Ala. Code § 33-2-202

The department, from time to time, may enter into or execute and deliver short-term obligations. Any short-term obligations shall not be general obligations of the department, but shall be payable solely from docks facilities revenues and shall be subject to repayment in not more than three years; provided, that the department may refinance or renew any short-term obligations from time to time. As security for the payment of any short-term obligations, the department is hereby authorized and empowered to pledge for payment of the short-term obligations, all or any part of its docks facilities revenues; provided, however, that any pledge of its docks facilities revenues, in the discretion of the department, may be on parity with or subordinate to the pledge securing any revenue bonds or other obligations of the department.