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.