; and (ii) no interest shall be charged on the cost of such water supply storage for anticipated future demands until such supply is first used, but in no case shall the interest-free period exceed 10 years. (B) Interest rate The interest rate used for purposes of computing the interest on the unpaid balance under subparagraph (A)(ii) shall be determined in accordance with section 12. (d) Condition of funds Nothing in this Act shall be construed to supersede or in any manner affect or conflict with State water law, Federal water law, interstate compacts, or treaty obligations. . 10. Contract services The Watershed Protection and Flood Prevention Act ( 16 U.S.C. 1001 et seq. ) is amended by inserting after section 7 (as added by section 9) the following: 8. Contract services (a) In general (1) Securing services A local organization may secure services, including for the planning, design, preparation of contracts and specifications, awarding of contracts, and supervision of construction, in connection with works of improvement, if— (A) the Secretary and the interested local organization have agreed on a plan for the works of improvement; (B) the Secretary, in consultation with the delegated authority under section 3(c), has determined that the benefits exceed the costs, except that the benefits of fish and wildlife habitat or water quality improvement shall not be required to be monetized to be considered against costs; (C) the local organization has met the requirements for participation in carrying out the works of improvement described in section 7