The use and disposition of such sinking fund shall be subject to such regulations as may be provided in the resolution authorizing the issuance of the revenue bonds or in the trust indenture, but, except as may otherwise be provided in the resolution or trust indenture, the sinking fund shall be a fund for the benefit of all revenue bonds without distinction or priority of one over another. Subject to the provisions of the resolution authorizing the issuance of the revenue bonds or the trust indenture, any moneys in such sinking fund in excess of an amount equal to one year's interest on all revenue bonds then outstanding may be applied to the purchase or redemption of bonds. All revenue bonds so purchased or redeemed shall forthwith be canceled and shall not again be issued.
OCGA § 52-2-31