The board in certifying annual levies as herein provided, 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 district are not sufficient punctually to pay the annual instalments on its contracts or bonds, and interest thereon, and to pay defaults and deficiencies, then the board shall make such additional levies of taxes as may be necessary for such purposes, and notwithstanding any limitations, such taxes shall be made and continue to be levied until the indebtedness of the district shall be fully paid.