1.0 INTRODUCTION 



Through the Disposal Area Monitoring System program 

 (DAMOS) , the New England Division of the Corps of Engineers has 

 been supporting a joint EPA-COE project at the Central Long 

 Island Sound (CLIS) disposal site since March 1982. A 

 description of the Field Verification Program (FVP) , the baseline 

 surveys and subsequent disposal site selection have been 

 presented in DAMOS Contribution #23 (SAIC, 1982) . To briefly 

 summarize the conclusions of that report, the FVP site (Figure 

 1-1) at the northeast corner of the CLIS open water disposal area 

 (41°9.39'N, 72"51. 75'W) is characterized by a flat, gently 

 sloping topography with the typical central Long Island Sound mud 

 bottom. The disposal site was considered to be very homogenous 

 and typical of natural sediments in the region (i.e., silt-clay 

 with subordinate modes of fine to coarse sand) . These 

 conclusions were reached based on sediment chemistry, diver 

 observations and the analysis of REMOTS® photographs. Suspended 

 sediment measurements indicated that the potential impact on the 

 FVP site of other proposed disposal operations in the southwest 

 corner of the CLIS disposal area would be negligible. 



Previous DAMOS operations have occurred in three 

 phases: the pre-disposal surveys, the disposal operation itself, 

 and the immediate post-disposal surveys that were conducted 

 through September 1983. The study included bathymetry and side 

 scan sonar measurements, diver observations, suspended sediment 

 measurements, REMOTS® profiling, sediment chemistry, sediment 

 density probe measurements and visual observations of cores, and 

 were reported in DAMOS Contribution #4 6, Volume II, Section III 

 (SAIC, 1984) . 



This report describes the monitoring studies conducted 

 since December 1984 utilizing bathymetric surveys conducted on 21 

 March and 22 October 1985, and REMOTS® photography conducted on 

 22 March, 26 June, and 23 October 1985. 



2 . BATHYMETRY 



A survey grid (Figure 2-1) was established consisting 

 of 33 transects, 800 meters long oriented in an east-west 

 direction and spaced 25 meters apart. All navigation control for 

 surveys and REMOTS® photography was provided by the SAIC 

 Navigation and . Data Acquisition System, a computerized control 

 unit interfaced to a Del Norte 54 microwave positioning system. 

 The SAIC system provides real time video displays of ship 

 position relative to designated lanes or locations which 

 substantially enhance the capability of the ship's helmsman to 

 steer survey lanes within ± 5 meters and to obtain replicate 

 sediment samples within ± 10 meters. This precision in ship 

 control is an essential requirement for this program, since the 

 disposal mounds are quite small and spatial variability in 



