Oregon Revised Statutes Water Resources: Irrigation, Drainage, Flood Control, Reclamation § 545.389

(1) In fixing the proportionate part of the cost of the reclamation that each owner of land shall pay, the amount to be paid to any owner for easements, rights of way, water rights or other property or rights required by the district, may be deducted from the amount that the owner of the property or rights would otherwise be required to pay, and assessments for payment of the cost of the reclamation, and interest thereon, may be made accordingly. Property and rights so acquired shall not be vested in the district until bonds have been disposed of or means otherwise provided for reclamation of the land in the district.

(2) Before completion of the project, the board may adjust the assessment so that the lands to which the district delivered water or could on demand have delivered water, during the preceding irrigation season, shall, in addition to their pro rata share of the remainder of the assessment, pay for the operation and maintenance of the constructed or partially constructed works through which the lands receive water.