Mont. Code Ann. § 85-1-208

85-1-208 . Construction across streams, highways, or other obstacles. (1) The department may construct irrigation works across any stream of water, watercourse, streets, avenues, highways, railways, canals, ditches, or flumes in such manner as to afford security to life and property. The department shall restore the same, when so crossed or intersected, to its former state, as near as may be, so as not to destroy its usefulness. A company whose railroads are intersected or crossed by the works shall unite with the department in forming the intersection and crossing. If the railroad company and the department or the owners and controllers of the property, thing, or franchise so to be crossed cannot agree upon the amount to be paid therefor or the points or the manner of the crossing or intersections, the amount shall be ascertained and determined in all respects as herein provided in respect to taking of land for public use.

(2) This section does not require the payment to the state or any subdivision thereof of a sum for the right to cross a public highway with the works. A right-of-way is hereby given, dedicated, and set apart to locate, construct, and maintain the works over and through the lands which are the property of this state.