(a) The district, at its own expense, may build necessary bridges and culverts across or under any railroad tracks or roadways to enable the district to construct and maintain any canal, lateral, or ditch which is a necessary part of its improvements.
(b) Before the district proceeds to build bridges and culverts, the board shall deliver to the legal agent, division superintendent, or roadmaster written notice. The railroad company shall have 30 days in which to build the bridges and culverts at its own expense and according to its own plans.
(c) The bridges and culverts shall be placed at points designated by the board or the district engineer and shall be constructed so that they will not interfere with the free and unobstructed flow of water passing through the canal or ditch.