Cottonwood River Flooding

Flooding is a recurring event in the Neosho River basin of east-central and southeastern Kansas. Both flash floods and long-term flooding have taken place in various parts of the basin. Thin soil and shaly bedrock contribute to rapid runoff during precipitation events. The region is subject to intense storms, especially during the late spring and early summer and again in autumn. The Neosho River and its principal tributary, the Cottonwood River, occupy wide valleys, large portions of which may be submerged during floods.

In recent years, the Cottonwood River has flooded several times at Emporia. Most of the city of Emporia is situated on a terrace that is above flood water, but some low-lying sections of the city are subject to inundation. The nearest upstream gauging station is at Plymouth, about 8 miles (13 km) west of Emporia--see historical streamflow data for the lower Cottonwood River near Plymouth, Kansas. The Plymouth streamflow record began in 1964; flood stage at this station is 32 feet. Normal, low-flow stage is in the range 6-10 feet.

The "Halloween" flood of 1998 is the largest on record for this gauging station. This flood resulted from 8-10 inches of rain over the drainage basin during a two-day period, Oct. 31 and Nov. 1, 1998. This flood is estimated to have a 50- to 100-year recurrence interval, and reached a peak stage of 36.8 feet.

Multiple floods took place during 2004. The first was in early March and reached a stage height of 33.0 feet (see charts below). A second interval of flooding happened during several weeks beginning in mid June until late July. Three times river level reached 30-foot stages, and the 32-foot flood stage was exceeded in early July. Flooding continued the following year with another overbank flow in June 2005, and again in 2007 and 2008. From the record below, it's clearly apparent that flooding is possible during spring, summer or autumn; only the winter months are relatively safe from floods.

**Recent flood events at the Plymouth gauging station.**
Date	Gauge height *
June 5, 1965	35.7 feet
June 27, 1969	34.5 feet
Oct. 11, 1973	34.7 feet
Oct. 10, 1985	35.5 feet
May 10, 1993	35.0 feet
May 27, 1995	33.6 feet
Nov. 2, 1998	36.8 feet
Mar. 5-6, 2004	33.0 feet
early July 2004	32.5 feet
June 13, 2005	32.9 feet
May 8, 2007	33.5 feet
Sept. 15, 2008	33.5 feet**

Flood stage = 32.0 feet. Normal stage <10 feet.
* Gauge height rounded to 0.1 foot.
** Provisional figure.

Cottonwood River flood of March 2004

Cottonwood River flood of May 1969

Following are aerial views of the May, 1969 flood of the Cottonwood River at Emporia, Kansas. Photographs courtesy of DeWayne Backhus.

View northward across the Cottonwood valley south of Emporia, which is visible on the far horizon.

Cottonwood River on south side of Emporia. The river channel is shown by the meandering line of trees. The large body of clean water (lower left) is within a gravel pit. The city is situated a terrace that stands several meters above the floodplain.

Inundated agricultural fields of the Cottonwood floodplain near Emporia, Kansas. Note the intricate pattern of meandering channels.

The city of Emporia experienced a flash flood of the central business district the evening of May 30, 2006. More than 3 inches of rain fell during an heavy thunderstorm. Businesses along Commerical Street from about 9th to 6th were flooded, as storm sewers were unable to handle the sudden downpour. Abandoned vehicles floated in water-filled street underpasses (under BNSF railroad). Such intense, highly localized storms may create flash floods, particularly in urban settings, but have little impact on downstream flow of larger rivers.