Iowa Code 1.3 – Concurrent jurisdiction

Jurisdiction: (1) The legal authority of a court to hear and decide a case. Concurrent jurisdiction exists when two courts have simultaneous responsibility for the same case. (2) The geographic area over which the court has authority to decide cases.
state: when applied to the different parts of the United States, includes the District of Columbia and the territories, and the words "United States" may include the said district and territories. See Iowa Code 4.1

The state has concurrent jurisdiction on the waters of any river or lake which forms a common boundary between this and any other state.