The Kansas River near De Soto
|- left||Republican River, Big Blue River|
|- right||Smoky Hill River, Wakarusa River|
|- location||Geary County, Kansas|
|- location||Wyandotte County, Kansas|
|Length||148 mi (238 km) |
|Basin||60,114 sq mi (155,695 km2)|
|- average||7,240 cu ft/s (205 m3/s)|
|- max||133,172 cu ft/s (3,771 m3/s)|
|- min||353 cu ft/s (10 m3/s)|
The Kansas River (also known as the Kaw) (Lenape: Kansiai Sipu ) is a river in northeastern Kansas in the United States. It is the southwestern-most part of the Missouri River drainage, which is in turn the northwestern-most portion of the extensive Mississippi River drainage. Its name (and nickname) come from the Kanza (Kaw) people who once inhabited the area. The state of Kansas in turn drew its name from the river.
The river valley averages 2.6 miles (4.2 km) in width, with the widest points being between Wamego and Rossville, where it is up to 4 miles (6.4 km) wide, then narrowing to 1 mile (1.6 km) or less in places below Eudora. Much of the river's watershed is dammed for flood control, but the Kansas River is generally free-flowing and has only minor obstructions, including diversion weirs and one low impact hydroelectric dam.
Beginning at the confluence of the Republican and Smoky Hill rivers, just east of aptly named Junction City (1,030 feet or 310 metres), the Kansas River flows some 148 miles (238 km) generally eastward to join the Missouri River at Kaw Point (730 feet or 220 metres) in Kansas City. Dropping only 320 feet (98 m) on its journey seaward, the water in the Kansas River falls less than 2 feet per mile (38 cm/km). The Kansas River valley is only 115 miles (185 km) long; the surplus length of the river is due to meandering across the floodplain. The river's course roughly follows the maximum extent of the Kansan glaciation, and the river likely began as a path of glacial meltwater drainage. 
The Kansas drains 34,423 square miles (89,160 km2) of land in Kansas (almost all of the northern half), along with 16,916 square miles (43,810 km2) in Nebraska and 8,775 square miles (22,730 km2) in Colorado, making a total of just over 60,000 square miles (160,000 km2). When including the Republican River and its headwater tributaries, the Kansas River system has a length of 743 miles (1,196 km), making it the 21st longest river system in the United States. Its highest headwaters are at about 6,000 feet (1,800 m) and extend nearly to Limon, Colorado. Much of the drainage of the river lies within the Great Plains, but the river itself exists entirely within the Mid Continent Region. The majority of the rest of the state is drained by the Arkansas (and its tributaties, the Neosho, Cimarron, and Verdigris, all three of which drain into the Arkansas in Oklahoma). A portion of central-eastern Kansas is drained by the Marais des Cygnes River, which then flows into Missouri to meet the Missouri River. There is also a small area in the extreme northeast part of the state that drains directly into the Missouri. In the Kansas City metro area, some streams drain east into the Blue River tributary of the Missouri.
Because of the river's shallow depth, slow drainage, high silt contents, and proximity to industrial centers, the Kansas River was ranked as the 21st most polluted water body in the United States.
The Kansas River flows through what is known as the Stable Interior region. Since this region is near the center of the North American Plate, it has not experienced any extensive geologic faulting, folding, or mountain building in recent geologic time. In fact, the river flows through limestone and shale strata that, except for diagenesis, remain largely undisturbed since deposition beneath the Western Interior Seaway. The age of the rock exposed by the river becomes progressively older as the river moves downstream for two main reasons. First, downstream areas experience more erosion from increased flow, and second because the slight uplift of the Ozark dome to the southeast caused the strata in Kansas to dip very slightly to the west.
All of the rocks in the area are sedimentary, ranging from Late Pennsylvanian (300 million years ago) to recent, with three minor exceptions. The first is sand and gravel brought down from the Rocky Mountains which have settled in the western extents of the Kansas River basin. Second, the retreat of the Kansan glaciation left behind a combination of ice- and meltwater-deposited sediments known as drifta, a poorly sorted mixture of clay, sand, gravel, and even large boulders that cover parts of the extreme eastern portion of the Kansas River basin. The third is loess, a fine silt that may have originally been deposited by the melting water of the receding glaciers, then redeposited by the wind. The thickest loess deposits can be found in the northwest and north-central part of the Kansas River basin from southern Nebraska into northwest Kansas, as well as near the river's mouth.
The first map showing the Kansas River is French cartographer Guillaume de L'Isle's "Carte de la Louisiane," which was drawn about 1718. On it the "Petite Riv[iere] des Cansez" flows into the Missouri River at about the 40th parallel. This map, with virtually no changes except for the translation of French into English, was subsequently published by John Senex, a London cartographer and engraver, in 1721.
Native Americans, of course, used the river for transportation long before any Europeans knew of its existence. Their canoes, and the pirogues of the French fur traders, had a negligible draft and easily navigated the river at any water level. From June 26 through 29, 1804, The Lewis and Clark Expedition camped at Kaw Point at the river's mouth. They complimented the scenery and noted the area would be a good location for a fort.
In August, 1819, Maj. Stephen H. Long steered the first steamer into the Kansas river with his 30-ton boat Western Engineer. He made it scarcely a mile up the river before turning back, citing mud bars from the recent floods.
The mouth of the Kansas River in the West Bottoms area of Kansas City (sitting at a longitude of 94 degrees 36 minutes West) was the basis for Missouri's western boundary from Iowa to Arkansas when it became a state in 1821. (Kansas entered the Union in 1861.) South of the Missouri River, that longitude still remains the boundary between Kansas and Missouri. North of the Missouri River, the state of Missouri extended its boundary further to the west in 1836 with the Platte Purchase. The river has moved slightly since this designation, but the state boundary has remained the same. This line is known as the Osage Boundary.
Beginning in 1854, steamboats operated regularly from Kansas City to Lawrence and Topeka, and sometimes as far as Fort Riley. This traffic continued through the territorial period and the early years of statehood, falling off rapidly about 1860. The last steamer to travel the Kansas was the Alexander Majors, which was chartered in 1866 to run between Kansas City and Lawrence until the railroad bridge at the mouth of the river, which had been destroyed by floods, could be rebuilt. This traffic into statehood gave the Kansas legal status as a navigable stream in the eyes of the Federal government. In the 1860s, the country's goods were increasingly transported by the extensive and comparatively efficient railroad system.
On February 25, 1864, the state legislature declared the Kansas River nonnavigable, allowing railroad and bridge companies to build bridges and dams without restriction. This law remained in effect until 1913, when, after it had been characterized as "a crime against the public welfare of Kansas", it was finally repealed and the river's status was restored to a navigable stream. The status has not since changed, though modern commercial navigation on the river is largely confined to dredging.
Recreation along the Kansas River includes fishing, canoeing and kayaking, and rowing. There are 18 public access points along the river. The Friends of the Kaw organizes many float trips down the river each year (as well as cleanup efforts), and the Lawrence KOA rents canoes for self-guided trips. At least two rowing teams regularly use the river: The University of Kansas rowing team uses the pool above the Bowersock dam for their exercises, and the Kansas City Rowing Club rows in the final stretches of the river, near its mouth.
River modifications 
On the river 
- Kansas City: A few yards downstream from the I-435 bridge, a weir diverts water to an intake for WaterOne. Portage access is on the left bank.
- Lawrence: Bowersock Dam is the largest obstruction on the river. It serves not only to create a standing pool for one of Lawrence's municipal water intakes (the other is at Clinton Lake), but also it creates a head for the Bowersock Mills & Power Company. At this site, the Bowersock Mills & Power Company operates the only hydroelectric power station in Kansas: a 2.5 MW, Low Impact Hydropower Facility. The University of Kansas's rowing team uses the pool for its exercises. Portage access is on the left bank.
- Tecumseh: An easily navigable low head weir exists that diverts water to the Tecumseh power plant, just downstream from Topeka.
- Topeka: A Topeka water department dam diverts water to the right bank for a municipal water intake. Portage access is on the left bank.
Within the watershed 
The U.S. Army Corps of Engineers and the Bureau of Land Management operate many reservoirs within the watershed of the Kansas river for local and Mississippi River flood control, with secondary recreational uses.
Along the river 
(Listed from mouth upstream.)
- Wyandotte and Johnson (boundary in part)
- Jefferson and Douglas (boundary)
- Pottawatomie and Wabaunsee (boundary)
Cities and towns 
|Boldface denotes a major city|
See also 
- U.S. Geological Survey Geographic Names Information System: Kansas River
- U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. The National Map, accessed May 31, 2011
- "Lenape Talking Dictionary". Retrieved 2012-05-27.
- "Kansas history page". Retrieved 2006-11-28.
- The Encyclopedia of Kansas (1994) ISBN 403-09921-8
- environmental news service
- KGS-Kansas River Corridor-Geology
- Lengths of major rivers
- A Review of Early Navigation on the Kansas River, Kansas Historical Quarterly, May 1950, Volume 18, No. 2, Kansas State Historical Society
- INDIAN AFFAIRS: LAWS AND TREATIES. Vol. 2, Treaties
|Wikimedia Commons has media related to: Kansas River|
|Wikisource has the text of the 1921 Collier's Encyclopedia article Kansas River.|