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Rivers & Watersheds

During Orca Month in 2022, through stories and videos, we'll explore some of the watersheds and rivers that are essential to Pacific Northwest salmon and vitally important to the endangered Southern Resident orcas and a healthy marine ecosystem. 


  • Amanda Colbert

This week, we continue further down the coast to explore the Columbia-Snake Rivers and their connection to northwest salmon and Southern Resident orcas.

The Columbia River headwaters originate in Columbia Lake, British Columbia, and travel 1,253 miles from its source to its mouth where it meets the Pacific Ocean at Astoria, Oregon. By volume, the Columbia River is the 4th largest river in North America, traveling through four mountain ranges and draining more water into the Pacific Ocean than any other river in North or South America. Historically, 10-16 million wild salmon and steelhead would move into the Columbia River aimed at spawning sites upriver. Certain salmon runs would travel as far inland as some of the tributary waters in British Columbia, Canada.

The Snake River headwaters originate from the western side of Wyoming in the Rocky Mountains, flowing due west through Idaho before making a sharp turn north along the Idaho/Oregon state line. The Snake flows 1,078 miles until it meets the Columbia River at the Tri-Cities in Washington State and is the largest tributary waterway of the Columbia. The Snake River watershed covers roughly 108,000 square miles and spans six states including Wyoming, Idaho, Nevada, Utah, Oregon, and Washington. Historically, 2-4 million wild salmon and steelhead would move into the Snake River aimed at spawning sites as far inland as Central Idaho. The Snake River basin once produced roughly half of all spring Chinook returning to Columbia basin rivers and tributaries. These “Springers” were/are highly desirable to tribes and fishermen because of their high-fat content, and vital to the Southern Resident orcas for the same reason.

These two rivers unify a large portion of the Pacific Northwest, with drainage basins spanning portions of seven U.S. states and British Columbia, in Canada. Historically, the Columbia and Snake Rivers provided unobstructed, optimal, and pristine habitat for the wild salmon and steelhead returning to spawn. Today, man-made pressures, dams, and environmental challenges have pushed wild salmon and steelhead populations to the brink, with the Federal Government currently listing 12 of the 13 salmon populations found in this river system as being “high risk” for extinction.

With the precipitous decline of salmon in the Columbia-Snake River system comes the compounded effects of decreased food availability for the Southern Resident orcas who have relied especially on the Chinook that enter the Columbia-Snake in the spring. The winter/spring period is an especially critical time for Southern Residents, with Chinook salmon typically less available, naturally, during this lean time. Continuing to reduce what winter/spring resources are available has contributed to the overall continued decline of their population.

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The Chehalis River is the second largest river in Washington State and one of the only remaining free flowing major rivers on the west coast.

It is one of the biggest producers of wild (non-hatchery) salmon in the state. It contains 31 salmonid stocks, and supports spawning of wild spring Chinook, fall Chinook, Coho, and Steelhead. None of the salmon stocks are currently listed as threatened or endangered under the U.S. Endangered Species Act, however salmon in the Chehalis Basin have seriously declined 50 to 80% due to overfishing, unregulated timber harvest, and habitat destruction. It is estimated that the Basin’s spring run Chinook could be functionally extinct by the end of the century unless action is taken.

Chinook salmon from the Chehalis River are part of the Washington Coast stock which is listed as a priority stock for the endangered Southern Resident orcas, and satellite tagging has shown that Southern Resident orcas feed off Grays Harbor where the Chehalis River enters the Pacific Ocean.

Due to frequent and sometimes catastrophic flooding in the region, the Chehalis Basin Board is proposing the construction of a “flood retention facility” (dam) to mitigate the effects of floods.

The proposed dam would drown 6 miles of critical salmon and steelhead habitat, result in increased temperature and decreased dissolved oxygen and would permanently eliminate many acres of habitat. It would only protect a small percentage of homes and businesses in the Chehalis Basin, primarily those located along the I-5 corridor. The proposed project requires both state and federal permits, and both of those processes are currently underway. Out of concern for the impacts this dam would have on the river, salmon, local tribes, and Southern Resident orcas, a coalition of concerned citizens, Tribes, and local organizations formed the Chehalis River Alliance.

In July 2020, Governor Inslee expressed concern about the construction of a dam and directed the Chehalis Basin Board to work with local tribes to develop non-dam alternatives. As a result, the LAND (Local Actions Non-Dam) Steering Committee is currently meeting to develop sustainable flood reduction projects in the Chehalis Basin.

Action Item:

Here is how you can help stop the construction of the Chehalis River flood retention facility:

· Learn more about the Chehalis Basin and the proposed dam at

· Watch the documentary Chehalis: A Watershed Moment on Amazon Prime

· Contact your local Washington legislators, and Governor Inslee’s office and let them know that you oppose the construction of a dam on the Chehalis River, and that you support local non-dam alternatives that will mitigate flooding while protecting and restoring important salmon habitat.

o Contact your legislator: Legislative Information Center Contacting Your Legislators (

o Contact Governor Inslee’s office: Contacting the Governor | Governor Jay Inslee (


· Chehalis Basin Strategy Fish and Wildlife Fact Sheet

· Proposed Chehalis River Basin Flood Damage Reduction Project, 2020



· Northwest Fisheries Science Center satellite tagging blog

This week, we travel out of the Salish Sea into the Pacific Ocean to explore some important habitat in the coastal waters off British Columbia and Washington.

Swiftsure Bank is an area of rich, productive water off the coast of Vancouver Island. It is located about 15 miles west of the entrance to the Strait of Juan de Fuca, where deep submarine canyons meet the continental shelf. As currents rise from the canyons they bring cold nutrient-rich waters to the shallow bank. This upwelling becomes the basis for plankton which in turn supports a diverse ecosystem that includes many species of fish. Many salmon migrate through Swiftsure Bank on their way to the Salish Sea, making it an important foraging area for resident orcas, and acoustic data has shown that Southern Residents are present there in all months of the year.

In 2018, Canada added Swiftsure Bank to Southern Resident orca critical habitat, which is defined as "the habitat that is necessary for the survival or recovery of a listed wildlife species.” In recent years, J, K, and L Pods have been spending more time at Swiftsure Bank during the summer months, and fewer days in their core summer habitat around the San Juan and Gulf Islands as Fraser River Chinook has continued to decline. Many people believe that these inland waters are important to the Southern Residents not just as a traditional source of prey, but for cultural reasons as well, and that their decreased presence here may have long term effects on their social structure and culture. While their absence is keenly felt, the fact that they are foraging at Swiftsure Bank during the summer, and seemingly finding abundant food is a comfort. Hopefully this prey source will continue to sustain them until we can restore the Salish Sea salmon runs to a level that will allow Southern Residents to thrive here once again.

Further south, off the coast of Washington several rivers and streams flow from the Olympic mountains to the Pacific Coast. Salmon runs in these rivers are currently relatively stable and while a number of spring Chinook runs on the west coast are in decline, they still have a good chance of recovery with robust restoration efforts. In a 2018 report by NOAA Fisheries and Washington Department of Fish and Wildlife, the Washington Coast stock was listed a priority Chinook stock for Southern Resident orcas. This stock includes Chinook salmon from the Hoh, Queets, Quillayute, and Chehalis Rivers, as well as additional small rivers that flow into Grays Harbor.

To determine priority stocks, the report looked at three evaluation factors, including: observed part of Southern Resident diet; salmon consumed during reduced body condition or diversified diet; and spatio-temporal overlap between Chinook salmon and Southern Residents. The purpose of the report was to ”identify Chinook salmon stocks that are important to Southern Resident killer whales (SRKW) to assist in prioritizing actions to increase critical prey for the whales.” Combined with additional research, this report could be an effective tool to determine where restoration and protection efforts might be most beneficial at increasing prey for the Southern Resident orcas.


Riera, 2012. Patterns of seasonal occurrence of sympatric killer whale lineages in waters off Southern Vancouver Island and Washington State, as determined by passive acoustic monitoring

Southern Resident Killer Whale Priority Chinook Stocks Report 2018.

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