Bonds authorized to be issued under the provisions of this act shall be issued as provided by law, and it shall be the duty of the board of county commissioners of any such county issuing such bonds, annually, at the time of levying other taxes, to levy a tax each year on all of the taxable property of said county, sufficient to pay the interest of said bonds, as it becomes due, and the principal thereof as such bonds mature.
K.S.A. 19-1512