HORNBROOK, Calif.-In August, crews completed the largest dam removal project in US history by demolishing the last of the four dams on the Klamath River. For decades, tribal nations on the Oregon-California border have fought to restore the river back to its natural state. For the past 100 years, the four hydroelectric dams on the Klamath River-Iron Gate Dam, Copco Dams 1 and 2, and JC Boyle Dam-have prevented the region's iconic salmon population from swimming freely along the Klamath River and its tributaries.
As the dams blocked the water, they caused millions of tons of sediment, which harmed the river, water quality, and federally protected species. Manmade dams, warm water and prolonged droughts have profoundly altered the river and the ecosystems that rely on it. And in the process, the salmon population was nearly destroyed.
The utility company PacifiCorps built the dams in the early to mid-1900s, without tribal consent, to generate electricity for parts of the growing West. But the dams severely disrupted the lifecycle of the salmon, blocking the fish from accessing their historic spawning grounds. Salmon begin their lives in freshwater systems, like the Klamath River, then travel to the ocean and back again to their spawning grounds. Dammed rivers prevented their ability to reach the spawning grounds.
Julie Alexander of Oregon State University told CNN reporters that dam installations alter the flow regime of rivers, which changes the water's temperatures since reservoirs act as thermal units that get warm in the summer.
"This tends to exacerbate pathogens and concentrates the fish so they're more on top of each other, so you have directly transmitted parasites that can kind of jump from fish to fish," she said.
Besides the spread of viruses, warm water and drought-fueled water shortages in the Klamath River also killed salmon eggs and young fish due to low oxygen and lack of food.
In 2002, a viral outbreak due to warm temperatures and low water killed more than 34,000 fish species, primarily the chinook salmon on the Klamath River.
And this affected the tribes in the region.
For thousands of years, the Klamath River underpinned the physical well-being and cultural identity of native tribes. The Klamath was once the third-largest salmon producing river on the west coast and teemed with salmon and trout.
When the first salmon of the season was spotted in Yurok country, a runner was sent upstream to let the next village know it was time to get ready, and so on up into the Upper Basin. Each community worked as a team to construct temporary fish weirs for harvesting fish, but fishing could not begin until ceremonies were performed and enough fish had passed upsteam to spawn and create the next generation of salmon.
As the river's health declined over several decades, citizens of the Klamath Basin challenged each other in courtrooms to protect their families, communities, environment and ways of life.
Hardship and conflict escalated in 2001, when the government cut water deliveries to farms to protect endangered fish. The major loss of juvenile salmon in 2002 later resulted in widespread and costly in-river and ocean salmon fisheries closures.
The Yurok, and other area tribes whose lives and cultures have revolved around the salmon, began to push for the dams to be removed. And leaders with different interests in the river began working together on solutions to restore river health, as well as address many broader stakeholder concerns. Rather than restructure dams to be more environmentally friendly, PacifiCorp agreed to remove the dams, which, at full capacity, produced less than 2 percent of PacifiCorp's energy.
Federal regulators approved the plan to raze the dams in 2022. The next year, the smallest of the four dams, Copco No. 2, was removed. Crews then began releasing water from the dams' reservoirs at the beginning of this year, which was necessary before dismantling the last remaining dams. And now, the final dam has been taken down.
"The river for Yurok has always been our lifeblood," Amy Bowers-Cordalis, a member and general counsel for the Yurok Tribe, told CNN. Unlike her tribe's elders, she couldn't catch as many fish growing up and would see fish carcasses rotting on the banks. "So, restoring the river enables future generations to have a shot at continuing the Yurok fishing way of life."
Mark Bransom, chief executive officer of the Klamath River Renewal Corporation, the nonprofit group created to oversee the project, told CNN. "For the first time in over 100 years, the river is now back in its historical channel, and I think that was an extraordinarily profound moment for people to actually witness that-the reconnecting of a river."
Built-up sediments stored behind the dam for over a century, potentially containing high levels of organic material, have been released, transforming the river into muddy brown water and harming some of the wildlife in and around it.
But Bransom and others have described this as "short term pain for long-term gain."
The worst water quality conditions have likely passed as the initial backup of sediment has been flushed downstream. Water quality is seeing steady improvements; as the river begins to heal, the removal of the dams will improve water quality, from nutrients to dissolved oxygen and stream temperature, and reduce the likelihood of toxic algae blooms, creating healthier habitat for salmon, other fish and wildlife, and people.
Other case studies of removed dams have shown that the areas recover quickly. When the Condit Dam on the White Salmon River was removed, 60 percent of the sediment was eroded through natural processes within 15 weeks, and native fish were found above the former dam locations within a year of the removal. When Bloede Dam was removed in 2018, 50 percent of the sediment eroded away within 6 months of removal, with native fish populations making a similar rebound.
The Klamath River Renewal Corporation has seen victory, but that doesn't mean the work is over. They plan to put down nearly 16 billion seeds of almost 100 native species across 2,200 acres of land in the Klamath River Basin.
