The overall research objective was to evaluate the influence of heated water effluent on the limnology, fishery biology and community ecology of the receiving reservoir. A secondary issue was the surveillance of acid mine drainage into the reservoir. The study was also designed as a contribution to the limited knowledge of the ecology of cooling reservoirs. Acid water caused low mortality of fishes only at the point of inflow. Acid water of high specific gravity could be traced within the lake by sulfate levels and conductance until diluted. Thermal stratification occurred in the reservoir, but was transitory. Growth rates of young-of-the gizzard shad were not influenced by the heated water. Gizzard shad and largemouth bass concentrated in the heated water during winter and maintained a winter fishery. The heated water affected gonadal development and accelerated the time of spawning of largemouth bass. There was no difference between rates of accrual of Aufwuchs in heated and unheated water in the reservoir. (Author)