Water managers releasing cold water from Lake Powell to fight invasive fish
Jul 19, 2024, 1:00 PM | Updated: 1:30 pm
The Glen Canyon Dam holds back the waters of Lake Powell in Page, Arizona, on July 18, 2022. (Spenser Heaps/Deseret News)
(Spenser Heaps/Deseret News)
LAKE POWELL, Ariz. — Water managers with the Bureau of Reclamation have begun conducting strategic cold water releases from Lake Powell to fight invasive fish further down the Colorado River.
The agency is working to combat the reproduction of invasive smallmouth bass in the Lower Colorado River Basin. The bass live in the Upper Colorado River Basin, including Lake Powell, but, for years, they never got through the Glen Canyon Dam.
Related: Bear Lake Watch working to control invasive species in the lake
Wayne Pullan, regional director of the Upper Colorado Basin Region for the Bureau of Reclamation told KSL NewsRadio the bass stick to the upper, warmer levels of Lake Powell.
But, after Lake Powell hit a new record low in 2022, smallmouth bass were able to tolerate the water temperatures near the dam’s penstocks and got through. They were later discovered reproducing in the Colorado River below the dam.
Lake Powell ended up hitting another new record low in early 2023.
The problem: the bass moved into humpback chub habitat, and are now able to prey on them.
Pullan said they have worked to protect that species for years, and got it reclassified from ‘endangered’ to ‘threatened’ in 2021.
“Now all of that progress is potentially at risk,” Pullan told KSL NewsRadio.
Cold water releases
Lake Powell’s capacity has nearly doubled since hitting a record low of about 22% capacity in early 2023.
According to the Utah Division of Water Resources, at the time of publication, Lake Powell was 42% full, its highest level since 2020.
With all the new cold water, officials have begun sending water through the dam’s river outlet works, or bypass tubes, to cool the Lower Colorado River.
The hope is it will make it harder for the bass to reproduce and thrive in the humpback chub habitat.
Pullan clarified that these releases would not have an impact on Lake Powell’s water levels, or how much the water they normally release to the Lower Basin each year.
“We’re not releasing any more water…we’re just releasing it through different means,” Pullan said.
However, since the cold water releases are not going through the dam’s penstocks, Pullan said it would affect how much hydroelectricity the dam can produce.
He said they are working with the Western Area Power Administration so they can limit the impact on hydropower.
According to the Bureau, Glen Canyon Dam produces roughly 5 billion kilowatt-hours of hydroelectric power a year. That power serves people in Utah, Wyoming, Colorado, New Mexico, Arizona, Nevada and Nebraska.
Pullan said the releases will continue possibly through September. But, he said they will likely have to do something to combat the invasive fish for, “a fairly long time.”
“If we have the resources to be able to protect [endangered species], we certainly should,” Pullan said.
Adam Small is a reporter for KSL NewsRadio. He primarily reports on the Great Salt Lake and Natural Resources. Follow him on Facebook and X.
