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The '''Willamette River''' (pronounced {{IPA-en|wɨˈlæmɨt||WillametteRiver-English.ogg}}) is a major [[tributary]] of the [[Columbia River]], accounting for 12 to 15 percent of the Columbia's flow. The Willamette's [[main stem]] is {{convert|187|mi|km}} long, lying entirely in northwestern Oregon in the United States. Flowing northward between the [[Oregon Coast Range]] and the [[Cascade Range]], the river and its tributaries form the [[Willamette Valley]], a basin that contains two-thirds of Oregon's population, including the state capital, [[Salem, Oregon|Salem]], and the state's largest city, [[Portland, Oregon|Portland]]. Portland surrounds the Willamette near the river's [[River delta|mouth]] at the Columbia.
The '''Willamette River''' (pronounced {{IPA-en|wɨˈlæmɨt||WillametteRiver-English.ogg}}) is a major [[tributary]] of the [[Columbia River]], accounting for 12 to 15 percent of the Columbia's flow. The Willamette's [[main stem]] is {{convert|187|mi|km}} long, lying entirely in northwestern Oregon in the United States. Flowing northward between the [[Oregon Coast Range]] and the [[Cascade Range]], the river and its tributaries form the [[Willamette Valley]], a basin that contains two-thirds of Oregon's population, including the state capital, [[Salem, Oregon|Salem]], and the state's largest city, [[Portland, Oregon|Portland]]. Portland surrounds the Willamette's [[River delta|mouth]] at the Columbia.


Formed originally by [[plate tectonics]] about 35 million years ago and subsequently altered by [[volcanism]] and erosion, the river basin was significantly modified by the [[Missoula Floods]] at the end of the most recent [[Last glacial period|ice age]]. Humans began living in the watershed over 10,000 years ago. Many tribal villages once lay along the lower river and the area around its confluence with the Columbia, and some indigenous peoples were spread throughout the upper reaches of the basin as well.
Formed originally by [[plate tectonics]] about 35 million years ago and subsequently altered by [[volcanism]] and erosion, the river basin was significantly modified by the [[Missoula Floods]] at the end of the most recent [[Last glacial period|ice age]]. Humans began living in the watershed over 10,000 years ago. Many tribal villages once lay along the lower river and the area around its confluence with the Columbia, and some indigenous peoples were spread throughout the upper reaches of the basin as well.


Rich with sediments deposited by flooding and fed by prolific rainfall on the western side of the Cascades, the Willamette Valley is one of the most fertile agricultural regions of [[North America]], and was thus the destination of many 19th-century pioneers traveling west along the [[Oregon Trail]]. The river was an important transportation route during [[Oregon pioneer history|this time]], although [[Willamette Falls]], just above Portland, was a major barrier to boat traffic. In the 21st century, major highways follow the river or cross it on one of more than 50 bridges.
Rich with sediments deposited by flooding and fed by prolific rainfall on the western side of the Cascades, the Willamette Valley is one of the most fertile agricultural regions of [[North America]], and was thus the destination of many 19th-century pioneers traveling west along the [[Oregon Trail]]. The river was an important transportation route during [[Oregon pioneer history|this time]], although [[Willamette Falls]], just upriver from Portland, was a major barrier to boat traffic. In the 21st century, major highways follow the river. Roads cross it on more than 50 bridges.


Since 1900, more than 15 major dams and many smaller ones have been built in the Willamette's drainage basin, and 13 of them are managed by the [[United States Army Corps of Engineers]] (USACE). The dams are used primarily to produce [[hydropower]], to store water for [[irrigation]], and to divert water into deeper, narrower channels in order to prevent flooding. Despite the dams, other alterations, and pollution (especially on its lower reaches), the river and its tributaries support 60 fish species, including many species of [[salmon]] and [[trout]]. Part of the river's [[floodplain]] (the [[Willamette Floodplain]]) was established as a [[National Natural Landmark]] in 1987; 10 years later the river was named as one of 10 national [[American Heritage Rivers]].
Since 1900, more than 15 large dams and many smaller ones have been built in the Willamette's drainage basin, and 13 of them are managed by the [[United States Army Corps of Engineers]] (USACE). The dams are used primarily to produce [[hydropower]], to store water for [[irrigation]], and to divert water into deeper, narrower channels in order to prevent flooding. Despite the dams, other alterations, and pollution (especially on its lower reaches), the river and its tributaries support 60 fish species, including many species of [[salmon]] and [[trout]]. Part of the [[Willamette Floodplain]] was established as a [[National Natural Landmark]] in 1987; 10 years later the river was named as one of 10 national [[American Heritage Rivers]].


==Course==
==Course==

Revision as of 20:27, 6 August 2011

Template:Geobox

The Willamette River (pronounced /wɨˈlæmɨt/ ⓘ) is a major tributary of the Columbia River, accounting for 12 to 15 percent of the Columbia's flow. The Willamette's main stem is 187 miles (301 km) long, lying entirely in northwestern Oregon in the United States. Flowing northward between the Oregon Coast Range and the Cascade Range, the river and its tributaries form the Willamette Valley, a basin that contains two-thirds of Oregon's population, including the state capital, Salem, and the state's largest city, Portland. Portland surrounds the Willamette's mouth at the Columbia.

Formed originally by plate tectonics about 35 million years ago and subsequently altered by volcanism and erosion, the river basin was significantly modified by the Missoula Floods at the end of the most recent ice age. Humans began living in the watershed over 10,000 years ago. Many tribal villages once lay along the lower river and the area around its confluence with the Columbia, and some indigenous peoples were spread throughout the upper reaches of the basin as well.

Rich with sediments deposited by flooding and fed by prolific rainfall on the western side of the Cascades, the Willamette Valley is one of the most fertile agricultural regions of North America, and was thus the destination of many 19th-century pioneers traveling west along the Oregon Trail. The river was an important transportation route during this time, although Willamette Falls, just upriver from Portland, was a major barrier to boat traffic. In the 21st century, major highways follow the river. Roads cross it on more than 50 bridges.

Since 1900, more than 15 large dams and many smaller ones have been built in the Willamette's drainage basin, and 13 of them are managed by the United States Army Corps of Engineers (USACE). The dams are used primarily to produce hydropower, to store water for irrigation, and to divert water into deeper, narrower channels in order to prevent flooding. Despite the dams, other alterations, and pollution (especially on its lower reaches), the river and its tributaries support 60 fish species, including many species of salmon and trout. Part of the Willamette Floodplain was established as a National Natural Landmark in 1987; 10 years later the river was named as one of 10 national American Heritage Rivers.

Course

Main article: Course of the Willamette River

The upper tributaries of the Willamette originate in mountains south and southeast of Eugene and Springfield. Formed by the confluence of the Middle Fork Willamette River and Coast Fork Willamette River near Springfield, the main stem meanders generally north for 187 miles (301 km) to the Columbia. The river's two most significant course deviations occur at Newberg, where it turns sharply east, and about 18 miles (29 km) downriver from Newberg, where it turns north again. Near its mouth north of downtown Portland, the river splits into two channels that flow around Sauvie Island. The main channel enters the Columbia about 101 miles (163 km) from the larger stream's mouth on the Pacific Ocean. The smaller Multnomah Channel, a distributary, enters the Columbia about 14.5 miles (23.3 km) further downstream near St. Helens in Columbia County.[1][2]

Major highways that follow the river for its entire length are Interstate 5 and U.S. Route 99. Communities along the main stem include Springfield and Eugene in Lane County; Harrisburg in Linn County; Corvallis in Benton County; Albany in Linn and Benton counties; Salem in Marion County; Newberg in Yamhill County; Oregon City, West Linn, Milwaukie, and Lake Oswego in Clackamas County, and Portland in Multnomah and Washington counties. Significant tributaries from source to mouth include the Middle and Coast forks and the McKenzie, Long Tom, Marys, Calapooia, Santiam, Luckiamute, Yamhill, Molalla, Tualatin, and Clackamas rivers.[1][2]

Arising at 438 feet (134 m) above sea level, the main stem loses 428 feet (130 m) in elevation between source and mouth, or about 2.3 feet per mile (1.1 m per km).[3] The gradient is slightly steeper from the source to Albany than it is from Albany to Oregon City.[4] At Willamette Falls, between West Linn and Oregon City, the river plunges about 40 feet (12 m).[4] For the rest of its course, the river is extremely low-gradient and is influenced by Pacific Ocean tidal effects from the Columbia.[4] The main stem of the Willamette varies in width from about 330 to 660 feet (100 to 200 m).[4]

Discharge

Main article: Course of the Willamette River § Discharge

With an average flow at the mouth of about 37,400 cubic feet per second (1,060 m3/s), the Willamette ranks 19th in volume among U.S. rivers[5] and contributes 12 to 15 percent of the total flow of the Columbia River.[6] The Willamette's flow varies considerably season to season, averaging about 8,200 cubic feet per second (230 m3/s) in August (lower than in any other month) and more than 79,000 cubic feet per second (2,200 m3/s) in December.[4]

The Willamette River at Harrisburg

The United States Geological Survey (USGS) operates four stream gauges along the river, at Harrisburg, Albany, Salem, and Portland. The average discharge at the lowermost gauge, near the Morrison Bridge in Portland, was 32,950 cubic feet per second (933 m3/s) between 1972 and 2009. Located at river mile (RM) 12.8 or river kilometer (RK) 20.6, the gauge measures the flow from an area of 11,200 square miles (29,000 km2), roughly 97 percent of the Willamette basin.[7] The maximum flow estimated at this station was 420,000 cubic feet per second (11,893 m3/s) on February 9, 1996, during the Willamette Valley Flood of 1996, and the minimum was 4,200 cubic feet per second (120 m3/s) on July 10, 1978.[7] According to the USACE, the highest recorded flow of 635,000 cubic feet per second (18,000 m3/s) for the Willamette at Portland occurred during a flood in 1861. This and many other large flows preceded the Flood Control Act of 1936 and dam construction on the Willamette's major tributaries.[8]

The river below Willamette Falls, 26.5 miles (42.6 km) from the mouth, is affected by semidiurnal tides,[9] and gauges have detected reverse flows above Ross Island at RM 15 (RK 24).[10] The National Weather Service issues tide forecasts for the river at the Morrison Bridge.[11]

Geology

The Willamette River basin was created primarily by plate tectonics and volcanism and it was altered by erosion and sedimentation, including some related to enormous glacial floods as recent as 13,000 years ago.[12] The initial trough-like configuration was created about 35 million years ago[6] as a forearc basin while the Pacific Plate subducted beneath the North American Plate.[12] Marine deposits on top of older volcanics underlie the valley, which was initially part of the continental shelf, rather than a separate inland sea.[13] About 20 to 16 million years ago, uplift formed the Coast Range and separated the basin from the Pacific Ocean.[12]

Basalts of the Columbia River Basalt Group, from eruptions in eastern Oregon, flowed across large parts of the northern half of the basin about 15 million years ago.[12] They covered the Tualatin Mountains (West Hills), most of the Tualatin Valley, and the slopes of hills further south, with up to 1,000 feet (300 m) of lava.[14] Later depositions covered the basalt with up to 1,000 feet (300 m) of silt in the Portland and Tualatin basins.[15] During the Pleistocene, beginning roughly 2.5 million years ago, volcanic activity in the Cascades combined with a cool, moist climate to produce further heavy sedimentation across the basin; braided rivers created alluvial fans spreading down from the east.[12]

The glacial Bellevue Erratic at Erratic Rock State Natural Site. The rock was transported to the Willamette Valley by the Missoula Floods.

Between about 15,500 and 13,000 years ago, the Missoula Floods, a series of large outpourings originating at Glacial Lake Missoula in Montana, swept down the Columbia River and backfilled the Willamette watershed.[12] Each flood produced "discharges that exceeded the annual discharge of all the present-day rivers of the world combined".[6] Filling the Willamette basin to depths of 400 feet (120 m) in the Portland region, each flood created a temporary lake, Lake Allison, that stretched from Lake Oswego to near Eugene.[16] The ancestral Tualatin Valley, part of the Willamette basin, flooded as well; water depths ranged from 200 feet (61 m) at Lake Oswego to 100 feet (30 m) as far upstream (west) as Forest Grove.[16] Flood deposits of silt and clay, ranging in thickness from 115 feet (35 m) in the north to about 15 feet (4.6 m) in the south, settled from this muddy water to form today's valley floor.[12] The floods carried Montana icebergs well into the basin, where they melted and dropped glacial erratics on the land's surface. These rocks, composed of granite and other materials common to central Montana but not to the Willamette Valley, include more than 40 boulders, each at least 3 feet (0.9 m) in diameter.[17] Before being partly chipped away and removed, the largest of these originally weighed about 160 short tons (150 t).[17]

The northern part of the watershed is underlain by a network of faults capable of producing earthquakes at any time, and many small quakes have been recorded in the basin since the mid-19th century.[18] In 1993, the largest recent earthquake in the valley, measuring 5.6 on the Richter scale, was centered near Scotts Mills, about 34 miles (55 km) south of Portland.[19] It caused $30 million in damage, including harm to the Oregon State Capitol in Salem.[20] Evidence suggests that massive quakes of 8 or more on the Richter scale have occurred historically in the Cascadia subduction zone off the Oregon coast, most recently in 1700 CE, and that others will occur.[21] The basin's high population density, its nearness to this subduction zone, and its loose soils, which tend to amplify shaking, make the Willamette Valley especially vulnerable to damage from strong earthquakes.[18]

Watershed

The river flowing by Mount Pisgah in Lane County

The Willamette River drains a region of 11,478 square miles (29,730 km2), which is 12 percent of the total area of Oregon.[22] Bounded by the Coast Range to the west and the Cascade Range to the east, the river basin is about 180 miles (290 km) long and 100 miles (160 km) wide.[6] Elevations within the watershed range from 10,495 feet (3,199 m) at Mount Jefferson in the Cascade Range[6] to 10 feet (3.0 m) at the confluence with the Columbia River.[3] Watersheds bordering the Willamette River basin are those of the Little Deschutes River to the southeast, the Deschutes River to the east, and the Sandy River to the northeast; the North Umpqua and Umpqua Rivers to the south; coastal rivers including (from south to north) the Siuslaw, the Alsea, the Yaquina, the Siletz, the Nestucca, the Trask, and the Wilson, to the west; the Nehalem and Clatskanie to the northwest, and the Columbia River to the north.[23]

About two million people lived in the Willamette River basin, 86 percent of them in urban areas, as of 2005.[24] This amounted to about 70 percent of the total population of Oregon.[25] As of 2009, the basin contained 20 of the 25 most populous cities in Oregon.[1][26] Cities with populations of 20,000 or more along the main stem include Springfield, Eugene, Corvallis, Albany, Salem, Keizer, Newberg, Oregon City, West Linn, Milwaukie, Lake Oswego, and Portland.[1][26] The largest is Portland, with more than 500,000 residents.[26] Other cities in the watershed (but not on the main-stem river) with populations of 20,000 or more as of 2009 are Gresham, Hillsboro, Beaverton, Tigard, McMinnville, Tualatin, Woodburn, and Forest Grove.[1][26]

Sixty-four percent of the watershed is privately owned, while 36 percent is publicly owned.[24] The United States Forest Service manages 30 percent of the watershed, the U.S. Bureau of Land Management 5 percent, and the State of Oregon 1 percent.[24] Sixty-eight percent of the watershed is forested; agriculture, concentrated in the Willamette Valley, makes up 19 percent, and urban areas cover 5 percent.[24] More than 81,000 miles (130,000 km) of roads criss-cross the watershed.[24]

In 1987, the United States Secretary of the Interior designated 713 acres (289 ha) of the watershed in Benton County as a National Natural Landmark. Called the Willamette Floodplain, it is the largest remaining unplowed native grassland in the region.[27]

History

First inhabitants

The Willamette River near the confluence with the Molalla River

For at least 10,000 years, a variety of indigenous peoples populated the Willamette Valley. These included the Kalapuya, the Chinook, and the Clackamas, among others.[28] The territory of the Clackamas encompassed the northeastern portion of the basin, including the Clackamas River (with which their name is shared). During at least some points in history, the territory of the Chinook also extended across the northern part of the watershed, through the Columbia River valley. Indigenous peoples of the Willamette Valley were further divided into groups including the Yamhill, Atfalati (Tualatin), Molala, Santiam, Chuchsney-Tufti, Muddy Creek, Long Tom, Yoncalla, Siuslaw, Calapooia, Chepenafa and Luckiamute, many of which were part of the larger Kalapuya group.[22][28] The name Willamette is also of indigenous origin, deriving from the French pronunciation of the name of a Clackamas Native American village.[29] However, Native American languages in Oregon were very similar,[30] so the name may also be derived from Kalapuya dialects.[31]

Around the year 1850, the Kalapuya numbered between 2,000 and 3,000 and were distributed among several groups. These figures are only speculative; there may have been as few as eight subgroups or as many as 16.[32] In that time period, the Clackamas' tribal population was roughly 1,800.[33] The Chinook population was estimated at nearly 5,000,[34] though not all of the Chinook lived on the Willamette. The Chinook territory encompassed the lower Columbia River valley and significant stretches of the Pacific coast on both the north and the south side of the Columbia's mouth. At times, however, the Chinook territory extended even farther up the Willamette Valley, well south of the Columbia River.[35] The total native population was estimated at about 15,000.[28]

The indigenous peoples of the Willamette River practiced a variety of life ways. Those on the lower river, closer to the coast, often relied on fishing as their primary economic mainstay. Salmon was the most important fish to Willamette River tribes as well as to the Native Americans of the Columbia River, where white traders traded fish with the Native Americans. Upper-river tribes also caught Steelhead and salmon, often by building weirs across tributary streams. Tribes of the northern Willamette Valley practiced a generally settled lifestyle. The Chinooks lived in great wooden lodges,[36] practiced slavery, and had a well-defined caste system.[36] People of the south were more nomadic, traveling from place to place with the seasons. They were also known for the controlled burning of woodlands to create meadows for hunting and plant gathering (especially camas).[37]

Fur trade

See also: Maritime Fur Trade

The Willamette River first entered the records of outsiders in 1792, when it was seen by British Lieutenant William Robert Broughton of the Vancouver Expedition, led by George Vancouver.[38] From the 18th to the mid-19th centuries, much of the Pacific Northwest and most of its rivers were involved in the fur trade, in which fur trappers (mostly French-Canadians working for the Hudson's Bay Company and the North West Company, which later merged) hunted for beaver and sea otter on rivers, streams, and coastlines. The pelts of these animals commanded substantial prices in either the United States, Canada or eastern Asia, because of their "thick, luxurious and water-repellent" qualities.[39]

The Willamette River and its tributaries were also heavily exploited; the Willamette area was even referred to as the "Willamette River fur trade".[40] During this period, the Siskiyou Trail (or California-Oregon Trail) was also created. This trading path, over 600 miles (970 km) long, stretched from the mouth of the Willamette River near present-day Portland south through the Willamette Valley, crossing the Cascades and the Siskiyou Mountains, and south through the Sacramento Valley to San Francisco, California.[41]

19th-century development

In 1805, the Lewis and Clark Expedition traveled thousands of miles across central North America in an attempt to map and explore the Louisiana Territory of the United States and the Oregon Country, which then was occupied mainly by Native Americans and settlers from Great Britain. As the expedition traveled down and back up the Columbia River, it entirely missed the mouth of the Willamette, even though the Willamette was one of the Columbia's largest tributaries. It was only after receiving directions from natives along the Sandy River that the explorers learned about the Willamette. William Clark returned down the Columbia and entered the Willamette River in April 1806.[6] The United States Exploring Expedition passed through the Willamette Valley in 1841 while traveling along the Siskiyou Trail of present-day Oregon and California. The members of the expedition noted that extensive salmon fishing was going on at Willamette Falls, much like at Celilo Falls on the Columbia River.[42]

In the middle part of the 19th century, the Willamette Valley's fertile soils, pleasant climate and abundant water attracted thousands of settlers from the eastern United States, mainly the Upland South borderlands of Missouri, Iowa, and the Ohio Valley.[43] Many of these emigrants followed the Oregon Trail, a 2,170-mile (3,490 km) trail across western North America that began at Independence, Missouri, and ended at various locations near the mouth of the Willamette River. Although people had been traveling to Oregon since 1836, large-scale migration did not begin until 1843, when nearly 1,000 pioneers headed westward. Over the next 25 years, some 500,000 settlers traveled the Oregon Trail, braving the rapids of the Snake and Columbia Rivers to reach the Willamette Valley.[44][45][46]

Oregon City circa 1867, with Willamette Falls in the background

Oregon City grew up around Willamette Falls beginning in the 1820s. Incorporated in 1844, it was the first city west of the Rocky Mountains to have that distinction.[47] John McLoughlin, a Hudson's Bay Company (HBC) official, was one of the major contributors to the founding of the town in 1829.[48] McLoughlin attempted to persuade the British government (which still held sway over the area) to allow American settlers to live on the land, and provided significant help to American colonization of the area, all against the HBC's orders.[49] Oregon City prospered because of the paper mills that were run by the water power of Willamette Falls, but the falls formed an impassable barrier to river navigation. Linn City (originally Robins Nest) was established across the Willamette from Oregon City.[50]

After Portland was incorporated in 1851, quickly growing into Oregon's largest city, Oregon City began to slowly lose its importance as the economic and political center of the Willamette Valley. Beginning in the 1850s, steamboats began to ply the Willamette, despite the fact that they could not pass Willamette Falls.[51] As a result, navigation on the Willamette River was divided into two stretches: the 27-mile (43 km) lower stretch from Portland to Oregon City—which allowed connection with the rest of the Columbia River system—and the upper reach, which encompassed most of the Willamette's length.[52] Any boats whose owners found it absolutely necessary to get past the falls had to be portaged. This created strong competition among steam companies and portage companies.[53][54] In 1873, the construction of the Willamette Falls Locks bypassed the falls and allowed easy navigation between the upper and lower river. Each lock chamber measured 210 feet (64 m) long and 40 feet (12 m) wide, and the canal was originally operated manually before it switched to electrical power.[54] Today, the lock system is little used.[55]

As commerce and industry flourished on the lower river, most of the original settlers acquired farms in the upper Willamette Valley. By the late 1850s, farmers had begun to grow crops on most of the available fertile land.[56] The settlers increasingly encroached on Native American lands. Skirmishes between natives and settlers in the Umpqua and Rogue valleys to the southwest of the Willamette River led the Oregon state government to remove the natives by military force.[57] They were first led off their traditional lands to the Willamette Valley, but soon were marched to the Siletz Reservation on the coast. Joel Palmer, a pioneer and legislator of the Oregon government, who had been involved with driving out the Umpqua and Rogue peoples, later forced tribes of the Willamette Valley to sign a treaty that transferred 7,500,000 acres (30,000 km2) of their land to the United States government for $200,000.[58][59] The natives of the Willamette Valley were similarly moved into the Siletz Reservation, which since has shrunk to a fraction of its former size.[60] Palmer, later criticized for bringing unnecessary risk to white settlers by angering the Native Americans and for often treating them unlawfully, was removed from the legislature in 1856.[61] However, by that year, further conflicts with Native Americans saw the last of the tribes being removed from the valley.[62]

Between 1879 and 1885, the Willamette River was charted by Cleveland S. Rockwell, a topographical engineer and cartographer for the U.S. Coast and Geodetic Survey. Rockwell surveyed the lower Willamette from the foot of Ross Island through Portland to the Columbia River and then downstream on the Columbia to Bachelor Island.[63] Rockwell's survey was extremely detailed, including 17,782 hydrographic soundings. His work helped open the port of Portland to commerce.[64]

20th and 21st centuries

Conveyor belt loading debris onto a barge as part of the Big Pipe Project

In the early 20th century, major river-control projects had begun to take place. Levees were constructed along the river in most urban areas, and Portland built concrete "seawalls" to protect its downtown sector.[8] In the following decades, many large dams were built on Cascade Range tributaries of the Willamette. In 2011, the Army Corps of Engineers operates 13 such dams, which affect flows from about 40 percent of the basin.[65]

With development in and near the river came increased pollution. By the late 1930s, efforts to stem the pollution led to formation of a state sanitary board to oversee modest cleanup efforts.[22] In the 1960s, Oregon Governor Tom McCall led a push for stronger pollution controls on the Willamette.[66] To enhance historical, natural, and recreational values along the river, the Oregon State Legislature established the Willamette Greenway program in 1967. Through it, state and local governments cooperated in creating or improving a system of parks, trails, and wildlife refuges along the river.[38] In 1998, the Willamette became one of 14 rivers designated an American Heritage River by former U.S. President Bill Clinton.[67] By 2007 the Greenway had grown to include more than 170 separate land parcels, including 10 state parks.[38] Public uses of the river and land along its shores include camping, swimming, fishing, boating, hiking, bicycling, and wildlife viewing.[38]

A 1991 agreement between the City of Portland and the State of Oregon to dramatically reduce combined sewer overflows (CSOs),[68] led to Portland's "Big Pipe Project". The long-term project has been separating the city's sanitary sewer lines from storm-water inputs that tend to overwhelm the combined system during heavy rains. When that happens, some of the raw sewage in the system goes into the river instead of the city's wastewater treatment plant. Big Pipe and related work is projected to reduce CSO volume on the lower river by more than 94 percent by the end of 2011.[69][70]

Dams and bridges

Dams

At 463 feet (141 m) high, Detroit Dam is the largest dam in the Willamette River basin.

There are more than 15 major dams on the Willamette's tributaries as well as a complex series of levees, dikes, and channels to control the river's flow. The only dam on the Willamette's main stem, however, is the Willamette Falls Dam, a low weir-type structure at Willamette Falls that diverts water into the headraces of the adjacent mills and a power plant.[71] The dams on the Willamette's major tributaries are primarily large flood-control, water storage, and power-generating dams. They are used to regulate river flows so as to cut peaks off floods and increase low flows in late summer and autumn.[65] Thirteen of these dams were built by the U.S. Army Corps of Engineers, and eleven of them produce hydropower. Most of the other ones are owned by state or local interests. USACE flood-control dams are estimated to hold over up to 27 percent of the river's runoff. On the main stem, numerous flow regulation structures force the river into a narrower and deeper channel to facilitate navigation and flood control.[38]

Large dams and their reservoirs include Hills Creek, Lookout Point, Dexter, and Fall Creek on the Middle Fork and its tributaries; Cottage Grove on the Coast Fork; Cougar on the South Fork McKenzie; Fern Ridge on the Long Tom River; Green Peter, Foster, Detroit, and Big Cliff on various forks of the Santiam; and North Fork, Faraday, Oak Grove, and Timothy on the Clackamas and its forks.[71][72] Detroit Dam on the North Santiam River, by far the largest, is 463 feet (141 m) high and stores 455,000 acre-feet (561,000,000 m3) of water.[73] USACE dam facilities in the basin are collectively known as the Willamette River Basin Project.[74]

Portions of the Willamette River have also been modified for navigation purposes. The U.S. federal government maintains a navigation channel for 11.6 miles (18.7 km) along the Willamette from the mouth, and the river is regularly dredged to maintain a depth of at least 40 feet (12 m) and a width of 600 feet (180 m) (although the river broadens to 2,000 feet (610 m) in some of its lower reaches). This channel forms the primary navigational conduit for Portland's harbor and riverside industrial areas.[75] Proposals have been made for deepening the channel to 43 feet (13 m) in conjunction with roughly 103.5 miles (166.6 km) of tandem-maintained navigation on the Columbia River.[76] Between the 1850s and the 1960s, channel-straightening and flood control projects, as well as agricultural and urban encroachment, cut the length of the river between the McKenzie River confluence and Harrisburg by 65 percent. Similarly, the river was shortened by 40 percent in the stretch between Harrisburg and Albany.[77]

Bridges

The Hawthorne Bridge is the oldest remaining highway structure over the Willamette.

The 50 or so crossings of the Willamette River include many historic structures, such as the Van Buren Street Bridge (a swing bridge). Built in 1913, it carries Oregon Route 34 (Corvallis–Lebanon Highway) over the river upstream of RM 131 (RK 211) in Corvallis. The machinery to operate the swing span was removed in the 1950s.[78][79] The Oregon City Bridge, built in 1922, replaced a suspension span constructed at the site in 1888. It carries Oregon Route 43 over the river at about RM 26 (RK 42) between Oregon City and West Linn.[80][81]

The Ross Island Bridge, which carries U.S. Route 26 (Mount Hood Highway) over the river at RM 14 (RK 23), is the furthest upriver of 10 highway bridges that cross the Willamette River in Portland's central business district. The 3,700-foot (1,100 m) bridge is the only cantilevered deck truss in Oregon.[82][83] Built in 1910, the Hawthorne Bridge, slightly downriver from the Ross Island Bridge, is the oldest remaining highway structure over the Willamette.[84]

The lower deck of the Steel Bridge can be raised independently of the upper deck.

Another historic structure, the Steel Bridge, further downstream, was "the largest telescoping bridge in the world at the time of its opening" in 1912.[85] It carries trains on its lower deck, MAX (Metropolitan Area Express) light-rail trains as well as motorized vehicles on its upper deck, and foot and bicycle traffic on a cantilevered walkway attached to the lower deck.[86] Its double vertical-lift span can raise a lower railway deck to allow small ships to pass through without disturbing traffic on the upper deck. When a large ship approaches, operators can raise both decks as high as 163 feet (50 m) above the water. The bridge is "believed to be the world's only double-lift span that can raise its lower deck independently of the upper deck."[85]

The Broadway Bridge, slightly downstream of the Steel Bridge, was the world's longest double-leaf bascule drawbridge at the time of its construction in 1913.[87] Further downriver, the St. Johns Bridge, a steel suspension bridge built in 1931, replaced the last of the Willamette River ferries in Portland.[88] The bridge, at about RM 6 (RK 10), carries U.S. Route 30 Bypass.[89]

Flooding

Due to the volume and seasonality of precipitation in its valley, the Willamette River is known for flooding. In 1861, rainstorms and warm temperatures combined with a well-above-average snowpack in the Cascades created the largest Willamette River flood in recorded history. An observer of the flood said, "The whole Willamette valley [sic] was a sheet of water".[90] From Eugene to Portland, thousands of acres of rich riverside farmland were washed away and many towns in the valley were damaged or destroyed. The Great Flood, as it is sometimes called, was massively destructive to human development because most of that development was located in the river's floodplain. Floodplain locations offer easy access to river transportation and the best soils for farming. The 1861 flood peaked at 635,000 cubic feet per second (18,000 m3/s)—which was more than the flow of the Mississippi River—and inundated some 353,000 acres (1,430 km2) of land.[8][90]

An aerial view of the 1996 flooding

In the summer of 1866, the Willamette was measured at 21 feet (6.4 m) above the "low water mark," and there were more flooding worries. This raised the level of the Columbia River and nearly flooded The Dalles, a city on the Columbia.[91]

The floods returned in early 1890, when the river first rose very quickly and then fell very quickly.[92][93] Portland's main street was completely submerged. Communication over the Cascades was cut off, and many rail lines were forced to shut down.[93] In 1894, another major flood occurred on the Willamette, and although it too caused huge damage, it was not quite as large as that of 1861.[8]

Diagram of the flooding near Salem in 1996

In the 1940s the Willamette caused more flooding in the valley. It destroyed five bridges in Lane County in December 1942,[94] caused seven deaths in Portland and forced people in Eugene to evacuate in January 1943,[95][96] caused minor flooding in Corvallis in November 1946,[97] and nearly flooded parts of Salem in December 1948.[98]

Although the Willamette was, by mid-century, heavily engineered and controlled by a complex system of dams, channels and barriers, it experienced severe floods through the end of the century. A major flood swelled the Willamette and other rivers in the Pacific Northwest from December 1964 through January 1965, submerging nearly 153,000 acres (620 km2) of land.[99]

Before dawn on December 21, 1964, the Willamette reached 29.4 feet (9.0 m), which was higher than the Portland seawall. By this time, about 15 people had died as a result of the flooding and about 8,000 Oregonians had been forced to evacuate their homes in search of other shelter.[100] On December 24, President Lyndon B. Johnson ordered federal aid for the flooded areas. Meanwhile, the Willamette continued to rise.[101] In the next couple of days, the river receded, but on December 27, it was at 29.8 feet (9.1 m), which was still nearly 12 feet (3.7 m) above flood stage.[102] The Willamette continued to pose flooding threats through January 1965,[103] and more stormy weather occurred along the Pacific Coast.[104]

The river crested at one town after another — at Corvallis 3½ feet above flood stage, Oregon City 18 feet above, Portland 10.5 feet above — much like a meal moving through a boa constrictor.

— Associated Press journalist, February 10, 1996, [105]

In February 1996, very heavy warm rains driven by a subtropical jet stream fell on a high, water-heavy snowpack in the Willamette watershed. These conditions, similar to those that caused the 1861 flood, caused some of the costliest flooding in the river's recorded history.[106] An Associated Press journalist said about the flood, "The river crested at one town after another — at Corvallis 3½ feet above flood stage, Oregon City 18 feet above, Portland 10.5 feet above — much like a meal moving through a boa constrictor."[105] The flood also interrupted the progress of Oregon's economy.[107] However, the inundated acreage was even smaller than 1964—only about 117,000 acres (470 km2).[99]

In April 1996, about 450 concrete flood-protection walls that had been built in Portland during the flood were removed. Each wall weighed roughly 5,500 pounds (2,500 kg).[108] In October, however, a new wall was built near Portland. The wall had 6.35-millimetre (0.250 in) removable steel plates to prevent further flooding. The wall cost about $300,000.[109]

Pollution

The Tom McCall Waterfront Park is named after an Oregon governor who led a cleanup of the river.

Since as early as 1869, with the introduction of a federally-funded "snag puller" designed to keep the waterway clear, human habitation has affected the ecology of the river basin. The construction of large federal dams on the Willamette's tributaries between 1941 and 1969 damaged the spawning grounds for spring Chinook salmon and steelhead trout. Domestic and industrial waste from the cities built up along the river, "essentially turning the main-stem river into an open sewer by the 1920s."[22]

A 1927 Portland City Club report labeled the waterway "filthy and ugly," and identified the City of Portland as the worst offender. The Oregon Anti-Stream Pollution League brought a pollution-abatement measure before the 1937 Oregon Legislature. The bill passed, but Governor Charles Martin vetoed it. The Izaak Walton League and the Oregon Wildlife Federation countered the governor's veto with a ballot initiative, which passed in November 1938.[22]

Shortly after he was elected in 1966, Governor Tom McCall ordered water quality tests on the Willamette, conducted his own research on the water quality, and became head of the Oregon Sanitary Authority. McCall learned that the river was heavily polluted in Portland. In a television documentary, "Pollution in Paradise", he said that "the Willamette River was actually cleaner when the Oregon Sanitary Authority was created in 1938 than it was in 1962."[66] He then discouraged tourism in the state and made it harder for companies to qualify for a permit to operate near the river. He also regulated how much those companies could pollute and closed plants that did not meet state pollution standards.[110][111]

State studies in the 1990s identified a wide variety of pollutants in the river bottom, including heavy metals, polychlorinated biphenyls (PCBs), and pesticides along the lower 12 miles (19 km) of the river.[112] As a result, this section of the river was designated a Superfund site in 2000,[113] involving the United States Environmental Protection Agency (EPA) in cleanup of the river bottom.[114] The initial cleanup is focused on the portion between Swan Island and Sauvie Island.[115] Further upstream, the pressing environmental issues have been mainly variations in pH and dissolved oxygen.[116] The river is clean enough to be used by communities such as Tigard for drinking water.[117] In Portland, pollution is exacerbated by combined sewer overflows, which the city is greatly reducing through its Big Pipe Project.[118]

Despite pollution concerns, the Willamette River in general scores relatively high on the Oregon Water Quality Index (OWQI), which is compiled by the Oregon Department of Environmental Quality (DEQ). The DEQ considers index scores of less than 60 to be very poor; the other categories are 60–79 (poor); 80–84 (fair); 85–89 (good), and 90–100 (excellent).[119] The Willamette River's water quality is rated excellent near the source, though it gradually declines to fair near the mouth. Between 1998 and 2007, the average score for the upper Willamette at Springfield (RM 185, RK 298) was 93. At Salem (RM 84, RK 135), the score was 89, and good scores continued all the way to the Hawthorne Bridge in Portland (RM 13, RK 21) at 85. Scores were in the "fair" category further downstream; the least favorable reading was at the Swan Island Channel midpoint (RM 0.5, RK 0.8) at 81. By comparison, sites on the Winchuck River, the Clackamas, and the North Santiam all scored 95, and a site at a pump station on Klamath Strait Drain between Upper Klamath Lake and Lower Klamath Lake recorded the lowest score in Oregon at 19.[120]

Flora and fauna

Osprey are among bird species often seen along the Willamette River.

Loss of floodplain forests is among the larger changes to the Willamette River over the past 150 years. In 1850, an estimated 89 percent of a 400-foot (120 m) band along each river bank was covered by forests.[121] By 1990 only 37 percent of this zone was forested; the rest had been converted to farm fields or urban or suburban uses.[121] The remaining forests close to the river include large stands of black cottonwood, Oregon ash, willow, and bigleaf maple.[121] The central valley, formerly a perennial grass prairie interspersed with oaks, ponderosa pines, and other trees, is devoted almost entirely to farming. Douglas-fir, western hemlock, and western red cedar dominate the forest on the Coast Range side of the basin. Forests to the east in the Cascade Range include Pacific silver fir as well as western hemlock and western red cedar.[4]

Fish in the Willamette basin include 31 native species, among them cutthroat, bull, and rainbow trout, several species of salmon, sucker, minnow, sculpin, and lamprey, as well as sturgeon, stickleback, and others. Among the 29 non-native species in the basin, there are brook, brown, and lake trout, largemouth and smallmouth bass, walleye, carp, bluegill, and others. In addition to fish, the basin supports 18 species of amphibians, such as the Pacific giant salamander. Beaver and river otter are among 69 mammal species living in the watershed, also frequented by 154 bird species, such as the American Dipper, Osprey, and Harlequin Duck. Garter snakes are among the 15 species of reptiles found in the basin.[122]

Species diversity is greatest along the lower river and its tributaries. Threatened, endangered, or sensitive species include spring Chinook salmon, winter steelhead, Oregon chub, chum salmon, and Coho salmon.[122] In the central valley, there have been several projects that have restored and protected wetlands[123] in order to provide and preserve habitat for Bald Eagles, Fender's blue butterfly (of which 6,000 remain), Oregonichthys (a species of chub), Lomatium bradshawii (Bradshaw's desert parsley), Erigeron decumbens var. decumbens (Willamette Daisy), and Lupinus sulphureus (Kincaid's lupine).[124][125] In the early 21st century, osprey populations are increasing along the river, possibly because of a ban on the pesticide DDT and on the birds' ability to use power poles for nesting.[126] Beaver populations, presumed to be much lower than historic levels, are increasing throughout the basin.[126]

The Willamette River as it passes through Portland, Oregon.

See also

Notes and references

Notes

References

  1. ^ a b c d e Oregon Atlas & Gazetteer (Map) (1991 ed.). DeLorme Mapping. § 41–43, 47–48, 53, 59–60, 66. ISBN 0-89933-235-8.
  2. ^ a b United States Geological Survey (USGS). "United States Geological Survey Topographic Map". TopoQuest. Retrieved June 29, 2010. Relevant map quadrangles include Eugene East, Coburg, Junction City, Harrisburg, Peoria, Riverside, Lewisburg, Albany, Monmouth, Salem West, Mission Bottom, Dayton, St. Paul, Newberg, Sherwood, Canby, Lake Oswego, Portland, Linnton, Sauvie Island, and Saint Helens.
  3. ^ a b "Willamette River". Geographic Names Information System. United States Geological Survey, United States Department of the Interior. November 28, 1980. Retrieved June 25, 2010. Source and mouth elevation derived from Google Earth search using GNIS source and mouth coordinates.
  4. ^ a b c d e f Benke, et al., p. 617
  5. ^ Kammerer, J.C. (May 1990). "Largest Rivers in the United States". United States Geological Survey. Retrieved July 2, 2010.
  6. ^ a b c d e f Benke, et al., p. 616
  7. ^ a b Cite error: The named reference Morrison Bridge gauge was invoked but never defined (see the help page).
  8. ^ a b c d "Willamette River Multi-Purpose Development in the 1930s" (PDF). Army Engineers and the Development of Oregon: A History of the Portland District U.S. Army Corps of Engineers. U.S. Army Corps of Engineers. 1983. p. 107. Retrieved June 6, 2010.
  9. ^ "Tidally-Influenced Waterways". Public Ownership of Submerged and Submersible Land. State of Oregon. Retrieved July 2, 2010.
  10. ^ Caldwell, James M. "Sediment Oxygen Demand in the Lower Willamette River, Oregon, 1994" (PDF). Oregon Department of Environmental Quality. p. 2. Retrieved July 2, 2010. {{cite web}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  11. ^ National Weather Service Forecast Office, Portland, Oregon (2008). "Local Tide Predictions and Water Levels". U.S. Department of Commerce. Retrieved July 2, 2010.{{cite web}}: CS1 maint: multiple names: authors list (link)
  12. ^ a b c d e f g Wallick, Jennifer Rose (2007). "Patterns and Controls on Historical Channel Change in the Willamette River, Oregon, USA" (PDF). United States Forest Service. pp. 495–97. Retrieved August 1, 2010. {{cite web}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  13. ^ Orr, p. 203
  14. ^ Orr, p. 206
  15. ^ Orr, p. 208
  16. ^ a b Orr, pp. 212–13
  17. ^ a b Orr, p. 214
  18. ^ a b Orr, pp. 215–19
  19. ^ Ludwin, R.S. (October 11, 1996). "Scotts Mills Earthquake Summary". University of Washington Department of Earth and Space Sciences. Retrieved July 31, 2010. {{cite web}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  20. ^ "Earthquake Education: Historic Earthquakes in the Pacific Northwest". Oregon Department of Geology and Mineral Industries. Retrieved July 31, 2010.
  21. ^ "Earthquake hazards in the Pacific Northwest". Oregon Department of Geology and Mineral Industries. Retrieved July 31, 2010.
  22. ^ a b c d e Cite error: The named reference Oregon Encyclopedia was invoked but never defined (see the help page).
  23. ^ Loy, et al., pp. 168–69
  24. ^ a b c d e Benke, et al., pp. 616–17
  25. ^ "Ground-water hydrology of the Willamette basin, Oregon". United States Geological Survey. Retrieved July 10, 2011.
  26. ^ a b c d "Oregon – Place 2009 Population Estimates". United States Census Bureau. Retrieved August 1, 2010.
  27. ^ "Willamette Floodplain". National Park Service. March 31, 2011. Retrieved April 11, 2011.
  28. ^ a b c Spores, Ronald (1993). "Too Small a Place: The Removal of the Willamette Valley Indians, 1850–1856". American Indian Quarterly. 17: 172. Retrieved June 7, 2010.
  29. ^ Bright, p. 567
  30. ^ Campbell, p. 120
  31. ^ "A bridge too far along to be renamed". The Register-Guard. Eugene, Oregon. March 18, 2010. p. B1. Retrieved July 29, 2011.
  32. ^ Thornton, p. 125
  33. ^ "Clackamas Indians". National Geographic. National Geographic Society. 1996. Retrieved June 6, 2010.
  34. ^ Snipp, p. 344
  35. ^ Ruby and Brown, p. 4
  36. ^ a b Ruby and Brown, p. 16
  37. ^ Deur and Turner, p. 220
  38. ^ a b c d e "Willamette River Recreation Guide" (PDF). Oregon State Marine Board. 2007. pp. 1–3, 10. Retrieved June 7, 2010.
  39. ^ "Fur trade". Columbia River History. Northwest Power and Conservation Council. 2010. Retrieved June 6, 2010.
  40. ^ Mackie, p. 115
  41. ^ Engeman, p. 63
  42. ^ Wilkes, pp. 341–374
  43. ^ Meinig, p. 71
  44. ^ "Introduction". The Oregon Trail. Idaho State University. Retrieved June 6, 2010.
  45. ^ "The Route West". The Oregon Trail. Idaho State University. Retrieved June 6, 2010.
  46. ^ "Where did the Oregon Trail Go? Reaching Oregon's Willamette Valley". People & Places. Oregon-California Trails Association. 2011. Retrieved June 6, 2010.
  47. ^ "Clackamas County". Oregon Blue Book. Oregon State Archives. 2011. Retrieved February 24, 2011.
  48. ^ Samson, p. 125
  49. ^ Holman, pp. 96–97
  50. ^ McArthur, p. 1022
  51. ^ Gulick, pp. 28–29
  52. ^ Gulick, p. 22
  53. ^ Timmen, pp. 14, 17, 27
  54. ^ a b Lewis, Alan (August 2006). "Conquering the Falls: The Willamette Falls Locks". History of the Willamette Falls. Willamette Falls Heritage Foundation. Retrieved June 6, 2010.
  55. ^ Balingit, Moriah (May 18, 2006). "Living on Borrowed Time". The Oregonian. Portland, Oregon: Willamette Falls Heritage Foundation. Retrieved June 6, 2010. {{cite news}}: Unknown parameter |coauthor= ignored (|author= suggested) (help)
  56. ^ "A Chronology of Farming in Oregon". Oregon Public Broadcasting. 2000. Retrieved June 6, 2010.
  57. ^ Edwards and Schwantes, p. 61
  58. ^ Edwards and Schwantes, p. 62
  59. ^ Jette, Melinda. "Kalapuya Treaty of 1855". The Oregon Encyclopedia. Portland State University. Retrieved June 6, 2010.
  60. ^ Edwards and Schwantes, p. 63
  61. ^ "Joel Palmer". The Oregon History Project. The Oregon Historical Society. 2002. Retrieved June 6, 2010.
  62. ^ "Indian Removal". Center for Columbia River History. Retrieved June 6, 2010.
  63. ^ U.S. Coast and Geodetic Survey, p. 76
  64. ^ Stenzel, pp. 37–39
  65. ^ a b "Sustainable Rivers: Willamette flow management" (PDF). Conservation that works in Oregon. The Nature Conservancy. Retrieved June 6, 2010.
  66. ^ a b Williams, p. 131
  67. ^ "American Heritage Rivers News". United States Environmental Protection Agency. November 19, 2009. Retrieved April 11, 2011.
  68. ^ Bacon, Sheila (November 2003). "West side Big Pipe". Northwest Construction. Retrieved June 3, 2008.
  69. ^ "East Side CSO Tunnel Project". City of Portland. Retrieved April 10, 2011.
  70. ^ "A big pipe". The Oregonian. Portland, Oregon: City of Portland. December 11, 2007. Retrieved June 3, 2008.
  71. ^ a b "Willamette Falls Hydroelectric Project, Oregon". Low Impact Hydropower Institute. Retrieved June 6, 2010.
  72. ^ USGS Topo Maps for United States (Map). Cartography by United States Geological Survey. ACME Mapper. Retrieved June 7, 2010.
  73. ^ Reinhardt, Bob. "Detroit Dam". The Oregon Encyclopedia. The Oregon Historical Society. Retrieved June 7, 2010.
  74. ^ "Willamette Basin". Federal Caucus. July 31, 2008. Retrieved June 6, 2010.
  75. ^ Bureau of Planning and Sustainability. "Willamette River Dredged Material Management Plan Project". City of Portland. Retrieved June 7, 2010.
  76. ^ "Background – Project". Columbia River Project—Columbia River Channel Improvement Reconsultation Project. Sustainable Ecosystems Institute. February 28, 2001. Retrieved June 7, 2010.
  77. ^ Laenen and Dunnette, p. 24
  78. ^ Smith, et al., p. 287
  79. ^ United States Geological Survey. "United States Geological Survey Topographic Map: Corvallis, Oregon, quadrangle". TopoQuest. Retrieved May 31, 2010.
  80. ^ Smith, et al., p. 96
  81. ^ United States Geological Survey. "United States Geological Survey Topographic Map: Oregon City, Oregon, quadrangle". TopoQuest. Retrieved June 1, 2010.
  82. ^ Smith, et al., p. 78
  83. ^ United States Geological Survey. "United States Geological Survey Topographic Map:Portland, Oregon, quadrangle". TopoQuest. Retrieved June 1, 2010.
  84. ^ Smith, et al., p. 115
  85. ^ a b Smith, et al., p. 208
  86. ^ Wortman, pp. 39–44
  87. ^ Smith, et al., p. 116
  88. ^ Smith, et al., p. 113
  89. ^ United States Geological Survey. "United States Geological Survey Topographic Map:Linnton, Oregon, quadrangle". TopoQuest. Retrieved June 5, 2010.
  90. ^ a b Allen, Cain (2004). "The Great Flood of 1861". Historical Records. Oregon Historical Society. Retrieved June 6, 2010.
  91. ^ "News of the day: general news" (PDF). The New York Times. New York, New York. July 1, 1866. Retrieved July 2, 2011.
  92. ^ "The floods and the storm". The Philadelphia Record. Philadelphia, Pennsylvania. February 9, 1890. p. 1. Retrieved July 2, 2011.
  93. ^ a b "Oregon's great floods" (PDF). The New York Times. New York, New York. February 7, 1890. Retrieved July 2, 2011.
  94. ^ "Floods wash out Oregon bridges". The Vancouver Sun. Vancouver, British Columbia. December 1, 1942. p. 1. Retrieved July 2, 2011.
  95. ^ Associated Press (January 2, 1943). "Lower river areas hit by flood crest". The Register-Guard. Eugene, Oregon. p. 1. Retrieved July 2, 2011.
  96. ^ United Press International (January 1, 1943). "Flood peril wanes in Ohio Valley". The Reading Eagle. Reading, Pennsylvania. pp. 1, 18. Retrieved July 2, 2011.
  97. ^ Associated Press (November 28, 1946). "Willamette River is nearing crest of flood stage". The Spokesman-Review. Spokane, Washington. p. 2. Retrieved July 2, 2011.
  98. ^ Associated Press (December 14, 1948). "River flood waters reach Oregon capital". The Telegraph-Herald. Dubuque, Iowa. p. 16. Retrieved July 2, 2011.
  99. ^ a b Gregory, S.; Jett, S.; Wildman, R. "Floods and Floodplains in the Willamette River" (PDF). Federal Emergency Management Agency. Corvallis Forestry Research Community. Retrieved June 6, 2010. {{cite web}}: More than one of |first1= and |first= specified (help); More than one of |last1= and |last= specified (help)
  100. ^ "Portland threatened by rampaging river". The Tri-City Herald. Kennewick, Washington. December 21, 1964. p. 20. Retrieved June 29, 2011.
  101. ^ "Floods spoil holiday in Oregon, California". The Spokesman-Review. December 25, 1964. p. 2. Retrieved June 29, 2011.
  102. ^ "Portland gets reprieve from a big flood threat". The Nevada Daily Mail. Nevada, Missouri. December 27, 1964. p. 1. Retrieved June 29, 2011.
  103. ^ United Press International (January 30, 1965). "1000 flee flood in Northwest; nation shivers". The Pittsburgh Press. Pittsburgh, Pennsylvania. p. 1. Retrieved July 2, 2011.
  104. ^ Associated Press (February 6, 1965). "Eastern deep freeze eases, but rain brings flood fears to West". The Lewiston Daily Sun. Lewiston, Maine. p. 1. Retrieved July 2, 2011.
  105. ^ a b Associated Press (February 10, 1996). "Swollen river spares downtown Portland". The Deseret News. Salt Lake City, Utah. p. A4. Retrieved June 25, 2011.
  106. ^ Taylor, George H. (November 1996). "The Great Flood of 1996: its causes and a comparison to other climate events" (PDF). Oregon State University. p. 2. Retrieved August 3, 2011.
  107. ^ Barnard, Jeff (February 25, 1996). "Flood spreads in economy like muddy water". The Rocky Mountain News. Denver, Colorado. Retrieved June 26, 2011.
  108. ^ "Flood wall comes down today in Portland". The Register-Guard. Eugene, Oregon. April 1, 1996. p. 3C. Retrieved June 26, 2011.
  109. ^ Associated Press (October 14, 1996). "Flood wall readied for next time". The Register-Guard. Eugene, Oregon. p. 5C. Retrieved June 27, 2011.
  110. ^ Williams, p. 132
  111. ^ The Los Angeles Times; The Washington Post (April 17, 1973). "Oregon sets pace in improving environment". The Sarasota Herald-Tribune. Sarasota, Florida. p. 20A. Retrieved July 17, 2011.
  112. ^ "Portland Harbor Cleanup Sites" (PDF). Oregon Department of Environmental Quality. February 17, 2009. Retrieved April 11, 2011.
  113. ^ Lee van der Voo (July 3, 2007). "History of a Superfund cleanup bid". Portland Tribune. Retrieved February 12, 2008.
  114. ^ "Portland Harbor Superfund Site". Oregon Department of Environmental Quality. Archived from the original on December 16, 2006. Retrieved December 16, 2006.
  115. ^ "Region 10 Cleanup: Portland Harbor". United States Environmental Protection Agency. Retrieved February 12, 2008.
  116. ^ "Processes Controlling Dissolved Oxygen and pH in the Upper Willamette River Basin" (PDF). U.S. Geological Survey. 1994. Retrieved February 12, 2008.
  117. ^ "Drinking the Willamette – the power of public education" (PDF). PNWS-AWWA 2008 Annual Conference. May 1, 2008. p. 4. Retrieved July 11, 2011.
  118. ^ "The Willamette River: a renaissance in the making" (PDF). Americanrivers.org. p. 140. Retrieved July 11, 2011.
  119. ^ Oregon Water Quality Index, p. 6
  120. ^ Oregon Water Quality Index, pp. 7–10
  121. ^ a b c Benke, et al., p. 619
  122. ^ a b Benke, et al., pp. 620–21
  123. ^ "Willamette Valley projects". Oregon Habitat Joint Venture. November 14, 2001. Retrieved July 11, 2011.
  124. ^ "Willamette Valley National Wildlife Refuge Complex". United States Fish and Wildlife Service. July 18, 2010. Retrieved July 11, 2011.
  125. ^ Zaveri, Mihir (June 17, 2011). "In Oregon's Willamette Valley, the race to save the endangered Fender's blue butterfly". The Oregonian. Portland, Oregon.
  126. ^ a b Benke, et al., p. 621

Works cited

  • — "Oregon Water Quality Index Summary Report, Water Years 1998–2007", May 2008. Oregon Department of Environmental Quality. Retrieved April 10, 2011.
  • Benke, Arthur C., ed., and Cushing, Colbert E., ed.; Stanford, Jack A.; Gregory, Stanley V.; Hauer, Richard F.; Snyder, Eric B. (2005). "Chapter 13: Columbia River Basin" in Rivers of North America. Burlington, Massachusetts: Elsevier Academic Press. ISBN 0-12-088253-1. OCLC 59003378.
  • Bright, William (2004). Native American Placenames of the United States. Norman, Oklahoma: University of Oklahoma Press. ISBN 0-8061-3576-X. OCLC 53019644.
  • Campbell, Lyle (1997). American Indian Languages. New York, New York: Oxford University Press. ISBN 0-19-509427-1. OCLC 247389024.
  • Deur, Douglas; Turner, Nancy J. (2005). Keeping it Living: Traditions of Plant Use and Cultivation on the Northwest Coast of North America. Seattle: University of Washington Press. ISBN 0-77481-267-2. OCLC 57316620.
  • Edwards, G. Thomas; Schwantes, Carlos A. (1986). Experiences in a Promised Land: Essays in Pacific Northwest History. Seattle: University of Washington Press. ISBN 0-29596-328-X. OCLC 12805717.
  • Engeman, Richard H. (2009). The Oregon Companion: A Historical Gazetteer of the Useful, the Curious, and the Arcane. Portland, Oregon: Timber Press. ISBN 0-88192-899-2. OCLC 236142647.
  • Gulick, Bill (2004). Steamboats on Northwest Rivers. Caldwell, Idaho: Caxton Press. ISBN 0-87004-438-9. OCLC 53000219.
  • Holman, Frederick Van Voorhies (1907). Dr. John McLoughlin, the Father of Oregon. Cleveland, Ohio: A. H. Clark Company. ISBN 1-13113-770-1. OCLC 365933029.
  • Laenen, Antonius; Dunnette, David A. (1997). River Quality: Dynamics and Restoration. Boca Raton, Florida: CRC Press. ISBN 1-56670-138-4. OCLC 34885999.
  • Loy, Willam G.; Allan, Stuart Allan; Buckley, Aileen R.; Meecham, James E. (2001) [1976]. Atlas of Oregon (2nd ed.). Eugene, Oregon: University of Oregon Press. ISBN 0-87114-101-9. OCLC 228223337.
  • Mackie, Richard Somerset (1997). Trading Beyond the Mountains: the British Fur Trade on the Pacific, 1793–1843. Vancouver: UBC Press. ISBN 0-77480-613-3. OCLC 82135549.
  • McArthur, Lewis A.; McArthur, Lewis L. (2003) [1928]. Oregon Geographic Names (7th ed.). Portland, Oregon: Oregon Historical Society Press. ISBN 0-87595-277-1. OCLC 53075956.
  • Meinig, D.W. (1998). The Shaping of America: A Geographical Perspective on 500 Years of History, Volume 3: Transcontinental America, 1850–1915. New Haven, Connecticut: Yale University Press. ISBN 0-300-08290-8. OCLC 60197763.
  • Orr, Elizabeth L.; Orr, William N. (1999). Geology of Oregon (5th ed.). Dubuque, Iowa: Kendall/Hunt Publishing Company. ISBN 0-7872-6608-6. OCLC 42944922.
  • Ruby, Robert H.; Brown, John A. (1976). The Chinook Indians: Traders of the Lower Columbia River. Civilization of the American Indian. Norman, Oklahoma: University of Oklahoma Press. ISBN 0-80612-107-6. OCLC 1958350.
  • Samson, Karl (2010). Frommer's Oregon. Hoboken, New Jersey: Wiley-Blackwell. ISBN 0-47053-771-X. OCLC 671277501.
  • Smith, Dwight A.; Norman, James B.; Dykman, Pieter T. (1989) [1986]. Historic Highway Bridges of Oregon (2nd ed.). Portland, Oregon: Oregon Historical Society Press. ISBN 0-87595-205-4. OCLC 20362124.
  • Snipp, C. Matthew (1989). American Indians: The First of This Land. New York, New York: Russell Sage Foundation. ISBN 0-87154-822-4. OCLC 19670797.
  • Stenzel, Franz (1972). Cleveland Rockwell: Scientist and Artist, 1837-1907. Portland, Oregon: Oregon Historical Society. ISBN 0-87595-037-X. OCLC 333762.
  • Thornton, Russell (1990). American Indian Holocaust and Survival: A Population History Since 1492. Civilization of the American Indian. Norman, Oklahoma: University of Oklahoma Press. ISBN 0-80612-220-X. OCLC 263150623.
  • Timmen, Fritz (1973). Blow for the Landing. Atglen, Pennsylvania: Schiffer. OCLC 38286714.
  • U.S. Coast and Geodetic Survey (1887). Report of the Superintendent of the U.S. Coast and Geodetic Survey Showing the Progress of the Work during the Fiscal Year Ending with June 1886. Washington, D.C.: Government Printing Office. OCLC 28937852.
  • Wilkes, Charles (1845). Narrative of the United States' Exploring Expedition, During the Years 1838, 1839, 1840, 1841, 1842: Condensed and abridged. London: Whittaker and Co. OCLC 602918838. {{cite book}}: External link in |title= (help)
  • Williams, Travis (2009). The Willamette River Field Guide. Portland, Oregon: Timber Press. ISBN 0-88192-866-6. OCLC 243601804.
  • Wortman, Sharon Wood; Wortman, Ed.; Norman, James B. (2006). The Portland Bridge Book (3rd ed.). Portland, Oregon: Urban Adventure Press. ISBN 0-9787365-1-6. OCLC 76928209.
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