River Rebalance

Desiree Tullos at the Klamath Dam

Desiree Tullos at the Klamath Dam

River Rebalance

Researchers examine historic dam removals on the Klamath River

On Jan. 11, Iron Gate Dam was blasted open, marking the first step in removing three reservoirs from the Klamath River. It was a moment that many wondered if they would ever witness. What seemed like an impossible mission was achieved through 30 years of collaboration between tribal members, scientists, engineers, and staff from government agencies and conservation groups.

The biggest dam removal in the U.S. is more than a monumental engineering project. The hope is that it will restore some balance to a damaged ecological system.

When the dams were constructed in the early 1900s, it was a great achievement of engineering. Built for hydroelectric power, the dams produced cheap, clean electricity that became the foundation for growth and commercial prosperity in the area.

But there was a cost, especially for the tribal communities who depend on the river for food and their way of life.

The Cost of the dams

“The Klamath used to produce the third-largest salmon runs on the West Coast. Now, salmon are at only 8% of their historic population,” said Desirée Tullos, professor of water resources engineering at Oregon State University.

Over the past century, the health of the river has declined. And today, the impacts of dams are better recognized and understood.

New regulations require compliance with the Clean Water Act and the Endangered Species Act. PacifiCorp, owner of the Klamath dams, decided it would make better business sense to take the dams out than to pay for expensive upgrades that might not even work.

Map of the Klamath Rover dams, including the four to be removed, along the border of Oregon and California

Map of the Klamath Rover dams, including the four to be removed, along the border of Oregon and California

the Project

A total of four dams are part of the dam-removal project. The smallest dam, Copco 2, was the first to go, in June 2023. Iron Gate and the other two dams, Copco 1 and J.C. Boyle, will be demolished this summer. Two dams in the upper basin of the Klamath River will remain to support irrigation.

Opening the Iron Gate Dam was a symbolic moment, a key first step in unblocking the river to fish passage and resetting ecological processes on a large scale. The land exposed by the draining of the reservoirs sets the stage for the last step of the project — restoring natural ecology by planting and reseeding with native plants.

For researchers, the project is a critical learning platform for future dam removals and for the operation and maintenance of current dams. It also allows them to gain a deeper understanding of how rivers respond to events like wildfires. Tullos saw it as a once-in-a-lifetime opportunity to capture the interplay of science, engineering, and culture. She is the principal investigator for a study funded by Oregon Sea Grant to investigate the impacts of the dam removals.

Copco 1, one of four dams on the Klamath targeted for removal, is slated to be demolished this summer.

Transforming Ecology

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?

The nature of the project required researchers from diverse areas of study, as well as collaborations with the Yurok Tribe, whitewater recreation outfitters, 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.

Three research teams are part of the project: an ecological team examining water quality changes, a sociocultural team documenting the changes witnessed by people who live and work on the river, and a decision-modeling team bringing those two streams of knowledge together. Tullos heads the ecology team looking at the water quality of the Klamath River. Specifically, her research focuses on how oxygen in the river changes with the dam removal, and what factors underpin algae and aquatic plant growth and fish health.

“We have some interesting ideas around what’s going to happen after the dam removals, and it’s all related to how the infrastructure, river processes, and the ecosystem are connected,” Tullos said.

Heading up the ecology team on the dam removal project, Tullos collects sediment samples from the Klamath River in spring 2023.

Heading up the ecology team on the dam removal project, Tullos collects plant and algae samples from the Klamath River in spring 2023.

Ecosystem & Water Quality

The water quality of the Klamath River has been suffering for decades from stagnation in the reservoirs. Toxic cyanobacteria have risen to levels unsafe for humans. Algae deplete oxygen levels and change the acidity. These conditions, and the increased water temperature caused by the dams, all stress the fish.

Additionally, up to 90% of juvenile salmon are infected with a deadly pathogen, Ceratanova shasta, carried by tiny worms believed to feed on algae. Part of the grant is supporting research by Julie Alexander, associate professor of microbiology, to study the river conditions that help the worms to thrive and how that changes once the dams are out.

“There are big benefits of the dam removals for water quality and fish ecology. The fish won’t be trapped But it will take a while to get there. As the reservoirs were drained, millions of cubic yards of sediment and old, dead algae that has been trapped behind the dams were released into the river.

“It looks like chocolate milk. The river is thick with sediment,” Tullos said. It could take one to two years before the excess sediment clears. Suspended sediment blocks light needed by aquatic plants and algae and decreases dissolved oxygen. Tullos expects that, initially, a lot of the plants and algae in the river will die off.

Tracking Biomass Over Time

To get a baseline assessment of algae and plant growth, Tullos and her team spent the summer of 2023 collecting biomass and sediment samples and making hydraulic measurements every two weeks at 20 sites based at two downstream locations. They identified what kinds of 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. “The Klamath River is like a garden that has a ton of plants growing in it,” Tullos said.

“It’s unique in that regard because it’s so productive. But that can be a problem when that growth clogs fishing nets and boat motors, and it can deplete the oxygen in the water when the plants decompose.”

The ecology team 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. In January, the team began testing the river to understand what is driving the varying dissolved oxygen levels as the dams are removed.

“Our hypothesis is that the plants and algae are influenced strongly by the velocity of the river that they’re growing in, and also by how much light is available to them,” Tullos said. “Maybe nutrients matter less at times in the Klamath because it’s nutrient rich, but that’s something we’re trying to disentangle. There are a lot of connections that aren’t really well understood.”

Ecological engineering student Whitney Packard checks out particle samples collected from the river. Every sample is labeled by location and taken back to the lab where she runs tests to find out how much biomass is present.

Student Field Work

Students on the ecology team are literally immersed in field work, donning wetsuits and snorkel gear to collect samples and take measurements. They also learn to process samples in the lab and manage data.

“It’s really amazing to have even a small part in something so big,” said Whitney Packard, an undergraduate student studying ecological engineering. “And conversing and learning from the tribal members who are involved in this process is extremely valuable.”

“It’s really amazing to have even a small part in something so big, and conversing and learning from the tribal members who are involved in this process is extremely valuable.”

The team studying the sociocultural impacts involves collaboration between Oregon State and the Yurok Tribe. Bryan Tilt, professor of anthropology, heads the team that includes Oregon State graduate students Barry McCovey, director of the Yurok Tribal Fisheries Program, and Brook Thompson, a Yurok Tribe member and doctoral student of environmental engineering at UC Santa Cruz.

“If you’re a tribal fisher or 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 the impacts of water quality on people,” Tullos said. “So, we’re doing a lot of surveys and interviews to document their knowledge.”

Building a Simulation Model

Jim Peterson, assistant professor of fish, wildlife, and conservation sciences, is advising students focused on building a simulation model to bring the different types of data together. The final product will be an online app that will help people better understand the interplay of different drivers and impacts of river health.

“Our vision is that people could use the app to better understand what would happen when you make changes to nutrients or flow, for example,” Tullos said.

Desiree Tullos

Desiree Tullos


For the outreach component of the project, Tullos is working with Guillermo Giannico at Oregon State Extension. For K-12 education, they are developing online tools that describe how the river works and the role of water quality, including both Western science and Indigenous knowledge. There is also a tribal youth internship program for students to be more directly involved with the research, including fieldwork.

Tullos has given several science talks and media interviews to inform the general public about the complexity of the dam removals. She also produced the podcast, “What it Takes to Take Down a Dam,” in which she interviewed several individuals who are involved with the dam removals or will be impacted by changes to the river. She talked to a diverse group of people including whitewater outfitters, landowners, the Yurok Tribe, government and nonprofit organizations, and conservation groups.

Perspective Shift

The perspective and influence of engineering on the Klamath River has come full circle, from building the dams to tearing them down.

“Engineers came in with a good intention of electrifying a rural area. And now they are part of the removal of the infrastructure when it was realized that it’s outdated and has outlasted its purpose,” Tullos said. “As engineers, we think of ourselves as problem-solvers, and it’s often a push toward more technology, but there’s also a push toward naturalization. And engineers can and should play a role in that.”

Listen to the College of Engineering podcast, “Engineering Out Loud,” to learn more about Tullos’ work.

Story by

Rachel Robertson

May 8, 2024

Photos by

David Baker, Sean Nealon, and Shane Anderson of Swiftwater Films

#CleanWater | #KlamathDam | #BEE | #Biological and Ecological Engineering | #Water Quality

Managing An Historic Dam-Removal Project

Mark Bransom, PhD civil and environmental engineering '97, is CEO of the Klamath River Renewal Corp., a Berkeley, California-based company managing the biggest dam-removal project in U.S. history. In 2020, PacifiCorp transferred ownership of the dams and 8,000 adjoining acres to KRRC to oversee decommissioning of the dams and restoration of the land.

When the work is done, KRRC will transfer the land to the states of Oregon and California. Monitoring the restoration will take several years, so Bransom expects it will be 2030 or 2032 before KRRC’s work is finished. “I consider this the capstone of an amazing career that started at Oregon State University,” Bransom said. “My education positioned me well to do a large variety of things that ultimately led me to this project, and I couldn’t be more thankful to be here.”

Bransom became familiar with the Klamath River area in the 1980s, when he worked in Northern California as a soil scientist in the Six Rivers National Forest. “I came to know and understand the physical river system and the lands, but also, and more importantly, the Indigenous people. I learned about their traditional ways of life and some of the issues that they were facing,” he said. “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 in the Klamath River.”

Before joining KRRC, Bransom worked on water resources and environmental restoration projects for nearly 20 years for CH2M, a global consultancy founded in Corvallis by three College of Engineering alumni and a professor. Bransom became more familiar with the Klamath dams through the company’s support for PacifiCorp’s environmental documentation process, which ultimately led to his position with KRRC.

Excerpts of the podcast series “What it Takes to Take Down a Dam” are reprinted here. To learn more about Mark Bransom and the work of KRRC, watch this video.

Mark Bransom is speaking about the Klamath Dam Removal project as this year’s Dean’s Distinguished Lecture.

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