The Nodaway River is a low gradient, sixth order river that originates in Adair County, Iowa and flows southward for about 120 miles before emptying into the Missouri River near the town of Nodaway, Missouri. The watershed drains 1,820 square miles with 68% in Iowa and 32% in Missouri. Characterized by turbid water and substrates of silt and sand, the Nodaway is typical of altered prairie streams. Extensive channelization has eliminated 248 miles of stream, with only the lower 11 miles remaining in a natural, unchannelized state. The river has an average annual discharge of 1,018 cubic feet per second at Graham, Missouri and experiences highly variable flows that rise and subside swiftly in response to precipitation events.