Oregon Revised Statutes Water Resources: Irrigation, Drainage, Flood Control, Reclamation § 553.340

(1) The board, with such assistance as it deems necessary, shall prepare a benefit roll and determine the benefits that will accrue to each tract of land located within a subdistrict upon the construction of the works described in the engineering plan for the subdistrict. After such determination is made each landowner shall be given written notice thereof by registered mail or by certified mail with return receipt. If the landowner does not file written objections thereto within 30 days of the date the notice is mailed, the landowner shall be deemed to have consented to the allocation of benefits to the lands of the landowner. If a landowner files objections within 30 days, the determination of the benefits that will accrue to the lands of the landowner shall be referred to a board of appraisers. A board of three appraisers shall be appointed by the court, upon the petition of the board of directors, whenever one or more landowners within the subdistrict files an objection. Each of the appraisers shall, before assuming duties, take and subscribe to an oath that the appraiser will faithfully and impartially discharge duties as an appraiser and will make a true report of all work done by the appraiser. The court may, by order, remove any appraiser at any time and shall fill all vacancies on the board of appraisers or may appoint a new board as the case may require. The appraisers shall receive such compensation as the board of directors, with the approval of the court, determines, and shall be reimbursed for the expenses they incur in the exercise of their duties.

(2) Subsection (1) of this section shall not apply if the benefits to be determined are set forth in an irrigation project contract which has been executed by the owner pursuant to ORS 553.760.