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2.0 METHODS 



Over the period 1992 to 1998, four environmental monitoring surveys occurred at 

 the NLDS. In general, field surveys under the DAMOS program are conducted in the 

 summer, following the dredged material disposal season (1 October to 31 May), to verify 

 placement of materials and evaluate environmental effects associated with the disposal 

 activities. Typical survey objectives include determining the distribution of dredged 

 material on the seafloor and progress in recolonization by benthic organisms. 



Precision bathymetry and REMOTS® sediment-profile photography have been 

 employed as the standard tools for tracking the placement of dredged material, examining 

 long term fate of individual sediment deposits, and assessing biological conditions at the 

 disposal sites relative to nearby reference areas. These methods were developed in the 

 context of a rigorous tiered monitoring approach (Germano et al. 1994). Utilizing these 

 monitoring techniques, comprehensive monitoring surveys were conducted at NLDS in 

 August 1992, August 1995, September 1997, and July 1998 (Table 2-1). The bathymetric 

 and REMOTS® sediment-profile photography survey grids at NLDS varied from year to 

 year based on changes in the active areas within the disposal site and the overall 

 management strategy. 



2.1 Bathymetry and Navigation 



This report chronicles six years (1992-1998) of disposal and survey activity at 

 NLDS. Within this time period, the instrumentation and analysis procedures employed by 

 SAIC evolved in a manner that best utilized advances in technology and presentation of 

 data. This evolution was tightly controlled in order to increase the efficiency of survey 

 operations while continuing to provide accurate and comparable data relative to previous 

 monitoring surveys. 



Since the inception of the DAMOS Program, all survey results and reported station 

 locations have been referenced to the North American Datum of 1927 (NAD 27). As the 

 use of high precision Differential Global Positioning System (DGPS) data has become 

 more widespread, an effort to utilize the most recent datum (the North American Datum of 

 1983 [NAD 83]) has been instituted. Consequently, this document transitions between the 

 use of NAD 27 and NAD 83 at NLDS. All survey results, reported station locations, and 

 disposal site boundaries pre-dating the 1997 Master Bathymetric survey, are referenced to 

 NAD 27 unless otherwise noted. 



Monitoring Cruise at the New London Disposal Site, 1992 - 1998 



