When a decree has been entered, any claimant who has failed to appear and submit proof of his claim as provided in this chapter shall be barred and estopped from subsequently asserting any rights theretofore acquired upon the stream system embraced in the proceedings, and shall be held to have forfeited all rights to water theretofore claimed by him on the stream system, other than as provided in the decree, unless entitled to relief under the laws of this State.