PREFACE 



As one who had a hand on the throttle of the Connecticut River 

 Ecological Study (Merriman and Thorpe, 1976) , it has been a privilege 

 for me to examine this work on New Haven Harbor. 



Both studies have dealt with the same problem: namely, the effects 

 on the aquatic ecosystem of the operation of a once-through condenser- 

 cooling complex as employed by an electricity-generating station. These 

 effects may be of two sorts: first, those resulting from the impact of 

 the thermal effluent emanating from the plant; and second, those 

 involving either the impingement of fish and other organisms on the 

 intake screen or the entrainment of the smaller elements of the biota 

 that are sucked through the screen and pass through the system. 



For the purpose of discussion here, it matters not at all that one 

 power plant, Connecticut Yankee (CY) , is nuclear while the other. New 

 Haven Harbor Station (NHHS) , is oil-fired. Fundamentally, we are con- 

 cerned with thermal and associated effects - i.e., what are the impacts, 

 potential or real, on the assemblage of plants and animals in the 

 affected area? 



Apart from the basic nature of the problem, the two studies have 

 certain other features in common. As the cros flies, the plants are 

 only 25 miles apart, so that in general they are subject to much the 

 same meteorological and seasonal vicissitudes . Both discharge their 

 waste heat into relatively large, though partially circumscribed , areas 

 of water that are characterized by a substantial amount of movement. 

 The one (CY) discharges its water at a rate of some 825 cubic feet per 

 second approximately 20° Fahrenheit warmer than when it was withdrawn 

 from the river 90 seconds earlier; the other (NHHS) operates its cooling 

 system at a rate of 625 cfs with a temperature increase of 15°F. 



At this point the gross features of the two studies become sharply 

 divergent. The one is essentially a riverine situation where, though 

 subject to major tidal effects, there is no salinity and the down-stream 

 flow of fresh water is predominant. This contrasts with the present 

 study that deals with an estuarine zone in which the saline waters of 

 Long Island Sound prevail over the relatively small runoff from several 

 rivers and in which the tidal flow is by far the most influential. As a 

 result, not only are the hydrographic conditions vastly different but 

 the flora and fauna, with only minor overlap, are wholly distinct from 

 those of the Connecticut Yankee situation. It is precisely these sorts 

 of differences that led Bell (1971) and others to point out the fallacy 

 in making universal regulations governing thermal discharges without 

 regard for the conditions peculiar to each plant site. Furthermore, 

 the methods of discharge of the heated effluent from the two plants are 

 radically different so that the respective impacts of each body of 



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