Cheyenne River

Course

Formed by the confluence of Antelope Creek and Dry Fork Creek in Wyoming, it rises in northeastern Wyoming in the Thunder Basin National Grassland in Converse County. It flows east into South Dakota, passes Edgemont, and skirts the southern end of the Black Hills, passing through Angostura Reservoir. On the east side of the Black Hills, it flows northeast, past Oral, the Buffalo Gap National Grassland, and along the northwestern boundary of the Pine Ridge Indian Reservation and Badlands National Park. It is joined by Rapid Creek, passes Wasta and is joined by the Belle Fourche River in eastern Meade County, after which it flows ENE along the southern boundary of the Cheyenne River Indian Reservation. Near the town of Cherry Creek, it is joined by Cherry Creek and flows into Missouri at Lake Oahe, approximately 32 mi (50 km) NNW of Pierre, South Dakota, with the lower 35 mi (56 km) of the river forming an arm of Lake Oahe.

The Belle Fourche River is the largest tributary of the Cheyenne. Rapid, Sulphur, Plum, Cherry, and Owl Creeks are important other tributaries of the Belle Fourche-Cheyenne. Snowmelt from the Black Hills provides the major source of river water. Because of the proximity to the Black Hills and its mining industry, the Cheyenne historically picked up large quantities of zinc, arsenic, and cyanide. Those pollutants are no longer a major threat due to water quality regulations. The Cheyenne River is still higher in dissolved mineral content than any other South Dakota major river.

Cheyenne Watershed

The Cheyenne watershed is part of the Missouri River watershed and spans the Mountain West and Great Plains states of northeastern Wyoming, southwestern and south central South Dakota, as well as small areas of northwestern Nebraska, and southeastern Montana. As of 2001, the Cheyenne watershed was primarily grassland (62.8%), followed by shrubland (16.3%) and forest cover (11.9%). The primary population centers include Rapid City, South Dakota and Gillette, Wyoming.

With a population of nearly 4.5 million in these states, water use was an average of 5254 e6gal/d in 2010. This amounts to approximately 1170 gal per person per day. A total of 1855 e3acre-ft are stored in 9 lakes and reservoirs in the Cheyenne watershed.

Sedimentation is a major water quality concern for the Cheyenne watershed, potentially resulting in reduced storage capacity for reservoirs. Major water issues in the Cheyenne, reflect those of the larger Missouri River basin and stem from anticipated effects from a warming climate.

Industrial use

Demand for water from agriculture for irrigation, greater threats to viable habitat for endangered species and wildlife are large concerns directly related to increasing temperatures and evapotranspiration. Water companies are also concerned about "water delivery" in response to shifting runoff periods. Similarly, power companies are concerned about climate effects on hydropower generation.

As of November 2019, TC Energy was applying for permits in the state to tap the Cheyenne River to use water for the construction of Phase 4 of the Keystone pipeline, including camp construction to house transient construction workers.

References

References

1. "USGS Surface Water data for South Dakota: USGS Surface-Water Annual Statistics".
2. (2011). "New Lakota Dictionary". Lakota Language Consortium.
3. (1923). "The life and papers of Frederick Bates". Missouri Historical Society.
4. Federal Writers' Project. (1940). "South Dakota place-names, v.3". University of South Dakota.
5. "Archived copy".
6. (2001). "The Geography of South Dakota". The Center for Western Studies – [[Augustana College (South Dakota).
7. "USGS EDNA-Derived Watershed Characteristics".
8. "US Census Data 2015".
9. "Estimated Use of Water in the United States in 2010".
10. "US Bureau of Reclamation Snowpack and Reservoir Levels".
11. (March 2016). "Reclamation: Managing Water in the West Chapter 6: Missouri River Basin". US Department of the Interior.
12. STEPHEN GROVES. (2019-11-01). "South Dakota Keystone XL opponents point to N. Dakota spill". The Associated Press.