Science Friday

The Story Behind The Largest Dam Removal In U.S. History

October 9, 2025

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  • The 2002 massive salmon die-off on the Klamath River, attributed to poor water management, served as a critical catalyst for Amy Bowers Cordalis and Barry McCovey Jr., and the broader Yurok Nation, to dedicate their careers to fighting for river restoration and dam removal. 
  • The economic argument for dam removal ultimately succeeded because maintaining the aging hydroelectric dams to comply with federal law (like installing fish ladders) was more expensive for the power company, PacifiCorp, than removing them. 
  • The immediate aftermath of the final dam removal saw Chinook salmon quickly migrating past the former dam sites and spawning in streams that had been inaccessible for a century, demonstrating the river's rapid capacity for healing when treated as a relative rather than just a resource. 

Segments

Introduction to Dam Removal
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(00:01:21)
  • Key Takeaway: The Klamath River dam removal is the largest such project in U.S. history, aiming to restore a river that previously supported a top salmon run.
  • Summary: The episode focuses on the largest dam removal project in U.S. history concerning the Klamath River. Hydroelectric dams installed about 100 years ago caused salmon populations to decline significantly. The restoration effort was led by a coalition including members of the Yurok Nation.
Catalyst for Action: Fish Kill
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(00:02:55)
  • Key Takeaway: The 2002 massive fish kill on the lower Klamath River, resulting in 30,000 to 70,000 dead salmon due to water mismanagement, profoundly redirected the career paths of the guests.
  • Summary: Amy Bowers Cordalis witnessed the 2002 fish kill, which she described as looking and smelling like a war zone, motivating her to attend law school to prevent future ecological disasters. Barry McCovey Jr. was also working as a fisheries technician at the time and was involved in surveying the dead fish. This event galvanized Indigenous peoples and allies to fight for the river’s preservation.
Indigenous Duty and Ecocide
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(00:05:19)
  • Key Takeaway: For the Yurok Nation, stewardship of the Klamath River and its salmon runs is a fundamental duty rooted in creation stories, making the 2002 fish kill a direct threat to their existence and sovereignty.
  • Summary: Amy Bowers Cordalis explained that her family’s generations-long fight is tied to the Yurok duty to live in balance with the natural world. The water diversions leading to the fish kill were viewed as an act of ecocide against the Yurok people. This realization launched a new generation into the fight to preserve their way of life, leading toward dam removal.
Impact of Dams on Salmon
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(00:07:44)
  • Key Takeaway: Dams primarily destroy salmon populations by blocking access to hundreds of miles of upstream spawning habitat and degrading water quality through stagnant reservoirs that create warmer, low-oxygen water and foster toxic algae.
  • Summary: Barry McCovey Jr. detailed that the dams blocked salmon migration, cutting off habitat used for millions of years, causing fish populations to crash. Reservoirs created by the dams lead to poor water quality when released downstream, negatively affecting fish and other aquatic life. This contrasts sharply with the river’s previous free-flowing state.
Negotiation Turning Point
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(00:09:15)
  • Key Takeaway: A pivotal moment in securing dam removal involved Yurok leadership taking PacifiCorp’s parent company executives to the spiritually significant Blue Creek tributary, compelling them to witness the river’s importance firsthand.
  • Summary: When FERC issued an order inconsistent with the settlement agreement in 2020, PacifiCorp threatened to withdraw from the deal. The Yurok leadership invited Berkshire Hathaway executives to Blue Creek, a salmon sanctuary, to let the river speak for itself. Following this visit and the presentation of a term sheet, an executive called back confirming their commitment to removal.
Economic Rationale for Removal
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(00:12:32)
  • Key Takeaway: The power companies were amenable to dam removal because the dams provided minimal energy, were old, non-compliant with federal law, and the cost to upgrade them exceeded the cost of removal.
  • Summary: The four Klamath dams provided only a minimal percentage of PacifiCorp Power’s energy portfolio and required significant investment to meet safety standards, such as installing fish ladders. An economic analysis showed that removing the dams was cheaper than renewing the license and bringing the structures into compliance. This created an economic incentive for dam removal, leading to a settlement agreement initially valued at $450 million.
Immediate Ecological Recovery
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(00:17:06)
  • Key Takeaway: Within weeks of the fourth dam’s removal, thousands of Chinook salmon were observed migrating past the former site and spawning in streams that had been blocked for up to 100 years.
  • Summary: Barry McCovey Jr. reported seeing Chinook salmon migrate past the former dam site just one week after the final removal, with thousands following in subsequent weeks. He personally witnessed fish spawning in streams that had been inaccessible for decades. The river now feels fiercer, stronger, and more vibrant, with cleaner, colder water where the bottom is visible.
Long-Term Monitoring and Lessons
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(00:19:29)
  • Key Takeaway: The Klamath River dam removal is being tracked as the largest river restoration project in history, focusing on the recolonization of fish and aquatic invertebrates, with hopes that its lessons can be applied to future dam removals.
  • Summary: Hundreds of people from various agencies, tribes, and universities are studying the ecological response, tracking fish recolonization, aquatic invertebrates, and water quality. The primary takeaway is that major ecosystem restoration is possible through sustained effort, though decades of work remain to fully heal the ecosystem. The Earth remembers how to heal itself when humans interact with it as a relative.