Oregon Revised Statutes Water Resources: Irrigation, Drainage, Flood Control, Reclamation § 547.555

(1) The board of supervisors may, if in its judgment it seems best, and subject to the approval of the electors of the district, issue bonds of the district for any purpose necessary or convenient to carry out the provisions of the Drainage District Act, including refunding of outstanding bonds, in denominations of not less than $100, bearing interest from date at a rate determined by the board, payable semiannually, to mature at annual intervals within 40 years, commencing after a period of years not later than five years, to be determined by the board of supervisors, both principal and interest being payable at some convenient insured institution or trust company, as those terms are defined in ORS 706.008, that is named in the bonds. Principal and interest, including principal, interest and premium payments made to redeem bonds under ORS 547.580, may be payable at the office of the treasurer of the district.

(2) The bonds shall be signed by the president of the board, attested with the seal of the district and by the signature of the secretary of the board. They may be issued so as to mature serially in annual amounts so as to be approximately equal, principal and interest, and may be issued so as to include a sum sufficient to pay the first four years' interest, or less, to accrue on the bonds.