3-57 



The pH measured during monthly sampling was generally within 

 the normal range for natural estuarine waters, and showed no consistent 

 spatial or temporal pattern but was most variable in the inner harbor, 

 especially near the river mouths. The average values compiled in 1977 

 were not substantially different from the average values compiled from 

 1971 through 1976. 



Water transparency measurements showed no marked trends . In 

 general, extinction depths were similar over the seven years studied. 

 Inner harbor waters were generally slightly less transparent than outer 

 harbor or Long Island Sound waters. 



ANALYSIS OF IMPACTS 



The New Haven Harbor Station affects the hydrography of the 

 harbor by its intake of water at one location and its subsequent dis- 

 charge several hundred meters away. The water that passes through the 

 plant is mixed and heated between intake and discharge. Possible 

 impacts of this system relative to the physical/chemical or hydrographic 

 factors of the harbor include : 



1. Modification of local current and wave patterns 



2. Modification of the thermal regime in the harbor. 



3. Changes in dissolved oxygen concentration. 



4. Increased turbidity. 



Evidence for the occurrence of these impacts and evaluation of 

 their extent is presented below. 



