16 U.S.C. § 460l: Non-Federal administration of project land and water areas

the benefits of the project to said purpose or purposes shall be taken into account in determining the economic benefits of the project; costs shall be allocated to said purpose or purposes and to other purposes in a manner which will insure that all project purposes share equitably in the advantages of multiple-purpose construction: Provided , That the costs allocated to recreation or fish and wildlife enhancement shall not exceed the lesser of the benefits from those functions or the costs of providing recreation or fish and wildlife enhancement benefits or reasonably equivalent use and location by the least costly alternative means; and not more than one-half the separable costs of the project allocated to recreation and exactly three-quarters of such costs allocated to fish and wildlife enhancement and all the joint costs of the project allocated to recreation and fish and wildlife enhancement shall be borne by the United States and be nonreimbursable. The non-Federal share of the separable costs of the project allocated to recreation and fish and wildlife enhancement shall be borne by non-Federal interests, under either or both of the following methods as may be determined appropriate by the head of the Federal agency having jurisdiction over the project: (1) payment, or provision of lands, interests therein, or facilities for the project; or (2) repayment, with interest at a rate comparable to that for other interest-bearing functions of Federal water resource projects, within fifty years of first use of project recreation or fish and wildlife enhancement facilities: Provided , That the source of repayment may be limited to entrance and user fees or charges collected at the project by non-Federal interests if the fee schedule and the portion of fees dedicated to repayment are established on a basis calculated to achieve repayment as aforesaid and are made subject to review and renegotiation at intervals of not more than five years.