Ala. Code § 2-6-116

All proceeds derived from the sale of any bonds, excluding refunding bonds, sold by the corporation remaining after payment of the expenses of issuance thereof and the funding of any required reserve or replacement fund shall be deposited into a special account to the credit of the corporation, and shall be subject to be drawn on by the corporation solely for the purposes of paying the costs of the project work, and all reasonable and necessary incidental expenses, including interest which shall accrue on the bonds during the project work and for a period not exceeding two years thereafter. Any balance of the proceeds remaining, upon completion of the project work and the payment of all costs in connection therewith, shall be transferred to the debt service reserve fund account of the corporation or used to redeem bonds issued by the corporation as may be determined by the board of directors of the corporation.