Oregon Revised Statutes Water Resources: Irrigation, Drainage, Flood Control, Reclamation § 553.070

If any contract has been entered into between the district and the United States or the State of Oregon or any agency of either of them, or if the district has contracted to purchase any existing works and the purchase price has not been paid in full, no change shall be made in the boundaries of the district without the written consent of such contracting agency or the vendor of such existing works.