Mont. Code Ann. § 85-2-370

The department may adopt rules to implement the provisions of 75-5-410, 85-2-360 through 85-2-364, and 85-2-368. The rules must be oriented toward the protection of existing rights from adverse effects from net depletions caused by new appropriation rights or changes in appropriation rights in closed basins and must be consistent with and not exceed the requirements of 75-5-410, 85-2-360 through 85-2-364, and 85-2-368.