ARIZONA NEWS

Explosive population growth will bring challenges to metro Phoenix’s water future

Apr 25, 2022, 4:45 AM | Updated: Apr 28, 2022, 9:33 am

Editor’s Note: This is the first of a five-part series called “KTAR Water Watch,” which will explore the present and future of the water supply across Arizona and metro Phoenix.

PHOENIX — The images are shocking. Areas submerged for decades are now islands.

Lake Mead and Lake Powell, two reservoirs Arizona relies on for its water, are historically low, with each about a third full.

Arizona State University climatologist Randy Cerveny says in addition to climate change, it’s explosive population growth in Arizona and other states that rely on water from the Colorado River via Lake Mead and Lake Powell that will present challenges in the future in the Valley.

Cerveny says most of the water that fills the Colorado River is due to melting snowpack in Colorado. The state is going through a historically dry period and the Rockies haven’t experienced consistent, above-normal precipitation.

“The river is so severely allocated that just south of Yuma, every remaining drop is sent to California,” Cerveny said. “It doesn’t reach the Gulf of California anymore. Even if there were to be more extra water that fell on the Colorado Rockies and into the Colorado River, it has already been allocated.

“We will never see those lakes ever go back to the days prior to the drought that we’re in right now.”

The Valley gets about 30% of its water from the Colorado River via the Central Arizona Project canal.

Salt River Project provides about half of the water for the Phoenix metropolitan area — approximately 2.5 million customers — from its chain of reservoirs on the Salt River and Verde River. The rest of the Valley water supply comes from groundwater.

The region’s ongoing population and business growth could strain the overall system, but Cerveny says the water sources won’t all dry up at the same time.

But is the business growth sustainable given the available sources?

“It will depend on which community they’re going to be affiliated with because different organizations will have to use different sources of water,” Cerveny said. “SRP is pretty picky about who they allow to have access to their water. There are other sources that charge a lot for their particular water.”

Storage in SRP’s reservoirs has dropped very little since 1996 thanks in part to some recent wet winters in 2017, 2019 and 2020.

The winters of 2005 and 2010 were also solid, while last summer’s powerful monsoon also added water to the system.

SRP’s chain of six reservoirs on the Salt River and Verde River provide about half of the Valley water supply and collectively are at about 70% capacity.

Central Arizona Project saw the first and so far only water cuts because of the declining reservoir levels, but the reduction only impacts agriculture at this time.

Bo Svoma, staff scientist and meteorologist with SRP, says the Colorado River basin stream flows into Lake Powell are very sensitive to warming, whereas the Salt and Verde rivers are about five times less sensitive to warming.

“What warming does is it increases the evaporative losses from the landscape and results in less water for stream flow,” Svoma said. “The Colorado River is more sensitive to that than the Salt and Verde.

“That one reason is why things aren’t as dire on the Salt and Verde.”

Even with the Valley’s explosive population growth since the mid 1990s, Svoma says demand has actually gone down.

“SRP has been delivering less water because of better efficiencies and water use and people being more conservation minded with their water use, which is really important,” Svoma said.

“That brings SRP into a perfect balance with the long term median inflow into the system is equal to our water deliveries, which is not the case on the Colorado River, which is over-allocated.”

Svoma doesn’t see Lakes Mead and Powell dropping to the point that they can no longer supply water to the Valley.

“I think it will be challenging to address the over allocation on the Colorado River, but people are working on that,” Svoma said.

“What happens with future precipitation is very uncertain, but from a western U.S. perspective the climate model projections are leaning toward increased winter precipitation for the Colorado River is a positive.”

Will the water situation impact the ability to lure business, specifically semiconductor outfits? Svoma says yes.

“Certainty in the water supply is attractive to businesses and there are several current projects that could increase the resiliency and sustainability of Arizona’s water supply,” Svoma said.

We want to hear from you.

Have a story idea or tip? Pass it along to the KTAR News team here.

Arizona News

The eastbound Loop 202 South Mountain freeway was closed in Phoenix on Feb. 26, 2024, for a fatal c...

KTAR.com

Eastbound Loop 202 South Mountain Freeway closed in Phoenix for fatal crash

The eastbound Loop 202 South Mountain freeway was closed in Phoenix on Monday for a fatal crash, authorities said.

20 minutes ago

Mugshot of Jill Houchens, who was arrested Feb. 19, 2024, on 146 counts of animal abuse and neglect...

KTAR.com

Arizona woman arrested on nearly 150 animal abuse and neglect charges

An Arizona woman faces nearly 150 charges after more than 20 animals, including five that were dead, were removed from her property earlier this month, authorities said.

2 hours ago

Sun at high noon over a prison....

SuElen Rivera

Man sentenced to over 5 years for coordinating drug smuggling into Arizona

A man was sentenced last week to over five years in prison for his role in coordinating drug smuggling into Arizona, authorities said.

3 hours ago

Blurry photo of an ambulance with lights on at night...

KTAR.com

1 teenager killed, another seriously injured in rollover collision in Phoenix

One teenager was killed and another was seriously injured in a rollover collision in northwest Phoenix early Sunday, authorities said.

5 hours ago

Mesa man smiles for picture!...

KTAR.com

Silver Alert issued for Mesa man with cognitive disability

A silver alert was issued Sunday night for a Mesa man with a cognitive disability last seen in Mesa, authorities said.

6 hours ago

The Grand Canyon Railway returns on March 2. (Grand Canyon Railway)...

David Veenstra

Grand Canyon Railway to run train pulled by steam engine on select dates this year

The Grand Canyon Railway resumes operations this weekend, offering departures every first Saturday of the month through October.

7 hours ago

Sponsored Articles

...

DISC Desert Institute for Spine Care

Sciatica pain is treatable but surgery may be required

Sciatica pain is one of the most common ailments a person can face, and if not taken seriously, it could become one of the most harmful.

...

Day & Night Air Conditioning, Heating and Plumbing

Day & Night is looking for the oldest AC in the Valley

Does your air conditioner make weird noises or a burning smell when it starts? If so, you may be due for an AC unit replacement.

...

Sanderson Ford

The best ways to honor our heroes on Veterans Day and give back to the community

Veterans Day is fast approaching and there's no better way to support our veterans than to donate to the Military Assistance Mission.

Explosive population growth will bring challenges to metro Phoenix’s water future