System (INDAS) . This system uses a Hewlett-Packard 9920 Series 

 computer to collect position, depth, and time data as well as to 

 provide real-time navigation. During a bathymetric survey, a 

 display is provided to the helmsman of the research vessel with the 

 survey lanes and the real-time position of the vessel indicated. 

 The positional information is recorded on magnetic disk every 

 second along with depth and time. The computer system calculates 

 accurate positions from the range data provided by the positioning 

 system and is capable of converting from state plane coordinates 

 in the Transverse Mercator system to Lambert or Mercator 

 coordinates. 



Positions were determined to an accuracy of ±3 meters 

 from ranges provided by a Del Norte Trisponder System. Shore 

 stations were established in Connecticut over known benchmarks at 

 Stratford Point and Lighthouse Point. These shore stations were 

 same ones used in previous years to allow accurate comparisons of 

 seasonal surveys . 



2.2 Bathymetric and Side Scan Sonar Surveys 



Depths were determined to a resolution of 0.3 meters (0.1 

 ft) using a Raytheon DE-719 Precision Survey Fathometer with a 208 

 kHz transducer. The fathometer was calibrated with a bar check at 

 fixed depths below the transducer before the survey began. A 

 Raytheon SSD-100 Digitizer was used to transmit the depth values 

 to the SAIC computer system. Analysis of the bathymetric data 

 corrects the raw depth values to Mean Low Water by adjusting for 

 ship draft and for tidal changes for the duration of the survey. 

 Noise generated in the data from fluctuating environmental 

 conditions can result in errors such as spurious shallow depths. 

 All data points in terms of depth and position were checked for 

 such unreasonable values so that the final contour plots would not 

 contain errors. 



For the 1986 field operations, survey lanes were run east 

 and west at 50 meter lane spacing over the entire CLIS disposal 

 area. Surveys also were conducted over the ten individual disposal 

 mounds (MQR, STNH-N, STNH-S, Norwalk, NH-74, NH-83, CS-1, CS-2, FVP 

 and the new CLIS-86 mound) at 25 meter lane spacing. The closer 

 lane spacing at these mounds provided good resolution for 

 subsequent data analysis and the production of detailed depth 

 contour charts. 



The bathymetric surveys conducted at Ghost Sites 1 and 

 2 were run at 25 meter lane spacing over 600 by 600 meter areas 

 centered at 41°8.96'N, 72°51.36 I W (Ghost 1) and 41°9.64'N, 



