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Klamath River: Biggest Dam Removal In History Reaches Final Stages

The Klamath River is unparalleled on the West Coast for its combination of wild and free-flowing stretches, intact forests and marshes, surviving native fish populations, and spectacular recreational activities. (Photo: Western Rivers Conservancy)

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By Akerele Christabel

September 23, 2024
3:25 pm
Los Angeles, CA

Klamath River to receive “new life” after a century of coping with dams Despite their multifaceted advantages to mankind, dams could prove to be environmental hazards, especially after they might have outlived their usefulness. Many dams that were once at the epicenter of a community’s livelihood are now old, unsafe or no longer serving their intended purpose. Instead, they now have negative effects on the ecosystem. Due to dams blocking up flowing bodies of water, such as rivers, animals that depend on the flow to reproduce or as part of their life cycle are put in danger. Migratory fish that mate in a very completely different location than they live the rest of their lives, for instance, are unable to mate and may decline in population. The build-up of

Klamath River to receive “new life” after a century of coping with dams

Klamath River Basin (Photo: fisheries.noaa.gov)

Despite their multifaceted advantages to mankind, dams could prove to be environmental hazards, especially after they might have outlived their usefulness. Many dams that were once at the epicenter of a community’s livelihood are now old, unsafe or no longer serving their intended purpose. Instead, they now have negative effects on the ecosystem.

Due to dams blocking up flowing bodies of water, such as rivers, animals that depend on the flow to reproduce or as part of their life cycle are put in danger. Migratory fish that mate in a very completely different location than they live the rest of their lives, for instance, are unable to mate and may decline in population. The build-up of water is additionally dangerous for flowers that grow on the natural boundary of the water. The plant life may get submerged and die.

Dams change the way rivers function. They can trap sediment, burying rock riverbeds where fish spawn. Gravel, logs, and other important food and habitat features can also become trapped behind dams. This negatively affects the creation and maintenance of more complex habitat (e.g., riffles, pools) downstream. Dams that divert water for power and other uses also remove water needed for healthy in-stream ecosystems. Peaking power operations can cause dramatic changes in reservoir water levels. This can leave stretches below dams completely de-watered.

Klamath River: A Case Study of River Preservation

Dam removals in the United States were few and far between until the mid-1970s when environmental awareness became more mainstream and the impacts of dams were more widely know. Once it emerged on the scene, dam removal continued to gain momentum for the next 25 years, while dam construction saw a plunge across the United States.

Since 2000 the number of dams removed has been greater each year than the number of dams constructed. Coupled with increased knowledge of the ill effects of dams combined with continued concerns about their aging infrastructure and costs to maintain them, interest in dam removals continues to increase. The increased interest in dam removals has been further amplified through highly publicized dam removals such as those on the Elwha River in Washington, U.S.

Presently, the Klamath River dam removal has received a lot of attention from the media as it is set to go down as the biggest dam removal in history.

The Klamath Basin covers over 12,000 square miles (31,000 sq km) in southern Oregon and Northern California. It was home to the JC Boyle, Copco 1, Copco 2 and Iron Gate dams, which are all owned by the electric utilities company, PacifiCorp. The Klamath has the reputation of being the third-largest salmon producing river on the United States’ West Coast. This remained true until the construction of the dams blocked fish from acessing close to 400 miles (640km) of critical river habitat for more than 100 years.

It’s hoped that salmon numbers in the Klamath will improve significantly as the river runs freer (Photo:BBC/ Lucy Sherriff)

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. Moreover, 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.

In 2022, approval was finally granted to remove the dams, 12 years after the original agreement to pave the way for the project was signed in 2010. Oregon and California agreed to shoulder joint liability and in October 2023, the first dam came down.

On August 28, 2024 crews broke the final cofferdams at the Iron Gate and Copco No. 1 dams. The Klamath River now flows freely from Lake Ewauna out to the Pacific Ocean. This was a major milestone, marking the end of a significant construction phase in the largest salmon restoration project ever undertaken in the United States. As with the initial breach of the dams, removing the cofferdams created a temporary drop in water quality as sediments starved of oxygen moved downstream. Water quality is steadily improving as the river continually flows and sediment is flushed downstream. By 2061, it is estimated that the chinook salmon population will have recovered by an average of 81%.