1.0 INTRODUCTION 



From October 1993 to February 1994, the New Haven Harbor was dredged to 

 improve navigational access within the federal channel and operations efficiency at five area 

 marine terminals (Figure 1-1). As part of the Dredged Material Management Plan, 

 formulated by the New England Division (NED) of the US Army Corps of Engineers 

 (US ACE), the federal channel project sediments were sampled and subjected to a variety of 

 tests to determine their physical and chemical properties. The results of a standard 

 Ampelisca bioassay test indicated that the federal channel project material was not suitable for 

 unconfined open water disposal and required capping. Capping is a subaqueous containment 

 method which uses dredged material determined to be suitable for unconfined open water 

 disposal to overlay and isolate the unacceptably contaminated dredged material (UDM) from 

 the environment (Fredette 1994). The process was introduced to the Central Long Island 

 Sound Disposal Site (CLIS) in 1979 with the formation of the Stamford-New Haven mounds 

 (STNH-N and STNH-S; SAIC 1995). 



Subaqueous capping is the most cost effective and environmentally sound approach to 

 manage large volumes of UDM. Results of the Stamford-New Haven Project suggested that 

 careful navigational controls and point deposition techniques at a taut-wired buoy could be 

 used to form a discrete mound of UDM (SAIC 1995). In addition, these results suggested 

 that precise deposition of cap dredged material (CDM), both at the center and at the flanks of 

 the UDM mound, could be accomplished with tight navigational control and project 

 planning. As a result of the operational success of the 1979 capping project, additional 

 capping projects were conducted at CLIS. These include the Mill-Quinnipiac River mound 

 (MQR), Norwalk mound (NORWALK), and two Experimental Cap Sites (CS-1 and CS-2). 

 Physical monitoring of the mounds indicates that they have been stable even after the passage 

 of three hurricanes (SAIC 1995). 



A successful capping project requires an effective monitoring program in addition to 

 predisposal planning and well-organized dredging and disposal operations (SAIC 1995). 

 Science Applications International Corporation (SAIC) conducted a series of five 

 environmental surveys including the collection of various types of data at each stage of the 

 dredging project (Table 1-1). The data collected at CLIS includes precision bathymetry, 

 Remote Ecological Monitoring of the Seafloor (REMOTS®) sediment-profile photographs, 

 sediment grab samples, and geotechnical cores (Figure 1-2). The strategic repetition of 

 survey operations over the disposal site during the New Haven Capping Project provided 

 SAIC and NED a wealth of information on the developing mound. 



The baseline survey conducted from 19 to 20 September 1993 was intended to define 

 the predisposal conditions at the site to provide a baseline for comparison to the future survey 



Monitoring Surveys of the New Haven Capping Project, 1993-1994 



