Idaho Code § 67-4209

The park and recreation board of the department of parks and recreation, hereinafter referred to as the board, acting for and in behalf of the people of the state of Idaho, is hereby authorized to enter into any agreement with the United States or with any of its departments, bureaus, or other agencies, which agreement shall provide for the development and administration of recreational resources or facilities located or to be located, upon lands owned by the United States and which are adjacent to, or which resources or facilities may be used in connection with the waters of, those certain bodies of water known as Walcott Lake, located in Power, Cassia, Minidoka and Blaine Counties, American Falls Reservoir, located in Power, Bingham and Bannock Counties, and Cascade Reservoir, located in Valley County. Any such agreement shall expressly recognize that the authority to be assumed by the board shall be exercised with due and proper regard for the primary purposes and uses for which such lands and waters are operated and maintained by the United States or others, and with due regard for the right of ingress and egress over said lands for watering livestock in said lake and reservoir.