2024 outlook for Colorado River less rosy after banner year

It was a banner water year for the Colorado River Basin, with water use in the three Lower Basin states including Arizona way below normal and water supplies in the river running well above normal in 2023.

The outlook for 2024 is cloudier. While approved and planned water conservation efforts are likely to keep water demand below normal, the river’s water supply forecast for the year is much less rosy, though it’s too early in the season to know how it will turn out.

For 2023, heavy river runoff along with much bigger water conservation efforts helped push the water levels at Lakes Mead and Powell much higher than they were a year earlier.

Early in the year, water levels in both reservoirs were so low after three straight bad years that the federal government was proposing drastic water use curbs for the Lower Basin states that also include California and Nevada.

But by May, river runoff and reservoir levels were improving fast enough that the three states were able to produce a substitute, scaled-back plan. Now headed for almost certain federal approval, it will cut water use in the region by 1 million acre-feet a year for three years. That compared to the feds’ earlier plan that could have cut up to 3 million to 4 million acre-feet a year.

Now, however, the early projections for 2024 are for spring and summer runoff well below normal. In mid-December, such runoff into Powell was projected to be 75% of normal runoff between 1991 and 2020 by the Colorado Basin River Forecast Center.

The center’s late December forecast was even more pessimistic, projecting runoff into Powell from April through July 2024 at 65% to 70% of normal. The center cited below-normal soil moisture and snowpack conditions as the basis for its forecast.

For the entire period October 2023 through September 2024, known as a “water year,” runoff into Powell is now forecast to be 79% of normal levels.

The total annual runoff forecast into Powell for that October 2023 through September 2024 span dropped by 1 million acre-feet, just between November and December, U.S. Bureau of Reclamation records show. The forecasted flow for that period has now dropped about 1.8 million acre feet since October 2023.

Water levels at Powell and Mead are still most likely to be manageable in both 2024 and 2025, with no risks of either lake falling so low that it won’t be able to deliver electricity to the dams’ 13 million total power customers, the reclamation agency has said.

But in what federal officials call the December study’s “minimum probable forecast,” one with a 90% chance of being exceeded, water levels at Mead could fall to record low levels by fall 2025: 1,036 feet.

Water levels at Powell could drop by then to as low as they fell in early 2023, 3,521 feet. Back then, alarm bells were ringing about potentially catastrophic river conditions occurring within two years — a concern that evaporated as winter snowfall accelerated.

These forecasts are contained in the bureau’s newest 24-month study. It projects likely future conditions in the river’s reservoirs every month, up to two years in advance.

In 2023, extremely heavy snows and rainfall across the river basin sent river runoff soaring. The 2023 spring-summer runoff into Powell turned out to be 166% of normal. Annual river flows were the second highest on record since 2000.

Streamflow in tributaries to both Lake Powell and Lake Mead was also extraordinary earlier in the year.

In 15 Upper Colorado River Basin streams — lying upstream of Lake Powell — spring and summer runoff reached 105% to 212% of normal, when averaged over the past 32 years. Five Lower Basin streams fared even better, carrying runoff ranging from 187% to 444% of normal.

Conservation

Plus, the three Lower Basin states, in particular, helped river flows by ratcheting down their water use tremendously in 2023. Arizona, California and Nevada used about 5.8 million acre-feet in 2023. That’s 1.7 million acre-feet less than they’re legally entitled to use and the lowest such total in this basin since 1983.

Water use reductions in 2023 were particularly pronounced for Central Arizona Project customers, including the cities of Tucson and Phoenix, and for those served by the Metropolitan Water District of Southern California. The district is a wholesale water supply agency serving six Southern California counties.

In 2023, the CAP was expected to take about 832,000 acre-feet. That’s about 150,000 acre-feet less than it took in 2022 and about 500,000 acre-feet less than it took in 2021. The Metropolitan district was projected to take about 661,000 acre-feet in 2023, almost half a million acre-feet below its 1.1 million use in 2022.

Local conservation is definitely a factor in the year’s water use reductions. The U.S. Bureau of Reclamation signed contracts in 2023 with 18 Lower Basin water users — 14 in Arizona and four in California — to conserve about 1.54 million acre-feet annually through 2026. To compensate them for taking less water, the feds will fork over $651 million of the $4 billion that Congress appropriated for drought relief in the 2022 Inflation Reduction Act.

In Arizona, Tucson has agreed to conserve 111,000 acre-feet through 2025 in return for $44 million compensation. Phoenix will conserve 150,000 acre-feet in the same period for $60 million. The biggest Arizona cutback will fall upon the Gila River Indian Community in Central Arizona — 341,000 acre-feet for $136 million compensation.

In California, the Metropolitan Water District and the Palo Verde Irrigation District will together conserve 351,000 acre-feet for $140 million. More cuts are now being negotiated with water users — the bureau has agreed to pay $2.3 million total to support conservation efforts over three years.

But not all the conservation that occurred in 2023 is guaranteed to last. The Metropolitan Water District, for instance, saved so much water during the year “due to record low demands in our service area thanks to water-efficiency efforts across Southern California and availability of other supplies,” said spokeswoman Rebecca Kimitch.

While conservation was clearly a factor in those low demands, so were unusually heavy storms in Northern and Southern California early in the year, said Jeff Kightlinger, a former Metropolitan general manager. The Northern California rains and snows provided more water for the district’s customers, while Southern California rains reduced peoples’ need to turn up their taps, he said.

Back to homepage

Subscriber Login

Keep reading with a digital access subscription.

Subscribe now

Looking ahead to 2024, water demands “will similarly depend on conservation levels in Southern California and availability of other supplies,” Kimitch said.

“Metropolitan is committed to doing additional conservation. Based on their planning and structure, I have full confidence in their ability to do conservation,” said Kightlinger, who now works as a consultant for Southern California’s Imperial Irrigation District.

But he added, “It’s not likely to rain (as much in 2024) in both Northern California and Southern California. There will not always be that surplus in Northern California to rely on. That will also push up demand in the future.”

Drying again

The basin’s weather in the fall was far less generous than in early 2023.

Soil moisture in the open lands of the river basin — a major factor driving river runoff — ranged from near to below normal, says the federal Colorado Basin River Forecast Center’s latest forecast, from Dec. 13. The summer monsoon season was much drier than normal in most of the river basin, except for northern and far western Arizona.

Then, precipitation in October and November averaged 73% of what was normal from 1991 through 2020 in 12 spots upstream of Lake Powell in the Upper Basin. It was far worse in the Lower Basin, ranging in five areas from 34% to 52% of normal in those months.

Snowpack in areas above Lake Powell has been 73% of normal since Oct. 1. But it was virtually nonexistent as of mid-December in much of the Lower Basin.

No snowpack was measured in that time in the Verde River Basin above Phoenix and 3% of normal snowpack occurred in the Upper Gila River Basin, above Coolidge Dam. It was 32% of normal in the Salt River Basin above Phoenix.

“One thing we have to remember is it’s quite early in the season,” observed Vineetha Kartha, the Central Arizona Project’s Colorado River program manager. “One thing that we noticed was that the drop in projections for the runoff, it declined precipitously in mid-November and December. We think it’s due to soil moisture conditions.”

Also, the federal river forecast center’s study was done in early November and released on Dec. 13, she noted. Since then, a lot of new conservation agreements have been signed by cities, irrigation districts and other water users and the Bureau of Reclamation.

“Those were under negotiation and not (accounted for) in the latest 24-month study” by the bureau, she said.

“All it would take is one or two big storms to turn things around,” said Eric Kuhn, an author, researcher and retired general manager of the Colorado River Water Conservation District in Glenwood Springs, Colorado.

The last three unusually wet years in the Colorado Basin — in 2011, 2017 and 2019 — were all followed by very dry years. Most notably, the 2019 wet year was followed by three straight dry years ending in 2022.

But, “I don’t know you have enough of a statistical sample to make any real judgments — another dry year is not inevitable this year,” Kuhn said. “But if by mid-January, we’re still in this position, I think it’s going to be hard to recover to average conditions.”

“So far, so good”

Another water researcher, Jack Schmidt, a retired Utah State University professor, has found some good news from fall 2023’s otherwise bleak track record.

In an early December blog post titled “So far, so good,” Schmidt reported that by the end of November, water storage in all Colorado River reservoirs had dropped enough from its mid-July peak that the entire river basin had used 21% of its exceptional spring-summer runoff.

That’s the slowest reservoir drawdown in this period in all but one of the past 10 years, he wrote.

This is a sign that the water conservation efforts across the Lower Basin this year may be working, Schmidt wrote.

Reservoirs, he wrote, “are the ultimate buffer between water use and a water crisis, especially during extreme dry spells, such as occurred in 2002-04 and 2020-22.”

“The question is, ‘Is that going to be good enough?’ That’s what I can’t tell you,” Schmidt said of the reservoirs’ subdued water level declines, in a mid-December interview with the Star. “We are making better progress than we have in other years, the past 10. But that doesn’t mean in absolute terms we are good enough.”

He noted in his blog that water levels at Mead and Powell remain extremely low, now 34% and 36% full respectively. The total water storage in all the river’s reservoirs is now at around the same place as it was in early May 2021, he wrote. At that time, the most recent very dry conditions in the lakes were accelerating on their way to a peak in winter 2023.

“We are still in a crisis,” Schmidt, retired director of Utah State’s Center for Colorado River Studies, told the Star.

He concluded his blog post by saying, “Let’s hope for a good 2023/2024 winter and spring snowmelt.”