over the next two days, Saturday and Sunday. An additional contributing factor to this event 

 may have been the winds. Wind speeds during this time peaked at 10 m-s' out of the north 

 for several hours (Figure 3-32; B). The fetch is sufficient and the winds strong enough to 

 disturb the sediment- water interface at the water depths typical of this site. The wind, in 

 combination with the increase in total effluent and suspended solids load from the sewage 

 treatment facilities, appear to have been the principle factors producing this event. 



After November 21 suspended material concentrations decreased from the maxima, 

 although instantaneous values often exceeded 100 mg-l' resulting in average values 

 significantly above the pre-perturbation levels. Included in this portion of the record are 

 several short duration perturbations most probably caused by the inshore migration of 

 materials resuspended by dredging in progress within Reach 2. Again, the majority of the 

 perturbations during this period show characteristics different than those expected for dredge- 

 induced perturbations. This may be the result of a residual effect from the previous three- 

 day event, increasing the overall background concentrations. 



On November 29 another large amplitude perturbation was observed, persisting for 

 approximately 24 hours which does correlate with an increase in river discharge 3-5 times 

 larger than the average flow. The salinity record shows a decrease of nearly 6 units on the 

 practical salinity scale during the event (Figure 3-33; B). Records from the East Shore 

 Water Pollution Abatement Facility (WPAF) do not indicate that there was a substantial 

 contribution from this waste facility. However, there are 24 CSOs which discharge into 

 upper New Haven Harbor; four of the largest ones are located south of the Tomlinson Bridge 

 (Figure 1-1). Thus, although the data does not show significantly elevated effluent levels 

 from the East Shore Facility, there may be a considerable contribution from the CSOs to the 

 observed high concentrations. Potentially augmenting the increased river flow and CSO 

 discharges, winds during the previous two days averaged above 10 m-s '^ and reached 

 maximum speeds of 20 m-s' from the south. There is enough fetch to produce waves that 

 would resuspend sediments at 4 meters depth, which then would have settled as the winds 

 dropped and shifted to the north throughout the following day, possibly contributing to the 

 high concentrations recorded. There is a similar event which occurred during the latter part 

 of the day on November 30, again, possibly the result of stream flow 1.5 to 2 times higher 

 than average, increased CSO input, and northerly winds. 



The final and highest concentrations recorded during the entire deployment period 

 spanned two days— December 2 and 3. No major stream flow events were recorded during 

 this time. Winds were initially northerly but shifted to the east during the second day with 

 speeds less than 10 m-s'. There appears to be no significant contribution from the East 

 Shore WPAF effluent. Although a northerly wind seems to have induced elevated suspended 

 material concentrations in previous events, it is not likely that the winds produced the 

 observed increase during this two-day period. A 700 mg-l' perturbation, persisting for 



Dredged Sediment Dispersion in New Haven Harbor 



