ORS § 261.330
Any filing made by any people's utility district upon the unappropriated waters of this state for use in the future development of a hydroelectric plant by the district shall be reserved to the district and shall not be subject to appropriation by any other person, city or corporation, unless it is judicially determined that such filing exceeds the reasonable present and future requirements of the district, in which event the surplus or excess may be by judgment of a court of competent jurisdiction released and discharged from such filing. Proceedings in court for the determination of whether or not the filing by any utility district exceeds its reasonable present and future requirements may be instituted by the State of Oregon, by the Water Resources Commission in the name of and for the State of Oregon, or by any other applicant for the right to the use of the waters involved.
ORS 261.330