One of the environmental aspects of steam electric plants that is now receiving considerable attention is thermal effects — a term describing the impact that heated water from power plants can have on rivers, lakes, es­tuaries, or other bodies of water. Perhaps because today’s nuclear plants have to dispose of somewhat more heat to the environment than modem fossil fuel plants of the same generating capacity, there is a tendency to associate thermal effects with nuclear plants only. This is an erroneous impression, however, since both types of plants must reject sizable por­tions of the heat they produce to the environment.

Contrary to many statements which have been made, thermal effects are not necessarily bad in all situations. The effects may be detrimental, beneficial, or insignificant, depending on many factors — such as the man­ner in which the heated water is returned to the source water, the amount of source water available, the ecology of the source water, and its desired use. Certainly, warm water should not be considered a pollutant in the same sense as industrial wastes and municipal sewage.

The method of disposing of the heat rejected by the power plant will depend on both economic and environmental factors. In some situations, cooling methods other than the usual once-through method may be em­ployed in disposing of the waste heat. Artificial ponds can be constructed to provide a source of cooling water for continuous recirculation through the plant. Cooling towers can be used in other instances. Combinations of cooling methods can also be used effectively in many situations. For example, Virginia Electric and Power Company plans to use a manmade cooling lake of some 15 square miles at its North Anna Nuclear Power Station. The lake is expected to be a prime recreational area. This plan has been well received and approved by the Commonwealth of Virginia Water Control Board.

Although we have no legal authority to regulate utilities with respect to thermal effects, we do take positive measures to help control them. We have a cooperative agreement with the Department of Interior under which the Department reviews each application to build a nuclear power plant. Its recommendations on thermal effects are sent to the applicant, and we urge the applicant to cooperate with appropriate state and federal agencies. We have also testified in support of legislation now before Con­gress which would provide for the state certification to the aec of utility compliance with state water quality standards.