PUBLIC LAWS-CH. 418-AUG. 4, 1939 First annual install- ment, accrual date. Yearly installment of organization's re- payment obligation. Short- or long-term contracts to furnish water for irrigation purposes. Removal of sand, gravel, etc. Proviso. Removals without charge if for public use. (4) That the first annual installment for any project contract unit, or for any irrigation block, as the case may be, shall accrue, on the date fixed by the Secretary, in the year after the last year of the development period or, if there be no development period, in the calendar year after the Secretary announces that the construction contemplated in the repayment contract is sub- stantially completed or is advanced to a point where delivery of water can be made to substantially all of the lands in said unit or block to be irrigated; and if there be no development period fixed, that prior to and including the year in which the Secretary makes said announcement water shall be delivered only on the toll charge basis hereinbefore provided for develop- ment periods. (5) Either (A) that each year the installment of the organi- zation's repayment obligation scheduled for such year shall be the construction charges due and payable by the organization for such year; or (B) that each year the installment for such year of the organization's repayment obligation shall be increased or decreased on the basis of the normal and percentages plan provided in section 4 of this Act for modification of existing obligations to pay construction charges, and the amount of the annual installment of the organization's obligation, as thus increased or decreased, shall be the construction charges due and payable for such year. Under "(B)" of this subsection the pro- visions of section 4 of this Act shall be applicable, as near as may be, to the repayment contract made in connection with the new project, new division of a project or supplemental works on a project; and the organization shall make payments on the basis therein provided until its general repayment obligation has become due and payable to the United States in full. (e) In lieu of entering into a repayment contract pursuant to the provisions of subsection (d) of this section to cover that part of the cost of the construction of works connected with water supply and allocated to irrigation, the Secretary, in his discretion, may enter into either short- or long-term contracts to furnish water for irrigation purposes. Each such contract shall be for such period, not to exceed forty years, and at such rates as in the Secretary's judgment will produce revenues at least sufficient to cover an appropriate share of the annual oper- ation and maintenance cost and an appropriate share of such fixed charges as the Secretary deems proper, due consideration being given to that part of the cost of construction of works connected with water supply and allocated to irrigation; and shall require payment of said rates each year in advance of delivery of water for said year. In the event such contracts are made for furnishing water for irrigation purposes, the costs of any irrigation water distribution works constructed by the United States in connection with the new project, new division of a project, or supplemental works on a project, shall be cov- ered by a repayment contract entered into pursuant to said subsection (d). SEO. 10. The Secretary, in his discretion, may (a) permit the removal, from lands or interests in lands withdrawn or acquired and being administered under the Federal reclamation laws in connec- tion with the construction or operation and maintenance of any proj- ect, of sand, gravel, and other minerals and building materials with or without competitive bidding: Provided, That removals may be per- mitted without charge if for use by a public agency in the construc- tion of public roads or streets within any project or in its immediate [53 STAT.