The governing body shall irrevocably pledge all or a stated percentage of the special fund created under § 11-9-31 to the payment of the bonds. The special fund or designated part may be used only for the payment of the bonds and interest until the bonds have been fully paid, and any holder of the bonds or of any coupons related thereto shall have a lien against the special fund for payment of the bonds and interest and may either at law or in equity protect and enforce the lien.
SDCL 11-9-37