2011 ORS § 540.210¹
Distribution from ditch or reservoir

(1) Whenever any water users from any ditch or reservoir, either among themselves or with the owner thereof, are unable to agree relative to the distribution or division of water through or from the ditch or reservoir, either the owner or any such water user may apply to the watermaster of the district in which the ditch or reservoir is located, by written notice, setting forth such facts, and asking the watermaster to take charge of the ditch or reservoir for the purpose of making a just division or distribution of water from it to the parties entitled to the use thereof.

(2) The watermaster shall then take exclusive charge of the ditch or reservoir, for the purpose of dividing or distributing the water therefrom in accordance with the respective and relative rights of the various users of water from the ditch or reservoir, and shall continue the work until the necessity therefor shall cease to exist.

(3) The distribution and division of water shall be made according to the relative and respective rights of the various users from the ditch or reservoir, as determined by the Water Resources Director, by decree of the circuit court, or by written contract between all of the users filed with the watermaster.

(4) The circuit court having jurisdiction may request the watermaster of the district to take charge of any such ditch or reservoir, and to enforce any decree respecting such ditch or reservoir made under the jurisdiction of the court.