Colorado

Climate change will reduce streamflow in the upper Colorado river basin as groundwater levels fall, study finds

Published

2 years ago

May 23, 2024

Climate change will reduce streamflow in the upper Colorado river basin as groundwater levels fall, study finds

The illustration shows historical atmospheric and environmental water loss and contributions. Credit: Caroll et al

The Colorado River makes life possible in many Western cities and supports agriculture that sustains people throughout the country. Most of the river’s water begins as snowmelt from the mountainous watersheds of Colorado, Utah, and Wyoming, and a warming climate will drastically reduce these streamflows, new research finds.

Researchers from Desert Research Institute (DRI), USGS, and Lawrence Berkeley National Laboratory teamed up for the new study, published May 23 in Nature Water.

By applying warming to historical conditions for the East River in Colorado and using computer simulations to observe the impact on streamflow and groundwater levels, the scientists found that groundwater storage would fall to the lowest known levels after the first extremely dry year and fail to recover even after multiple wet periods. When groundwater levels fall, streamflows are drawn into the water table instead of contributing to Colorado River flows.

“We found that groundwater matters a lot,” says Rosemary Carroll, Ph.D., DRI research professor of hydrology and lead author of the study. “Even with historically observed wet periods in the model, the groundwater can’t come back from a single dry water year under end-of-century warming.”

The Colorado River has been in a drought state for decades, creating tensions around water rights throughout the Southwest. Scientists have been perplexed by falling river levels even in relatively wet years—in 2021, the Upper Colorado River Basin reached 80% normal snowpack but delivered only 30% of average streamflow to the river.

The study authors wanted to examine how warming in mountain basins may be contributing to this phenomenon. Increased temperatures alter the balance between snowfall and water availability in a number of ways, including more snow evaporation (known as sublimation), more precipitation falling as rain instead of snow, and more frequent melting throughout the winter.

Past research has largely overlooked the role of groundwater and how it may buffer, or intensify, streamflow loss from climate change.

“I’m very interested in the relationship of groundwater contributions to streamflow—that has been a running theme in my research for a long time,” Carroll says. “A lot of studies indicate that in the short term, groundwater release to streamflow will help buffer drought impacts, but before this study, we didn’t have any knowledge on what that would mean over the long haul.”

Rising temperatures will significantly reduce streamflow in the upper Colorado river basin as groundwater levels fall, new research shows — The graphic illustrates how declining water tables under climate change would decrease streamflows. Credit: Jeremey Snyder, from Carroll et al.

The study authors used the East River as the focus for the research because it is representative of the headwaters of the Colorado River, as well as the significant weather and water monitoring infrastructure available. Ground observations and airborne mapping measure snowpack depth and density, streamflow, plant cover, and groundwater levels, among many other measurements throughout the watershed.

Historical data from 1987 to 2022 was used to create the computer model. The research team then applied 4 degrees Celsius of warming to this time period in two ways: for one simulation, warming was applied constantly across time, while in subsequent simulations, warming was applied to each season independently.

The approach allowed the scientists to examine the differing impacts of warming between seasons. Four degrees Celsius is representative of the projected climate at the end of the century based on observed warming of approximately 0.4 degrees Celsius per decade in the watershed. The simulation doesn’t account for likely changes in vegetation over the same timeframe.

The study showed that consistently warmer temperatures resulted in sharp declines in groundwater levels that were unable to recover to historical average levels during wet periods. Isolating the warming seasonally demonstrated the strong impact of warmer summers on water table declines, as the atmosphere increases evaporation rates, plants increase their water uptake, and soils dry out. The largest declines in water table elevations occur in the subalpine forests where conifer forests are most dense.

“As the groundwater level drops, you lose more streamflow to the water table,” Carroll says. “When precipitation is low, the East River stops flowing for a portion of the summer. Of course, this would have dramatic effects on ecological health and agricultural irrigation.”

By including declining water table levels in the analysis, the study found that streamflow reductions nearly double when compared to simulations that examined the impacts of climate change in the region without accounting for groundwater declines. This is because of the multiple impacts occurring simultaneously: less water flows to streams from the aquifers, while more stream water drains into the soil.

The research demonstrates the need to jointly manage forest and groundwater in the Upper Colorado River Basin, as well as account for the exchange of surface and groundwater in mountain basins, to minimize streamflow declines under climate change, Carroll says.

“I think of groundwater as your savings account,” she adds. “Snowpack is like your checking account; it changes from year to year. Groundwater is a longer-term investment—it can smooth out the really wet and dry years. But if you start consistently reducing that groundwater year after year, then you can no longer modulate those extremes.”

More information:
Declining Groundwater Storage Expected to Amplify Mountain Streamflow Reductions in a Warmer World, Nature Water (2024). www.nature.com/articles/s44221-024-00239-0

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Climate change will reduce streamflow in the upper Colorado river basin as groundwater levels fall, study finds (2024, May 23)
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Colorado

Cleanup continues in Colorado after train derails into Gunnison River, spills over 8,000 gallons of

Published

10 hours ago

December 21, 2025

Press Room

Cleanup continues in Colorado after train derails into Gunnison River, spills over 8,000 gallons of

Two weeks after a rockslide in Colorado derailed a train into the Gunnison River, spilling thousands of gallons of fuel into the water, the Environmental Protection Agency said the initial cleanup operation is coming to a close. They added that additional oil recovery and a more methodical assessment of impacts to the shoreline are underway.

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Colorado

Windstorm batters Colo., leave tens of thousands without power; restoration expected by Saturday night

Published

22 hours ago

December 20, 2025

Press Room

Windstorm batters Colo., leave tens of thousands without power; restoration expected by Saturday night

BOULDER COUNTY, Colo. — Colorado’s foothills were hit by hurricane-force winds Friday morning, with gusts reaching 112 mph in Boulder County. The storm caused damage, outages, fires, and travel disruptions, but no injuries were reported.

Earlier in the week, on Wednesday afternoon and evening, a previous windstorm brought gusts up to 109 mph, knocking down trees and power lines and sparking fires near Yuma.

No serious injuries were reported from the fires near Yuma. Authorities believe no homes were lost. All fires were contained by Thursday night after burning just over 14,000 acres.

Power outages

Xcel Energy carried out another public safety power shutoff (PSPS) on Friday in response to hurricane-strength winds in the Front Range foothills, as crews worked around the clock to restore power to thousands of customers after initiating a Wednesday PSPS.

Xcel said PSPS conditions subsided as of 5 a.m. Saturday. However, about 57,207 Xcel customers were still without power.

Xcel Energy

The utility company said it’s aiming to restore power to customers by 10 p.m. Saturday, but warned that the outage could extend into Sunday for some customers.

“The safety of crew members is paramount as they work to restore power. Xcel Energy asks customers to help keep crew members safe as they work diligently to restore power as quickly as possible,” wrote Xcel Energy in a release.

Xcel said it has identified 396 customers who have been without power since the initial outage on Wednesday. The company said these customers are being prioritized as restoration efforts continue followed by other high-needs areas.

xcel crews power shutoff_dec 18 2025.jpg — Xcel Energy workers toil to repair power lines on a street closed after hurricane-force winds whipped through the metropolitan area and interrupted service to residents Thursday, Dec. 18, 2025, in Denver. (AP Photo/David Zalubowski)

Xcel set up resource centers and charging stations in Evergreen, Gilpin County, Lakewood, and Idaho Springs.

On Saturday, Gov. Jared Polis urged residents to avoid directing their frustration at Xcel’s frontline crews over ongoing outages, saying workers are working long hours to restore service.

“As many Coloradans await the return of power to their homes and communities, I want to urge everyone not to take their frustrations with power being out on the hardworking men and women who make up the Xcel crews. The company and its crews are working around the clock to ensure our safety and to restore power. While I have expressed great frustration with Xcel and there’s much room for improvement in communications about what’s going on and timelines, I am grateful for Xcel’s frontline workers and all those people working to restore people’s power. Please thank them if you see them,” Polis said in a statement.

CORE Electric Cooperative, which provides power to parts of Clear Creek, Jefferson, and Park counties, said that 9,281 customers lost power during Friday’s storm.

CORE said the return of service for most members will likely not occur until later in the day on Saturday, as more favorable weather will help with restoration efforts. However, strong winds are still expected, and many trees have been weakened during the storm.

Damage and closures

Reports of downed trees, power lines, and street poles in and around Boulder and across the foothills during Friday’s wind event flooded emergency dispatch.

In Longmont, Friday’s windstorm severely damaged the roof of Longmont Climbing Collective, 155 Pinnacle Street, prompting the closure of the business as crews work to replace the roof.

Longmont Climbing Collective said in a Facebook post that it hopes to reopen Sunday or Monday, but it may take longer. No injuries were reported.

Downed trees and street poles blocked roads and trails across Boulder County, causing major closures, including portions of CO 72, CO 93, US 36, and CO 128. But some reopened by nightfall.

In the Allenspark area of Boulder County, a propane tanker on CO 7 rolled over after hitting black ice on Friday, trapping the occupants and prompting an evacuation and the closure of the highway.

According to the Allenspark Fire Protection District, high winds and leaking diesel fuel at the crash scene made the situation particularly sensitive and extended the time needed to resolve it.

Due to concerns about possible propane leakage, residents and businesses were evacuated. However, no propane leakage was ultimately found.

No major injuries were reported.

Friday’s storm also closed schools across Boulder and Jefferson counties, as well as Evergreen.

Here are the top 10 wind speeds recorded on Friday from the National Weather Service:

112 MPH — 3 NW Marshall, Boulder, CO
110 MPH — Sunshine, Boulder, CO
102 MPH — 2 WNW Niwot, Boulder, CO
99 MPH — 1 NE Crisman, Boulder, CO
97 MPH — 1 S Wallstreet, Boulder, CO
96 MPH — 2 SW Hygiene, Boulder, CO
95 MPH — 1 NE Crisman, Boulder, CO
95 MPH — 3 S Carter Lake, Larimer, CO
94 MPH — 3 N Berthoud Pass, Grand, CO
92 MPH — 5 N Boulder, Boulder, CO

DIA impacts

Friday’s strong winds created a rough start to the December holiday travel season at Denver International Airport.

FlightAware reported more than 1,200 delays at DIA on Friday—the most nationwide—along with more than 80 cancellations.

A plane takes off at Denver International Airport.

On Saturday, the numbers dropped considerably, resulting in only 88 reported delays.

Several pilots reported moderate-to-severe or even severe turbulence on Friday.

The Federal Aviation Administration defines turbulence as “severe” when it “causes large, abrupt changes in altitude and/or attitude. It usually causes large variations in indicated airspeed. Aircraft may be momentarily out of control.”

Back‑to‑back windstorms batter Colorado, leave tens of thousands without power

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Colorado

Avs’ home heater continues as Colorado beats Winnipeg 3-2 in chippy win

Published

1 day ago

December 20, 2025

Press Room

Avs’ home heater continues as Colorado beats Winnipeg 3-2 in chippy win

The Avs on home ice remain as close to invincible as a sports team can get.

Colorado beat Winnipeg 3-2 on Friday at Ball Arena, improving to 14-0-2 in Denver. The win extended the longest home point streak to start a season in franchise history, and the Avs’ 12th straight victory at home is the longest in the NHL this season and second-longest streak in franchise history.

“When other teams play here, it’s tough to come into this building,” defenseman Josh Manson said. “When the fans get behind us, momentum shifts. We score a goal, they get loud, the building gets rocking and the momentum starts to carry and we can feel it. And from there, we can start pouring it on.”

The Avs didn’t play perfect on Friday, giving up a shorthanded goal and battling through several Winnipeg surges after reigning Hart Trophy and Vezina Trophy winner Connor Hellebuyck settled into the game.

But as they have all season, Colorado found a way to win in front of the Avs faithful in a game featuring four scuffles, highlighted by a fist fight between Manson and the Jets’ Tanner Pearson. The Avs’ only home losses this year came in a pair of 5-4 shootout setbacks, to Dallas on Oct. 11 and Carolina on Oct. 23.

Since then, Colorado’s been a sure bet to prevail at “The Can.”

“This was one of our better defensive efforts of the year — physical, and we spent some time in the D-zone in the second period and didn’t give up any dangerous chances five-on-five really,” Avs head coach Jared Bednar said. “Made a mistake on the power play, made a mistake on the penalty kill, but besides that I liked our game tonight.”

The Avs started fast against struggling Winnipeg, which has battled injuries and inconsistencies while looking like a shadow of the team that won last season’s Presidents’ Trophy. Colorado blitzed Hellebuyck with a number of quality shots in the first 10 minutes, then finally broke through with Brent Burns’ goal.

“Right from the drop of the puck, we were taking it to them,” Manson said. “… (During this stretch of home dominance) we’ve set the pace on teams.”

Burns, the oldest active NHL player, wristed one home from behind the right playoff circle as his shot deflected off the skate of a Winnipeg defender to make it 1-0.

Five minutes later, Colorado made it 2-0 thanks to a highlight-reel combination between Nathan MacKinnon and Martin Necas. MacKinnon, tied with Edmonton’s Connor McDavid for the NHL points lead entering the night with 58, made a precise pass that split two defenders and found Necas streaking down the center of the ice. Necas beat Hellebuyck on the bottom right shelf.

“When we beat them up ice, we’re capable (of finishes like that),” Necas said.

But in the second period, Hellebuyck tightened up, turning away several scoring chances as the Jets killed three Avs power plays and the crowd buzzed off of Manson’s fight with Pearson.

After both players went to the penalty box just under three minutes into the period, the jumbotron cam jumped from Manson to Pearson, with the former getting met with deafening cheers and the latter with a chorus of boos.

“(That) gets you fired up a little bit,” Parker Kelly said.

But on Colorado’s third man-advantage of the period, the Jets stole the momentum back with a short-handed goal.

Off a Hellebuyck save, Alex Iafallo possessed the puck and cleared up ice high off the glass. Morgan Barron outskated Cale Makar down the ice to retrieve the bouncer, then beat Scott Wedgewood one-on-one with a backhanded shot to quiet the crowd and make it 2-1 with 37 seconds left in the frame.

“We weren’t worried after that,” Manson said. “If anything, I was thinking in my mind, ‘We’re going to go get one here at the start of the third period.’”

The Avs did just that.

Less than two minutes into the third, Colorado grabbed the mojo right back. Manson blasted a shot from up near the blue line, which deflected off a screening Kelly and past Hellebuyck for a 3-1 lead.

“I saw it go to low to high and I just tried to beat my guy to the net,” Kelly said. “(Manson) was walking down mainstream. Honestly, I was just there to try and provide a screen. I thought (Manson) was going to rip it. I don’t know if it got tipped, but the shot was along the ice and my stick was on the ice. Just tried to get a little touch on it.”

But the Jets quickly answered about 90 seconds later, capitalizing on a hooking penalty on Devon Toews as Mark Scheifele scored just seven seconds into Winnipeg’s power play to again make it a one-goal game.

Midway through the period, the Avs had a goal wiped off the board. Kelly deflected the puck into the net off a shot by Samuel Girard, but Kelly used high-sticking to do it, negating the score.

From there, Wedgewood and the Colorado defense held on as the Avs notched their 56th and 57th points of the season. Wedgewood made 20 total saves, including two saves in the final minute to seal the win for Colorado (25-2-7).

“We got heavy around the net, and Wedgie played great between the pipes,” Manson said. “We were making good decisions with the puck at the end of the game… We made smart plays and didn’t force anything in the last eight, 10 minutes of that game.”

The longest home win streak in Avs history came during their championship season in 2021-22, when Colorado won 18 straight in Denver from Nov. 11 to Jan. 30.

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