Some problems in finding good standards for cooling water

Summary

Summarizing it can be said that whereas an increase in cooling water quantities to lower the presently used discharge temperatures had no positive effects, it certainly has marked negative effects especially on young fish. A decrease in the cooling water quantity on the other hand reduces damage to young fish, while serious damage to other organisms need not be feared. Even when discharge temperatures in excess of 30 °C would prove to be unacceptable, damage to young fish can be reduced by keeping the temperature jump of the cooling water as high as possible and consequently the quantity of cooling water as small as possible, taking due care that the maximum permissible discharge temperature is not exeeded.