ORS § 545.335
When it appears necessary, proper or beneficial to drain any of the lands within the district, either for the benefit of the lands actually requiring drainage or for the protection of other lands within the district, and without regard to whether or not the irrigation works have been actually acquired or constructed, an irrigation district may cause drainage canals and works to be constructed. When exercising the authority granted by this section relating to drainage, the district shall have the same power and authority as is conferred on the district with regard to irrigation. All powers in the Irrigation District Law conferred upon irrigation districts with respect to irrigation shall be construed to include drainage. However, any bonds issued solely for drainage purposes shall be known as "Drainage Bonds of _____ Irrigation District."
ORS 545.335