The board of directors, in certifying annual levies for the subdistrict, shall take into account the maturing indebtedness for the ensuing year as provided in its contracts, maturing bonds and interest on bonds, and deficiencies and defaults of prior years and shall make ample provision for the payment thereof. In case the moneys produced from such levies, together with other revenues of the subdistrict, are not sufficient to pay punctually the annual installments of its contracts or bonds and interest thereon and to pay defaults and deficiencies, the board shall make such additional levies of taxes as may be necessary for such purposes, and such taxes shall be made and shall continue to be levied until the indebtedness of the subdistrict is fully paid.L. 79: Entire section added, p. 1359, § 6, effective May 31.