21_ 



and SP) and along the east-southeast valley area to determine recolonization status and 

 relative shear strength of the sediments (Figure 3-2; Appendix C Table 2). 



3.2.2 Precap Survey 



SAIC conducted a second REMOTS® survey on 3-4 November 1993 following the 

 completion of the inner harbor dredging. Transects were oriented in the eight major 

 compass directions (N, NE, E, SE, S, SW, W, NW) to delineate the apron of the disposal 

 mound for capping. The survey was conducted from the center of the mound 

 (41°09.100' N, 72°53.442' W) as determined by the interim disposal survey. Each 

 transect began 325 m from the center and consisted of four stations spaced 75 m apart 

 extending a total of 550 m from the center. Three replicate samples were taken at each 

 station. The presence and/or absence of dredged material was determined for each 

 REMOTS® sediment-profile photograph (Figure 3-2). 



In addition to the eight directional transects, two other stations in the southwest 

 quadrant were also sampled, 400 m SSW and 400 m WSW, during the precap survey 

 (Appendix C Table 2). The southwest quadrant may be selected as a site for future 

 disposal operations, and information from these stations was used to provide greater detail 

 on the distribution of dredged material and status of the benthic community. A nine-station 

 cross-shaped grid was conducted over the historic FVP mound in the northeast corner of 

 the disposal site. The REMOTS images were used to determine whether excess cap 

 material should also be directed to the FVP mound (Appendix C Table 3). 



3.3 Geotechnical Cores/Surface Grabs 



Geotechnical cores were obtained in a joint effort between SAIC and the University 

 of Rhode Island (URI) using the PVC version of the Marine Geotechnical Laboratory 

 (MGL) Large-diameter Gravity Corer (LGC) (Appendix D Table 1 , and Figures 1 through 

 3) (Silva et al. 1994a). The core barrel consisted of a 3 m (10 ft) section of Schedule 40 

 PVC with a 10.2 cm (4.0 in) inside diameter. The PVC core barrel included a nose cone 

 and core catcher at the bottom. Basement sediments were cored during the baseline and 

 precap surveys to establish geotechnical characteristics before loading by any additional 

 layers of material. During each interim survey (i.e., disposal and capping) sediment grabs 

 were collected from the vicinity of the NHAV buoy and the center of the disposal mound 

 to characterize the surface sediments (Figure 1-2; Appendix D Table 2). 



Basement material, UDM, and CDM were cored immediately following completion 

 of the CAD mound to establish the initial geotechnical characteristics of the completed 

 mound (Figure 1-2). These data will be used as a reference for future geotechnical 



Monitoring Surveys of the New Haven Capping Project, 1993-1994 



