Colorado River snowpack takes major dive; streamflow projections lowered

Yahoo

19-04-2025

LAS VEGAS (KLAS) — A late-season rollercoaster ride this year turned into a steep decline for snowpack levels that feed the Colorado River.
Since April 9, when snowstorms pushed snowpack from 91% to just over 100% in a single day, conditions have changed dramatically and levels have fallen to 70% of normal as of Friday, April 18. That's concerning for 40 million people who rely on the river for water.
The black line in the graph below shows this year's snowpack levels, or more technically, snow water equivalent (SWE) levels, in the Upper Colorado River Basin.
Projections from the federal government have been adjusted, showing less water flowing into Lake Powell, the nation's second-largest reservoir. Streamflow at Lake Powell is now expected to be about two-thirds of normal this year (67%). Just two weeks ago, projections showed it would be about three-fourths of normal (74%).
The one-day flirtation with normal snowpack levels is a distant memory now.
And all of that is happening before water gets as far as Lake Mead — the nation's largest reservoir, where Southern Nevada gets 90% of its water.
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'This has been another — unfortunately — classic year of the impact of climate change where high up in the Rocky Mountains in the headwaters of the Colorado River, you have slightly below average or average snowpack, which seems good on paper,' John Berggren, regional policy manager for Western Resource Advocates, said on Wednesday.
'But for a variety of reasons, that's not translating to average runoff for the Colorado River,' he said.
Berggren, based in Boulder, Colorado, has been studying water conditions in the West for 15 years. He has a Ph.D. in water policy and leads Colorado River work for the nonprofit.
While the steep plunge in snowpack is troubling, there's something else on Berggren's mind: There's no agreement in place yet for how the river will be managed when guidelines expire next year.
The last major development in that process came on March 7, when officials from lower basin states (Nevada, Arizona and California) urged the Trump administration to set aside a decision by the outgoing Biden administration. Water officials said the U.S. Bureau of Reclamation made a mistake by not including an option that would consider infrastructure changes at Glen Canyon Dam.
'I don't think decision makers are seriously considering enough, the fact that Glen Canyon Dam needs to be completely re-engineered,' Eric Balken, executive director of the nonprofit Glen Canyon Institute, said in an April interview.
If the surface of Lake Powell drops below 3,490 feet above sea level, the dam would be incapable of releasing enough water to meet requirements under the Colorado River Compact, commonly referred to as the 'Law of the River,' according to an analysis released in 2022.
Lake Powell is currently 33% full, at 3,558 feet. Projections indicate the reservoir's low point over the next two years will be about 3,549 feet. That's about 33 feet below it's projected high point of 3,581 feet.
The federal government has not replied publicly to the states' request for a 'do-over.'
'Unfortunately, politics gets involved and each upper and lower basin states have their negotiating positions. But we all here in the West rely on this river,' Berggren said.
'You're downstream, we're upstream, we all rely on this river, and so not having an agreement is a big challenge and potentially harms the river and the people who rely on it,' he said.
'We need the states to come together, we need them to agree, need them to find compromise, find ways to reach an agreement where we can all move forward with a healthy flowing Colorado River,' Berggren said.
A report released April 15 by the Bureau of Reclamation shows only slight adjustments to expected reservoir levels over the next two years despite the expected reduction in streamflow.
But rewinding to 2024, the projections are quite different from reality. (Below, pages from the Bureau's 24-month study showing projections for Lake Mead and Lake Powell)
The typical low-water mark for Lake Mead comes in July each year. For this year, that's expected to be 1,053.58 feet. A year ago, the projected level for July 2025 was 1,048.24 feet, so the lake is now expected to be more than 5 feet higher than projections from last year.
Projections for Lake Powell are not as optimistic. Lake Powell's low-water mark typically comes in April, just before spring runoff begins and reservoirs build up. For this year, that's expected to be 1,062.68 feet — about 9 feet lower than projections from last year (3571.24 feet).
Getting nervous about lake levels isn't going to solve anything, but inaction could be a far more damaging course. Berggren echoed comments that have been provided some motivation for leaders to get ahead of the decision before it's too late.
'There is almost universal agreement that litigation should be the last resort by all means. If the states can't reach an agreement, and this thing ends up in the Supreme Court, you're looking at maybe a decade or longer for the Supreme Court to make a decision,' Berggren said.
'And who knows … the only thing we know from that decision is there will be winners and losers, and we don't know who the winners and losers would be. So it's a huge risk to the states, it's a risk to water users, it's incredibly expensive, incredibly time-intensive process to potentially not know where you're going to end up,' he said.
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