LORAN-C time delay numbers for the center of the disposal site. 

 Given the precision of LORAN-C (approximately 3 to 60 meters, 

 depending on the combination of slave stations used) and how close 

 to those numbers the scows actually get, disposal occurs in a 

 dispersed pattern around the true coordinates. This results in a 

 thin layer of material spread over much of the site. The high 

 energy regime at the site acts to move the material during 

 convective descent as well as after impact with the bottom. The 

 presence of sand and gravel throughout the majority of the site 

 suggests that the bottom current velocities are sufficient to 

 resuspend fine-grained material for transport in the predominant 

 directions of flow (northwest and southeast) . 



Because of the small volume of material deposited at 

 Cornfield Shoals over the last ten years, the disposal procedures 

 used, and dispersion, a thin layer (< 0.5 m) of dredged material 

 could have accumulated throughout much of the site and not be 

 detected by the visual comparison of the present survey with those 

 performed in 1978 and 1979. Detecting such thin layers would 

 normally be difficult even with computer-aided comparisons of 

 surveys due to relatively rapid changes in depth and an irregular 

 bottom topography. The 360,000 m^ of material deposited between 

 the 1978 and 1987 surveys would result in a layer of approximately 

 0.36 m if spread evenly throughout the survey area. At a 

 containment site, such as the Central Long Island Sound (CLIS) site 

 where point dumping occurs at a taut-moored disposal buoy, this 

 amount of material would have created a distinct mound 

 approximately 2 meters high with a radius of 150 to 200 meters. 

 The lack of a significant topographic feature at Cornfield Shoals 

 is most likely due to both the disposal procedures used and the 

 high energy regime responsible for dispersing the material. 



4 . REFERENCES 



NUSC, 1979. DAMOS Disposal Area Monitoring System Annual Data 

 Report: Proceedings of Symposium, 14-15 May 1979. Naval 

 Underwater SYstems Center, Newport RI. 



SAIC, 1986. Seasonal Monitoring Cruise at the New London Disposal 

 Site, July 1986. SAIC Report #86/7540&C60 , US Army Corps of 

 Engineers, New England Division, Waltham, MA. DAMOS 

 Contribution #60. 



