Description: Under Policy 5C of the Swan Falls Agreement of 1984 between the Idaho Power Company and the State of Idaho, certain hydropower water users are subordinated to other upstream beneficial water users. The flows at Swan Falls that are between the minimum flow of the swan falls agreement and the appropriated amount are held in trust by the state and may be subject ot depletion by future beneficial upstream users. This 'trust" water includes only those waters, inculding groundwater, from areas which are tributary to the Snake River above Milner and Swan Falls Dam. Rights to use water tributary to the Snake River above Milner Dam are not to be administered with rights to use water downstream from Milner Dam. Internal polygons represent perched aquifer areas that are not tributary to the Snake River (Milner to Swan Falls), yet the underlying regional aquifer is tributary to the Milner to Swan Falls reach of the Snake.