Mont. Code Ann. § 7-13-2219

The board of directors shall have power to construct works across any stream of water, watercourse, street, avenue, highway, railway, canal, ditch, or flume which the route of said works may intersect or cross; provided such works are constructed in such manner as to afford security for life and property; and said board shall restore the crossings and intersections to their former state as near as may be or in a manner not to have impaired unnecessarily their usefulness.