The Columbia Basin, the drainage basin of the Columbia River, occupies a large area–about 673,396 square kilometres (260 square miles)—of the Pacific Northwest region of North America.[1] In common usage, the term often refers to a smaller area, generally the portion of the drainage basin that lies within eastern Washington.[1]
Usage of the term "Columbia Basin" in British Columbia generally refers only to the immediate basins of the Columbia and Kootenay Rivers and excludes that of the Okanagan, Kettle and Similkameen Rivers.
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Complete watershed
The Columbia Basin includes the southeastern portion of the Canadian province of British Columbia, most of the U.S. states of Idaho, Oregon, and Washington, the western part of Montana, and very small portions of Nevada, Utah, and Wyoming. The south and southeastern drainage divide borders the interior drainage of the northern Great Basin. To the northeast the region borders the basins of the Saskatchewan River (Hudson Bay) and the MacKenzie River (Beaufort Sea), and to the northwest the basin of the Fraser River. The Columbia Basin extends from the Rocky Mountains in the east through the Cascade Range to the Columbia River's outflow at the Pacific Ocean in the west.
Common usage
Residents of the area surrounding the confluence of the Columbia and Snake rivers—a region centering on the Tri-Cities, Washington metropolitan area—use the term "Columbia Basin" to refer to their own, much smaller region. This usage is roughly synonymous with the Columbia Plateau or roughly equivalent to the relatively unforested area bounded by the Cascades, Blue, Wallowa, and Rocky mountain ranges and the Okanagan Highland. This sense of the term Columbia Basin has expanded from its early focus on the land irrigated by Grand Coulee Dam and the Columbia Basin Project to include other irrigation districts such as the Yakima and Walla Walla valleys.[2] At its center is the Pasco Basin, an area roughly double the size of, and fully containing, the Hanford Site.[1]
See also
References
- ^ a b c Floyd, Ben, et al. "Glossary". (1998) Hanford Reach Protection and Management Program Interim Action Plan. Prosser, Washington: Benton County Planning Department.
- ^ Meinig, D.W. (1995) [1968]. The Great Columbia Plain (Weyerhaeuser Environmental Classic edition ed.). University of Washington Press. pp. 4, 482. ISBN 0-295-97485-0.
External links
- Geology of Washington - Columbia Basin, Washington State Department of Natural Resources
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