All proceedings except as provided in this part in relation to the establishment, construction, and management of interstate drainage districts shall be as provided for the establishment and construction of districts wholly within this state as provided in subchapter I. All such proceedings shall relate only to the lands of such district which are located wholly within this state. Boards having jurisdiction in this state may make just and equitable agreements with like authorities in such adjoining state for the joint management, repair, and maintenance of the entire improvement, after the establishment and completed construction thereof.
Iowa Code § 468.405
89 Acts, ch 126, §2