The report is a summary of 11 papers published in 15 different journals covering the following topics in water quality hydrology with special reference to water temperature: surface water freezing, quality of irrigation return flows, surface water temperatures, effects of temperature on rate of BOD exertion and ultimate BOD exerted, effect of impoundment on water quality, economics of thermal pollution control, minimum cost design and operation of water cooling towers, surface water heat balance, and spray pond evaporation and water cooling. Results of this work show that the beginning and ending dates of surface water freezing in lakes and streams can be accurately predicted from previous records. Also, the overturning of lakes depends on the minimum surface water temperature experienced on an annual basis (some shallow lakes are not temperature stratified). Both the rate of exertion and the ultimate BOD exerted increase with temperature up to about 38 deg C. While evaporation reduction is needed in the Western U.S. to improve water quality, the resulting temperature increase may be a serious problem. The cost of preventing thermal pollution would probably increase the price of electricity about 1 percent. (Author)