The ever-flowing water through the Central Arizona Project canal will soon go underground, in a sense, for some Valley communities with the help of the Old Pueblo.

“The City of Tucson is just making their facilities available to these Valley cities to help them be more resilient,” said John Kmiec with Tucson Water.

In early August, Tucson made water storage agreements with the City of Scottsdale, the Town of Gilbert, and the City of Peoria, allowing them to store CAP water in their underground storage facilities.

When there’s excess water for Valley cities, they can bank it with the City of Tucson.

During an ongoing drought, Tucson can deliver the banked water to those municipalities as part of an exchange.

Brian Biesemeyer, the executive director of Scottsdale Water, says the water storage agreement acts like a rainy-day fund.

“It is a savings account that we can use in the future that allows us to mitigate cuts on the Colorado River,” he said.

The agreement states that the City of Scottsdale can store up to 3,000 acre-feet of CAP water per year in Tucson for 10 years, while the Town of Gilbert can store 300 acre-feet per year, and the City of Peoria can store 10,000 acre-feet per year.

For context, one acre-foot of water is enough to supply about three Arizona homes for an entire year.

Tucson and Phoenix have been doing this type of water agreement since 2017. The City of Phoenix has stored nearly 200,000 acre-feet of water in Tucson’s storage facilities since then.

With the concerning outlook of the Colorado River, communities are being proactive, so they’ll have enough water saved amid an uncertain future.

“Being able to take CAP water when it is in excess and bank it in an aquifer in the state of Arizona makes the utility more resilient over time,” Kmiec said.

So far, the City of Scottsdale has signed off on the agreement. According to the City of Tucson, Gilbert and Peoria are working on it.