Notice the dry canal in Mesa and the East Valley? This is why it was empty for 6 weeks

Ryan Randazzo | The Republic | azcentral.com

If you've noticed that the usually flowing Central Arizona Project canal was dry the past six weeks, that should change starting Tuesday as the canal refills.

Colorado River water will flow to Tucson, Mesa, Chandler and Gilbert after $6 million in repairs to the canal where it tunnels beneath the Salt River, near Power Road and the Loop 202 in north Mesa.

Water was still delivered to customers, including Phoenix, west of that point, but about 75% of CAP water is normally delivered beyond there, officials said Monday.

Several cities, tribes and irrigation districts rely on CAP water deliveries to supplement water supplies they get from the Salt and Verde rivers and from groundwater pumping.

CAP general manager Ted Cook said plans for the repairs took about three years so that all of the customers who would have to go without Colorado River water for the duration could prepare.

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The repairs were needed to the 1.6-mile-long tunnel, or siphon, where the CAP water uses a 21-foot diameter steel tunnel deep below the Salt River. The inside of the pipe needed recoating to protect against rust, officials said. The last such repairs were made almost a decade ago.

It is one of 10 siphons on the CAP that carries water under natural waterways, including the Agua Fria, New, Gila and Santa Cruz rivers.

"One of our most important functions at CAP is to make sure the system we know as the Central Arizona Project is maintained in a way that it continues to deliver a reliable source of water as efficiently as possible," CAP board president Lisa Atkins said.

Pumps lift water 2,900 feet

Once CAP water emerges from the siphon under the Salt River, it arrives at a pumping station where it is lifted 75 feet uphill, and the canal heads south toward Pinal County and beyond.

The CAP lifts water about 2,900 feet on its 336-mile journey from the Colorado River to its endpoint south of Tucson with 14 pumping stations.

The CAP is the largest single user of electricity in the state, and until recently, got much of the power to run those pumps from the Navajo Generating Station coal plant near Page.

With that plant's closure last month, CAP has relied on a variety of natural-gas plant contracts and market purchases, Cooke said.

The first contract for solar power to run the CAP will deliver energy by Jan. 1, said Darrin Francom, a director of operations for CAP.

CAP also has signed a second contract from another yet-to-be-built solar plant with large batteries to provide the canal power, he said.

Reach reporter Ryan Randazzo at ryan.randazzo@arizonarepublic.com or 602-444-4331. Follow him on Twitter: @UtilityReporter.

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