(a) Necessity
No water for irrigation may be delivered from the works of any project constructed under the authority of this subchapter until after the repayment contract or contracts required by this section have been executed. Where practicable in the judgment of the Secretary, the repayment contract shall be with a water users' organization or organizations satisfactory in form and powers to the Secretary; and otherwise the repayment contract shall be with the individual landowners. The contract or contracts shall contain such provisions as the Secretary deems necessary to carry out the purposes of this subchapter and to protect the interests of the United States.

(b) "Reimbursable construction costs" defined
The term "reimbursable construction costs" as used in this subchapter means that part of the costs of investigating, constructing, and operating and maintaining the project, which are allocated by the Secretary to irrigation, and which are met by expenditures of moneys therefor appropriated under the authority of section 590z–10(1) of this title, plus such amounts as the President, under section 590z(1) of this title, may determine to be reimbursable: Provided, That administrative expenses incurred in the District of Columbia in connection with the investigation construction, or operation and maintenance of a project shall not be included in the reimbursable construction costs nor shall they be charged to the water users in any way.

(c) Terms
The repayment contract or contracts for a project shall, in their aggregate, provide for repayment to the United States of the total amount of the reimbursable construction costs of the project allocated to irrigation. Each such contract shall provide, among other things, that—

(1) The Secretary shall fix a development period for each project of not to exceed ten years from and including the first calendar year in which water is delivered for the lands in said project; and during the development period water shall be delivered to the lands in the project involved at a charge per acre-foot, or other charge, to be fixed by the Secretary each year and to be paid in advance of delivery of water. Such charges shall be fixed with a view of returning such amounts as in the Secretary's judgment are justified by the rate of project development, including as a minimum the return over the full development period of that part of the cost of operating and maintaining the project, during said period, allocated by the Secretary to irrigation; and collections of such charges in excess of the cost of the operation and maintenance during the development period, as thereafter determined by the Secretary, shall be credited to the reimbursable construction costs of the project in the manner determined by the Secretary.

(2) The United States shall operate and maintain the project during the development period fixed for it. After the development period, the United States shall operate and maintain the project or any part thereof as long as is deemed necessary by the Secretary, and shall be paid in advance for each year that part of the estimated cost of operating and maintaining the project for such year allocated by the Secretary to irrigation. In the event charges due the United States are not paid when due the United States may, at its election, suspend operations in whole or in part.

(3) The repayment of the reimbursable construction costs, except as to Indian lands which shall be repayable in accordance with existing law relating to Indian lands, shall be spread in not to exceed forty annual installments, of the number and amounts fixed by the Secretary; and the first annual installment under each contract shall become due and payable on the date fixed by the Secretary, in the year next following the last year of the development period fixed under subsection (c)(1): Provided, That the provisions of this subsection shall not be construed to modify the provisions of special legislation pertaining to any particular project.

(4) The water users or their organization will take such measures as the Secretary deems proper to secure the adoption of proper accounting, to protect the condition of project works, and to provide for the proper use thereof, and to protect project lands against deterioration due to improper use of water. Delinquencies in any payments due to the United States shall be penalized by a penalty of not less than one-half of 1 per centum per month. No water shall be delivered to or for any land or party while either said land or the organization in which it is located or said party is in arrears in the advance payment of operation and maintenance charges or development period charges under subsection (c)(1), or in arrears for more than twelve months in the payment of an installment of the reimbursable construction costs.

(5) The Secretary shall establish the size of farm units of irrigable lands on each project in accordance with his findings of the area sufficient in size for the support of a family on the lands to be irrigated. No water may be delivered to or for more than the farm unit area of irrigable lands in the project owned by a single landowner: Provided, That this subsection shall not apply to the United States or any agency or instrumentality thereof, corporate or otherwise. No water shall be delivered to or for any land, in a project area, transferred or disposed of subsequent to approval of the project by the President, and within three years from the time water becomes available, unless and until it has been shown to the satisfaction of the Secretary or his duly authorized representative that the land has been transferred or disposed of at a price not exceeding the appraised value as determined by the Secretary or his duly authorized representatives, and upon proof of fraudulent representation as to the true consideration involved the Secretary is authorized to cancel the water right attaching to the land involved: Provided further, That nothing herein shall be construed to create authority to interfere with the delivery of water under prior rights.