Oregon Revised Statutes Water Resources: Irrigation, Drainage, Flood Control, Reclamation § 540.310

(1) The owner of any ditch or canal shall maintain to the satisfaction of the Water Resources Commission a substantial headgate at the point where the water is diverted. It shall be of such construction that it can be locked and kept closed by the watermaster.

(2) The owner shall construct and maintain, when required by the commission, suitable measuring devices at such points along the ditch as may be necessary to assist the watermaster in determining the amount of water that is to be diverted into the ditch from the stream, or taken from it by the various users.

(3) When necessary for the protection of other water users, the commission may require flumes to be installed along the line of any ditch.