The Willamette River is a major tributary of the Columbia River. The main stem is 187 miles long, lying entirely in northwestern Oregon. The river’s drainage basin was significantly modified by the Missoula Floods at the end of the most recent ice age.
About Willamette River in brief
The Willamette River is a major tributary of the Columbia River. The main stem is 187 miles long, lying entirely in northwestern Oregon in the United States. The river’s drainage basin was significantly modified by the Missoula Floods at the end of the most recent ice age. Since 1900, more than 15 large dams and many smaller ones have been built in the drainage basin, 13 of which are operated by the U.S. Army Corps of Engineers. Part of the Willamettes Floodplain was established as a National Natural Landmark in 1987 and the river was named as one of 14 American Heritage Rivers in 1998. The upper tributaries of the willamette originate in the mountains south and southeast of Eugene, Oregon. It enters the Columbia about 101 miles from the larger river’s mouth on the Pacific Ocean. The channel forms the primary navigational conduit for Portland’s harbor and riverside industrial areas. The smaller Multnomah Channel, a distributary, is 21 miles long, about 600 feet wide, and 40 feet deep. It ends about 14.5 miles further downstream on the Columbia, near St. Helens in Columbia County. It is roughly 103.5 feet to 43 feet in length on tandem-maintained navigation on theColumbia River. Between the 1850s and the 1960s, straightening and flood control projects, as well as agricultural and urban encroachment, cut the river’s length by 40 percent. The Willamettes are two major highways that follow the river for its entire length. Communities along the main stem include Springfield and Eugene in Eugene County; Harrisburg in Linn County; Benton County; Corvallis in Corvalls County; and Albany in Benton and Benton counties.
It was an important transportation route in the 19th-century, although WillAmette Falls, just upstream from Portland, was a major barrier to boat traffic. In the 21st century, major highways follow the mainstem on approximately 30 different bridges. More than half a dozen bridges not open to motorized vehicles provide separate crossings for bicycles and pedestrians, and several others are exclusively for rail traffic. There are also ferries that convey cars, trucks, motorcycles, bicycles, and pedestrians across the river in the Will amette Valley for a fare and provided river conditions permit. The waterway supports 60 fish species, including many species of salmon and trout; this is despite the dams, other alterations, and pollution. The river is one of North America’s most fertile agricultural regions in North America, and was thus the destination of many 19th century pioneers traveling west along the Oregon Trail. It’s one of the three main branches of Oregon Route 99. It flows northward between the Oregon Coast Range and the Cascade Range, and it’s a basin that contains two-thirds of Oregon’s population, including the state capital, Salem, and the state’s largest city, Portland, which surrounds the Will Amette’s mouth at the Columbia.
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This page is based on the article Willamette River published in Wikipedia (as of Dec. 03, 2020) and was automatically summarized using artificial intelligence.