Aquatic Ecosystems and Thermal Power Plants

The factors which affect biological responses to temperature changes in aquatic ecosystems are discussed in terms of their influence on siting, design and operation of thermal power plants. Recommended are: (1) the development of a basis for classifying aquatic organisms according to their relative importance in maintaining the balance of specific ecosystems; (2) the biological zoning of receiving waters, with time-dependent temperature criteria based on the annual reproduction cycles of ecologically important species; (4) the development of criteria which incorporate the effects of temperature rise, duration of exposure, rate of change, and frequency of violation; (4) the field investigation of planktonic entrainment in cooling water intakes to evaluate the effects of temperature, turbulence and recirculation; (5) a flexible approach to the design of cooling water systems so as to facilitate subsequent modifications and additions; and (6) the incorporation into plant operational procedures of careful control of rates of load change.