2.0 METHODS 



2.1 Bathymetry and Navigation 



The SAIC Integrated Navigation and Data Acquisition System (INDAS) provided the 

 precision navigation required for all field operations. This system used a Hewlett-Packard 

 9920® series computer to collect position, depth, and time data for subsequent analysis, as 

 well as providing real-time navigation. A Del Norte Trisponder® System provided 

 positioning to an accuracy of ±3 m. Shore stations were established in Coimecticut at 

 known benchmarks at Stratford Point (41°9.112' N and 73°6.227' W) and Lighthouse Point 

 (41°14.93r N and 72°54.255' W). A detailed description of the navigation system and its 

 operation can be found in DAMOS Contribution No. 60 (SAIC 1989). 



An ODOM DF3200 Echotrac® Survey Fathometer with a narrow-beam 208 kHz 

 transducer measured individual depths to a resolution of 3.0 cm (0.1 feet). Depth values 

 transmitted to the computer were adjusted for speed of sound and transducer depth. Prior to 

 starting the 1990 precision bathymetric survey, an Applied Microsystems, Ltd. Model STD- 

 12 CTD probe was used to obtain a sound velocity profile. A complete description of this 

 instrument is given in DAMOS Contribution No. 66 (SAIC 1990b). During analysis, raw 

 bathymetric data were standardized to Mean Low Water by correcting for changes in tidal 

 height during the survey. A detailed discussion of the bathymetric analysis technique is 

 given in DAMOS Contribution No. 60 (SAIC 1989). ■ 



The July 1990 bathymetric survey of the northwest comer of CLIS encompassed a 

 1200 X 1200 m grid centered at coordinates 41°9.260' N and 72°53.353' W. The survey 

 consisted of 49 lanes run east and west at 25 m lane spacing. 



2.2 REMOTS® Sediment-Profile Photography 



REMOTS® photography detected the distribution of thin (1 to 20 cm) dredged 

 material layers, mapped benthic disturbance gradients, and monitored the process of infaunal 

 recolonization on, and adjacent to, the disposal moimd. A detailed description of REMOTS® 

 photograph acquisition, analysis, and interpretive rationale is given in DAMOS Contribution 

 No. 60 (SAIC 1989). 



The 66 REMOTS® stations occupied at CLIS in July 1990 were 100 m apart and set 

 up in two grids east and west of the CLIS-89 disposal buoy location (Figure 2-1). Each 

 station consisted of three replicate photographs. In addition to the stations within CLIS, 

 three reference areas allowed a comparison between ambient and on-site conditions (Figure 

 2-1). The reference areas were 2500 m west (2500W), 4500 m east (4500E), and 5094 m 

 southeast (CLIS-REF) of the CLIS-87 buoy location. Each reference area contained 13 



Monitoring Cruise at the Central Long Island Sound Disposal Site. July 1990 



