Wyo. Stat. § 41-4-310
Whenever the state board of control shall, as provided by law, proceed to adjudicate and determine the rights of the various claimants to the use of water upon any stream or other body of water, it shall be the duty of all claimants interested in such stream or other body of water to appear and submit proof of their respective appropriations, at the time and in the manner required by law; and any such claimant who shall fail to appear in such proceedings and submit proof of his appropriations shall be barred and estopped from subsequently asserting any rights theretofore acquired upon the stream or other body of water embraced in such proceedings, and shall be held to have forfeited all rights to the use of said stream theretofore claimed by him. Provided, that any person claiming the right to the use of water of any stream heretofore adjudicated by the board of control who, having been or claiming to have been at the time an appropriator therefrom, shall have failed to appear and submit proof of his claim shall be permitted within one (1) year after the passage of this act, but not thereafter, to apply for a hearing and an adjudication of his rights in the manner hereinafter provided; and provided, further, that any claimant upon whom no other service shall be made than by publication in the newspaper, of the notice of such proceedings and taking of testimony, may, within one (1) year after the entry of the order or decree of the board, determining the rights of the various claimants upon any particular stream or other body of water, have the same opened and be let in to give proof of his appropriation; but before the decree of the board can be opened in such case, the applicant shall give notice to all other persons interested in the water of the stream or other body of water in question, and shall with his petition file the same kind of proof as required of claimants in original hearings and make it appear to the satisfaction of the board that during the pendency of the proceedings he had no actual notice thereof in time to appear and make proof of his claim; and all parties interested may present affidavits as to the matter of actual notice of the applicant.
W.S. 41-4-310