The board may enter into any obligation or contract with the United States for the construction, operation, and maintenance of the necessary works for the delivery and distribution of water therefrom under the provisions of the federal Reclamation Act, and all acts amendatory thereof or supplementary thereto, and the rules and regulations established thereunder; or the board may contract with the United States for a water supply under any Act of Congress providing for or permitting such contract, and in case contract be made with the United States as herein provided, bonds of the district may be deposited with the United States at ninety percent of their par value, to the amount to be paid by the district to the United States under any such contract, the interest on such bonds to be provided for by assessment and levy as in the case of other bonds of the district, and regularly paid to the United States to be applied as provided in such contract, and if bonds of the district are not so deposited it shall be the duty of the board of directors to include as part of any levy, assessment, or toll provided for in sections 46-134, 46-135, 46-152, and 46-1,137, an amount sufficient to meet each year all payments accruing under the terms of any such contract. If contract is made with the United States as in this section provided and bonds are not to be deposited with the United States in connection with such contract, bonds need not be issued, or, if required to raise funds in addition to the amount of such contract, shall be issued only in the amount needed in addition thereto.