(a) The department, by written order, may require the owner of a public or private dam or other obstruction on a regularly flowing public freshwater stream to construct or repair fishways or fish ladders sufficient to allow fish in all seasons to ascend or descend the dam or other obstruction for the purpose of depositing spawn.
(b) An owner who fails to construct or repair a fishway or fish ladder within 90 days after receiving the written order commits an offense. Each week of violation following the 90-day period constitutes a separate offense.