At Salt River Project (SRP), we’ve always believed that every drop of water saved here in the Valley is a drop we can store in our reservoirs to use another day. Keeping track of all of those drops is one of the more important jobs we have at SRP, where we’re working every day to ensure there’s enough water for today and tomorrow.

While Valley residents are stepping up their efforts to conserve water at home, perhaps while participating in our “Together We Conserve” campaign at, SRP is busy managing the Valley’s water supply to meet the water needs of our growing communities.

Constantly monitoring our most precious resource is something SRP has been doing for more than 100 years, and today it’s our job to carefully estimate how much water is available to the Valley each and every day.

That’s where SRP’s Water Measurement group comes in. We use unique, state-of-the-art electronic instrumentation and tried-and-true field practices to measure precipitation first collected in the form of rain and snow in the most remote areas of the 13,000-square-mile watershed served by the Salt and Verde rivers, then the raw water delivered in the Valley through 1,265 miles of canals, laterals and ditches.

And when billions of gallons of water every year pass through flow-metering devices owned by SRP and Valley cities, measurement is very important. In many instances, SRP is relied upon by others as a resource/service provider for water-measurement audits, field verifications and project management.

To make sure SRP gets it right, we also operate a flow-meter repair and calibration facility that is the only one of its kind in Arizona and one of the reasons SRP is recognized as a regional leader in the development of adaptable water-measurement instrumentation. Our shop’s precision calibration and measurement methods adhere to the National Institute of Standards and Testing, and our technicians have been certified by one of the largest international manufacturers of flow meters.

Flow metering is an important part of SRP’s water operations because it provides key information about the amount of water we deliver to SRP shareholders and into the Valley’s municipal water-delivery systems, which today receive nearly half of the 325 billion gallons of water we deliver each year to municipal, industrial, agricultural and urban irrigation systems. That ability to measure water consistently also has economic and environmental implications for architects, engineers, homeowners associations, irrigation districts, reclamation projects and many others.

A couple of examples of where we measure water flow at opposite ends of the Valley can be found in the two underground water-recharge facilities that SRP utilizes, the Granite Reef Underground Storage Project (GRUSP), located just north of the Salt River near Mesa, and at NAUSP (New River-Agua Fria Underground Storage Project) in Glendale, just east of the New River.

Those two storage projects help ensure a reliable and adequate supply of water for our growing Valley and our municipal partners in the two projects, Phoenix, Chandler, Gilbert, Mesa, Scottsdale and Tempe with GRUSP, and Avondale, Chandler, Glendale and Peoria with NAUSP. They provide a low-cost alternative to other storage options such as reservoirs, while also enabling Arizona to maximize the use of its Colorado River entitlement by storing water underground.

Since GRUSP was completed in 1994 and NAUSP in 2006, the amount of water that has passed through our flow-metering equipment at those two facilities combined is more than the capacity of huge Theodore Roosevelt Lake, which holds about 70 percent of the surface water stored by SRP.

Those are a lot of drops that get put back into the ground to bank for future use during drought times. But, much like we have been doing for more than a century, we’ll be doing our best to track every drop.


• Lee Ester is manager of Salt River Project’s Water Measurement group.

(0) comments

Welcome to the discussion.

Keep it Clean. Please avoid obscene, vulgar, lewd, racist or sexually-oriented language.
Don't Threaten. Threats of harming another person will not be tolerated.
Be Truthful. Don't knowingly lie about anyone or anything.
Be Nice. No racism, sexism or any sort of -ism that is degrading to another person.
Be Proactive. Use the 'Report' link on each comment to let us know of abusive posts.
Share with Us. We'd love to hear eyewitness accounts, the history behind an article.