Oregon Revised Statutes Water Resources: Irrigation, Drainage, Flood Control, Reclamation § 540.340

(1) Whenever it may be necessary for the protection of other water users, the Water Resources Commission shall require every owner or manager of a reservoir or diversion dam, located across or upon the bed of a natural stream, to construct and maintain a suitable outlet in the reservoir or diversion dam which will allow the free passage of the natural flow of the stream. The commission shall determine what constitutes a suitable outlet.

(2) If any owner or manager of a reservoir or diversion dam refuses or neglects to construct or put in such outlet in the reservoir or diversion dam after 10 days' notice by the commission, the commission may close the ditch carrying water from the reservoir or diversion dam and it shall not be opened or any water diverted from the reservoir or diversion dam, under the penalties prescribed by law for the opening of headgates lawfully closed, until the requirements of the commission regarding such outlet have been complied with.