ORS 551.060

After the petition has been granted and the proceedings had as specified in ORS 551.050, the court shall apportion the estimated cost of the dikes and dams among the landowners of the proposed district, in proportion to the valuation of the lands therein, according to the estimated value placed upon the respective tracts by the viewers. The cost thus apportioned shall be a tax upon the land and shall be placed upon the assessment roll of the county for the current year. Such taxes for diking purposes shall have the same legal effect and be collected in a like manner as other state and county taxes upon the assessment roll.