Only one survey near the end of the flood tide was attempted on November 15 due to 

 deteriorating weather conditions (Figure 3-20). The barge was located to the west of Morris 

 Cove on the eastern edge of the navigation channel. Patches of the plume were observed in 

 the echo sounder record as far as 900 meters northeast of the barge, outside of the channel in 

 Morris Cove (Figures 3-21). The plume protruded onto the shoals a maximum distance of 

 700 meters from the east edge of Uie channel. The CTD profiles show minimal vertical 

 density stratification, indicating a homogenous water column. By the next day, November 

 16, the dredge had moved north about 300 meters, stUl along the eastern edge of the 

 navigation channel (Figure 3-22). One survey was completed just before maximum ebb. 

 Remnants of the plume were observed in Morris Cove, east of the channel, approximately 

 700 meters downstream of the barge (Figure 3-23). Plume traces were poorly defined and 

 difficult to interpret during this survey. The CTD data, collected along the axis of the 

 channel, show weak vertical and horizontal density gradients. 



The final survey took place on November 18; the dredge was initially positioned near 

 buoy "15" and proceeded slowly northward throughout the survey to a final position 

 approximately 60 meters from its origin (Figure 3-24). One survey during maximum flood 

 currents was conducted. The echo sounder record shows a patch of the plume in the channel 

 nearly 600 meters upstream of the dredge barge (Figures 3-25). Small patches were detected 

 outside of the channel, to the east and west, but generally only for short distances — within 

 1(X) meters. Plume definition throughout this survey was generally good. Again, the CTD 

 profiles were obtained along the axis of the channel and indicate weak vertical, as well as 

 horizontal, density gradients. 



3.2 Water Sampling 



During most of the plume surveys, water samples were collected to ascertain the 

 relative amounts of suspended sediment with distance from the dredging operations. The 

 results of this sampling are summarized in Table 3-2 and the location of each water sample 

 relative to the barge is shown in the Figures 3-6, B; 3-9, B; 3-10, B; 3-13, B; 3-15, B; 3-17, 

 B; 3-20, B; and 3-22, B. The highest concentration measured (662 mg-l'^ ) was located 

 within 100 meters of the barge and associated with the near bottom waters. Indeed, most of 

 the higher concentration data were within a 100 meter range of the barge, regardless of the 

 tide stage. Beyond that distance, most of the data indicates that the concentrations within the 

 dredge-induced plume were relatively low, decreasing rapidly under the combined effects of 

 settling, advection, and turbulent diffusion and mixing. 



3.3 DAISY Deployments 



The bottom-mounted instrument array (DAISY) collected data from October 25 to 

 December 7, 1993. The instruments on the array sampled conditions approximately one 



Dredged Sediment Dispersion in New Haven Harbor 



