Iowa Code § 311.25: Appeal docketed.

When an appeal is taken, the county engineer shall make a transcript of the notice of appeal and appeal bond and transmit them to the district court. The appellant shall, within twenty days after perfection of the appeal, docket the appeal and file a petition setting forth the order or decision of the board of supervisors appealed from, and the appellant’s specific objections. A failure to comply with either of these requirements is a conclusive waiver of the appeal and the court shall dismiss the petition. Appellee need not file answer, but may do so.