The city council, from time to time, for the purpose of maintaining the fund, may enact a general ordinance of appropriation and may levy a tax of not to exceed one mill in any one year, and may make appropriation from such other locally available sources as may be determined by the city council for the purpose of guaranteeing to the extent of the fund payment of bonds and warrants, and interest thereon, hereafter issued against any local improvement district in the city for the payment of local improvements therein. (Ord. 208 § 2, 1962)