Wyo. Stat. § 41-3-604
It shall be the duty of the said water commissioner to divide the water of the natural stream or streams of his district among the several ditches and reservoirs taking water therefrom, according to the prior right of each, respectively, in whole or in part, and to shut and fasten, or cause to be shut and fastened, the headgates of ditches and shall regulate or cause to be regulated the controlling works of reservoirs, in times of scarcity of water, as may be necessary by reason of the priorities of right existing from said streams of his district. Such water commissioner shall have authority to regulate the distribution of water among the various users under any partnership or incorporated ditch or any ditch owned by joint owners not incorporated and not in a partnership, or partnership or incorporated reservoir or reservoir owned by joint owners not incorporated or not included in a partnership, where rights have been adjudicated, in accordance with existing decrees. Whenever, in the pursuance of his duties, the water commissioner regulates a headgate to a ditch or the controlling works of reservoirs, it shall be his duty to attach to such headgate or controlling works a written notice, properly dated and signed, setting forth the fact that such headgate or controlling works has been properly regulated and is wholly under his control and such notice shall be a legal notice to all parties interested in the division and distribution of the water of such ditch or reservoir. It shall be the duty of the county attorney to appear and defend the division superintendent or any water commissioner who shall be made a defendant in any case which may arise in the pursuance of the official duties of any such officer within the county of such county attorney.
W.S. 41-3-604