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346:, which coated the valley with ash and filled it with successive mudflows. The result of the eruption was that many hillsides were stripped of forest, and as a result erosion has increased dramatically and the North Fork is now extremely laden with sediment. Previously, Spirit Lake was the source of the river, but eruptions blocked the outlet and Spirit Lake no longer drains directly into the North Fork; instead, a tunnel was excavated in 1985 to connect the lake with South Coldwater Creek, a tributary of the North Fork. Once a mature river, the North Fork has transformed into a
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The upper part of the North Fork Toutle River watershed was redirected to the crater of Mount St. Helens itself until 1982. The river's headstreams begin on a volcanic ash deposit roughly 3 miles (5 km) long and 200 feet (61 m) deep, which is the source of much of the excess sediment.
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450:"Summary of Drainage Basin and Channel Characteristics Toutle River System, Mount St. Helens, Washington, 1980–1985 Water Years"
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on the river in 1989 to prevent this sediment from traveling downstream and clogging the shipping channel of the
Columbia River.
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The results of the 1980 eruption were still prevalent in 1983, where the valley is seen still coated with volcanic ash
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of relatively young origin, and its valley floor is less than three decades old. The
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are marked and numbered on the relevant map quadrangles.
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The North Fork's watershed was severely affected by the
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in the United States. The river has its headwaters near
411:. United States Geological Survey. September 10, 1979
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532:Background about the river from USGS website
448:Meyer, D. F.; Dodge, J. E. (June 10, 2008).
137:Mount St. Helens National Volcanic Monument
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377:List of tributaries of the Columbia River
352:Toutle River Sediment Retention Structure
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63:of North Fork Toutle River in Washington
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562:Rivers of Skamania County, Washington
433:search using GNIS source coordinates.
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557:Rivers of Cowlitz County, Washington
372:List of rivers of Washington (state)
552:Braided rivers in the United States
452:. United States Geological Survey.
407:Geographic Names Information System
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16:River in Washington, United States
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501:United States Geological Survey.
344:1980 eruption of Mount St. Helens
293:302 sq mi (780 km)
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572:Gifford Pinchot National Forest
503:"United States Topographic Map"
323:. The largest tributary is the
141:Gifford Pinchot National Forest
429:Source elevation derived from
234: • coordinates
152: • coordinates
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111:Physical characteristics
547:Rivers of Washington (state)
356:U.S. Army Corps of Engineers
273: • elevation
195:3,449 ft (1,051 m)
191: • elevation
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217: • location
132: • location
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402:"North Fork Toutle River"
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301:North Fork Toutle River
285:39 mi (63 km)
22:North Fork Toutle River
482:Cite journal requires
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303:is a tributary of the
256:46.32778°N 122.71667°W
174:46.26500°N 122.16083°W
33:Sediment retention dam
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261:46.32778; -122.71667
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507:. Retrieved
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475:cite journal
463:. Retrieved
431:Google Earth
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413:. Retrieved
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305:Toutle River
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210:Toutle River
516:River miles
509:January 27,
505:. TopoQuest
465:January 27,
415:January 27,
325:Green River
313:Spirit Lake
259: /
247:122°43′00″W
177: /
165:122°09′39″W
124:Spirit Lake
541:Categories
383:References
309:Washington
290:Basin size
244:46°19′40″N
162:46°15′54″N
91:Washington
366:See also
101:Skamania
72:Location
105:Cowlitz
77:Country
409:(GNIS)
329:Toutle
282:Length
223:Toutle
120:Source
97:County
221:near
205:Mouth
87:State
61:mouth
511:2013
488:help
467:2013
417:2013
299:The
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Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
