Ala. Code § 33-2-9

The proceeds of the handling and operation of improvements and facilities constructed pursuant to this article shall be applied as follows: All expenses of carrying out the purposes of this article shall be paid from said proceeds. Not less than 30 days before each semiannual date upon which interest matures on the bonds hereby authorized, or any installment of principal matures, the Secretary-Treasurer of the State Docks Department shall pay to the state treasury from receipts of facilities constructed pursuant to this article an amount sufficient to cover such installment of interest or principal, and therefrom the State Treasurer shall pay such interest or principal. If the receipts of the State Docks Department from facilities constructed pursuant to this article are insufficient to cover any expenses herein provided for or any installment of interest or principal, the deficiency may be paid from the proceeds of any sale of bonds hereby authorized; provided, that such use of the said proceeds shall be limited to the payment of expenses and interest on bonds for only the first three years after completion and putting into operation of the unit or units or improvement or improvements acquired with the proceeds of such bonds, or the amount necessary for the payment of such interest may be obtained from temporary loans negotiated therefor as hereinbefore authorized. It is intended to so provide that all of the revenues and income arising from operations authorized by this article and from all property acquired under the provisions of this article shall be devoted to the payment of expenses of such operation, to the payment of interest upon the bonds issued pursuant to this article, and other payment of principal of such bonds as they respectively mature, thus relieving other revenues of the state docks department, or other revenues of the state, from any burden in that behalf unless the aforesaid income shall be insufficient for the purposes mentioned. The State Docks Department may retain from the moneys coming into its hands from any facility obtained pursuant to this article such amounts as may be reasonably required for operating capital for facilities and improvements constructed pursuant to this article, and all amounts so retained shall be deemed to be an operating expense within the meaning of this article.