EXPLAINER: Western states face first federal water cuts

U.S. officials are expected to declare the first-ever water shortage from a river that serves 40 million people in the West

Drought Explainer Water Shortage
Drought Explainer Water Shortage

U.S. officials on Monday are expected to declare the first-ever water shortage from a river that serves 40 million people in the West, triggering cuts to some Arizona farmers next year amid a gripping drought.

Water levels at the largest reservoir on the Colorado River — Lake Mead — have fallen to record lows. Along its perimeter, a white “bathtub ring” of minerals outlines where the high water line once stood, underscoring the acute water challenges for a region facing a growing population and a drought that is being worsened by hotter, drier weather brought on by climate change.

States, cities, farmers and others have diversified their water sources over the years, helping soften the blow of the upcoming cuts. But if current conditions persist — or intensify — additional cuts in coming years will be more deeply felt.

Lake Mead was formed by building Hoover Dam in the 1930s. It is one of several man-made reservoirs that store water from the Colorado River, which supplies drinking water, irrigation for farms and hydropower to Arizona, California Colorado, Nevada New Mexico, Utah, Wyoming and parts of Mexico.

But water levels at Lake Mead and Lake Powell the river's two largest reservoirs, have been falling for years and faster than experts predicted. Scorching temperatures and less melting snow in the spring have reduced the amount of water flowing from the Rocky Mountains, where the river originates before it snakes 1,450 miles (2,334 kilometers) southwest and into the Gulf of California.

“We’re at a moment where we’re reckoning with how we continue to flourish with less water, and it’s very painful,” said Sarah Porter, director of the Kyl Center for Water Policy at Arizona State University.

HOW IS THE RIVER WATER SHARED?

Water stored in Lake Mead and Lake Powell is divvied up through legal agreements among the seven Colorado River basin states, the federal government, Mexico and others. The agreements determine how much water each gets, when cuts are triggered and the order in which the parties have to sacrifice some of their supply.

Under a 2019 drought contingency plan, Arizona, Nevada, California and Mexico agreed to give up shares of their water to maintain water levels at Lake Mead. The voluntary measures weren't enough to prevent the shortage declaration.

WHO DOES LAKE MEAD SERVE?

Lake Mead supplies water to millions of people in Arizona, California, Nevada and Mexico.

Cuts for 2022 are triggered when predicted water levels fall below a certain threshold — 1,075 feet (328 meters) above sea level, or 40% capacity. Earlier this summer, Lake Mead's elevation hit its lowest point since being filled in the 1930s at 1,068 feet (326 meters).

Further rounds of cuts are triggered when projected levels sink to 1,050, 1,045 and 1,025 feet (320, 318 and 312 meters).

Eventually, some city and industrial water users could be affected.

Lake Powell's levels also are falling, threatening the roughly 5 billion kilowatt hours of electricity generated each year at the Glen Canyon Dam.

Colorado, New Mexico, Utah and Wyoming get water from tributaries and other reservoirs that feed into Lake Powell. Water from three reservoirs in those states has been drained to maintain water levels at Lake Powell and protect the electric grid powered by the Glen Canyon Dam.

WHICH STATES WILL BE AFFECTED BY THE CUTS?

In the U.S., Arizona will be hardest hit and lose 18% of its share from the river, or 512,000 acre-feet of water. That's around 8% of the state's total water use.

An acre-foot is enough water to supply one to two households a year.

Nevada will lose about 7% of its allocation, or 21,000 acre-feet of water. But it will not feel the shortage because of conservation efforts and alternative sources of water.

California is spared from immediate cuts because it has more senior water rights than Arizona and Nevada.

Mexico will see a reduction of roughly 5%, or 80,000 acre-feet.

WHO IN THOSE STATES WILL SEE THEIR WATER SUPPLY CUT?

Farmers in central Arizona, who are among the state’s largest producers of livestock, dairy, alfalfa, wheat and barley, will bear the brunt of the cuts. Their allocation comes from water deemed “extra” by the agency that supplies water to much of the region, making them the first to lose it during a shortage.

As a result, the farmers will likely need to fallow land — as many already have in recent years because of persisting drought — and rely even more on groundwater, switch to water-efficient crops and find other ways to use less water.

Water suppliers have planned for the shortage declaration by diversifying and conserving their water supply, such as by storing water in underground basins. Still, water cuts make it harder to plan for the future.

The Central Arizona Project, which supplies water to Arizona’s major cities, will no longer bank river water or replenish some groundwater systems next year because of the cuts.

“It’s a historic moment where drought and climate change are at our door,” said Chuck Cullom of the Central Arizona Project.

Cities like Las Vegas, Phoenix and Tucson, and Native American tribes are shielded from the first round of cuts.

CAN THE DECLINE OF LAKE MEAD BE REVERSED?

Water levels at the reservoir have been falling since 1999 due to the dry spell enveloping the West and increased water demand. With weather patterns expected to worsen, experts say the reservoir may never be full again.

Though Lake Mead and Lake Powell could theoretically be refilled, planning for a hotter, drier future with less river water would be more prudent, said Porter of Arizona State University.

___

Associated Press reporter Felicia Fonseca contributed from Flagstaff, Arizona.

___

The Associated Press receives support from the Walton Family Foundation for coverage of water and environmental policy. The AP is solely responsible for all content. For all of AP’s environmental coverage, visit https://apnews.com/hub/environment and drought coverage, visit https://apnews.com/hub/droughts.

Register for free to continue reading

Registration is a free and easy way to support our truly independent journalism

By registering, you will also enjoy limited access to Premium articles, exclusive newsletters, commenting, and virtual events with our leading journalists

Please enter a valid email
Please enter a valid email
Must be at least 6 characters, include an upper and lower case character and a number
Must be at least 6 characters, include an upper and lower case character and a number
Must be at least 6 characters, include an upper and lower case character and a number
Please enter your first name
Special characters aren’t allowed
Please enter a name between 1 and 40 characters
Please enter your last name
Special characters aren’t allowed
Please enter a name between 1 and 40 characters
You must be over 18 years old to register
You must be over 18 years old to register
Opt-out-policy
You can opt-out at any time by signing in to your account to manage your preferences. Each email has a link to unsubscribe.

By clicking ‘Create my account’ you confirm that your data has been entered correctly and you have read and agree to our Terms of use, Cookie policy and Privacy notice.

This site is protected by reCAPTCHA and the Google Privacy policy and Terms of service apply.

Already have an account? sign in

By clicking ‘Register’ you confirm that your data has been entered correctly and you have read and agree to our Terms of use, Cookie policy and Privacy notice.

This site is protected by reCAPTCHA and the Google Privacy policy and Terms of service apply.

Register for free to continue reading

Registration is a free and easy way to support our truly independent journalism

By registering, you will also enjoy limited access to Premium articles, exclusive newsletters, commenting, and virtual events with our leading journalists

Already have an account? sign in

By clicking ‘Register’ you confirm that your data has been entered correctly and you have read and agree to our Terms of use, Cookie policy and Privacy notice.

This site is protected by reCAPTCHA and the Google Privacy policy and Terms of service apply.

Thank you for registering

Please refresh the page or navigate to another page on the site to be automatically logged inPlease refresh your browser to be logged in