Willamette River
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| Willamette River | |
|---|---|
| | |
| Origin | Coastal Range and Cascade Range |
| Mouth | Columbia River |
| Length | 187 mi (301 km) |
| Source elevation | 450 ft (137.2 m) |
| Mouth elevation | sea level plus river stage |
| Avg. discharge | December: 67800 ft3/s (1920 m3/s) August: 8480 ft3/s (240 m3/s)<ref>USGS Surface-Water Monthly Statistics. USGS. Retrieved on 2006-8-20.</ref> |
| Basin area | 11100 mi2 (28700 km2)<ref name="nwis">National Water Information System. USGS. Retrieved on 2006-8-20.</ref> |
The Willamette River (pronounced wil-LAM-met, or [wɪ.læ.mɨt] in IPA, with the accent on the second syllable) is a tributary of the Columbia River, 187 mi (301 km) long<ref> 187 miles is to the Coast Fork and Middle Fork junction. Including the longest tributary, the Willamette is approximately 240 mi (386 km).</ref>, in northwestern Oregon in the United States. Flowing northward between the Coastal Range and Cascade Range, the river and its tributaries form a basin called the Willamette Valley containing 68% of Oregon's population,<ref>Willamette Basin Alternative Futures Analysis (PDF). U.S. Enviornmental Protection Agency (August, 2002). Retrieved on 2006-11-16.</ref> including its largest city Portland, which sits along both sides of the river near its mouth on the Columbia. Its lush valley is fed by prolific rainfall on the western side of the Cascades, forming one of the most fertile agricultural regions of North America that was the destination for many if not most of the emigrants along the Oregon Trail. The river was an important transportation route throughout much of the early history of the state, furnishing a means of conveying the vast timber and agricultural resources of the state to the outside world.
Part of the river's floodplain (the Willamette Floodplain) was established as a National Natural Landmark in 1987; ten years later the river was named as one of ten national American Heritage Rivers.
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[edit] Description
Image:Willamette River.jpg The Willamette rises in three separate forks in the mountains south and southeast of Eugene, at the southern end of the Willamette Valley. The Middle Fork and North Fork rise on the western side of the Cascades between Three Sisters south to Diamond Peak, with the Middle Fork receiving the North Fork northwest of Oakridge and flowing northwest through the mountains to the southern end of the Willamette Valley. The Coast Fork rises in the lower mountains south of Cottage Grove, flowing north to join the Middle Fork 2 mi (3.2 km) southeast of Eugene.
From Eugene, the combined river flows NNW across the plain of the southern Willamette Valley to Corvallis, then follows a zigzag course past Albany and around the isolated hills in the central valley, passing west of downtown Salem. From Salem it flows north in a meandering course across the northwest plain of the valley, reaching the hills at Newberg, where it turns sharply ENE along the hills, passing through an opening in the hills at Oregon City, the location of the Willamette Falls and the head of navigation. From Oregon City it flows northwest, past Lake Oswego and Milwaukie on the south edge of Portland, then passing between east and west Portland, where it is spanned by a series of urban bridges. Downstream of downtown Portland it flows northwest through the industrial port area of Portland Harbor, then splitting into two channels around Sauvie Island, both of which hook around to enter the Columbia from the west, with the main channel entering on the north edge of Portland and the smaller Multnomah Channel entering approximately 15 mi (24 km) NNW at St. Helens.
The river's many tributaries drain the surrounding valley as well as portions of the Cascades and the Coastal Range. Downstream from the confluence of its forks, it is joined by McKenzie on the north side of Eugene, and by the Long Tom River from the southwest approximately 10 mi (16 km) south of Corvallis. It is joined by the Marys from the west at Corvallis, and the Calapooia from the southeast 5 mi (8 km) northeast of Corvallis, and It is joined by the Santiam from the east and the Luckiamute from the west within 1 mi (1.6 km) of each other approximately 5 mi (8 km) north of Albany. It is joined by the Yamhill from the west at Dayton, by the Molalla from the southeast near Canby, by the Tualatin from the west at West Linn, and by the Clackamas from the southeast at Gladstone.
The river forms part of the boundary of the following counties: Benton, Linn, Polk, Marion, Yamhill and Clackamas. Tributaries of the Willamette River also drain some or all of Lane, Washington and Multnomah counties.
Although riverboats navigated the upstream part of the Willamette into the first decades of the 20th century, currently there is little commercial traffic on the river above the Willamette Falls. The Willamette Falls Locks allow boat traffic, primarily recreational vessels, around the falls. The river is crossed by three ferries along its route in the Willamette Valley. The three ferries are located at Buena Vista, Wheatland, and Canby. The only locks on the river are located at Oregon City. For information on canoeing and kayaking on the Willamette River, see "Canoe and Kayak Routes of Northwest Oregon," by Philip N. Jones.
The Willamette River is prone to periodic floods. Notable floods include events in 1861 (which destroyed Linn City, Oregon), 1899, 1964, and the Willamette Valley Flood of 1996.
The river below Willamette Falls is subject to semidiurnal tides caused by the Pacific Ocean, but also with the effects of dams on the Columbia River and Willamette river basin which are regulated for hydroelectric power generation. Reverse flow has been observed as far upstream as Ross Island (river mile 15).<ref>Caldwell, James M.; Micelis C. Doyle. Sediment Oxygen Demand in the Lower Willamette River, Oregon, 1994 (PDF) pp. 4. Oregon Department of Envoirnmental Quality. Retrieved on 2006-11-16.</ref>
The lower river flow rate varies considerably by season and due to weather. Warm winter rains, for example, cause extensive mountain snow melt which significantly raises the river level and flow rate. The Willamette Valley Flood of 1996 was an extreme combination of saturated ground, snow melt and heavy rain: The maximum flow rate is not known, however 283,000 cubic feet per second (8010 m³/s) was estimated on January 181974 at river gage 23.84 feet (7.27 m). The peak river gage on February 91996 was 27.74 feet (8.46 m). Flood stage is 18.0 feet (5.5 m). The other extreme occurred during a drought on July 101978 at 4,200 ft³/s (120 m³/s).<ref name="nwis" /> The Willamette's mean discharge rate is approximately 32,000 cubic feet per second.[1]
[edit] Environmental issues
The Portland Harbor section of the Willamette River between downtown Portland and its terminus at the Columbia River is heavily polluted from years of industrial development of the river and its banks. Historical and current activities have included shipbuilding, creosote manufacture, and transfer and storage of petroleum products. State studies in the 1990s identified a wide variety of pollutants in the river bottom, including heavy metals, polychlorinated biphenyls (PCBs), and pesticides. As a result of these studies, this section of the river was designated a Superfund site in 2000, involving the federal Environmental Protection Agency in cleanup of the river bottom.<ref>Portland Harbor Superfund Site. Oregon Department of Environmental Quality. Retrieved on 2006-11-16.</ref> As of 2005, cleanup and containment of the pollutants is underway and is expected to be completed by 2006.
[edit] Crossings of the Willamette
Many bridges and a few ferries span the Willamette River, including the following (from south to north)
| River mile | Nearby city | Name | Year opened | Used by |
| 163 | Junction City | Union Pacific | Unknown | Union Pacific Railroad line (Amtrak?) |
| 163 | Junction City | Portland & Western | Unknown | Portland and Western Railroad (formerly Oregon Electric Railway) |
| 161.2 | Harrisburg | Oregon 99W | Unknown | Route 99W |
| 132 | Corvallis | Corvallis Bypass Bridge | 1992 | U.S. Highway 20 Bypass |
| 131.5 | Corvallis | Van Buren Street Bridge | 1913 | Van Buren Street |
| 131.5 | Corvallis | Harrison Street Bridge | Unknown | Harrison Street |
| 120.1 | Albany | Ellsworth Street Bridge | 1926 | Ellsworth Street |
| 120 | Albany | Lyon Street Bridge | 1968(?) | Lyon Street |
| 119.7 | Albany | Toledo District Willamette Bridge | Unknown | Portland and Western Railroad/Toledo District |
| 106 | Buena Vista Ferry | 1851 | Buena Vista Road | |
| 97.1 | Independence | Independence Street Bridge | 1950 | Independence Street |
| 84.5 | Salem | Center Street Bridge | 1918 | Center Street/Route 22 |
| 84.4 | Salem | Marion Street Bridge | 1952 | Marion Street/Route 22 |
| 84.3 | Salem | Salem railroad bridge | Unknown | Abandoned Black Rock Rail Line |
| 72.0 | Wheatland Ferry | 1844 | Wheatland Road | |
| 48.3 | Newberg | Oregon Route 219 bridge | Unknown | Route 219 |
| 38.5 | Wilsonville | Portland & Western Railroad bridge | Unknown | Portland & Western Railroad (formerly Oregon Electric |
| 38.3 | Wilsonville | Boone Bridge | 1954 | Interstate 5 |
| 33.0 | Canby | Canby Ferry | 1911 | |
| 26.0 | Oregon City | Oregon City Bridge | 1922 | Oregon Route 43 |
| 25.0 | Oregon City | Abernethy Bridge | 1970 | Interstate 205 |
| 20.0 | Lake Oswego | Lake Oswego Railroad Bridge | 1910 | |
| 16.5 | Portland (Sellwood) | Sellwood Bridge | 1925 | Tacoma Street |
| 14.0 | Portland | Ross Island Bridge | 1926 | U.S. Highway 26/Powell Blvd. |
| 13.5 | Portland | Marquam Bridge | 1966 | Interstate 5 |
| 13.1 | Portland (Downtown) | Hawthorne Bridge | 1910 | Hawthorne Blvd. |
| 12.8 | Portland (Downtown) | Morrison Bridge | 1958 | Morrison Street |
| 12.4 | Portland (Old Town Chinatown) | Burnside Bridge | 1926 | Burnside Street |
| 12.1 | Portland (Old Town Chinatown) | Steel Bridge | 1912 | Union Pacific Railroad, Amtrak, Glisan Street (formerly Route 99W), MAX Light Rail |
| 11.7 | Portland | Broadway | 1913 | Broadway |
| 11.1 | Portland | Fremont Bridge | 1973 | Interstate 405 |
| 7.0 | Portland (St. Johns) | Burlington Northern Railroad Bridge 5.1 | 1908 | BNSF Railway |
| 5.8 | Portland (St. Johns) | St. Johns Bridge | 1931 | U.S. Highway 30 Bypass/Philadelphia Avenue |
[edit] See also
[edit] References
<references />
[edit] External links
- Portland Harbor DEQ cleanup - Oregon state Department of Environmental Quality
- Willamette Riverkeeper - Working to protect and restore the Willamette Riverde:Willamette River
