Neb. Rev. Stat. §§ 39-805
Whenever any public highway within this state shall cross or be crossed by any ditch or channel of any public drainage or irrigation district, it shall be the duty of the governing board of the drainage or irrigation district and the governing board of the county or municipal corporation involved to negotiate and agree for the building and maintenance of bridges and approaches thereto on such terms as shall be equitable, all things considered, between such drainage or irrigation district and such county or municipality. If such boards for any reason shall fail to agree with reference to such matter, it shall be the duty of the drainage or irrigation district to build the necessary bridges and approaches, and restore the highway in question to its former state as nearly as may be as it was laid out prior to the construction of the ditch or channel in question, and it shall be the duty of the county or municipal corporation involved to maintain the bridges and approaches. Where more than seventy-five percent of the water passing through any such ditch or channel is used by any person, firm, or corporation for purposes other than irrigation or drainage, it shall be the duty of such person, firm, or corporation, so using such seventy-five percent or more of such water, to build and maintain solely at the expense of such person, firm, or corporation, all such bridges and approaches thereto. Any bridge that may be built by any drainage or irrigation district or by any person, firm, or corporation under the provisions of this section shall be constructed under the supervision of the Department of Transportation, if on a state highway, and under the supervision of the county board or governing body of a municipality, if under the jurisdiction of such board or governing body of such municipality.
Neb. Rev. Stat. §§ 39-805