A decision tree framework was used to integrate engineering decisions concerned with the control of environmental impacts from stationary thermal power plants. The engineering costs and the ecological response of fish communities to any sequence of decisions in the tree can be computed with the models developed in this study. A series of formulations were also developed to describe the environmental impact of siting a series of power plants in a region. Both the static and dynamic models require verification before they are applied. Impacts of thermal and chemical discharges to the receiving waters and mechanical damage from screening devices are modeled.