(a) It is unlawful for any person, until the department's permit has been granted, to modify any protected stream or any part of the stream. A permit may not be issued unless the work proposed to be done under the permit:
(1) Will not materially alter or affect the free-flowing characteristics of a substantial part of a protected stream or streams;
(2) Is necessary to prevent an undue hardship; and
(3) Meets with the approval of the secretary.
(b) The Department of Transportation's Division of Highways is not required to obtain a permit under this section when it is repairing or replacing damaged bridges and that repair or replacement requires the construction of temporary flow diversions in the stream that will not permanently materially alter or affect the free-flowing characteristics of a substantial part of the steam, so long as boat passage remains available during the entire period of bridge repair or replacement.