REPORT DOCUMENTATION PAGE 



form approved 



OMB No. 



0704-0188 



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 

 egarding this burden estimate or any other aspect of this collection of information including suggestions for reducing this burden to Washington 

 Headquarters Services, Directorate for mformation Observations and Records, 1215 Jefferson Davis Highway, Suite 1 204, Arlington V A 22202-4302 

 and to the Office of Management and Support, Paperwork Reduction Project (0704-0188), Washington, D.C. 20503. 



1. AGENCY USE ONLY (LEAVE BLANK) 



2. REPORT DATE 



May 1998 



3. REPORT TYPE AND DATES COVERED 



FINAL REPORT 



4. TITLE AND SUBTITLE 



MONITORING CRUISE AT THE CENTRAL LONG ISLAND SOUND DISPOSAL SITE, 

 JULY 1996 



6. AUTHOR(S) 



JOHN T. MORRIS 



5. FUNDING NUMBERS 



PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 



Science Applications International Corporation 

 221 Third Street 

 Newport, RI 02840 



8. PERFORMIGORGANIZATION 

 REPORT NUMBER 



SAIC No. 385 



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



US Army Corps of Engineers-New England District 



696 Virginia Rd 



Concord, MA 01742-2751 



10. SPONSORING/MONITORING 

 AGENCY REPORT NUMBER 



DAMOS Contribution #120 



11. SUPPLEMENTARY NOTES 



Available from DAMOS Program Manager, Regulatory District 

 USACE-NAE, 696 Virginia Rd, Concord MA 01742-275 1 



12a. DISTRIBUTION/AVAILABILITY STATEMENT 



Approved for public release; distribution unlimited 



12b. DISTRIBUTION CODE 



13. ABSTRACT 



A monitoring survey was conducted at ihe Central Long Island Sound Disposal Site (CLIS) from 10 to 15 July 1996 as pari of ttie Disposal Area Monitoring System 

 (DAMOS) Program. Field operations were concentrated over the new CLIS 1995 disposal mound, as well as the historic New Haven 1993 (NHAV 93), CLIS 1994 (CLIS 94). and 

 Mill-Quinnipiac River (MQR) mounds. The July 1996 field effort consisted of precision bathymetric and Remote Ecological Monitoring of the Seafloor (REMOTS*) surveys. 

 These surveying techniques were employed to monitor the development of CLIS 95. as well as the stability, consolidation rates, and benthic recolonization of CLIS 94. NHAV 93, 

 and MQR capped mounds 



The CLIS 95 mound is the newest bottom feature at the disposal site and is an example of a small, capped, dredged material disposal mound. An estimated barge volume 

 of 16,300 m' of unacceptably contaminated dredged material (UDM) was deposited buoy, forming a small mound. The UDM deposit was then completely covered with 50,100 m' 

 of capping dredged material (CDM). 



The results of the July 1996 field effort indicate the formation of a small, but distinct, bottom feanire on the CLIS seafloor. This sediment mound was found to be 3 75 

 m high at the apex and approximately 200 m in diameter. REMOTS* photographs documented deep Redox Potential Discontinuity (RPD) depths, mature benthic infaunal 

 populations, and high Organism-Sediment Index (OSI) values, indicating rapid recolonization of these sediments 



The CLIS 94 mound, developed during the 1994-95 disposal season, is also an example of a capped mound Approximately 129,000 m' of UDM and 161.000 m' of 

 CDM were placed to form an irregular-shaped, moderate-sized disposal mound. A 0.25 m to 0.5 m decrease in mound height was discovered at the mound apex, while smaller cells 

 of consolidation were detected over the broader southern region of the mound The five REMOTS* stations occupied over the center of CLIS 94 displayed some improvement 

 relative to the conditions found during the September 1995 survey. The NHAV 93 mound was developed during the 1993-94 disposal season as part of a large scale confined aquatic 

 disposal (CAD) project In 1993. approximately 590.000 m' of UDM dredged from the inner New Haven Harbor was deposited within the containment cell and capped to a 

 thickness of 0.5 m to 1.0 m by 569,000 m' of CDM. 



A total of eight bathymetric and five REMOTS* sediment-profile photography surveys have been conducted over Ihe NHAV 93 mound since September 1993. At 2.5 

 years after the completion of capping operations, the July 1996 survey has shown 25 m to 0.75 m of consolidation over the majority of the mound with little change in size or 

 shape. The results of the REMOTS* sediment-profile photography survey indicate the benthic community is continuing to recover as expected. 



The MQR mound is a historic bottom feature formed along the southern boundary of CLIS This capped sediment mound is actually composed of alternating layers of 

 UDM and CDM deposited during the 1981-82, 1982-83, and 1993-94 disposal seasons Approximately 65,000 m^ of additional CDM was deposited over the MQR mound during 

 the 1993-94 disposal season in response to anomalous REMOTS* sediment-profile photography results 



Depth difference calculations based on the July 1994 bathymetric data discovered small to moderate pockets of consolidation near the apex and southwestern flank of 

 MQR. This consolidation over the surface of the MQR mound is apparently the result of de-watering of the underlying silts and clays, related to the loading diat resulted from the 

 recent deposition of CDM 



Seasonal hypoxia (DO concentrations <3.0 mg 1') generally occurs within the western and central Long Island Sound regions in mid to late August. However, the onset 

 and severity of seasonal hypoxia are directly dependent on many other environmental factors (i.e., nutrient input, frequency of storms, rainfall, fresh water input, water temperature, 

 etc.). It appears that, by conducting benthic community assessment survey operations in early summer (mid-June to mid-July), before the development of hypoxia and the 

 deterioration of benthic conditions, a more realistic perspective on the condition of the benthic environment can be gained. 



14. SUBJECT TERMS Central Long Island Sound (CLIS) , Capping Dredged Material (CDM), 

 Unacceptably Contaminated Dredged Material (UDM), New Haven Habor 



15. NUMBER OF PAGE 65 



16. PRICE CODE 



17. SECURITY CLASSIFICATION OF 

 REPORT Unclassified 



18. SECURITY CLASSIFICATION 

 OF THIS PAGE 



19. SECURITY CLASSIFICATION 

 OF ABSTRACT 



20. LIMITATION OF 

 ABSTRACT 



