S.C. Code Ann. § 11-15-600

Any issuer having outstanding special obligation bonds authorized by any special act of the General Assembly enacted prior to March 7, 1973, may utilize the procedure prescribed by this article to effect the refunding of such special obligation bonds, except that for the payment of the principal of and interest on such refunding bonds there shall be pledged all or any part of the revenues securing the outstanding bonds, and any and all covenants as may be deemed necessary or desirable may be made to implement such pledges.