Уилламет өзені: Орегон штатының маңызды саласы

187 mile Columbia River tributary in northwest Oregon, US

The Willamette River (/audio=En Willamette River. oga//w//ᵻ/'/l//æ//m//ᵻ//t/ wilAMit) 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 mile (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, which surrounds the Willamette's mouth at the Columbia. Originally created by plate tectonics about 35 million years ago and subsequently altered by volcanism and erosion, the river's drainage 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. 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 it 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, and roads cross the main stem on approximately 30 different bridges. 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 between Marion County and Polk County north of Salem and Keizer, and Canby Ferry 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 (USACE). The dams are used primarily to produce hydroelectricity, to maintain reservoirs for recreation, and to prevent flooding. The river and its tributaries support 60 fish species, including many species of salmon and trout; this is despite the dams, other alterations, and pollution (especially on the river's lower reaches). 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 generally north for 187 mile (301 km) to the Columbia River. The river's two most significant course deviations occur at Newberg, where it turns sharply east, and about 18 mile (29 km) 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, which is the primary navigational conduit for Portland's harbor and riverside industrial areas, is 40 feet (12 m) deep and varies in width from , although the river broadens to 2000 feet (610 m) in some of its lower reaches. Proposals have been made for deepening the Multnomah Channel to 43 feet (13 m) in conjunction with roughly 103.5 mile (167 km) of tandem maintained navigation on the Columbia River. 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 Springfield and Eugene in Lane County; Harrisburg in Linn County; Corvallis in Benton County; Albany in Linn and Benton counties; Independence in Polk County; 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. The gradient is slightly 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 (12 m). and contributes 12 to 15 percent of the total flow of the Columbia River. 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 river below Willamette Falls, 26.5 mile (43 km) from the mouth, is affected by semidiurnal tides, and gauges have detected reverse flows (backwards river flows) below Ross Island at RM 15 (RK 24). The National Weather Service issues tide forecasts for the river at the Morrison Bridge.

The Willamette River basin was created primarily by plate tectonics and volcanism and was altered by erosion and sedimentation, including deposits from enormous glacial floods as recent as 13,000 years ago. The oldest rocks beneath the Willamette Valley are the Siletz River Volcanics. About 35 million years ago, these rocks were subducted by the Farallon Plate beneath the North American Plate, creating the forearc basin that would later become the Willamette Valley. The valley was initially part of the continental shelf, rather than a separate inland sea. Many layers of marine deposits formed in the forearc basin and cover the older Siletz River Volcanics. Later deposits covered the basalt with up to 1000 feet (305 m) of silt in the Portland and Tualatin basins. 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, and braided rivers created alluvial fans spreading down from the east.]] 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. 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. Before being partly chipped away and removed, the largest of these originally weighed about In 1993, the Scotts Mills earthquake—the largest recent earthquake in the valley, measuring 5.6 on the Richter scale—was centered near Scotts Mills, about 34 mile (55 km) south of Portland. It caused $30 million in damage, including harm to 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 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. About 2.5 million people lived in the Willamette River basin as of 2010, about 65 percent of the population of Oregon. As of 2009, the basin contained 20 of the 25 most populous cities in Oregon. These cities include Springfield, Eugene, Corvallis, Albany, Salem, Keizer, Newberg, Oregon City, West Linn, Milwaukie, Lake Oswego, and Portland. Other cities in the watershed (but not on the main stem river) with populations of 20,000 or more are Gresham, Hillsboro, Beaverton, Tigard, McMinnville, Tualatin, Woodburn, and Forest Grove. In 1987, the U. S. Secretary of the Interior designated of the watershed in Benton County as a National Natural Landmark. This area is the Willamette Floodplain, the largest remaining unplowed native grassland in the North Pacific geologic province, which encompasses most of the Pacific Northwest coast.

For at least 10,000 years, a variety of indigenous peoples populated the Willamette Valley. These included the Kalapuya, the Chinook, and the Clackamas. The territory of the Clackamas encompassed the northeastern portion of the basin, including the Clackamas River (with which their name is shared). Although it is unclear exactly when, the territory of the Chinook once 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 Kalapuyan speaking Yamhill and Atfalati (Tualatin) (both Northern Kalapuya), Central Kalapuya like the Santiam, Muddy Creek (Chemapho), Long Tom (Chelamela), Calapooia (Tsankupi), Marys River (Chepenafa) and Luckiamute, and the Yoncalla or Southern Kalapuya, as well other tribes such as the Chuchsney Tufti, Siuslaw and Molala. However, Native American languages in Oregon were very similar, so the name may also be derived from Kalapuya dialects. 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. In that time period, the Clackamas' tribal population was roughly 1,800. The U. S. Census Bureau estimated that the Chinook population was nearly 5,000, 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 south in the Willamette Valley. The total native population was estimated at 15,000. practiced slavery, and had a well defined caste system.

The Willamette River first appeared in written records in 1792, when it was observed by British Lieutenant William Robert Broughton of the Vancouver Expedition, led by George Vancouver.

The 1805 1806 Lewis and Clark Expedition originally missed the mouth of the Willamette. On their return journey, only after receiving directions from natives along the Sandy River did the explorers learn about their oversight. William Clark returned down the Columbia and entered the Willamette River in April 1806. The Siskiyou Trail (or California Oregon Trail) originally developed by Indigenous people, was used to reach farther south. This trail, over 600 mile (966 km) long, stretched from the mouth of the Willamette River near present day Portland south through the Willamette Valley, crossing the Siskiyou Mountains, and south through the Sacramento Valley to San Francisco. In 1812, William Henry and Alfred Seton paddled up from Fort Astoria (PFC) on the Columbia River into the mouth of the Willamette, continued on until the falls portage (present day Oregon City) and finished their journey at a flattening of both banks, the later site of Champoeg. A first trading post was established. By early 1813, William Wallace and John C. Halsey established a second outpost, Wallace House, farther south, north of present day Salem. By the end the War of 1812, the NWC acquired the PFC. Free trappers Registre Bellaire, John Day and Alexander Carson hunted and traded furs during the winter of 1813 14 along the Willamette. About thirty NWC employees were stationed at the Champoeg post, now called the Willamette Trading Post, along with freemen housed in two huts and Kalapuya nearby. Nez Perce and Cayuse warned the NWC to stay out of the Willamette Valley hunting grounds. Skirmishes went on for several years over fishing and hunting grounds contended by several groups. By the winter of 1818 19, Thomas McKay led a hunting brigade farther south towards the sources of the Willamette River and reached the upper Umpqua River. More violent skirmishes were fought. Most brigade members returned to Fort George (formerly called Fort Astoria). Louis LaBonté, Joseph Gervais, Étienne Lucier, Louis Kanota, and Louis Pichette (dit DuPré) remained in the Willamette Valley as free trappers. Meanwhile, in 1821 the HBC merged with the NWC. In 1825 a new Fort Vancouver headquarters was built on the north shore of the Columbia closer to the Willamette, and Fort George was closed. Alexander Roderick McLeod traveled up the Willamette in 1826 and 1827, to the Umpqua and the Rogue rivers. In 1829 Lucier established a land claim near the Champoeg trading post and started to settle, soon joined by Gervais (1831), Pierre Belleque (1833) and 77 French Canadian settlers by 1836. By 1843, approximately 100 newcomer families lived in the vicinity of the Willamette on a section referred to as French Prairie. By 1841, members of the United States Exploring Expedition came through the Siskiyou Trail. They noted extensive salmon fishing by natives at Willamette Falls, much like that at Celilo Falls on the Columbia River. 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. Many of these emigrants followed the Oregon Trail, a 2170 mile (3492 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, to reach the Willamette Valley. Starting in the 1830s, Oregon City developed near Willamette Falls. It was incorporated in 1844, becoming the first city west of the Rocky Mountains to have that distinction. John McLoughlin, the Hudson's Bay Company (HBC) superintendent of the Columbia District, was one of the major contributors to the founding of the town in 1829. McLoughlin attempted to persuade the HBC (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. Oregon City prospered because of the lumber and grist 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. After Portland was incorporated in 1851, quickly growing into Oregon's largest city, Oregon City gradually lost 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. 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. Any boats whose owners found it absolutely necessary to get past the falls had to be portaged. This led to competition for business among steam portage companies. 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. Since 2011, the Willamette Falls Locks have been inactive. 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. 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. They were first led off their traditional lands to the Willamette Valley, but soon were marched to the Coast Indian Reservation. In 1855, Joel Palmer, an Oregon legislator, negotiated a treaty with the Willamette Valley tribes, who, although unhappy with the treaty, ceded their lands to non natives. The natives were then relocated by the government to a part of the Coast Reservation that later became the Grande Ronde Reservation. Rockwell's survey was extremely detailed, including 17,782 hydrographic soundings. His work helped open the port of Portland to commerce. In the second half of the 19th century, the USACE dredged channels and built locks and levees in the Willamette's watershed. Although products such as lumber were often transported on an existing network of railroads in Oregon, these advances in navigation helped businesses deliver more goods to Portland, feeding the city's growing economy. Trade goods from the Columbia basin north of Portland could also be transported southward on the Willamette due to the deeper channels made at the Willamette's mouth.

By 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 walls to protect its downtown sector. Most of them do not have fish ladders. 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. The Oregon State Legislature established the 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. By 2007 the Greenway had grown to include more than 170 separate land parcels, including 10 state parks. Four years later, the National Park Service added the Willamette water trail—expanded to 217 mile (349 km) to include some of the major tributaries—to its list of National Water Trails. The water trail system is meant to protect and restore waterways in the United States and enhance recreation on and near them. A 1991 agreement between the City of Portland and the State of Oregon to dramatically reduce combined sewer overflows (CSOs) led to Portland's Big Pipe Project. The project, part of a related series of Portland CSO projects completed in late 2011 at a cost of $1.44 billion, separates the city's sanitary sewer lines from storm water inputs that sometimes overwhelmed the combined system during heavy rains. When that occurred, some of the raw sewage in the system flowed into the river instead of into the city's wastewater treatment plant. The Big Pipe project and related work reduces CSO volume on the lower river by about 94 percent. In June 2014, Dean Hall became the first person to swim the entire length of the Willamette River. He swam 184 mile (296 km) from Eugene to the river mouth in 25 days.

There are more than 20 major dams on the Willamette's tributaries, as well as a complex series of levees and channels to control the river's flow. The only dam on the Willamette's main stem 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. The locks at Willamette Falls were completed in 1873. Elsewhere on the main stem, numerous minor flow regulation structures force the river into a narrower and deeper channel to facilitate navigation and flood control. Of those 13, 9 produce hydropower. A relatively small of amount of the water stored in the reservoirs is used for irrigation. Cougar Dam on the South Fork McKenzie River and Detroit Dam on the North Santiam River are the two tallest dams in the Willamette River basin. Detroit Dam is 463 feet (141 m) high and stores of water. Lookout Point Dam on the Middle Fork Willamette River, forming Lookout Point Lake, has the largest water storage capacity, at The other 11 dams are Big Cliff on the North Santiam River; Green Peter and Foster on the Santiam River; Cougar on the South Fork McKenzie River; Blue River on the Blue River; Fern Ridge on the Long Tom River; Hills Creek and Dexter on the Middle Fork Willamette River; Fall Creek on Fall Creek; Cottage Grove on the Coast Fork Willamette River, and Dorena on the Row River. Endangered species listings and a subsequent lawsuit by Willamette Riverkeeper led to a plan to improve fish passage and take other actions to help native fish recover in 2008. Since then, work has proceeded slowly, and the Corps of Engineers, citing engineering difficulties and cost, may not meet the original agreed upon deadline of 2023 for a system of effective remedies.

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. 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. The Ross Island Bridge carries U. S. Route 26 (Mount Hood Highway) over the river at RM 14 (RK 23). It is one of 10 highway bridges crossing the river in Portland. The 3700 feet (1128 m) bridge is the only cantilevered deck truss in Oregon. Tilikum Crossing is a 1720 feet (524 m) cable stayed bridge that carries public transit, bicycles, and pedestrians, but no cars or trucks, over the river. It opened for general use on September 12, 2015, becoming the first new bridge built across the river in the Portland metropolitan area since 1973. Farther downstream is the oldest remaining highway structure over the Willamette, the Hawthorne Bridge, built in 1910. It is the oldest vertical lift bridge in operation in the United States and the oldest highway bridge in Portland. It is also the busiest bicycle and transit bridge in Oregon, with over 8,000 cyclists and 800 TriMet buses (carrying about 17,400 riders) daily. It carries trains on its lower deck, MAX (Metropolitan Area Express) light rail trains and motorized vehicles on its upper deck, and foot and bicycle traffic on a cantilevered walkway attached to the lower deck. When small ships must pass under the bridge, its double vertical lift span can raise a lower railway deck without disturbing traffic on the upper deck. Operators can raise both decks as high as 163 feet (50 m) above the water. The Steel Bridge is "believed to be the world's only double lift span that can raise its lower deck independently of the upper deck." Farther downstream, the St. Johns Bridge, a steel suspension bridge built in 1931, replaced the last of the Willamette River ferries in Portland. At about RM 6 (RK 10), it carries the U. S. Route 30 Bypass. The bridge has two Gothic towers supporting the span. The adjacent park and neighborhood of Cathedral Park are named after the Gothic Cathedral like appearance of the bridge towers. It is the tallest bridge in Portland, with 400 feet (122 m) tall towers and a 205 feet (62 m) navigational clearance. The greatest Willamette River flood in recorded history began in 1861, well before the construction of dams in the watershed. This flood destroyed the town of Linn City. When the flood ended on December 14, only three homes remained standing in Linn City. No one died in the Linn City flood, but the destruction was too significant for the town to recover, and it was abandoned. Today the city of West Linn stands about where Linn City once was. Significant flooding recurred in the winter of early 1890. Portland's main street was completely submerged, communication over the Cascades was cut off, and many rail lines were forced to shut down. caused seven deaths in Portland and evacuations in Eugene in January 1943, flooded Corvallis in November 1946, contributed to the destruction of Vanport City and the death of about 15 of its residents in May 1948, and nearly flooded parts of Salem in December 1948. Although the Willamette was, by the mid 20th century, heavily engineered and controlled by a complex system of dams, channels, and barriers, it experienced severe floods through the end of the century. Storms caused a major flood that swelled the Willamette and other rivers in the Pacific Northwest from December 1964 through January 1965, submerging nearly of land. Before dawn on December 21, 1964, the Willamette reached 29.4 feet (9 m), which was higher than the seawall on its banks in Portland. By this time, about 15 people had died as a result of the flooding, and about 8,000 had been forced to evacuate their homes. On December 24, 1964, President Lyndon B. Johnson ordered federal aid for the flooded areas as the Willamette continued to rise. In the next couple of days, the river receded, but on December 27, it was at 29.8 feet (9 m), which was still nearly 12 feet (4 m) above the flood stage. The river continued to pose flood threats through January 1965, and more stormy weather occurred along the Pacific Coast. In February 1996, heavy warm rains driven by a subtropical jet stream fell on a deep 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. An Associated Press journalist reported, "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." but the inundated acreage was smaller than in 1964—only about In October, they were replaced by a larger steel wall that cost the city about $300,000. The new wall had removable steel plates designed to better prevent future flooding.

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. Domestic and industrial waste from the cities built up along the river "essentially [turned] the main stem river into an open sewer by the 1920s." 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. Despite earlier cleanup efforts, 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 mile (19 km) of the river, in Portland. As a result, this section of the river was designated a Superfund site in 2000, involving the U. S. Environmental Protection Agency (EPA) in cleanup of the river bottom. The area to be addressed stretches from the Fremont Bridge almost to the Columbia – spanning nearly 11 river miles. Reducing risk from the pollutants in this stretch will involve removing contaminated sediment from the river bottom and efforts to contain contaminated sediment by placing clean sediment on top (known as "capping"). Pollution has been exacerbated by combined sewer overflows, which the city has greatly reduced through its Big Pipe Project. Farther upstream, the pressing environmental issues have mainly been variations in pH and dissolved oxygen. The Willamette is nevertheless clean enough to be used by cities such as Corvallis and Wilsonville for drinking water. Since pollution concerns are primarily along the lower river, the Willamette 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). 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 down to the Hawthorne Bridge in Portland (RM 13, RK 21) at 85. Scores were in the "fair" category farther downstream; the least favorable reading was 81 at the Swan Island Channel midpoint (RM 0.5, RK 0.8). 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.

Over the past 150 years, a significant change for the Willamette River has been the loss of its floodplain forests, which covered an estimated 89 percent of a 400 feet (122 m) band along each river bank in 1850. The central valley—a former perennial grass prairie interspersed with oak, Douglas fir, ponderosa pine, 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 are predominantly Douglas fir, Pacific silver fir, western hemlock, and western red cedar. In the central valley, several projects have been done to restore and protect wetlands in order to provide habitat for bald eagles, Fender's blue butterfly, Oregon chub, Bradshaw's desert parsley, a variety of Willamette fleabane, and Kincaid's lupine. 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. Beaver populations, presumed to be much lower than historic levels, are increasing throughout the basin.

— "Oregon Water Quality Index Summary Report, Water Years 1998–2007" (PDF), 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. . Bright, William (2004). Native American Placenames of the United States. Norman, Oklahoma: University of Oklahoma Press. . Campbell, Lyle (1997). American Indian Languages. New York, New York: Oxford University Press. . 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. . Edwards, G. Thomas; Schwantes, Carlos A. (1986). Experiences in a Promised Land: Essays in Pacific Northwest History. Seattle: University of Washington Press. . Engeman, Richard H. (2009). The Oregon Companion: A Historical Gazetteer of the Useful, the Curious, and the Arcane. Portland, Oregon: Timber Press. . Gulick, Bill (2004). Steamboats on Northwest Rivers. Caldwell, Idaho: Caxton Press. . Holman, Frederick Van Voorhies (1907). Dr. John McLoughlin, the Father of Oregon. Cleveland, Ohio: A. H. Clark Company. . Laenen, Antonius; Dunnette, David A. (1997). River Quality: Dynamics and Restoration. Boca Raton, Florida: CRC Press. . 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. . Mackie, Richard Somerset (1997). Trading Beyond the Mountains: the British Fur Trade on the Pacific, 1793–1843. Vancouver: UBC Press. . McArthur, Lewis A.; McArthur, Lewis L. (2003) [1928]. Oregon Geographic Names (7th ed.). Portland, Oregon: Oregon Historical Society Press. . Orr, Elizabeth L.; Orr, William N. (1999). Geology of Oregon (5th ed.). Dubuque, Iowa: Kendall/Hunt Publishing Company. . Orr, Elizabeth L.; Orr, William N. (2012). Oregon Geology (6th ed.). Corvallis, Oregon: Oregon State University Press. . Samson, Karl (2010). Frommer's Oregon. Hoboken, New Jersey: Wiley Blackwell. . Smith, Dwight A.; Norman, James B.; Dykman, Pieter T. (1989) [1986]. Historic Highway Bridges of Oregon (2nd ed.). Portland, Oregon: Oregon Historical Society Press. . Snipp, C. Matthew (1989). American Indians: The First of This Land. New York, New York: Russell Sage Foundation. . Stenzel, Franz (1972). Cleveland Rockwell: Scientist and Artist, 1837–1907. Portland, Oregon: Oregon Historical Society. . Wortman, Sharon Wood; Wortman, Ed. ; Norman, James B. (2006). The Portland Bridge Book (3rd ed.). Portland, Oregon: Urban Adventure Press. .