The board of directors of any irrigation or drainage district, organized under the laws of the state of Colorado, in its discretion, whenever it is determined by such board to be for the best interests of any such district, may contract with the United States or any governmental agency thereof to fund or refund any or all of the outstanding indebtedness of such district together with the interest accrued and unpaid thereon.L. 35: p. 677, § 1. CSA: C. 90, § 529. CRS 53: § 149-3-51. C.R.S. 1963: § 150-3-51.