
Where Beavers Gather
By Kip Carlson
By Sean Nealon
Photos by David Baker
In the summer of 2023, Desirée Tullos and two students from her engineering lab finished an eight-hour day of field work. Midday temperatures approached 100 degrees along the Klamath River in northern California. They returned to the Tree of Heaven campground and walked to the boat ramp to take a swim in the cool, clear river.
A year later, she and her team found themselves once again camping at Tree of Heaven and looking to cool off, but the river had changed. Water the color of chocolate milk lapped against a boat ramp covered with sun-cracked sediment up to a foot thick. And when they stepped into the river, they sank two feet in quick‑sand-like mud strong enough to suck a sandal off a foot.
The Iron Gate Dam before removal.
“The models predicted there’d be a lot of piles of sediment, and it made sense from a physics perspective,” said Tullos, a river engineering professor at Oregon State, sitting at a picnic table next to the boat ramp this June. “But seeing it — somehow it is still a surprise. Somehow, I guess in my mind I thought it was going to flush out into the ocean.”
Surprises are expected when you’re working at this scale. Tullos and her team, alongside other Oregon State researchers, are studying the impacts of the removal of four dams on the Klamath River and the restoration of almost 2,500 acres of land about 15 miles upriver from the campground.
This $500 million project — led by an Oregon State alumnus — is, according to the nonprofit American Rivers, the largest dam removal project in the world.
“The Klamath is just one example of this big broader story of ‘Wow, we’ve got all these big, old dams; what are we doing with them? Are we handing this all off to our kids to figure out, and the grandkids to pay for?’” Tullos said. “I think we don’t pay enough attention to dams as infrastructure and it’s all old, and there’s a reckoning coming.”
Looming over the group’s work, and indeed everything on the Klamath, is the plight of the salmon.
The Klamath runs more than 250 miles along the Oregon-California border, through desert, rainforest and redwoods, to reach the Pacific Ocean. What Tullos and other Oregon State scientists learn here will guide river restoration and dam removal projects to come. But it wasn’t a given that the dam removal and restoration project would happen at all.
The Klamath River runs more than 250 miles along the Oregon-California border, through desert, rainforest and redwoods, to reach the Pacific Ocean. The removal of the four dams (shown here), completed in October, restored almost 400 miles of salmon spawning grounds. As part of the process, water from three reservoirs once used for recreation was drained; the 2,500 acres of formerly submerged lands are the focus of a massive native revegetation project.
Map illustration by Elsa Jenna
It took decades of starts and stops because the people involved — lakefront property owners, whitewater rafters, farmers, Tribes, the utility company that managed the dams, state and federal regulators — often had vested interests in the river that didn’t align.
Once the third-largest salmon producing river in the country, the Klamath’s salmon counts dropped more than 90% over the past century. The dams cut this keystone species off from cool tributaries where the fish used to lay their eggs, creating stagnant zones and allowing fish diseases to thrive. Over the past two years, salmon fishing has been banned in California because of poor river and ocean conditions.
Brook Thompson, a Yurok and Karuk Native American and doctoral student at UC Santa Cruz who is working with Tullos, has had a close-up view of those changes.
“For us, salmon is culture. Salmon is our food source. Salmon is our exercise,” she said, sitting on an island in the river after kayaking with the team. “You just can’t separate our culture from the salmon… without the salmon, we aren’t Yurok. And that’s why it’s everything.”
Thompson is proud of the Tribes’ leadership in the campaign to restore the river. For decades, local Tribes and others found that their interests often clashed with those of people wanting water for farmlands or wetlands.
But calls for the dams’ removal gained urgency after a 2002 decision to limit water released downriver from the Upper Klamath Lake resulted in the death of tens of thousands of Klamath Basin fish, according to the California Department of Fish and Wildlife. It was the largest ever salmon die-off recorded on the West Coast. Thompson witnessed it at 7 years old.
Without the salmon, we aren’t Yurok. And that’s why it’s everything.
“People who were actually organizing protests and rallies and actions and conversations and meetings, they were told initially that [the dam removal] would never happen, and that this was a pipe dream,” she said.
“And yet to see this thing we were told was never going to happen, actually be done, is so inspiring to me when it comes to all these other climate change issues.”
After a night at the Tree of Heaven campground in the summer of 2024, Tullos and the two students set out at 7:30 a.m. and drove a few miles along Highway 96 to a put-in spot. They were making their first kayak trip of the season to scout sites where they can get a better picture of the dam removal’s impact. They were downriver from the 173- foot earthen structure of Iron Gate Dam, the last in the process of being deconstructed. The river runs mostly east-west in this stretch, so the canyon walls were no match for the bright, rising sun.
Tullos and other Oregon State project leaders were about halfway through a three-year project funded by Oregon Sea Grant. It braids Western science with traditional and Indigenous knowledge to clarify how water quality management affects everything from recreation to tribal fishing. The framework they develop will inform future water management decisions.
Desirée Tullos, an Oregon State professor of biological and ecological engineering, and her students are studying how sediment released from the dams’ removal affects the Klamath’s plants and algae. Bottom two images by Sean Nealon
The team inflated their kayaks, loaded them with gear and set off. About 30 minutes later, they spotted a patch of aquatic plants, or macrophytes, and pulled over to take samples. The macrophytes stretched out for about 100 feet, creating a long, string-like layer of green and yellow that swayed in the current.
Tullos walked through sludge-like sediment. Soon she was up to her shoulders in the water, surrounded by macrophytes. “You look like you are taking a swamp bath,” Issi Tang, a master’s student in water resources engineering, said from the shore.
A few minutes later, the team identified a sample location. They pulled out a 1.5-foot square sampling frame made of PVC pipe. The area inside the pipe is the sample zone.
They recorded GPS coordinates. Tullos used a ski pole to measure water depth. Then, with help of printouts of different macrophytes, she identified the type and amount of each in the sample zone. Lily Bell, an undergraduate ecological engineering student, measured water velocity. Tang recorded the numbers on a clipboard. They repeated this process dozens of times.
There’s not much data about what happens to water quality after dams come down. The team’s exacting work aims to remedy that.
“Water quality changes impact aquatic plants and algae, and those are important because they impact things we care about, like fish and fishing,” Tullos said. “There’s a sort of scientific gap around how water quality and these algae and plants are connected. We have this opportunity to learn as the system is undergoing big changes, and that will help us understand these same dynamics in other rivers.”
The importance of water quality is “really underappreciated,” Tullos said. “Part of the reason people ignore it is because it’s really complicated — it’s really complex.”
She and her team were already finding that some of their assumptions were wrong.
This a test bed for how we deal with aging infrastructure in a way that is socially and environmentally responsible.
They understood murky water would impact the growth of aquatic plants, because light can’t penetrate the water deeply. So they were surprised to find plants thriving in dark waters early in the season.
The dam removal demonstrated that another important factor — the elimination of spring floods — may allow aquatic plants to get an earlier start in summer. This is relevant to rivers across the West where flood regulation has resulted in fewer high flow events and aquatic plants appear to be gaining ground.
During much of the 20th century, river engineering meant building dams to generate power, control floods, store water or make passage easier. Dams brought cheap electricity, opened agricultural opportunities and drove regional growth.
The 1935 Beaver yearbook, dedicated to the construction of the Bonneville Dam on the Columbia River, summed up the pride felt then: “No matter what the potentialities of nature, man alone has been able to gain the knowledge necessary to harness the natural power sources of the world and to make possible a new age of industrial development for civilization.”
A River Rediscovered: The dam infrastructure flooded and rerouted the Klamath River for a century. But once the dams were breached, the old river suddenly and dramatically re-emerged. At the former J.C. Boyle Reservoir, the transformation revealed a meandering river valley unlike any other landscape along the Klamath’s winding path from high desert to coastal rainforest, a reminder that the flowing pulse of the river was never truly drowned, just waiting to return.
Today, river engineering focuses on rivers as systems and often involves undoing what was done in an attempt to restore more natural conditions. Building has made way for unbuilding.
The four dams affected by this project were constructed between 1918 and 1962. They electrified the region for the first time and allowed for economic development and growth. Two of the main reasons they were targeted for removal were to improve water quality and establish better fish passage.
But economics are also critical. As with many aging dams, the cost to improve them was no longer justified by the financial return of operating them. In recent years, the dams made up less than 2% of the power generated by PacifiCorp, the utility that operated them.
“This is a test bed for how we deal with aging infrastructure in a way that is socially and environmentally responsible,” Tullos said. “In that way, it is a profound example.”
Mark Bransom, ’91, M.S. ’94, Ph.D. ’97, the CEO of the Klamath River Renewal Corporation, has been working on the Klamath project since 2017. His company is in charge of the demolition of the dams as well as the acres that surround them, which will eventually be transferred to the states of California and Oregon, or another designee, after the restoration is complete.
“I really do consider this the capstone of an amazing career that started at Oregon State,” he said.
Bransom became familiar with the Klamath River area in the 1980s, when he worked in Northern California as a soil scientist.
“I always had a sense that I might make my way back to the Klamath at some point to make a professional contribution to restore balance.”
On Aug. 28, excavators notched a passage through the remains of the Iron Gate Dam, and the Klamath River flowed along its historic path for the first time in 100 years. Chants of “Un-dam the Klamath! Bring the salmon home!” went up as onlookers embraced. The group included Tribal members whose activism resulted in the dams’ removal,as well as Oregon State alumnus Mark Bransom, CEO of the company managing the project (top left, at right).
Standing on a bluff above Iron Gate Dam in the summer of 2023 as workers below prepared for its demolition, Bransom acknowledged the project’s challenges. With so many groups involved, negotiations were sometimes complicated. But tackling this opened the way for positive developments, he said — in particular, restoration efforts that combine traditional ecological knowledge and Western thinking.
Work to remove the dams started in 2023. About a year later, at the end of August, as Tribal partners watched and many embraced, excavators opened a passage through the remains of the Iron Gate Dam, and the river flowed freely along its historic path for the first time in a hundred years.
In all, the project involved moving about 1.3 million cubic yards of material. But it also includes a restoration effort focused primarily on the land once covered by reservoirs.
Crews collected three million native seeds from the project area starting in 2019, according to Dave Meurer, director of community affairs for RES, which is overseeing the effort in partnership with the Yurok Tribe.
Nurseries propagated the seeds until they numbered 20 billion. Mixtures of these were scattered by helicopter and hand to renew the uncovered lands. Yurok revegetation crews sowed more than 27,000 acorns; more than 72,000 live plants were planted. Soon, cracked sediment along the Klamath’s banks began to blush green. The work will continue for several years.
“While it is the largest dam removal and environmental salmon restoration project in the world, I tend to think of it as a resiliency project,” Bransom said. “And a resiliency project not only for these amazing fish, but also for communities who rely on a balanced and healthy Klamath River.
That idea of resiliency resonates with Jerri Bartholomew, a retired Oregon State microbiologist. She and her research team worked for more than 20 years to unravel how a single parasite became responsible for devastating losses of salmon on the Klamath River, as well as how the dams contributed to that.
Bartholomew is also an artist, and her time spent on the Klamath led her to combine science and art in a project called “And the Dams Come Down.” It will be displayed starting this January at the Patricia Reser Center for the Arts in Beaverton.
The 6-foot-by-8-foot piece features an outline of the Klamath River in the background, lines marking the locations of the former dams, and 35 glass salmon — coho and Chinook — that she cast individually.
It’s a dynamic piece created to change as the river changes.
Now that the dams are gone, she has switched their color in the piece from black to white, to symbolize ghost dams.
A similar change will happen to the glass salmon. As time passes and salmon return to points upriver from where the dams once stood, Bartholomew will swap out the white ghost salmon and replace them with naturally colored ones.
“The salmon are extremely resilient,” she said. “If they find that there’s a way to move further upriver now that it’s unblocked, they will do it.”
Back on the river, Tullos and her students navigated sections of Class 2 rapids in their kayaks. They spotted a deer drinking from shore, a turtle sunning itself on a rock and a pelican flying overhead.
Vegetation on the canyon walls was already dry, and fire scars lined the walls just downriver. Every few minutes, the quiet was punctuated by a car passing on the highway.
Though the water was thick and turbid, Tullos saw signs of change. She didn’t anticipate finding aquatic plants, but they persevered, forming large carpets in spots. Diving into the water, she found mussels scattered across the river bottom.
As for the salmon, she doesn’t expect them to recover right away. The fish face too many obstacles, particularly around water quality and water management. These, Tullos said, require a “slow grind” — time — to work out. Still, she is hopeful.
“To me, the source of hope is the strong sense of community and care for the river that exists in the Klamath basin,” she said. “I think there is something unique that is happening here.”
Chinook salmon navigating the waters of the Klamath. (Photo by David Herasimtschuk/Freshwaters Illustrated.)
As it turned out, the Klamath’s salmon were all too eager to play their part in the newest chapter of their story. Just weeks after the removal project was deemed officially complete, salmon were spotted in waters upriver from the former dams — swimming free toward habitat that has been inaccessible for more than a century.
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