precision bathymetric survey at this site to better define the 

 extent of the historic disposal mound. The ORE system included a 

 transceiver capable of outputting signals of 10 kw at frequencies 

 from 1 to 12 kHz that would allow optimal penetration of the 

 sediment. The over-the-side vehicle contained a 3.0 to 7.0 kHz 

 transducer and a 12 kHz transducer. Synchronous printout of the 

 position and marking of the record was accomplished in the same 

 manner as during the side scan surveys at the other areas. 



The side scan data from the Brenton-A, Brenton-B, and 

 Prudence areas and the sub-bottom data from the Brenton Reef site 

 were analyzed and interpreted by Dr. Nancy Neff , a geologist at the 

 University of Rhode Island (URI) . In addition, Dr. Neff analyzed 

 and integrated results from approximately 75 km of high resolution 

 sub-bottom reflection (Uniboom) profiles in the vicinity of the 

 Brenton-A and Brenton-B areas in order to describe the 

 sedimentological history of each area. These Uniboom profiles had 

 been obtained previously by URI scientists as part of a project 

 sponsored by the Minerals Management Service (MMS) . 



2.4 REMOTS® Sediment Profile Photography 



REMOTS® photos were obtained at the Brenton Reef disposal 

 site using a Benthos Model 3731® Sediment-Profile Camera (Benthos, 

 Inc. , North Falmouth, MA) . The REMOTS® camera is designed to 

 obtain in-situ profile images of the top 15-20 cm of sediment. A 

 detailed description of REMOTS® camera operation and image analysis 

 is presented in DAMOS Contribution #60 (SAIC, 1989) . 



The purpose of the REMOTS® survey conducted on 13-14 

 October was to map the areal extent of the historically-deposited 

 sediment and to evaluate sediment types and benthic habitat 

 conditions at the Brenton Reef site. Stations were located in an 

 irregular grid centered near the western disposal site boundary to 

 allow evaluation of the areal limits of the historically-deposited 

 sediment (Figure 2-3) . One out of two REMOTS® photographs was 

 analyzed from each grid station, and three replicate photographs 

 were analyzed at each of two reference stations (SE-REF and WEST-2) 

 located outside but near the disposal site. 



2.5 Sediment Sampling and Analysis 



A 0.1 m 2 Smith-Mclntyre grab sampler was used to collect 

 a total of 12 sediment samples at the Brenton A site, 15 samples at 

 the Brenton B site (Figure 2-1) , and 9 samples at the Prudence site 

 (Figure 2-2) . In addition, 10 sediment samples for grain size and 

 chemical analyses were obtained in and around the Brenton Reef 

 historic disposal site (Figure 2-4) . The exact locations of the 

 samples at each surveyed area were determined after examination of 

 the side scan records; stations were located to verify the sediment 



