3-15 



General circulation patterns in New Haven Harbor have been 

 documented by Duxbury (1963) . His composite chart for flood-tidal 

 currents (Figure 3-4) shows an indraft from Long Island Sound at speeds 

 varying from 22 to 45 cm/sec flowing northward along the channel axis 

 and upward into the Quinnipiac at 27 cm/sec. Apparently the flow into 

 Morris Cove is not as strong during the flood as during the ebb, sug- 

 gesting that residual inner harbor waters from the preceding ebb tide 

 are not entirely displaced by the flood. During the ebbing tide, a 

 small eddy forms between Long Wharf and the West River channel, causing 

 a localized trapping of water and a consequent decrease in flushing rate 

 (Figure 3-4) . The velocity shear between this eddy and the flow out of 

 the main channel creates a line of floating debris (personal obser- 

 vation) . Also, there is a tendency for the ebb to flow into Morris Cove 

 at a relatively high rate near shore (27 cm/sec) causing debris from the 

 inner harbor to be carried close to the shore at both Fort Hale and 

 Lighthouse Points. Flow observations at the mouth of the Mill and 

 Quinnipiac Rivers show ebb trapping of Mill River effluent along the 

 western bank and eventual contribution to the eddy off Long Wharf. On 

 the flooding tide, water from the inner harbor is carried upstream into 

 both rivers. 



Data collected by NOAA-NOS at the harbor entrance show a mean 

 maximum current velocity of 21 cm/sec on flood tide and 31 cm/sec on 

 the ebb. At the Tomlinson Bridge, mean peak tidal current velocity is 

 21 cm/sec on flood and 26 cm/sec on ebb. Tidal flow rates vary accord- 

 ing to the stage of the tide but average about 2500 m /sec over an 

 entire 12.4-hr tidal cycle. Ebbing tidal currents are stronger than 

 those on flood (Duxbury, 1963) due to the net seaward transport of 

 freshwater runoff. Stronger currents are generally restricted to the 

 main harbor channel, except for fairly strong (37 to 67 cm/sec) currents 

 to the south of Morris Cove and directly off Lighthouse Point during ebb 

 tide. In the main channel inside the breakwaters, the average current 

 is only 21 cm/sec. 



