| Walnut River | |
| Name Other: | Little Verdigris River |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | Kansas |
| Subdivision Type5: | Cities |
| Subdivision Name5: | Arkansas City, Winfield, El Dorado |
| Length: | 154miles, North-South |
| Source1 Location: | Near Cassoday, Kansas, United States |
| Source1 Coordinates: | 38.0214°N -96.5533°W[1] |
| Source1 Elevation: | 1473feet |
| Mouth: | Arkansas River |
| Mouth Location: | Near Arkansas City, Kansas, United States |
| Mouth Coordinates: | 37.0492°N -97.0006°W |
| Mouth Elevation: | 1043feet |
| River System: | Arkansas River watershed |
The Walnut River is a tributary of the Arkansas River, long,[2] in the Flint Hills region of Kansas in the United States. Via the Arkansas, it is part of the Mississippi River watershed.
According to the GNIS, the river has also been known in the past as the "Little Verdigris River".
The Walnut River rises in northern Butler County and flows generally southward through Butler and Cowley Counties, past the towns of El Dorado, Augusta, Winfield and Douglass. It joins the Arkansas River at Arkansas City. The Walnut's principal tributaries are the Whitewater River, which joins it at Augusta, and the Little Walnut River, which joins it in southern Butler County. The Walnut River drainage basin comprises in an ecoregion characterized by rocky, rolling hills and prairie. Elevations range from 1050to in the basin. Average precipitation, mostly summer rainfall, varies from 32to annually. Tallgrass prairie is the most common vegetation, covering 66 percent of the land. Crop land covers 23 percent and woodlands cover five percent. Major crops are wheat, soybeans, cotton, hay, sorgum, and corn. Cattle are the most important livestock.[3]
Upstream of El Dorado, a U.S. Army Corps of Engineers dam causes the river to form El Dorado Lake, along which a Kansas state park has been designated. The lake consists of about of water with another 8,000 acres of land along its shores designated as park and wildlife areas.[3] The other large lake in the Walnut River basin is Winfield City Lake with of water surrounded by of parkland.[4] Both lakes offer recreational opportunities including fishing, boating, hunting, camping, and wildlife observation.
In Winfield, the east side of the old Tunnel Mill Dam is a public fishing spot. It is staged directly near the old Kickapoo Corral. The west side of the dam and the Kickapoo Corral are both privately owned and closed to the public. A whirlpool is created by a hole in solid limestone about down on the river bed directly off the cliffs of the Corral. The bottom is sandy and somewhat rocky.
Near the mouth of the Walnut River, in eastern Arkansas City, are a large number of archaeological sites, including the historical city of Etzanoa, a Wichita settlement that flourished between 1450 and 1700 and housed perhaps 20,000 people.[5] This site was visited in 1601 by New Mexico governor Juan de Oñate.[6] [7] [8]
The Walnut Valley Festival is held along the banks in Winfield.