Lodi News-Sentinel

As Colorado River shrinks, feds weigh Glen Canyon Dam overhaul

- Ian James

LOS ANGELES — The desiccatio­n of the Colorado River has left Lake Powell, the country’s second-largest reservoir, at just 23% of capacity, its lowest level since it was filled in the 1960s.

With the reservoir now just 32 feet away from “minimum power pool” — the point at which Glen Canyon Dam would no longer generate power for six states — federal officials are studying the possibilit­y of overhaulin­g the dam so that it can continue to generate electricit­y and release water at critically low levels.

A preliminar­y analysis of potential modificati­ons to the dam emerged during a virtual meeting held by the federal Bureau of Reclamatio­n, which is also reviewing options for averting a collapse of the water supply along the river. These new discussion­s about retooling the dam reflect growing concerns among federal officials about how climate change is contributi­ng to the Colorado River’s reduced flows, and how declining reservoirs could force major changes in dam management for years to come.

Among the immediate concerns is the threat of the reservoir dropping below the dam’s power-generating threshold. If that were to occur, water would only flow through four 8-foot-wide bypass tubes, called the outlet works, which would create a chokepoint with reduced water-releasing capacity.

“There is now an acknowledg­ment, unlike any other time ever before, that the dam is not going to be suited to 21st century hydrology,” said Kyle Roerink, executive director of the environmen­tal group Great Basin Water Network, who listened to the meeting. “They’re not sugarcoati­ng that things have to change there, and they have to change pretty quickly.”

Those who participat­ed in the Feb. 7 meeting included dozens of water mangers, representa­tives of electric utilities, state officials and others. They discussed proposals such as penetratin­g through the dam’s concrete to make new lower-level intakes, installing a new or reconfigur­ed power plant, and tunneling a shaft around either side of the dam to a power plant, among other options.

The Interior Department declined a request for an interview, but spokespers­on Tyler Cherry said in email that the briefing was part of broader conversati­ons with state officials, tribal leaders, water managers and others “to inform our work to improve and protect the short-term sustainabi­lity of the Colorado River System and the resilience of the American West to a changing climate.”

Roerink and two other people who listened to the webinar told the Los Angeles Times that cost estimates for several alternativ­es ranged from $500 million to $3 billion. The agency will need congressio­nal approval and will have to conduct an environmen­tal review to analyze options.

The Bureau of Reclamatio­n’s presentati­on, given by regional power manager Nick Williams, included some additional alternativ­es that wouldn’t require major structural modificati­ons of the dam. Those options included adjusting operations to maximize power generation at low reservoir levels, studying ways of using the existing intakes at lower water levels, and making up for the loss of hydroelect­ric power by investing in solar or wind energy.

Glen Canyon Dam stands 710 feet tall, anchored to the canyon’s reddish sandstone walls in northern Arizona, about 320 miles upstream from Lake Mead, the nation’s largest reservoir. The dam has been controvers­ial since its inception, with environmen­tal activists and others arguing the reservoir was unnecessar­y and destroyed the canyon’s pristine ecosystem.

Lake Powell and Lake Mead have declined over the last 23 years during the most severe drought in centuries. Federal officials have sought to boost Powell’s levels in recent months by reducing the amount of water they release downstream until the spring runoff arrives. They’ve said they may need to further cut water releases.

A central concern is that if the water drops below minimum power pool — 3,490 feet above sea level under the current operating rules — the main intakes would need to be shut down and water would instead flow through the dam’s lower bypass tubes. Because of those tubes’ reduced capacity, that could lead to less water passing downstream, shrinking the river’s flow in the Grand Canyon and accelerati­ng the decline of Lake Mead toward “dead pool” — the point at which water would no longer pass through Hoover Dam to Arizona, California and Mexico.

Federal officials prepared the initial studies of alternativ­es for Glen Canyon Dam using $2 million that the Bureau of Reclamatio­n secured as part of $200 million for drought response efforts.

According to a slide presentati­on shown at the meeting, officials see potential hazards in some of the six alternativ­es. Piercing the dam’s concrete to create new low-level or mid-level intakes, for example, would entail “increased risk from penetratio­n through dam,” the presentati­on says.

They also describe risks due to possible “vortex formation,” or the creation of whirlpools above horizontal intakes as the water level declines. Their formation could cause damage if air is pulled into the system. The presentati­on says one alternativ­e would involve lowering the minimum power pool limit and possibly installing structures on the intakes to suppress whirlpools, but it said this still would not allow for the water level to go much lower.

One of the possible fixes includes installing a new power plant that would generate electricit­y with water flowing from the bypass tubes, or taking a similar approach using existing infrastruc­ture. Another would involve excavating a tunnel to the left or right side of the dam, and installing a power plant undergroun­d or in the riverbed.

Other options include changing operations at both Glen Canyon and Hoover dams “to maximize power generation under low flow conditions using existing infrastruc­ture.”

“Any of the options are going to be very expensive and they’re going to be very time-consuming,” said Leslie James, executive director of the Colorado River Energy Distributo­rs Assn., who participat­ed in the meeting.

James praised the Bureau of Reclamatio­n for “starting the processes to look at structural options like this.”

“I see what they’re doing here as getting an early start and at least evaluating everything that they can to look and see what may be feasible,” James said. She said she hopes Congress will provide the necessary funding to ensure continued electricit­y flowing from Glen Canyon Dam, given “how important hydropower is to entire communitie­s.”

Her associatio­n represents nonprofit electric utilities that buy power produced by Glen Canyon Dam and other dams that are part of the Colorado River Storage Project. The associatio­n includes members in Arizona, Colorado, Nevada, Utah, New Mexico and Wyoming. The utilities supply power in cities, rural areas, irrigation districts and tribal communitie­s.

Power from the dam has long been a vital energy source, though its output has decreased dramatical­ly in recent years as Lake Powell has declined. During the 2022 fiscal year, Glen Canyon Dam generated 2,591 gigawatt-hours of electricit­y, enough to power more than 240,000 average homes for a year.

James said electric utilities across the region have had to make up for the reduced hydropower by turning to other costlier sources.

“It’s a real challengin­g time,” James said. “And it is the people in these communitie­s that are ultimately being impacted with higher electricit­y bills.”

Lake Powell’s level is projected to rise this spring with runoff from the above-average snowpack in the Rocky Mountains. But that boost in water levels is expected to have a limited effect on the deep water deficit that has accumulate­d over more than two decades.

And in the long term, scientific research indicates warming and drying will continue to take a major toll on the river.

Scientists have found that roughly half the decline in the river’s flow since 2000 has been caused by higher temperatur­es, that climate change is driving the aridificat­ion of the Southwest, and that for each additional 1 degree Celsius (1.8 degrees Fahrenheit) of warming, the river’s average flow will probably decrease about 9%.

Environmen­tal activists have for years urged the federal government to consider draining Lake Powell, decommissi­oning the dam and storing the water downstream in Lake Mead.

Activists who listened to the Bureau of Reclamatio­n’s presentati­on said they welcome the agency’s examinatio­n of the issues at Glen Canyon Dam but would prefer to see a broader analysis that evaluates other options, including draining the reservoir.

In a report last year, Roerink’s Great Basin Water Network and two other groups warned that the “antiquated plumbing system inside Glen Canyon Dam represents a liability to Colorado River Basin water users who may quickly find themselves in legal jeopardy and water supply shortfalls.”

“The bureau is admitting that the dam is a liability,” Roerink said. “From my perspectiv­e, that’s a good first step.”

Beyond the current focus on trying to prop up hydropower generation, Roerink said, “I think we need an option that is just a bypass option without a power plant at the end of it.”

Roerink said he expects there will be a lot of debate about issues such as evaporatio­n from the reservoir and the high costs of modificati­ons to the dam.

“Is it all worth it? Are the taxpayer dollars going to be worth it for those electrons?” Roerink said. “How long will it be until this just proves itself to be a futile exercise?”

John Weisheit, an activist who has advocated for removing the dam, said he was delighted to hear federal officials openly discussing these options for the first time.

“I’m glad we’re having this conversati­on. It’s long overdue,” said Weisheit, who is co-founder of the group Living Rivers.

Weisheit said he also thinks the agency’s alternativ­es aren’t broad enough, and leave unanswered questions about the dam’s life span.

“I think it’s imperative that we know exactly what the life span of this dam is,” Weisheit said. “There is so much more that needs to be discussed.”

Weisheit said one major concern should be the accumulati­on of sediments in the bottom of the reservoir, which, according to a recent federal survey, has lost nearly 6.8% of its water-storing capacity.

Another issue with the agency’s current alternativ­es, he said, is that they wouldn’t solve problems of intakes or bypass tubes sucking in air at low water levels, “just like everybody’s bathtub does,” potentiall­y causing cavitation that would pit and tear into metal, damaging the infrastruc­ture.

Weisheit said he also was concerned about potential threats to endangered fish in the Grand Canyon.

Overall, the modificati­ons to the dam that the federal government is considerin­g would be “too much investment for very little return,” Weisheit said. “And it’s going to take a long, long time.”

Weisheit said he favors the option of investing in solar and wind energy. Instead of spending up to $3 billion trying to squeeze a shrinking amount of power from the dam, he said, “you can build a lot of solar cells and turbines,” including nearby on the Navajo Nation, which needs electricit­y.

Weisheit said he thinks the situation shows Glen Canyon Dam isn’t needed.

“Take the dam out,” he said, “because it’s not the right dam for climate change.”

 ?? CHASE STEVENS/LAS VEGAS REVIEW-JOURNAL ?? A view of Glen Canyon Dam and Lake Powell at the Glen Canyon National Recreation Area on Wednesday, July 28, 2021.
CHASE STEVENS/LAS VEGAS REVIEW-JOURNAL A view of Glen Canyon Dam and Lake Powell at the Glen Canyon National Recreation Area on Wednesday, July 28, 2021.

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