Historic Floods Along Arkansas River

Description of Arkansas River Basin

At 1,450 miles, the Arkansas is the longest tributary in the Mississippi-Missouri system. From its source near Leadville, Colorado (Arkansas River Historical Society, 2003). Regulation of streamflow by storage and consumptive use in Colorado has reduced the river to a small stream where it crosses the border into Kansas. Across the plains of Kansas, the channel of the river is very shallow, with the banks being less than 5 feet above low water in some places (Blackmar, 1912). What the river channel lacks in depth it makes up for in width, being as much as 1-mile wide in some places.

As a result of land-surface characteristics and water use in Kansas, flows in the Arkansas River remain small for a considerable distance within the State, increasing gradually to Wichita where they increase due to inflows from the Little Arkansas River (Jordan, 1986). As it travels through Kansas, the Arkansas River flows through mostly agricultural areas and then exits into northeastern Oklahoma. There it is joined by the Canadian, Cimarron, Neosho-Grand, and Verdigris Rivers. It then crosses the State of Arkansas and empties into the Mississippi River 600 miles north of New Orleans (Arkansas River Historical Society, 2003).

The Arkansas River Basin in Kansas can be divided into two subunits--the upper Arkansas River Basin and the lower Arkansas River Basin. The Arkansas River Basin as a whole has a relatively low potential for runoff as soil permeability is generally high and precipitation is generally low (Juracek, 1999). This low potential for runoff along with relatively flat to gently rolling terrain throughout its basin results in generally localized flooding that is mostly confined to areas immediately affected by excessive rains.

Effects of Human Development on Streamflows

Prior to the early 1880s, there was always an abundance of water in the river, and the channel, even down to the Little Arkansas River near Wichita, was usually full. Occasionally, however, the river was a bed of dry sand above the confluence of the Little Arkansas for a couple of months in the fall. During prolonged dry spells, water in the channel has been known to disappear suddenly, only to make its reappearance as unexpectedly within the next day or two (Root, 1936).

Development of the Arkansas River Basin in western Kansas began with diversions for irrigation of corn and sugar beets (Jordan, 1986). From 1880-1905, 12 irrigation canals were constructed to divert water from the Arkansas River between the Colorado State line and Great Bend, Kansas. These 12 canals were intended to irrigate from 5,000 to 100,000 acres. From 1900-10, irrigation wells began to be constructed in the Arkansas River Valley. Well development occurred because of the rapid expansion of irrigation in Colorado, which caused flow in the Arkansas River to cease during July and August when water was so sorely needed by Kansas irrigators. Well water could be obtained at depths of 6 to 20 feet. These early wells were constructed to supplement river flows, not to replace river water; however, by 2000, direct water withdrawals from the river for irrigation had deceased to supply water for only about 50,000 acres of Kansas land (C.V. Hansen, U.S. Geological Survey, written commun., 2003).

The considerable development of the Arkansas River in Colorado, including construction of John Martin Reservoir, completed in 1943 with 702,000 acre-feet or 227,000 million gallons of storage capacity, also affects flows of the river in western Kansas. Cheyenne Bottoms—a waterfowl and fishing area in Barton County enlarged from a natural shallow lake— - and Quivira National Wildlife Refuge in Stafford County are maintained in part by diversions from the Arkansas River and its tributaries. Other developments include diversions of floodwaters around Hutchinson, Wichita, and Valley Center, and a pipeline from Cheney Reservoir to Wichita (Jordan, 1986).

The Wichita and Valley Center Local Protection Project, authorized by the Flood Control Act (Public Law 738), was approved on June 22, 1936, and consists of levees, floodways, improved channels, and control structures on the Arkansas and Little Arkansas Rivers and Chisholm Creek in Sedgwick County, south-central Kansas. Construction of the project began in May 1950 and was completed in March 1959. The project provides flood protection for approximately 49,000 acres of urban and rural lands in and adjacent to the cities of Wichita and Valley Center (U.S. Army Corps of Engineers,1996).

The apparent downward trend of annual peak flows at the U.S. Geological Survey (USGS) streamflow-gaging station on the Arkansas River at Syracuse is the result of consumptive use of water for irrigation and storage in reservoirs. Decreasing streamflows have forced the decrease of irrigation by surface water from the Arkansas River and also has decreased the quantity of water available for the Cheyenne Bottoms and Quivira waterfowl areas. In contrast, annual peak flows of the Arkansas River at Wichita have not shown a downward trend despite ground-water withdrawals from the adjacent Equus Beds aquifer for public supply in the Wichita area.