Oregon Tore Down Three Dams — What the Salmon Did Next Shocked Scientists

Picture this. It's October 2024, somewhere along the Oregon-California border. A scientist is staring at a sonar monitor in the dark. The screen flickers, then a shape, then another, then dozens more swimming hard upstream through water they have never touched in their entire lives. Water their ancestors last swam over a century ago. The scientist picks up her radio. She can barely get the words out. The salmon are back. A year after the Klamath River was returned to its free-flowing state by way of the world's largest ever dam removal project, scientists say nature has rebounded in astounding ways. But to understand just how extraordinary that moment was, and why it matters for every river in America, you have to go back to the beginning. Back to when the Klamath was dying, the Klamath River was once the third most abundant salmon-producing river on the west coast of the lower 48 states. For millennia, six federally recognized Native American tribes lived on the bounty provided by the Klamath River and its forests and surrounding grasslands. Salmon and abundant aquatic life nourished these communities and their spiritual practices, establishing these resources as central to their identity and existence. Then came the dams. In 1918, the first dam in the Klamath Hydroelectric Project, COPCO-1, became operational, ending salmon runs in the upper Klamath Basin. More followed. The dams, completed between 1918 and 1962, significantly altered the river's natural flow for more than a century, preventing threatened and endangered salmon and steelhead trout from reaching their spawning grounds. The reservoirs those dams created didn't just block fish, they cooked the river. When the dams were present, water collected heat over the summer, resulting in hot water temperatures that lasted far longer than they typically would. Stagnant, warm, oxygen-poor water became a breeding ground for toxic algae. In 2006, the Karuk tribe reported blooms of toxic algae in reservoirs exceeding World Health Organization guidelines by nearly four Since COPCO-1's construction in 1918, salmon populations had plummeted, eliminating two salmon species and bringing other salmon populations to just five percent of their historic averages. Think about that number. Five percent. A river that once teemed with life, reduced to a ghost of itself, and the communities who depended on it, reduced along with it. The breaking point came in the summer of 2002. Drought had gripped the region. Farmers were diverting more water than scientists recommended, and then, over eight days in September, more than 60 Hohenzollern's dead adult Chinook salmon floated to the surface of the lower Klamath, sparking widespread despair, anger, and an urgent call to action. Imagine standing on those banks. The smell. The silence where there should have been rushing water and leaping fish. For tribal members who had fished these waters for generations, it was devastating beyond words. For tribal communities, it was a moment of both unbearable grief and renewed resolve. That resolve carried through generations and is now transforming the river itself. The fight to remove the four lower Klamath dams began in earnest in the early 2000s, led by the Yurok, Karuk, and Klamath tribes. After the 2002 fish kill made national news, the campaign to remove the dams grew beyond a local issue into a national movement supported by environmental NGOs and pro-fishing groups in California and beyond. It took two more decades of legal battles, negotiations, protests, and political maneuvering, but eventually the coalition held. After more than 20 years of tribal-led advocacy with the support of a broad coalition of conservation and commercial fisheries organizations, four dams along the Klamath River were slated for removal, the largest river restoration and dam removal project in U.S. history. Now here's where this story shifts from tragedy to something that will genuinely take your breath away. Topco No. 2 was fully removed in October 2023, marking the first of four dam removals along the Klamath River. Then, in January 2024, crews began draining the remaining reservoirs. The four Klamath dams ranged in height from 33 feet to 172 feet and had blocked fish passage to more than 400 miles of the Klamath River. Iron Gate Dam, the lowest on the river, the one that had been the final wall between the ocean and hundreds of miles of spawning habitat, began coming down in May 2024. Excavators took massive bites out of concrete that had stood for generations. By late August, crews broke the final cofferdams at the Iron Gate and Topco No. 1 dams and the Klamath River flowed freely from Lake Iwana out to the Pacific Ocean. The largest river restoration project in American history had officially completed all of the work to remove the dams ahead of schedule and on budget. Now here's the part nobody fully predicted. Within 10 days of completing the final in-water work at Iron Gate Dam, more than six otocellar chinook salmon were observed migrating upstream into newly accessible habitat over a two-week period. Ten days. The concrete wasn't even cold yet and the fish were already moving. Just over two weeks after the cofferdam was opened, a crew spotted a pair of salmon spawning in one of the tributaries above Iron Gate where the fish had not previously been able to reach. Then came the moment that made researchers stop and stare. On October 16th, biologists spotted fall chinook salmon at the mouth of a tributary in Oregon, 230 miles from the ocean above all four of the former dam sites. With the construction of the dams, salmon had been absent from the upper basin for over 100 years and now they were back, not in years, not after a decade of careful rehabilitation, in weeks. As Damon Goodman, Mount Shasta-Klamath Regional Director for California Trout, put it, the rivers seemed to come alive almost instantly after dam removal and fish returned in greater numbers than I expected and maybe anyone expected. The monitoring effort that captured all of this was extraordinary in its own right. A coalition of 19-plus partners including California Trout, the Karuk Tribe, Yurok Tribe, the Klamath Tribes, Oregon and California Fish and Wildlife Agencies, university researchers, and non-profits powered one of the most comprehensive salmon monitoring programs in the West. The team used a combination of methods including sonar enhanced by AI, tangle netting, PIT tags, radio telemetry, and spawner surveys to follow the fish. They installed cameras that used sound waves to generate movie-like imagery of passing fish continuous around the clock. According to Goodman, the fish monitoring effort done by California Trout is likely the most comprehensive science and monitoring project ever done to evaluate a dam removal effort. What did that monitoring find? Between October and December 2024, 700 fish passed through the former Iron Gate Dam site with an average of 588 fish per day with Chinook salmon making up about 96 percent of the fish that made their way upstream and then in fall 2025 the numbers jumped again. More than 10 fish over two feet long likely Chinook salmon passed the former Iron Gate Dam site substantially more than in 2024. Fish returned weeks earlier in 2025 when compared to 2024. Year over year the recovery is accelerating with salmon swimming upstream, bald eagles flying overhead, and bear, beaver, otter, and osprey activity. The ecosystem is booming with ecological shifts. This is what scientists call a trophic cascade. When one species returns it pulls the rest of the web back with it. The river doesn't just get its fish back, it gets its birds, its mammals, its insects, its plants. It gets its entire identity back. Water quality has transformed too. The Karuk tribe's fisheries program manager reported that water quality has increased in the Klamath River due to sediments settling from the dam removal and water temperatures naturally regulating. The toxic algae blooms that once exceeded safety thresholds by thousands of times are fading. The river is quite literally cleaning itself. Barry McCovey Jr., director of the Yurok Tribal Fisheries Department said, the speed and scale of the river's recovery has exceeded our expectations and even the most optimistic scientific modeling proving that when the barriers fall nature has an incredible power to heal itself and the restoration work on land is just beginning. The Klamath River Renewal Corporation has accumulated on the order of 19 billion seeds from 98 native species of plants, shrubs, and trees to plant in the areas formerly submerged by the reservoirs. Work will continue for several years restoring the two 200 acres of formerly submerged lands. Helicopters ferrying in trees, tribal crews planting seeds by hand. A landscape that was a reservoir floor is becoming a meadow then a forest reaching toward what it once was. Experts expect Coho salmon populations to recover in 6 to 12 years and Chinook salmon in 15 to 20 years in what was once the third largest salmon producing river in the contiguous United States. Now here's the question that matters beyond the Klamath. What does this mean for the rest of America? The Klamath effort joins more than two dam removals that have been completed in the United States but none like this. Never before have four dams of this size and scale been removed simultaneously noted Brian Graber, Senior Director of Dam Removal Strategy at American Rivers. The removal of these dams on the Klamath River will reopen more habitat to Pacific salmon than all previous dam removals in the west combined. That is not a small claim that is a seismic shift in what we know is possible. The success is also galvanizing momentum for dam breaching and ecological restoration on other rivers including the Snake River in the Pacific Northwest. In Oregon and Washington where the Snake River feeds into the Columbia there is a growing movement calling for the removal of four problematic dams again to save the salmon. The Klamath is no longer just a river story. It is a proof of concept. It is evidence gathered by scientists and tribes and cameras and sonar that a century of damage does not have to be permanent. There is something almost impossible to put into words about what happened on the Klamath. A fish that navigates by the magnetic field of the earth that finds its way back to the exact stream where it was born that fights upstream for hundreds of miles that fish denied its path for over a hundred years found the door the moment it was opened. It didn't wait for an invitation. It didn't need a recovery plan or a release. It just swam home. As Mark Branson CEO of the Klamath River Renewal Corporation put it without the work of the tribes to point out the damage that these dams were doing not only to the environment but to the social and cultural fabric of these tribal nations there would be no dam removal. This is a victory that was earned over decades by people who refused to give up on a river when almost everyone else had written it off. The Klamath is not fully healed. The work continues but in the fall of 2024 something happened in those cold clear waters that scientists are still processing. Nature given even a fraction of a chance came roaring back faster than anyone thought possible and that changes everything we thought we knew about what rivers and the people who fight for them are capable of. If this story moved you share it with someone who needs to hear it and if you want to see more stories about the moments where the natural world surprises us where the science is jaw-dropping and the stakes are real hit subscribe. There are more rivers out there waiting for their moment and we're going to cover every one of them.