The Tualatin Valley is a farming and suburban region southwest of Portland, Oregon in the United States. The valley is formed by the meandering Tualatin River, a tributary of the Willamette River at the northwest corner of the Willamette Valley, east of the Northern Oregon Coast Range. Most of the valley is located within Washington County, separated from Portland by the Tualatin Mountains. Communities in the Tualatin Valley include Banks, Forest Grove, Hillsboro, Beaverton, Sherwood and Tualatin. In the early 19th century, the valley was inhabited by the Atfalati, a hunter-gatherer Kalapuyan band that spoke a dialect of Northern Kalapuyan. In the middle 19th century, the Atfalati lived in several villages in the valley, including Chakeipi. Early Euro-American settlers called the valley the "Twality Plains", a corruption of the name of the Atfalati tribe. Other early variations included Falatin, Nefalatine and Quality, with each translated as slow river to describe the Tualatin River, or may translate as land without trees.
The valley was one of the earliest settled farming regions in Oregon, as settlers began arriving in 1840. In the spring of 1847, Lawrence Hall filed the first land claim, comprising 640 acres, at Beaver Dam and constructed the first grist mill in the valley. In 1849 Thomas Hicklin Denney and his wife Berrilla built the first sawmill in the Beaverton area, leading to a boom in the timber industry; the lack of roads connecting the upper valley to the Willamette River became a hindrance to early settlers. In 1850, the Oregon Territory created the Portland & Valley Plank Road Company to build a road through the Tualatin Hills connecting Portland with Beaverton; the road was completed in 1860 after financial setbacks. According to Oregon historian Stewart Holbrook, the building of the plank road was the decisive event that allowed Portland to surpass its rival Oregon City for supremacy as the economic hub of the territory; the railroad was extended into the valley in 1868. The growth of agriculture in the valley was limited in the middle 20th century by the need for irrigation.
In 1966, the United States Bureau of Reclamation built the Tualatin Project, bringing additional water to many parts of the valley in the last federal reclamation project in the Pacific Northwest. In the second half of the 20th century the valley became suburbanized and now forms a distinct cultural area that rivals Portland itself in political and economic influence; the communities along the Tualatin Valley Highway, form a suburban corridor stretching west of Beaverton. Beaverton is famous as the location of the company's world-wide headquarters. Nike, along with Intel in Hillsboro, provide a large base of employment in the valley. Much of the valley is now within the Portland urban growth boundary, resulting in a suburban growth patterns that interspersed with remaining areas of orchards and farm fields. Most of the communities in the valley are served by the Portland-area mass transit agency. In 1998, the MAX Light Rail system was extended from Portland into the valley as far as Hillsboro.
The valley is traversed by the Tualatin River and is bordered on the north and east by the Tualatin Mountains, a spur of the Northern Oregon Coast Range. The latter range comprises the valley's western border. To the south lie the Chehalem Mountains, separating the region from the main Willamette Valley; the Tualatin River flows from the west to the east and leaves the valley in the southeast at West Linn in Clackamas County. Tualatin Valley's geographical center is located southeast of Hillsboro, the general elevation of the valley is 180 feet above sea-level. Tualatin Plains
Portland is the largest and most populous city in the U. S. state of Oregon and the seat of Multnomah County. It is a major port in the Willamette Valley region of the Pacific Northwest, at the confluence of the Willamette and Columbia rivers; as of 2017, Portland had an estimated population of 647,805, making it the 26th-largest city in the United States, the second-most populous in the Pacific Northwest. 2.4 million people live in the Portland metropolitan statistical area, making it the 25th most populous MSA in the United States. Its Combined Statistical Area ranks 18th-largest with a population of around 3.2 million. 60% of Oregon's population resides within the Portland metropolitan area. Named after Portland, the Oregon settlement began to be populated in the 1830s near the end of the Oregon Trail, its water access provided convenient transportation of goods, the timber industry was a major force in the city's early economy. At the turn of the 20th century, the city had a reputation as one of the most dangerous port cities in the world, a hub for organized crime and racketeering.
After the city's economy experienced an industrial boom during World War II, its hard-edged reputation began to dissipate. Beginning in the 1960s, Portland became noted for its growing progressive political values, earning it a reputation as a bastion of counterculture; the city operates with a commission-based government guided by a mayor and four commissioners as well as Metro, the only directly elected metropolitan planning organization in the United States. The city government is notable for its land-use investment in public transportation. Portland is recognized as one of the world's most environmentally conscious cities because of its high walkability, large community of bicyclists, farm-to-table dining, expansive network of public transportation options, over 10,000 acres of public parks, its climate is marked by cool, rainy winters. This climate is ideal for growing roses, Portland has been called the "City of Roses" for over a century. During the prehistoric period, the land that would become Portland was flooded after the collapse of glacial dams from Lake Missoula, in what would become Montana.
These massive floods occurred during the last ice age and filled the Willamette Valley with 300 to 400 feet of water. Before American pioneers began arriving in the 1800s, the land was inhabited for many centuries by two bands of indigenous Chinook people—the Multnomah and the Clackamas; the Chinook people occupying the land were first documented in 1805 by Meriwether Lewis and William Clark. Before its European settlement, the Portland Basin of the lower Columbia River and Willamette River valleys had been one of the most densely populated regions on the Pacific Coast. Large numbers of pioneer settlers began arriving in the Willamette Valley in the 1830s via the Oregon Trail, though life was centered in nearby Oregon City. In the early 1840s a new settlement emerged ten miles from the mouth of the Willamette River halfway between Oregon City and Fort Vancouver; this community was referred to as "Stumptown" and "The Clearing" because of the many trees cut down to allow for its growth. In 1843 William Overton saw potential in the new settlement but lacked the funds to file an official land claim.
For 25 cents, Overton agreed to share half of the 640-acre site with Asa Lovejoy of Boston. In 1845 Overton sold his remaining half of the claim to Francis W. Pettygrove of Maine. Both Pettygrove and Lovejoy wished to rename "The Clearing" after their respective hometowns; this controversy was settled with a coin toss that Pettygrove won in a series of two out of three tosses, thereby providing Portland with its namesake. The coin used for this decision, now known as the Portland Penny, is on display in the headquarters of the Oregon Historical Society. At the time of its incorporation on February 8, 1851, Portland had over 800 inhabitants, a steam sawmill, a log cabin hotel, a newspaper, the Weekly Oregonian. A major fire swept through downtown in August 1873, destroying twenty blocks on the west side of the Willamette along Yamhill and Morrison Streets, causing $1.3 million in damage. By 1879, the population had grown to 17,500 and by 1890 it had grown to 46,385. In 1888, the city built the first steel bridge built on the West Coast.
Portland's access to the Pacific Ocean via the Willamette and Columbia rivers, as well as its easy access to the agricultural Tualatin Valley via the "Great Plank Road", provided the pioneer city with an advantage over other nearby ports, it grew quickly. Portland remained the major port in the Pacific Northwest for much of the 19th century, until the 1890s, when Seattle's deepwater harbor was connected to the rest of the mainland by rail, affording an inland route without the treacherous navigation of the Columbia River; the city had its own Japantown, for one, the lumber industry became a prominent economic presence, due to the area's large population of Douglas Firs, Western Hemlocks, Red Cedars, Big Leaf Maple trees. Portland developed a reputation early in its history as a gritty port town; some historians have described the city's early establishment as being a "scion of New England. In 1889, The Oregonian called Portland "the most filthy city in the Northern States", due to the unsanitary sewers and gutters, and, at the turn of the 20th century, it was considered one of the most dangerous port cities in the world.
The city housed a large number of saloons
Whatcom County, Washington
Whatcom County is a county located in the U. S. state of Washington. As of the 2010 census, the population was 201,140, it is bordered by Canada on the north, Okanogan County on the east, Skagit County on the south, the Strait of Georgia on the west. The county seat and largest city is Bellingham; the county was created from Island County by the Washington Territorial Legislature in March 1854. It included the territory of present-day San Juan and Skagit Counties, which were organized after additional settlement, its name derives from the Lummi word Xwotʼqom, meaning "noisy water."Whatcom County comprises the Bellingham, WA Metropolitan Statistical Area. Whatcom County's northern border is the Canada–US border with the Canadian province of British Columbia. Adjoining the county on the north are five of metropolitan Vancouver's suburbs, White Rock, Langley, and, in the central Fraser Valley, Abbotsford. Several shopping malls and other services in Bellingham and elsewhere in the county are geared to cross-border shopping and recreation.
The five crossing points are two at Blaine. The Whatcom County area has known human habitation for at least twelve millenia. At least three aboriginal tribes have been identified in the area: Lummi and Semiahmoo; this area was part of the Oregon Country at the start of the nineteenth century, inhabited both by fur prospectors from Canada, Americans seeking land for agricultural and mineral-extraction opportunities. Unable to resolve which country should control this vast area, the Treaty of 1818 provided for joint control. In 1827 the Hudson's Bay Company established Fort Langley near present Lynden. By 1843, the Provisional Government of Oregon had been established, although at first there were questions as to its authority and extent. During its existence, that provisional government formed the area north of the Columbia River first into the Washington Territory, into two vast counties: Clark and Lewis. In 1852, a portion of Lewis County was partitioned off to form Thurston County, in 1853 a portion of the new county was partitioned off to form Island County.
The Washington Territory was formed as a separate governing entity in 1853. In 1854, that legislature carved several counties out of the existing counties, including Whatcom County on March 9, 1854, with area taken from Island County; the original county boundary was reduced in 1873 by the formation of San Juan County, again in 1883 by the formation of Skagit County. A Nooksack chief is the namesake of Whatcom County, taken from the word in the Nooksack language for "noisy water."In 1855 the settlers erected a blockhouse west of Whatcom Creek, to protect against forays from the aboriginal inhabitants who were attempting to defend their homelands. That year the Treaty of Point Elliott was signed, which assigned the Lummi and Semiahmoo peoples a greatly-restricted reserved area; the short-lived Fraser Canyon Gold Rush caused a short-term increase in the county's population, which swelled to over 10,000 before the bubble burst. In 1857 the federal government began the field work necessary to establish the national border between the United States and Canada, agreed on as the forty-ninth parallel in this area, which would mark the north line of Whatcom County.
As the work moved east, several of the workers chose to remain in the area as settlers. According to the U. S. Census Bureau, the county has a total area of 2,503 square miles, of which 2,107 square miles is land and 397 square miles is covered by water; the county includes Lake Whatcom. Physiographically, Whatcom County is an extension of the Fraser Valley or "Lower Mainland" area of British Columbia the lowland delta plain of the Fraser River. At some periods in the past, one of the Fraser River's lower arms entered Bellingham Bay near Bellingham via what is now the mouth of the Nooksack River. A small part of the county, Point Roberts, about 5 square miles, is an extension of the Tsawwassen Peninsula, bisected by the Canada–US border along the 49th parallel; the highest point in the county is the peak of the active volcano Mount Baker at 10,778 feet above sea level. The lowest points are at sea level along the Pacific Ocean. Mount Baker National Recreation Area Mount Baker-Snoqualmie National Forest North Cascades National Park Ross Lake National Recreation Area Pacific Northwest National Scenic Trail Birch Bay State Park Lake Terrell Wildlife Refuge Larrabee State Park Lookout Mountain Lummi Island Stewart Mountain Lake Whatcom Watershed Interstate 5 connecting with Seattle, Sacramento, Los Angeles, San Diego and points south.
SR 20 connecting US 101 and Sidney, British Columbia with Newport, Washington via the North Cascades Highway. Farthest north highway thru the Cascade Mountains in USA. Note that this highway does not connect to most of Whatcom County – Instead, a person would have to travel south to Sedro-Woolley in Skagit County to connect to Highway 20. Alaska Marine Highway connecting Alaska highways to the Interstate Highway System. Okanogan County – east Skagit County – south San Juan County – southwest Metro Vancouver – north Fraser Valley Regional District, British Columbia – north Cowichan Val
Clark County, Washington
Clark County is a county in the southwestern part of the U. S. state of Washington, the southernmost county in Washington. As of the 2010 census, the population was 425,363, making it Washington's fifth-most populous county, its county seat and largest city is Vancouver. It was the first county in Washington, named after William Clark of the Clark Expedition, it was created by the provisional government of Oregon Territory on August 20, 1845, at that time covered the entire present-day state. Clark County is the third most populous county in the Portland-Vancouver-Hillsboro, OR-WA Metropolitan Statistical Area, is located across the Columbia River from Portland. Clark County began as the District of Vancouver on July 27, 1844, it included all the land north of the Columbia River, west of the Rocky Mountains, south of Alaska. In 1845 the provisional government changed its name to Vancouver County. At that time it stretched from the Columbia River to 54 degrees 40 minutes North Latitude in what is now British Columbia.
On June 15, 1846 the United States Senate approved the present boundary between the U. S. and Canada at the 49th Parallel. On August 13, 1848, President James K. Polk signed an act creating the entire region as the Oregon Territory. On September 3, 1849, the Oregon Territorial Legislature modified the borders again and changed its name to Clarke County in honor of explorer William Clark. At this time it included all of present-day Washington and continued to be divided and subdivided until reaching its present area in 1880, it was not until 1925. In September 1902 the Yacolt Burn, the largest fire in state history, began in neighboring Skamania County and swept west along a 12-mile front to Yacolt, nearly engulfing the town. Salvaging the remaining timber was a lucrative industry for a time. According to the U. S. Census Bureau, the county has a total area of 656 square miles, of which 629 square miles is land and 27 square miles is water, it is the fifth-smallest county in Washington by land area.
Clark County is surrounded on two sides by the Columbia River and on the north by the North Fork of the Lewis River. The East Fork of the Lewis River and the Washougal River cut across the county; the largest stream arising within the county is Salmon Creek, which terminates at Vancouver Lake before flowing into the Columbia River. Like most of Oregon and Washington south of Puget Sound into the Willamette Valley the landscape and climate of Clark County are determined by its placement between the volcanic Pacific Coast and Cascade Ranges, where glaciation helped form a U-shaped valley which meets the river valley of the Columbia River as it leaves the Columbia River Gorge. Volcanic andisol soils are common, with fertile mollisols in the lower areas; the central and southwest areas of the county are flat floodplains, sculpted by torrents of prehistoric Lake Missoula. A series of dramatic floods known as the Missoula Floods took place 15,000 - 13,000 years ago, as several ice dams melted, forming a series of low steps such as the "Heights", "Mill Plain", "Fourth Plain" and "Fifth Plain".
Clark County's Köppen climate classification is "Csb." Many lakes border the river including Vancouver Lake. Eastern and northern Clark County contain forested foothills of the Cascade Mountains, rising to an elevation of 4,000 feet on the border with Skamania County. Larch Mountain is the county's highest free-standing peak. Flora and fauna of the region include the normal ecological succession from lowland big leaf maple and western red cedar through Garry oak on up through fire-dependent species such as lodgepole pine and Douglas fir, as well as grand fir, silver fir and other species common to Gifford Pinchot National Forest. In addition to a wide variety of birds including great blue heron, raptors such as barred owl, red-tailed hawk and bald eagle and others, the native streams are home to various species of salmon and the Vancouver Trout Hatchery. Larger mammals include black-tailed deer, raccoon and invasive opossum. Common foods used by the indigenous people such as the Klickitat tribe and Chinook included salmon and Camassia quamash.
Mount Hood, Mount Saint Helens and Mount Adams are all visible from Clark County, cold winter winds through the Columbia River Gorge bring freezing rain and a coating of glaze ice or clear ice known locally as a "silver thaw," in southeastern areas of the county closest to the gorge. The counterpart to this are warm winds from the southwest known locally as the "Pineapple Express". Spring thaws can swell county waterways, with two of the more destructive floods being those of the Columbia River in June 1894 and May, 1948; the 1948 Memorial Day flood topped the Interstate Bridge's support piers and destroyed nearby Vanport, Oregon. Construction of The Dalles Dam and destruction of Celilo Falls are credited with a decrease in such floods. Significant windstorms in Clark County include the Columbus Day windstorm of October 12, 1962, an April 6, 1972 tornado which rated F3 on the Fujita scale, striking a local school. A "Friday the 13th" storm in November 1981 brought winds up to 70 miles per hour, with other storms including the inauguration day storm of January 20, 1993, the Guadalupe Day storm of December 12, 1995 and small tornado on January 10, 2008, which destroyed a boath
Hood River County, Oregon
Hood River County is a county located in the U. S. state of Oregon. As of the 2010 census, the population was 22,346; the county seat is Hood River. The county was established in 1908 and is named for the Hood River, a tributary of the Columbia River. Hood River County comprises OR Micropolitan Statistical Area; the Hood River Valley is a top producer of apples and cherries and is known for its famous Fruit Loop driving tour that stops at family farms and fruit stands. Situated between Mount Hood and the Columbia River in the middle of the Columbia River Gorge, Hood River County is a popular destination for outdoor enthusiasts, such as windsurfers, mountain-bikers, hikers and many more; the first permanent settlers in present-day Hood River County filed a donation land claim in 1854. The first school was built in 1863 and a road from The Dalles was completed in 1867. By 1880 there were 17 families living in the valley. By the latter part of the nineteenth century farmers of Japanese, Finnish and French ethnicity had settled in the valley.
At the turn of the twentieth century, the people of the Hood River region in the northwest portion of Wasco County expressed a desire for political separation from the parent county. The passage of a statewide initiative established Hood River as the thirty-fourth county of the state, it was made official by a governor's proclamation on June 23, 1908. The Columbia River Highway was completed in 1922 from Portland to The Dalles, improving access between both those cities as well as to Hood River. In response to controversy surrounding county approval of locating a destination resort at Cooper Spur ski area on Mount Hood, on November 5, 2003 62% of the voters approved a measure requiring voter approval on residential developments of 25 units or more on land zoned for forest use. Opponents would end up in court. Hood River County is 533 square miles, of which 522 square miles is land and 11 square miles is water, it is the second-smallest county in Oregon by area. Elevation ranges from 60 feet above sea level at Cascade Locks in the northwest to 11,235 feet at the summit of Mt. Hood, the highest point in Oregon.
The County lies in a transition zone in the Columbia River Gorge between the temperate rain forest of the Cascade range and dry desert of eastern Oregon. Precipitation varies by longitude and elevation. Annual precipitation averages over 76 inches in Cascade Locks, but is less than 31 inches in the City of Hood River. At the highest reaches of the County on Mt. Hood precipitation can be up to 150 inches annually; the Gorge can have a moderating effect on air temperatures in the County near the Columbia River when maritime air moves in from the west. Major easterly flows, can cause extreme cold conditions as cold air moves west through the Gorge. Winds are from the west in the summer, resulting in strong and consistent winds on the Columbia River at Hood River County, making Hood River a world-renowned wind surfing location. Winter winds can blow from either the east or the west and can be of sufficient force to result in widespread damage. Hood River County contains the entirety of the 217,337 acres Hood River watershed, which covers nearly two-thirds of the county.
This watershed includes four main sub-basins: the West Fork Hood River, the Middle Fork Hood River, the East Fork Hood River, the Hood River Mainstem. Sixty percent, or 209,385 acres, of the County is federal land managed by the Mt. Hood National Forest. Another 31,000 acres, or 8.8 percent, is forestland managed by Hood River County. The State of Oregon owns 3,894 acres within the County. Weyerhaeuser Company became a major private landowner in 2013 after purchasing Longview Timber LLC, including its forest holdings in Hood River County. 25,817 acres, over seven percent of the County, is managed as private farmland. As of 2012 there were 554 farms, with a medium farm size of 19 acres. Multnomah County - west Clackamas County - southwest Wasco County - southeast Klickitat County, Washington - northeast Skamania County, Washington - north Badger Creek Wilderness Mark O. Hatfield Wilderness Mount Hood Wilderness Columbia River Gorge National Scenic Area At the time of the census 11.8 percent of a total of 9,271 housing units were vacant.
Of the 8,173 occupied housing units, 62.9 percent were owner-occupied. Median household income was $51,307 and median income for a family was $57,644; as of the 2010 census 2,235 persons, or 10.1 percent of the population, lived in poverty. Of the 20,258 people in the population that are five years and older, 25.6 percent speak Spanish or Spanish Creole, 69 percent of this group speak English less than "very well." As of the 2010 United States Census, there were 22,346 people, 8,173 households, 5,659 families residing in the county. The population density was 42.8 inhabitants per square mile. There were 9,271 housing units at an average density of 17.8 per square mile. The racial makeup of the county was 83.1% white, 1.4% Asian, 0.8% American Indian, 0.5% black or African American, 0.2% Pacific islander, 10.9% from other races, 3.2% from two or more races. Those of Hispanic or Latino origin made up 29.5% of the population. In terms of ancestry, 16.7% were German, 10.6% were English, 9.8% were Irish, 3.8% were American.
Of the 8,173 households, 35.9% had children under the age of 18 living with them, 55.4% were married couples living together, 9.3% had a female householder with no husband present, 30.8% were non-families, 23.8% of all households were made up of individuals. The average household size was
The Columbia River is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of Canada, it flows northwest and south into the US state of Washington turns west to form most of the border between Washington and the state of Oregon before emptying into the Pacific Ocean. The river is 1,243 miles long, its largest tributary is the Snake River, its drainage basin is the size of France and extends into seven US states and a Canadian province. The fourth-largest river in the United States by volume, the Columbia has the greatest flow of any North American river entering the Pacific; the Columbia and its tributaries have been central to the region's culture and economy for thousands of years. They have been used for transportation since ancient times, linking the region's many cultural groups; the river system hosts many species of anadromous fish, which migrate between freshwater habitats and the saline waters of the Pacific Ocean. These fish—especially the salmon species—provided the core subsistence for native peoples.
In the late 18th century, a private American ship became the first non-indigenous vessel to enter the river. In the following decades, fur trading companies used the Columbia as a key transportation route. Overland explorers entered the Willamette Valley through the scenic but treacherous Columbia River Gorge, pioneers began to settle the valley in increasing numbers. Steamships along the river linked facilitated trade. Since the late 19th century and private sectors have developed the river. To aid ship and barge navigation, locks have been built along the lower Columbia and its tributaries, dredging has opened and enlarged shipping channels. Since the early 20th century, dams have been built across the river for power generation, navigation and flood control; the 14 hydroelectric dams on the Columbia's main stem and many more on its tributaries produce more than 44 percent of total US hydroelectric generation. Production of nuclear power has taken place at two sites along the river. Plutonium for nuclear weapons was produced for decades at the Hanford Site, now the most contaminated nuclear site in the US.
These developments have altered river environments in the watershed through industrial pollution and barriers to fish migration. The Columbia begins its 1,243-mile journey in the southern Rocky Mountain Trench in British Columbia. Columbia Lake – 2,690 feet above sea level – and the adjoining Columbia Wetlands form the river's headwaters; the trench is a broad and long glacial valley between the Canadian Rockies and the Columbia Mountains in BC. For its first 200 miles, the Columbia flows northwest along the trench through Windermere Lake and the town of Invermere, a region known in British Columbia as the Columbia Valley northwest to Golden and into Kinbasket Lake. Rounding the northern end of the Selkirk Mountains, the river turns south through a region known as the Big Bend Country, passing through Revelstoke Lake and the Arrow Lakes. Revelstoke, the Big Bend, the Columbia Valley combined are referred to in BC parlance as the Columbia Country. Below the Arrow Lakes, the Columbia passes the cities of Castlegar, located at the Columbia's confluence with the Kootenay River, Trail, two major population centers of the West Kootenay region.
The Pend Oreille River joins the Columbia about 2 miles north of the US–Canada border. The Columbia enters eastern Washington flowing south and turning to the west at the Spokane River confluence, it marks the southern and eastern borders of the Colville Indian Reservation and the western border of the Spokane Indian Reservation. The river turns south after the Okanogan River confluence southeasterly near the confluence with the Wenatchee River in central Washington; this C‑shaped segment of the river is known as the "Big Bend". During the Missoula Floods 10,000 to 15,000 years ago, much of the floodwater took a more direct route south, forming the ancient river bed known as the Grand Coulee. After the floods, the river found its present course, the Grand Coulee was left dry; the construction of the Grand Coulee Dam in the mid-20th century impounded the river, forming Lake Roosevelt, from which water was pumped into the dry coulee, forming the reservoir of Banks Lake. The river flows past The Gorge Amphitheatre, a prominent concert venue in the Northwest through Priest Rapids Dam, through the Hanford Nuclear Reservation.
Within the reservation is Hanford Reach, the only US stretch of the river, free-flowing, unimpeded by dams and not a tidal estuary. The Snake River and Yakima River join the Columbia in the Tri‑Cities population center; the Columbia makes a sharp bend to the west at the Washington–Oregon border. The river defines that border for the final 309 miles of its journey; the Deschutes River joins the Columbia near The Dalles. Between The Dalles and Portland, the river cuts through the Cascade Range, forming the dramatic Columbia River Gorge. No other rivers except for the Klamath and Pit River breaches the Cascades—the other rivers that flow through the range originate in or near the mountains; the headwaters and upper course of the Pit River are on the Modoc Plateau. In contrast, the Columbia cuts through the range nearly a thousand miles from its source in the Rocky Mountains; the gorge is known
The Willamette River 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 long, lying 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 and the state's largest city, which surrounds the Willamette's mouth at the Columbia. Created by plate tectonics about 35 million years ago and subsequently altered by volcanism and erosion, the river's drainage basin was 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. 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, was thus the destination of many 19th-century pioneers traveling west along the Oregon Trail.
The river was an important transportation route in the 19th century, although Willamette Falls, just upstream from Portland, was a major barrier to boat traffic. In the 21st century, major highways follow the 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, 13 of which are operated by the U. S. Army Corps of Engineers; the dams are used to produce hydroelectricity, to maintain reservoirs for recreation, to prevent flooding. 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 and the river was named as one of 14 American Heritage Rivers in 1998; the upper tributaries of the Willamette originate in the mountains south and southeast of Eugene, Oregon. Formed by the confluence of the Middle Fork Willamette River and the Coast Fork Willamette River near Springfield, the main stem Willamette meanders north for 187 miles to the Columbia River.
The river's two most significant course deviations occur at Newberg, where it turns east, about 18 miles downstream 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. Used for navigation purposes, these channels are managed by the U. S. federal government. The main channel, 40 feet deep and varies in width from 600 to 1,900 feet, enters the Columbia about 101 miles from the larger river's mouth on the Pacific Ocean; the channel forms the primary navigational conduit for Portland's harbor and riverside industrial areas. The smaller Multnomah Channel, a distributary, is 21 miles long, about 600 feet wide, 40 feet deep, it ends about 14.5 miles further downstream on the Columbia, near St. Helens in Columbia County. Proposals have been made for deepening the Multnomah Channel to 43 feet in conjunction with 103.5 miles 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.
The river was shortened by 40 percent in the stretch between Harrisburg and Albany. Interstate 5 and three branches of Oregon Route 99 are the two major highways that follow the river for its entire length. Communities along the main stem include Eugene in Lane County. Significant tributaries from source to mouth include the Middle and Coast forks and the McKenzie, Long Tom, Calapooia, Luckiamute, Molalla and Clackamas rivers. Beginning at 438 feet above sea level, the main stem descends 428 feet between source and mouth, or about 2.3 feet per mile. The gradient is steeper from the source to Albany than it is from Albany to Oregon City. At Willamette Falls, between West Linn and Oregon City, the river plunges about 40 feet. For the rest of its course, the river is low-gradient and is affected by Pacific Ocean tidal effects from the Columbia; the main stem of the Willamette varies in width from about 330 to 660 feet. With an average flow at the mouth of about 37,400 cubic feet per second, 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 season to season, averaging about 8,200 cubic feet per second in August to more than 79,000 cubic feet per second in December. The U. S. Geological Survey operates five stream gauges along the river, at Harrisburg, Albany and Portland; the average discharge at the lowermost gauge, near the Morrison Bridge in Portland, was 33,220 cubic feet per second