Ala. Code § 33-1-26
In order to enable the port authority to earn funds to pay operating expenses and interest on the bonds and to create a sinking fund for the retirement of the bonds, the port authority shall have the right and power to fix from time to time reasonable rates of charges for all services and for the use of all improvements and facilities provided under the authority of this chapter; and schedules of all rates so fixed shall be filed with the State Public Service Commission within seven days after the fixing thereof. All private concerns, corporations or individuals operating similar facilities at Alabama seaports must make and collect charges which shall be not less than the charges so fixed by the department for the use of the state's facilities.
Ala. Code § 33-1-26 (1975)