Okla. Stat. tit. 82 § 668
All payments to become due to the United States under any federal contract entered into between a master conservancy district and the United States may be paid from revenues or derived from assessments upon the real property of the district, as provided in the Conservancy Act. It shall be the duty of the board of directors of a contracting district, pursuant to the provisions of the Conservancy Act, to make and establish all levies, assessments, tolls or charges to meet each year the contract indebtedness and obligation as the same may be provided for in any federal contract heretofore or hereafter entered into by a contracting district and to do any and all acts necessary to carry out the provisions of any such federal contract.
Okla. Stat. tit. 82, § 668