The bathymetric survey was conducted at the New London 

 Disposal Site on 28 July 1987. Individual depth measurements were 

 determined to a resolution of 3.0 cm (0.1 feet) using a Raytheon 

 DE-719 Precision Survey Fathometer with a 208 kHz transducer. A 

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

 to the SAIC computer system. A more detailed description of these 

 systems is provided in DAMOS Contribution #48 (SAIC, 1985) . For 

 subsequent analysis procedures, the actual speed of sound in water 

 was determined from temperature and salinity data obtained using 

 an Applied Microsystems STD probe. Bathymetric survey lanes were 

 run east and west at a 25 meter lane spacing over a 1600 x 1600 

 meter area. The survey area encompassed the five disposal mounds 

 and included an area within the disposal site 530 m northwest of 

 the buoy, where 40% of the past year's dredged material presumably 

 was deposited due to miscommunication about the disposal point 

 (Figure 2-1) . This lane spacing provided adequate resolution for 

 subsequent data analysis and the production of detailed depth 

 contour charts. During data analysis, raw bathymetric data was 

 corrected to Mean Low Water by adjusting for both ship draft and 

 changes in tidal height during the survey. A detailed discussion 

 of the bathymetric analysis technique is given in DAMOS 

 Contribution #60 (SAIC, 1989) . 



2.2 REMOTS Sediment Profile Photography 



REMOTS sediment-profile photographic surveys of the New 

 London Disposal Site have been carried out since June 1984. 

 REMOTS photography is used to detect and map the distribution of 

 thin (1-2 0cm) dredged material layers. This capability 

 compliments the precision bathymetric data which can resolve 

 bottom elevation changes greater than 15 cm. In addition, REMOTS 

 is used to map benthic disturbance gradients and to monitor the 

 process of infaunal recolonization on and adjacent to disposal 

 mounds. A detailed description of REMOTS image acquisition, 

 analysis, and interpretative rationale is given in DAMOS 

 Contribution #60 (SAIC, 1989). 



Forty-one REMOTS stations were occupied on 27 and 29 

 July 1987 in and around the New London Disposal Site (Figure 

 2-2) . Three replicate images were obtained at each station 

 located in a 6 x 5 grid with 200 m spacing centered at the 

 disposal buoy. Additional stations were located at 800S (i.e., 

 800 meters south of station CTR) , 1000S, 600E, 1000E, 1500NW, 

 400NW, 400SE, and 800SE. In order to compare ambient and on-site 

 conditions, six replicate images were also obtained and analyzed 

 at each of three outlying reference stations (W-Ref, NE-Ref and 

 NLON-Ref ) . 



