MONITORING CRUISE AT THE NEW LONDON DISPOSAL SITE 

 JULY 1987 



1 . INTRODUCTION 



The New London Disposal Site covers a one square 

 nautical mile area located approximately two nautical miles south 

 of the mouth of the Thames River, CT. This site, centered at 

 latitude 41°16.1 I N and longitude 72°04.6'W, has been monitored 

 since 1977. It has received an average of approximately 150,000 

 m (200,000 yds ) of dredged material annually. 



During the period 24 July to 1 August 1987, field 

 operations were conducted at the New London Disposal Site to 

 provide information related to the environmental effects of 

 dredged material disposal. The field operations included 

 precision bathymetric and sediment-profile photographic (REMOTS ) 

 surveys, sediment sampling for chemical and physical analysis, 

 collection of a dominant suspension-feeding organism for 

 bioaccumulation analysis of selected contaminants, and 

 measurement of temperature, salinity, and dissolved oxygen in the 

 water column at the disposal and reference sites. The primary 

 objectives of this study were to: 



■ Delineate the extent and topography of the dredged 

 material deposited at the site; 



■ Obtain sediment and tissue samples of a dominant 

 suspension-feeding organism along the axis of 

 predominant water movement to provide an initial 

 assessment of the relationship between sediment 

 contamination and biological uptake; and 



■ Characterize the depth gradient in dissolved oxygen and 

 assess near-bottom dissolved oxygen concentrations 

 relative to REMOTS benthic analyses at the disposal 

 and reference sites. 



2 . METHODS 



2 . 1 Bathymetry and Navigation 



The precise navigation required for all field 

 operations was provided by the SAIC Integrated Navigation and 

 Data Acquisition System (INDAS) . This system uses a Hewlett- 

 Packard 9920 series computer to collect position, depth, and time 

 data for subsequent analysis, as well as providing real-time 

 navigation. Positions were determined to an accuracy of ±3 

 meters from ranges provided by a Del Norte Trisponder System 

 interfaced to the INDAS. For the present survey, shore stations 

 were established at known benchmarks at Millstone Point and New 

 London Light, CT. 



