Columbia (river, Canada and the United States)
Columbia, river, c.1,210 mi (1,950 km) long, rising in Columbia Lake, SE British Columbia, Canada. It flows first NW in the Rocky Mt. Trench, then hooks sharply about the Selkirk Mts. to flow S through Upper Arrow Lake and Lower Arrow Lake and receive the Kootenai River (spelled Kootenay in Canada) before entering the United States after a course of 465 mi (748 km). It continues S through Washington and just below the mouth of the Spokane River is forced by lava beds to make a great bend westward before veering south again, running the while entrenched in a narrow valley through the Columbia Plateau. Its chief tributary, the Snake River, joins it just before it turns west again. The Columbia then forms part of the Washington-Oregon border before entering the Pacific Ocean through a wide estuary W of Portland, Oreg.
The Columbia River has created regal gorges by cutting through the Cascades and the Coast Ranges; it is fed by the Cowlitz and Willamette rivers, which drain the Puget trough between those ranges. Grand Coulee, now a reservoir in the Columbia basin project, was a former stream channel of the Columbia River. It was created during the last ice age when the Columbia's course was blocked by ice, forcing it to cut a new channel through the Columbia Plateau. When the ice receded the river resumed its former channel.
Settlement and Human Impact
The Columbia River, commanding one of the great drainage basins of North America (c.259,000 sq mi/670,800 sq km), was visited by Robert Gray, an American explorer, in 1792 and is named for his vessel, the Columbia. It was entered by a British naval officer, William R. Broughton, later the same year. Long before this time Native Americans were fishing salmon from the river; today fish are still caught there, but heavy settlement along the river and its tributaries, the construction of dams, and human use have reduced the salmon runs.
The first whites to arrive overland were the members of the Lewis and Clark expedition and the fur traders (notably David Thompson of the North West Company and the founders of Astoria). The river was the focus of the American settlement that created Oregon, and the river was itself sometimes called the Oregon River or the River of the West. Irrigation was begun early, and some tributaries were used to water cropland and orchards, as in the valleys of the Wenatchee and Yakima rivers.
After 1932 plans gradually developed to use the Columbia River to its ultimate possibility, and the Columbia basin project was established. Its purpose is to establish flood control, which would alleviate the destruction seen in the Columbia's greatest flood, that of 1894, and somewhat lesser but damaging floods, such as that of 1948; to improve navigation; to extend irrigation in order to make optimum use of the water of the Columbia and its tributaries; and to produce hydroelectric power to supply the Pacific Northwest.
There are six federal and five nonfederal dams on the Columbia River. Grand Coulee Dam (the key unit of the Columbia basin project) and Chief Joseph Dam, on the river's upper course, provide power, flood control, and irrigation. Priest Rapids, Wanapum, Rock Island, Rocky Reaches, and Wells dams are on the middle course; all are among the largest nonfederal hydroelectric facilities in the United States. Bonneville, The Dalles, John Day, and McNary dams, on the lower course, were designed as power, flood control, and navigation projects; these dams provide a 328-mi (528-km) slack-water navigation channel up the Columbia River from the Pacific Ocean to the Snake River. With these federal projects and nonfederal dams on the Columbia, hydroelectric plants on the river have a potential generating capacity of about 21 million kW. The development of hydroelectric power has had a significant effect on the economic pattern of the Pacific Northwest.
See J. V. Krutilla, The Columbia River Treaty; The Economics of an International River Basin Development (1967); J. E. Allen and M. Burns, Cataclysms of the Columbia (1987); W. Dietrich, The Great Columbia River (1995); R. White, The Organic Machine (1995).