Anything that can be built can be taken down': The largest dam removal in US history is complete – what happens next?
«The Klamath River is free of four huge dams for the first time in generations. But for the Yurok tribe, the river’s restoration is only just beginning – starting with 18 billion seeds.
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The Klamath Basin covers more than 12,000 square miles (31,000 sq km) in southern Oregon and northern California, and was home to the JC Boyle, Copco 1, Copco 2 and Iron Gate dams, all owned by PacifiCorp, an electric utilities company. The Klamath was once the third-largest salmon producing river on the US’s West Coast before the construction of the dams blocked fish from accessing almost 400 miles (640km) of critical river habitat for almost 100 years.
Fall chinook salmon numbers plummeted by more than 90% and spring chinook by 98%. Steelhead trout, coho salmon and Pacific lamprey numbers also saw drastic declines, and the Klamath tribes in the upper basin have been without their salmon fishery for a century, since the completion of Copco 1 in 1922. The situation became so bad that Yurok tribe – who are known as the salmon people – began importing Alaskan salmon for their annual salmon festival, traditionally held to celebrate the first return of fall chinook salmon to the Klamath River.
The dams also had a severe impact on water temperature and quality – growth of toxic algae behind two of the dams resulted in health warnings against water contact.
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Restoring the land
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Between 2018 and 2021 seed collection crews – many of whom are tribal elders – were hired to harvest native seeds, by hand, in preparation for the dam removal. They collected 98 species and around 2,000lbs (900kg) of seeds.
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A total of 18 billion native seeds were propagated – more than 66,000lbs (30,000kg) worth – each species selected for a purpose: to retain sediment, to prepare the soil for other plants, for cultural uses, or to be a food source. Wheatgrass, yarrow, lupine and oak trees – an important cultural species for the Yuroks and a keystone species – to name a few.
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The most important part about restoration is ensuring a high diversity, says Chenoweth, who had previously worked on the Elwha River dam restoration, which was demolished in 2014. “Most restoration projects are lucky to have six to eight species. We have as many as 22 species in our seed mixes.”
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After planting is completed, the area will be monitored and maintained for five years by Resource Environmental Solutions. There are four success criteria set out by the restoration plan that need to be met in order for the project to be considered successful: species richness, vegetation cover, scarcity of invasive species and stem count – applicable for forest areas.»