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

(SRP Photo) (SRP Photo) (SRP Photo) (SRP Photo) (SRP Photo)

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

patrol car in front of caution tape...

Police investigating 2 south Phoenix homicides from over the weekend

Investigations are underway after two people were found fatally shot Sunday morning in separate south Phoenix shootings, authorities said. 

1 hour ago

Arizona man sentenced after attempted child sex trafficking...

Arizona man gets 7 years in prison for attempted child sex trafficking

An Arizona man was sentenced to seven years in prison for attempted child sex trafficking on Thursday, officials said.

2 hours ago

The Boys and Girls Club city facility at 300 E. Chandler Blvd is set to be renovated thanks to an a...

Serena O'Sullivan

East Valley city approves $1.3 million renovation of Boys and Girls Club facility

The city of Chandler said it approved an amended lease agreement to renovate the Chandler Compadres facility for $1.3 million last week.

2 hours ago

(Phoenix Police Department Photo/via YouTube)...

Police share body cam footage related to fatal shooting of alleged carjacker in Glendale

The Phoenix Police Department released body camera footage related to an early September shooting of an alleged carjacker on Friday.

3 hours ago

A new family entertainment facility is expected to open at a retail center in Peoria. (Avison Young...

Phoenix Business Journal Staff

Indoor family fun park concept set for Arizona debut in West Valley

Slick City Action Park, an indoor entertainment center, has signed a lease for 35,000 square feet in Peoria, its first Arizona location.

3 hours ago

Birdcall storefront...

Brandon Gray

Chicken restaurant Birdcall expands with grand opening in Phoenix

Denver-based chicken restaurant Birdcall announced the grand opening of its second Arizona location in the Valley.

11 hours ago

Sponsored Articles

Home moving relocation in Arizona 2023...

BMS Moving

Tips for making your move in Arizona easier

If you're moving to a new home in Arizona, use this to-do list to alleviate some stress and ensure a smoother transition to your new home.


Ignite Digital

How to unlock the power of digital marketing for Phoenix businesses

All businesses around the Valley hopes to maximize their ROI with current customers and secure a greater market share in the digital sphere.



Thank you to Al McCoy for 51 years as voice of the Phoenix Suns

Sanderson Ford wants to share its thanks to Al McCoy for the impact he made in the Valley for more than a half-decade.

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