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5.0 CONCLUSIONS 



Evidence of active bed transport at CSDS prior to 1991 prompted concern over the 

 possible transport of suspended sediment north of the site and onto nearby oyster beds. The 

 present study, conducted during the disposal of sandy and fine-grained dredged materials, 

 concluded that: 



The predominant transport direction at the site appears to be east-west. This is 

 supported by current meter deployments and observed erosion and deposition patterns. 



Sediment disposed at the site was not immediately dispersed and was defined within 

 discrete deposits. This was observed for both fine-grained and sandy sediments. 



The dispersion process appears to occur over a period of weeks to months. The 

 dispersion rate for fine-grained materials may be markedly slowed by sand armor that 

 migrates over the more cohesive, less erosive silt-clays. 



The above findings, taken over the ten-month time period, reduce concerns about far-field 

 transport of material over oyster beds to the north. The dispersion of material over a time 

 scale of years, and the effectiveness of the sand armor over the silt-clays, are unknown. 





Synthesis of Monitoring Surveys at the Cornfield Shoals Disposal Site, July 1991 to May 1992 



