The Columbia River (known as Wimahl or Big River to the Chinook-speaking natives who live on its lowermost reaches) is the largest river in the Pacific Northwest region of North America. It is named after the Columbia Rediviva, the first ship from the western world known to have traveled up the river. It stretches from the Canadian province of British Columbia (BC) through the U.S. state of Washington, forming much of the border between Washington and Oregon before emptying into the Pacific Ocean. The river is long, and its drainage basin is .
Measured by the volume of its flow, the Columbia is the largest river flowing into the Pacific from North America and is the fourth-largest river in the U.S. The river's heavy flow, and its large elevation drop over a relatively short distance, give it tremendous potential for the generation of electricity. It is the largest hydroelectric power producing river in North America with fourteen hydroelectric dams in the U.S. and Canada, and many more on various tributaries.
The Columbia and its tributaries are home to numerous anadromous fish, which migrate between fresh water streams and the Pacific Ocean. These fish—especially the various species of salmon—have been a vital part of the river's ecology and the local economy for thousands of years.
The development of the river for human use, and the industrial waste that resulted in some cases, have come into conflict with ecological conservation numerous times since Americans and Europeans began to settle the area in the 18th century. The taming, or harnessing—two terms commonly used in the early 20th century to describe the development of the rivers of the American west—included dredging for navigation by larger ships, nuclear power generation and nuclear weapons research and production, and the construction of dams for power generation, irrigation, navigation, and flood control.
The Columbia shares its name with nearby places, such as British Columbia, as well as with landforms and bodies of water. Columbia Lake, above sea level, and the adjoining Columbia Wetlands form the river's headwaters in the southern Rocky Mountain Trench. The trench is a broad, deep, and long glacial valley between the Canadian Rockies and the Columbia Mountains in British Columbia. For its first , the Columbia flows northwest along the trench through Windermere Lake and the town of Invermere, a region known in BC as the Columbia Valley, then northwest to Golden and into Kinbasket Lake. Rounding the northern end of the Selkirk Mountains, the river turns sharply south through a region known as the Big Bend Country, passing through Revelstoke Lake and the Arrow Lakes. Revelstoke, the Big Bend, and 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, and Trail, two major centres of the West Kootenay region. The Pend Oreille River joins the Columbia about north of the U.S.–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 Okanagan River confluence, then southeasterly near the confluence with the Wenatchee River in central Washington. This C-shaped segment of the river is also 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, and the Grand Coulee was left dry. The construction of the Grand Coulee Dam in the mid-20th century backed the river up, 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, and then past the Hanford Nuclear Reservation. Hanford Reach, a section of the Columbia between Priest Rapids Dam and the Tri-Cities, is the only U.S. stretch of the river that is completely free-flowing, unimpeded by dams, and not a tidal estuary. The Snake River and Yakima River join the Columbia in the Tri-Cities area. The Columbia makes a sharp bend to the west at the Washington–Oregon border. The river defines that border for the final of its journey.
The Deschutes River joins the Columbia near The Dalles. Between The Dalles and Portland, the river cuts through the Cascade Mountains, forming the dramatic Columbia River Gorge. Along with the Klamath River in southern Oregon and the Pit River in northern California, the Columbia is one of only three rivers to pass through the Cascades. The gorge is known for its strong and steady winds, scenic beauty, and its role as an important transportation link.
The river continues west, bending sharply to the north-northwest near Portland and Vancouver, Washington, at the Willamette River confluence. Here the river slows considerably, dropping sediment that might otherwise form a river delta. Near Longview, Washington and the Cowlitz River confluence, the river turns west again. The Columbia empties into the Pacific Ocean just west of Astoria, Oregon, over the Columbia Bar, a shifting sandbar that makes the river's mouth one of the most hazardous stretches of water to navigate in the world.
Twenty to forty million years ago, in the Eocene and Miocene eras, tremendous volcanic eruptions formed much of the landscape traversed by the Columbia. The Columbia River Plateau was covered by flood basalt lava, which forced the Columbia River into its present course. The Cascade Range began to uplift during the Pleistocene era (the last ice age, two million to 700,000 years ago). Cutting through the uplifting mountains, the Columbia River created the Columbia River Gorge.
The river and its drainage basin experienced some of the world’s greatest known catastrophic floods toward the end of the last ice age. The periodic rupturing of ice dams at Glacial Lake Missoula resulted in the Missoula Floods, with discharge rates ten times the combined flow of all the rivers of the world, as many as forty times over a thousand-year period.
The floodwaters rushed across eastern Washington, creating the channeled scablands, which are a complex network of dry canyon-like channels, or coulees that are often braided and sharply gouged into the basalt rock underlying the region's deep topsoil. Numerous flat-topped buttes with rich soil stand high above the chaotic scablands. Constrictions at several places caused the floodwaters to pool into large temporary lakes, such as Lake Lewis, in which sediments were deposited. Water depths have been estimated at at Wallula Gap, at Bonneville Dam, and over modern Portland, Oregon. Sediments were also deposited when the floodwaters slowed in the broad flats of the Quincy, Othello, and Pasco Basins. The floods' periodic inundation of the lower Columbia River Plateau deposited rich sediments, establishing the fertility that supports extensive agriculture in the modern era.
The river was blocked by the collapse of a mountain on the north side of the Columbia River Gorge, likely a result of the Cascadia earthquake in 1700, in an event known as the Bonneville Slide. The resulting land bridge blocked the river until rising waters tunneled through and finally washed away the sediment. It is not known how long it took the river to break through the barrier although estimates range from several months to several years. The landslide debris is still present in the form of the Cascade Rapids. In 1980, the eruption of Mount St. Helens deposited large amounts of sediment in the lower Columbia, temporarily reducing the depth of the shipping channel by .
Humans have inhabited the Columbia River Basin for more than 15,000 years, with a transition to a sedentary lifestyle based mainly on salmon starting about 3,500 years ago. In 1962, archaeologists found evidence of human activity dating back 11,230 years at the Marmes Rockshelter, near the confluence of the Palouse and Snake rivers in eastern Washington. In 1996, the skeletal remains of a 9,000-year-old prehistoric man (dubbed Kennewick Man) were found near Kennewick, Washington. The discovery rekindled debate in the scientific community over the origins of human habitation in North America and sparked a protracted controversy over whether the scientific or Native American community was entitled to possess and/or study the remains.
Many different Native Americans and First Nations tribes have a historical and continuing presence on the Columbia. The Sinixt or Lakes people lived on the lower stretch of the Canadian portion (also claimed as part of Okanagan territory) the Secwepemc, Ktunaxa and at one time the Blackfoot on the upper; the Colville, Spokane, Yakama, Nez Perce, Umatilla, and the Confederated Tribes of Warm Springs live along the U.S. stretch. Along the upper Snake River and Salmon River, the Shoshone Bannock tribes are present. The Cowlitz and Chinook tribes, which are not federally recognized, also live near the lower Columbia River. The Yakama, Nez Perce, Umatilla, and Warm Springs tribes all have treaty fishing rights along the Columbia and its tributaries.
Somewhere between 1450 and 1760, the Bonneville Slide created a land bridge in the Columbia Gorge, known to natives as the Bridge of the Gods. The bridge was described as the result a battle between gods, represented by Mount Adams and Mount Hood, vying for the affection of a goddess, represented by Mount St. Helens. The bridge permitted increased interaction and trade between tribes on the north and south sides of the river until it was finally washed away.
The Cascades Rapids of the Columbia River Gorge, and Kettle Falls and Priest Rapids in eastern Washington, were important fishing and trading sites submerged by the construction of dams. The Confederated Tribes of Warm Springs, a coalition of various tribes, adopted a constitution and incorporated after the 1938 completion of the Bonneville Dam flooded Cascades Rapids.
For 11,000 years, Celilo Falls was the most significant economic and cultural hub for native peoples on the Columbia. It was located east of the modern city of The Dalles. An estimated 15 to 20 million salmon passed through the falls every year, making it one of the most productive fishing sites in North America. The annual catch by natives in prehistoric times has been estimated at 42 million pounds. The falls were located at the border between Chinookan and Sahaptian speaking peoples and served as the center of an extensive trading network across the Pacific Plateau. Salmon canneries established by white settlers beginning in 1867 had a strong negative impact on the salmon population, and in 1908 President Theodore Roosevelt observed that the salmon runs were but a fraction of what they had been 25 prior.
Celilo was the oldest continuously inhabited community on the North American continent until 1957, when it was submerged by the construction of The Dalles Dam and the native fishing community was displaced. The affected tribes received a $26.8 million settlement for the loss of Celilo and other fishing sites submerged by The Dalles Dam. The Confederated Tribes of Warm Springs used part of its $4 million settlement to establish the Kah-Nee-Tah resort south of Mount Hood.
Another important area of indigenous cultural contact developed more recently than Celilo Falls. Horses spread through the Great Plains and helped create the horse, or plains culture, which diffused into the Columbia River's watershed via the Shoshone peoples of the upper Snake River in the late 18th century. The Nez Perce and Cayuse acquired horses around 1800. The Nez Perce and others made seasonal long-distance trips to the east for bison hunting, strengthening the cultural link with the plains culture. Other peoples such as the Yakama, Umatilla, and Palus also adopted aspects of the plains culture. The cultural transformation brought about by horses included long-distance travel, larger and more powerful tribal confederacies, and a linking of wealth and prestige to horses, bison hunting, and warfare.
Some historians believe that Japanese or Chinese vessels blown off course reached the Northwest Coast long before Europeans, possibly as early as 219 B.C. It is unknown whether they landed near the Columbia. Evidence exists that Spanish castaways reached the shore in 1679 and traded with the Clatsop; if these were indeed the first Europeans to see the Columbia, they failed to send word home to Spain.
The first documented European discovery of the Columbia River was that of Bruno de Heceta, who in 1775 sighted the river's mouth. On the advice of his officers, he did not explore it, as he was short-staffed and the current was strong. He considered it a bay, and called it Ensenada de Asunción. Later Spanish maps based on his discovery showed a river, labeled Rio de San Roque, or an entrance, called Entrada de Hezeta.
Following Heceta's reports, British fur trader Captain John Meares searched for the river in 1788, but he misread the currents and concluded that the river did not exist. He named Cape Disappointment for the non-existent river, not realizing the cape marks the northern edge of the river's mouth. Royal Navy commander George Vancouver sailed past the mouth in April 1792 and observed a change in the water's color, but he accepted Meares' report and continued on his journey northward. Later that month, Vancouver encountered the American captain Robert Gray at the Strait of Juan de Fuca. Gray reported that he had seen the entrance to the Columbia and planned to sail into it.
On May 12, 1792, Gray returned south and crossed the Columbia Bar, becoming the first explorer to enter the river. Gray's fur trading mission had been financed by Boston merchants, who outfitted him with a private vessel named Columbia Rediviva; he named the river after the ship on May 18. Gray spent nine days trading near the mouth of the Columbia, then left without having gone beyond upstream. Gray's discovery of the Columbia was later used by the United States to support their claim to the Oregon Country, which was also claimed by Russia, Great Britain, Spain and other nations.
In October 1792, Vancouver sent Lieutenant William Robert Broughton, his second-in-command, up the river. Broughton got as far as the Sandy River at the western end of the Columbia River Gorge, about upstream, sighting and naming Mount Hood. Broughton formally claimed the river, its drainage basin, and the nearby coast for Britain. In contrast, Gray had not made any formal claims on behalf of the United States.
People had long speculated about the existence of a Northwest Passage (or a great western river) connecting Pacific Ocean to the Atlantic (or to inland North America), and some mapmakers depicted it on their maps. As the Columbia was at the same latitude as the headwaters of the Missouri River, some people now concluded that Gray and Vancouver had discovered the Northwest Passage. A 1798 British map showed a dotted line connecting the Columbia with the Missouri. However, when the American explorers Meriwether Lewis and William Clark charted the vast, unmapped lands of the American West in their overland expedition (1803–05), they found no passage between the rivers. After crossing the Rocky Mountains, Lewis and Clark built dugout canoes and paddled down the Snake River, reaching the Columbia near the present-day Tri-Cities, Washington. They explored a few miles upriver, as far as Bateman Island, before heading down the Columbia, concluding their journey at the river's mouth and establishing Fort Clatsop, a short-lived establishment that was occupied for less than three months.
Canadian explorer David Thompson, of the North West Company, spent the winter of 1807–08 at Kootenae House near the source of the Columbia at present-day Invermere, British Columbia. Over the next few years he explored much of the river and its northern tributaries. In 1811, he traveled down the Columbia to the Pacific Ocean, arriving at the mouth just after John Jacob Astor's Pacific Fur Company had founded Astoria. On his return to the north Thompson explored the one remaining part of the river he had not yet seen, becoming the first European-American to travel the entire length of the river.
In 1825 the Hudson's Bay Company (HBC) established Fort Vancouver on the the bank of the Columbia, in what is now Vancouver, Washington, as the headquarters of the company's Columbia District, which encompassed everything west of the Rocky Mountains. Dr. John McLoughlin was appointed Chief Factor of the Columbia District. The HBC reoriented its Columbia District operations toward the Pacific Ocean via the Columbia, which became the region's main trunk route. In the early 1840s Americans began to colonize the Oregon in large numbers via the Oregon Trail, in spite of the HBC's efforts to discourage American settlement of the region. For many the final leg of the journey involved travel down the lower Columbia River to Fort Vancouver. The final leg of the Oregon Trail, from The Dalles to Fort Vancouver, was the trail's most treacherous stretch, which prompted the 1846 construction of the Barlow Road.
In the Treaty of 1818 the United States and Britain agreed that both nations were to enjoy equal rights in Oregon Country for 10 years. By 1828, when the so-called "joint occupation" was renewed for an indefinite period, it seemed probable that the lower Columbia River would in time become the border. For years the Hudson's Bay Company successfully maintained control of the Columbia River and American attempts to gain a foothold were fended off. In the 1830s, however, American religious missions were established at several locations in the lower Columbia River region. And in the 1840s a mass migration of American settlers undermined British control. The Hudson's Bay Company tried maintain dominance by shifting from the fur trade, which was in sharp decline, to exporting other goods such as salmon and lumber. Colonization schemes were attempted, but failed to match the scale of American settlement. Americans generally settled south of the Columbia, mainly in the Willamette Valley. The Hudson's Bay Company tried to establish settlements north of the river, but nearly all the British colonists moved south to the Willamette Valley. The hope that the British colonists might dilute the American flavor of the valley failed in the face of the overwhelming number of American settlers. These developments rekindled the issue of "joint occupation" and the boundary dispute . While some British interests, especially the Hudson's Bay Company, fought for a boundary along the Columbia River, the Oregon Treaty of 1846 set the boundary at the 49th parellel. The Columbia River did become the border between the U.S. territories of Oregon and Washington. Oregon became a U.S. state in 1859, Washington in 1889.
By the turn of the 20th century, the difficulty of navigating the Columbia was seen as an impediment to the economic development of the Inland Empire region east of the Cascades. The dredging and dam building that followed would permanently alter the river, disrupting its natural flow but also providing electricity, irrigation, navigability and other benefits to the region.
American captain Robert Gray and British captain George Vancouver, who explored the river in 1792, proved that it was possible to cross the Columbia Bar. Many of the challenges associated with that feat remain today; even with modern engineering alterations to the mouth of the river, the strong currents and shifting sandbar make it dangerous to pass between the river and the Pacific Ocean.
The use of steamboats along the river, beginning with the British Beaver in 1836 followed by American vessels in 1850, contributed to the rapid settlement and economic development of the region. Steamboats operated in several places: on the river's lower reaches, from the Pacific Ocean to Cascades Rapids, from the Cascades to Celilo Falls, and from Celilo to the confluence with the Snake River; on the Wenatchee Reach of eastern Washington; on British Columbia's Arrow Lakes; and on tributaries like the Willamette, the Snake and Kootenay Lake. The boats, initially powered by burning wood, carried passengers and freight throughout the region for many years. Railroads served to connect steamboat lines interrupted by waterfalls on the river's lower reaches. In the 1880s, railroads maintained by companies such as the Oregon Railroad and Navigation Company and the Shaver Transportation Company began to supplement steamboat operations as the major transportation links along the river.
The shifting Columbia Bar makes passage between the river and the Pacific Ocean difficult and dangerous, and numerous rapids along the river hinder navigation. Jetties, first constructed in 1886, extend the river's channel into the ocean. Strong currents and the shifting sandbar remain a threat to ships entering the river and necessitate continuous maintenance of the jetties.
In 1891 the Columbia was dredged to enhance shipping. The channel between the ocean and Portland and Vancouver was deepened from to The Columbian newspaper called for the channel to be deepened to as early as 1905, but that depth was not attained until 1976.
Navigation locks were first constructed in 1896 around the Cascades Rapids, enabling boats to travel safely through the Columbia River Gorge. The Celilo Canal, bypassing Celilo Falls, opened to river traffic in 1915. In the mid-20th century, the construction of dams along the length of the river submerged the rapids beneath a series of reservoirs. An extensive system of locks allowed ships and barges to pass easily from one reservoir to the next. A navigation channel reaching to Lewiston, Idaho, along the Columbia and Snake Rivers, was completed in 1975. One of the main commodities is wheat, mainly for export. More than 40 percent of all US wheat exports are barged on the Columbia River.
The 1980 eruption of Mount St. Helens caused mudslides in the area, which reduced the Columbia's depth by for a stretch, disrupting Portland's economy.
In 1999, Congress authorized deepening the channel between Portland and Astoria from to , which will make it possible for large container and grain ships to reach Portland and Vancouver. The project includes measures to mitigate environmental damage; for instance, for every acre (4,000 m²) of wetland damaged by the project, the U.S. Army Corps of Engineers must restore of wetland. However, it has met opposition due to concerns about stirring up toxic sediment on the riverbed. Portland-based Northwest Environmental Advocates brought a lawsuit against the Army Corps of Engineers, but it was rejected by the Ninth U.S. Circuit Court of Appeals in August 2006. In early 2006, the Corps spilled of hydraulic oil into the Columbia, drawing further criticism from environmental organizations.
Work on the project began in 2005 and is expected to conclude in 2010. The project's cost is estimated at $150 million. The federal government is paying 65 percent, Oregon and Washington are paying $27 million each, and six local ports are also contributing to the cost.
In 1902, the United States Bureau of Reclamation was established to aid in the economic development of arid western states. One of its major undertakings was building Grand Coulee Dam to provide irrigation for the of the Columbia Basin Project in central Washington. With the onset of World War II, the focus of dam construction shifted to production of hydroelectricity. Irrigation efforts resumed after the war.
River development occurred within the structure of the 1909 International Boundary Waters Treaty between the U.S. and Canada. The United States Congress passed the Rivers and Harbors Act of 1925, which directed the Army Corps of Engineers and the Federal Power Commission to explore the development of the nation's rivers. This prompted agencies to conduct the first formal financial analysis of hydroelectric development; the reports produced by various agencies were presented in House Document 308. Those reports, and subsequent related reports, are referred to as 308 Reports.
In the late 1920s, political forces in the Northwestern United States generally favored private development of hydroelectric dams along the Columbia. But the overwhelming victories of gubernatorial candidate George W. Joseph in the 1930 Oregon Republican Party primary, and later his law partner Julius Meier, were understood to demonstrate strong public support for public ownership of dams. In 1933, President Franklin D. Roosevelt signed a bill that enabled the construction of the Bonneville and Grand Coulee dams as public works projects. The legislation was attributed to the efforts of Oregon Senator Charles McNary, Washington Senator Clarence Dill, and Oregon Congressman Charles Martin, among others.
In 1948 floods swept through the Columbia watershed, destroying Vanport, then the second largest city in Oregon, and impacting cities as far north as Trail, British Columbia. The flooding prompted the United States Congress to pass the Flood Control Act of 1950, authorizing the federal development of additional dams and other flood control mechanisms. By that time, however, local communities had become wary of federal hydroelectric projects, and sought local control of new developments; a Public Utility District in Grant County, Washington ultimately began construction of the dam at Priest Rapids.
In the 1960s, the United States and Canada signed the Columbia River Treaty, which focused on flood control and the maximization of downstream power generation. Canada agreed to build dams and provide reservoir storage, and the U.S. agreed to deliver to Canada one-half of the increase in U.S. downstream power benefits as estimated five years in advance. Canada's obligation was met by building three dams (two on the Columbia, and one on the Duncan River), the last of which was completed in 1973.
Today the main stem of the Columbia River has 14 dams, of which three are in Canada and 11 in the U.S. Four mainstem dams and four lower Snake River dams contain navigation locks to allow ship and barge passage from the ocean as far as Lewiston, Idaho. The river system as a whole has more than 400 dams for hydroelectricity and irrigation. The dams address a variety of demands, including flood control, navigation, stream flow regulation, storage and delivery of stored waters, reclamation of public lands and Indian reservations, and the generation of hydroelectric power.
The larger U.S. dams are owned and operated by the federal government (some by the Army Corps of Engineers and some by the Bureau of Reclamation), while the smaller dams are operated by public utility districts, and private power companies. The federally operated system is known as the Federal Columbia River Power System, which includes 31 dams on the Columbia and its tributaries. The system has altered the seasonal flow of the river in order to meet higher electricity demands during the winter. At the beginning of the 20th century, roughly 75 percent of the Columbia's flow occurred in the summer, between April and September. By 1980, the summer proportion had been lowered to about 50 percent, essentially eliminating the seasonal pattern.
The installation of dams dramatically altered the landscape and ecosystem of the river. At one time, the Columbia was one of the top salmon-producing river systems in the world. Previously active fishing sites, most notably Celilo Falls in the eastern Columbia River Gorge, have exhibited a sharp decline in fishing along the Columbia in the last century, and salmon populations have been dramatically reduced. Fish ladders have been installed at some dam sites to help the fish journey to spawning waters. Chief Joseph Dam has no fish ladders and completely blocks fish migration to the upper half of the Columbia River system.
The project's initial purpose was irrigation, but the onset of World War II created a high demand for electricity, mainly for aluminum production and for the development of nuclear weapons at the Hanford Site. Irrigation began in 1951. The project provides water to more than of fertile but arid lands in central Washington State. Water from the project has transformed the region from a wasteland barely able to produce subsistence levels of dry-land wheat crops to a major agricultural center. Important crops include apples, potatoes, alfalfa, wheat, corn (maize), barley, hops, beans, and sugar beets.
Since 1750, the Columbia has experienced six multi-year droughts. The longest, lasting 12 years in the mid-1800s, reduced the river's flow to 20 percent below average. Scientists have expressed concern that a similar drought would have grave consequences in a region so dependent on the Columbia. In 1992–93, a lesser drought affected farmers, hydroelectric power producers, shippers, and wildlife managers.
Many farmers in central Washington build dams on their property for irrigation and to control frost on their crops. The Washington Department of Ecology, using new techniques involving aerial photographs, estimated there may be as many as 100 such dams in the area, most of which are illegal. Six such dams have failed in recent years, causing hundreds of thousands of dollars of damage to crops and public roads. Fourteen farms in the area have gone through the permitting process to build such dams legally.
The Columbia's heavy flow and extreme elevation drop over a short distance, , give it tremendous capacity for hydroelectricity generation. In comparison, the Mississippi drops less than . The Columbia alone possesses a third of the United States's hydroelectric potential.
Inexpensive hydro-power supported the emergence of an extensive aluminum industry, which draws tremendous amounts of power. Until 2000, the Northwestern United States produced up to 17 percent of the world's aluminum and 40 percent of the aluminum produced in the U.S. But the commoditization of power in the early 2000s, coupled with drought that reduced the generation capacity of the river, damaged the industry. By 2001, Columbia River aluminum producers had idled 80 percent of its production capacity, and by 2003, the entire U.S. produced only 15 percent of the world's aluminum, many smelters among the Columbia having gone dormant or out of business.
Power remains relatively inexpensive along the Columbia, and in recent years high-tech companies like Google have begun to move server farm operations into the area to avail themselves of cheap power.
Downriver of Grand Coulee, each dam’s reservoir is closely regulated by the Bonneville Power Administration (BPA), Army Corps of Engineers, and various Washington Public Utility Districts to ensure flow, flood control, and power generation objectives are met. Increasingly, hydro-power operations are required to meet standards under the U.S. Endangered Species Act and other agreements to manage operations to minimize impacts on salmon and other fish, and some conservation and fishing groups support removing four dams on the lower Snake River, the largest tributary of the Columbia.
In 1941, the BPA hired Oklahoma folksinger Woody Guthrie to write songs for a documentary film promoting the benefits of hydropower. In the month he spent traveling the region Guthrie wrote 26 songs, which have become an important part of the cultural history of the region.
The Columbia supports several species of anadromous fish that migrate between the Pacific Ocean and fresh water tributaries of the river. Coho and Chinook (also known as "king") salmon, and steelhead, all of the genus Oncorhynchus, are ocean fish that migrate up the rivers at the end of their life cycles to spawn. White sturgeon, which take 25 years to grow to full size, typically migrate between the ocean and the upstream habitat several times during their lives.
Dams interrupt the migration of anadromous fish. Salmon and steelhead return to the streams in which they were born to spawn; where dams prevent their return, entire populations of salmon die. Some of the Columbia and Snake River dams employ fish ladders, which are effective to varying degrees at allowing these fish to travel upstream. Another problem exists for the juvenile salmon headed downstream to the ocean. Previously, this journey would have taken two to three weeks. With river currents slowed by the dams, and the Columbia converted from wild river to a series of slackwater pools, the journey can take several months, which increases the mortality rate. In some cases, the Army Corps of Engineers transports juvenile fish downstream by truck or river barge. The Chief Joseph Dam and several dams on the Columbia's tributaries entirely block migration, and there are no migrating fish on the river above these dams. Sturgeon have different migration habits and can survive without ever visiting the ocean. In many upstream areas cut off from the ocean by dams, sturgeon simply live upstream of the dam.
In 1994, the salmon catch was smaller than usual in the rivers of Oregon, Washington, and British Columbia, causing concern among commercial fishermen, government agencies, and tribal leaders. U.S. government intervention, to which the states of Alaska, Idaho, and Oregon objected, included an 11-day closure of an Alaska fishery. In April 1994 the Pacific Fisheries Management Council unanimously approved the strictest regulations in 18 years, banning all commercial salmon fishing for that year from Cape Falcon north to the Canadian border. In the winter of 1994, the return of coho salmon far exceeded expectations, which was attributed in part to the fishing ban.
Also in 1994, United States Secretary of the Interior Bruce Babbitt first proposed the removal of several Pacific Northwest dams because of their impact on salmon spawning. The Northwest Power Planning Council approved a plan that provided more water for fish and less for electricity, irrigation, and transportation. Environmental advocates have called for the removal of certain dams in the Columbia system in the years since. Of the 227 major dams in the Columbia River drainage basin, the four Washington dams on the lower Snake River are often identified for removal, notably in an ongoing lawsuit concerning a Bush administration plan for salmon recovery. These dams and reservoirs currently limit the recovery of upriver salmon runs to Idaho's Salmon and Clearwater rivers. Historically, the Snake produced over 1.5 million spring and summer Chinook Salmon, a number that has dwindled to several thousand in recent years. Idaho Power Company's Hells Canyon dams have no fish ladders (and do not pass juvenile salmon downstream), and thus allow no steelhead or salmon to migrate above Hells Canyon. In 2007, the destruction of the Marmot Dam on the Sandy River was the first dam removal in the system. There are plans to remove the Condit Dam on Washington's White Salmon River, and the Milltown Dam on the Clark Fork in Montana.
The nuclear reactors were decommissioned at the end of the Cold War, and the Hanford site is now the focus of the world’s largest environmental cleanup, managed by the Department of Energy under the oversight of the Washington Department of Ecology and the Environmental Protection Agency. Nearby aquifers contain an estimated 270 billion US gallons (1 billion m³) of groundwater contaminated by high-level nuclear waste that has leaked out of Hanford's massive underground storage tanks. As of 2008, 1 million US gallons (3,785 m³) of highly radioactive waste is traveling through groundwater toward the Columbia River. This waste is expected to reach the river in 12 to 50 years if cleanup does not proceed on schedule.
In addition to concerns about nuclear waste, numerous other pollutants are found in the river. These include chemical pesticides, bacteria, arsenic, dioxins, and polychlorinated biphenyl (PCB).
Studies have also found significant levels of toxins in fish and the waters they inhabit within the basin. Accumulation of toxins in fish threatens the survival of fish species, and human consumption of these fish can lead to health problems. Water quality is also an important factor in the survival of other wildlife and plants that grow in the Columbia River drainage basin. The states, Indian tribes, and federal government are all engaged in efforts to restore and improve the water, land, and air quality of the Columbia River drainage basin and have committed to work together to enhance and accomplish critical ecosystem restoration efforts. A number of cleanup efforts are currently underway, including Superfund projects at Portland Harbor, Hanford, and Lake Roosevelt.
Timber harvesting further contaminates river water; the Northwest Forest Plan, a piece of federal legislation from 1994, mandated that timber companies consider the environmental impacts of their practices on rivers like the Columbia.
On July 1, 2003, Christopher Swain of Portland, Oregon, became the first person to swim the Columbia River's entire length, in an effort to raise public awareness about the river's environmental health.
Most of the Columbia' drainage basin, which is about the size of France, lies roughly between the Rocky Mountains on the east and the Cascade Mountains on the west. In the United States and Canada the term watershed is often used to mean drainage basin. The term Columbia Basin is used to refer not only to the entire drainage basin but also to subsets of the river's full watershed, such as the relatively flat and unforested area in eastern Washington bounded by the Cascades, the Rocky Mountains, and the Blue Mountains. Within the watershed are diverse landforms including mountains, arid plateaus, river valleys, rolling uplands, and deep gorges. Grand Teton National Park lies in the watershed, as well as parts of Yellowstone National Park, Glacier National Park, Mount Rainier National Park, and North Cascades National Park. Canadian National Parks in the watershed include Kootenay National Park, Yoho National Park, Glacier National Park, and Mount Revelstoke National Park. Hells Canyon, the deepest gorge in North America, and the Columbia Gorge are in the watershed. Vegetation varies widely, ranging from Western hemlock and Western redcedar in the moist regions to sagebrush in the arid regions. The watershed provides habitat for 609 known fish and wildlife species, including the bull trout, Bald Eagle, gray wolf, grizzly bear, and Canada lynx.
The World Wide Fund for Nature (WWF) divides the waters of the Columbia and its tributaries into three freshwater ecoregions, naming them: Columbia Glaciated, Columbia Unglaciated, and Upper Snake. The Columbia Glaciated ecoregion, making up about a third of the total watershed, lies in the north and was covered with ice sheets during the Pleistocene. The ecoregion includes the mainstem Columbia north of the Snake River and tributaries such as the Yakima, Okanagan, Pend Oreille, Clark Fork, and Kootenay Rivers. The effects of glaciation include a number of large lakes and a relatively low diversity of freshwater fish. The Upper Snake ecoregion is defined as the Snake River watershed above Shoshone Falls, which totally blocks fish migration. This region has 14 species of fish, many of which are endemic. The Columbia Unglaciated ecoregion makes up the rest of the watershed. It includes the mainstem Columbia below the Snake River and tributaries such as the Salmon, John Day, Deschutes, and lower Snake Rivers. Of the three ecoregions it is the richest in terms of freshwater species diversity. There are 35 species of fish, of which four are endemic. There are also high levels of mollusk endemism.
In 2000, about six million people lived within the Columbia' drainage basin. Of this total about 2.4 million people lived in Oregon, 1.7 million in Washington, 1 million in Idaho, half a million in British Columbia, and 0.4 million in Montana. Population in the watershed has been rising for many decades and is projected to rise to about 10 million by 2030. The highest population densities are found west of the Cascade Mountains along the I-5 corridor, especially in the Portland-Vancouver urban area. High densities are also found around Spokane, Washington, and Boise, Idaho. Although much of the watershed is rural and sparsely populated, areas with recreational and scenic values are growing rapidly. The central Oregon county of Deschutes is the fastest-growing in the state. Populations have also been growing just east of the Cascades in central Washington around the city of Yakima and the Tri-Cities area. Projections for the coming decades assume growth throughout the watershed, including the interior. The Canadian part of the Okanagan subbasin is also growing rapidly.
Climate varies greatly from place to place within the watershed. Elevation ranges from sea level at the river mouth to more than in the mountains, and temperatures vary with elevation. The highest peak is Mount Rainier, at . High elevations have cold winters and short cool summers; interior regions are subject to great temperature variability and severe droughts. Over some of the watershed, especially west of the Cascade Mountains, precipitation maximums occur in winter, when Pacific storms come ashore. Atmospheric conditions block the flow of moisture in summer, which is generally dry except for occasional thunderstorms in the interior. In some of the eastern parts of the watershed, especially shurb-steppe regions with continental climate patterns, precipitation maximums occur in early summer. Annual precipitation varies from more than a year in the Cascades to less than in the interior. Much of the watershed gets less than a year.
Several major North American drainage basins and many minor ones share a common border with the Columbia River's drainage basin. To the east, in northern Wyoming and Montana, the Continental Divide separates the Columbia watershed from the Mississippi-Missouri watershed, which empties into the Gulf of Mexico. To the northeast, mostly along the southern border between British Columbia and Alberta, the Continental Divide separates the Columbia watershed from the Nelson-Lake Winnipeg-Saskatchewan watershed, which empties into Hudson Bay. The Mississippi and Nelson watersheds are separated by the Laurentian Divide, which meets the Continental Divide at Triple Divide Peak near the headwaters of the Columbia's Flathead River tributary. This point marks the meeting of North America's three main drainage patterns, to the Pacific, Atlantic, and Arctic Oceans.
Further north along the Continental Divide, a short portion of the combined Continental and Laurentian divides separate the Columbia watershed from the MacKenzie-Slave-Athabasca watershed, which empties into the Arctic Ocean. The Nelson and Mackenzie watersheds are separated by a divide between streams flowing to the Arctic Ocean and those of the Hudson Bay watershed. This divide meets the Continental Divide at Snow Dome, near the northernmost bend of the Columbia River.
To the southeast, in western Wyoming, another divide separates the Columbia watershed from the Colorado-Green watershed, which empties into the Gulf of California. The Columbia, Colorado, and Mississippi watersheds meet at Three Waters Mountain in the Wind River Range of To the south, in Oregon, Nevada, Utah, Idaho, and Wyoming, the Columbia watershed is divided from the Great Basin, whose several watersheds are endorheic, not emptying into any ocean but rather drying up or sinking into sumps. Great Basin watersheds that share a border with the Columbia watershed include Harney Basin, Humboldt River, and Great Salt Lake. To the north, mostly in British Columbia, the Columbia watershed borders the Fraser River watershed. To the west and southwest the Columbia watershed borders a number of smaller watersheds that drain to the Pacific Ocean, such as the Klamath River in Oregon and California and the Puget Sound Basin in Washington.
The Snake is by far the largest tributary. Its discharge is nearly equal (about 46.5 percent) to the Columbia's at the rivers' confluence. Compared to the Columbia above the confluence, the Snake is longer (113 percent), and its drainage basin is larger (104 percent). The Pend Oreille and its main tributaries, Clark Fork and Flathead River, are similar. Compared to the Columbia above the Pend Oreille confluence, the Pend Oreille-Clark-Flathead is nearly as long (about 86 percent), its basin about three-fourths as large (76 percent), and its discharge over a third (37 percent).
|cu ft/s||m³/s||sq. mi.||sq. km.|
|Kootenay River (Kootenai)||30,650||867|
|Pend Oreille River||27,820||788|