; and (B) the local organization shall give reasonable assurances, and provide evidence, that such demands for the use of such storage will be made within a period of time which will permit repayment within the life of the reservoir structure of the cost of such storage. (2) Assurances The Secretary shall determine prior to initiation of construction or modification of any reservoir structure including water supply storage that there are adequate assurances by the local organization or by an agency of the State having authority to give such assurances, that— (A) the Secretary will be reimbursed the cost of water supply storage for anticipated future demands; and (B) the local organization will pay not less than 50 percent of the cost of storage for present water supply demands. (3) Repayment (A) In general The cost to be borne by the local organization for anticipated future demands may be repaid within the life of the reservoir structure but in no event to exceed 50 years after the reservoir structure is first used for the storage of water for anticipated future water supply demands, except that— (i) no reimbursement of the cost of such water supply storage for anticipated future demands need be made until such supply is first used