The board of directors, in certifying annual levies for the district, shall take into account the maturing indebtedness incurred by the district by contract other than the issuance of bonds for the ensuing year as provided in its contracts 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 district, are not sufficient to pay punctually the annual installments of such contracts 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 district is fully paid.L. 79: Entire section added, p. 1356, § 3, effective May 31.