EXECUTIVE SUMMARY 



The increased need for disposal of 

 material dredged from numerous 

 industrialized harbors in New England led 

 to experiments in covering, or capping, 

 contaminated material deposited on a level 

 seafloor with cleaner dredged material. 

 The assumption behind these experiments 

 was that a sufficiently thick layer of 

 sediment would isolate the contaminant 

 from the aquatic ecosystem. Capping 

 operations and associated monitoring 

 programs were conducted as part of the 

 Disposal Area Monitoring System 

 (DAMOS) Program, a regional program 

 initiated in 1977 by the New England 

 Division (NED) of the US Army Corps of 

 Engineers (US ACE). 



After more than 10 years of capping 

 operations, enough data had been collected 

 to warrant a retrospective volume. This 

 monograph was compiled from three 

 specific viewpoints : 



• a historical review of capping 

 operations from original 

 experiments in Long Island Sound 

 in 1979 to the present; 



• a synopsis of the viability of 

 capping as a dredged material 

 disposal alternative; 



• a practical description of capping 

 and monitoring techniques for 

 agencies considering this disposal 

 practice. 



concerns included the adequacy of the 

 available technology to point-dump; the 

 difficulties associated with discriminating 

 between cap and covered material; and the 

 possibility that, on impact, cap material 

 might displace the sediments to be 

 covered. Not only have the concerns been 

 addressed, but focusing on potential 

 operational problems has also improved 

 the techniques that have proved successful. 



This monograph focuses on four early 

 capping projects. A detailed record of both 

 disposal operations and subsequent 

 monitoring of these capped mounds 

 provides a checklist of recommendations 

 for a successful capping project. The 

 results of the first experimental capping 

 project (Stamford-New Haven), initiated in 

 1979, suggested that with careful 

 navigational controls point-dumping at a 

 taut-wired buoy could be used to form a 

 discrete mound of contaminated dredged 

 material. In addition, these results 

 suggested that precise deposition of 

 capping material, both at the center and at 

 the flanks of the mound of contaminated 

 material, could be accomplished with 

 careful navigation and project planning. 



A successful capping project requires 

 an effective monitoring program in 

 addition to pre-project planning and 

 organized dredging and disposal 

 operations. The DAMOS Program 

 initiated a three-pronged approach to 

 monitoring: 



When capping was first considered, 

 technical operations were organized to 

 address specific concerns formalized by 

 the USACE after extensive consultation 

 with the scientific community. These 



ensure physical stability and 

 complete cap coverage of the 

 mounds; 



