The Big Sioux River is a

tributary A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drai ...

of the Missouri River in eastern

South Dakota South Dakota (; Sioux: , ) is a U.S. state in the North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Lakota and Dakota Sioux Native American tribes, who comprise a large po ...

and northwestern

Iowa Iowa () is a U.S. state, state in the Midwestern United States, Midwestern region of the United States, bordered by the Mississippi River to the east and the Missouri River and Big Sioux River to the west. It is bordered by six states: Wiscon ...

in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

. It flows generally southwardly for ,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data
The National Map
, accessed March 30, 2011 and its watershed is . The

United States Board on Geographic Names The United States Board on Geographic Names (BGN) is a federal body operating under the United States Secretary of the Interior. The purpose of the board is to establish and maintain uniform usage of geographic names throughout the federal govern ...

settled on "Big Sioux River" as the stream's name in 1931. The river was named after the Lakota people (Sioux Natives) which was known by them as Tehankasandata, or Thick Wooded River. The Big Sioux River rises in Roberts County, South Dakota on a low plateau known as the Coteau des Prairies and flows generally southwardly through

Grant Grant or Grants may refer to: Places *Grant County (disambiguation) Australia * Grant, Queensland, a locality in the Barcaldine Region, Queensland, Australia United Kingdom * Castle Grant United States * Grant, Alabama * Grant, Inyo County, ...

, Codington, Hamlin, Brookings, Moody, and Minnehaha counties, past the communities of Watertown, Castlewood, Bruce, Flandreau, Egan, Trent, Dell Rapids, and

Baltic Baltic may refer to: Peoples and languages *Baltic languages, a subfamily of Indo-European languages, including Lithuanian, Latvian and extinct Old Prussian *Balts (or Baltic peoples), ethnic groups speaking the Baltic languages and/or originatin ...

to Sioux Falls, where it passes over a

waterfall A waterfall is a point in a river or stream where water flows over a vertical drop or a series of steep drops. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf. Waterfalls can be formed in several ...

in Falls Park, which gives that city its name. Downstream of Sioux Falls and the community of Brandon, the Big Sioux defines the boundary between South Dakota and Iowa, flowing along the eastern borders of Lincoln and Union counties in South Dakota, and the western borders of

Lyon Lyon,, ; Occitan: ''Lion'', hist. ''Lionés'' also spelled in English as Lyons, is the third-largest city and second-largest metropolitan area of France. It is located at the confluence of the rivers Rhône and Saône, to the northwest of ...

Sioux The Sioux or Oceti Sakowin (; Dakota: /otʃʰeːtʰi ʃakoːwĩ/) are groups of Native American tribes and First Nations peoples in North America. The modern Sioux consist of two major divisions based on language divisions: the Dakota and ...

and

Plymouth Plymouth () is a port city status in the United Kingdom, city and unitary authority in South West England. It is located on the south coast of Devon, approximately south-west of Exeter and south-west of London. It is bordered by Cornwall to ...

counties in Iowa, past the communities of

Canton Canton may refer to: Administrative division terminology * Canton (administrative division), territorial/administrative division in some countries, notably Switzerland * Township (Canada), known as ''canton'' in Canadian French Arts and ente ...

, Fairview, Hudson,

Hawarden Hawarden (; cy, Penarlâg) is a village, community and electoral ward in Flintshire, Wales. It is part of the Deeside conurbation on the Wales-England border and is home to Hawarden Castle. In the 2011 census the ward of the same name ...

, North Sioux City, and Dakota Dunes in South Dakota and Beloit,

and

Akron Akron () is the fifth-largest city in the U.S. state of Ohio and is the county seat of Summit County. It is located on the western edge of the Glaciated Allegheny Plateau, about south of downtown Cleveland. As of the 2020 Census, the city ...

in Iowa. It joins the Missouri River from the north at

Sioux City, Iowa Sioux City () is a city in Woodbury and Plymouth counties in the northwestern part of the U.S. state of Iowa. The population was 85,797 in the 2020 census, making it the fourth-largest city in Iowa. The bulk of the city is in Woodbury County ...

DeLorme DeLorme is the producer of personal satellite tracking, messaging, and navigation technology. The company’s main product, ''inReach'', integrates GPS and satellite technologies. ''inReach'' provides the ability to send and receive text message ...

(1998). ''Iowa Atlas & Gazetteer''. Yarmouth, Maine: DeLorme.

(2001). ''South Dakota Atlas & Gazetteer''. Yarmouth, Maine: DeLorme. The Big Sioux River, at the

USGS The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...

station in

, has a mean annual discharge of approximately 3,793 cubic feet per second.

Tributaries

The Big Sioux River collects the Rock River from the northeast in Sioux County, Iowa. A minor

headwaters The headwaters of a river or stream is the farthest place in that river or stream from its estuary or downstream confluence with another river, as measured along the course of the river. It is also known as a river's source. Definition The ...

tributary of the Big Sioux in Grant County, South Dakota, is known as the Indian River. Broken Kettle Creek has its confluence with the Big Sioux in Plymouth County, Iowa.

Pollution

The Big Sioux is South Dakota's most populated river basin. Agriculture is the primary use of land along most of the river's course. To comply with the

Clean Water Act The Clean Water Act (CWA) is the primary federal law in the United States governing water pollution. Its objective is to restore and maintain the chemical, physical, and biological integrity of the nation's waters; recognizing the responsibiliti ...

, the state monitors water quality of its rivers. Most of the Big Sioux north of Sioux Falls was scored well in 2012. Portions near Lake Kampeska and between Willow and Stray Horse Creeks ( Codington and Hamlin counties) exceeded federally allowable levels of '' E. coli'' and fecal coliform bacteria. However, the Big Sioux south of Sioux Falls is much more polluted with ''E. coli'', fecal coliform, and

suspended solids Suspended solids refers to small solid particles which remain in suspension in water as a colloid or due to motion of the water. Suspended solids can be removed by sedimentation if their size or density is comparatively large, or by filtration. ...

. Several portions heavily restrict fishing or human contact, and swimming is banned.

Flood control

Between 1955 and 1961, an extensive

flood control Flood control methods are used to reduce or prevent the detrimental effects of flood waters."Flood Control", MSN Encarta, 2008 (see below: Further reading). Flood relief methods are used to reduce the effects of flood waters or high water level ...

system was constructed by the

U.S. Army Corps of Engineers , colors = , anniversaries = 16 June (Organization Day) , battles = , battles_label = Wars , website = , commander1 = ...

along the Big Sioux and some of its tributaries in Sioux Falls to protect the city from a

100-year flood A 100-year flood is a flood event that has a 1 in 100 chance (1% probability) of being equaled or exceeded in any given year. The 100-year flood is also referred to as the 1% flood, since its annual exceedance probability is 1%.Holmes, R.R., Jr. ...

event. Features of the system include of

levees A levee (), dike (American English), dyke (Commonwealth English), embankment, floodbank, or stop bank is a structure that is usually earthen and that often runs parallel to the course of a river in its floodplain or along low-lying coastli ...

, a

floodwall A flood wall (or floodwall) is a primarily vertical artificial barrier designed to temporarily contain the waters of a river or other waterway which may rise to unusual levels during seasonal or extreme weather events. Flood walls are mainly ...

in downtown, and a diversion channel with a dam at one end and a spillway at the other. The diversion channel connects two ends of the Big Sioux's natural loop around central Sioux Falls in an effort to channel floodwater away from the city. The levees then act to contain any floodwater either remaining in the natural channel or originating from Skunk Creek (whose mouth is downriver of the diversion dam).Jorgensen, Don. ''Sioux Falls diverts water to ease flooding'

KELO-TV KELO-TV (channel 11) is a television station in Sioux Falls, South Dakota, United States, affiliated with CBS and MyNetworkTV. The station is owned by Nexstar Media Group, and maintains studios on Phillips Avenue in downtown Sioux Falls; its tra ...

. March 15, 2010. (accessed April 19, 2010). Additionally, a greenway covers much of the river's floodplain in southern and eastern Sioux Falls, further mitigating any property damage from high water.

Flooding

The Big Sioux River experienced record-breaking flooding during the 2019 Midwestern U.S. floods. The Big Sioux River Flood Information System was used to model flooding during the March 2019 bomb cyclone event. The river overflowed its banks between September 12–15, 2019, flooding three blocks of

Dell Rapids, South Dakota Dell Rapids is a city in Minnehaha County, South Dakota, United States. The population was 3,996 at the 2020 census. It is known as "The Little City with the Big Attractions." The city took its name from the Dells of the Wisconsin River, which ...

, and damaging up to a dozen homes.

Interstate 90 Interstate 90 (I-90) is an east–west transcontinental freeway and the longest Interstate Highway in the United States at . It begins in Seattle, Washington, and travels through the Pacific Northwest, Mountain West, Great Plains, Midwest, and ...

was shut down between

Mitchell Mitchell may refer to: People *Mitchell (surname) *Mitchell (given name) Places Australia * Mitchell, Australian Capital Territory, a light-industrial estate * Mitchell, New South Wales, a suburb of Bathurst * Mitchell, Northern Territ ...

and Sioux Falls.

Tributaries

Pollution

Flood control

Flooding

See also

References

Further reading