Lake Powell reaches highest level in more than 3 years

That has happened even though this year’s runoff into the lake will be below average.

As of Thursday, Powell stood at 3,586 feet, more than 60 feet higher than in early 2023. At that time, it had fallen to a record low level and was on the edge of falling so low that Glen Canyon Dam wouldn’t be able to generate electricity.

The lake is now well out of danger of falling that low in the near future. But some scientists point out that since the lake is at roughly the same level as when it began its sharp decline back in 2021, a couple of consecutive dry years could once again lower it to near-crisis levels.

Powell is now 42% full, compared to 23% in February 2023, 35% late last year and 37% on June 1.

The lake’s higher levels have reduced the risk of short-term, severe cutbacks in water deliveries from Powell to Lake Mead and from there to the three Lower Basin states of Arizona, California and Nevada. Powell is in northern Arizona and stretches up into southern Utah.

Powell’s levels are high enough that some recreational facilities that were closed due to low water in 2022 have since reopened, including a few boat marinas and a ferry linking two marinas lying 3 water miles apart by a 25-minute boat ride. Run by the state of Utah, the ferry taking vehicles from Hall’s Crossing Marina to the Bullfrog Marina at Powell’s east end reopened July 4th, although officials say it will only stay open as long as the lake is above 3,575 feet.

While 2023 brought way above average snowpack and river runoff, this past winter and spring brought good but not outstanding snowpack.

Despite that, there are several reasons the lake has kept rising.

A crucial factor is that agreements many Arizona and California water users made with the federal government saved considerable amounts of water in the past year, three longtime Colorado River experts said.

The conservation slashed Arizona’s take from the Colorado River to its lowest level since 1991 and Nevada’s to its lowest level since 1992, New Mexico author and water researcher John Fleck posted on his Inkstain blog Thursday. California’s Colorado River water use in 2023 appeared to be its lowest since the late 1940s, Fleck wrote.

“Amid all the angst and rhetoric, it is easy to miss the salient fact” that Lower Basin water users have reduced their take on the Colorado River substantially since the early 2000s, Fleck wrote.

“To be clear, the use in the late 1990s and early 2000s was unsustainably large,” Fleck wrote. “Praise is due for shrinking Lower Basin use, but the praise should be tempered by the fact that they didn’t do it until the reservoirs had dropped to scary low levels.”

The states did such a good job of using less water that the river’s reservoirs as a whole gained total storage despite the lower-than-average spring-summer runoff, said Jack Schmidt, director of Utah State University’s Center for Colorado River Studies.

“If we had not done such a good of conserving, we’d have lost more storage and been going in the wrong direction,” Schmidt told the Arizona Daily Star.

But that doesn’t mean the lake is out of danger of falling back into crisis mode in the future if we get another run of consecutive dry years, he and another expert said.

The amount of water stored in Powell and the rest of the river’s reservoirs, while significantly higher than a year to 18 months ago, has not returned to the typical reservoir storage between 2005 and 2019, Schmidt said. Indeed, the lake is now at about the same level as it was in early 2021, shortly before it started to precipitously decline for the next two years.

“So we are very much still on the edge. We’re not as close to the edge as we were last year. But we are still very much on the edge,” Schmidt said.

We don’t know what the upcoming La Niña winter-2024-25 season forecasted by many weather experts will be like, said David Wegner, a retired U.S. Bureau of Reclamation engineer. This past winter was an El Niño winter, with excellent rainfall in the Southwest and good snowpack in the Rocky Mountains.

But often, La Niña winters bring dry conditions to the Southwest and to the entire Colorado River Basin, sometimes drastically slashing river flows.

“If anybody tells you we are out of the woods they are smoking something,” said Wegner, now a National Academy of Sciences board member. “We just had a couple of good years. What the bureau and the states have implemented with the 2019 Drought Contingency Plan and their (current) conservation efforts have helped protect the water supply coming into Lake Powell.”

Most long-term forecasts for Colorado River flows continue to predict declines due in part to hotter weather and human-caused climate change. All seven river basin states are now locked in very difficult negotiations to try to come up with a long-range plan to make further reductions in total river water use.

As of now, the federal Colorado River Basin Forecast Center predicts that April through July runoff into Powell on the river from the Upper Colorado River Basin will be 84% of normal. That’s a far cry from the 166% of normal spring-summer runoff the lake received in 2023.

But it’s better than what the federal agency had forecasted in late December — 65% to 75% of average — or as recently as June 1st — 80% of average.

First of all, the snowpack in the mountains of the Upper Basin was generally good during the winter and spring, supplying the river with decent runoff.

Second, because last year saw such good snowfall and river runoff into the lake, the soils in the mountains that feed the river’s tributaries that supply river water were already lush with soil moisture. That means the melting snows in the mountains were able to keep running off into the river rather than being soaked up by soil, Wegner said.

That was a complete reversal of what happened to the Colorado from 2020 through 2022. In those dry years, the soils were so parched that they then soaked up a lot of the melting snows from the mountains, depriving the Colorado and its tributaries of a key source of water supply.

On top of all that, in June, precipitation, mostly rainfall, was 150% of normal in the entire Upper Basin and 250% of normal in several Southwest Colorado River Basins.

That rainfall by itself boosted the runoff forecast and caused Powell to rise 4 feet higher than it would otherwise have reached, said Jeff Lukas, who runs a climate research and consulting firm in the Denver area.

From May 1 until now, the lake rose 27 feet, matching the average range of lake level increases of 20 to 30 feet in a normal runoff year. That’s the normal peak runoff season into Powell, when melted snows and other runoff make their way downstream from the mountains, a Bureau of Reclamation official told the Star.

Overall, the river basin’s reservoirs were able to gain about 2.5 million acre-feet more water for storage from April 24 through July 6 of this year — “a very modest storage increase,” Schmidt said. That was about 25% of last year’s gain, he said.

Stressing that the basin is making “great strides” in conservation, Schmidt noted that average annual river water use, after accounting for return flows of water to the river by farmers, was about 13 million acre-feet from 2021 through 2023. The average was 13.9 million annually in the previous 10 years and even more before that, he said.

At the same time, despite last year’s banner runoff year, the Colorado has averaged only about 12 million acre-feet a year of total flows since 2000, leaving a deficit that the seven basin states are now trying to figure out how to make up.

If we had three more bad years of river flows like in 2020 through 2022, “we would absolutely be in a major five alarm fire,” Schmidt said.

But because of this past year’s conservation efforts, it wouldn’t be as bad of a water crisis as it otherwise would be, he added.

Looking ahead, the Bureau of Reclamation’s latest monthly forecast for Colorado River reservoir levels predicts that Powell will most likely decline gradually from now until next spring, then rise again by summer 2025 to even higher levels than those of today.

But the computer modeling the bureau uses to make that forecast assumes we’ll get average precipitation and runoff, rather than looking at “the upper and lower bounds” of possible river flows, Wegner said.

“That is why they (the forecasts) are often wrong,” Wegner said. “They take an average, but especially with climate change, El Niño and La Niña years, you see different things going on than the average.”