Lake Powell on the Colorado River fell to its lowest level on record last week, highlighting long-term risks to the reservoir that stores water for delivery to Lake Mead and to Arizona, California and Nevada.
But on a brighter note, a good snowpack season has boosted the latest forecast for Lake Powell to a level not reached in more than two years. The predicted increase will not, however, bring anywhere near enough water to completely reverse declines in the lake's water levels stretching back to 2000.
The lake fell to 3,522.16 feet on Monday afternoon. That broke its previous record low of 3,522.24 feet on April 22, 2022. Records date back to the 1960s when Powell started filling after its creation by construction of Glen Canyon Dam.
Powell, at the Arizona-Utah border, kept dropping last week to 3,521.95 feet Friday afternoon. The lake will drop to as low as 3,520 feet at the end of March before the arrival of spring-summer runoff from melted snows starts to bring the level back up again, federal forecasts predict.
The decline in the past year was expected but is much less severe and will last for a much shorter duration than declines at Powell in the last couple of years, due to federal "drought response actions," said U.S. Bureau of Reclamation spokeswoman Becki Bryant. Those actions included holding back a significant amount of water last year that was scheduled to be released downstream to Lake Mead, and releasing extra water into Powell from Flaming Gorge Reservoir upstream at the Utah-Wyoming border.
Still, Lake Powell has now declined almost 180 feet since hitting a nearly full elevation of 3,697 feet in July 1998. Since 2000, annual Colorado River flows dropped by nearly 20% from 20th century levels due to increasingly arid weather. Mead's level has also plunged in that time, from being nearly full, which would be 1,200 feet, to 1,047 feet Friday evening.
Climate change in the form of continued warming weather has played a major role in the river and lakes' declines, several studies show.
The declines have been severe enough that the Bureau of Reclamation and the seven river basin states, including Arizona, are locked in still-unsuccessful negotiations over how to cut use of river water.
Officials say they're concerned that without dramatic cuts in river water use, Powell could soon drop below 3,490 feet, the minimum level at which its turbines can generate electricity. They're also concerned that if the decline persists beyond that, it could fall to "dead pool" at 3,370 feet — the point at which water can't pass through the dam into the Colorado River downstream.
But the most recent forecasts suggest the river and lakes could be in for a short-term reprieve.
Federal Colorado Basin River Forecast Center predictions, released last week, say Powell should receive 117% of its average April through July runoff this year. The most recent Bureau of Reclamation monthly forecast predicts Powell most likely will rise to 3,564 feet by the end of July before falling again.
The reason for the positive forecasts is unusually heavy snowfall in the Upper Colorado River Basin states of Colorado, New Mexico, Utah and Wyoming in December 2022 and January 2023. While the first half of February was unusually dry, the Upper Basin's snowpack levels still range from 95% to 175% of normal, the forecast center said.
Over the next week to 10 days, forecasters say, the rains and snows that marked the early periods of winter should resume, meaning there will be below average temperatures and above normal precipitation — which would boost river and lake levels more.
As recently as December 2022, federal forecasts found it was possible although not likely that Powell would fall below 3,490 feet for much of 2024. But now, even the bureau's most recent "minimum probable" forecast covering the next two years doesn't show Powell falling below 3,512 feet by January 2025. That "minimum probable" forecast predicts the reservoir level that's lower than 90% of all possible levels.
While these forecasts are positive, "I think people should be reminded, in the last 23 years, we had some big years" in 2005, 2011, 2017 and 2019, said Eric Kuhn, a water researcher and author and former general manager of the Colorado Water Conservation District in Glenwood Springs.
But "we’ve had more dry years than we’ve had big years. What we’re seeing is not unusual. Wet years are part of our overall pattern. We haven't had enough of them," Kuhn said.
This year's wetter weather isn't a reason to pull back on the water conservation measures now being discussed, said Kuhn, adding, "Not one bit, no."
If one assumes that the 21st century average of river water uses and losses, including water delivered to Mexico, isn't reduced, it would take 6 to 7 years of runoff like the river had in 2011 — the biggest runoff year of the 21st century — to refill both Lakes Powell and Mead, said Jack Schmidt, director of Utah State University's Colorado River Research Center.
Recovery of both lakes could be achieved more quickly if the states reduce their water use and their water losses to forces such as evaporation, he said.
A study published by the center in 2022 estimated that if runoff continues to match what's occurred since 2000, Powell and Mead will average about 50% full over the long term. Powell today is 23% full and Mead is 29% full, after river flows fell well below their 21st century average starting in 2018.
"We aren’t ever going to get 6-7 years like this one back-to-back-to-back," Schmidt said.
Sarah Porter, director of the Kyl Center for Water Policy at Arizona State University, said she's had several conversations with people who closely follow the river's ups and downs. They have said they hope one good winter won't cause people "to kick the can down the road" when it comes to cutting water use.
"We keep getting into this danger zone. We need to find permanent solutions to stay out of the danger zone," Porter said.
Photos: The receding waters of Lake Powell, Glen Canyon National Recreation Area
Lake Powell has had several wet years over the past decade, despite the ongoing drought that has dominated the Colorado River Basin's climate since 2000. But in each of the lake's wettest years since 2011, its peak water level has declined from previous peaks.
2011: The lake peaked at 3,660 feet elevation in July.
2017: The lake peaked at 3,634 feet at the end of July.
2019: The lake peaked at 3,621 feet at the end of July.
2023: The lake is projected to peak this year at 3,564 feet at the end of July.
Tony graduated from Northwestern University and started at the Star in 1997. He has mostly covered environmental stories since 2005, focusing on water supplies, climate change, the Rosemont Mine and the endangered jaguar.