Columbia River

• Category: Inland Aquatic Biomes.
• Geographic Location: North America.
• Summary: The largest river in the Pacific Northwest of North America, the Columbia River is known for historically abundant salmon runs, but is fragmented by hydroelectric dams.

The Columbia River basin encompasses 279,500 square miles (724,000 square kilometers) in Canada and the western United States. The major tributaries are the Snake, Yakima, and Willamette Rivers. The Columbia River is 1,200 miles (2,000 kilometers) long, and is the fourth-largest river in the United States by volume, with an average discharge at the mouth of 264,860 cubic feet (7,500 cubic meters) per second, more than any other river draining to the Pacific Ocean from North America.

The river is managed through a treaty between the United States and Canada that aims to address the management of flood risks, ensure economical power supply, and improve the ecosystem of the river. In 2018, the two countries entered into new negotiations to attempt to modernize their treaty. As of August 2023, the two countries had undergone eighteen rounds of negotiations. On July 11, 2024, the United States announced that it had reached an agreement in principle with Canada.

The source of the Columbia River is in the Rocky Mountains of northern Montana. The river proper begins in the Canadian province of British Columbia, flows south through the states of Washington and Oregon, and eventually empties into the Pacific Ocean. The river drains portions of British Columbia, Alberta, Montana, Wyoming, Idaho, Utah, Nevada, Oregon, and Washington, with some of the water originating as snowmelt. The geology of the basin is largely glaciated in the upper reaches, and unglaciated in the lower reaches. The basin includes parts of the uplift Rocky Mountains and the volcanic Cascade Mountains, punctuated by low valleys and plateaus.

The catastrophic Missoula floods, occurring near the end of the last ice age, shaped the geology of the Columbia River basin. Ice-dam failures of glacial Lake Missoula occurred at least 40 times, resulting in floods with discharges 10 times higher than the combined flow of all the rivers in the world. These floods created many prominent landforms of the region, including the scablands of eastern Washington, the Columbia River Gorge, and many smaller tributary canyons. Depositional areas from the floods also created rich sediments, including the Palouse region of eastern Washington and the Willamette River Valley of western Oregon, making them valuable agricultural areas.

Precipitation in the Columbia River basin is strongly seasonal, occurring mainly in the winter months. Due to elevation differences and the fact that much of the basin is quite arid—located in the rain shadow of the Cascade Mountains—precipitation and temperatures have a wide range within the drainage region.

Wildlife

The uplands in the region are typically dominated by coniferous forests, grasslands, and shrub steppe ecosystems. Much of the grasslands area has suffered degradation due to overgrazing and the introduction of varied croplands. The US Geological Survey reports approximately 1.7 million acres (688,000 hectares) of irrigated crops in the greater Columbia Basin. The World Wildlife Fund classifies the basin into three freshwater ecoregions: Columbia Glaciated, Columbia Unglaciated, and Upper Snake.

The Columbia River system was once one of the largest salmon-producing rivers in the world. Salmon were present in the river up to 12,000 years ago; the abundant runs of salmon became the cornerstone of indigenous hunter-gatherer societies of the basin, and the region was an important area for commerce and culture. The availability of marine-derived nutrients were important to the people of the area and to the ecosystem itself, as postspawn carcasses of adult salmon annually reseeded the basin with ocean-sourced nutrients.

The trophic ecology in less affected areas is now typically dominated by a rich and productive array of invertebrates, although impounded, or dammed, areas have been dramatically altered. The fish diversity of the Columbia River is low, while endemism (species found nowhere else on Earth) is high. The sheer number of migratory salmon runs make up for the low diversity, and runs of Chinook salmon, chum salmon, coho salmon, sockeye salmon, and steelhead trout were enormous before 1850.

Large runs of migratory Pacific lamprey, cutthroat trout, white sturgeon, and eulachon were also present once, and their numbers have been dramatically reduced in recent years. It is estimated that recent runs of salmon are only 3 to 20 percent of original numbers. Extensive freshwater mussel beds were once abundant as well, harvested by Native Americans. The impounded reaches of the Columbia River basin have made juvenile and adult salmon and sturgeon migrations more difficult, while improving habitat for nonnative fish like walleye, catfish, and smallmouth bass.

Along with the abundance of fish, a limited number of marine mammals traverse the Columbia River. In the lower Columbia River common visitors include Pacific harbor seals, California sea lions, and Stellar sea lions. While less frequent, Northern fur seals and elephant seals have been spotted in the river, observed in small numbers, and rarely present for long periods.

Economy

The Columbia River and its surrounding areas have served as a hub for a number of industries and has long been a source of hydroelectricity. When the fur trade boomed in Canada and the Pacific Northwest at the end of the 18th and early 19th centuries, the Columbia River area served as a place for traders to spend the winter. Later, a triangular fur trade route was established between Lima, Peru, the Pacific Northwest, and Canton (Guangzhou) in China, and the Columbia River area was a stop along the route. In the 1860s, on the heels of the California Gold Rush, gold was found in the sands of the Columbia River. Prospectors flocked to the area; gold-strike cities like Elk City, Idaho grew up seemingly overnight with the influx of those looking for gold. The cities died as quickly once the gold supply ran out.

Fishing salmon and hatcheries in the Columbia River Basin have been a major industry for the river as well. Before European settlement, Celilo Falls (today on the border of Washington and Oregon) was a significant salmon fishing spot for Indigenous tribes and became a major trading post, sometimes referred to as "the original Wall Street of North America." The river basin has been the site of hatcheries and fish farms since the 1800s. Additionally, from 1938 through the end of the 20th century, the Colombia River area was a major producer of aluminum.

Human Impact

Prehistorically, the Columbia River had salmon runs that made the area an important gathering and cultural center for many indigenous peoples of the region. The Lewis and Clark expedition of the early 1800s charted the area for the incoming American settlers. The basin became an important area for ranching, timber harvesting, and agriculture. The river provided transportation for people and goods, water for irrigation, and (in recent history) power production. The basin's high gradient results in high-velocity flows, which are ideal for producing hydroelectric power. As such, fourteen major dams have been constructed on the mainstem Columbia and Snake Rivers, with many small dams built for hydropower and flood control on smaller tributaries.

Fish ladders are present on many of the dams, allowing passage of adult fish, but upstream migration is permanently blocked by the Grand Coulee Dam on the Upper Columbia River and by the Hells Canyon Dam on the Snake River. Free-flowing reaches of the Columbia River mainstem are rare, most notably the Hanford Reach in east-central Washington. Consequently, fourteen stocks of salmon species are listed as endangered or threatened under the US Endangered Species Act; other species and stocks are declining, and still others are extinct or extirpated. According to a 2020 report from Washington State, five of the fourteen endangered salmon species are listed as “in crisis.” Ten of the species are behind in conservation recovery goals. The quality of water in the Columbia River has also deteriorated over the past century due to agricultural runoff (such as nitrates), increased use of herbicides and pesticides, and logging practices. The alteration of river flows, fragmentation of the river, and other anthropogenic effects (such as hatcheries, habitat loss, and harvest) have directly threatened the historically abundant fish runs.

Fisheries restoration has been largely unsuccessful, although diverse and expensive restoration and mitigation actions are in place, including hatchery production, irrigation screening, and juvenile-dam-bypass systems. Management of the basin to conserve wild salmon is overseen by multiple entities, including federal (such as the Army Corps of Engineers); state; tribal agencies; and numerous power companies, notably the Bonneville Power Administration. These efforts are often confounded by the lack of a consistent management paradigm, further reducing prospects for successful recovery of salmon stocks.

Climate change is becoming an increasingly important component of water demand and supply forecasting in the biome. The potential consequences to water resources in the Columbia River basin associated with warmer temperatures and greater precipitation include a shift from snow to rain precipitation in winter. The resultant reduced snowpacks, higher winter streamflows, increased flood potential, and lower summer flows will exacerbate streambank erosion, nutrient deposition, and habitat disruption in many reaches of the basin.

Bibliography

Allen, John E., Marjorie Burns, and Sam C. Sargent. Cataclysms on the Columbia. Portland, OR: Timber Press, 1986.

Chatters, James C. “A Paleoscience Approach to Estimating the Effects of Climatic Warming on Salmonid Fisheries of the Columbia River Basin.” Canadian Special Publication of Fisheries and Aquatic Sciences 121, no. 1 (1995).

"Columbia River History." Northwest Power and Conservation Council, www.nwcouncil.org/history/index/. Accessed 5 Nov. 2024.

Fazio, Marie. "Northwest’s Salmon Population May Be Running Out of Time." The New York Times, 20 Jan. 2021, www.nytimes.com/2021/01/20/climate/washington-salmon-extinction-climate-change.html. Accessed 5 Nov. 2024.

Meengs, Chad C. and Robert T. Lackey. “Estimating the Size of Historical Oregon Salmon Runs.” Reviews in Fisheries Science 13, no. 1 (2005).

“Rebuilding Salmon and Steelhead in the Columbia River Basin.” National Oceanic and Atmospheric Administration, 30 Sep. 2022, www.noaa.gov/news-release/rebuilding-salmon-and-steelhead-in-columbia-river-basin#:~:text=The%20recommended%20suite%20of%20actions,harvest%20and%20reconnecting%20floodplain%20habitat. Accessed 5 Nov. 2024.

Stanford, Jack A., et al. “Columbia River Basin.” In A. C. Benke and C. C. Cushing, eds., Rivers of North America. Burlington, MA: Elsevier Academic Press, 2005.

“Summary of the Agreement in Principle to Modernize the Columbia River Treaty Regime.” U.S. Department of State, 11 Jul. 2024, www.state.gov/summary-of-the-agreement-in-principle-to-modernize-the-columbia-river-treaty-regime/. Accessed 5 Nov. 2024.

White, Richard. The Organic Machine: The Remaking of the Columbia River. New York: Hill and Wang, 1995.

Williams, Richard, N. Return to the River: Restoring Salmon to the Columbia River. San Diego, CA: Elsevier, 2005.