ORS § 545.131
An irrigation district may be merged and included within another irrigation district. The board of directors seeking merger shall present a petition showing the indebtedness of the district and its boundaries to the board of directors of the district in which it is desired to be included. The petition may be accepted or rejected by the latter board. If accepted, an election shall be ordered by the latter board in the district desiring to be included. At the election, the questions "Merger -Yes," and "Merger -No," shall be submitted to the qualified electors of the district and shall be determined by a majority vote of the qualified electors. The election shall be conducted in the same manner as an election for the organization of an irrigation district, and the board shall have the same powers and authority in conducting the election as are possessed by the county court in organizing an irrigation district. If the vote is "Merger-Yes," the indebtedness of each district shall be determined and entered upon the records. A division of the indebtedness shall be ordered which shall be binding on the districts. Thereafter the districts shall be one district with the lands of the merged district included in the surviving district to the same extent and effect in all respects as if originally included.
ORS 545.131