Columbia River
Overview
 
The Columbia River is the largest river
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

 in the Pacific Northwest
Pacific Northwest
The Pacific Northwest is a region in northwestern North America, bounded by the Pacific Ocean to the west and, loosely, by the Rocky Mountains on the east. Definitions of the region vary and there is no commonly agreed upon boundary, even among Pacific Northwesterners. A common concept of the...

 region of North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

. The river rises in the Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...

 of British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...

, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

, flows northwest and then south into the U.S. state
U.S. state
A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of Washington, then turns west to form most of the border between Washington and the state of Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...

 before emptying into the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

. The river is 1243 miles (2,000.4 km) long, and its largest tributary is the Snake River
Snake River
The Snake is a major river of the greater Pacific Northwest in the United States. At long, it is the largest tributary of the Columbia River, the largest North American river that empties into the Pacific Ocean...

. Its drainage basin
Drainage basin
A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...

 is roughly the size of France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 and extends into seven U.S.
Encyclopedia
The Columbia River is the largest river
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

 in the Pacific Northwest
Pacific Northwest
The Pacific Northwest is a region in northwestern North America, bounded by the Pacific Ocean to the west and, loosely, by the Rocky Mountains on the east. Definitions of the region vary and there is no commonly agreed upon boundary, even among Pacific Northwesterners. A common concept of the...

 region of North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

. The river rises in the Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...

 of British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...

, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

, flows northwest and then south into the U.S. state
U.S. state
A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of Washington, then turns west to form most of the border between Washington and the state of Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...

 before emptying into the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

. The river is 1243 miles (2,000.4 km) long, and its largest tributary is the Snake River
Snake River
The Snake is a major river of the greater Pacific Northwest in the United States. At long, it is the largest tributary of the Columbia River, the largest North American river that empties into the Pacific Ocean...

. Its drainage basin
Drainage basin
A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...

 is roughly the size of France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 and extends into seven U.S. states and a Canadian province.

By volume, the Columbia is the fourth-largest river in the U.S., and it has the greatest flow of any North American river draining into the Pacific. The river's heavy flow and its relatively steep gradient give it tremendous potential for the generation of electricity. The 14 hydroelectric dams
Hydroelectric dams on the Columbia River
Hydroelectric dams on the Columbia River and its tributaries in North America.- Mainstem Columbia dams :-Snake River:-Pend Oreille-Clark Fork–Flathead:-Kootenai River:-See also:...

 on the Columbia's main stem
Main Stem
"Main Stem" is 1942 instrumental by Duke Ellington and His Famous Orchestra. Although recorded in 1942, the single would not be released until 1944 where it was Duke Ellington's last of four number one's on the Harlem Hit Parade. "Main Stem" would also peak at number twenty on the pop chart"Main...

 and many more on its tributaries produce more hydroelectric power than those of any other North American river.

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 many cultural groups of the region. The river system hosts many species of anadromous fish, which migrate between freshwater
Freshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...

 habitats and the saline
Saline water
Saline water is a general term for water that contains a significant concentration of dissolved salts . The concentration is usually expressed in parts per million of salt....

 Pacific Ocean. These fish—especially the salmon
Salmon
Salmon is the common name for several species of fish in the family Salmonidae. Several other fish in the same family are called trout; the difference is often said to be that salmon migrate and trout are resident, but this distinction does not strictly hold true...

 species—provided the core subsistence for natives; in past centuries, traders from across western North America traveled to the Columbia to trade for fish.

In the late 18th century, a private American ship became the first non-indigenous vessel to enter the river; it was followed by a British explorer, who navigated past the Oregon Coast Range
Oregon Coast Range
The Oregon Coast Range, often called simply the Coast Range and sometimes the Pacific Coast Range, is a mountain range, in the Pacific Coast Ranges physiographic region, in the U.S. state of Oregon along the Pacific Ocean...

 into the Willamette Valley
Willamette Valley
The Willamette Valley is the most populated region in the state of Oregon of the United States. Located in the state's northwest, the region is surrounded by tall mountain ranges to the east, west and south and the valley's floor is broad, flat and fertile because of Ice Age conditions...

. In the following decades, fur trading
Fur trade
The fur trade is a worldwide industry dealing in the acquisition and sale of animal fur. Since the establishment of world market for in the early modern period furs of boreal, polar and cold temperate mammalian animals have been the most valued...

 companies used the Columbia as a key transportation route. Overland explorers entered the Willamette Valley through the scenic but treacherous Columbia River Gorge
Columbia River Gorge
The Columbia River Gorge is a canyon of the Columbia River in the Pacific Northwest of the United States. Up to deep, the canyon stretches for over as the river winds westward through the Cascade Range forming the boundary between the State of Washington to the north and Oregon to the south...

, and pioneers began to settle the valley in increasing numbers, following both routes to enter it. Steamships along the river linked communities and facilitated trade; the arrival of railroads in the late 19th century, many running along the river, supplemented these links.

Since the late 19th century, public
Public sector
The public sector, sometimes referred to as the state sector, is a part of the state that deals with either the production, delivery and allocation of goods and services by and for the government or its citizens, whether national, regional or local/municipal.Examples of public sector activity range...

 and private
Private sector
In economics, the private sector is that part of the economy, sometimes referred to as the citizen sector, which is run by private individuals or groups, usually as a means of enterprise for profit, and is not controlled by the state...

 sectors have heavily developed the river. The development, commonly referred to as taming or harnessing of the river, has been massive and multi-faceted. To aid ship and barge navigation, locks
Lock (water transport)
A lock is a device for raising and lowering boats between stretches of water of different levels on river and canal waterways. The distinguishing feature of a lock is a fixed chamber in which the water level can be varied; whereas in a caisson lock, a boat lift, or on a canal inclined plane, it is...

 have been built along the lower Columbia and its tributaries, and dredging has opened, maintained, and enlarged shipping channels
Channel (geography)
In physical geography, a channel is the physical confine of a river, slough or ocean strait consisting of a bed and banks.A channel is also the natural or human-made deeper course through a reef, sand bar, bay, or any shallow body of water...

. Since the early 20th century, dams have been built across the river for the purposes of power generation, navigation, irrigation
Irrigation
Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...

, and flood control. Today, a dam-impounded reservoir
Reservoir
A reservoir , artificial lake or dam is used to store water.Reservoirs may be created in river valleys by the construction of a dam or may be built by excavation in the ground or by conventional construction techniques such as brickwork or cast concrete.The term reservoir may also be used to...

 lies along nearly every U.S. mile of the once free-flowing river, and much of the Canadian stretch has been impounded as well. Production of nuclear power
Nuclear power
Nuclear power is the use of sustained nuclear fission to generate heat and electricity. Nuclear power plants provide about 6% of the world's energy and 13–14% of the world's electricity, with the U.S., France, and Japan together accounting for about 50% of nuclear generated electricity...

 has taken place at two sites along the river. Plutonium for nuclear weapon
Nuclear weapon
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission bomb test released the same amount...

s was produced for decades at the Hanford Site
Hanford Site
The Hanford Site is a mostly decommissioned nuclear production complex on the Columbia River in the U.S. state of Washington, operated by the United States federal government. The site has been known by many names, including Hanford Works, Hanford Engineer Works or HEW, Hanford Nuclear Reservation...

, which is now the most contaminated nuclear site in the U.S. All these developments have had a tremendous impact on river environments, perhaps most notably through industrial pollution and barriers to fish migration.

Course

The Columbia begins its 1243 miles (2,000.4 km) journey in the southern Rocky Mountain Trench
Rocky Mountain Trench
The Rocky Mountain Trench, or the Trench or The Valley of a Thousand Peaks, is a large valley in the northern part of the Rocky Mountains. It is both visually and cartographically a striking physiographic feature extending approximately from Flathead Lake, Montana, to the Liard River, just south...

 in British Columbia (BC). Columbia Lake
Columbia Lake
Columbia Lake is the primary lake at the headwaters of the Columbia River, in British Columbia, Canada. It is fed by several small tributaries. The village of Canal Flats is located at the south end of the lake....

 – 2690 feet (819.9 m) above sea level
Sea level
Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...

 – and the adjoining Columbia Wetlands
Columbia Wetlands
The Columbia Wetlands is a 15,070 hectare wetland in the Columbia Valley region of southeastern British Columbia, Canada. It was designated a wetland of international importance on World Environment Day, June 5, 2005, and is the thirty-seventh such site in Canada. The wetland satisfies all the...

 form the river's headwaters. The trench is a broad, deep, and long glacial valley between the Canadian Rockies
Canadian Rockies
The Canadian Rockies comprise the Canadian segment of the North American Rocky Mountains range. They are the eastern part of the Canadian Cordillera, extending from the Interior Plains of Alberta to the Rocky Mountain Trench of British Columbia. The southern end borders Idaho and Montana of the USA...

 and the Columbia Mountains
Columbia Mountains
The Columbia Mountains are a group of mountain ranges located in southeastern British Columbia, and partially in Montana, Idaho and Washington. The mountain range covers 135,952 km² . The range is bounded by the Rocky Mountain Trench on the east, and the Kootenay River on the south; their...

 in BC. For its first 200 miles (321.9 km), the Columbia flows northwest along the trench through Windermere Lake
Windermere Lake (British Columbia)
Lake Windermere is a very large widening in the Columbia River. The village of Windermere is located on the east side of the lake, and the larger town of Invermere is located on the lake's northwestern corner...

 and the town of Invermere
Invermere, British Columbia
Invermere is a community in eastern British Columbia, Canada, near the border of Alberta. With its growing permanent population of almost 4,000 , swelling to near 40,000 on summer weekends, it is the hub of the Columbia Valley between Golden, and Cranbrook...

, a region known in BC as the Columbia Valley
Columbia Valley
The Columbia Valley is the name used for a region in the Rocky Mountain Trench near the headwaters of the Columbia River between the town of Golden and the Canal Flats. The main hub of the valley is the town of Invermere. Other towns include Radium Hot Springs, Windermere and Fairmont Hot Springs...

, then northwest to Golden
Golden, British Columbia
Golden is a town in southeastern British Columbia, Canada, located west of Calgary, Alberta and east of Vancouver.-History:Much of the town's history is tied into the Canadian Pacific Railway and the logging industry...

 and into Kinbasket Lake
Kinbasket Lake
Kinbasket Lake is a reservoir on the Columbia River in southeast British Columbia, north of the city of Revelstoke and the town of Golden. The reservoir was created by the construction of the Mica Dam. The lake includes two reaches, Columbia Reach and Canoe Reach , referring to the river valleys...

. Rounding the northern end of the Selkirk Mountains
Selkirk Mountains
The Selkirk Mountains are a mountain range spanning the northern portion of the Idaho Panhandle, eastern Washington, and southeastern British Columbia. They begin at Mica Peak near Coeur d'Alene, Idaho and extend approximately 320 km north from the border. The range is bounded on its west,...

, the river turns sharply south through a region known as the Big Bend Country
Big Bend Country
Big Bend Country is a term used in the Canadian province of British Columbia to refer to the region around the northernmost bend of the Columbia River, where the river leaves its initial northwestward course along the Rocky Mountain Trench to curve around the northern end of the Selkirk Mountains...

, passing through Revelstoke Lake
Revelstoke Lake
Lake Revelstoke or Revelstoke Lake or Revelstoke Lake Reservoir is an artificial lake on the Columbia River, north of the town of Revelstoke, British Columbia and south of Mica Creek...

 and the Arrow Lakes
Arrow Lakes
The Arrow Lakes in British Columbia, Canada, divided into Upper Arrow Lake and Lower Arrow Lake, are widenings of the Columbia River. The lakes are situated between the Selkirk Mountains to the east and the Monashee Mountains to the west. Beachland is fairly rare, and is interspersed with rocky...

. Revelstoke, the Big Bend, and the Columbia Valley combined are referred to in BC parlance as the Columbia Country
Columbia Country
The Columbia Country is a term used in the Canadian province of British Columbia to refer to the upper basin of the Columbia River in that province. It includes a smaller region known as the Columbia Valley, near the river's headwaters at Columbia Lake in the Rocky Mountain Trench, and the Big...

. Below the Arrow Lakes, the Columbia passes the cities of Castlegar
Castlegar, British Columbia
Castlegar is the second largest city in the West Kootenay region of British Columbia, Canada. It is located within the Selkirk Mountains at the confluence of the Kootenay and Columbia Rivers. It is a regional trade and transportation centre, with a local economy fueled by forestry, mining and tourism...

, located at the Columbia's confluence
Confluence (geography)
In geography, a confluence is the meeting of two or more bodies of water. It usually refers to the point where two streams flow together, merging into a single stream...

 with the Kootenay River
Kootenay River
The Kootenay is a major river in southeastern British Columbia, Canada and the northern part of the U.S. states of Montana and Idaho. It is one of the uppermost major tributaries of the Columbia River, which is the largest North American river that empties into the Pacific Ocean...

, and Trail
Trail, British Columbia
Trail is a city in the West Kootenay region of the Interior of British Columbia, Canada.-Geography:Trail has an area of . The city is located on both banks of the Columbia River, approximately 10 km north of the United States border. This section of the Columbia River valley is located between the...

, two major population centers of the West Kootenay
West Kootenay
West Kootenay was a provincial electoral district in the Canadian province of British Columbia. It was formed along with East Kootenay from a redistribution of the old Kootenay riding, which was one of the province's original twelve.- Demographics :...

 region. The Pend Oreille River
Pend Oreille River
The Pend Oreille River is a tributary of the Columbia River, approximately long, in northern Idaho and northeastern Washington in the United States, as well as southeastern British Columbia in Canada. In its passage through British Columbia its name is spelled Pend-d'Oreille River...

 joins the Columbia about 2 miles (3 km) north of the U.S.–Canada border.

The Columbia enters eastern Washington
Eastern Washington
Eastern Washington is the portion of the U.S. state of Washington east of the Cascade Range. The region contains the city of Spokane , the Tri-Cities, the Columbia River and the Grand Coulee Dam, the Hanford Nuclear Reservation and the fertile farmlands of the Yakima Valley and the...

 flowing south and turning to the west at the Spokane River
Spokane River
The Spokane River is a tributary of the Columbia River, approximately long, in northern Idaho and eastern Washington in the United States. It drains a low mountainous area east of the Columbia, passing through the city of Spokane, Washington.-Description:...

 confluence. It marks the southern and eastern borders of the Colville Indian Reservation
Colville Indian Reservation
The Colville Indian Reservation is an Indian reservation in the north-central part of the U.S. state of Washington, inhabited and managed by the Confederated Tribes of the Colville Reservation, which is recognized by the United States of America as an American Indian Tribe...

 and the western border of the Spokane Indian Reservation. The river turns south after the Okanogan River
Okanogan River
The Okanogan River is a tributary of the Columbia River, approximately 115 mi long, in southern British Columbia and north central Washington...

 confluence, then southeasterly near the confluence with the Wenatchee River
Wenatchee River
The Wenatchee River is a river in the U.S. state of Washington, originating at Lake Wenatchee and flowing southeast for , emptying into the Columbia River immediately north of Wenatchee, Washington...

 in central Washington. This C-shaped segment of the river is also known as the "Big Bend". During the Missoula Floods
Missoula Floods
The Missoula Floods refer to the cataclysmic floods that swept periodically across eastern Washington and down the Columbia River Gorge at the end of the last ice age. The glacial flood events have been researched since the 1920s...

 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
Grand Coulee
The Grand Coulee is an ancient river bed in the U.S. state of Washington. This National Natural Landmark stretches for about sixty miles southwest from Grand Coulee Dam to Soap Lake, being bisected by Dry Falls into the Upper and Lower 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
Grand Coulee Dam
Grand Coulee Dam is a gravity dam on the Columbia River in the U.S. state of Washington built to produce hydroelectric power and provide irrigation. It was constructed between 1933 and 1942, originally with two power plants. A third power station was completed in 1974 to increase its energy...

 in the mid-20th century impounded the river, forming Lake Roosevelt
Franklin D. Roosevelt Lake
Franklin D. Roosevelt Lake is the reservoir created in 1941 by the impoundment of the Columbia River by the Grand Coulee Dam in Washington state. It is named for Franklin D. Roosevelt, who was President during the construction of the dam...

, from which water was pumped into the dry coulee
Coulee
Coulee is applied rather loosely to different landforms, all of which refer to a kind of valley or drainage zone.The word coulee comes from the Canadian French coulée, from French word couler meaning "to flow"....

, forming the reservoir
Reservoir
A reservoir , artificial lake or dam is used to store water.Reservoirs may be created in river valleys by the construction of a dam or may be built by excavation in the ground or by conventional construction techniques such as brickwork or cast concrete.The term reservoir may also be used to...

 of Banks Lake
Banks Lake
Banks Lake is a long reservoir in central Washington in the United States.Part of the Columbia Basin Project, Banks Lake occupies the northern portion of the Grand Coulee, a formerly dry coulee near the Columbia River, formed by the Missoula Floods during the Pleistocene epoch. Grand Coulee Dam,...

.

The river flows past The Gorge Amphitheatre
The Gorge Amphitheatre
The Gorge Amphitheatre is a 20,000+ seat concert venue, located above the Columbia River in George, Washington. It offers lawn-terrace seating and concert-friendly weather....

, a prominent concert venue in the Northwest, then through Priest Rapids Dam
Priest Rapids Dam
Priest Rapids Dam is a hydroelectric, concrete gravity dam; located on the Columbia River, between the Yakima Firing Range and the Hanford Nuclear Reservation, and bridges Yakima County and Grant County, in the U.S. state of Washington. The dam is 24 miles south of the town of Vantage, and 47 miles...

, and then through the Hanford Nuclear Reservation
Hanford Site
The Hanford Site is a mostly decommissioned nuclear production complex on the Columbia River in the U.S. state of Washington, operated by the United States federal government. The site has been known by many names, including Hanford Works, Hanford Engineer Works or HEW, Hanford Nuclear Reservation...

. Entirely within the reservation is Hanford Reach
Hanford Reach
The Hanford Reach is a free-flowing section of the Columbia River, about long, in eastern Washington state, named after a large northward bend in the river's otherwise southbound course. It is the only section of the Columbia in the U.S...

, the only U.S. stretch of the river that is completely free-flowing, unimpeded by dams and not a tidal estuary
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....

. The Snake River
Snake River
The Snake is a major river of the greater Pacific Northwest in the United States. At long, it is the largest tributary of the Columbia River, the largest North American river that empties into the Pacific Ocean...

 and Yakima River
Yakima River
The Yakima River is a tributary of the Columbia River in south central and eastern Washington State, named for the indigenous Yakama people. The length of the river from headwaters to mouth is , with an average drop of .-Course:...

 join the Columbia in the Tri-Cities
Tri-Cities, Washington
The Tri-Cities is a mid-sized metropolitan area in the southeastern part of the U.S. state of Washington, consisting of three neighboring cities: Kennewick, Pasco, and Richland. The cities are located at the confluence of the Yakima, Snake, and Columbia rivers in the semi-arid region of...

 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 (497.3 km) of its journey.
The Deschutes River joins the Columbia near The Dalles
The Dalles, Oregon
The Dalles is the largest city and county seat of Wasco County, Oregon, United States. The name of the city comes from the French word dalle The Dalles is the largest city and county seat of Wasco County, Oregon, United States. The name of the city comes from the French word dalle The Dalles is...

. Between The Dalles and Portland
Portland, Oregon
Portland is a city located in the Pacific Northwest, near the confluence of the Willamette and Columbia rivers in the U.S. state of Oregon. As of the 2010 Census, it had a population of 583,776, making it the 29th most populous city in the United States...

, the river cuts through the Cascade Range
Cascade Range
The Cascade Range is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, and the notable volcanoes known as the High Cascades...

, forming the dramatic Columbia River Gorge
Columbia River Gorge
The Columbia River Gorge is a canyon of the Columbia River in the Pacific Northwest of the United States. Up to deep, the canyon stretches for over as the river winds westward through the Cascade Range forming the boundary between the State of Washington to the north and Oregon to the south...

. No other river except for the Klamath
Klamath River
The Klamath River is an American river that flows southwest through Oregon and northern California, cutting through the Cascade Range to empty into the Pacific Ocean. The river drains an extensive watershed of almost that stretches from the high desert country of the Great Basin to the temperate...

 completely breaches the Cascades—the other rivers that flow through the range also originate in or very near the mountains. The headwaters and upper course of the Pit River
Pit River
The Pit River is a major river draining from northeastern California into the state's Central Valley. The Pit, the Klamath and the Columbia are the only three rivers in the U.S...

 flows through much of the Cascades; in contrast the Columbia cuts through the range nearly a thousand miles from its source in the Rocky Mountains. 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
Vancouver, Washington
Vancouver is a city on the north bank of the Columbia River in the U.S. state of Washington. Incorporated in 1857, it is the fourth largest city in the state with a 2010 census population of 161,791 as of April 1, 2010...

, at the Willamette River
Willamette River
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 long, lying entirely in northwestern Oregon in the United States...

 confluence. Here the river slows considerably, dropping sediment that might otherwise form a river delta
River delta
A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...

. Near Longview, Washington
Longview, Washington
Longview is a city in Cowlitz County, Washington, United States. It is the principal city of the "Longview, Washington Metropolitan Statistical Area", which encompasses all of Cowlitz County. Longview's population was 36,648 at the time of the 2010 census and is the largest city in Cowlitz County...

 and the Cowlitz River
Cowlitz River
The Cowlitz River is a river in the state of Washington in the United States, a tributary of the Columbia River. Its tributaries drain a large region including the slopes of Mount Rainier, Mount Adams, and Mount St. Helens....

 confluence, the river turns west again. The Columbia empties into the Pacific Ocean just west of Astoria, Oregon
Astoria, Oregon
Astoria is the county seat of Clatsop County, Oregon, United States. Situated near the mouth of the Columbia River, the city was named after the American investor John Jacob Astor. His American Fur Company founded Fort Astoria at the site in 1811...

, over the Columbia Bar
Columbia Bar
The Columbia Bar is a system of bars and shoals at the mouth of the Columbia River spanning the US states of Oregon and Washington. The bar is about wide and long....

, a shifting sandbar that makes the river's mouth one of the most hazardous stretches of water to navigate in the world.

The Columbia drains an area of about 258000 mi2. Its drainage basin covers nearly all of Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....

, large portions of British Columbia, Oregon, and Washington, and small portions of Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...

, Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...

, Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...

, and Nevada
Nevada
Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...

; the total area is similar to the size of France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

. Roughly 745 miles (1,199 km) of the river's length and 85 percent of its drainage basin are in the U.S. The Columbia is the twelfth-longest river and has the sixth-largest drainage basin in the U.S. In Canada, where the Columbia flows for 498 miles (801.5 km) and drains 39700 mi2, the river ranks 23rd in length, and its basin ranks 13th in size.
The Columbia shares its name with nearby places, such as British Columbia, as well as with landforms and bodies of water.

Discharge

With an average flow at the mouth of about 265000 ft3/s, the Columbia is the largest river by volume flowing into the Pacific from North America and is the fourth-largest by volume in the U.S. The average flow where the river crosses the international boundary between Canada and the U.S. is 99000 ft3/s from a drainage basin of 39700 mi2. This amounts to about 15 percent of the entire Columbia watershed. The Columbia's highest recorded flow, measured at The Dalles, was 1240000 ft3/s in June 1894, before the river was dammed. The lowest flow recorded at The Dalles was 12100 ft3/s on April 16, 1968, and was caused by the initial closure of the John Day Dam
John Day Dam
The John Day Dam is a concrete gravity run-of-the-river dam spanning the Columbia River in the northwestern United States. The dam features a navigation lock plus fish ladders on both sides. The John Day Lock has the highest lift of any U.S. lock...

, 28 miles (45.1 km) upstream. The Dalles is about 190 miles (305.8 km) from the mouth; the river at this point drains about 237000 mi2 or about 91 percent of the total watershed. Flow rates on the Columbia are affected by many large upstream reservoirs, many diversions for irrigation, and, on the lower stretches, reverse flow from the tide
Tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the moon and the sun and the rotation of the Earth....

s of the Pacific Ocean. The National Weather Service
National Weather Service
The National Weather Service , once known as the Weather Bureau, is one of the six scientific agencies that make up the National Oceanic and Atmospheric Administration of the United States government...

 issues tide forecasts for eight places along the river between Astoria and the base of Bonneville Dam
Bonneville Dam
Bonneville Lock and Dam consists of several run-of-the-river dam structures that together complete a span of the Columbia River between the U.S. states of Oregon and Washington at River Mile 146.1. The dam is located east of Portland, Oregon, in the Columbia River Gorge. The primary functions of...

.

Geology

When the rift
Rift
In geology, a rift or chasm is a place where the Earth's crust and lithosphere are being pulled apart and is an example of extensional tectonics....

ing of Pangea, due to the process of plate tectonics
Plate tectonics
Plate tectonics is a scientific theory that describes the large scale motions of Earth's lithosphere...

, pushed North America away from Europe and Africa and into the Panthalassic Ocean (ancestor to the modern Pacific Ocean), the Pacific Northwest was not part of the continent. As the North American continent moved westward, the Farallon Plate
Farallon Plate
The Farallon Plate was an ancient oceanic plate, which began subducting under the west coast of the North American Plate— then located in modern Utah— as Pangaea broke apart during the Jurassic Period...

 subducted
Subduction
In geology, subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate, sinking into the Earth's mantle, as the plates converge. These 3D regions of mantle downwellings are known as "Subduction Zones"...

 under its western margin. As the plate subducted, it carried along island arc
Island arc
An island arc is a type of archipelago composed of a chain of volcanoes which alignment is arc-shaped, and which are situated parallel and close to a boundary between two converging tectonic plates....

s which were accreted to the North American continent, resulting in the creation of the Pacific Northwest between 150 and 90 million years ago. The general outline of the Columbia Basin was not complete until between 60 and 40 million years ago, but it lay under a large inland sea later subject to uplift. Between 40 and 20 million years ago, in the Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...

 and Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

 eras, tremendous volcanic eruptions frequently modified much of the landscape traversed by the Columbia. The lower reaches of the ancestral river passed through a valley near where Mount Hood
Mount Hood
Mount Hood, called Wy'east by the Multnomah tribe, is a stratovolcano in the Cascade Volcanic Arc of northern Oregon. It was formed by a subduction zone and rests in the Pacific Northwest region of the United States...

 later arose. Carrying sediments from erosion and erupting volcanoes, it built a 2 miles (3.2 km) thick delta
River delta
A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...

 that underlies the foothills on the east side of the Coast Range
Northern Oregon Coast Range
The Northern Oregon Coast Range is the northern section of the Oregon Coast Range, in the Pacific Coast Ranges physiographic region, located in the northwest portion of the state of Oregon, United States. This section of the mountain range, part of the Pacific Coast Ranges, contains peaks as high...

 near Vernonia
Vernonia, Oregon
Vernonia is a city in Columbia County, Oregon, United States. The city is located on the Nehalem River, in a valley on the eastern side of the Northern Oregon Coast Range. It is located the heart of the most important timber-producing areas of the state, and logging has played an important role in...

 in northwestern Oregon. Between 17 million and 6 million years ago, huge outpourings of flood basalt
Flood basalt
A flood basalt or trap basalt is the result of a giant volcanic eruption or series of eruptions that coats large stretches of land or the ocean floor with basalt lava. Flood basalts have occurred on continental scales in prehistory, creating great plateaus and mountain ranges...

 lava covered the Columbia River Plateau
Columbia River Plateau
The Columbia Plateau is a geologic and geographic region that lies across parts of the U.S. states of Washington, Oregon, and Idaho. It is a wide flood basalt plateau between the Cascade Range and the Rocky Mountains, cut through by the Columbia River...

 and forced the lower Columbia into its present course. The Cascade Range
Cascade Range
The Cascade Range is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, and the notable volcanoes known as the High Cascades...

 began to uplift during the early Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....

 era (two million to 700,000 years ago). Cutting through the uplifting mountains, the Columbia River created the Columbia River Gorge
Columbia River Gorge
The Columbia River Gorge is a canyon of the Columbia River in the Pacific Northwest of the United States. Up to deep, the canyon stretches for over as the river winds westward through the Cascade Range forming the boundary between the State of Washington to the north and Oregon to the south...

.

The river and its drainage basin
Columbia Basin
The Columbia Basin, the drainage basin of the Columbia River, occupies a large area–about —of the Pacific Northwest region of North America. In common usage, the term often refers to a smaller area, generally the portion of the drainage basin that lies within eastern Washington.Usage of the term...

 experienced some of the world's greatest known catastrophic floods toward the end of the last ice age
Ice age
An ice age or, more precisely, glacial age, is a generic geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental ice sheets, polar ice sheets and alpine glaciers...

. The periodic rupturing of ice dams at Glacial Lake Missoula
Glacial Lake Missoula
Glacial Lake Missoula was a prehistoric proglacial lake in western Montana that existed periodically at the end of the last ice age between 15,000 and 13,000 years ago...

 resulted in the Missoula Floods
Missoula Floods
The Missoula Floods refer to the cataclysmic floods that swept periodically across eastern Washington and down the Columbia River Gorge at the end of the last ice age. The glacial flood events have been researched since the 1920s...

, with discharges 10 times the combined flow of all the rivers of the world, dozens of times over thousands of years. The exact number of floods is unknown, but geologists have documented at least 40; evidence suggests that they occurred between about 19,000 and 13,000 years ago.
The floodwaters rushed across eastern Washington, creating the channeled scablands
Channeled scablands
The Channeled Scablands are a unique geological erosion feature in the U.S. state of Washington. They were created by the cataclysmic Missoula Floods that swept periodically across eastern Washington and down the Columbia River Plateau during the Pleistocene epoch. Geologist J Harlen Bretz coined...

, which are a complex network of dry canyon-like channels, or coulees that are often braided
Braided river
A braided river is one of a number of channel types and has a channel that consists of a network of small channels separated by small and often temporary islands called braid bars or, in British usage, aits or eyots. Braided streams occur in rivers with high slope and/or large sediment load...

 and sharply gouged into the basalt rock underlying the region's deep topsoil. Numerous flat-topped butte
Butte
A butte is a conspicuous isolated hill with steep, often vertical sides and a small, relatively flat top; it is smaller than mesas, plateaus, and table landform tables. In some regions, such as the north central and northwestern United States, the word is used for any hill...

s 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
Lake Lewis
Lake Lewis was a temporary lake in the Pacific Northwest region of North America, largely formed by the Missoula Floods in about the 14th millennium B.C....

, in which sediments were deposited. Water depths have been estimated at 1250 feet (381 m) at Wallula Gap
Wallula Gap
Wallula Gap is a large water gap of the Columbia River through basalt anticlines in the Columbia River Basin in the U.S. state of Washington, just south of the confluence of the Walla Walla and Columbia rivers...

, 830 feet (253 m) at Bonneville Dam
Bonneville Dam
Bonneville Lock and Dam consists of several run-of-the-river dam structures that together complete a span of the Columbia River between the U.S. states of Oregon and Washington at River Mile 146.1. The dam is located east of Portland, Oregon, in the Columbia River Gorge. The primary functions of...

, and 400 feet (121.9 m) over modern Portland
Portland, Oregon
Portland is a city located in the Pacific Northwest, near the confluence of the Willamette and Columbia rivers in the U.S. state of Oregon. As of the 2010 Census, it had a population of 583,776, making it the 29th most populous city in the United States...

, Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...

. 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
Columbia River Plateau
The Columbia Plateau is a geologic and geographic region that lies across parts of the U.S. states of Washington, Oregon, and Idaho. It is a wide flood basalt plateau between the Cascade Range and the Rocky Mountains, cut through by the Columbia River...

 deposited rich sediments; 21st-century farmers in the Willamette Valley "plow fields of fertile Montana soil and clays from Washington's Palouse".

Over the last several thousand years a series of large landslides have occurred on the north side of the Columbia River Gorge, sending massive amounts of debris south from Table Mountain and Greenleaf Peak
Greenleaf Peak
Greenleaf Peak is a mountain in the Cascade Range in the U.S. state of Washington, located on the north side of the Columbia River near Table Mountain, in the Columbia River Gorge. The peak lies within the Columbia River Gorge National Scenic Area near Bonneville Dam. It is in elevation...

 into the gorge near the present site of Bonneville Dam. The most recent and significant is known as the Bonneville Slide, which formed a massive earthen dam, filling 3.5 miles (5.6 km) of the river's length. Various studies have placed the date of the Bonneville Slide anywhere between 1060 and 1760 AD; the idea that the landslide debris present today was formed by more than one slide is relatively recent and may explain the large range of estimates. It has been suggested that if the later dates are accurate there may be a link with the 1700 Cascadia earthquake. The pile of debris resulting from the Bonneville Slide blocked the river until rising water finally washed away the sediment. It is not known how long it took the river to break through the barrier; estimates range from several months to several years. Much of the landslide's debris remained, forcing the river about 1.5 miles (2.4 km) south of its previous channel and forming the Cascade Rapids. In 1938, the construction of Bonneville Dam inundated the rapids as well as the remaining trees that could be used to refine the estimated date of the landslide.

In 1980, the eruption of Mount St. Helens
1980 eruption of Mount St. Helens
The 1980 eruption of Mount St. Helens, a stratovolcano located in Washington state, in the United States, was a major volcanic eruption. The eruption was the only significant one to occur in the contiguous 48 U.S. states since the 1915 eruption of Lassen Peak in California...

 deposited large amounts of sediment in the lower Columbia, temporarily reducing the depth of the shipping channel by 26 feet (7.9 m).

Indigenous peoples

Humans have inhabited the Columbia's watershed 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
Marmes Rockshelter
The Marmes Rockshelter is an archaeological site first excavated in 1962, near the confluence of the Snake and Palouse Rivers, in Franklin County, southeastern Washington. This rockshelter is remarkable in the level of preservation of organic materials, the depth of stratified deposits, and the...

, near the confluence of the Palouse
Palouse River
The Palouse River is a tributary of the Snake River located in the U.S. states of Washington and Idaho. It flows for southwestwards, primarily through the Palouse region of southeastern Washington...

 and Snake
Snake River
The Snake is a major river of the greater Pacific Northwest in the United States. At long, it is the largest tributary of the Columbia River, the largest North American river that empties into the Pacific Ocean...

 rivers in eastern Washington. In 1996, the skeletal remains of a 9,000-year-old prehistoric man (dubbed Kennewick Man
Kennewick Man
Kennewick Man is the name for the skeletal remains of a prehistoric man found on a bank of the Columbia River in Kennewick, Washington, USA, on July 28, 1996...

) were found near Kennewick, Washington
Kennewick, Washington
Kennewick is a city in Benton County in the southeastern part of the U.S. state of Washington, near the Hanford nuclear site. It is the most populous of the three cities collectively referred to as the Tri-Cities...

. 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
Native Americans in the United States
Native Americans in the United States are the indigenous peoples in North America within the boundaries of the present-day continental United States, parts of Alaska, and the island state of Hawaii. They are composed of numerous, distinct tribes, states, and ethnic groups, many of which survive as...

 community was entitled to possess and/or study the remains.

Many different Native Americans and First Nations
First Nations
First Nations is a term that collectively refers to various Aboriginal peoples in Canada who are neither Inuit nor Métis. There are currently over 630 recognised First Nations governments or bands spread across Canada, roughly half of which are in the provinces of Ontario and British Columbia. The...

 peoples have a historical and continuing presence on the Columbia. The Sinixt
Sinixt
The Sinixt are a First Nations People...

 or Lakes people lived on the lower stretch of the Canadian portion (also claimed as part of Okanagan
Okanagan people
The Okanagan people, also spelled Okanogan, are a First Nations and Native American people whose traditional territory spans the U.S.-Canada boundary in Washington state and British Columbia...

 territory) the Secwepemc
Secwepemc
The Secwepemc , known in English as the Shuswap people, are a First Nations people residing in the Canadian province of British Columbia. Their traditional territory ranges from the eastern Chilcotin Plateau and the Cariboo Plateau southeast through the Thompson Country to Kamloops and the Shuswap...

, Ktunaxa and at one time the Blackfoot on the upper; the Colville
Colville (tribe)
The Colville tribe is a Native American tribe of the Pacific Northwest. The name Colville comes from association with Fort Colville, named after Andrew Colvile of the Hudson's Bay Company...

, Spokane
Spokane (tribe)
The Spokane are a Native American people in the northeastern portion of the U.S. state of Washington. The Spokane Indian Reservation, at , is located in eastern Washington, almost entirely in Stevens County, but includes two very small parcels of land and part of the Spokane River in...

, Coeur d'Alene
Coeur d'Alene Tribe
The Coeur d'Alene are a Native American people who lived in villages along the Coeur d'Alene, St. Joe, Clark Fork and Spokane Rivers; as well as sites on the shores of Lake Coeur d'Alene, Lake Pend Oreille and Hayden Lake, in what is now northern Idaho, eastern Washington and western Montana.In...

, Yakama
Yakama
The Confederated Tribes and Bands of the Yakama Nation, or simply Yakama Nation , is a Native American group with nearly 10,000 enrolled members, living in Washington. Their reservation, along the Yakima River, covers an area of approximately 1.2 million acres...

, Nez Perce, Cayuse
Cayuse
The Cayuse are a Native American tribe in the state of Oregon in the United States. The Cayuse tribe shares a reservation in northeastern Oregon with the Umatilla and the Walla Walla tribes as part of the Confederated Tribes of the Umatilla Indian Reservation...

, Palus
Palus (tribe)
The Palus are a Sahaptin tribe recognized in the Treaty of 1855 with the Yakamas . A variant spelling is Palouse, which was the source of the name for the fertile prairie of Washington and Idaho.- Ethnography :...

, Umatilla
Umatilla (tribe)
The Umatilla are a Sahaptin-speaking Native American group living on the Umatilla Indian Reservation, who traditionally inhabited the Columbia Plateau region of the northwestern United States....

, Cowlitz
Cowlitz (tribe)
The Cowlitz are a group of Native American peoples from what is now western Washington state in the United States. The Cowlitz tribe actually consists of two distinct groups: the Upper Cowlitz, or Taidnapam, and the Lower Cowlitz, or Kawlic....

, and the Confederated Tribes of Warm Springs
Confederated Tribes of Warm Springs
The Confederated Tribes of Warm Springs is a federally recognized confederation of Native American Tribes who currently live on and govern the Warm Springs Indian Reservation in the U.S...

 live along the U.S. stretch. Along the upper Snake River and Salmon River
Salmon River (Idaho)
The Salmon River is located in Idaho in the northwestern United States. The Salmon is also known as The River of No Return. It flows for through central Idaho, draining and dropping more than between its headwaters, near Galena Summit above the Sawtooth Valley in the Sawtooth National...

, the Shoshone
Shoshone
The Shoshone or Shoshoni are a Native American tribe in the United States with three large divisions: the Northern, the Western and the Eastern....

 Bannock
Bannock (tribe)
The Bannock tribe of the Northern Paiute are an indigenous people of the Great Basin. Their traditional lands include southeastern Oregon, southeastern Idaho, western Wyoming, and southwestern Montana...

 tribes are present. The Chinook
Chinookan
Chinook refers to several native amercain groups of in the Pacific Northwest region of the United States, speaking the Chinookan languages. In the early 19th century, the Chinookan-speaking peoples lived along the lower and middle Columbia River in present-day Oregon and Washington...

 tribe, which is not federally recognized, also live near the lower Columbia River. The river is known as Wimahl to the Chinook-speaking natives of its lower reaches, and Nch’i-Wàna to the Sahaptin
Sahaptin language
Sahaptin , Sħáptənəxw, is a Plateau Penutian language of the Sahaptian branch spoken in a section of the northwestern plateau along the Columbia River and its tributaries in southern Washington, northern Oregon, and southwestern Idaho....

-speaking peoples of its middle course in present-day Washington; both terms essentially mean "the big river".

Oral histories describe the formation and destruction of the Bridge of the Gods
Bridge of the Gods (geologic event)
The Bridge of the Gods was a natural dam created by the Bonneville Slide, a major landslide that dammed the Columbia River near present-day Cascade Locks, Oregon in the Pacific Northwest of the United States...

, a land bridge that connected the Oregon and Washington sides of the river in the Columbia River Gorge. The bridge, which aligns with geological records of the Bonneville Slide, was described in some stories as the result of a battle between gods, represented by Mount Adams
Mount Adams (Washington)
Mount Adams is a potentially activestratovolcano in the Cascade Range and the second-highest mountain in the U.S. state of Washington.Adams is a member of the Cascade Volcanic Arc, and is one of the arc's largest volcanoes,...

 and Mount Hood
Mount Hood
Mount Hood, called Wy'east by the Multnomah tribe, is a stratovolcano in the Cascade Volcanic Arc of northern Oregon. It was formed by a subduction zone and rests in the Pacific Northwest region of the United States...

, in their competition for the affection of a goddess, represented by Mount St. Helens
Mount St. Helens
Mount St. Helens is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States. It is south of Seattle, Washington and northeast of Portland, Oregon. Mount St. Helens takes its English name from the British diplomat Lord St Helens, a...

. Native American stories about the bridge differ in their details but agree in general that the bridge permitted increased interaction between tribes on the north and south sides of the river.

Horses, originally acquired from Spanish New Mexico
Santa Fe de Nuevo México
Santa Fe de Nuevo México was a province of New Spain and later Mexico that existed from the late 16th century up through the mid-19th century. It was centered on the upper valley of the Rio Grande , in an area that included most of the present-day U.S. state of New Mexico...

, spread widely via native trade networks, reaching the Shoshone of the Snake River Plain
Snake River Plain
The Snake River Plain is a geologic feature located primarily within the state of Idaho in the United States of America. It stretches about westward from northwest of the state of Wyoming to the Idaho-Oregon border. The plain is a wide flat bow-shaped depression, and covers about a quarter of Idaho...

 by 1700. The Nez Perce, Cayuse, and Flathead
Confederated Salish and Kootenai Tribes of the Flathead Nation
The Confederated Salish and Kootenai Tribes of the Flathead Reservation are the Bitterroot Salish, Kootenai and Pend d'Oreilles Tribes. The Flatheads lived between the Cascade Mountains and Rocky Mountains. The Salish initially lived entirely east of the Continental Divide but established their...

 people acquired their first horses around 1730. Along with horses came aspects of the emerging plains culture, such as equestrian and horse training
Horse training
Horse training refers to a variety of practices that teach horses to perform certain behaviors when asked to do so by humans. Horses are trained to be manageable by humans for everyday care as well as for equestrian activities from horse racing to therapeutic horseback riding for people with...

 skills, greatly increased mobility, hunting efficiency, trade over long distances, intensified warfare, the linking of wealth and prestige to horses and war, and the rise of large and powerful tribal confederacies. The Nez Perce and Cayuse kept large herds and made annual long-distance trips to the Great Plains
Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...

 for bison
Bison
Members of the genus Bison are large, even-toed ungulates within the subfamily Bovinae. Two extant and four extinct species are recognized...

 hunting, adopted the plains culture to a significant degree, and became the main conduit through which horses and the plains culture diffused into the Columbia River region. Other peoples acquired horses and aspects of the plains culture unevenly. The Yakama, Umatilla, Palus, Spokane, and Coeur d'Alene maintained sizable herds of horses and adopted some of the plains cultural characteristics, but fishing and fish-related economies remained important. Less affected groups included the Molala
Molala
The Molala were a people of the Plateau culture area in central Oregon, United States. Some consider them extinct, though they are one of the Confederated Tribes of the Grand Ronde Community of Oregon, with 141 of the 882 members in the 1950s claiming Molala descent.-Language:The Molalla language...

, Klickitat, Wenatchi
Wenatchi
The Wenatchi Tribe is a group of Native Americans who lived in the region near the confluence of the Columbia and Wenatchee Rivers in Eastern Washington State...

, Okanagan, and Sinkiuse-Columbia
Sinkiuse-Columbia
The Sinkiuse-Columbia were a Native American tribe so-called because of their former prominent association with the Columbia River. They called themselves .tskowa'xtsEnux, or .skowa'xtsEnEx , or Sinkiuse. They applied the name also to other neighboring Interior Salish peoples...

 peoples, who owned small numbers of horses and adopted few plains culture features. Some groups remained essentially unaffected, such as the Sanpoil
Sanpoil (tribe)
The Sanpoil is one of 12 aboriginal Confederated Tribes of the Colville Indian Reservation. The name Sanpoil comes from the Okanagan [snpʕwílx], "gray as far as one can see". It has been folk-etymologized as coming from the French sans poil, "without fur". The Yakama people know the tribe as...

 and Nespelem
Nespelem (tribe)
The Nespelem people belong to one of 12 aboriginal Confederated Tribes of the Colville Indian Reservation in eastern Washington. They lived primarily near the banks of the Nespelem River, an Upper Columbia River tributary, in an area now known as Nespelem, Washington, located on the Colville Indian...

 people, whose culture remained centered on fishing.

Natives of the region encountered foreigners at several times and places during the 18th and 19th centuries. European and American vessels explored the coastal area around the mouth of the river in the late 18th century, trading with local natives. The contact would prove devastating to the Indian tribes; a large portion of their population was wiped out by a smallpox
Smallpox
Smallpox was an infectious disease unique to humans, caused by either of two virus variants, Variola major and Variola minor. The disease is also known by the Latin names Variola or Variola vera, which is a derivative of the Latin varius, meaning "spotted", or varus, meaning "pimple"...

 epidemic. Canadian explorer Alexander Mackenzie crossed what is now interior British Columbia in 1793. In 1805–07, the Lewis and Clark Expedition
Lewis and Clark Expedition
The Lewis and Clark Expedition, or ″Corps of Discovery Expedition" was the first transcontinental expedition to the Pacific Coast by the United States. Commissioned by President Thomas Jefferson and led by two Virginia-born veterans of Indian wars in the Ohio Valley, Meriwether Lewis and William...

 entered the Oregon Country
Oregon Country
The Oregon Country was a predominantly American term referring to a disputed ownership region of the Pacific Northwest of North America. The region was occupied by British and French Canadian fur traders from before 1810, and American settlers from the mid-1830s, with its coastal areas north from...

 along the Clearwater
Clearwater River (Idaho)
The Clearwater River is a river in north central Idaho, which flows westward from the Bitterroot Mountains along the Idaho-Montana border, and joins the Snake River at Lewiston. In October 1805, the Lewis and Clark Expedition descended the Clearwater River in dugout canoes, putting in at "Canoe...

 and Snake Rivers, and encountered numerous small settlements of natives. Their records recount tales of hospitable traders who were not above stealing small items from the visitors. They also noted brass teakettles, a British musket, and other artifacts that had been obtained in trade with coastal tribes. From the earliest contact with westerners, the natives of the mid- and lower Columbia were not tribal, but instead congregated in social units no larger than a village, and more often at a family level; these units would shift with the season as people moved about, following the salmon catch up and down the river's tributaries.

Sparked by the 1848 Whitman Massacre
Whitman massacre
The Whitman massacre was the murder in the Oregon Country on November 29, 1847 of U.S. missionaries Dr. Marcus Whitman and his wife Narcissa Whitman, along with eleven others. They were killed by Cayuse and Umatilla Indians. The incident began the Cayuse War...

, a number of violent battles were fought between American settlers and the region's natives. The subsequent Indian Wars, notably the Yakima War
Yakima War
The Yakima War was a conflict between the United States and the Yakama, a Sahaptian-speaking people on the Northwest Plateau, then Washington Territory and now the southern interior of Eastern Washington, from 1855 to 1858.- Naming :...

, decimated the native population and removed much land from native control. As years progressed, the right of natives to fish along the Columbia became the central issue of contention with the states, commercial fishers, and private property owners. The U.S. Supreme Court upheld fishing rights in landmark cases in 1905 and 1918.
Fish were central to the culture of the region's natives, both as sustenance and as part of their religious beliefs. Natives drew fish from the Columbia at several major sites, which also served as trading posts. Celilo Falls
Celilo Falls
Celilo Falls was a tribal fishing area on the Columbia River, just east of the Cascade Mountains, on what is today the border between the U.S. states of Oregon and Washington...

, located east of the modern city of The Dalles, was a vital hub for trade and the interaction of different cultural groups, being used for fishing and trading for 11,000 years. Prior to contact with westerners, villages along this 9 miles (14.5 km) stretch may have at times had a population as great as 10,000. The site drew traders from as far away as the Great Plains
Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...

. The Cascades Rapids
Cascades Rapids
The Cascades Rapids were an area of rapids along North America's Columbia River, between the U.S. states of Washington and Oregon. Through a stretch approximately wide, the river dropped about in .-Boat portage:Boat travelers were forced to either portage boats and supplies or pull boats up with...

 of the Columbia River Gorge, and Kettle Falls
Kettle Falls
Kettle Falls was an ancient and important salmon fishing site on the upper reaches of the Columbia River, in what is today the U.S. state of Washington, near the Canadian border...

 and Priest Rapids
Priest Rapids
Priest Rapids was a narrow, fast-flowing stretch of the Columbia River, located in the central region of the U.S. state of Washington. It was flooded by the construction of the Priest Rapids Dam in the 1950s....

 in eastern Washington, were also major fishing and trading sites.

In prehistoric times the Columbia's salmon and steelhead runs numbered an estimated annual average of 10 to 16 million fish. In comparison, the largest run since 1938 was in 1986, with 3.2 million fish entering the Columbia. The annual catch by natives has been estimated at 42 million pounds (19,000 t). The most important and productive native fishing site was located at Celilo Falls, which was perhaps the most productive inland fishing site in North America. The falls were located at the border between Chinookan
Chinookan languages
Chinookan is a small family of languages spoken in Oregon and Washington along the Columbia River by Chinook peoples.-Family division:Chinookan languages consists of three languages with multiple varieties. There is some dispute over classification, and there are two ISO 639-3 codes assigned: and...

- and Sahaptian-speaking peoples and served as the center of an extensive trading network across the Pacific Plateau. Celilo was the oldest continuously inhabited community on the North American continent.

Salmon canneries established by white settlers beginning in 1867 had a strong negative impact on the salmon population, and in 1908 U.S. President Theodore Roosevelt
Theodore Roosevelt
Theodore "Teddy" Roosevelt was the 26th President of the United States . He is noted for his exuberant personality, range of interests and achievements, and his leadership of the Progressive Movement, as well as his "cowboy" persona and robust masculinity...

 observed that the salmon runs were but a fraction of what they had been 25 years prior. Still, in the 1930s, there were natives who lived along the river and fished year round, moving along with the fish's migration patterns throughout the seasons.

As river development continued in the 20th century, each of these major fishing sites was flooded by a dam, beginning with Cascades Rapids in 1938. The development was accompanied by extensive negotiations between natives and U.S. government agencies. The Confederated Tribes of Warm Springs
Confederated Tribes of Warm Springs
The Confederated Tribes of Warm Springs is a federally recognized confederation of Native American Tribes who currently live on and govern the Warm Springs Indian Reservation in the U.S...

, a coalition of various tribes, adopted a constitution and incorporated after the 1938 completion of the Bonneville Dam
Bonneville Dam
Bonneville Lock and Dam consists of several run-of-the-river dam structures that together complete a span of the Columbia River between the U.S. states of Oregon and Washington at River Mile 146.1. The dam is located east of Portland, Oregon, in the Columbia River Gorge. The primary functions of...

 flooded Cascades Rapids; the Yakama
Yakama
The Confederated Tribes and Bands of the Yakama Nation, or simply Yakama Nation , is a Native American group with nearly 10,000 enrolled members, living in Washington. Their reservation, along the Yakima River, covers an area of approximately 1.2 million acres...

 were slower to do so, organizing a formal government in 1944. Today, the Yakama, Nez Perce, Umatilla, and Warm Springs tribes all have treaty fishing rights along the Columbia and its tributaries.

In 1957 Celilo Falls 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-Ta resort south of Mount Hood
Mount Hood
Mount Hood, called Wy'east by the Multnomah tribe, is a stratovolcano in the Cascade Volcanic Arc of northern Oregon. It was formed by a subduction zone and rests in the Pacific Northwest region of the United States...

.

New waves of explorers

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
Clatsop
The Clatsop are a small tribe of Chinookan-speaking Native Americans in the Pacific Northwest of the United States. In the early 19th century they inhabited an area of the northwestern coast of present-day Oregon from the mouth of the Columbia River south to Tillamook.-Language:Clatsop in the...

; if these were indeed the first Europeans to see the Columbia, they failed to send word home to Spain.

In the 18th century, there was strong interest in discovering a Northwest Passage
Northwest Passage
The Northwest Passage is a sea route through the Arctic Ocean, along the northern coast of North America via waterways amidst the Canadian Arctic Archipelago, connecting the Atlantic and Pacific Oceans...

 that would permit navigation between the Atlantic (or inland North America) and the Pacific Ocean. Many ships in the area, especially those under Spanish and British command, searched the northwest coast for a large river that might connect to Hudson Bay
Hudson Bay
Hudson Bay , sometimes called Hudson's Bay, is a large body of saltwater in northeastern Canada. It drains a very large area, about , that includes parts of Ontario, Quebec, Saskatchewan, Alberta, most of Manitoba, southeastern Nunavut, as well as parts of North Dakota, South Dakota, Minnesota,...

 or the Missouri River
Missouri River
The Missouri River flows through the central United States, and is a tributary of the Mississippi River. It is the longest river in North America and drains the third largest area, though only the thirteenth largest by discharge. The Missouri's watershed encompasses most of the American Great...

. The first documented European discovery of the Columbia River was that of Bruno de Heceta
Bruno de Heceta
Bruno de Heceta y Dudagoitia was a Spanish Basque explorer of the Pacific Northwest. Born in Bilbao of an old Basque family, he was sent by the Viceroy of New Spain, Antonio María Bucareli y Ursúa, to explore the area north of Alta California in response to information that there were colonial...

, 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 maritime fur trade
Maritime Fur Trade
The Maritime Fur Trade was a ship-based fur trade system that focused on acquiring furs of sea otters and other animals from the indigenous peoples of the Pacific Northwest Coast and natives of Alaska. The furs were mostly sold in China in exchange for tea, silks, porcelain, and other Chinese...

r Captain John Meares
John Meares
John Meares was a navigator, explorer, and maritime fur trader, best known for his role in the Nootka Crisis, which brought Britain and Spain to the brink of war.- Career :...

 searched for the river in 1788 but concluded that it did not exist. He named Cape Disappointment
Cape Disappointment (Washington)
Cape Disappointment is a headland located at the extreme southwestern corner of Washington State on the north side of the Columbia River bar, at . The point of the cape is located on the Pacific Ocean in Pacific County, approximately two miles southwest of the town of Ilwaco...

 for the non-existent river, not realizing the cape marks the northern edge of the river's mouth.

What happened next would form the basis for decades of both cooperation and dispute between British and American exploration of, and ownership claim to, the region. Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 commander George Vancouver
George Vancouver
Captain George Vancouver RN was an English officer of the British Royal Navy, best known for his 1791-95 expedition, which explored and charted North America's northwestern Pacific Coast regions, including the coasts of contemporary Alaska, British Columbia, Washington and Oregon...

 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
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 captain Robert Gray at the Strait of Juan de Fuca
Strait of Juan de Fuca
The Strait of Juan de Fuca is a large body of water about long that is the Salish Sea outlet to the Pacific Ocean...

. Gray reported that he had seen the entrance to the Columbia and had spent nine days trying but failing to enter.

On May 12, 1792, Gray returned south and crossed the Columbia Bar
Columbia Bar
The Columbia Bar is a system of bars and shoals at the mouth of the Columbia River spanning the US states of Oregon and Washington. The bar is about wide and long....

, becoming the first explorer to enter the river
Gray sails the Columbia River
In May of 1792, American merchant sea captain Robert Gray sailed into the Columbia River, becoming the first recorded European to navigate into it. The voyage, conducted on the Columbia Rediviva, a privately owned ship, was eventually used as a basis for the United States' claim on the Pacific...

. Gray's fur trading mission had been financed by Boston merchants, who outfitted him with a private vessel named Columbia Rediviva
Columbia Rediviva
Columbia Rediviva was a privately owned ship under the command of John Kendrick, along with Captain Robert Gray, best known for going to the Pacific Northwest for the maritime fur trade. The "Rediviva" was added to her name upon a rebuilding in 1787...

; 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 13 miles (20.9 km) upstream. The farthest point reached was Grays Bay at the mouth of Grays River. Gray's discovery of the Columbia River was later used by the United States to support its claim to the Oregon Country
Oregon Country
The Oregon Country was a predominantly American term referring to a disputed ownership region of the Pacific Northwest of North America. The region was occupied by British and French Canadian fur traders from before 1810, and American settlers from the mid-1830s, with its coastal areas north from...

, which was also claimed by Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

, Great Britain
Kingdom of Great Britain
The former Kingdom of Great Britain, sometimes described as the 'United Kingdom of Great Britain', That the Two Kingdoms of Scotland and England, shall upon the 1st May next ensuing the date hereof, and forever after, be United into One Kingdom by the Name of GREAT BRITAIN. was a sovereign...

, Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

 and other nations.

In October 1792, Vancouver sent Lieutenant
Lieutenant
A lieutenant is a junior commissioned officer in many nations' armed forces. Typically, the rank of lieutenant in naval usage, while still a junior officer rank, is senior to the army rank...

 William Robert Broughton
William Robert Broughton
William Robert Broughton was a British naval officer in the late 18th century. As a Lieutenant in the Royal Navy, he commanded HMS Chatham as part of the Vancouver Expedition, a voyage of exploration through the Pacific Ocean led by Captain George Vancouver in the early 1790s.-With Vancouver:In...

, his second-in-command, up the river. Broughton got as far as the Sandy River
Sandy River (Oregon)
The Sandy River is a tributary of the Columbia River in northwestern Oregon in the United States. Measured by a United States Geological Survey gauge downstream of the Sandy's confluence with the Bull Run River, from the mouth, the river's average discharge is . The maximum daily recorded flow...

 at the western end of the Columbia River Gorge
Columbia River Gorge
The Columbia River Gorge is a canyon of the Columbia River in the Pacific Northwest of the United States. Up to deep, the canyon stretches for over as the river winds westward through the Cascade Range forming the boundary between the State of Washington to the north and Oregon to the south...

, about 100 miles (160.9 km) upstream, sighting and naming Mount Hood
Mount Hood
Mount Hood, called Wy'east by the Multnomah tribe, is a stratovolcano in the Cascade Volcanic Arc of northern Oregon. It was formed by a subduction zone and rests in the Pacific Northwest region of the United States...

. Broughton formally claimed the river, its drainage basin
Drainage basin
A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...

, and the nearby coast for Britain
Kingdom of Great Britain
The former Kingdom of Great Britain, sometimes described as the 'United Kingdom of Great Britain', That the Two Kingdoms of Scotland and England, shall upon the 1st May next ensuing the date hereof, and forever after, be United into One Kingdom by the Name of GREAT BRITAIN. was a sovereign...

. In contrast, Gray had not made any formal claims on behalf of the United States.

Because the Columbia was at the same latitude as the headwaters of the Missouri River
Missouri River
The Missouri River flows through the central United States, and is a tributary of the Mississippi River. It is the longest river in North America and drains the third largest area, though only the thirteenth largest by discharge. The Missouri's watershed encompasses most of the American Great...

, there was some speculation that Gray and Vancouver had discovered the long-sought Northwest Passage. A 1798 British map showed a dotted line connecting the Columbia with the Missouri. However, when the American explorers Meriwether Lewis
Meriwether Lewis
Meriwether Lewis was an American explorer, soldier, and public administrator, best known for his role as the leader of the Lewis and Clark Expedition also known as the Corps of Discovery, with William Clark...

 and William Clark charted the vast, unmapped lands of the American West in their overland expedition
Lewis and Clark Expedition
The Lewis and Clark Expedition, or ″Corps of Discovery Expedition" was the first transcontinental expedition to the Pacific Coast by the United States. Commissioned by President Thomas Jefferson and led by two Virginia-born veterans of Indian wars in the Ohio Valley, Meriwether Lewis and William...

 (1803–05), they found no passage between the rivers. After crossing the Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...

, Lewis and Clark built dugout canoes and paddled down the Snake River, reaching the Columbia near the present-day Tri-Cities, Washington
Tri-Cities, Washington
The Tri-Cities is a mid-sized metropolitan area in the southeastern part of the U.S. state of Washington, consisting of three neighboring cities: Kennewick, Pasco, and Richland. The cities are located at the confluence of the Yakima, Snake, and Columbia rivers in the semi-arid region of...

. They explored a few miles upriver, as far as Bateman Island
Bateman Island
Bateman Island is an island located on the Columbia River between the cities of Richland and Kennewick, Washington. It is approximately long and wide and is part of the city of Richland.-History:...

, before heading down the Columbia, concluding their journey at the river's mouth and establishing Fort Clatsop
Fort Clatsop
Fort Clatsop was the encampment of the Lewis and Clark Expedition in the Oregon Country near the mouth of the Columbia River during the winter of 1805-1806...

, a short-lived establishment that was occupied for less than three months.

Canadian
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

 explorer David Thompson
David Thompson (explorer)
David Thompson was an English-Canadian fur trader, surveyor, and map-maker, known to some native peoples as "Koo-Koo-Sint" or "the Stargazer"...

, of the North West Company
North West Company
The North West Company was a fur trading business headquartered in Montreal from 1779 to 1821. It competed with increasing success against the Hudson's Bay Company in what was to become Western Canada...

, spent the winter of 1807–08 at Kootenae House near the source of the Columbia at present-day Invermere, British Columbia
Invermere, British Columbia
Invermere is a community in eastern British Columbia, Canada, near the border of Alberta. With its growing permanent population of almost 4,000 , swelling to near 40,000 on summer weekends, it is the hub of the Columbia Valley between Golden, and Cranbrook...

. 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
John Jacob Astor
John Jacob Astor , born Johann Jakob Astor, was a German-American business magnate and investor who was the first prominent member of the Astor family and the first multi-millionaire in the United States...

's Pacific Fur Company
Pacific Fur Company
The Pacific Fur Company was founded June 23, 1810, in New York City. Half of the stock of the company was held by the American Fur Company, owned exclusively by John Jacob Astor, and Astor provided all of the capital for the enterprise. The other half of the stock was ascribed to working partners...

 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
Hudson's Bay Company
The Hudson's Bay Company , abbreviated HBC, or "The Bay" is the oldest commercial corporation in North America and one of the oldest in the world. A fur trading business for much of its existence, today Hudson's Bay Company owns and operates retail stores throughout Canada...

 (HBC) established Fort Vancouver
Fort Vancouver
Fort Vancouver was a 19th century fur trading outpost along the Columbia River that served as the headquarters of the Hudson's Bay Company in the company's Columbia District...

 on the bank of the Columbia, in what is now Vancouver, Washington
Vancouver, Washington
Vancouver is a city on the north bank of the Columbia River in the U.S. state of Washington. Incorporated in 1857, it is the fourth largest city in the state with a 2010 census population of 161,791 as of April 1, 2010...

, as the headquarters of the company's Columbia District
Columbia District
The Columbia District was a fur trading district in the Pacific Northwest region of British North America in the 19th century. It was explored by the North West Company between 1793 and 1811, and established as an operating fur district around 1810...

, which encompassed everything west of the Rocky Mountains. John McLoughlin
John McLoughlin
Dr. John McLoughlin, baptized Jean-Baptiste McLoughlin, was the Chief Factor of the Columbia Fur District of the Hudson's Bay Company at Fort Vancouver. He was later known as the "Father of Oregon" for his role in assisting the American cause in the Oregon Country in the Pacific Northwest...

, a physician, was appointed Chief Factor
Factor (agent)
A factor, from the Latin "he who does" , is a person who professionally acts as the representative of another individual or other legal entity, historically with his seat at a factory , notably in the following contexts:-Mercantile factor:In a relatively large company, there could be a hierarchy,...

 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 country in large numbers via the Oregon Trail
Oregon Trail
The Oregon Trail is a historic east-west wagon route that connected the Missouri River to valleys in Oregon and locations in between.After 1840 steam-powered riverboats and steamboats traversing up and down the Ohio, Mississippi and Missouri rivers sped settlement and development in the flat...

, despite the HBC's efforts to discourage American settlement in the region. For many the final leg of the journey involved travel down the lower Columbia River to Fort Vancouver. This part 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
Barlow Road
The Barlow Road is a historic road in what is now the U.S. state of Oregon. It was built in 1846 by Sam Barlow and Philip Foster, with authorization of the Provisional Legislature of Oregon, and served as the last overland segment of the Oregon Trail...

.

In the Treaty of 1818
Treaty of 1818
The Convention respecting fisheries, boundary and the restoration of slaves between the United States of America and the United Kingdom of Great Britain and Ireland, also known as the London Convention, Anglo-American Convention of 1818, Convention of 1818, or simply the Treaty of 1818, was a...

 the United States and Britain agreed that both nations were to enjoy equal rights in Oregon Country
Oregon Country
The Oregon Country was a predominantly American term referring to a disputed ownership region of the Pacific Northwest of North America. The region was occupied by British and French Canadian fur traders from before 1810, and American settlers from the mid-1830s, with its coastal areas north from...

 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 to 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
Oregon boundary dispute
The Oregon boundary dispute, or the Oregon Question, arose as a result of competing British and American claims to the Pacific Northwest of North America in the first half of the 19th century. Both the United Kingdom and the United States had territorial and commercial aspirations in the region...

. While some British interests, especially the Hudson's Bay Company, fought for a boundary along the Columbia River, the Oregon Treaty
Oregon Treaty
The Oregon Treaty is a treaty between the United Kingdom and the United States that was signed on June 15, 1846, in Washington, D.C. The treaty brought an end to the Oregon boundary dispute by settling competing American and British claims to the Oregon Country, which had been jointly occupied by...

 of 1846 set the boundary at the 49th parallel. The Columbia River did become the border between the U.S. territories of Oregon
Oregon Territory
The Territory of Oregon was an organized incorporated territory of the United States that existed from August 14, 1848, until February 14, 1859, when the southwestern portion of the territory was admitted to the Union as the State of Oregon. Originally claimed by several countries , the region was...

 and Washington
Washington Territory
The Territory of Washington was an organized incorporated territory of the United States that existed from February 8, 1853, until November 11, 1889, when the final extent of the territory was admitted to the Union as the State of 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
Inland Empire (Pacific Northwest)
thumb|The Inland Empire regionThe Inland Northwest, or Inland Empire, is a region in the Pacific Northwest centered on Spokane, Washington, including the surrounding Columbia River basin and all of North Idaho....

 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
Electricity
Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...

, irrigation
Irrigation
Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...

, navigability
Navigability
A body of water, such as a river, canal or lake, is navigable if it is deep, wide and slow enough for a vessel to pass. Preferably there are few obstructions such as rocks or trees to avoid. Bridges must have sufficient clearance. High water speed may make a channel unnavigable. Waters may be...

 and other benefits to the region.

Navigation

American captain Robert Gray and British captain George Vancouver
George Vancouver
Captain George Vancouver RN was an English officer of the British Royal Navy, best known for his 1791-95 expedition, which explored and charted North America's northwestern Pacific Coast regions, including the coasts of contemporary Alaska, British Columbia, Washington and Oregon...

, who explored the river in 1792, proved that it was possible to cross the Columbia Bar
Columbia Bar
The Columbia Bar is a system of bars and shoals at the mouth of the Columbia River spanning the US states of Oregon and Washington. The bar is about wide and long....

. 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
Beaver (steamship)
Beaver was the first steamship to operate in the Pacific Northwest of North America. She made remote parts of the west coast of Canada accessible for maritime fur trading and was chartered by the Royal Navy for surveying the coastline of British Columbia....

in 1836 and followed by American vessels in 1850, contributed to the rapid settlement and economic development of the region. Steamboats operated in several distinct stretches of the river: on its lower reaches, from the Pacific Ocean to Cascades Rapids
Cascades Rapids
The Cascades Rapids were an area of rapids along North America's Columbia River, between the U.S. states of Washington and Oregon. Through a stretch approximately wide, the river dropped about in .-Boat portage:Boat travelers were forced to either portage boats and supplies or pull boats up with...

; from the Cascades to Celilo Falls; from Celilo to the confluence with the Snake River; on the Wenatchee Reach
Steamboats of Columbia River, Wenatchee Reach
Steamboats operated on the Wenatchee Reach of the Columbia River from the late 1880s to 1915. The main base of operations was Wenatchee, Washington, located at the confluence of the Wenatchee and Columbia Rivers, from the mouth of the river. Operations were mainly between Wenatchee and Bridgeport...

 of eastern Washington; on British Columbia's Arrow Lakes
Steamboats of the Arrow Lakes
The era of steamboats on the Arrow Lakes and adjoining reaches of the Columbia River is long-gone but was an important part of the history of the West Kootenay and Columbia Country regions of British Columbia. The Arrow Lakes are formed by the Columbia River in southeastern British Columbia...

; and on tributaries like the Willamette
Steamboats of the Willamette River
The Willamette River flows northwards down the Willamette Valley until it meets the Columbia River at a point 101 miles from the Pacific Ocean, in the U.S. state of Oregon.-Route and early operations:...

, the Snake and Kootenay Lake
Kootenay Lake
Kootenay Lake is a lake located in British Columbia, Canada and is part of theKootenay River. The lake has been raised by the Corra Linn Dam and has a dike system at the southern end, which, along with industry in the 1950s-70s, has changed the ecosystem in and around the water...

. The boats, initially powered by burning wood, carried passengers and freight throughout the region for many years. Early 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
Oregon Railroad and Navigation Company
The Oregon Railroad and Navigation Company was a railroad that operated a rail network of of track running east from Portland, Oregon, United States to northeastern Oregon, northeastern Washington, and northern Idaho...

 and the Shaver Transportation Company
Shaver Transportation Company
The Shaver Transportation Company is an inland water freight transportation company based in Portland, Oregon, United States. The company was founded in 1880, and played a major role in the development of freight transport in the Portland area and along the Columbia., Harry L...

 began to supplement steamboat operations as the major transportation links along the river.

Opening the passage to Lewiston

As early as 1881, industrialists proposed altering the natural channel of the Columbia to improve navigation. Changes to the river over the years have included the construction of jetties
Jetty
A jetty is any of a variety of structures used in river, dock, and maritime works that are generally carried out in pairs from river banks, or in continuation of river channels at their outlets into deep water; or out into docks, and outside their entrances; or for forming basins along the...

 at the river's mouth, dredging, and the construction of canal
Canal
Canals are man-made channels for water. There are two types of canal:#Waterways: navigable transportation canals used for carrying ships and boats shipping goods and conveying people, further subdivided into two kinds:...

s and navigation locks
Lock (water transport)
A lock is a device for raising and lowering boats between stretches of water of different levels on river and canal waterways. The distinguishing feature of a lock is a fixed chamber in which the water level can be varied; whereas in a caisson lock, a boat lift, or on a canal inclined plane, it is...

. Today, ocean freighters can travel upriver as far as Portland and Vancouver, and barges can reach as far inland as Lewiston, Idaho
Lewiston, Idaho
Lewiston is a city in and also the county seat of Nez Perce County in the Pacific Northwest state of Idaho. It is the second-largest city in the northern Idaho region, behind Coeur d'Alene and ninth-largest in the state. Lewiston is the principal city of the Lewiston, ID - Clarkston, WA...

.

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 17 feet (5.2 m) to 25 feet (7.6 m). The Columbian
The Columbian
The Columbian is a daily newspaper for Vancouver, Washington and Clark County in Washington State in the United States. The paper was published for its first decade as a four page daily that was meant as a counterweight to the local Republican newspaper The Independent. Printer Tom Carolan began...

called for the channel to be deepened to 40 feet (12.2 m) as early as 1905, but that depth was not attained until 1976.

Cascade Locks and Canal
Cascade Locks and Canal
The Cascade Locks and Canal was a navigation project on the Columbia River between the U.S. states of Oregon and Washington, completed in 1896. It allowed the steamboats of the Columbia River to bypass the Cascades Rapids, and thereby opened a passage from the lower parts of the river as far as The...

 were first constructed in 1896 around the Cascades Rapids, enabling boats to travel safely through the Columbia River Gorge. The Celilo Canal
Celilo Canal
Celilo Canal was a canal connecting two points of the Columbia River between the states of Oregon and Washington, U.S. just east of The Dalles....

, 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
1980 eruption of Mount St. Helens
The 1980 eruption of Mount St. Helens, a stratovolcano located in Washington state, in the United States, was a major volcanic eruption. The eruption was the only significant one to occur in the contiguous 48 U.S. states since the 1915 eruption of Lassen Peak in California...

 caused mudslides in the area, which reduced the Columbia's depth by 25 feet (7.6 m) for a 4 miles (6.4 km) stretch, disrupting Portland's economy.

Deeper shipping channel

Efforts to maintain and improve the navigation channel have continued to the present day. In 1990, a new round of studies examined the possibility of further dredging on the lower Columbia. The plans were controversial from the start because of economic and environmental concerns.

In 1999, Congress authorized deepening the channel between Portland and Astoria from 40 to 43 ft (12.2 to 13.1 m), which will make it possible for large container and grain ships to reach Portland and Vancouver. However, the project has met opposition because of 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
United States Court of Appeals for the Ninth Circuit
The United States Court of Appeals for the Ninth Circuit is a U.S. federal court with appellate jurisdiction over the district courts in the following districts:* District of Alaska* District of Arizona...

 in August 2006. The project includes measures to mitigate environmental damage; for instance, the U.S. Army Corps of Engineers
United States Army Corps of Engineers
The United States Army Corps of Engineers is a federal agency and a major Army command made up of some 38,000 civilian and military personnel, making it the world's largest public engineering, design and construction management agency...

 must restore 12 times the area of wetland damaged by the project. In early 2006, the Corps spilled 50 gallons (189.3 l) 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.

Dams: harnessing the river


In 1902, the United States Bureau of Reclamation
United States Bureau of Reclamation
The United States Bureau of Reclamation , and formerly the United States Reclamation Service , is an agency under the U.S...

 was established to aid in the economic development
Economic development
Economic development generally refers to the sustained, concerted actions of policymakers and communities that promote the standard of living and economic health of a specific area...

 of arid western states
Western United States
.The Western United States, commonly referred to as the American West or simply "the West," traditionally refers to the region comprising the westernmost states of the United States. Because the U.S. expanded westward after its founding, the meaning of the West has evolved over time...

. One of its major undertakings was building Grand Coulee Dam
Grand Coulee Dam
Grand Coulee Dam is a gravity dam on the Columbia River in the U.S. state of Washington built to produce hydroelectric power and provide irrigation. It was constructed between 1933 and 1942, originally with two power plants. A third power station was completed in 1974 to increase its energy...

 to provide irrigation for the 600 thousand acres (2,428.1 km²) of the Columbia Basin Project
Columbia Basin Project
The Columbia Basin Project in Central Washington, USA, is the irrigation network that the Grand Coulee Dam makes possible. It is the largest water reclamation project in the United States, supplying irrigation water to over of the large project area, all of which was originally intended to be...

 in central Washington. With the onset of World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

, the focus of dam construction shifted to production of hydroelectricity
Hydroelectricity
Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy...

. Irrigation efforts resumed after the war.

River development occurred within the structure of the 1909 International Boundary Waters Treaty
International Boundary Waters Treaty
The Boundary Waters Treaty is the 1909 treaty between the United States and Canada providing mechanisms for resolving any dispute over any waters bordering the two countries...

 between the U.S. and Canada. The United States Congress
United States Congress
The United States Congress is the bicameral legislature of the federal government of the United States, consisting of the Senate and the House of Representatives. The Congress meets in the United States Capitol in Washington, D.C....

 passed the Rivers and Harbors Act of 1925, which directed the Army Corps of Engineers and the Federal Power Commission
Federal Power Commission
The Federal Power Commission was an independent commission of the United States government, originally organized on June 23, 1930, with five members nominated by the president and confirmed by the Senate...

 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
Northwestern United States
The Northwestern United States comprise the northwestern states up to the western Great Plains regions of the United States, and consistently include the states of Oregon, Washington, Idaho, Montana, Wyoming, to which part of southeast Alaska is also sometimes included...

 generally favored private development of hydroelectric dams along the Columbia. But the overwhelming victories of gubernatorial candidate George W. Joseph
George W. Joseph
George W. P. Joseph was an attorney and Republican politician in the U.S. state of Oregon. A native of California, his family relocated to Oregon when he was young. There he would practice law and serve in the Oregon State Senate....

 in the 1930 Oregon Republican Party
Oregon Republican Party
The Oregon Republican Party is the state affiliate of the United States Republican Party in Oregon, headquartered in Lake Oswego. The first state party convention was held in Salem on April 21, 1859, and its first nominee for Congress, Portland attorney David Logan...

 primary, and later his law partner Julius Meier
Julius Meier
Julius L. Meier was an American businessman and politician in the state of Oregon. The son of the Meier & Frank department store founder, he would become a lawyer before entering the family business in Portland...

, were understood to demonstrate strong public support for public ownership of dams. In 1933, President Franklin D. Roosevelt
Franklin D. Roosevelt
Franklin Delano Roosevelt , also known by his initials, FDR, was the 32nd President of the United States and a central figure in world events during the mid-20th century, leading the United States during a time of worldwide economic crisis and world war...

 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
Clarence Dill
Clarence Cleveland Dill was an American politician from the state of Washington. He was a Democrat.Dill was born in Knox County, Ohio. He attended Ohio Wesleyan University, where he was a member of Phi Kappa Psi....

, and Oregon Congressman Charles Martin, among others.

In 1948 floods swept through the Columbia watershed, destroying Vanport
Vanport, Oregon
Vanport City was a hastily constructed city of public housing located in Multnomah County, Oregon, United States, between the contemporary Portland city boundary and the Columbia River. It is currently the site of Delta Park and the Portland International Raceway.It was constructed in 1943 to house...

, then the second largest city in Oregon, and impacting cities as far north as Trail, British Columbia
Trail, British Columbia
Trail is a city in the West Kootenay region of the Interior of British Columbia, Canada.-Geography:Trail has an area of . The city is located on both banks of the Columbia River, approximately 10 km north of the United States border. This section of the Columbia River valley is located between the...

. The flooding prompted the United States Congress
United States Congress
The United States Congress is the bicameral legislature of the federal government of the United States, consisting of the Senate and the House of Representatives. The Congress meets in the United States Capitol in Washington, D.C....

 to pass the Flood Control Act of 1950
Flood Control Act of 1950
The Flood Control Act of 1950 was a law passed by the United States Congress authorizing flood control projects in Montana, Wyoming, Utah, Nevada, Idaho, Oregon, and Washington....

, authorizing the federal development of additional dams and other flood control
Flood control
In communications, flood control is a feature of many communication protocols designed to prevent overwhelming of a destination receiver. Such controls can be implemented either in software or in hardware, and will often request that the message be resent after the receiver has finished...

 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
Public utility district
In the United States, a public utility district is a special-purpose district or other governmental jurisdiction that provides public utilities to the residents of that district.PUDs are created by a local government body, such as a city, county, or...

 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
Columbia River Treaty
The Columbia River Treaty is an agreement between Canada and the United States of America on the development and operation of dams in the upper Columbia River basin for power and flood control benefits in both countries. For more information about the Columbia River Treaty, visit Columbia Basin...

, 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
Duncan River
The Duncan River is a long river in the Canadian province of British Columbia. Its drainage basin is in area. It is part of the Columbia River basin, being tributary via Kootenay Lake to the Kootenay River, which is a tributary of the Columbia 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
Lock (water transport)
A lock is a device for raising and lowering boats between stretches of water of different levels on river and canal waterways. The distinguishing feature of a lock is a fixed chamber in which the water level can be varied; whereas in a caisson lock, a boat lift, or on a canal inclined plane, it is...

 to allow ship and barge passage from the ocean as far as Lewiston, Idaho
Lewiston, Idaho
Lewiston is a city in and also the county seat of Nez Perce County in the Pacific Northwest state of Idaho. It is the second-largest city in the northern Idaho region, behind Coeur d'Alene and ninth-largest in the state. Lewiston is the principal city of the Lewiston, ID - Clarkston, WA...

. 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
Land reclamation
Land reclamation, usually known as reclamation, is the process to create new land from sea or riverbeds. The land reclaimed is known as reclamation ground or landfill.- Habitation :...

 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
United States Army Corps of Engineers
The United States Army Corps of Engineers is a federal agency and a major Army command made up of some 38,000 civilian and military personnel, making it the world's largest public engineering, design and construction management agency...

 and some by the Bureau of Reclamation), while the smaller dams are operated by public utility district
Public utility district
In the United States, a public utility district is a special-purpose district or other governmental jurisdiction that provides public utilities to the residents of that district.PUDs are created by a local government body, such as a city, county, or...

s, and private power companies. The federally operated system is known as the Federal Columbia River Power System
Federal Columbia River Power System
The Federal Columbia River Power System is a series of multi-purpose, hydroelectric facilities constructed and operated by the United States Army Corps of Engineers and the Bureau of Reclamation in the Pacific Northwest, and a transmission system built and operated by the Bonneville Power...

, 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
Salmon
Salmon is the common name for several species of fish in the family Salmonidae. Several other fish in the same family are called trout; the difference is often said to be that salmon migrate and trout are resident, but this distinction does not strictly hold true...

-producing river systems in the world. Previously active fishing sites, most notably Celilo Falls
Celilo Falls
Celilo Falls was a tribal fishing area on the Columbia River, just east of the Cascade Mountains, on what is today the border between the U.S. states of Oregon and Washington...

 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 ladder
Fish ladder
A fish ladder, also known as a fishway, fish pass or fish steps, is a structure on or around artificial barriers to facilitate diadromous fishes' natural migration. Most fishways enable fish to pass around the barriers by swimming and leaping up a series of relatively low steps into the waters on...

s have been installed at some dam sites to help the fish journey to spawning waters. Chief Joseph Dam
Chief Joseph Dam
The Chief Joseph Dam is a concrete gravity dam on the Columbia River, upriver from Bridgeport, Washington, USA. The dam was authorized as Foster Creek Dam and Powerhouse for power generation and irrigation by the River and Harbor Act of 1946...

 has no fish ladders and completely blocks fish migration to the upper half of the Columbia River system.

Irrigation

The Bureau of Reclamation's Columbia Basin Project
Columbia Basin Project
The Columbia Basin Project in Central Washington, USA, is the irrigation network that the Grand Coulee Dam makes possible. It is the largest water reclamation project in the United States, supplying irrigation water to over of the large project area, all of which was originally intended to be...

 focused on the generally dry region of central Washington known as the Columbia Basin, which features rich loess
Loess
Loess is an aeolian sediment formed by the accumulation of wind-blown silt, typically in the 20–50 micrometre size range, twenty percent or less clay and the balance equal parts sand and silt that are loosely cemented by calcium carbonate...

 soil. Several groups developed competing proposals, and in 1933, President Franklin D. Roosevelt
Franklin D. Roosevelt
Franklin Delano Roosevelt , also known by his initials, FDR, was the 32nd President of the United States and a central figure in world events during the mid-20th century, leading the United States during a time of worldwide economic crisis and world war...

 authorized the Columbia Basin Project. The Grand Coulee Dam
Grand Coulee Dam
Grand Coulee Dam is a gravity dam on the Columbia River in the U.S. state of Washington built to produce hydroelectric power and provide irrigation. It was constructed between 1933 and 1942, originally with two power plants. A third power station was completed in 1974 to increase its energy...

 was the project's central component; upon completion, it pumped water up from the Columbia to fill the formerly dry Grand Coulee
Grand Coulee
The Grand Coulee is an ancient river bed in the U.S. state of Washington. This National Natural Landmark stretches for about sixty miles southwest from Grand Coulee Dam to Soap Lake, being bisected by Dry Falls into the Upper and Lower Grand Coulee....

, forming Banks Lake
Banks Lake
Banks Lake is a long reservoir in central Washington in the United States.Part of the Columbia Basin Project, Banks Lake occupies the northern portion of the Grand Coulee, a formerly dry coulee near the Columbia River, formed by the Missoula Floods during the Pleistocene epoch. Grand Coulee Dam,...

. By 1935, the intended height of the dam was increased from a range between 200 and 300 ft (61 and 91.4 m) to 500 feet (152.4 m), a height that would extend the lake impounded by the dam all the way to the Canadian border; the project had grown from a local New Deal
New Deal
The New Deal was a series of economic programs implemented in the United States between 1933 and 1936. They were passed by the U.S. Congress during the first term of President Franklin D. Roosevelt. The programs were Roosevelt's responses to the Great Depression, and focused on what historians call...

 relief measure to a major national project.

The project's initial purpose was irrigation
Irrigation
Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...

, but the onset of World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

 created a high demand for electricity, mainly for aluminum production and for the development of nuclear weapon
Nuclear weapon
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission bomb test released the same amount...

s at the Hanford Site
Hanford Site
The Hanford Site is a mostly decommissioned nuclear production complex on the Columbia River in the U.S. state of Washington, operated by the United States federal government. The site has been known by many names, including Hanford Works, Hanford Engineer Works or HEW, Hanford Nuclear Reservation...

. Irrigation began in 1951. The project provides water to more than 670 thousand acres (2,711.4 km²) of fertile but arid land in central Washington, transforming the region into a major agricultural center. Important crops include orchard fruit
Orchard
An orchard is an intentional planting of trees or shrubs that is maintained for food production. Orchards comprise fruit or nut-producing trees which are grown for commercial production. Orchards are also sometimes a feature of large gardens, where they serve an aesthetic as well as a productive...

, potato
Potato
The potato is a starchy, tuberous crop from the perennial Solanum tuberosum of the Solanaceae family . The word potato may refer to the plant itself as well as the edible tuber. In the region of the Andes, there are some other closely related cultivated potato species...

es, alfalfa
Alfalfa
Alfalfa is a flowering plant in the pea family Fabaceae cultivated as an important forage crop in the US, Canada, Argentina, France, Australia, the Middle East, South Africa, and many other countries. It is known as lucerne in the UK, France, Australia, South Africa and New Zealand, and known as...

, mint
Mentha
Mentha is a genus of flowering plants in the family Lamiaceae . The species are not clearly distinct and estimates of the number of species varies from 13 to 18. Hybridization between some of the species occurs naturally...

, bean
Bean
Bean is a common name for large plant seeds of several genera of the family Fabaceae used for human food or animal feed....

s, beet
Beet
The beet is a plant in the Chenopodiaceae family which is now included in Amaranthaceae family. It is best known in its numerous cultivated varieties, the most well known of which is the purple root vegetable known as the beetroot or garden beet...

s, and wine
Wine
Wine is an alcoholic beverage, made of fermented fruit juice, usually from grapes. The natural chemical balance of grapes lets them ferment without the addition of sugars, acids, enzymes, or other nutrients. Grape wine is produced by fermenting crushed grapes using various types of yeast. Yeast...

 grape
Grape
A grape is a non-climacteric fruit, specifically a berry, that grows on the perennial and deciduous woody vines of the genus Vitis. Grapes can be eaten raw or they can be used for making jam, juice, jelly, vinegar, wine, grape seed extracts, raisins, molasses and grape seed oil. Grapes are also...

s.

Since 1750, the Columbia has experienced six multi-year droughts. The longest, lasting 12 years in the mid-19th century, 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 1992–1993, 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 a hundred 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.

Hydroelectricity

The Columbia's heavy flow and extreme elevation drop over a short distance, 2.16 ft/mi, give it tremendous capacity for hydroelectricity
Hydroelectricity
Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy...

 generation. In comparison, the Mississippi drops less than 0.65 ft/mi. The Columbia alone possesses one-third of the United States's hydroelectric potential.

The largest of the 150 hydroelectric projects, the Grand Coulee Dam
Grand Coulee Dam
Grand Coulee Dam is a gravity dam on the Columbia River in the U.S. state of Washington built to produce hydroelectric power and provide irrigation. It was constructed between 1933 and 1942, originally with two power plants. A third power station was completed in 1974 to increase its energy...

 and the Chief Joseph Dam
Chief Joseph Dam
The Chief Joseph Dam is a concrete gravity dam on the Columbia River, upriver from Bridgeport, Washington, USA. The dam was authorized as Foster Creek Dam and Powerhouse for power generation and irrigation by the River and Harbor Act of 1946...

, are also the largest in the United States and among the largest in the world.

Inexpensive hydropower supported the emergence of an extensive aluminum industry, which draws tremendous amounts of power. Until 2000, the Northwestern United States
Northwestern United States
The Northwestern United States comprise the northwestern states up to the western Great Plains regions of the United States, and consistently include the states of Oregon, Washington, Idaho, Montana, Wyoming, to which part of southeast Alaska is also sometimes included...

 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 21st century, 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
Google
Google Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...

 have begun to move server farm
Server farm
A server farm or server cluster is a collection of computer servers usually maintained by an enterprise to accomplish server needs far beyond the capability of one machine. Server farms often have backup servers, which can take over the function of primary servers in the event of a primary server...

 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
Bonneville Power Administration
The Bonneville Power Administration is an American federal agency based in the Pacific Northwest. BPA was created by an act of Congress in 1937 to market electric power from the Bonneville Dam located on the Columbia River and to construct facilities necessary to transmit that power...

 (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
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...

 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
Snake River
The Snake is a major river of the greater Pacific Northwest in the United States. At long, it is the largest tributary of the Columbia River, the largest North American river that empties into the Pacific Ocean...

, the largest tributary of the Columbia.

In 1941, the BPA hired Oklahoma
Oklahoma
Oklahoma is a state located in the South Central region of the United States of America. With an estimated 3,751,351 residents as of the 2010 census and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...

 folksinger Woody Guthrie
Woody Guthrie
Woodrow Wilson "Woody" Guthrie is best known as an American singer-songwriter and folk musician, whose musical legacy includes hundreds of political, traditional and children's songs, ballads and improvised works. He frequently performed with the slogan This Machine Kills Fascists displayed on his...

 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.

Fish migration

The Columbia supports several species of anadromous fish that migrate between the Pacific Ocean and fresh water tributaries of the river. Coho
Coho salmon
The Coho salmon, Oncorhynchus kisutch, is a species of anadromous fish in the salmon family. Coho salmon are also known as silver salmon or "silvers". It is the state animal of Chiba, Japan.-Description:...

 and Chinook
Chinook salmon
The Chinook salmon, Oncorhynchus tshawytscha, is the largest species in the pacific salmon family. Other commonly used names for the species include King salmon, Quinnat salmon, Spring salmon and Tyee salmon...

 (also known as "king") salmon, and steelhead
Rainbow trout
The rainbow trout is a species of salmonid native to tributaries of the Pacific Ocean in Asia and North America. The steelhead is a sea run rainbow trout usually returning to freshwater to spawn after 2 to 3 years at sea. In other words, rainbow trout and steelhead trout are the same species....

, all of the genus Oncorhynchus
Oncorhynchus
Oncorhynchus is a genus of fish in the family Salmonidae; it contains the Pacific salmons and Pacific trouts. The name of the genus is derived from the Greek onkos and rynchos , in reference to the hooked jaws of males in the mating season .-Range:Salmon and trout with ranges generally in waters...

, are ocean fish that migrate up the rivers at the end of their life cycles to spawn. White sturgeon
White sturgeon
The white sturgeon , also known as the Pacific sturgeon, Oregon sturgeon, Columbia sturgeon, Sacramento sturgeon, and California white sturgeon, is a sturgeon which lives along the west coast of North America from the Aleutian Islands to Central...

, which take 15 to 25 years to mature, typically migrate between the ocean and the upstream habitat several times during their lives.

Salmon populations declined dramatically after the establishment of canneries in 1867. By 1908, there was widespread concern about the decline of salmon and sturgeon. In that year, the people of Oregon passed two laws under their newly instituted program of Citizens' Initiatives limiting fishing on the Columbia and other rivers. Then in 1948, another initiative banned the use of seine nets (devices invented by Native Americans, and refined by later settlers) altogether.

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 ladder
Fish ladder
A fish ladder, also known as a fishway, fish pass or fish steps, is a structure on or around artificial barriers to facilitate diadromous fishes' natural migration. Most fishways enable fish to pass around the barriers by swimming and leaping up a series of relatively low steps into the waters on...

s, 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
Chief Joseph Dam
The Chief Joseph Dam is a concrete gravity dam on the Columbia River, upriver from Bridgeport, Washington, USA. The dam was authorized as Foster Creek Dam and Powerhouse for power generation and irrigation by the River and Harbor Act of 1946...

 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.

Not all fish have suffered from the modifications to the river; the northern pikeminnow (formerly known as the squawfish) thrives in the warmer, slower water created by the dams. Research in the mid-1980s found that juvenile salmon were suffering substantially from the predatory pikeminnow, and in 1990, in the interest of protecting salmon, a "bounty" program was established to reward anglers for catching pikeminnow.

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
Coho salmon
The Coho salmon, Oncorhynchus kisutch, is a species of anadromous fish in the salmon family. Coho salmon are also known as silver salmon or "silvers". It is the state animal of Chiba, Japan.-Description:...

 far exceeded expectations, which was attributed in part to the fishing ban.

Also in 1994, United States Secretary of the Interior
United States Secretary of the Interior
The United States Secretary of the Interior is the head of the United States Department of the Interior.The US Department of the Interior should not be confused with the concept of Ministries of the Interior as used in other countries...

 Bruce Babbitt
Bruce Babbitt
Bruce Edward Babbitt , a Democrat, served as United States Secretary of the Interior and as the 16th governor of Arizona, from 1978 to 1987.-Biography:...

 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
Snake River
The Snake is a major river of the greater Pacific Northwest in the United States. At long, it is the largest tributary of the Columbia River, the largest North American river that empties into the Pacific Ocean...

 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
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....

's Salmon
Salmon River (Idaho)
The Salmon River is located in Idaho in the northwestern United States. The Salmon is also known as The River of No Return. It flows for through central Idaho, draining and dropping more than between its headwaters, near Galena Summit above the Sawtooth Valley in the Sawtooth National...

 and Clearwater
Clearwater River (Idaho)
The Clearwater River is a river in north central Idaho, which flows westward from the Bitterroot Mountains along the Idaho-Montana border, and joins the Snake River at Lewiston. In October 1805, the Lewis and Clark Expedition descended the Clearwater River in dugout canoes, putting in at "Canoe...

 rivers. Historically, the Snake produced over 1.5 million spring and summer Chinook Salmon
Chinook salmon
The Chinook salmon, Oncorhynchus tshawytscha, is the largest species in the pacific salmon family. Other commonly used names for the species include King salmon, Quinnat salmon, Spring salmon and Tyee salmon...

, a number that has dwindled to several thousand in recent years. Idaho Power Company
Idaho Power Company
Idaho Power Company is a regulated electrical power utility. Its business involves the purchase, sale, generation, transmission and distribution of electricity in eastern Oregon and southern Idaho. It is a subsidiary of IDACORP, Inc...

's Hells Canyon
Hells Canyon
Hells Canyon is a wide canyon located along the border of eastern Oregon and western Idaho in the United States. It is North America's deepest river gorge at and part of the Hells Canyon National Recreation Area....

 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
Bull Run Hydroelectric Project
The Bull Run Hydroelectric Project was a Portland General Electric development in the Sandy River basin in the U.S. state of Oregon. Originally built between 1908 and 1912 near the town of Bull Run, it supplied hydroelectric power for the Portland area for nearly a century, until it was removed in...

 on the Sandy River
Sandy River (Oregon)
The Sandy River is a tributary of the Columbia River in northwestern Oregon in the United States. Measured by a United States Geological Survey gauge downstream of the Sandy's confluence with the Bull Run River, from the mouth, the river's average discharge is . The maximum daily recorded flow...

 was the first dam removal in the system. There are plans to remove the Condit Dam
Condit Hydroelectric Project
Condit Hydroelectric Project was a development on the White Salmon River in the U.S. state of Washington. It was completed in 1913 to provide electrical power for local industry and is listed in the National Register of Historic Places as an engineering and architecture landmark.PacifiCorp...

 on Washington's White Salmon River
White Salmon River
The White Salmon River is a river flowing into the Columbia River Gorge, originating on the slopes of Mount Adams. The lower portion of the river is in the Columbia River Gorge National Scenic Area and some of the upper sections are part of the National Wild and Scenic Rivers system...

, and the Milltown Dam
Milltown Dam
The Milltown Reservoir Sediments Superfund Site is part of the largest Superfund complex in the western United States. Situated in the Clark Fork River Basin, the complex stretches from the Warm Spring Ponds area near Butte, MT to the Milltown Dam site east of Missoula, MT...

 on the Clark Fork
Clark Fork (river)
The Clark Fork is a river in the U.S. states of Montana and Idaho, approximately long. The largest river by volume in Montana, it drains an extensive region of the Rocky Mountains in western Montana and northern Idaho in the watershed of the Columbia River, flowing northwest through a long...

 in Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...

.

Pollution

In southeastern Washington, a 50 miles (80.5 km) stretch of the river passes through the Hanford Site
Hanford Site
The Hanford Site is a mostly decommissioned nuclear production complex on the Columbia River in the U.S. state of Washington, operated by the United States federal government. The site has been known by many names, including Hanford Works, Hanford Engineer Works or HEW, Hanford Nuclear Reservation...

, established in 1943 as part of the Manhattan Project
Manhattan Project
The Manhattan Project was a research and development program, led by the United States with participation from the United Kingdom and Canada, that produced the first atomic bomb during World War II. From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the US Army...

. The site served as a plutonium
Plutonium
Plutonium is a transuranic radioactive chemical element with the chemical symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, forming a dull coating when oxidized. The element normally exhibits six allotropes and four oxidation...

 production complex, with nine nuclear reactor
Nuclear reactor
A nuclear reactor is a device to initiate and control a sustained nuclear chain reaction. Most commonly they are used for generating electricity and for the propulsion of ships. Usually heat from nuclear fission is passed to a working fluid , which runs through turbines that power either ship's...

s and related facilities located on the banks of the river. From 1944 to 1971, pump systems drew cooling water from the river and, after treating this water for use by the reactors, returned it to the river. Before being released back into the river, the used water was held in large tanks known as retention basins for up to six hours. Longer-lived isotope
Isotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...

s were not affected by this retention, and several terabecquerels
Becquerel
The becquerel is the SI-derived unit of radioactivity. One Bq is defined as the activity of a quantity of radioactive material in which one nucleus decays per second. The Bq unit is therefore equivalent to an inverse second, s−1...

 entered the river every day. By 1957, the eight plutonium production reactors at Hanford dumped a daily average of 50,000 curie
Curie
The curie is a unit of radioactivity, defined asThis is roughly the activity of 1 gram of the radium isotope 226Ra, a substance studied by the pioneers of radiology, Marie and Pierre Curie, for whom the unit was named. In addition to the curie, activity can be measured using an SI derived unit,...

s of radioactive material into the Columbia. These releases were kept secret by the federal government until the release of declassified documents in the late 1980s. Radiation was measured downstream as far west as the Washington and Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...

 coasts.

The nuclear reactors were decommissioned at the end of the Cold War
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...

, and the Hanford site is now the focus of the world's largest environmental cleanup, managed by the Department of Energy
United States Department of Energy
The United States Department of Energy is a Cabinet-level department of the United States government concerned with the United States' policies regarding energy and safety in handling nuclear material...

 under the oversight of the Washington Department of Ecology
Washington Department of Ecology
The Washington Department of Ecology, or simply, Ecology, is an environmental regulatory agency for the State of Washington. The department administers laws and regulations pertaining to the areas of water quality, water rights and water resources, shoreline management, toxics clean-up, nuclear...

 and the Environmental Protection Agency
United States Environmental Protection Agency
The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...

. 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. , 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
Polychlorinated biphenyl
Polychlorinated biphenyls are a class of organic compounds with 2 to 10 chlorine atoms attached to biphenyl, which is a molecule composed of two benzene rings. The chemical formula for PCBs is C12H10-xClx...

 (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
Superfund
Superfund is the common name for the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 , a United States federal law designed to clean up sites contaminated with hazardous substances...

 projects at Portland Harbor, Hanford, and Lake Roosevelt
Franklin D. Roosevelt Lake
Franklin D. Roosevelt Lake is the reservoir created in 1941 by the impoundment of the Columbia River by the Grand Coulee Dam in Washington state. It is named for Franklin D. Roosevelt, who was President during the construction of the dam...

.

Timber industry activity further contaminates river water, notably in the increased sediment runoff that results from clearcuts
Clearcutting
Clearcutting, or clearfelling, is a controversial forestry/logging practice in which most or all trees in an area are uniformly cut down. Clearcutting, along with shelterwood and seed tree harvests, is used by foresters to create certain types of forest ecosystems and to promote select species that...

. The Northwest Forest Plan
Northwest Forest Plan
The Northwest Forest Plan is a series of federal policies and guidelines governing land use on federal lands in the Pacific Northwest region of the United States. It covers areas ranging from Northern California to western Washington...

, 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.

Watershed

Most of the Columbia's drainage basin
Drainage basin
A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...

 (which, at 258000 mi2, 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
Grand Teton National Park
Grand Teton National Park is a United States National Park located in northwestern Wyoming, U.S. The Park consists of approximately and includes the major peaks of the long Teton Range as well as most of the northern sections of the valley known as Jackson Hole. Only south of Yellowstone...

 lies in the watershed, as well as parts of Yellowstone National Park
Yellowstone National Park
Yellowstone National Park, established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872, is a national park located primarily in the U.S. state of Wyoming, although it also extends into Montana and Idaho...

, Glacier National Park, Mount Rainier National Park
Mount Rainier National Park
Mount Rainier National Park is a United States National Park located in southeast Pierce County and northeast Lewis County in Washington state. It was one of the US's earliest National Parks, having been established on March 2, 1899 as the fifth national park in the United States. The park contains...

, and North Cascades National Park
North Cascades National Park
North Cascades National Park is a U.S. National Park located in the state of Washington. The park is the largest of the three National Park Service units that comprise the North Cascades National Park Service Complex. Several national wilderness areas and British Columbia parkland adjoin the...

. Canadian National Parks in the watershed include Kootenay National Park
Kootenay National Park
Kootenay National Park is located in southeastern British Columbia Canada covering in the Canadian Rockies and forms part of a World Heritage Site. The park ranges in elevation from at the south-west park entrance to at Deltaform Mountain...

, Yoho National Park
Yoho National Park
Yoho National Park is located in the Canadian Rocky Mountains along the western slope of the Continental Divide in southeastern British Columbia. Yoho NP is bordered by Kootenay National Park on the southern side and Banff National Park on the eastern side...

, Glacier National Park
Glacier National Park (Canada)
Glacier National Park is one of seven national parks in British Columbia, and is part of a system of 43 parks and park reserves across Canada. It protects a portion of the Columbia Mountains. It also contains the Rogers Pass National Historic Site, designated for its importance in the construction...

, and Mount Revelstoke National Park
Mount Revelstoke National Park
Mount Revelstoke National Park is located adjacent to the city of Revelstoke, British Columbia, Canada. The park is relatively small for a national park, covering 260 square kilometres. It is located in the Selkirk Mountains and was founded in 1914...

. Hells Canyon
Hells Canyon
Hells Canyon is a wide canyon located along the border of eastern Oregon and western Idaho in the United States. It is North America's deepest river gorge at and part of the Hells Canyon National Recreation Area....

, the deepest gorge in North America, and the Columbia Gorge are in the watershed. Vegetation varies widely, ranging from Western hemlock and Western redcedar
Thuja plicata
Thuja plicata, commonly called Western or pacific red cedar, giant or western arborvitae, giant cedar, or shinglewood, is a species of Thuja, an evergreen coniferous tree in the cypress family Cupressaceae native to western North America...

 in the moist regions to sagebrush
Sagebrush
Sagebrush is a common name of a number of shrubby plant species in the genus Artemisia native to western North America;Or, the sagebrush steppe ecoregion, having one or more kinds of sagebrush, bunchgrasses and others;...

 in the arid regions. The watershed provides habitat for 609 known fish and wildlife species, including the bull trout
Bull trout
The bull trout, Salvelinus confluentus, is a char of the family Salmonidae native to northwestern North America. Historically, S. confluentus has been known as the "Dolly Varden" , but was re-classified as a separate species in 1980. Bull trout are listed as a threatened species under the U.S....

, Bald Eagle
Bald Eagle
The Bald Eagle is a bird of prey found in North America. It is the national bird and symbol of the United States of America. This sea eagle has two known sub-species and forms a species pair with the White-tailed Eagle...

, gray wolf
Gray Wolf
The gray wolf , also known as the wolf, is the largest extant wild member of the Canidae family...

, grizzly bear
Grizzly Bear
The grizzly bear , also known as the silvertip bear, the grizzly, or the North American brown bear, is a subspecies of brown bear that generally lives in the uplands of western North America...

, and Canada lynx
Canada Lynx
The Canada lynx or Canadian lynx is a North American mammal of the cat family, Felidae. It is a close relative of the Eurasian Lynx . Some authorities regard both as conspecific. However, in some characteristics the Canada lynx is more like the bobcat than the Eurasian Lynx...

.

The World Wide Fund for Nature
World Wide Fund for Nature
The World Wide Fund for Nature is an international non-governmental organization working on issues regarding the conservation, research and restoration of the environment, formerly named the World Wildlife Fund, which remains its official name in Canada and the United States...

 (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
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....

. 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
Glacier
A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...

 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
Shoshone Falls
Shoshone Falls is a waterfall on the Snake River located approximately five miles east of Twin Falls, Idaho. Sometimes called the "Niagara of the West," Shoshone Falls is 212 feet high—45 feet higher than Niagara Falls—and flows over a rim 1,000 feet wide.A park overlooking the waterfall is...

, 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's 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
Interstate 5
Interstate 5 is the main Interstate Highway on the West Coast of the United States, running largely parallel to the Pacific Ocean coastline from Canada to Mexico . It serves some of the largest cities on the U.S...

 corridor, especially in the Portland-Vancouver urban area. High densities are also found around Spokane, Washington
Spokane, Washington
Spokane is a city located in the Northwestern United States in the state of Washington. It is the largest city of Spokane County of which it is also the county seat, and the metropolitan center of the Inland Northwest region...

, and Boise, Idaho
Boise, Idaho
Boise is the capital and most populous city of the U.S. state of Idaho, as well as the county seat of Ada County. Located on the Boise River, it anchors the Boise City-Nampa metropolitan area and is the largest city between Salt Lake City, Utah and Portland, Oregon.As of the 2010 Census Bureau,...

. 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
Deschutes County, Oregon
-National protected areas:* Deschutes National Forest * Newberry National Volcanic Monument-Demographics:As of the census of 2000, there were 115,367 people, 45,595 households, and 31,962 families residing in the county. The population density was 38 people per square mile . There were 54,583...

 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
Yakima, Washington
Yakima is an American city southeast of Mount Rainier National Park and the county seat of Yakima County, Washington, United States, and the eighth largest city by population in the state itself. As of the 2010 census, the city had a total population of 91,196 and a metropolitan population of...

 and the Tri-Cities
Tri-Cities, Washington
The Tri-Cities is a mid-sized metropolitan area in the southeastern part of the U.S. state of Washington, consisting of three neighboring cities: Kennewick, Pasco, and Richland. The cities are located at the confluence of the Yakima, Snake, and Columbia rivers in the semi-arid region of...

 area. Projections for the coming decades assume growth throughout the watershed, including the interior. The Canadian part of the Okanagan
Okanagan
The Okanagan , also known as the Okanagan Valley and sometimes as Okanagan Country is a region located in the Canadian province of British Columbia defined by the basin of Okanagan Lake and the Canadian portion of the Okanagan River. As of 2009, the region's population is approximately 350,927. The...

 subbasin is also growing rapidly.

Climate varies greatly from place to place within the watershed. Elevation ranges from sea level
Sea level
Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...

 at the river mouth to more than 14000 feet (4,267.2 m) in the mountains, and temperatures vary with elevation. The highest peak is Mount Rainier
Mount Rainier
Mount Rainier is a massive stratovolcano located southeast of Seattle in the state of Washington, United States. It is the most topographically prominent mountain in the contiguous United States and the Cascade Volcanic Arc, with a summit elevation of . Mt. Rainier is considered one of the most...

, at 14411 feet (4,392.5 m). 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
Shrub-steppe
Shrub-steppe is a type of low rainfall natural grassland. Shrub-steppes are distinguishable from deserts, which are too dry to support a noticeable cover of perennial grasses or other shrubs, while the shrub-steppe has sufficient moisture levels to support a cover of perennial grasses and/or...

 regions with Continental climate
Continental climate
Continental climate is a climate characterized by important annual variation in temperature due to the lack of significant bodies of water nearby...

 patterns, precipitation maximums occur in early summer. Annual precipitation varies from more than 100 inches (254 cm) a year in the Cascades to less than 8 inches (20.3 cm) in the interior. Much of the watershed gets less than 12 inches (30.5 cm) 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
Continental Divide
The Continental Divide of the Americas, or merely the Continental Gulf of Division or Great Divide, is the name given to the principal, and largely mountainous, hydrological divide of the Americas that separates the watersheds that drain into the Pacific Ocean from those river systems that drain...

 separates the Columbia watershed from the Mississippi
Mississippi River
The Mississippi River is the largest river system in North America. Flowing entirely in the United States, this river rises in western Minnesota and meanders slowly southwards for to the Mississippi River Delta at the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains...

-Missouri
Missouri River
The Missouri River flows through the central United States, and is a tributary of the Mississippi River. It is the longest river in North America and drains the third largest area, though only the thirteenth largest by discharge. The Missouri's watershed encompasses most of the American Great...

 watershed, which empties into the Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...

. To the northeast, mostly along the southern border between British Columbia and Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...

, the Continental Divide separates the Columbia watershed from the Nelson
Nelson River
The Nelson River is a river of north-central North America, in the Canadian province of Manitoba. Its full length is , it has mean discharge of , and has a drainage basin of , of which is in the United States...

-Lake Winnipeg
Lake Winnipeg
Lake Winnipeg is a large, lake in central North America, in the province of Manitoba, Canada, with its southern tip about north of the city of Winnipeg...

-Saskatchewan
Saskatchewan River
The Saskatchewan River is a major river in Canada, approximately long, flowing roughly eastward across Saskatchewan and Manitoba to empty into Lake Winnipeg...

 watershed, which empties into Hudson Bay
Hudson Bay
Hudson Bay , sometimes called Hudson's Bay, is a large body of saltwater in northeastern Canada. It drains a very large area, about , that includes parts of Ontario, Quebec, Saskatchewan, Alberta, most of Manitoba, southeastern Nunavut, as well as parts of North Dakota, South Dakota, Minnesota,...

. The Mississippi and Nelson watersheds are separated by the Laurentian Divide
Laurentian Divide
The Laurentian Divide or Northern Divide is a continental divide dividing the direction of water flow in eastern and southern Canada and the northern Midwestern United States. Water north of the height of land flows to the Arctic Ocean by rivers to Hudson Bay or directly to the Arctic...

, which meets the Continental Divide at Triple Divide Peak
Triple Divide Peak (Montana)
-See also:* Continental Divide of the Americas* Mountains and mountain ranges of Glacier National Park...

 near the headwaters of the Columbia's Flathead River
Flathead River
The Flathead River, in the northwestern part of the U.S. state of Montana, originates in the Rocky Mountains near Glacier National Park and flows southwest into Flathead Lake, then after a journey of , empties into the Clark Fork. The river is part of the Columbia River drainage basin, as the Clark...

 tributary. This point marks the meeting of three of North America's main drainage patterns, to the Pacific Ocean, to Hudson Bay, and to the Atlantic Ocean via the Gulf of Mexico.

Further north along the Continental Divide, a short portion of the combined Continental and Laurentian divides separate the Columbia watershed from the MacKenzie
Mackenzie River
The Mackenzie River is the largest river system in Canada. It flows through a vast, isolated region of forest and tundra entirely within the country's Northwest Territories, although its many tributaries reach into four other Canadian provinces and territories...

-Slave
Slave River
The Slave River is a Canadian river that flows from Lake Athabasca in northeastern Alberta and empties into Great Slave Lake in the Northwest Territories....

-Athabasca
Athabasca River
The Athabasca River originates from the Columbia Glacier of the Columbia Icefield in Jasper National Park in Alberta, Canada...

 watershed, which empties into the Arctic Ocean
Arctic Ocean
The Arctic Ocean, located in the Northern Hemisphere and mostly in the Arctic north polar region, is the smallest and shallowest of the world's five major oceanic divisions...

. 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
Snow Dome (Canada)
Snow Dome is a mountain located on the Continental Divide in the Columbia Icefield, at the intersection of Banff National Park, and Jasper National Park, on the Alberta and British Columbia border in Canada.The mountain was named in 1898 by J...

 (also known as Dome), near the northernmost bend of the Columbia River.

To the southeast, in western Wyoming, another divide separates the Columbia watershed from the Colorado
Colorado River
The Colorado River , is a river in the Southwestern United States and northwestern Mexico, approximately long, draining a part of the arid regions on the western slope of the Rocky Mountains. The watershed of the Colorado River covers in parts of seven U.S. states and two Mexican states...

-Green
Green River (Utah)
The Green River, located in the western United States, is the chief tributary of the Colorado River. The watershed of the river, known as the Green River Basin, covers parts of Wyoming, Utah, and Colorado. The Green River is long, beginning in the Wind River Mountains of Wyoming and flowing...

 watershed, which empties into the Gulf of California
Gulf of California
The Gulf of California is a body of water that separates the Baja California Peninsula from the Mexican mainland...

. The Columbia, Colorado, and Mississippi watersheds meet at Three Waters Mountain in the Wind River Range
Wind River Range
The Wind River Range , is a mountain range of the Rocky Mountains in western Wyoming in the United States. The range runs roughly NW-SE for approximately 100 miles . The Continental Divide follows the crest of the range and includes Gannett Peak, which at 13,804 feet , is the highest peak...

 of To the south, in Oregon, Nevada, Utah, Idaho, and Wyoming, the Columbia watershed is divided from the Great Basin
Great Basin
The Great Basin is the largest area of contiguous endorheic watersheds in North America and is noted for its arid conditions and Basin and Range topography that varies from the North American low point at Badwater Basin to the highest point of the contiguous United States, less than away at the...

, whose several watersheds are endorheic, not emptying into any ocean but rather drying up or sinking into sump
Sump
A sump is a low space that collects any often-undesirable liquids such as water or chemicals. A sump can also be an infiltration basin used to manage surface runoff water and recharge underground aquifers....

s. Great Basin watersheds that share a border with the Columbia watershed include Harney Basin
Harney Basin
The Harney Basin is a structural basin in southeastern Oregon in the United States at the northwestern corner of the Great Basin. One of the least populated areas of the contiguous United States, it is located largely in northern Harney County, bounded on the north and east by the Columbia Plateau,...

, Humboldt River
Humboldt River
The Humboldt River runs through northern Nevada in the western United States. At approximately long it is the second longest river in the Great Basin, after the Bear River. It has no outlet to the ocean, but instead empties into the Humboldt Sink...

, and Great Salt Lake
Great Salt Lake
The Great Salt Lake, located in the northern part of the U.S. state of Utah, is the largest salt water lake in the western hemisphere, the fourth-largest terminal lake in the world. In an average year the lake covers an area of around , but the lake's size fluctuates substantially due to its...

. The associated triple divide points are Commissary Ridge North, Wyoming, and Sproats Meadow Northwest, Oregon. To the north, mostly in British Columbia, the Columbia watershed borders the Fraser River
Fraser River
The Fraser River is the longest river within British Columbia, Canada, rising at Fraser Pass near Mount Robson in the Rocky Mountains and flowing for , into the Strait of Georgia at the city of Vancouver. It is the tenth longest river in Canada...

 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
Klamath River
The Klamath River is an American river that flows southwest through Oregon and northern California, cutting through the Cascade Range to empty into the Pacific Ocean. The river drains an extensive watershed of almost that stretches from the high desert country of the Great Basin to the temperate...

 in Oregon and California and the Puget Sound
Puget Sound
Puget Sound is a sound in the U.S. state of Washington. It is a complex estuarine system of interconnected marine waterways and basins, with one major and one minor connection to the Strait of Juan de Fuca and the Pacific Ocean — Admiralty Inlet being the major connection and...

 Basin in Washington.

Major tributaries

The Columbia receives more than 60 significant tributaries
Tributary
A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

. The four largest that empty directly into the Columbia (measured either by discharge
Discharge (hydrology)
In hydrology, discharge is the volume rate of water flow, including any suspended solids , dissolved chemical species and/or biologic material , which is transported through a given cross-sectional area...

 or by size of watershed) are the Snake River
Snake River
The Snake is a major river of the greater Pacific Northwest in the United States. At long, it is the largest tributary of the Columbia River, the largest North American river that empties into the Pacific Ocean...

 (mostly in Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....

), the Willamette River
Willamette River
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 long, lying entirely in northwestern Oregon in the United States...

 (in northwest Oregon), the Kootenay River
Kootenay River
The Kootenay is a major river in southeastern British Columbia, Canada and the northern part of the U.S. states of Montana and Idaho. It is one of the uppermost major tributaries of the Columbia River, which is the largest North American river that empties into the Pacific Ocean...

 (mostly in British Columbia), and the Pend Oreille River
Pend Oreille River
The Pend Oreille River is a tributary of the Columbia River, approximately long, in northern Idaho and northeastern Washington in the United States, as well as southeastern British Columbia in Canada. In its passage through British Columbia its name is spelled Pend-d'Oreille River...

 (mostly in northern Washington and Idaho, also known as the lower part of the Clark Fork
Clark Fork (river)
The Clark Fork is a river in the U.S. states of Montana and Idaho, approximately long. The largest river by volume in Montana, it drains an extensive region of the Rocky Mountains in western Montana and northern Idaho in the watershed of the Columbia River, flowing northwest through a long...

). Each of these four averages more than 20000 cuft/s and drains an area of more than 20000 mi2.

The Snake is by far the largest tributary. Its watershed of 108000 mi2 is larger than the state of Idaho. Its discharge is nearly equal to the Columbia's at the rivers' confluence. Compared to the Columbia above the confluence, the Snake is longer (113%), and its drainage basin is larger (104%).

The Pend Oreille river system (including its main tributaries, the Clark Fork and Flathead rivers) is also similar in size to the Columbia at their confluence. Compared to the Columbia River above the two rivers' confluence, the Pend Oreille-Clark-Flathead is nearly as long (about 86%), its basin about three-fourths as large (76%), and its discharge over a third (37%).
Tributary
Tributary
A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

Average discharge Drainage basin
ft3/s m3/s mi2 km2
Snake River
Snake River
The Snake is a major river of the greater Pacific Northwest in the United States. At long, it is the largest tributary of the Columbia River, the largest North American river that empties into the Pacific Ocean...

569001,611.2 107500 mi2
Willamette River
Willamette River
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 long, lying entirely in northwestern Oregon in the United States...

374001,059.1 11460 mi2
Kootenay River
Kootenay River
The Kootenay is a major river in southeastern British Columbia, Canada and the northern part of the U.S. states of Montana and Idaho. It is one of the uppermost major tributaries of the Columbia River, which is the largest North American river that empties into the Pacific Ocean...

 (Kootenai)
30650867.9 19420 mi2
Pend Oreille River
Pend Oreille River
The Pend Oreille River is a tributary of the Columbia River, approximately long, in northern Idaho and northeastern Washington in the United States, as well as southeastern British Columbia in Canada. In its passage through British Columbia its name is spelled Pend-d'Oreille River...

26430748.4 25800 mi2
Cowlitz River
Cowlitz River
The Cowlitz River is a river in the state of Washington in the United States, a tributary of the Columbia River. Its tributaries drain a large region including the slopes of Mount Rainier, Mount Adams, and Mount St. Helens....

9140258.8 2586 mi2
Spokane River
Spokane River
The Spokane River is a tributary of the Columbia River, approximately long, in northern Idaho and eastern Washington in the United States. It drains a low mountainous area east of the Columbia, passing through the city of Spokane, Washington.-Description:...

7900223.7 6680 mi2
Lewis River
Lewis River (Washington)
The Lewis River is a tributary of the Columbia River, about long, in southwestern Washington in the United States. It drains part of the Cascade Range north of the Columbia River. The drainage basin of the Lewis River covers about . The river's mean annual discharge is about . Unlike nearby Lewis...

6125173.4 1046 mi2
Deschutes River 5845165.5 10700 mi2
Yakima River
Yakima River
The Yakima River is a tributary of the Columbia River in south central and eastern Washington State, named for the indigenous Yakama people. The length of the river from headwaters to mouth is , with an average drop of .-Course:...

3542100.3 6150 mi2
Wenatchee River
Wenatchee River
The Wenatchee River is a river in the U.S. state of Washington, originating at Lake Wenatchee and flowing southeast for , emptying into the Columbia River immediately north of Wenatchee, Washington...

307987.2 1350 mi2
Okanogan River
Okanogan River
The Okanogan River is a tributary of the Columbia River, approximately 115 mi long, in southern British Columbia and north central Washington...

303986.1 8340 mi2
Kettle River
Kettle River (Columbia River)
The Kettle River is a tributary of the Columbia River in northeastern Washington in the United States and southeastern British Columbia in Canada. Its drainage basin is large, of which are in Canada and in the United States.-Course:...

292582.8 4200 mi2
Sandy River
Sandy River (Oregon)
The Sandy River is a tributary of the Columbia River in northwestern Oregon in the United States. Measured by a United States Geological Survey gauge downstream of the Sandy's confluence with the Bull Run River, from the mouth, the river's average discharge is . The maximum daily recorded flow...

225763.9 508 mi2
John Day River
John Day River
The John Day River is a tributary of the Columbia River, approximately long, in northeastern Oregon in the United States. Undammed along its entire length, the river is the third longest free-flowing river in the conterminous United States. There is extensive use of its waters for irrigation. Its...

206058.3


See also

  • Benson raft
    Benson raft
    The Benson raft was a huge sea-going log raft designed to reliably transport millions of board feet of timber at one time through the open ocean. This practical transportation method was first used on the Pacific coast in 1906 by Simon Benson, a lumber baron of Portland, Oregon, in the United...

    , a huge sea-going log raft designed to reliably transport millions of board feet of timber from Oregon / Washington area
  • Columbia Mountains
    Columbia Mountains
    The Columbia Mountains are a group of mountain ranges located in southeastern British Columbia, and partially in Montana, Idaho and Washington. The mountain range covers 135,952 km² . The range is bounded by the Rocky Mountain Trench on the east, and the Kootenay River on the south; their...

  • Columbia Park, Kennewick
    Columbia Park, Kennewick
    The Columbia Park is a recreational area with 4.5 miles of shoreline of the Columbia River located in the city of Kennewick in the U.S. state Washington...

    , a 400 acres (161.9 ha) recreational area
  • Columbia River Estuary
    Columbia River Estuary
    The Columbia River Estuary is an estuary and a bay on the Oregon-Washington border and the Pacific Coast of the United States.If the Columbia River Estuary is defined by the region that experiences ocean tides, then the estuary actually extends up the Columbia River to the Bonneville Dam, and up...

  • Columbia River Maritime Museum
    Columbia River Maritime Museum
    The Columbia River Maritime Museum is a museum of maritime history located about ten miles from the mouth of the Columbia River in Astoria, Oregon, U.S.. It has a national reputation for the quality of its exhibits and the scope of its collections and was the first museum in Oregon to meet...

     in Astoria, Oregon
  • Empire Builder
    Empire Builder
    The Empire Builder is a passenger train route operated by Amtrak in the Midwestern and Northwestern United States. It is Amtrak's busiest long-distance route and busiest daily train, carrying more than 500,000 travelers annually since 2007. Overall, it is the railroad's 10th-busiest line. Before...

    , an Amtrak rail line that follows the river from Portland to Pasco, Washington
  • Gray sails the Columbia River
    Gray sails the Columbia River
    In May of 1792, American merchant sea captain Robert Gray sailed into the Columbia River, becoming the first recorded European to navigate into it. The voyage, conducted on the Columbia Rediviva, a privately owned ship, was eventually used as a basis for the United States' claim on the Pacific...

    , an account of Captain Gray's entry into the river's mouth
  • Historic Columbia River Highway, a scenic highway on the Oregon side
  • List of ecoregions in North America (CEC)
  • List of ecoregions in Oregon
  • List of longest main-stem rivers in the United States
  • List of longest rivers of Canada
  • List of longest streams of Oregon
  • List of rivers of British Columbia
  • List of rivers of Oregon
  • List of rivers of Washington
  • Okanagan Trail
    Okanagan Trail
    The Okanagan Trail was an inland route to the Fraser Canyon Gold Rush from the Lower Columbia region of the Washington and Oregon Territories in 1858-1859...

    , a historic trail that followed the Columbia and Okanagan rivers

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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