A year after the landmark removal of four dams on the Klamath River, the ecosystem is showing signs of recovery beyond scientists’ expectations.
The Klamath River flows 257 miles from southern Oregon to the Pacific Ocean in Northern California, spanning a diverse array of habitats that range from arid high desert to coastal temperate rainforest. The river is an important resource not only for the fish and wildlife that depend on it, but also for people. Klamath Basin Tribes have lived on this river for thousands of years, sustained by the clear, cold waters preferred by salmon and other important and culturally significant native species like the endemic suckerfish species and Pacific lamprey. Historically, the Klamath supported the third-largest run of salmon in the West, but human development over the past century has caused significant declines in the river’s health.
Beginning in 1911, the Lower Klamath Hydroelectric Project constructed four dams on the river without tribal consent. Three of the lower dams did not provide fish passage for salmon, resulting in the loss of hundreds of miles of historical spawning and rearing habitat for the species. Furthermore, reservoirs created by all the dams have caused dramatic changes to the ecosystem, which have had a cascading effect on riverine species and the people who depend on them.
Anadromous species, such as salmon, are particularly sensitive to changes caused by dams due to their migratory life cycle. Elleanor Martin, a leader for Whitman’s Salmon Conservation Club, detailed the challenges dams pose to the fish.
“Beyond directly blocking migration, dams change the ecosystem significantly, which can cause increased juvenile mortality and make it harder for adults to survive during migration. This is part of the reason we have seen less and less salmon over the years since these dams were constructed on a large scale,” Martin said.
For many tribal members, the decline in salmon is about more than the loss of a vital food source. Indigenous activism was at the forefront of the decades-long debate over the dams, and the victory and subsequent return of salmon represent a major turning point for Klamath Basin Tribal nations. Amy Bowers Cordalis, a member of the Yurok Tribe and Principal of the Indigenous-led conservation group Ridges to Riffles, shared her view going forward.
“Dam removal is essential for the survival of Indigenous cultures in the Klamath Basin. Their presence in the river is a reminder of the centuries of colonization that have nearly destroyed the lifeblood of my people, the Klamath River. The removal of the dams is a result of the Yurok people’s unwavering commitment to protecting and restoring the river for future generations. It is a sign of hope and healing – we are making real progress toward restoring balance to our environment,” Bowers Cordalis said.
Removing the dams is only the first step in the journey towards healing the Klamath. Since the dams were torn down last year, scientists and researchers have been extensively monitoring the river, collecting data on salmon and other native species as well as indicators of water quality. Monitoring efforts track salmon’s movement and health, and even collect genetic data. So far, the results have been promising, with the salmon and the river showing signs of recovery that exceed expectations.
Improvements in water quality were among the first observable changes following the dam’s deconstruction. Since the four lower Klamath dams were removed in 2024, water quality monitoring efforts by tribes and varying conservation groups have shown rapid improvements, with cooler water temperatures, higher levels of dissolved oxygen needed for aquatic species and a reduced presence of harmful cyanobacteria associated with algae blooms that were once common in the reservoirs’ warm, stagnant waters. Taz Soto, head of the Karuk Tribe’s fisheries department, discussed these changes and their effects on people.
“We’re seeing really instantaneous results. Looking at past samples of the Klamath when the reservoirs were in place, we had harmful algal blooms almost every year. At least during the summer, water quality was well above the public health standards set by the state of California – but since the dam removal, 100% of our samples are below the public health limit. It’s still very early stages, but we’re seeing really great success in the first year,” Soto said.
Soto also remarked on the rapid return of salmon to the basin. Since deconstruction began, salmon have been found migrating past the former dam sites to spawn in the upper Klamath and its tributaries for the first time in over a hundred years.
“We had tempered expectations. We didn’t expect salmon to move as fast and as far as they have already, and it’s exciting to see that kind of data come in in real-time. I think that watching these salmon distribute into the upper Klamath, where they haven’t been for over a hundred years, is very promising, but it does also highlight the need for a lot more work,” Soto said.
There are still two dams in operation on the Klamath: Keno and Link River. Unlike the four decommissioned dams on the lower Klamath, these reservoirs are used for irrigation and flood control, making the prospect of removal more contentious. Soto spoke about the need for infrastructure improvements at these sites, remarking that while fish passage structures are in place and salmon do successfully swim past the dams, improvements are still needed.
Keno and Link River dams were never designed with salmon in mind. As a result, fish passage structures don’t adequately meet the needs of salmon and other native fish species — at Keno, holes in the structure are too small for large-bodied salmon to fit through, leaving the upper Klamath River and its tributaries unreachable. Further complicating the issue, fish passage structures must be altered to accommodate the needs of several species of native fish, all of which hold high cultural significance for the tribes. Scientists point out that the flows out of the fish ladder at Keno are often insufficient to attract migrating fish, such as salmon and Pacific lamprey. However, altering the flow to benefit salmon could be detrimental to two species of native suckerfish that are also culturally important to local tribes. Even if fish do manage to pass through the dams, the ecosystem above the Keno and Link River dams is severely degraded due to the heavy presence of agricultural enterprises in the region.
Beyond infrastructure modifications, local tribes and conservation groups are pushing to improve upland habitat on the newly accessible reaches of the river. Over 400 stream miles of previously unreachable habitat were opened to salmon following the removal of the dams; however, many of these waters remain degraded and in need of restoration before they can support salmon and other wildlife. Ongoing projects involve revegetating riparian areas along the river and efforts to return stream channels to their historic natural flows. These projects have already shown success – just this month, the Yurok tribe hosted a celebration of the completion of restoration projects on four tributaries of the Klamath River.
Environmentalists often cite the success of the Klamath as an example for future dam removal projects nationwide. In the case of the Lower Snake River dams, for example, dam removal is recommended if salmon populations are to be restored to their historic numbers, but logistics prove challenging. The Klamath River’s rapid recovery following dam removal is a promising sign that change is possible.
Elleanor Martin is hopeful about the future of salmon following the removal of the Klamath dams.
“I think a lot of people look at dam removal as something that there are always barriers to, that there are always reasons the dams can’t be removed. Seeing the removal successfully implemented on the Klamath is important because it shows that removal is possible even with these challenges. Seeing that people got out and made this change on the Klamath, and having this successful case to point to, is really encouraging,” Martin said.
For many, the Klamath River is a sign of hope for the future of salmon and our watersheds as threats from climate change loom. It’s also a symbol of the resilience of salmon, of the river and of the Indigenous people that rely on it.
