73 



Factors contributing to the wide distribution of dredged material include the depth at the 

 disposal point (70 m) and the wide area of coverage by the conventionally moored buoy 

 (SAIC 1992). 



To assess the extent of dredged material dispersion when the barges released material, 

 SAIC conducted a plume tracking study. Previous estimates of material remaining in the 

 water column range from 1 to 5% of the volume of material disposed (Truitt 1986 and 

 references therein). Results from the plume tracking study showed that if disposal occurred 

 only on maximum flood tide (a worst case), an estimated 6% of the material would be 

 transported outside of the disposal site. However, when disposal occurred evenly at all 

 stages of the tide, the estimate would be reduced to 0.8%. When there is a need to minimize 

 the distribution of dredged material in the water column, disposal operations should be 

 scheduled to avoid peak flood tide (SAIC 1988a). 



REMOTS® analyses conducted in 1989 at RDS revealed that much of the area 

 affected by disposal operations since 1984 had undergone rapid recolonization by benthic 

 organisms. Due to the relatively uncontaminated character of the dredged sediments and the 

 intermittent nature of disposal at RDS, monitoring efforts have not been as intensive as at 

 other sites in New England. 



6.6.3 References for Section 6.6 



SAIC. 1988a. A summary of DAMOS physical monitoring of dredged material disposal 



activities. SAIC Report No. SAIC-88/7527&C71. Final report submitted to US Army 

 Corps of Engineers, Waterways Experiment Station, Vicksburg, MS. 



SAIC. 1988e. Distribution of dredged material at the Rockland Disposal Site, May 1985. 

 DAMOS Contribution No. 50 (SAIC Report No. SAIC-85/7533&C50). US Army 

 Corps of Engineers, New England Division, Waltham, MA.. 



SAIC. 1992. Monitoring surveys at the Rockland Disposal Site, June 1989. DAMOS 



Contribution No. 83 (SAIC Report No. SAIC-89/7568&C81). US Army Corps of 

 Engineers, New England Division, Waltham, MA. 



Truitt, C. L. 1986. Fate of dredged material during open-water disposal. Tech. Note EEDP- 

 01-2. US Army Corps of Engineers, Waterways Experiment Station, Vicksburg, MS. 



DAMOS Summary Report, 1985-1990 



