How will the Klamath River transform? S14E2

Two people working on research on the river.


The removal of four dams from the Klamath River was a once-in-a-lifetime opportunity to capture the interplay of science, engineering, and culture. Desirée Tullos, professor of water resources engineering at Oregon State University assembled a collaborative team that unites Western science and traditional ecological knowledge of Indigenous people.

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Season 14
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MUSIC: “Shallow Water,” by Yehezkel Raz, licensed through

BARRY MCCOVEY: The effort, the coordination, the collaboration that it took to get to where we're at today with dam removal was monumental. And we're going to use that momentum hopefully to build on that success to move towards a more balanced river ecosystem.

ROBERTSON: That’s Barry McCovey Jr., a Yurok Tribal member and director of the Fisheries Program for the Tribe. The audio clip is from the second episode of “What it Takes to Take Down a Dam” — which I’ll tell you more about later.

This idea of balancing the river that Barry talks about is something that has captured people’s interest. Can it be done? Will the salmon come back? Will the water quality improve? Can the land be restored to native vegetation?

What I’ve learned so far in putting together this podcast season is that there are a ton of passionate people who are doing their best to make that happen.

I’m Rachel Robertson, and in this episode we are continuing the season about the Klamath dam removals: taking a deeper look into the issues on the Klamath, and hearing about a study to track the changes on the river now that the dams are open.

MUSIC: “The Ether Bunny,” by Eyes Closed Audio, licensed under CC by 3.0]

ROBERTSON: From the College of Engineering at Oregon State University, this is Engineering Out Loud.

ROBERTSON: Most people I talk to have heard something about the Klamath dam removals. Many know more than I would expect. Desirée Tullos is perhaps even more interested in what is happening on the Klamath than the average person. She is a professor of water resources engineering here at Oregon State University.

DESIRÉE TULLOS: And I study rivers, essentially the sustainable management of rivers. But the way I think about it is I study river hydraulics and its connection to things that people care about, whether that's infrastructure, or fish, or people. And at the core of my work, it's all about river hydraulics, but hopefully connecting with things that people care about.

ROBERSTON: Desirée also cares about rivers for personal reasons. She is an avid boater, open water swimmer, and general river lover. And she has been working and recreating on the Klamath River for the last 20 years, including research on one of Oregon’s first dam removals at Chiloquin, located in the upper Klamath basin. So, as you might imagine, she was following the proposal to remove dams from Klamath that had been in the works for three decades. For her, it was an opportunity to learn.

TULLOS: There was this gap around science with the Klamath dam removals and we all saw the train starting to leave the station, but nobody was really clear when it was going to happen. And so, there's a bunch of us kind of just sitting around waiting ... things were stalling, there were political changes. And, all of a sudden then it was like, “go, it's going to happen.”

[MUSIC: “On a Wing,” by Podington Bear, licensed through]

ROBERTSON: That moment propelled Desirée into action. She and her collaborator Bryan Tilt, a professor of anthropology, put together a proposal that was funded by Oregon Sea Grant. That laid the groundwork for an even bigger proposal also funded by Oregon Sea Grant with more collaborators, including a partnership with the Yurok Tribe.

The scope of the study is large: How will river health and ecology transform? What cultural changes will happen for people living there? How can different ways of knowing, such as Western science and traditional ecological knowledge of Indigenous people, be united?

To answer these questions, they assembled three research teams: an ecological team to examine water quality changes, a sociocultural team to document the changes witnessed by people who live and work on the river, and a decision-modeling team to bring those two streams of knowledge together, along with what is learned from the Yurok Tribe.

Desirée is heading the ecological team and although she expected that water quality would improve — the speed at which it did was faster than what was expected and the worst of the anticipated water quality impacts never materialized. You might remember from the last episode, Mark Bransom said the sediment would take one to two years to clear out of the river. I did this interview with Desirée in January before the dams had been removed and everyone was still expecting to see some negative impacts.

TULLOS: There'll be the short-term change where the stored sediment, which a lot of it is really fine material, a lot of it is old dead algae. And the negative impact mostly is associated with how it's going to suck dissolved oxygen out of the water. But most of that sediment is going to ... there will be some deposition of long margins ... but most of that's going to end up out of the ocean.

ROBERTSON: That still happened, but it was not as bad as expected. Desirée and her team have hypotheses about why the river cleared earlier than people thought it would, and data collected during drawdown will help flesh out that science. While the US has removed over 2000 dams, very few of them look like the Klamath. As a result, there were not a lot of previous data to create accurate predictions for some aspects of the Klamath dam removals. The winter and spring flows were also less than expected, which means that there was less erosion in the former reservoirs. The good news is that one of the biggest anticipated ecological impacts, a widespread loss of fish due to a lack of oxygen, never happened. There were only two periods when the dissolved oxygen levels dropped low enough to kill fish. While some fish were lost during those periods, the impacted area was much smaller than the engineering models predicted prior to dam removals, and the oxygen returned to non-lethal levels within hours.

This was very different from what she observed after the McKinney wildfire in the summer of 2022. The severe fire, followed by heavy rainfall, caused erosion on the steep hillslopes of the Klamath River tributaries. The debris flow generated a large input of sediment, which sucked oxygen out of the water and killed thousands of fish. One of Desirée’s algae study sites was buried in sediment.

TULLOS: I underestimated how much the sediment was going to impact the algae just from a light perspective. You know, I was thinking about the burial of plants and algae, but just the fact that there's no light in river because it's like chocolate milk. We were out there sampling and it was

[MUSIC: “Back Stairs,” by Podington Bear, licensed through]

four feet of just muck that's sitting on top of these gravel bars. Yeah, it was a very stark contrast in terms of how much that sediment delayed the green up of the algae in the plants.

ROBERTSON: It seemed reasonable to expect the sediment pulse from the McKinney fire would be a preview of what was to come with the dam removals, and her crew will be back out there this year to see if the McKinney fire was in fact a reasonable preview of dam removal impacts. But with the water quality already clearing up and the deposited sediment flushing out, there may not be much impact to see. Instead, they are hoping to catch an early glimpse of some of the benefits of the project. She is looking forward to snorkeling in a river that isn’t carrying the remnants of toxic algal blooms.

TULLOS: The big benefit of these removals ... there's a couple of them. One is that the fish won't be trapped downstream of Iron Gate Dam. And in this hyper infectious zone where there's a lot of fish disease risk, so they'll have more access to spread out, which should help reduce fish disease risk. But also, those reservoirs are these cesspools of toxic algae. And the river, you know, ever since I've been working down there, which is almost 20 years, and I'm sure it's been going on much longer than that, they have contact advisories. The concentrations of toxins is so high, both in the reservoirs and in the river. So, it will get rid of those blooms. Those will be gone. The temperature regime of the river will be more natural. There are these big important benefits from a water quality and fish ecology perspective.

ROBERTSON: While the emphasis in the past has been on the floating algae that produces toxins in reservoirs, aquatic plants and attached algae can also be a nuisance, clogging boat motors and tribal fishing nets. If you have ever swum or paddled in the river that is full green stuff, you know it can also be pretty unpleasant to look at. The question of how dam removals may change plant and algae growth is interesting to scientists and water resource managers, because it is relevant to wildfires and other disturbances that introduce a lot of sediment to a river.

[MUSIC: “Electric Car,” by Podington Bear, licensed through]

To get a baseline assessment of algae and plant growth, Desirée and her team traveled to the Klamath River every two weeks in the summer of 2023 doing field work. They traveled to two downstream locations and made measurements at 20 sites. They identified what kinds of aquatic plants and algae were growing there and under what conditions: light levels, water depth and velocity, and habitat features, such as the type of rocks they were growing on. They will return to those sites every year and take the same measurements. With those data, they’ll be able to test hypotheses about how the infrastructure, river processes, and the ecosystem are connected.

TULLOS: There's an expectation that our restored variability and dynamism is really essential to fish in particular, but other organisms in the river too, and that that's a key part of the pathway to recovery of fish.

It's like we've eliminated so much of that variability that the ecosystem needs. And so, we're watching these experiments unfold and how does the ecosystem rediscover that variability and how long does it take? It's a big natural experiment.

ROBERTSON: So, how do you deal with those unknown factors as an engineer?

TULLOS: That's a really good question. It's something we work a lot on with our undergraduates in the ecological engineering program. I think that's one of the things we really emphasize with them is: Most of the systems that you work on aren't like the kind of calculations we do in class, right? Where you have a single right answer, you put a box around it. Where the reality is most of these systems are really complex. There's a lot of interactions, a lot of which we don't really even understand.

That's certainly the case, especially with water quality. It's environmental chemistry, it's microbiology. I mean, it is engineering, obviously, and infrastructure. And so, we deal with it in a lot of ways we use models we do a lot of environmental sensing, use innovative instruments and sensors to fill in the gaps.

And then what this project is also trying to do is to say, okay, there are things that we can't measure as Western scientists. Either we weren't there or it's a process that we don't understand well enough. And so that's why we're talking to people who are on the river every day.

ROBERTSON: One of the things that people are concerned about with the Klamath is that 90% of juvenile salmon are infected with a deadly pathogen, Ceratanova shasta. It's carried by tiny worms believed to feed on algae. Part of the Sea Grant funding is supporting research by Julie Alexander, assistant professor of microbiology at Oregon State, to study the river conditions that help the worms to thrive and how that changes once the dams are out. I got to meet Julie last summer on the Klamath River (before the dams were open) where she was doing field work.

JULIE ALEXANDER: I’m interested in water quality and algae because these worms are filter feeders and they naturally occur, but between the dams and flow stability and then all the additional nutrient input from various land use practices in the basin, these worms are in the mecca right now. So, dam removal will knock them back substantially just in terms of having more flow variability, but the water quality issue has yet to be addressed. So, this is going to be a really cool opportunity to start looking at those linkages.

ROBERTSON: Julie’s work on the worms will continue and the field crew will return over the next two summers to track changes in plant and algae growth at the two original locations, plus a third farther upstream where they have already begun testing oxygen levels. I asked Desirée why she added the third site to the study and I got more of an answer than I was expecting.

TULLOS: And there's a few reasons for that. One is that it's closer to the dams. So, probably, we expect it to be more impacted by the deposition side of things. And, you know, we wanted to have a gradient of sites and so the first year we really wanted to get our methods dialed down, really had a good baseline set of data but started to realize, I mean, to appreciate how much the tributaries matter in terms of delivering fresh water and clear water and flushing things out. So, it also overlaps with some of the other work that the USGS is doing and Julie Alexander with her fish disease risk. So, it's kind of a hot spot of a lot of science, too. So, there's a lot of reasons to add that site.

ROBERTSON: Desirée went on to explain how adding that site, called Tree of Heaven, also represents the collaborative approach that defines this project.

[MUSIC: “Ringling,” by Podington Bear, licensed through]

TULLOS: And that's a spot that has a lot of meaning for me personally, for a variety of reasons. But one of them is that it was at the Tree of Heaven where I sat down with Laurel and Julie and Liam from the USGS, like around a campfire. And we're all realizing we're doing these things that are related to each other. And the questions ... starting to ask the questions like, how can we build actually something bigger than just what we're all doing individually? And so, you know, co-locating sites is one part of it, but also making adjustments. Like one of the things Julie is interested in related to the disease risk ... fish disease risk ... is carbon. There's these worms, they're filter feeders, they suck everything out of the water. And how does how much carbon is available to them matter in terms of how dense they are, how fecund they are, how many, how much offspring they produce. And so, we now have this more ... a stronger component of carbon in our study than we would have before, because there's a connection there that we ... I didn't initially anticipate, as you know, hydraulic engineer essentially. And so, yeah, it's been this great opportunity to sort of do like campfire science where we all sitting around really wanting to work together and make this sort of bigger than the sum of the parts.

ROBERTSON: I’ll tell you more about the parts of this project next. But first, I wanted to acknowledge that there are a couple people Desirée just mentioned who I haven’t told you about yet. Laurel Genzoli is graduate student at University of Montana who is working with the ecological team on this project. Liam Schenk is a science advisor at the USGS who is also studying the impacts of the Klamath dam removals. It's already getting hard to keep track of everyone, and we are just scratching the surface of the dizzying number of people who are contributing the science of the Klamath River and the dam removals.

And now for the rest of the parts of this project. The team studying the sociocultural impacts is a collaboration between Oregon State and the Yurok Tribe. Bryan Tilt, who I mentioned is co- principal investigator on the project, heads the team that includes Oregon State graduate students. Barry McCovey, who you heard at the beginning of this podcast is also part of that team along with Brook Thompson, a Yurok Tribal member and doctoral student of environmental engineering at UC Santa Cruz. She was in the first episode.

TULLOS: We're doing a bunch of surveys and interviews with people. And the idea is to document their knowledge. And we are thinking about this as like multiple ways of knowing. So, for example, if you're a tribal fisher person or you're a whitewater recreational guide, you're on that river every day in the summer and you see things that we as Western scientists probably aren't seeing and you understand what the impacts of that water quality is on people. So, we're doing a lot of surveys and interviews to essentially try to document their knowledge of what's happening in the river, how it's changed over time and what role water quality is playing in that.

ROBERTSON: In addition to talking to people in Yurok Tribe and whitewater recreation outfitters, they are also talking to people in commercial and charter fishing industries, conservation organizations, and agricultural communities. Everyone is contributing their expertise toward the development of new models of the Klamath system that include ecological and cultural information. The modeling is the next part of the project.

TULLOS: Then there's a decision modeling piece and that's where we bring those two parts together, that ecology, sort of numerical modeling that we do as Western scientists. And then the multiple ways of knowing, things that we're documenting, for example, from the tribes or from the different — we have five different invested parties, groups of people that we're doing the surveys with. So, bringing those two knowledge systems together and doing some computer simulations with that knowledge. So, kind of like gaming, we're building this online shiny app where people can go in and say, “Well, if you impact nutrients in this way or impact flow in this way, this is what you can expect, for example, with algae or with fish disease risk.”

So, it's trying to bring together a lot of layers of information, some of which comes in the form of stories, some of which are like these scaled questions where you ask people like, “Is this acceptable or not acceptable in terms of like levels of algae?” And we do computer simulations with that and we also push that back out as a product so that people can understand the river better and the water quality of the river better.

ROBERTSON: That decision-making team is headed by Jim Peterson, assistant professor of fish, wildlife, and conservation sciences at Oregon State who is advising a group of students working on that piece. Desirée is also heading the last part of this project which is outreach to the public.

TULLOS: The outreach and engagement part, part of that is associated with the sociocultural piece where we are out, you know, actually trying to document the knowledge of people who have this multi-generational experience with the river. Part of it is our audience is the general public. And so, there's been a ton of media, people coming, sort of helicoptering in, telling this one specific story in particular, for example, about the role of the tribes and how important that's been in terms of pushing dam removal forward. But there's a lot of other experiences and stories about what's happening on the river right now that we were trying to document and push that back out to the public.

So, part of that that process has been the podcast. We're doing a lot of different like science pubs and seminars and presentations in the basin. So, obviously other scientists are part of our audience too. But when I think about the outreach and engagement part I think, telling the more complete story of what's happening with the dam removal and the context in which those things are occurring has been important and kind of missing from the mainstream media at least the way they're telling what's happening, what's going on down there.

ROBERTSON: The podcast she mentioned is called, “What it Takes to Take Down a Dam,” which I borrowed a clip from at the beginning of this podcast. It’s a comprehensive look at the different perspectives that people have about the dam removals including landowners who have concerns about how the removals will impact their homes and properties, and river guides whose livelihood is threatened. If you are interested in that deeper dive, you can search for "What it Takes to Take Down a Dam,” on any podcast app.

Desirée also wants to reach a younger audience. She will be working with Oregon State Extension to develop materials for K-12 students.

TULLOS: It's developing these online educational tools that are associated with like how the river works and what role water quality plays. And a big part of that too, is documenting some of the things that we've learned ... that we're learning from the Tribe. And the tribal interviews include the elders, but also fisher people, and people who have spent a lot of time in the landscape, but also have experienced it in different ways. And so, a big part of it is documenting the tribal knowledge about the system, but also from a Western science perspective and putting that into a format online where kids K through 12 can access it and utilize it in their classes.

ROBERTSON: Her team has also developed an internship opportunity so tribal youth can participate in the science. Oregon State University undergraduate and graduate students are also part of the research. You’ll hear from more of them in the next episode. Desirée also took undergraduate and graduate students in her river engineering class on a rafting trip down the Klamath before the dams came out. There is a film about trip that you can find in the bonus content for this episode.

To close this episode out, I asked Desirée if she felt that the dam removals are moving towards rebalancing the river and if so, what role engineers have played in that.

[MUSIC: “Detroit” by Podington Bear, licensed through]

TULLOS: I do think there is more sort of a balancing of ecological values of the variability and the dynamism of the river — recognizing that those dams created pretty significant negative impacts that can't be mitigated. There's not any way to get fish passage around those three dams effectively, you know, in a cost-effective way that actually protects the fish. There's not really a good way to get rid of those harmful algal blooms. So, there was a sort of reckoning or rebalancing of priorities. And you know, prioritizing tribal interests.

And then the role that the engineers have played I think is pretty profound in terms of the whole dam removal process. Which, you know, you look at the construction of dams over 100 to 200 hundred years ago, some of that's pretty impressive, right?

Like what we went through as engineers to figure out how to design these dams. But there's also been a lot of innovation around how to remove dams, how to remove that infrastructure, because you don't just take it out the same way you put it in. Now you've got decades worth of sediment, you've got it full of water, you've got parts of the infrastructure that are no longer functional.

So, I think that there's a really innovative part in terms of the engineering of removing large infrastructure that translates not just to removal but to other large infrastructure. And then, also, a huge role that engineers are playing in terms of restoring the site afterwards. One contractor in particular that's responsible for that has a team of both engineers and ecologists working together to figure out how to stabilize sediment, how to restore vegetation, how to create a post dam removal condition, that people do go look at and get inspired by rather than some ... the perception of this big stinking mud flat that, you know, is going to be full of invasive plants.

And then there's also the monitoring. I mean, there's so much work that the USGS is doing as a group of geologists, geomorphologist and engineers as well as other researchers that are working in the basin to, like, monitor what's happening. To create the sensors, to put the sensors in, like lasers that they're using to monitor the river changes, like the shape of the channel, and how it looks or, yeah, the instruments we are using to monitor water quality. So, there's environmental sensing aspect to it too that engineers play a big role in.

ROBERTSON: And a final word here from Barry McCovey Jr.

MCCOVEY: We believe as the river starts to heal itself, the people will also start to heal. And that’s something we are really looking forward to.

ROBERTSON: Thanks for listening. This is a really amazing project that I have loved learning about and I appreciate Desirée for taking the time to explain it to me. I’m also very grateful to the Spring Creek Project which enabled work on this podcast by awarding me a week-long residency at Shotpouch Creek cabin where I interviewed Desirée and spent a lot of time trying to wrap my head around this very complex project. Thanks to my coworkers: Steve Frandzel, Chris Palmer and Owen Perry for reviewing my script. You can find bonus content and the full transcript at

ROBERTSON: So, is there a role for a healthy river ... are you getting cold now?

TULLOS: No, I’m excited!

ROBERTSON: OK, that’s good! [laughter] So, is there a role of sediment in a ...