2.0 METHODS 



2.1 Survey Area 



In order to fulfill the objectives of the 1996 CLIS monitoring survey, a bathymetric 

 survey area was defined to examine the CLIS 95, CLIS 94, NHAV 93, and MQR mounds. 

 The July 1996 bathymetric survey over CLIS occupied a2100mx2100m area, centered 

 at 41 °08.990' N, 72°53.272' W (NAD 27). A total of 85 survey lanes at 25 m lane 

 spacing were required to delineate the topography of the four disposal mounds of interest 

 (Figure 2-1). Detailed bathymetric charts were generated for the 4.41 km^ survey area as 

 well as four areas of concentrated analysis to accurately quantify mound height, lateral 

 spread of dredged material, consolidation, and position relative to other disposal mounds. 



2.2 Navigation 



In an effort to provide strong comparisons with historic data sets, bathymetric data 

 were collected with the use of SAIC's Integrated Navigation and Data Acquisition System 

 (INDAS). This system utilizes a Hewlett-Packard 9920® series computer to provide real- 

 time navigation, as well as collect position, depth, and time data for later analysis. A Del 

 Norte Trisponder® System provided positioning data to an accuracy of ±3 m in the 

 horizontal control NAD 27. Shore stations were established along the Connecticut coast at 

 the known benchmarks of Stratford Point (41°09.112' N, 72°06.227' W) and Lighthouse 

 Point (41° 14. 931' N, 72° 54. 255' W) (Figure 1-2). A detailed description of the 

 navigation system and its operation can be found in the DAMOS Navigation and 

 Bathymetry Reference Report (Murray and Selvitelli 1996). 



In order to maximize the efficiency of survey operations at CLIS, differential 

 Global Positioning System (DGPS) data in conjunction with SAIC's Portable Integrated 

 Navigation and Survey System (PINSS) were used to position the survey vessel over the 

 July 1996 REMOTS® camera stations. A Magnavox 4200D GPS receiver and a Magnavox 

 MX50R differential beacon receiver provided DGPS positioning data to PINSS in the 

 horizontal control of North American Datum of 1983 (NAD 83) to an accuracy of +5 m. 

 The Coast Guard differential beacon broadcasting from Montauk Point, Long Island, New 

 York, (293 kHz) was utilized for satellite corrections due to its geographic position relative 

 to CLIS. 



The target REMOTS® station locations were calculated in NAD 27, then converted 

 to NAD 83 for real-time navigation with the use of the US Army Topographic Engineering 

 Center's CORPSCON version 3.01. The acmal positions of the REMOTS® replicate 



Monitoring Cruise at the Central Long Island Sound Disposal Site, July 1996 



