Oregon Revised Statutes Water Resources: Irrigation, Drainage, Flood Control, Reclamation § 547.465

Whenever lands located in a drainage district which, because of their low elevation, were not assessed benefits in accordance with ORS 547.225, are used for growing crops, the board of supervisors may levy an annual assessment against the lands or may impose a charge upon the owners of the lands for maintenance and operation. The assessment or charge shall not exceed 100 percent of the rate levied against assessed lands in the district, or imposed upon owners of land in the district, having the lowest elevation. The charges or assessments shall be collected in the same manner as other charges or assessments for maintenance and operation in drainage districts are collected.