2.0 METHODS 



2.1 Time Line 



The time line of 1996/1997 disposal activities and 1997/1998 monitoring surveys at 

 WLIS is displayed on Figure 2-1. The reference area investigation was delayed in 

 September because abundant lobster gear in the area obstructed survey lanes and posed a 

 hazard to survey instruments. The investigation was completed in March 1998. The 

 1996/1997 disposal activities resulted in the formation of the I mound (Figure 2-2). The 

 1997/1998 disposal activities formed the J mound which will be discussed in the next 

 WLIS report. Figure 2-3 shows the time line for the 1995/1996 disposal season that 

 created the H mound. 



2.2 Survey Area 



In order to fulfill the objectives of the 1997 WLIS monitoring survey, SAIC 

 conducted a comprehensive field effort consisting of precision bathymetry and REMOTS® 

 sediment-profile photography surveys. The bathymetric survey at WLIS was performed 

 over an 800 x 800 m area centered at the 1996 disposal buoy position, 40°59.203' N, 

 73°29.072' W (Figure 2-4). The survey covered a total of 25 survey lanes, oriented 

 east/west, with 25-m lane spacing. By comparing current results with those of previous 

 surveys, the size and shape of the new mound was quantified and graphically represented. 



2.3 Navigation 



Bathymetric data were collected with SAIC's Integrated Navigation and Data 

 Acquisition System (INDAS) to insure accurate comparisons with prior datasets. The 

 system utilizes a Hewett-Packard 9920® series computer to provide real-time navigation 

 and collect position, depth, and time data for later analysis. The Del Norte Trisponder® 

 System provided positioning data to an accuracy of ±3 m in the horizontal control of 

 North American Damm of 1927 (NAD 27) by referencing to shore stations established 

 along the Coimecticut coast at the known benchmarks of Norwalk Harbor Power Plant 

 (41°04.248' N, 73°24.501' W) and Greenwich Point (41°00.580' N, 73°34.193' W). A 

 detailed description of the navigation system and its operation can be found in SAIC 

 Report No. 290 (Murray and Selvitelli 1996). Bathymetric surveys at WLIS currently are 

 conducted using NAD27 and the Del Norte navigation system for comparability with 

 previous datasets and master grid. Before a transition can be made to the more recent 

 North Atlantic Damm of 1983 (NAD83) using differential Global Position System 

 (DGPS), a new master grid of the disposal site must be generated with this advanced 

 technology. 

 Monitoring Cruise at the WLIS Disposal Site, September 1997 and March 1998 



