Lake Powell, one of the Colorado River’s most important reservoirs, is set to receive 13% of its normal spring runoff, the lowest amount from upstream snowmelt on record, according to a federal forecast Thursday.
The reservoir, located on the Utah-Arizona border, helps pace the flow of water to millions of people, multibillion-dollar industries, hydropower facilities and protected environments in the immense Colorado River Basin. It is also in dire straits: As of Thursday, it held 23% of its capacity. It’s months away from extremely low water levels that would halt hydropower generation at Glen Canyon Dam.
The expected record-low inflows won’t help.
If the forecast is accurate, “it would be the lowest April through July volume on record for Lake Powell,” Cody Moser, a forecaster with the Colorado Basin River Forecast Center, said during a webinar Thursday.
The federal Colorado Basin River Forecast Center tracks conditions in the basin and prepares forecasts used by the federal government to determine how the water for 40 million people in the West should be managed.
Since Oct. 1, about 408,000 acre-feet of water has reached the reservoir. That includes water from the sudden snowmelt triggered by a record-breaking heat wave in March, Moser said.
The expected flow of water into the reservoir this year is about 800,000 acre-feet. There’s still a 50% chance that it could be higher, but the forecasts become more certain with every day that passes, he said.
One acre-foot equals about 326,000 gallons, or the annual water use of two to four urban households.
The basin has just endured one of its worst winters on record. Snowpack was low, temperatures were high and spring precipitation hasn’t been enough to make up for the water deficits.
It is also in the midst of twin crises: historically low water storage and stalled negotiations over how to manage the basin’s vital water supply.
The massive reservoir was designed to hold about 24 million acre-feet. Its storage as of Thursday is a mere fraction of that total, 5.6 million acre-feet, according to data from the federal Bureau of Reclamation, which manages Glen Canyon Dam.
For comparison, Colorado uses about 5.34 million acre-feet of water on average each year, according to the Colorado Water Conservation Board.
The state used an average of 2 million acre-feet of water from the Colorado River Basin between 2021 and 2025, according to data from the bureau. The Western Slope is within the basin’s boundaries, but Colorado River water is transported through tunnels, pipes and canals to almost every corner of the state.
Lake Powell has fallen to historically low levels over the past 20 years in part because of rising temperatures, changing climatic conditions and unyielding human demands.
The lake was just 394 feet deep at the dam as of early May. If the water falls too low, it would be unable to pass through the dam to generate hydropower, a reliable, affordable energy source for communities across the West.
The Bureau of Reclamation projections show hydropower generation could stop as soon as September without intervention. Water managers have started holding back water in Lake Powell and releasing water from upstream reservoirs, like Flaming Gorge on the Wyoming-Utah border, to protect the dam’s infrastructure and continue generating power.
An expiring set of reservoir management rules also contributed to the West’s water storage crisis. The rules, established in 2007, allowed the reservoir to be drained even in dire drought years, and officials’ efforts to respond failed to restore the reservoir’s storage.
Those rules expire this year, and negotiations to replace them have been largely stagnant for months. The new set of rules must be in place by Oct. 1.
During the webinar Thursday, Moser paused and took a breath.
“Really no good news this winter.”