REPORT DOCUMENTATION PAGE 



form approved 



OMB No. 0704-0 IS 



Public reporting concern for the collection of information is estimated to average 1 hour per response including the time for reviewing instructions, 

 searching existing 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 (0704-0188), Washington, DC. 20503. 



1. AGENCY USE ONLY (LEAVE BLANK) 



2. REPORT DATE 



December 2001 



3. REPORT TYPE AND DATES COVERED 



FINAL REPORT 



4. TITLE AND SUBTITLE 



Monitoring Cruise at the New London Disposal Site, 1992-1998. Volume II, Seawolf Mound 



6. AUTHOR(S 



Science Applications International 



5. FUNDING NUMBERS 



PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 



Science Applications International Corporation 

 221 Third Street 

 Newport, RI 02840 



8. PERFORMING 

 ORGANIZATION REPORT 

 NUMBER 



SAIC No. 525 



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



US Army Corps of Engineers-New England Division 

 696 Virginia Road 

 Concord, MA 01742-2751 



10. SPONSORING/MONITORING 

 AGENCY REPORT NUMBER 



DAMOS Contribution Number 132 



11. SUPPLEMENTARY NOTES 



Available from DAMOS Program Manager, Regulatory Division 

 USACE-NAE, 696 Virginia Road, Concord, MA 01742-2751 



12a. DISTRIBUTION/AVAILABILITY STATEMENT 



Approved for public release; distribution unlimited 



12b. DISTRIBUTION CODE 



13. ABSTRACT Monitoring surveys of the U.S. Navy Seawolf Mound within the New London Disposal Site (NLDS) were conducted in 

 September 1997 and July 1998. Field operations included data collection of one or more of the following: precision bathymetric surveys, Remote 

 Ecological Monitoring of the Seafloor (REMOTS), sediment-profile surveys, grab sampling of benthic invertebrates, and sediment coring. This 

 report summarizes the disposal and monitoring activities at the Seawolf Disposal Mound from 1995-1998. A companion report, Volume I, covers 

 monitoring conducted at other mounds in the site from 1992-1998. 



The NLDS has been used for on-going disposal throughout the 1990's, including unconfined disposal of suitable sediments, and capped disposal 

 of unsuitable sediments. During 1995-1996, the NLDS received a total barge volume of 877,500 m 3 of dredged material generated from three 

 separate projects (Seawolf, Venetian Harbor and Mystic River) in the eastern Long Island Sound region. Disposal resulted in creation of one 

 disposal mound, the U.S. Navy Seawolf Mound, consisting of unsuitable dredged material (Thames River channel and berthing areas, and 

 Mystic River) and suitable cap material (Thames River channel, Venetian Harbor and Mystic River). 



Bathymetric surveys, REMOTS data and sediment core data confirmed that the Seawolf Mound was capped with at least 50 cm of suitable 

 dredged material. The Seawolf Mound formed a flat, nearly circular deposit with a diameter of approximately 600 m. After an initial period of 

 consolidation (9 months to 1 year), the mound settled to an average height of 2 m with a small oval apex of 3 m. Across the surface of this 

 mound, a layer (0.5-3 m) of suitable material formed a cap consisting of sandy sediments and gray glacial clays from improvement dredging in 

 the Thames River channel. Based on visual analysis and benthic sampling, recolonization of the fresh dredged material by marine invertebrates 

 proceeded as expected with biological characteristics similar to NLDS reference areas. 



Physical and chemical analysis of sediment cores collected in 1997 and 1998 confirmed that the top 50 cm of the mound was chemically consistent 

 with the suitable capping material. There was no evidence of migration or release of contaminants from layers beneath the cap. Only long cores 

 (>2m) clearly penetrated beneath the cap into either ambient sediments or unsuitable material. These results are consistent with the conclusion 

 that the cap is a stable, thick layer that has effectively isolated the unsuitable sediments from the environment of Long Island Sound. 



14. SUBJECT TERMS DAMOS, Seawolf, Sediment Cores, Capping, Benthic Recolonization 



15. NUMBER OF TEXT PAGES: 146 



16. PRICE CODE 



17. SECURITY CLASSIFICATION OF 

 REPORT Unclassified 



18. SECURITY CLASSIFICATION 

 OF THIS PAGE 



19. SECURITY CLASSIFICATION 

 OF ABSTRACT 



20. LIMITATION OF 

 ABSTRACT 



