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Columbia River

About EPA's Work in the Columbia River Basin

EPA and other federal agencies, along with states, tribes, local governments, nonprofit organizations, and individual citizens are all engaged in efforts to restore and improve the quality of the water, land and air within the basin. The sheer size and geography of the watershed requires unprecedented cooperation to accomplish these critical ecosystem restoration efforts.

On this page:

About the Columbia River Basin

Map of the Columbia River Watershed

Columbia River watershed. View larger map.

The Columbia River watershed covers a major portion of North America, including parts of seven states and British Columbia, Canada. It provides drainage for hundreds of rivers, creeks, and streams - covering an area of more than 260,000 square miles. The Columbia River itself flows over 1,200 miles from its source in the Canadian Rockies to the Pacific Ocean. It's the second largest river in the U.S. in volume of water flow, behind only the Mississippi River.

The watershed provides an important backdrop for urban development, agriculture, transportation, recreation, fisheries and hydropower in the western United States. But heavy use has also caused significant declines in the salmon population, which were once the largest in the world. The tribal people of the region have depended on these salmon for thousands of years for food, trade, cultural and spiritual use.

Key Projects in the Upper Columbia River

Grand Coulee Dam on the Columbia River in Washington. Photo courtesy of U.S. Bureau of Reclamation.The free-flowing headwaters of the Columbia River are located in the Canadian Rockies where snowmelt and spring water fill Columbia Lake near British Columbia's border with Alberta. From the headwaters, the river flows 600 miles downstream and swells behind Grand Coulee Dam. Grand Coulee is the first of 14 dams along the Columbia River.

Upper Columbia River Remedial Investigation and Feasibility Study

EPA is studying contamination in the Columbia River from the U.S./Canada border to the Grand Coulee Dam and surrounding upland areas. The study is called a Remedial Investigation and Feasibility Study (RI/FS).

Past studies by federal and state agencies have shown increased levels of heavy metals such as arsenic, lead, cadmium, copper, mercury and zinc, and other contaminants like dioxins and furans.

Bunker Hill Superfund Site

The Bunker Hill Mining and Metallurgical Superfund Site, located in northern Idaho and eastern Washington, was listed on the Superfund National Priorities List in 1983.

EPA and its partners have made a great deal of cleanup progress, reducing risks to the health of people and the environment. More work remains, and the cleanup is expected to take decades. It's one of the most vast and complex Superfund sites in the U.S., within one of the largest historical mining districts in the world.

The site includes mining-contaminated areas in the Coeur d'Alene River corridor, adjacent floodplains, downstream water bodies, tributaries, and fill areas. It also encompasses the 21 square mile Bunker Hill "Box", located in the area surrounding the historical smelter operation.

Spokane River Regional Toxics Task Force

The Spokane River Regional Toxics Task Force leads efforts to find and reduce toxic compounds in the Spokane River. Their goal is to develop a comprehensive plan to bring the Spokane River into compliance with water quality standards for PCBs (polychlorinated biphenyls). These pollutants exceed water quality standards in several segments of the river.

Key Projects in the Mid-Columbia River

The middle portion of the Columbia River runs over 450 miles from Grand Coulee Dam to Bonneville Dam, where the river serves as the boundary between Oregon and Washington. The Snake River flows in from Idaho and is the largest tributary of the Columbia River. The Snake was once home to at least a third of the salmon run in the Basin.

Hanford Cleanup Site in Richland, Washington

The U.S. Department of Energy Hanford Site, located near the City of Richland, Washington, was established to produce nuclear materials for national defense. The Hanford Site was placed on EPA's National Priorities List of contaminated sites in 1989. The Department of Energy entered into the Tri-Party Agreement with EPA and the Washington Department of Ecology, establishing the legal framework and schedule for cleaning up Hanford. EPA has an office in Richland to help oversee the cleanup.

Walla Walla River Basin Pesticide Stewardship Project

Monitoring in two tributaries in the Walla Walla River watershed near Milton-Freewater, Oregon showed a stunning 90 to 95% reduction in the average concentrations of chemical chlorpyrifos (Lorsban) - an insecticide used to control pests on fruit trees and other crops - between 2006 and 2011. The dramatic reduction coincides with a wide range of pesticides management practices implemented by farmers since 2006, including:

  • Reducing pesticide drift, which happens when pesticides are applied in ways that allow chemical droplets to move off the farm site, such as during windy weather.
  • Installing weather stations to ensure pesticides are applied when weather conditions are best.
  • Using non-chemical pest management techniques such as disrupting the mating cycles of pest insects.
  • Using less toxic alternative chemicals to control pests.

Similar dramatic reductions in average concentrations of the herbicide diuron (Karmex) were also observed in those same tributaries between 2009 and 2013.

The local irrigation districts in the areas reduced the use of diuron by relying on mechanical controls for weeds on ditch banks, as well as occasional spot spraying of a less toxic and persistent herbicide. The pesticides monitoring was part of an Oregon Pesticide Stewardship Partnership Project - a collaborative program funded largely by EPA grants that involves participation by the Oregon Department of Environmental Quality, watershed councils, Oregon State University Extension Service, Oregon Department of Agriculture, agricultural producer groups, tribes, soil and water conservation districts, and local chemical suppliers.

The program also helps organize pesticide collection events for old, unusable pesticides that were used in the past - such as DDT - to make sure they do not get into the environment. In July of 2014, over 15,000 pounds of waste pesticides were collected from growers and pesticide applicators on the Oregon side of the Walla Walla Watershed.

Questions about Oregon Pesticide Stewardship Partnerships? Contact Kevin Masterson (, Oregon Department of Environmental Quality; or Mary Lou Soscia (, EPA.

Indian Creek Watershed Outreach in Nampa, Idaho

Indian Creek flows through Nampa, Idaho, and is a tributary of the Snake River. EPA has awarded the City of Nampa two grants to develop a public education and outreach campaign on stormwater management focusing on the Hispanic community (the Boise/Nampa/Caldwell area is home to one of the fastest-growing Hispanic populations in Idaho).

Nampa's Stormwater Program Team is working to increase the community's awareness of stormwater impacts on water quality in Indian Creek and other local water bodies. These efforts include:

  • Bilingual stormwater website which won the 2012 Idaho Press Club competition.
  • Bilingual tip sheets for stormwater management.
  • Bilingual storybook that teaches children about the impacts of stormwater runoff.
  • Bilingual stormwater/watershed educational signage at City Acres Park, a popular local park adjacent to Indian Creek.

Corporate partners and the local school district are helping with stream cleanup days to foster increased community involvement.

EPA has continued a partnership with the City of Nampa to provide EPA Urban Waters funding to continue work efforts to increase community awareness and participation.

Learn more about the Indian Creek watershed project and EPA's "Making a Visible Difference" program:

Questions about the Indian Creek watershed project? Contact Mary Lou Soscia (, 503-326-5873.

Key Projects in the Lower Columbia River

Astoria Bridge
Iconic Astoria Bridge near the mouth of the Columbia River.

The lower portion of the Columbia River stretches 146 miles from Bonneville Dam - the last of 14 dams on the river - to the Pacific Ocean. Another large tributary, the Willamette River, joins the Columbia downstream from Bonneville. When the Columbia finally meets the ocean more than 1,200 miles from its source in the Canadian Rockies, it flows in with such force that it spills a plume of freshwater four miles out into the ocean, creating an estuary of vital importance to people and wildlife.

Portland Harbor Superfund Site

The Portland Harbor Superfund site in Portland, Oregon, is the result of more than a century of industrial use along the Willamette River. Sediment is contaminated with many hazardous substances, including heavy metals, polychlorinated biphenyls (PCBs), polynuclear aromatic hydrocarbons (PAH), dioxin, and pesticides.

The cleanup investigation currently extends from lower Willamette River, approximately between the Broadway Bridge in downtown Portland and Sauvie Island.

Although we work and recreate along Portland Harbor, the primary way people are exposed to contamination there is by eating fish such as bass, catfish and carp. These fish, called resident fish, carry levels of chemical contaminants which may cause cancer or developmental problems. PCBs are the primary contaminant associated with most of the risk from eating resident fish. Young children, nursing infants and babies in the womb are the most sensitive to the chemicals.

Cleanup Progress in the Lower Columbia

Map showing environmental cleanup acreage in the lower Columbia River through 2015.Since 2006, 92.2 acres of contaminated sediments in the Lower Columbia River have been cleaned up as a result of state and federal actions. These 92.2 acres are among 400 acres of known contaminated sites in the Columbia River Basin.

Key cleanup sites include:

  • Ross Island, Portland (near mile 15 of the Willamette River).
  • Johnson Lake, Portland (south of the Columbia Slough).
  • Zidell, Portland.
  • ALCOA aluminum smelter, Vancouver, Washington.
  • Smaller sites along the Columbia Slough.

The cleanups in these areas provide a significant contribution to reducing toxics in the Columbia River.

Lower Columbia River Estuary Partnership

The Lower Columbia Estuary Partnership was established in 1995 and is one of 28 programs in EPA's National Estuary Program (NEP) that protects and restores an estuary of national significance.

Its mission is to improve the lower Columbia River by protecting and restoring ecosystems and enhancing clean water for current and future generations of fish, wildlife, and people. It is a collaborative program led by farmers, educators, businesses and economic interests, conservation groups, citizens, state governments, federal agencies, and tribal governments.

The Estuary Partnership restores and protects habitat, improves water quality, advances science, and provides information about the river to a range of audiences. It is a 501(c)3 non-profit corporation that works along the lower 146 miles of the Columbia River from Bonneville Dam to the Pacific Ocean.