(1) The county board shall have authority to direct landowners to remove, from ditches and watercourses adjoining or within the boundaries of their premises, obstructions which the landowners have placed or permitted to be placed therein, including the removal of inadequate culverts, crossings and bridges.

(2) If an inadequate bridge, culvert or crossing has been in or over a ditch or watercourse for more than one year prior to September 28, 1959, the cost of removal or replacement shall be paid either from the county road fund, the county drainage fund or from the assessments under an improvement project conducted under sections 31-907 to 31-920.

(3) Where the removal of such obstruction is not to be payable out of special funds as provided for in subsection (2) of this section, the board, after thirty days' notice by certified mail, to the owner, may remove the obstruction and assess the costs thereof against such owner in the manner provided in section 31-916; Provided, the owner shall have the right to appeal from the order in the manner provided for in section 31-911.