1994, is 6 m^-s"*. For comparison, the annual mean flow from the Connecticut River, the 

 largest freshwater source to Lx)ng Island Sound, is 500 m^-s"' (from 1928 to 1994). Natural 

 depths within the harbor rarely exceed 4 meters. The navigation channel is flanked by broad 

 shallows, most notably Shag Bank on the western side with a mean depth of 0.5 meters. 

 Morris Cove, a large shallow embayment at the southeastern limit of the harbor, has a mean 

 depth of approximately 3 meters, except for an abandoned borrow pit located near the middle 

 of the cove, with a maximum depth of 1 1 meters. 



2.0 METHODS AND PROCEDURES 



2.1 Field Surveys and Water Sampling 



A Raytheon Model DE719C® 200 kHz echo sounder was used for detecting the lateral 

 and longitudinal extent of the suspended sediment plume. Transects were run cross-channel 

 in an east- west orientation, with usually one transect up current of the dredge as a control, 

 followed by several transects down current. A 1.7 liter Niskin bottle was used to collect 

 water samples. On recovery, all water samples were stored in prerinsed plastic jars and 

 returned to the laboratory for analysis. Concentrations of suspended sediment were 

 determined by vacuum filtration through dried and preweighed Nucleopore® membrane filters 

 (47 mm diameter, 0.40 micron pore size) mounted in standard Millipore* filtering apparatus. 

 Navigation data were acquired using a Magnavox MX200® GPS Navigator with an MX-50R® 

 Differential GPS Beacon Receiver attached to a notebook computer for continuous recording 

 of ship position along each of the transect lines. A Seabird Electronics SBE-19 Seacat 

 conductivity, temperature, and depth (CTD) probe was employed for obtaining hydrographic 

 data, whenever possible during a survey, to assess the vertical structure of the water column. 



2.2 DAISY Deployments 



Concurrent with the above field operations, a single bottom-mounted instrument 

 array, DAISY (Disposal Area In situ SYstem), was deployed to provide time series 

 observations of hydrographic conditions and suspended material concentrations at a single 

 point. The array was located immediately adjacent to the western edge of the navigational 

 channel, along the eastern boundary of the winter flounder spawning area (Figure 1-1). 

 Instruments mounted on the array included a single two-axis electromagnetic current meter, 

 temperature and conductivity probes, two optical sensors to detail suspended material 

 concentrations, and a datalogger for storing the data. The optical sensors were calibrated in 

 the laboratory prior to deployment using sediments obtained from New Haven Harbor. All 

 instruments were positioned to sample conditions at a point approximately 1 meter above the 

 sediment-water interface. The logger was programmed to burst sample at a rate :f 0.5 Hz 

 for a period of one minute, average the burst, and store data, four times each hour. Data 

 were recorded in digital binary format, stored in RAM, and downloaded during servicing to 



Dredged Sediment Dispersion in New Haven Harbor 



