Predicting river temperatures

Fishing for salmon along the Klickitat River is in Ira Lee Yallup’s DNA.

An enrolled member of the Confederated Tribes and Bands of the Yakama Nation, Yallup catches salmon with dip nets, a method his family and ancestors have been using for generations.

He stands on a hand-built wooden platform about 40 feet above Lyle Falls. Then he maneuvers a 30-foot pole with a large hoop and net at one end — imagine a butterfly catcher on steroids.

With skill and precision, Yallup swoops the net through the rushing river before he sweeps it up, and with a little luck, harvests a Chinook or Coho salmon, sometimes weighing up to 40 pounds.

“Fish is a livelihood. Fish is our food. It’s in our ceremonies,” Yallup said. “It’s very important in our culture, our tradition, way of life, food, you name it. You know, it’s valuable, very valuable.”

The salmon runs — a natural resource critical to communities, the ecosystem and businesses throughout the state of Washington — are under threat. Development has devastated salmon stocks in rivers throughout the Pacific Northwest. Dams, agriculture, industry and now global warming make it harder, sometimes impossible for salmon to return to their spawning grounds.

Southern Resident orcas, who exclusively eat salmon, feel the impact of these endangered runs. The region’s Native American and First Nation tribes, including the Yakama Nation, feel it too. Salmon is central to their way of life.

Recent efforts to restore salmon runs include dam removal, agricultural regulations and active river management. To better understand the plight of the rivers, scientists collect troves of data to manage the fishery.

The Columbia River Inter-Tribal Fish Commission, or CRITFC, is the fisheries coordination organization for the Yakama Nation, the Confederated Tribes of the Umatilla Indian Reservation, the Confederated Tribes of the Warm Springs Reservation of Oregon and the Nez Perce Tribe. CRITFC is helping to manage the fishery in the Columbia River, the largest watershed in the Pacific Northwest.

Now these fishery managers have a new tool. A team from the University of Washington Department of Civil & Environmental Engineering has devised a way to extract river temperatures from NASA satellite images. Using advanced computing and machine learning, the UW created a website that charts precise temperature for remote river locations across Washington. Notably, the data isn’t just current observations, but historic readings that allow scientists and resource managers to look at river temperatures going back more than four decades.

“Water temperature is one of the key attributes, environmental attributes, that determine if a fish is going to survive in the Columbia River,” said Elaine Harvey, CRITFC’s watershed department manager. “This tool is directly related to water temperature, and we can utilize it for management of salmon.”

THORR: Wielding a mighty hammer to sift through data

In the early 1970s, NASA launched a satellite — called Landsat — to create a long-term record of Earth. While NASA has sent newer, more advanced Landsat satellites since then, the overall mission remains the same: Use imaging technology to produce a continuous and consistent archive of the planet and track the impacts of human development.
The NASA archive of downloaded data from these satellites is publicly available and researchers around the world have tapped it. Having access to historical data going back decades enables scientists to identify trends.

Extracting useful and practical information from the satellite downloads, however, can present challenges for everyday users.

Enter the UW. George Darkwah, a civil and environmental engineering doctoral student, came to the UW to combine his interests in hydrology and big data. He and a UW team, working with Faisal Hossain, a professor of civil and environmental engineering, started to brainstorm possibilities.

At the UW, Darkwah, who is from Ghana, learned of the importance of salmon to local Native American cultures, the Pacific Northwest and the regional economy. Darkwah realized he could use his skills to build a tool to help support a healthy ecosystem for salmon and the people whose lives depend on healthy fish runs. As part of his doctoral work, Darkwah dreamed that he could help make an impact.

Hossain pointed Darkwah toward using NASA satellite images to tell a story about river temperatures. Darkwah started combing through the data that was available — NASA images on heat signatures and regional topographical maps, historic weather reports, existing river gauges and in-river temperature indicators, among other sources.

To make sense of all this and to convert NASA images to corresponding river temperatures, Darkwah used advanced machine learning, essentially artificial intelligence, to sort through all the data and forge it into useful information.

He created an open-source tool with a website, Thermal History of Regulated Rivers, THORR, named after Thor, the mythical Nordic god and Marvel character who wields a mighty hammer.

“You’ll be able to enhance the tool progressively, develop it and then you can be a superhero in this area that we are studying,” Darkwah said.

The website allows any computer user to access water temperature and other critical information along even the most remote river locations of the Columbia River basin. And the beauty of the site is that someone using a laptop can add new data sources and update the training data or algorithms.

“The possibilities are boundless and endless,” Darkwah said.

There are existing temperature gauges in the rivers, but they’re limited by access. THORR eliminates access obstacles. On cloudy days, THORR can still provide temperature readings by modeling historical weather and geographic data and conditions. That’s where the machine learning algorithms come in and crunch the numbers to spit out a reading in even the most remote streams and rivers.

Bridging technology with the people who fish the Columbia

Darkwah and Hossain knew they wanted to create a tool that would benefit the people who fish on the Columbia River and its tributaries.

In April 2023, they reached out to CRITFC to share an early version of THORR.

Harvey, who also is a member of the Yakama Nation, was eager to learn more about the ability to access river temperature data in remote locations, and review how temperatures have changed over time. Fluctuations in temperature can threaten salmon, and if the river gets too hot, the fish can die.

“It’s imperative that we understand what’s happening in the Columbia River, the water temperature, because the fish have lethal limits,” Harvey said.

Having a sophisticated tool like THORR was “a blessing, because the salmon are so important to us,” she said.

“The salmon are part of our life. It’s part of our daily diet, what we eat at home,” Harvey continued. “And every year it’s a deep concern, a great concern for the tribes — when the water temperatures are excessively high — because we don’t want salmon kills.”

Now, CRITFC is working with the UW to determine how best to support THORR on a longer-term basis.

Using the data from THORR, CRITFC can make policy recommendations to the Bonneville Power Administration and the Army Corps of Engineers, the two organizations that manage dams along the Columbia River. Releasing colder water from dams upstream is one strategy that could lower temperatures for salmon survival.

“It was a really good collaboration between the tribes and the University of Washington to work together,” Harvey said.

‘We want to heal you’

“When we collaborate, we create,” said Davis “Yellowash” Washines, a Yakama Nation tribal elder who advises CRITFC.

By working with the UW, with CRITFC and with other tribes, he said, he is helping to preserve the right to fish, to use the land, to uphold his traditions for the next generation — to honor his caretaker role.

“We have a responsibility to our mother, to this ground, to water, to our way of life,” Washines said.

Just like when a physician takes a person’s temperature, so too does the water temperature tell a story about the health of the river. And just like a doctor who dispenses medicines to bring down a fever, understanding river temperature fluctuations allows natural resource managers to prescribe solutions.

“We want to get you well. We want to heal you,” said Washines, who also is vice chair of the Native American Advisory Board at the Burke Museum. “We need to get that temperature down to heal you.”

Virgil Lewis, Sr., another Yakama tribal elder and a CRITFC commissioner, remembers climbing to a hill perched above the Klickitat River as a little boy.

From that vantage, he could look at the river and see it flush with salmon, more than he could count. Today, from the same spot, Lewis said there may be one, sometimes two fish.

While change — removing dams, dredging silt, restoring fish runs — may take decades, the work must happen, Lewis said.

“We have generations that are coming up. I have grandchildren, great grandchildren, that someday will be taking my place fishing,” he said.

Darkwah, the UW grad student who built THORR, also has a vision of returning home to Ghana to use technology like THORR to help support communities there. In the meantime, he said, connecting with elders including Washines and Lewis adds a dimension to his doctoral research and teaching.

“Knowing that my work has an impact out there, it makes me feel more satisfied within,” Darkwah said. “I know that whatever I’m doing is for humanity.”

Northwest Public Broadcasting and Public News Service published related stories.