All improvements and facilities constructed pursuant to the joint issuance of bonds by any county and municipality under the authority of Sections 59-9-57 and 59-9-59, shall be maintained and operated under the control of the county port authority and of the port commission. The county port authority and port commission shall, subject to and in accordance with any agreement or agreements as may be made by any such county and municipality with the purchaser or purchasers of bonds or other obligations issued pursuant to this chapter, prescribe, levy, and collect all rents, fees, tolls, revenues and other charges in connection with the use and occupancy of the aforesaid improvements and facilities, and shall pay over all net revenues derived from the operation of such improvements and facilities to any trustee, or successor thereto, established as hereinafter in this chapter provided. Net revenues shall be deemed to be such as may be defined in any agreement or agreements entered into between any such county and municipality and the purchaser or purchasers of any bonds or other obligations issued pursuant to the aforesaid sections.