Iowa Code § 468.400
When proceedings for the drainage of lands bordering upon the state line are had and the total cost of constructing the improvement in this state, including all damage, has been ascertained, and the engineer in charge, before the final establishment of the district, reports that the establishment and construction of such improvement ought to be jointly done with like proceedings for the drainage of lands in the same drainage area in such an adjoining state and that drainage proceedings are pending in such state for the drainage of such lands, the said authorities of this state may enter an order continuing the hearing on the establishment of such district to a fixed date, of which all parties shall take notice.
Iowa Code § 468.400
89 Acts, ch 126, §2