2.0 METHODS 



Field operations were conducted over the Morris Cove borrow pit area aboard the 

 MA^ Beavertail on September 28, 2000 and October 2, 2000. Remote Ecological 

 Monitoring of the Seafloor (REMOTS®) sediment-profile photography was used in 

 conjunction with side-scan sonar, single beam bathymetry, and towed video to evaluate 

 benthic conditions within and adjacent to the borrow pit. Sediment profile images also were 

 obtained at a reference area located approximately 800 m to the west of the disposal buoy to 

 provide a comparison between ambient conditions and those existing within the borrow pit 

 (Figure 1-1). 



Navigation 



Differentially-corrected Global Positioning System (DGPS) data in conjunction with 

 Coastal Oceanographic's HYPACK® navigation and survey software were used to provide 

 real-time navigation to an accuracy of ±3 m. A Trimble 4000 RSi GPS receiver was used to 

 obtain raw satellite data and provide vessel position information in the horizontal control of 

 North American Datum of 1983 (NAD 83). The GPS receiver was interfaced with a Trimble 

 NavBeacon XL differential receiver to improve overall accuracy of the satellite data to the 

 necessary tolerances. The U.S. Coast Guard differential beacon broadcasting from Moriches, 

 NY (293 kHz) was utilized for real-time satellite corrections. 



The DGPS data were ported to HYPACK® data acquisition software for position 

 logging and helm display. Throughout the survey, individual stations and survey lanes were 

 selected and displayed in order to position the survey vessel at the correct geographic 

 location. All point sampling (REMOTS®) positions were logged with a time stamp in 

 Universal Time Coordinate (UTC) and a text identifier to facilitate Quality Control (QC) and 

 rapid input into a Geographic Information System (GIS) database. Position information was 

 logged continuously during the acquisition of survey lane data (side-scan sonar, bathymetry 

 profiles, and towed video footage). 



Side-scan Sonar 



A three-lane side-scan sonar survey was conducted over the Morris Cove borrow pit 

 to aid in defining the edges of the bottom feature, as well as provide additional information 

 pertaining to the distribution of dredged material. Side-scan sonar data was collected using a 

 Marine Sonic Technology PC Side-scan System operating at a frequency of 300 kHz. Three 

 longitudinal transects were completed over the burrow pit, with lane spacing and sonar range 

 controlled to maximize resolution and aerial coverage (Figure 2-1). After collection, the 

 side-scan data were used to develop a mosaic of the survey area. 



Monitoring Cruise at the Morris Cove Borrow Pit 



