Lower Snake River Dams

The four federal dams on the lower Snake River provide clean, renewable energy to meet Northwest power needs, stabilize the region’s transmission system, and fight climate change. Despite some statements indicating that they are easily replaced, the facts show that they are invaluable to our region.

How much power do the lower Snake River dams produce?

The lower Snake River dams account for over 10% of the federal system energy supply and generate enough electricity—on average—to annually power a city the size of Seattle. They also help in dealing with power emergencies, such as regional shortages due to extreme weather conditions. The four dams can power roughly two million homes during heat waves or cold snaps.

Up to one quarter of BPA’s operating reserves are provided by the lower Snake River dams. Reserves are the additional capacity that utilities are required to hold in case of unexpected changes in generation or electrical demand. BPA is required to hold these reserves to ensure the reliability of the grid and to balance other renewable resources, like wind and solar power.

What additional benefits do they provide?

Ice Harbor Dam (and its interaction with the McNary Dam reservoir downstream) provides a crucial source of drinking water for Tri-Cities communities. It also enables irrigation for 60,000 acres of farmland in Central and Southeastern Washington. Agriculture would be significantly harmed, and communities would face more severe drought conditions without these dams.

Due to transmission constraints throughout the region, the lower Snake River dams provide a critical local source of reliable power and voltage for this part of the state.

Could the lower Snake River dams be replaced with another clean energy source?

Given today’s commercial technology, some of the most likely replacements for the generating capabilities of the lower Snake River dams—including their 24/7 ability to respond when needed—would be carbon-emitting power plants. In a 2016 assessment, the Bonneville Power Administration estimated that replacing the lower Snake dams with highly efficient natural gas generation would increase the region’s carbon dioxide emissions between two and 2.6 million metric tons annually. That number is the equivalent of the emissions of nearly 421,000 cars on the road each year.

What would be the impact of breaching or removing them?

Without the lower Snake River dams, many communities in the Eastern regions of the Pacific Northwest would be worse off. They would lose access to water for drinking and irrigation, as well as reliable power. Losing the lower Snake River dams would have a devastating impact on over 300,000 people who call the area home.

Beyond that, breaching or removing these dams would be a step backwards in achieving the Northwest’s climate goals. As stated above, the only viable replacement would be carbon-emitting. It would also force a major change in the shipping of goods, requiring them to be transported by train and truck instead of by barge. These less efficient methods of shipping mean more carbon and pollution for the Northwest.

Can we help the recovery of salmon and orca whales by removing the lower Snake river dams?F

Intense studies have been and are continuing to be conducted to determine what impact the Snake river dams are having on salmon and orcas. This is partly because after the last federal dam on the Snake River was completed in 1975, adult salmon returns dwindled.

During the same time frame, however, ocean conditions shifted from cooler-than-normal temperatures to warmer-than-normal temperatures. This type of shift has been determined to be a leading indicator of reduced adult salmon returns. There is strong evidence that ocean conditions, including ocean temperatures, form an important predictor of future adult salmon returns as well.

Some believe growing numbers of seals and sea lions, which feed on the fish, are behind the declines as well. Others say the warming and acidifying of the ocean is starting to affect the food web that the salmon depend on.

Thus far, the conclusion that has been reached is that the lower Snake river dams cannot be linked to the declines seen in Snake River salmon and steelhead. Rather, the pattern of decline has been observed in all rivers along the West coast, including free-flowing rivers. By comparison, the Snake River actually boasts some of the best juvenile survival rates, and improvements at the lower Snake river dams have led to conditions that are regarded as better than those in natural, free-flowing rivers.

Meanwhile, a NOAA Fisheries analysis showed that chinook from the Puget Sound—not the Columbia or Snake rivers—are the top priority salmon stock for Southern Resident Killer Whales. Unfortunately, while the Columbia and Snake rivers saw a record number of adult chinook salmon returns this past decade, Puget Sound chinook numbers did not.

Scientists point to a loss of habitat around the Sound and a population explosion of seals and sea lions in the Sound as contributing factors to their struggles. Researches also identified measurable amounts of prescription and illicit drugs and other chemicals found in the Puget Sound’s salmon as causes for concern.

Importantly, NOAA Fisheries found that the hatchery chinook in the Columbia and Snake river basins more than compensate for fish lost as a result of dams in terms of availability for orca whales. However, the resident orcas spend little time feeding in the areas where Columbia and Snake river chinook are present.

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