If the said boards shall adopt a tentative plan for the district, the board of each county shall select an appraiser and the several boards by joint action shall employ an engineer, and the said appraisers and engineer shall constitute the appraisers to appraise the damages and value of all right-of-way required for open ditches and of all lands required for settling basins.
Iowa Code § 468.279
89 Acts, ch 126, §2