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Blue Mesa Reservoir is half full because of aridification and downstream obligations

The Gunnison River flows into the upper end of a dwindling Blue Mesa Reservoir in September. As of mid-July, the reservoir, which is the biggest in Colorado, was less than half full.
Stephanie Maltarich
/
KBUT
The Gunnison River flows into the upper end of a dwindling Blue Mesa Reservoir in September. As of mid-July, the reservoir, which is the biggest in Colorado, was less than half full.

Blue Mesa Reservoir, downstream of Gunnison, once resembled a deep and healthy lake. But a 22-year drought, coupled with obligations to release water to downstream users, has left the reservoir 69 feet below the normal high watermark.

Experts say it will take a lot more than one snowy winter to refill the reservoir.

The Gunnison River flows for about 25 miles before it becomes Blue Mesa Reservoir, which stores water, creates power, and provides recreation opportunities such as fishing and boating.

Erik Knight, a hydrologist with the Bureau of Reclamation, says the reservoir has seen better days.

“Blue Mesa has reached some of its lowest levels on record last year with those emergency releases last year for the drought-response operation,” said Knight.

Last fall's emergency releases from Blue Mesa dramatically reduced its levels but helped keep Lake Powell’s hydroelectric power plant generating.

This summer, the reservoir sits at aboutone-half of what’s called “full pool,” or full capacity. Officials estimate that it won’t fill more than halfway this year.

Blue Mesa Dam, in May 2019. The 341-foot-tall dams blocks the flow of the Gunnison River and forms Blue Mesa Reservoir.
Brent Gardner-Smith
/
Aspen Public Radio
Blue Mesa Dam, pictured here in May 2019, stands 341 feet high. It blocks the flow of the Gunnison River and forms Blue Mesa Reservoir.

Knight says the reservoir is one piece of The Aspinall Unit. The series of dams are named after Wayne Aspinall, a Colorado congressional representative who worked on Western land and water issues.

“The Aspinall Unit is comprised of three dams and reservoirs,” said Knight. “We've got Blue Mesa Reservoir — that's the largest one and the furthest upstream and stores the most amount of water.”

Just downstream from Blue Mesa are the other two dams: Morrow Point and Crystal.

Although storing water is their main function, the reservoirs in the Aspinall Unit also contribute to the grid that supplies power to about 40 million people.

A view of the downriver side of Blue Mesa Dam. The concrete building at the bottom of the dam houses a hydroelectric plant.
Brent Gardner-Smith
/
Aspen Public Radio
This view shows the downriver side of Blue Mesa Dam. The concrete building at its base houses a hydroelectric plant.

The Blue Mesa Power Plant at the base of the dam started generating electricity in 1967. Eric Langley is the plant supervisor.

Basically these units are run remotely, out of Page, Arizona,” said Langley. “We're just basically here doing the maintenance on and making sure that they're gonna run day to day.”

In the basement of the facility, Langley said how the facility turns water to power.

First, it flows through the dam into the facility through large pressurized pipes called penstocks.

Then, water spins through turbines, creating a magnetic field that puts power onto the grid.

“That's in a nutshell — there's a lot more to that, obviously,” Langley said.

The interior of the Blue Mesa Power Plant, located in a concrete building at the base of Blue Mesa Dam.
Stephanie Maltarich
/
KBUT
The Blue Mesa Power Plant is a concrete building at the base of Blue Mesa Dam.

The water flows through Morrow Point and Crystal before joining the Colorado River near Grand Junction.

Three similar reservoirs in Wyoming, Utah and Arizona create the entire Colorado River Storage Project.

At the opposite end of Blue Mesa, Nicky Gibney, aquatic ecologist for Curecanti National Recreation Area and Black Canyon National Park, explained how Blue Mesa’s landscape has changed over the years.

“We call this over here ‘Sometimes Island’ because right now we’re standing on a peninsula,” said Gibney. “When the water is at full pool, that is actually an island over there — and it seems very far away from being an island right now.”

Nicky Gibney, an aquatic ecologist at the Curecanti National Recreation Area and Black Canyon National Park. The "bathtub ring" visible in the background is an indication of low-water levels in the reservoir.
Stephanie Maltarich
/
KBUT
Nicky Gibney is an aquatic ecologist at the Curecanti National Recreation Area and Black Canyon National Park. The "bathtub ring" visible in the background is an indication of low water levels in the reservoir.

The park manages activities in and around the reservoir, and keeping the waters accessible to visitors is one of the park's top priorities. But Gibney said it’s becoming more difficult with low water levels.

“I think we are struggling with how to do that because everything is just unknown right now, and that’s a new territory for all of us,” said Gibney.

In mid-May, the park announced that the marina would not open for the first time ever.

Blue Mesa Reservoir in May 2019, when it held much more water than it would three years later.
Brent Gardner-Smith
/
Aspen Public Radio
Blue Mesa Reservoir is pictured in May 2019, when it held much more water than it would three years later.

The Colorado River Compact is a federal agreement among seven Western states that defines how water in the Colorado River Basin is divided.

Obligations in the compact to release water downstream is one reason for Blue Mesa’s low levels.

But the biggest culprit is the drought that has lasted two decades.

Eric Kuhn, former director of the Colorado River District and author of “Science Be Dammed,” said when the compact was written in 1922, the river was unusually wet — and today it’s unusually dry.

“And climate change has had a big, big impact on the river,” said Kuhn. “So this equitable division that they came up with 100 years ago didn't consider the impacts of climate change.”

Kuhn says the compact can’t just be rewritten or revised. But it may be reinterpreted to reflect modern water-supply challenges, such as drought and climate change, which are felt at every step along the nearly 1,500-mile river.

This story from KBUT in Crested Butte is part of the station's Headwaters series. It was made possible by The Water Desk, an initiative of the Center for Environmental Journalism at the University of Colorado Boulder. It was shared with Aspen Public Radio via Rocky Mountain Community Radio.
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Stephanie Maltarich is a freelance audio producer and writer based in Gunnison, Colorado. Her work focuses on the environment, social justice and the outdoors. She is currently a science writer and content producer at CIRES at the University of Colorado, Boulder.