REPORT DOCUMENTATION PAGE 



Form approved 

 OMB No. 0704-0188 



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 data sources, gathering and measuring the data needed and correcting and reviewing the collection of information. Send comments regarding this burden estimate or 

 any other aspect of this collection of information including suggestions for reducing this burden to Washington Headquarters Services, Directorate for information 

 Observations and Records, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302 and to the Office of Management and Support, Paperwork Reduction 

 Project 10704-0188), Washington, DC. 20S03. 



1. AGENCY USE ONLY (LEAVE BLANK) 



2. REPORT DATE 



October 1995 



(3. REPORT TYPE AND DATES COVERED 



Final report 



. TITLE AND SUBTITLE 



Deep Water Capping 



5. FUNDING NUMBERS 



6. AUTHOR(S) 



Mary Baker Wiley 



. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 



Science Applications International Corporation 

 221 Third Street 

 Newport, Rl 02840 



8. PERFORMING ORGANIZATION REPORT 

 NUMBER 



SAIC-91/7609&C96 



9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 



US Army Corps of Engineers-New England Division 

 424 Trapelo Road 

 Waltham, MA 02254-9149 



10. SPONSORING/ MONITORING AGENCY 

 REPORT NUMBER 



DAMOS Contribution 

 Number 98 



11. SUPPLEMENTARY NOTES 



Available from DAMOS Program Manager, Regulatory Division 

 USACE-NED, 424 Trapelo Road, Waltham, MA 02254-9149 



12a. DISTRIBUTION/AVAILABILITY STATEMENT 



Approved for public release; distribution unlimited 



12b. DISTRIBUTION CODE 



13. ABSTRACT (MAXIMUM 200 WORDS) 



The Boston Harbor Navigation Improvement project will generate an estimated 2.2 xlO^m 3 of dredged material . 



Approximately 500,000 m 3 of this sediment is expected to be unsuitable for unconfined open water disposal. One alternative 

 proposed was that the unsuitable sediments be deposited at the existing Massachusetts Bay Disposal Site (MBDS), where they 



would be capped by the remaining 1.7 x 10^ m 3 of clean dredged material. Successful disposal of contaminated dredged 

 material at open ocean sites requires formation of a distinct dredged material mound, careful placement of capping materials, 

 and bathymetric and environmental monitoring to ensure that the operation is successful initially and effective over the long 

 term. 



MBDS is a disposal site approximately 17 nmi east-northeast of Boston Harbor in water depths averaging 90 m. This 

 site is deeper than existing disposal sites in Long Island Sound where capping operations have occurred in a maximum of 

 approximately 25 m water depth. Several concerns have been raised regarding proposals to extend the depth of capped 

 disposal operations to deeper waters (e.g., Dolin and Pederson 1991). Monitoring of disposal at MBDS over the past 7 years 

 has shown that dredged material released at the site does form a distinct disposal mound which can be detected by acoustic 

 bathymetry. The formation of a well-defined disposal mound has been the criterion on which capping decisions have been 

 made at shallower sites. 



Such a formation indicates that the dredged material is stable and distinct from the ambient sediment. If the dredged 

 material forms a distinct, stable mound, then the following conditions can be satisfied: the sediment is being contained at the 

 site; the area over which capping material must be placed is known; and the capped mound can be monitored to verify that the 

 cap is isolated the unsuitable sediments effectively. Based on the past disposal at MBDS, as well as deep water sites 

 (>100m) in Puget Sound, we can predict that the dredged material will form a well-defined mound at these depths and that 

 capping can be viable means of containing unsuitable sediments at these sites. 



14. SUBJECT TERMS 



capping disposal mound MBDS sediments bathymetry 



15. NUMBER OF PAGES 



35 



16. PRICE CODE 



17. SECURITY CLASSIFICATION OF REPORT 18. SECURITY CLASSIFICATION OF THIS 19. SECURITY CLASSIFICATION OF 



Unclassified page abstract 



20. LIMITATION OF ABSTRACT 



