Hydropower
Hydropower dams in Washington provide affordable, reliable power for the rest of the Pacific Northwest without polluting air or contributing to climate change. This power does have an environmental cost though. Washington has more than 1,345 dams, including about 145 large power-generating dams owned or regulated by the federal government. Hydropower dams block large areas of former salmon habitat, particularly in the Columbia River and its tributaries, where thousands of miles of habitat are blocked in the upper Columba and Snake Rivers and their tributaries.
Dams also interrupt natural river processes, changing the flow of the water and the way water moves logs and gravel throughout river systems, all of which are essential for creating and maintaining salmon habitat. They also block salmon migration and create slack-water areas favored by animals that eat salmon.
PRESSURE: Fish Passage
Most hydropower dams in Washington allow adult fish to pass upstream and juvenile fish to pass downstream of the dam, using fish ladders or bypasses. Sometimes, dam operators trap and haul fish by truck or barge around the dams. These methods have had varied success; adult salmon generally can migrate successfully through fish ladders, but traps in reservoirs often cannot catch enough young fish. When these systems don’t work well, fewer adult salmon return to their natal streams, and populations dwindle.
Fish ladders, pictured below, are a series of gradual steps that enable fish to swim around or over a dam. Ladders are in place at all federal projects on the lower Columbia and lower Snake Rivers.
Fish ladders cannot work at very high dams, such as Grand Coulee Dam, because there is not enough space to create stair-steps for fish and the water behind the dams frequently changes in height. Also, collecting juvenile fish above these dams is challenging technically. While most large hydropower dams in Washington use fish passage technology to allow fish to pass the dam, many high dams do not. These dams continue to block large areas of potential habitat for salmon and steelhead.
PROGRESS AND PRIORITIES
In 2023, the federal government pledged full funding, estimated at $300 million, to work with upper Columbia basin Tribes to complete the second phase of reintroducing salmon above Chief Joseph and Grand Coulee Dams. Blocked to salmon since the 1930s, more than one thousand miles of river will be home to salmon once again.
Fish passage technologies have improved, and salmon reintroduction efforts are underway in many watersheds that have been inaccessible for nearly one hundred years, such as the upper Lewis, Cowlitz, and Green Rivers, and the Columbia River above Grand Coulee Dam. In some areas, such as the Elwha, Middle Fork Nooksack, Pilchuck, and White Salmon Rivers, dams have been removed, greatly benefiting salmon.
Hydropower managers recently have changed how much water is directed over dams in the Columbia and Snake Rivers, rather than through electricity-generating turbines, to benefit salmon. Known as spill, these flows have sped juvenile migration to the ocean and increased their survival by avoiding turbines.
PRESSURE: Systemic Effects
Dams interrupt river systems: they slow and often warm water in reservoirs, block gravel and large wood from flowing downstream, disrupt beneficial floods, and inundate spawning and rearing habitat. Reservoirs and slack-water habitat formed upstream of dams and migration bottlenecks below dams provide ambush areas for predators, including birds, fish, and marine mammals. The lower Snake River dams have received increased scrutiny in recent decades as their impacts on salmon and steelhead have become clearer. These problems are interrelated and require complex, comprehensive solutions.
PROGRESS AND PRIORITIES
Several recent efforts have focused on restoring salmon and steelhead affected by dams across Washington.
On the Cle Elum River in Kittitas County, the federal Bureau of Reclamation, Washington Department of Ecology, Washington Department of Fish and Wildlife, and the Confederated Tribes and Bands of the Yakama Nation worked together to create an innovative solution to getting juvenile salmon past Cle Elum Dam. The Yakama Nation has reintroduced sockeye in the river, but downstream passage is a challenge at this high dam. A facility, completed in summer 2024, collects young fish from the reservoir regardless of water levels and then sends them through a spiraled structure that works much like a waterslide, preventing injury and speeding downstream migration. This is one of the most ambitious actions in the Yakima Basin Integrated Plan, a comprehensive approach to preserving water, agricultural lands, fish, and other wildlife.
Meanwhile, on the Green River southeast of Seattle, the U.S. Army Corps of Engineers is building downstream juvenile fish passage facilities at Howard A. Hanson Dam. Coupled with a Tacoma Public Utilities facility to transport adult fish upstream of the dam, the project will reconnect salmon with more than one hundred miles of river and streams above the dam. The upper Green River watershed is protected as a drinking water source for Tacoma and other communities, ensuring healthy, long-term habitat for salmon.
Also in 2024, the federal government reached agreement with the Nez Perce Tribe, the Yakama Nation, the Confederated Tribes of the Warm Springs Reservation of Oregon, the Confederated Tribes of the Umatilla Indian Reservation, the State of Oregon, and the State of Washington to pause litigation over operation of the Federal Columbia River Power System, which includes thirty-one hydroelectric projects on the Columbia River and its tributaries. This agreement includes historic investments by the federal government to comprehensively restore Columbia River basin salmon to healthy and abundant levels, honor federal commitments to Tribes, deliver affordable and reliable clean power, and meet the many needs of interest groups across the region.
Banner photograph of Ross Dam in Whatcom County courtesy of the U.S. Army Corps of Engineers
Photograph of the John Day Dam by Karim Delcado