570 ALSTON, LAWRENCE, BAYNE, AND CAMPBELL 



variables, and controlled studies used extremely artificial in-vitro 

 experiments. Our study attempted to compromise the two extremes 

 by controlling the amount of flow and water temperature in earthen 

 channels. The channels were constructed in 1974 by the Alabama 

 Power Company to evaluate the environmental effects of heated 

 effluents on aquatic biota. The experiments were designed to gather 

 specific information to be used in an overall effort to determine the 

 environmental impact of heated water released from steam 

 electric-generating plants into Alabama streams and reservoirs. 

 Specifically, the investigative emphasis was on water quality, 

 production of fish-food organisms, and health, reproduction, and 

 growth of confined fishes. In this paper the only objectives 

 considered are determining the effects of heated water on fish-food, 

 organisms in earthen channels and investigating seasonal changes in 

 fish-food organisms which occur over a 2-year period (October 1974 

 through October 1976). 



MATERIALS AND METHODS 



Channels 



Three earthen channels, 6 by 160 m, with a maximum depth of 

 2 m (Fig. 1), were constructed in Greene County, Alabama, on the 

 site of the 500-MW Greene County Steam-Electric Generating Plant. 

 Water entered tne southern end of each channel to provide a 



CHANNELS 1 AND 3 



INTAKE 



I V 

 J 1 



AMBIENT INTAKE t— WARM INTAKE 



r— AlVIBItNl IIMIAMZ r— 



Vj . A 



AMBIENT WATER 



V X 



J , . L_ 



1 r° zz^ 1 1 r 



^ -^ WARM WATER 



CHANNEL 2 



Fig. 1 Longitudinal section of the channels. Roman numerals are 

 stations; warm water is the heated-water density current, and arrows 

 indicate direction of flow. 



