Basic concepts of waste heat management on shallow and deep small water bodies and rivers are reviewed and examples are given. This study defines a small water body as a body in which the far field hydrothermal effects of a heated discharge can be detected in a major portion or practically all of the water body. Environmental effects due to warming of a small natural water body are consequently not limited to the immediate area of the outfall. The report divides small water bodies into three categories: rivers, nonstratified water bodies, and stratified water bodies. Management and control alternatives for each category are discussed, as well as the biological effects of various cooling systems, and methods for prediction and thermal modelling. Emphasis is placed on the significance of site-specific variations and the necessity for consideration of all alternatives before selection of a cooling system for a particular site.