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How SRP measures water and the instruments we use

SRP’s water flow measurement instrumentation is both cutting-edge and deeply rooted in Arizona’s history. For more than 100 years, we’ve developed techniques and technology to measure and manage the Valley’s water delivery system.

Calculating the depth and flow of water and snow

Measuring the flow of water is critical to managing the Valley’s water supplies.

That’s why SRP develops and uses state-of-the-art electronic instrumentation to measure moisture in the most remote areas of our watershed, the land that channels rainfall and snowmelt into our river systems.


SRP Flowtography® is a technology designed by SRP researchers to monitor the flow of water in our watershed and make predictions about the water supply.

Flowtography uses solar-powered cameras, situated in Arizona’s high country, to record time-lapse images of strategically placed measurement stakes within stream channels.

Engineers and analysts use these images to calculate water flow. This helps predict how much water will flow through the Salt and Verde river systems into lakes and canals and, eventually, to Valley homes and businesses.

SRP partners with many cities and groups, including the City of Flagstaff, members of the Four Forest Restoration Initiative and Prescott and Prescott Valley, to help them better understand how fires, groundwater pumping and other impacts change the way water flows on the watershed.


SRP Snowtography® helps predict how much water will run off from snowmelt into SRP’s reservoirs.

Snowtography is the technology that is used to record time-lapse images of strategically placed measurement stakes. High-tech cameras are located at elevation levels between 4,000 and 8,000 feet, essentially between Camp Verde and Flagstaff. Much like Flowtography, the camera is attached to a tree or a pole and records time-lapse images of specific areas.

Our team of water-measuring experts uses the images to analyze and record:

  • Snow depth
  • Snowfall length
  • Duration of time on the ground
  • Environmental and climate changes

The information gives us a better understanding of how much water will fill our reservoirs. This is how we can predict the Valley’s future water supply.