAV buoy 

 was positioned at 41°09.122' N, 72°53.453' W in the center of a ring of disposal mounds 

 as part of a large scale confined aquatic disposal (CAD) project. The CDA buoy was 

 deployed over the previously capped MQR mound (41°08.637'N, 72°53.859'W) as part of 

 a de facto capping and cap augmentation project. Approximately 65,000 m' of sediment 

 was deposited at the CDA buoy, adding to the existing layers of dredged material that 

 compose the MQR mound. 



Since 1984, the management strategy at CLIS has been to develop a ring of disposal 

 mounds creating an artificial lateral containment cell for the deposition of large volumes of 

 dredged material. Utilizing the ten-year dredging cycle in the central Long Island Sound 

 region, the US Army Corps of Engineers, New England Division (NED) managed the 

 disposal of small to moderate volumes of material in order to fabricate a containment cell 

 at CLIS. During the 1993/94 New Haven Capping Project, this feamre received 

 approximately 590,000 m^ of unacceptably contaminated dredged material (UDM), 

 followed by 569,000 m^ of CDM. The ring of mounds greatly reduced the lateral spread 

 of the UDM mound apron, facilitating the efficient capping operations and yielding a flat, 

 stable CAD mound. 



During the 1993/94 disposal season, six bathymetric and two REMOTS® sediment- 

 profiling surveys were conducted over the NHAV 93 mound to monitor the progress of the 

 CAD mound construction. The latest field effort, four months after the completion of 

 capping operations, found no major topographic changes in the NHAV 93 mound in 

 comparison to the postcap bathymetric survey of March 1994. The MQR mound height 

 increased 1.5 m, creating a new apex, with no increase in overall diameter relative to the 

 bathymetric survey of December 1991. 



