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Encyclopedia Britannica - Main :: CLI-COM |
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COLUMBIA RIVER , a stream of the north-west United States and south-west Canada, about 939 M. in length, draining a basin of about 250,000 sq. m., of which 38,395 are in British Columbia; some 1o5,000 sq. m. belong to the valley of the Snake and 11,700 to that of the Willamette. The source of the river is partly in the Yellowstone country, partly near the Titon peaks, and partly in the pine-clad mountains of British Columbia. Some American geographers regard the head as that of the Clark
great
Clark
Helena
Great
east
After the confluence of the Snake with the Columbia the greater river turns west toward the Pacific. Throughout its course to this point it may be said that the Columbia has no flood plain; everywhere it is cutting its bed; almost every-where it is characterized by canyons, although above the Spokane the valley is much broken down and there is considerable timbered and fertile bench land. Below the Spokane the canyon becomes more steep and rugged. From the mouth of the Okanogan to Priests Rapids extends a superb canyon, with precipitous walls of black columnar basalt loon to 3000 ft. in height. The finest portion is below the Rock Island Rapids. In this part of its course, along the Cascade range in the Great Plain and at its passage of the range westward, rapids and cascades particularly obstruct the imperfectly opened bed. In the lower Columbia, navigation is first interrupted 16o m. from the mouth at the Cascades, a narrow gorge across the Cascade range 4.5 m. long, where the river falls 24 ft. in 2500; the rapids are evaded by a canal constructed (18781896) by the Federal government, and by a portage
series of falls, rapids and rock obstructions extending some 12 M. and ending at Celilo, 115 M. below Wallula, with a fall of 20 ft. There are also impediments just below the mouth of the Snake; others in the lower course of this river below Riparia; and almost continuous obstructions in the Columbia above Priests Rapids. The commerce of the Columbia is very important, especially that from Portland
Astoria
interest
The Columbia is one of the greatest salmon streams of the world (see OREGON). The tonnage of deep-sea vessels in and out over the bar at the river's mouth from 18901899 was 9,423,637 tons. From 18721899 the United States government expended for improvement of the Snake and Columbia $6,925,649. The mouth of the latter is the only deep-water harbour between San Francisco and Cape Flattery (700 m.), and the only fresh water harbour of the Pacific coast. To facilitate its entrance, which, owing to bars, tides, winds, and the great discharge of the river, has always been difficult, a great jetty has been constructed (18851895, later enlarged) to scour the bars. It was about 4.5 miles long, and in 1903 work
Astoria
Portland
In 1792, and possibly also in 1788, the river mouth was entered by Captain Robert Gray (17551806) of Boston, Mass., who named the river after his own vessel. " Columbia," which name has wholly supplanted the earlier name, " Oregon." In 18041805 the river was explored by Meriwether Lewis and William Clark. Upon these discoveries the United States primarily based its claim to the territory now embraced in the states of Oregon and Washington. End of Article: COLUMBIA RIVER If you wish, you can link directly to this article.
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