ARM 17.30.636. GENERAL OPERATION STANDARDS

(1) Owners and operators of water impoundments that cause conditions harmful to prescribed beneficial uses of state water shall demonstrate to the satisfaction of the department that continued operations will be done in the best practicable manner to minimize harmful effects. New water impoundments must be designed to provide temperature variations in discharging water that maintain or enhance the existing propagating fishery and associated aquatic life. As a guide, the following temperature variations are recommended: continuously less than 40ºF during the months of January and February, and continuously greater than 44ºF during the months of June through September.