REPORT DOCUMENTATION PAGE 



Form approved 

 0MB No. 0704-0188 



Public reporting concern for the collection of information is estimated to average 1 hour per persons inculding the time for reviewin<J 

 instructions, searching existing data sources, gathering and measuring 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 includin<J suc^estions 

 for reducing this burden to Washington Headquarters Services, Directorate for Information Observations and Records, 1216 Jefferson 

 Davis Highway. Suite 1204, Arlington VA 22202-4302 and to the Office of Management and Support. 



1. AGENCY USE OMLY (LEAVE BLANK) 



2. REPORT DATE 



January 1999 



3. REPORT TYPE AND 

 DATES pj^^i j^gpgj^ 



4. TITLE AND SUBTITLE Monitoring results from the first Boston Harbor Navigation Improvement Project 

 confined aquatic disposal cell 



6. AUTHORS 



PEGGY MYRE MURRAY 



6. FUNDING NUMBERS 



7. PERFROMING ORGANIZATION NAME(S) AND ADDRESS(ES) 



Science Applications International Corporation 

 221 Third Street 

 Newport, RI 02840 



8. PERFORMING 

 ORGANIZATION REPORT 



SAIC No. 443 



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



US Army Corps of Engineers-New England District 

 696 Virginia Rd 

 Concord, MA 01742-2751 



10. SPONSORING/ 

 MONITORING AGENCY 



DAMOS Contribution 

 Number 124 



11. SUPPLEMENTARY NOTES 



Available from : DAMOS PROGRAM MANAGER Regulatory Division, USACE-NAE 

 696 Virginia Rd 



Connord MAni747-77Sl 



12a. DISTRIBUTION/A VAIABILTY STATEMENT 



Approved for public release; distribution unlimited 



12b. DISTRIBUTION CODE 



13. ABSTRACT 



As part of the overall Boston Harbor Navigation and Innprovement Project (BHNDP), shipping berths 1 1 and 12 

 at Conley Terminal in South Boston were deepened to -40 ft and -45 ft MLLW, respectively, in June- July 1997. In 

 phase! of the BHNIP, fine-grained maintenance sediment, classified as unsuitable for open-disposal, was dredged and 

 placed into an in-channel confined aquatic disposal (CAD) cell in Boston Harbor. The cell was extracted into the 

 existing federal channel, below the BHNIP channel depth of -40 ft MLLW. Following placement of maintenance 

 material into the cell, sufficient sand to cover the dredged material with a minimum of 3 ft capping layer was placed 

 using split-hull scows. 



A monitoring survey was conducted by SAIC in October 1997 to assess the status of capped CAD cell. Survey 

 methods included one day of vibracoring, and one day of acoustic surveying including bathymetry, subbottom, and 

 side-scan sonar. Results of the survey indicated that most of the CAD cell was covered with a highly variable 

 thickness of sand, while the southern end had little to no cap material. This distribution was consistent with the 

 positioning of the split-hull scows used to dispose the sand. Sand disposal was permitted during the outgoing 

 (southerly) tidal cycle. Prior to the initiation of the project, preliminary modeling of sand transport due to Boston 

 Harbor tidal currents predicted that sand would be transported to the south, so no barge was placed directly over the 

 southern end of the cell. The results suggested that the sand remained in the convective state during placement, so that 

 all the cap material was placed directly below each positioned barge. 



The monitoring results also suggested that postcap operations designed to level the sand served to enhance 

 mixing of the cap and underlying dredged material, and resulted in uneven sand coverage. A final videosled survey 

 was conducted by C.R. Environmental in December 1997. These data confirmed the presence of a thick layer of sand 

 covered with tunicates and other organisms in most of the cell, and the flat, fine-grained uncapped mud surface to the 

 south. Overall, the maintenance material was successfully placed in the cell, and capped with sand in all locations 

 where capping barges were located. The results of monitoring of Phase I provided guidance for operational and 

 monitoring modifications for Phase II of the BHNIP in 1998-99. 



14. SUBECT TERMS 



Boston Harbor, South Boston, capping, confined aquatic disposal (CAD), videosled survey 



17. SECURITY CLASSIFICATION OF REPORT 



UNCLASSIRED 



18. SECURITY CLASSIFICATION 

 OF THIS PAGE 



19. SECURITY CLASSIFICATION 

 OF ABSTRACT 



15.NUMBER OF PAGES 



16. PRICE CODE 



20.LIM1TATION OF 

 ABSTRACT 



