EXECUTIVE SUMMARY 



Science Applications International Corporation (SAIC) conducted a monitoring 

 survey at the Western Long Island Sound Disposal Site (WLIS) from 16 to 18 September 

 1997 and from 5 to 6 March 1998 aboard the M/V Beavertail as part of the Disposal Area 

 Monitoring System (DAMOS) Program. Field efforts in September focused on the active 

 southwestern quadrant of WLIS and consisted of precision bathymetry and Remote 

 Ecological Monitoring of the Seafloor (REMOTS®) to monitor the development, stability, 

 and benthic conditions of the disposal mounds. The September 1997 survey documented 

 changes in bottom topography at the disposal area relative to July 1996. Approximately 

 35,000 m^ of dredged material was disposed on the WLIS seafloor during the 1996-1997 

 disposal season to form the I mound. Using REMOTS® sediment-profile photography, we 

 evaluated the benthic recolonization stams and sediment conditions of the new I mound and 

 the 1996 H mound, relative to reference areas, SOUTH and SW-REF. 



Additional field work was conducted from 5 to 6 March 1998 to investigate 

 potential sites for a new reference area and compare seasonal effects on benthic conditions 

 in REMOTS® photographs. At the present time, only two reference areas near WLIS have 

 been accepted to represent ambient conditions for the region. The DAMOS protocol 

 requires that three reference areas be used both for comparing the conditions between 

 ambient environments and dredged material disposal mounds, and for evaluation of 

 dredged sediments for disposal permits at WLIS. For the first time in DAMOS 's history, 

 a high-resolution side-scan sonar survey was used as a guide to locate and investigate a 

 potential reference area. The survey, conducted to the southeast of WLIS, proved valuable 

 in defining a large area that was relatively clear of historic dredged material deposits, 

 which are widespread in the regions surrounding WLIS. A 300 m radius region was 

 identified and referred to as SE-REF. To complete the March surveys, we revisited the 

 REMOTS® stations over the WLIS H and I disposal mounds. 



Buoys have been deployed to control disposal operations within the boundaries of 

 WLIS since its initiation as a regional dredged material disposal site in 1982 (WLIS III). 

 Since receiving the first volumes of sediment dredged from coastal Connecticut and New 

 York in 1982, WLIS has been monitored on a semi-annual basis for the U.S. Army Corps 

 of Engineers, New England District (NEA). Currently, a total of nine discrete disposal 

 mounds exist on the WLIS seafloor within an east-west trending seafloor depression that 

 extends through the center of the disposal site. The latest monitoring activity was 

 concentrated over the most recent dredged material deposits, the WLIS H and WLIS I 

 mounds, as well as the reference areas. 



Depth difference calculations and mapping of bathymetric data depicted the I mound 

 below the buoy location, 40°59.203' N, 73°29.072' W (NAD 27), between the D and G 

 mounds. The mound was 3.7 m high with a diameter of about 150 m. REMOTS® 

 sediment-profile photography indicated benthic recolonization of Stage I organisms in 



