For more information, see CCREM 1987

Thermal Stratification: Thermal additions to receiving waters should be such that thermal stratification and subsequent turnover dates are not altered from those existing prior to the addition of heat from artificial origins

Maximum Weekly Average Temperature: Thermal additions to receiving waters should be such that the maximum weekly average temperature is not exceeded

Short-term Exposure to Extreme Temperature: Thermal additions to receiving waters should be such that the short-term exposures to maximum temperatures are not exceeded. Exposures should not be so lengthy or frequent as to adversely affect the important species.

Human activities should not cause changes in ambient temperature of marine and estuarine water to exceed ±1°C at any time, location, or depth.  The natural temperature cycle characteristic of the site should not be altered in amplitude of frequency by human activities. The maximum rate of any human-induced temperature change should not exceed 0.5 °C per hour. 

Note:
Interim guideline.