‘Uncharted territory’: Second-largest reservoir in US plunges to a record low

By Laura Paddison, CNN

(CNN) — Lake Powell, the second-largest reservoir in the United States, provides water and electricity to millions in the West. It has now has shrunk to its lowest level on record, in the latest sign of the alarming crisis unfolding on the drought-stricken Colorado River.

🌧️ Get your local forecast in the CNN Weather app

The reservoir’s levels dropped to 3519.91 feet on Saturday, breaking the record low of 3,519.92 feet set in April 2023, according to data from the US Bureau of Reclamation published Sunday. It is now just under 30 feet away from the point at which its dam will no longer be able to generate hydropower.

The record comes nine days after downstream Lake Mead, the US’s biggest reservoir, dropped to its lowest level since it was first filled nine decades ago. “We are in uncharted territory,” said Jack Schmidt, director of the Center for Colorado River Studies at Utah State University.

Lakes Mead and Powell, which are essentially one gigantic reservoir separated by the Grand Canyon, hold just under 60% of the total water currently stored in the Colorado River basin. The unprecedented decline of these vast bodies of water, which have been shrinking for more than 20 years, drives home the perilous state of the river that feeds them.

Known as the lifeblood of the Southwest, the Colorado River starts in the Rocky Mountains, fed by melting snowpack, and ends in the Gulf of California in Mexico. It provides water to roughly 40 million people and irrigates more than 5 million acres of farmland across seven states: California, Arizona, Nevada, New Mexico, Wyoming, Colorado and Utah.

Climate change-fueled drought and increases in temperature, combined with years of heavy water use, have caused the crucial waterway to shrink by roughly 20% since 2000. And Mead and Powell have been heavily affected.

Spanning parts of Arizona and Utah, Lake Powell formed behind the Glen Canyon Dam, which was constructed in the 1950s. The vast reservoir started filling in 1963 and took 17 years to reach its full pool level of 3,700 feet above sea level.

It’s often referred to as a water “bank account” that can be used in dry years to send supplies downstream to cities, farms and businesses.

The reservoir’s level has always fluctuated. Every year, between May and July, it’s boosted by runoff from melting snow. It then decreases over the rest of the year, leaving distinctive “bathtub ring” formations along its rocky shoreline.

However, this year, as with many recent years, Powell has suffered from a dearth of snow — last winter was one of the driest and warmest on record for the western US.

A major concern is the impact on energy generation. The force of the Colorado River turns the Glen Canyon Dam’s eight huge turbines, producing enough electricity each year to power nearly 500,000 households. It’s relied on by Colorado, Utah, Wyoming, New Mexico, Arizona, Nevada and Nebraska.

The reservoir could now be barreling toward “minimum power pool” — at 3,490 feet — when water levels will be too low to spin the turbines and generate electricity.

This “scary threshold” will be reached this year unless “extraordinary measures” are taken, said Brad Udall, a senior water and climate research scientist at Colorado State University. These include reductions in water releases from Lake Powell and upstream, he added.

The most alarming scenario would see Lake Powell reaching “deadpool” levels of below 3,370 feet. At this point water would no longer be able to flow downstream from the dam at all.

It’s very hard to imagine this, Utah State’s Schmidt said. “I would expect draconian steps to decrease water use to prevent this from occurring. But who knows?”

A spokesperson for the Bureau of Reclamation said it and the Department of the Interior remained “committed to reducing the collective risk of both Lake Powell and Lake Mead falling below critical elevations to protect critical infrastructure to continue to meet the water and hydropower needs of the basin.”

Experts don’t currently believe there is a risk of people’s taps running dry; the Colorado River is a slow-moving crisis and many water managers have taken steps to prepare.

Cities like Pheonix and Tucson “are extremely aware that they are first in line for cuts,” and have taken steps to ensure they have the back-up supplies to meet demand, said Sarah Porter, director of the Kyl Center for Water Policy at Arizona State University. But while cities can pay for alternative water supplies, this might be less feasible for Tribes and smaller communities along the Colorado River, she added.

Powell’s record low comes as the seven states that share the Colorado River’s water wait to find out what cuts will be imposed. After years of fraught negotiations between the states failed to yield a deal, federal authorities have stepped in and are expected to publish a plan in the coming days specifying the exact reductions required of states through 2028.

There is some hope that the El Niño climate pattern, which tends to bring more frequent rain and snow to the Southwest, could help. But experts are clear it will take more than one very wet winter to pull the Colorado River out of crisis.

“Even record snowpack this winter will not be enough to get us out of the danger zone,” Porter said.

The-CNN-Wire
™ & © 2026 Cable News Network, Inc., a Warner Bros. Discovery Company. All rights reserved.