Until payment, or provision for payment, has been made of all principal, interest, and any other amounts owing on account of any outstanding bonds, contracts, or other obligations which are payable in whole or in part from the revenues of a revenue-producing enterprise of the merged district, the city shall not sell, encumber, or otherwise dispose of all or any part of the revenue-producing enterprise or the revenues derived from the enterprise, except as expressly authorized by the ordinance, resolution, or indenture authorizing the bonds, contracts, or other obligations or providing for the issuance of any bonds, contracts, or other obligations.