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4. TTTLE AND SUBTITLE 



THE PORTLAND DISPOSAL SITE CAPPING DEMONSTRATION PROJECT 1995-1997 



6. AUTHOR(S) 



JOHN T. MORRIS , HEATHER L. SAFFERT AND PEGGY MYRE MURRAY 



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



Science Applications International Corporation 

 221 Thrid Street 

 Newport, RI 02840 



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



US Army Corps of Engineers-New England District 

 696Virginia Rd 

 Concord, MA 01742-2751 



form approved 



0MB No. 



0704-0188 



1. AGENCY USE ONLY (LEAVE BLANK) 



2. REPORT DATE 



September 1998 



3. REPORT TYPE AND DATES COVERED 



FINAL REPORT 



5. FUNDING NUMBERS 



8. PERFORMIGORGANIZATION 

 REPORT NUMBER 



SAlC-402 



10. SPONSORIN(;/M()M'l OKINC. 

 AGENCY REPORT NUMBER 



DAMOS Contribution No. 12." 



11. SUPPLEMENTARY NOTES 



Available from DAMOS Program Manager, Regulatory Division 

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



12a. DISTRIBUTION/AVAILABILITY STATEMENT 



Approved for public release; distribution unlimited 



12b. DISTRIBUTION CODE 



13. ABSTRACT 



Sediments from the Royal River in Maine, considered suitable for open-ocean disposal, were sequentially dredged and disposed at the Portland Disposal Site (PDS) as a 

 proof-of-concept that dredged material could be placed, and capped, in a deep water open-ocean disposal site. Monitoring protocols developed through the Disposal Area 

 Monitoring (DAMOS) Program were utilized, as well as a newly developed tracer technique to track different lithologies of dredged material on the seafloor. Overall, the Portland 

 Disposal Site Capping Demonstration Project showed that dredged material can be effectively placed, capped, and monitored at a deep water disposal site. 



Disposal and capping of dredged material is a management technique for the containment of sediments considered unsuitable for open-ocean disposal (unaccepiably 

 contaminated dredged material, or UDM) that has proven successful in Long Island Sound, in relatively shallow water (approximately 20 m) and over a flat seafloor. Capping at 

 deep water disposal sites ( >40 m) was an unproven management method due to a variety of factors, including historical difficulties in disposal barge positioning, and shortage of 

 evidence confirming the formation of distinct UDM and capping layers. This tighdy controlled, closely monitored deep-water capping project has provided evidence diat the 

 technique can be successful in deeper waters. 



In order to avoid any potential adverse environmental impact from such a demonstration, material dredged from the Royal River. Yarmouth, ME, deemed suitable for 

 unconfined open-water disposal, was used as both "pseudo-UDM" as well as capping dredged material (CDM). Finer grained sediment removed from the upper reaches of the river 

 were designated as pseudo-UDM. Material from the lower reaches of the river, characterized by coarser grained material, was designated as the project CDM and was placed over 

 the initial pseudo-UDM deposit as a cap. The capped disposal mound was formed within a basin feature on the PDS seafloor at a depth of 64 m. After the completion ot disposal 

 and capping operations, the newly formed mound was surveyed and cored to confum the existence of two distinct layers. 



An important component of the Portland Disposal Site Capping Demonstration Project was the identification of tracers within the Royal River that could be used to 

 identify the sediment on the seafloor at the PDS. Prior to the excavation of sediment, 30 vibracores from three reaches (upper, middle, and outer) of the Royal River were collected 

 and analyzed for a variety of potential tracers. Although no single tracer was identified that was both unique to one reach of the river and commonly observed in all collected 

 samples, a statistical method of combining several biological and mineralogical parameters was found to be suitable for classifying the material types. 



Monitoring at the Royal River Project Area in the soudieast comer of die PDS utilized standard DAMOS techniques, including single-beam bathymetry, side-scan sonar. 

 REMOTS* sediment-profile images, as well as grab and core sampling. Results of the monitoring surveys showed that a discrete dredged material mound was detected on the 

 seafloor within the Royal River Project Area. An accumulation of pseudo-UDM was detected to the south and southeast of die disposal buoy position, located in die relatively tlat- 

 bonomed basin targeted for disposal. Sediment-profile images and core data were key to mapping the footprint of bodi UDM and CDM on die seafloor. 



The grab and core samples collected from the disposed dredged material were analyzed for die environmental tracers selected after analysis of Royal River Cores. The 

 statistical tracer data were able to show a discernible difference between the CDM, pseudo-UDM, and ambient material. 



The results of the demonstration project provided recommendauons for fiimre cap monitoring projects in deep water disposal sites, including suggestions for 

 modifications to both the monitoring protocols and to dredging and disposal operations. For areas of complex bottom topography, a higher resolution single-beam bathymetric 

 survey grid (5 to 10-m lane spacing) or multibeam bathymetry is required to provide more precise depth information over a wider area of seafloor. 



Finally, the tracer technique that was selected demonstrated promising results in tracking dredged material at a subaqueous disposal site. Several recommendations were 

 made to improve the mediod, including selecting tracers with the narrowest range in the dredging area, and sampling and analyzing the baseline (ambient and historical dredged) 

 material prior to disposal of project material. 



14. SUBJECT TERMS 



Royal River, Portland Disposal Site (PDS), capping, unacceptably contaminated dredged 

 material(UDM), dredging and disposal operations 



15. NUMBER OF PAGE 1 97 



16. PRICE CODE 



17. SECURITY CLASSIFICATION OF 

 REPORT Unclassified 



18. SECURITY CLASSIFICATION 

 OF THIS PAGE 



19. SECURITY CLASSIFICATION 

 OF ABSTRACT 



20. LIMITATION OF 

 ABSTRACT 



