Neb. Rev. Stat. § 39-1636

Each time any improvement is made to any road, street, or highway in the district, a copy of the plans and specifications shall be filed in the office of the county highway superintendent of the county or counties in which such district is located. After the court decree of validation has been entered, a copy of the pleadings and showings, as well as the final decree of the court, shall be filed in the office of the county clerk and the county engineer in the county or counties in which the road improvement district is located.