16 U.S.C. § 590z-6
All payments made to the United States under repayment contracts on account of reimbursable construction costs, including penalties collected for delinquencies in such payments, and all other receipts from project operations pursuant to sections 590z-2 and 590z-7 of this title shall be covered into the Treasury to the credit of miscellaneous receipts. Charges collected during the development period of a project under section 590z-2(c)(1) of this title, excepting such amounts thereof as may be credited to reimbursable construction costs, and charges collected for the operation and maintenance of a project under section 590z-2(c)(2) of this title shall be available for expenditure for operation and maintenance of said project in like manner as if said funds had been specifically appropriated for said purposes.
16 U.S.C. § 590z-6