Hydrography
The Des Moines River rises in two forks. The West Fork (the main branch) rises out of Lake Shetek in Murray County in southwestern Minnesota. It flows south-southeast into Emmet County, Iowa, past Estherville. The East Fork rises out of Okamanpeedan Lake in northern Emmet County on the Iowa-Minnesota border and flows south, through Algona.
The two forks join in southern Humboldt County, approximately 5 miles (8 km) south of Humboldt at Frank Gotch State Park. The combined stream flows roughly southward through Fort Dodge. South of Boone it passes through the Ledges State Park. It flows through downtown Des Moines, then turns generally southeastward, flowing through Ottumwa. It forms approximately 20 miles (32 km) of the border between Iowa and Missouri before joining the Mississippi from the northwest at Keokuk.
It receives the Boone River from the northeast approximately 20 miles (32 km) southwest of Fort Dodge. It receives the Raccoon River from the west in Des Moines. Above the city of Des Moines, it is impounded to create the Saylorville Lake reservoir. About midway below Saylorville and above Ottumwa, near Pella, it is impounded to create the Lake Red Rock reservoir.
Read more about this topic: Des Moines River