Des Moines, river, 535 mi (861 km) long, rising in SW Minn. and flowing SE across Iowa to the Mississippi River at Keokuk, SE Iowa. Flowing through fertile farmland, the river floods in the spring and is nearly dry in late September; dams were constructed to regulate its flow. It is the main source of water for Des Moines, Iowa.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.