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'Dead pool' at Lakes Mead and Powell a real possibility, says Arizona water chief
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'Dead pool' at Lakes Mead and Powell a real possibility, says Arizona water chief

“Dead pool,” a condition in which reservoirs fall so low that water cannot be pulled from them, is a real possibility in Lakes Mead and Powell on the Colorado River, Arizona’s top water official recently told a private conference, according to a published report and several people who attended.

They say that Tom Buschatzke, director of the Arizona Department of Water Resources, told the Scottsdale gathering on water law late last month that real fears exist among officials that Powell and Mead could fall to dead pool if not enough is done to arrest their recent sharp, continuing declines.

Federal forecasts for both reservoirs for the next five years look grim, but they do not predict anything close to dead pool levels. However, recent drying trends make some experts wonder if the official forecasts are too optimistic.

If Mead and Powell were to eventually become inaccessible for human use, that would deprive tens of millions of people living in the Colorado River Basin’s seven states of water used for drinking, irrigation and industries. By the time Mead and Powell were to reach dead pool levels, they would have also long since been unable to generate electric power through Hoover and Glen Canyon dams, both of which serve power to millions of people around the West.

Buschatzke told the conference that cooperation among the three Lower Colorado River Basin states — Arizona, Nevada and California — is focused on preventing such declines. The states’ water representatives and tribal representatives are meeting informally and privately to discuss what steps might be taken to save water for the reservoirs to keep them from falling too low.

Those meetings are happening in advance of formal negotiations that are expected to start at a later, still-uncertain date.

Stark change in tone

Buschatzke’s comments about the possibility of dead pool were unusually candid for a top water official in this region. They came just 10 days after federal officials declared on Aug. 16 the first shortage in water deliveries by the Central Arizona Project, which gets water from the river and Lake Mead.

Official warnings about the lakes dropping that low had been heard during previous dry spells in the mid- and late 2010s. But such rhetoric died back as wet periods in 2015, 2017 and 2019 brought the Colorado and its reservoirs short-term relief.

Up until very recently, in fact, Buschatzke and other Arizona water officials seemed relatively optimistic about the reservoirs’ near-term future. That largely stemmed from the adoption of a 2019 drought contingency plan that established a series of increasingly severe cuts in water deliveries from the river in the seven river basin states.

The plan’s purpose was to stabilize the reservoirs and keep them from falling to critically low levels, while acknowledging some shortages are inevitable. When asked during that time to comment about continued declines in reservoirs or the potential for bigger, future water shortages, Buschatzke and others said these situations were expected and provided for in the 2019 drought plan, and they were not alarmed by them.

The past two years, however, have seen repeated instances in which runoff levels into Lake Powell, and water elevations at both reservoirs, repeatedly fell well below levels previously forecast by climate experts at federal agencies.

Most important, there have been back-to-back, near-record low amounts of spring and summer runoff into Powell from the Northern Rockies that provides the lion’s share of the river’s annual flows. These flows eventually find their way to Lake Mead to serve the Central Arizona Project, which provides drinking water to Tucson and Phoenix and irrigation water to Central Arizona farmers.

The U.S. Bureau of Reclamation has declared the first shortage of CAP deliveries will start in January 2022. The bureau’s forecasts for the next two to five years are bleaker still, raising possibilities of more severe cuts in Colorado River deliveries and of a still unlikely but hardly unthinkable cutoff of electricity production from Glen Canyon Dam at Lake Powell.

Buschatzke’s comments were reported in the Western Farm Press, a trade publication covering agricultural issues in Arizona and California. Buschatzke made them at an Aug. 26 appearance at an Arizona Water Law Conference sponsored by CLE International, a business-backed nonprofit group that offers attendees continuing education credits in professions such as lawyers, appraisers, real estate brokers and realtors.

Buschatzke did not say in his talk how soon he thought the lakes could hit dead pool, or why he thought dead pool was possible.

The director’s office said he was not available for questions last week from the Arizona Daily Star about his remarks.

Dead pool did come up briefly at a recent meeting of the CAP governing board, however. Chuck Cullom, CAP’s Colorado River programs manager, said at the Sept. 2 CAP meeting that a few scenarios exist in Bureau of Reclamation computer-based forecasts that show Lake Powell approaching dead pool levels between now and 2026.

But the odds are only 1.5% of each of three such scenarios becoming reality by 2026, Cullom said.

ADWR spokespeople declined to confirm the accuracy of the remarks attributed to Buschatzke by the Farm Press. They said they had not yet obtained a recording of his comments from the event’s sponsors to verify what the director said.

But three people who attended the conference told the Arizona Daily Star they heard Buschatzke’s dead pool warning. Two are Cynthia Campbell, the city of Phoenix’s water resources advisor, and Brian Biesemeyer, executive director of the Scottsdale Water Department. A third who confirmed hearing such comments spoke on condition of anonymity.

Next three years are critical

The very bad runoff of the past two years is a warning signal to the basin, said John Fleck, a prominent University of New Mexico water researcher and author of two books about the river. He noted that from 2000 to 2005, Lake Powell dropped almost 100 feet.

“What we always have known is that a repeat of the drought of the first five years of the 21st century would be devastating. Whether it would be dead pool is a technical question for the modelers. But we clearly know a series of four or five years like 2001-05, we’re not ready to handle that,” said Fleck, head of UNM’s Water Resources Program. “We’ve now had the first two of those years.

“If we have two more years like that, we have really serious problems. If this happens right now, we don’t have the water use reduction tools across the basin to make cuts that quickly,” he said.

If the next three years are as bad as the past two years, marking a rerun of the early 2000s, “both reservoirs will be at dead pool,” said Brad Udall, a Colorado State University water researcher, last week.

From 2000 through 2004, the Colorado River’s entire reservoir system lost almost 25 million acre-feet of storage compared to the 47 million acre-feet that existed in 2000, he said. As the two big reservoirs keep dropping, they are likely to be carrying as little as 15 million acre-feet by next spring, said Udall.

Three or four more years like the last two would almost certainly drain them, even with the water-usage cuts approved under the drought plan and under earlier operating guidelines for the river, he said.

A number of officials and academics said Buschatzke’s reported comments underscore the need for cooperation, compromise and sacrifice among the federal government and all parties managing the river in the seven Colorado basin states.

“It’s important for him to talk about these things that are possibilities. Otherwise, no one is motivated to do anything about them,” said Sarah Porter, director of Arizona State University’s Kyl Center for Water Policy. “I’m glad that Director Buschatzke is drawing attention to the need for us to take steps.”

Scottsdale’s Biesemeyer said: “I believe we all have a common goal — to keep the Colorado River supply healthy in order to sustain our communities into the future. But it will take sacrifice, and it will take compromise.

“We can’t control the weather, but we can control how we use water. We want to encourage residents to use water wisely and efficiently to better secure our water for the future,” Biesemeyer said.

Lakes lost 25% of water in one year

At Lake Mead, the Bureau of Reclamation considers dead pool to be 895 feet.

That’s more than 170 feet below the 1,067-foot level where the lake at the Arizona-Nevada border stood Friday.

At Powell, at the Arizona-Utah border, dead pool is at 3,370 feet, nearly 180 feet below that lake’s elevation of about 3,549 feet as of Friday, the bureau says.

But the river’s situation in recent years has been far more dire than the federal government’s predictions.

At Powell, for instance, water levels have fallen 66 feet since the end of September 2019. Mead’s water elevation has fallen 17 feet in the past year after staying largely stable from September 2019 to September 2020.

Two years ago this month, the U.S. Bureau of Reclamation predicted the most likely outcome for Lake Mead was for it to drop only 2 feet by the end of September 2021. For Powell, federal forecasters had in September 2019 predicted it would drop 21 feet by now.

These sharp declines have come despite reasonably good winter snowpack levels in both years in the Northern Rockies. This year, for example, winter snowpack in the entire Upper Colorado River Basin was 82% of normal.

The federal Colorado River Basin Forecast Center predicted in January 2021 that runoff in the river into Powell from April to July would be 53% of normal. It ended up at 26% of normal, the third-lowest spring-summer runoff into Powell on record.

Soil moisture in the upper basin was the lowest on record this spring, after last year’s hot and dry summer and fall dried up much of the moisture provided by a good winter 2020 snowpack. April 2021’s precipitation in the Upper Basin also was the lowest on record for the month, said Ashley Nielson, a senior hydrologist for the river basin forecast center.

As of late August, the Colorado’s entire reservoir system held 21.43 million acre-feet of water. That’s about 7 million acre-feet, or 25%, less water than the reservoirs held a year ago, CAP’s Cullom told the project’s governing board at its Sept. 2 meeting. An acre-foot is enough to serve four Tucson households with water for a year.

Cullom told the board, however, that there is some “cheery news.”

Because of this summer’s excellent monsoon season and other factors, “I’m pleased to report” that Lake Powell recently received an extra 100,000 acre-feet of water than had previously been expected, he said.

Now, the total flow into Powell from October 2020 through September 2021 is expected to be the third-lowest on record, when it had previously been predicted to be the second-lowest total, year-round flow on record, he said. Overall, the flow for what’s known as the “water year” for 2020-21 still will be one-third below normal, Cullom told the board.

When you look at the 22-year period on the river since 2000, it’s clear that there was no comparable period of low flows during the entire 20th century, said Colorado State researcher Udall, a Tucson native.

The river’s average annual natural flow is down 19% for the period of 2000 to 2021 compared to that of the 20th century, he said. Since 2000, the river has had half as many high-flow years and 2½ times as many low-flow years as it had from 1906, when records started being kept, to 2000, he said.

“This is by far the worst 22-year period of recorded history back to 1906,” he said of the Colorado River flows.

Deeper CAP cuts not seen in near-term

Looking two years ahead, the Bureau of Reclamation predicts that Mead will most likely drop to barely above 1,050 feet by the end of 2022. That’s just high enough for the Lower Basin states to avoid a deeper CAP shortage than the one that will start next year. A deeper shortage would cut more water supplies to several tribes and to many Phoenix-area cities, although not to Tucson.

By June 2023, the bureau predicts that Lake Mead could, in the worst-case scenario, fall to 1,030 feet. It was that prediction that triggered the states and the feds into a new round of meetings to try to come up with ways to take less river water.

Looking ahead to 2025, the bureau predicted in June that there’s a 38% chance that Lake Mead will drop below 1,025 feet that year. That would require still larger cuts for tribes and Phoenix-area cities and the first cuts in Tucson’s supply, although only 11% of Tucson’s total. For the same year, the bureau predicts a 21% chance that Mead could fall below 1,000 feet for at least one month.

For Lake Powell, the bureau forecast a 79% chance that it would drop below 3,525 feet sometime next year — the level at which officials would first get concerned about Glen Canyon Dam’s ability to generate electric power.

By 2024 and 2025, Powell is seen as having a 16% and 17% chance, respectively, of falling below 3,490 feet, where it’s known the dam cannot generate power. When the bureau looks at what it calls the “minimum probable” scenario for river flows, the lake could fall below 3,490 as soon as January 2023.

Consequences of inaction ‘unimaginable”

Asked to comment on Buschatzke’s remarks, Phoenix water official Campbell said: “Nobody knows what’s going to happen, but the realm of possibility we’re looking at is not acceptable. All the things that are possible that could happen are not all things that we could deal with. Nobody’s in a position to deal with dead pool.”

“It’s safe to say that we collectively, the region, is looking at some difficult possibilities based on what’s happening with climate change, and I don’t think there are necessarily silver bullets,” Campbell added. “It’s going to take some real effort and creativity. There’s no easy solutions.”

She took heart, however, at comments made at the conference by Chris Harris, director of the Colorado River Water Board of California, who spoke on a panel with Buschatzke. Campbell quoted Harris as saying, “’We’re committed to doing whatever we need to do with Arizona and Nevada to make this happen, to protect Lake Mead from dead pool.’”

Cooperation among all of the Basin States is the only way the seriousness of the Colorado River situation can be addressed, said Warren Tenney, head of the Arizona Municipal Water Users Association in Phoenix.

“It will not be pain free, but Reclamation and the Basin States understand taking no action is not an option,” said Tenney, a former top official for the Metro Water agency in the Tucson area. “It’s the old adage: You prepare for the worst and hope for the best. It’s the scout motto — be prepared.”

Tucson Water officials, who have been optimistic about the city’s ability to handle even major CAP cuts, remain so despite Buschatzke’s warning about the possibilities of dead pool.

Assistant City Manager and former Tucson Water Director Tim Thomure serves on an Arizona-based committee working on updating and revising operating guidelines for the reservoirs, including those in the drought contingency plan.

“With dedication to proper long-term water resource planning, Tucson Water is prepared for any scenario on the Colorado River over the coming decades,” the utility said in a statement.

“In the event of rapidly deteriorating conditions on the Colorado River system, the city will have an active role working with the other members of the committee to take the steps necessary to secure the long-term health of this critical resource for all of Arizona.”

Buschatzke’s concern about dead pool is one reason that Kathryn Sorensen, former Phoenix water director, “worked hard” a few years ago to persuade the Phoenix City Council to invest $500 million in the transmission mains and pump stations that can deliver Salt and Verde river supplies to areas of Phoenix that now depend on Colorado River supplies.”

“With this in place, Phoenix can withstand dead pool,” said Sorensen, now research director at ASU’s Kyl Center. “The risk of inaction is high, and the consequences are unimaginable.”

Contact Tony Davis at 520-349-0350 or tdavis@tucson.com. Follow Davis on Twitter@tonydavis987.


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Federal officials say it's likely Lake Mead at the Nevada border will be low enough at the end of 2021 to trigger the first major cutback in CAP deliveries to the Arizona's parched midsection.

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