Ala. Code § 11-55-4
The principal of and interest on any bonds issued under the authority of this chapter shall be secured by a pledge of the revenues out of which such bonds shall be made payable, may be secured by a mortgage covering all or any part of the project from which the revenues so pledged may be derived and may be secured by a pledge of the lease of such project.
The proceedings under which such bonds are authorized to be issued or any such mortgage may contain any agreements and provisions customarily contained in instruments securing bonds, including, without limiting the generality of the foregoing, provisions respecting the fixing and collection of rents for any project covered by such proceedings or mortgage, the terms to be incorporated in the lease of such project, the maintenance and issuance of such project, the creation and maintenance of special funds from the revenues from such project and the rights and remedies available in event of default to the bondholders or to the trustee under a mortgage as the governing body shall deem advisable and as shall not be in conflict with the provisions of this chapter; provided, however, that in making any such agreements or provisions a municipality shall not have the power to obligate itself except with respect to the project and the application of the revenues therefrom and shall not have the power to incur a pecuniary liability or a charge upon its general credit or against its taxing powers.
The proceedings authorizing any bonds under this chapter and any mortgage securing such bonds may provide that, in the event of default in payment of the principal of or the interest on such bonds or in the performance of any agreement contained in such proceedings or mortgage, such payment and performance may be enforced by mandamus or by the appointment of a receiver with power to charge and collect rents and to apply the revenues from the project in accordance with such proceedings or the provisions of such mortgage. Any such mortgage may provide also that, in the event of default in such payment or the violation of any agreement contained in the mortgage, the mortgage may be foreclosed either by sale at public outcry or by civil action and may provide that any trustee under such mortgage or the holder of any of the bonds secured thereby may become the purchaser at any foreclosure sale if the highest bidder therefor. No breach of any such agreement shall impose any pecuniary liability upon a municipality or any charge upon its general credit or against its taxing powers.
Ala. Code § 11-55-4 (1975)