3-28 



Temperatuve Distribution for the Sample Year 



Temperature, in addition to salinity, plays an important role 

 in harbor hydrodynamics and in determining the distribution of biolo- 

 gical communities. 



In general, inner harbor stations have the highest tempera- 

 tures as well as the greatest tidal temperature variations. The mean 

 temperature for 17 stations over the sample year was 12.3 C, with a 

 minimum monthly mean of 1.3 C and a maximum of 26.6 C. Maximum values 

 were recorded in July and August. Thermal stratification, as well as 

 pronounced salinity stratification, was evident during April at nearly 

 all ebb-tidal survey stations. Little thermal variation with depth, 

 tide or station location was seen during other monthly surveys. Excep- 

 tions were at Station 2, near United Illuminating Company's English < 

 Station discharge, and at Station 8, near the New Haven Harbor Station. 

 At both of these locations, temperatures higher than ambient conditions 

 were occasionally observed. 



Data from the sample year (November 1976 through October 1977) 

 showed details of annual temperature variations in the Harbor (Figures 

 3-5, 3-7) . In November, Long Island Sound waters along the axis of the 

 main channel near the harbor mouth were isothermal (7.5 C) . Some 

 elevated temperatures (8.0 to 8.5 C) were observed in the middle of the 

 harbor during ebb tide, possibly corresponding to the Harbor Station 

 discharge plume. Near the head of the estuary, conditions were iso- 

 thermal and identical to those at the harbor mouth on both phases of the 

 tide (7.5 C). By December, temperatures had dropped sharply. Long 

 Island Sound waters and those of the outer harbor were generally iso- 

 thermal (at 3.5 C) , whereas near the head of the estuary temperatures 

 were somewhat lower (2.5 C) . At a few locations, the water column was 

 theimally stratified, with the coldest water at the surface. Due to the 

 severe cold weather, and attendant freezing, January data are incom- 

 plete. Ebb tide temperatures were 0.0 C and colder. 



