Expenditures from the special fund provided for in Section 45-39-92.51 shall be made exclusively for the purposes of paying principal of and interest on securities evidencing obligations incurred for payment for the Shoals Economic Development Project. All of the proceeds of the taxes herein authorized shall be specifically pledged by the Lauderdale County Commission to the payment of principal of and interest on the securities, whether such securities are issued by the county or by a local public corporation. The pledge of the taxes herein authorized for the payment of the principal of and interest on securities issued by Lauderdale County or a local public corporation, together with any applicable covenants of the county and the local public corporation relating to such pledge, shall have the force of contract between the county, the local public corporation, and the holders of the securities. The proceeds of the taxes may be deposited by the county or the State Department of Revenue, if the department is the collector of the taxes, directly with the paying agent or the trustee of the securities. Notwithstanding the foregoing provisions of this section, no monies from the special fund provided for in Section 45-39-92.51 and no proceeds of any securities shall be expended for any purpose on the Florence River Heritage Trail.