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The Willamette River ( ) is a major
tributary A tributary, or affluent, is a stream A stream is a body of water (Lysefjord) in Norway Norway, officially the Kingdom of Norway,Names in the official and recognised languages: Bokmål Bokmål (, ; literally "book tongue") ...
of the
Columbia River The Columbia River (Upper Chinook Upper Chinook, endonym Kiksht, also known as Columbia Chinook, and Wasco-Wishram after its last surviving dialect, is a recently extinct language of the US Pacific Northwest. It had 69 speakers in 1990, of w ...

Columbia River
, accounting for 12 to 15 percent of the Columbia's flow. The Willamette's
main stem In hydrology Hydrology (from Ancient Greek, Greek wikt:ὕδωρ, ὕδωρ, ''hýdōr'' meaning "water" and wikt:λόγος, λόγος, ''lógos'' meaning "study") is the scientific study of the movement, distribution, and management of wat ...
is long, lying entirely in northwestern
Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

Oregon
in the United States. Flowing northward between the
Oregon Coast Range The Oregon Coast Range, often called simply the Coast Range and sometimes the Pacific Coast Range, is a mountain range A mountain range is a series of mountains ranged in a line and connected by high ground. A mountain system or mountain belt ...
and the
Cascade Range The Cascade Range or Cascades is a major mountain range A mountain range is a series of mountains ranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form, structur ...
, the river and its tributaries form the
Willamette Valley The Willamette Valley ( ) is a long valley in Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state) ...
, a basin that contains two-thirds of Oregon's population, including the state capital, Salem, and the state's largest city,
Portland Portland most commonly refers to: * Portland, Oregon, the largest city in the state of Oregon, in the Pacific Northwest region of the United States * Portland, Maine, the largest city in the state of Maine, in the New England region of the northeas ...

Portland
, which surrounds the Willamette's mouth at the Columbia. Originally created by
plate tectonics Plate tectonics (from the la, label=Late Latin Late Latin ( la, Latinitas serior) is the scholarly name for the written Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. L ...
about 35 million years ago and subsequently altered by
volcanism Volcanism (or volcanicity) is the phenomenon of eruption of molten rock (magma Magma () is the molten or semi-molten natural material from which all igneous rock Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magma ...
and erosion, the river's
drainage basin A drainage basin is any area of land where precipitation collects and drains off into a common outlet, such as into a river, bay, or other body of water. The drainage basin includes all the surface water from surface runoff, rain runoff, snowm ...

drainage basin
was significantly modified by the
Missoula Floods The Missoula floods (also known as the Spokane floods or the Bretz floods or Bretz's floods) were cataclysmic glacial lake outburst flood , Alaska, squeezes towards Gibert Point on 20 May 2002. The glacier is close to sealing off Russell Fjord ...
at the end of the most recent ice age. Humans began living in the watershed over 10,000 years ago. There were once many tribal villages along the lower river and in the area around its mouth on the Columbia. Indigenous peoples lived 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 in North America, and was thus the destination of many 19th-century pioneers traveling west along the
Oregon Trail The Oregon Trail was a east–west, large-wheeled wagon route and emigrant trail in the United States that connected the Missouri River to valleys in Oregon. The eastern part of the Oregon Trail spanned part of what is now the state of Kansas ...
. The river was an important transportation route in the 19th century, although
Willamette Falls The Willamette Falls is a natural waterfall on the Willamette River between Oregon City, Oregon, Oregon City and West Linn, Oregon, in the United States. It is the largest waterfall in the Northwestern United States by volume, and the seventeen ...

Willamette Falls
, just upstream from Portland, was a major barrier to boat traffic. In the 21st century, major highways follow the river, and roads cross the main stem on approximately 30 different bridges. In addition to sharing some of those, more than half a dozen bridges not open to motorized vehicles provide separate crossings for bicycles and pedestrians (mostly in the Eugene area), and several others are exclusively for rail traffic. There are also ferries that convey cars, trucks, motorcycles, bicycles, and pedestrians across the river for a fare and provided river conditions permit. They are the Buena Vista Ferry between Marion County and Polk County south of Independence and Salem, the
Wheatland Ferry
Wheatland Ferry
between Marion County and Polk County north of Salem and Keizer, and
Canby Ferry The Canby Ferry is a cable ferry in the U.S. state of Oregon that connects Canby, Oregon, Canby, and Wilsonville, Oregon, Wilsonville/Stafford, Oregon, Stafford in Clackamas County, Oregon, Clackamas County across the Willamette River. The service ...
in Clackamas County north of Canby. Since 1900, more than 15 large dams and many smaller ones have been built in the Willamette's drainage basin, 13 of which are operated by the
U.S. Army Corps of Engineers , colors = , battles = , battles_label = Wars , website = , commander1 = LTG Scott A. Spellmon , commander1_label = Comma ...
(USACE). The dams are used primarily to produce
hydroelectricity Hydroelectricity, or hydroelectric power, is electricity produced from hydropower Hydropower (from el, ὕδωρ, "water"), also known as water power, is the use of falling or fast-running water Water (chemical formula H2O) is ...
, to maintain reservoirs for recreation, and to prevent flooding. The river and its tributaries support 60 fish species, including many species of
salmon Salmon is the common name for several species of ray-finned fish Actinopterygii ( New Latin ('having rays') + Greek ( 'wing, fins')), members of which are known as ray-finned fishes, is a clade A clade (; from grc, , ''klados'', ...

salmon
and
trout Trout are species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms ...

trout
; this is despite the dams, other alterations, and pollution (especially on the river's lower reaches). Part of the
Willamette Floodplain
Willamette Floodplain
was established as a
National Natural Landmark The National Natural Landmarks (NNL) Program recognizes and encourages the conservation of outstanding examples of the natural history of the United States. It is the only national natural areas program that identifies and recognizes the best exa ...
in 1987 and the river was named as one of 14
American Heritage Rivers 245px, right American Heritage Rivers were designated by the United States Environmental Protection Agency The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with enviro ...
in 1998.


Course

The upper tributaries of the Willamette originate in the mountains south and southeast of
Eugene, Oregon Eugene ( ) is a city in the U.S. state of Oregon, in the Pacific Northwest. It is at the southern end of the Willamette Valley, near the confluence of the McKenzie River (Oregon), McKenzie and Willamette River, Willamette rivers, about east of t ...

Eugene, Oregon
. Formed by the confluence of the
Middle Fork Willamette River The Middle Fork Willamette River is one of several forks that unite to form the Willamette River in the western part of the U.S. state of Oregon. It is approximately long, draining an area of the Cascade Range southeast of Eugene, Oregon, Eugene, ...
and the
Coast Fork Willamette River The Coast Fork Willamette River is one of two forks that unite to form the Willamette River in western Oregon in the United States. It is about long, draining an area of the mountains at the south end of the Willamette Valley south of Eugene, Orego ...
near
Springfield Springfield may refer to: * Springfield (toponym) Springfield is a famously common place-name in the English-speaking world, especially in the United States. According to the USGS, U.S. Geological Survey there are currently 34 populated places na ...
, the
main stem In hydrology Hydrology (from Ancient Greek, Greek wikt:ὕδωρ, ὕδωρ, ''hýdōr'' meaning "water" and wikt:λόγος, λόγος, ''lógos'' meaning "study") is the scientific study of the movement, distribution, and management of wat ...
Willamette meanders generally north for to the
Columbia River The Columbia River (Upper Chinook Upper Chinook, endonym Kiksht, also known as Columbia Chinook, and Wasco-Wishram after its last surviving dialect, is a recently extinct language of the US Pacific Northwest. It had 69 speakers in 1990, of w ...

Columbia River
. The river's two most significant course deviations occur at Newberg, where it turns sharply east, and about downstream from Newberg, where it turns north again. Near its mouth north of downtown
Portland Portland most commonly refers to: * Portland, Oregon, the largest city in the state of Oregon, in the Pacific Northwest region of the United States * Portland, Maine, the largest city in the state of Maine, in the New England region of the northeas ...

Portland
, the river splits into two channels that flow around
Sauvie Island Sauvie Island, in the U.S. state In the , a state is a , of which there are currently 50. Bound together in a , each state holds al jurisdiction over a separate and defined geographic territory where it shares its with the . Due to thi ...
. Used for navigation purposes, these channels are managed by the U.S. federal government. The main channel, which is deep and varies in width from (although the river broadens to in some of its lower reaches), enters the Columbia about 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 A distributary, or a distributary channel, is a stream A stream is a body of water (Lysefjord) in Norway Norway, officially the Kingdom of Norway,Names in the official and recognised languages: Bokmål Bokmål (, ; literall ...
, is long, about wide, and deep. It ends about further downstream on the Columbia, near St. Helens in Columbia County. 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. Proposals have been made for deepening the Multnomah Channel to in conjunction with roughly of tandem-maintained navigation on the Columbia River. 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.
Interstate 5 Interstate 5 (I-5) is the main north–south Interstate Highway System, Interstate Highway on the West Coast of the United States, running largely parallel to the Pacific coast of the contiguous U.S. from Mexico to Canada. It travels t ...
and three branches of
Oregon Route 99 Oregon Route 99 is a state highway A state highway, state road, or state route (and the equivalent provincial highway, provincial road, or provincial route) is usually a road that is either ''numbered'' or ''maintained'' by a sub-national s ...

Oregon Route 99
are the two major highways that follow the river for its entire length. Communities along the main stem include Springfield and Eugene in Lane County;
Harrisburg Harrisburg ( ; Pennsylvania German language, Pennsylvania German: ''Harrisbarrig'') is the capital city of the Pennsylvania, Commonwealth of Pennsylvania in the United States, and the county seat of Dauphin County, Pennsylvania, Dauphin Count ...

Harrisburg
in Linn County; Corvallis in
Benton CountyBenton County is the name of nine counties in the United States: * Benton County, Arkansas * Benton County, Indiana * Benton County, Iowa * Benton County, Minnesota * Benton County, Mississippi * Benton County, Missouri * Benton County, Oregon ...
;
Albany Albany, derived from the Gaelic name for Scotland Scotland ( sco, Scotland, gd, Alba Alba (Scottish Gaelic Scottish Gaelic ( gd, Gàidhlig or Scots Gaelic, sometimes referred to simply as Gaelic) is a Goidelic language (in the C ...
in Linn and Benton counties; Salem in Marion County; Newberg in Yamhill County;
Oregon City ) , image_skyline = John McLoughlin House, Oregon City.JPG (3534603314).jpg , imagesize = , image_caption = The McLoughlin House, est. 1845 , image_flag = , image_seal = Oregon Ci ...

Oregon City
, West Linn, Milwaukie, and Lake Oswego in
Clackamas County Clackamas County is one of the Oregon counties, 36 counties in the U.S. state of Oregon. As of the 2010 United States Census, the population was 375,992, making it Oregon's third-most populous county. Its county seat is Oregon City, Oregon, Oregon ...
; and Portland in Multnomah and
Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** Federal government of the United States (metonym) ** Washington metropolitan area, the metropolitan area centered on Washingt ...
counties. Significant tributaries from source to mouth include the Middle and Coast forks and the McKenzie, Long Tom, Marys, , Santiam, Luckiamute, Yamhill, Molalla, , and Clackamas rivers. Beginning at above sea level, the main stem descends between source and mouth, or about 2.3 feet per mile (0.4 m per km). Source and mouth elevation derived from
Google Earth Google Earth is a computer program, formerly known as Keyhole EarthViewer, that renders a 3D computer graphics, 3D representation of Earth based primarily on satellite imagery. The program maps the Earth by superimposition, superimposing satell ...
search using GNIS source and mouth coordinates.
The gradient is slightly steeper from the source to Albany than it is from Albany to Oregon City.Benke, ''et al.'', p. 617 At
Willamette Falls The Willamette Falls is a natural waterfall on the Willamette River between Oregon City, Oregon, Oregon City and West Linn, Oregon, in the United States. It is the largest waterfall in the Northwestern United States by volume, and the seventeen ...

Willamette Falls
, between West Linn and Oregon City, the river plunges about . For the rest of its course, the river is extremely low-gradient and is affected by Pacific Ocean tidal effects from the Columbia. The main stem of the Willamette varies in width from about .


Discharge

With an average flow at the mouth of about , the Willamette ranks 19th in volume among rivers in the United States and contributes 12 to 15 percent of the total flow of the Columbia River. The Willamette's flow varies considerably season to season, averaging about in August to more than in December. The
U.S. Geological Survey The United States Geological Survey (USGS, formerly simply Geological Survey) is a scientific agency Agency may refer to: * a governmental or other institution Institutions, according to Samuel P. Huntington, are "stable, valued, recurrin ...
(USGS) operates five
stream gauge A stream gauge, streamgage or stream gauging station is a location used by hydrologists Hydrology (from Greek: ὕδωρ, "hýdōr" meaning "water" and wikt:λόγος, λόγος, "lógos" meaning "study") is the scientific study of the move ...
s along the river, at Harrisburg, Corvallis, Albany, Salem, and Portland. The average discharge at the lowermost gauge, near the Morrison Bridge in Portland, was between 1972 and 2013. Located at
river mile A river mile is a measure of distance in miles The mile, sometimes the international mile or statute mile to distinguish it from other miles, is a British imperial unit and US customary unit United States customary units (U.S. customary ...
(RM) 12.8 or river kilometer (RK) 20.6, the gauge measures the flow from an area of , roughly 97 percent of the Willamette basin. The highest flow recorded at this station was on February 9, 1996, during the Willamette Valley Flood of 1996, and the minimum was on July 10, 1978. The highest recorded flow of for the Willamette at a different gauge in Portland occurred during a flood in 1861. This and many other large flows preceded the
Flood Control Act of 1936 The Flood Control Act of 1936, , (FCA 1936) was an Act of the United States Congress signed into law by President Franklin Delano Roosevelt Franklin Delano Roosevelt (, ; January 30, 1882April 12, 1945), often referred to by his initial ...
and dam construction on the Willamette's major tributaries. The river below Willamette Falls, from the mouth, is affected by , and gauges have detected reverse flows (backwards river flows) below
Ross Island Ross Island is an island An island (or isle) is an isolated piece of habitat that is surrounded by a dramatically different habitat, such as water. Very small islands such as emergent land features on atoll An atoll (), sometim ...
at RM 15 (RK 24). The
National Weather Service The National Weather Service (NWS) is an agency Agency may refer to: * a governmental or other institution Institutions, according to Samuel P. Huntington, are "stable, valued, recurring patterns of behavior". Institutions can refer to m ...
issues tide forecasts for the river at the
Morrison Bridge The Morrison Bridge is a bascule bridge that spans the Willamette River in Portland, Oregon. Completed in 1958, it is the third bridge at approximately the same site to carry that name. It is one of the most heavily used bridges in Portland. It ...

Morrison Bridge
.


Geology

The Willamette River basin was created primarily by
plate tectonics Plate tectonics (from the la, label=Late Latin Late Latin ( la, Latinitas serior) is the scholarly name for the written Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. L ...
and
volcanism Volcanism (or volcanicity) is the phenomenon of eruption of molten rock (magma Magma () is the molten or semi-molten natural material from which all igneous rock Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magma ...
and was altered by erosion and sedimentation, including some related to enormous glacial floods as recent as 13,000 years ago.Wallick, ''et al.'', pp. 495–97 The initial trough-like configuration was created about 35 million years agoBenke, ''et al.'', p. 616 as a
forearc A forearc is the region between an oceanic trench , while the lithosphere is subducted back into the asthenosphere at trenches Oceanic trenches are prominent long, narrow topography, topographic depressions of the ocean floor. They are typically ...

forearc
basin while the
Pacific Plate The Pacific Plate is an oceanic tectonic plate This is a list of tectonic plates on Earth's surface Earth is the third planet A planet is an astronomical body orbiting a star or Stellar evolution#Stellar remnants, stellar remnant ...
subducted Subduction is a geological process in which the oceanic lithosphere A lithosphere ( grc, wikt:λίθος#Ancient Greek, λίθος [] for "rocky", and [] for "sphere") is the rigid, outermost shell of a terrestrial planet, terrestrial-type ...

subducted
beneath the
North American Plate The North American Plate is a tectonic plate This is a list of tectonic plates on Earth's surface Earth is the third planet A planet is an astronomical body orbiting a star or Stellar evolution#Stellar remnants, stellar remnant th ...
. Marine deposits on top of older volcanics underlie the valley, which was initially part of the
continental shelf A continental shelf is a portion of a continent A continent is any of several large landmass A landmass, or land mass, is a large region In geography Geography (from Greek: , ''geographia'', literally "earth descriptio ...

continental shelf
, rather than a separate inland sea. About 20 to 16 million years ago, uplift formed the Coast Range and separated the basin from the Pacific Ocean.
Basalt Basalt (, ) is a fine-grained extrusive A volcanic rock from Italy with a relatively large six-sided phenocryst (diameter about 1 mm) surrounded by a fine-grained groundmass, as seen in thin section under a petrographic microscope Extr ...

Basalt
s of the
Columbia River Basalt Group The Columbia River Basalt Group is the youngest, smallest and one of the best-preserved continental flood basalt province on Earth, covering over mainly eastern Oregon and Washington, western Idaho Idaho () is a U.S. state, state in the ...
, from eruptions in
eastern Oregon Eastern Oregon is the eastern part of the U.S. state of Oregon. It is not an officially recognized geographic entity; thus, the boundaries of the region vary according to context. It is sometimes understood to include only the eight easternmost ...

eastern Oregon
, flowed across large parts of the northern half of the basin about 15 million years ago. They covered the
Tualatin Mountains The Tualatin Mountains (also known as the West Hills or Southwest Hills of Portland) are a range on the western border of Multnomah County Multnomah County is one of the Oregon counties, 36 counties in the U.S. state of Oregon. As of the 2010 ...

Tualatin Mountains
(West Hills), most of the
Tualatin Valley The Tualatin Valley is a farming and suburban region southwest of Portland, Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern bou ...
, and the slopes of hills further south, with up to of
lava Lava is magma Magma () is the molten or semi-molten natural material from which all s are formed. Magma is found beneath the surface of the , and evidence of has also been discovered on other and some s. Besides molten rock, magma may al ...

lava
. Later depositions covered the basalt with up to of silt in the Portland and Tualatin basins. During the
Pleistocene The Pleistocene ( , often referred to as the ''Ice Age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the earth’s most recent period of repeated glaciations. Before a change finally ...
, 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 river A braided river, or braided channel, consists of a network of river channel Channel, channels, channeling, etc., may refer to: Geography * Channel (geography), in physical geography, a landform consisting of the outline (banks) of the path of ...
s created
alluvial fan An alluvial fan is an accumulation of sediments shaped like a section of a shallow cone, with its apex at a point source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to ...

alluvial fan
s spreading down from the east. Between about 15,500 and 13,000 years ago, the
Missoula Floods The Missoula floods (also known as the Spokane floods or the Bretz floods or Bretz's floods) were cataclysmic glacial lake outburst flood , Alaska, squeezes towards Gibert Point on 20 May 2002. The glacier is close to sealing off Russell Fjord ...
—a series of large outpourings originating at
Glacial Lake Missoula Lake Missoula was a prehistoric proglacial lake In geology, a proglacial lake is a lake formed either by the damming action of a moraine A moraine is any accumulation of unconsolidated debris (regolith and rock), sometimes referred to ...
in Montana—swept down the Columbia River and backfilled the Willamette watershed. Each flood produced "discharges that exceeded the annual discharge of all the present-day rivers of the world combined". Filling the Willamette basin to depths of in the Portland region, each flood created a temporary lake,
Lake Allison Lake Allison was a temporary lake in the Willamette Valley The Willamette Valley () is a long valley in Oregon Oregon () is a state in the Pacific Northwest region of the Western United States The Western United States (also called ...
, that stretched from Lake Oswego to near Eugene.Orr, pp. 212–13 The ancestral Tualatin Valley, part of the Willamette basin, flooded as well; water depths ranged from at Lake Oswego to as far upstream (west) as Forest Grove. Flood deposits of silt and clay, ranging in thickness from in the north to about in the south, settled from this muddy water to form today's valley floor. The floods carried Montana icebergs well into the basin, where they melted and dropped
glacial erratic A glacial erratic is glacially deposited rock Rock most often refers to: * Rock (geology) A rock is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its Chemical ...

glacial erratic
s on the land's surface. These rocks, composed of granite and other materials common to central Montana but not to the
Willamette Valley The Willamette Valley ( ) is a long valley in Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state) ...
, include more than 40 boulders, each at least in diameter.Orr, p. 214 Before being partly chipped away and removed, the largest of these originally weighed about . 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.Orr, pp. 215–19 In 1993, the Scotts Mills earthquake—the largest recent earthquake in the valley, measuring 5.6 on the
Richter scale The Richter scale – also called the Richter magnitude scale and Richter's magnitude scale – is a measure of the strength of earthquake An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Ear ...
—was centered near Scotts Mills, about south of Portland. It caused $30 million in damage, including harm to the
Oregon State Capitol The Oregon State Capitol is the building housing the Oregon Legislative Assembly, state legislature and the offices of the Governor of Oregon, governor, Oregon Secretary of State, secretary of state, and Oregon State Treasurer, treasurer of the ...

Oregon State Capitol
in Salem. Evidence suggests that massive quakes of 8 or more on the Richter scale have occurred historically in the
Cascadia subduction zone The Cascadia subduction zone is a convergent Convergent is an adjective for things that wikt:converge, converge. It is commonly used in mathematics and may refer to: *Convergent boundary, a type of plate tectonic boundary * Convergent (continue ...
off the Oregon coast, most recently in 1700 CE, and that others as strong as 9 on the Richter scale occur every 500 to 800 years. 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.


Watershed

The Willamette River drains a region of , which is 12 percent of the total area of Oregon. Bounded by the Coast Range to the west and the Cascade Range to the east, the river basin is about long and wide. Elevations within the watershed range from at Mount Jefferson in the Cascade Range to at the mouth on the Columbia River. Watersheds bordering the Willamette River basin are those of the Little Deschutes River to the southeast, the
Deschutes River Deschutes River may refer to: *Deschutes River (Oregon) **Little Deschutes River (Oregon), a tributary of the Deschutes River in Oregon *Deschutes River (Washington) * River De Chute in Maine