| Watonwan River | |
| Name Etymology: | Dakota watanwan meaning "fish bait" or "plenty of fish"[1] |
| Map: | Blueearthrivermap.png |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | Minnesota |
| Subdivision Type3: | Counties |
| Subdivision Name3: | Cottonwood, Watonwan, Blue Earth |
| Length: | 113.2miles[2] |
| Discharge1 Location: | near Garden City[3] |
| Discharge1 Min: | 1.8cuft/s |
| Discharge1 Avg: | 391cuft/s[4] |
| Discharge1 Max: | 13900cuft/s |
| Source1 Location: | Amboy Township, Cottonwood County |
| Source1 Coordinates: | 44.025°N -95.22°W[5] |
| Source1 Elevation: | 1529feet[6] |
| Mouth: | Blue Earth River |
| Mouth Location: | Rapidan Township, Blue Earth County |
| Mouth Coordinates: | 44.0703°N -94.1264°W |
| Mouth Elevation: | 879feet |
| Basin Size: | 878sqmi[7] |
| Tributaries Left: | North Fork Watonwan River |
| Tributaries Right: | South Fork Watonwan River |
The Watonwan River is a tributary of the Blue Earth River, long, in southern Minnesota in the United States. Via the Blue Earth and Minnesota rivers, it is part of the watershed of the Mississippi River, draining an area of in an agricultural region. The Watonwan drains about a quarter of the Blue Earth River's watershed.[8]
The river was the site of the capture of Bob, Cole and Jim Younger (members of the James–Younger Gang) near Madelia in 1876.[9]
The Watonwan River rises in Amboy Township, approximately 3miles southwest of Jeffers in central Cottonwood County, and flows generally eastwardly across flat till plains through northern Watonwan and western Blue Earth counties, past the city of Madelia. It flows into the Blue Earth River approximately 8miles southwest of Mankato and upstream of the Blue Earth's confluence with the Minnesota River.[8] [10] [11]
The river's largest tributaries are its north and south forks. The South Fork Watonwan River,[12] long, rises in southeastern Cottonwood County and initially flows eastwardly into southern Watonwan County, briefly entering Martin County and passing Odin; then northeastwardly through eastern Watonwan County to its confluence with the Watonwan River upstream of Madelia. The North Fork Watonwan River,[13] long, rises in Cottonwood County and flows eastwardly into northern Watonwan County, joining the Watonwan River about a mile (2 km) southeast of La Salle.[2] [10]
Approximately 84% of the larger watershed of the Blue Earth River, which includes that of the Watonwan River, is used for agricultural cultivation, primarily that of corn and soybeans.[8] Small lakes and wetlands in the Watonwan watershed provide significant habitat for Minnesota's waterfowl population, though many stretches of the river and its tributaries have been subject to ditching and channelization for agricultural production and localized flood reduction.[9]
At the United States Geological Survey's stream gauge near the community of Garden City in Garden City Township, upstream from the river's mouth, the annual mean flow of the river between 1940 and 2005 was 391 cubic feet per second (11 m³/s). The highest recorded flow during the period was 13,900 ft³/s (394 m³/s) on June 20, 1993. The lowest recorded flow, caused by an ice dam, was 1.8 ft³/s (0 m³/s) on December 24, 1989.[3]