(1) The provisions of this subchapter apply to any activity of man resulting in a new or increased source which may cause degradation.

(2) Department review of proposals for new or increased sources will determine the level of protection required for the impacted water as follows:

(a) For all state waters, existing and anticipated uses and the water quality necessary to protect those uses must be maintained and protected.

(b) For high quality waters, degradation may be allowed only according to the procedures in ARM 17.30.708. These rules apply to any activity that may cause degradation of high quality waters, for any parameter, unless the changes in existing water quality resulting from the activity are determined to be nonsignificant under ARM 17.30.670, 17.30.715, or 17.30.716. If degradation of high quality waters is allowed, the department will assure that within the United States Geological Survey hydrologic unit upstream of the proposed activity, there shall be achieved the highest statutory and regulatory requirements for all point and nonpoint sources. This assurance will be achieved through ongoing administration by the department of mandatory programs for control of point and nonpoint discharges.

(c) For outstanding resource waters, no degradation is allowed and no permanent change in the quality of outstanding resource waters resulting from a new or increased point source discharge is allowed.

(3) The department will comply with the provisions of the Montana Environmental Policy Act in the implementation of this subchapter.