SRP Flowtography, Snowtography On Display

Time-Lapse Technology Helps Visualize, Monitor Stream/Snow, Watershed Conditions and Changes

Five years after its unveiling in Arizona, SRP Flowtography technology is about to be taken to the next level.

Although it started with a catchy name, SRP Flowtography has more than held its own as a simple and inexpensive way to monitor stream flow by using time-lapse cameras and an in-stream visual staff gage (event gage) to provide a better understanding of stream behavior and overall watershed conditions.

With the success of SRP Flowtography came the development of its sister technology, SRP Snowtography, which also utilizes time-lapse imagery to record not only snow levels during the winter but provides four-season monitoring of watershed health over time at strategically selected elevations in between 4,000 to 8,000 feet.

Phoenix-based Salt River Project (SRP) has been utilizing SRP Flowtography since its launch in 2013 and added SRP Snowtography in 2017, learning more each day about the additional benefits this technology offers. Both devices have taken watershed monitoring and management to a whole new level, beyond conventional devices that track runoff from snowmelt and rainfall -- while also offering visual proof of snow accumulation or a stream’s flow or lack thereof.

Lee Ester, manager of SRP’s Water Measurement department and an SRP employee for more than 30 years, is taking SRP Flowtography and SRP Snowtography on the road for the first time this week at the American Water Works Association’s ACE18 Annual Conference & Exposition in Las Vegas.

Ester’s group is tasked with, among other things, the important job of measuring river and stream flows across SRP’s 13,000-square-foot watershed before the rain and melting snow is captured and stored in the reservoirs along the Salt and Verde rivers in Arizona. Those drops eventually wind up behind the seven dams operated and managed by SRP, the largest provider of water and power to the greater Phoenix metropolitan area.

Ester has spent much of his career at SRP searching for new ways and technologies that make it more efficient, more informative and less costly for water managers to track conventional water flow data. But even with the variety of rain gages and other measuring equipment at his disposal, Ester had never come across a device to track the runoff from snowmelt and rainfall that also offered visual proof of snow accumulation or a stream’s flow -- until now.

Taking it into his own hands, in the spring of 2012 Ester developed the SRP Flowtography technology, which is a method using time-lapse imagery and a precisely located in-stream event gage to record all stream-flow activity and conditions at a particular location. These images can then be combined with electronic data for precise water-depth calibration and event analytics.

When the electronic data is collected, so too are the images from the SRP Flowtography equipment on site. Back in the office, the conventional electronic data is processed for stage accuracy by consulting, comparing and verifying the images collected against the images collected, which is especially useful in seasonal and flashy ephemeral stream events.

“Conventional water depth data collection methods require expensive equipment and infrastructure to be installed and maintained,” said Ester. “When finished the site is left to operate on its own with an expectation for accurate data, but accuracy is not always assured and only spot visits are possible to ‘calibrate’ -- or make adjustments -- to the data collected once back in the office.

“With SRP Flowtography and SRP Snowtography we are collecting 35,000 photos per site per year, and those final images provide a highly needed source of ‘secondary’ information to ensure that stream events are correctly characterized.”

Ester noted that this technology has already been field tested for five years by his department across the Verde Watershed and at other client sites to track watershed conditions and health in Arizona’s forests.

“In the science of hydrology and in watershed management, monitoring and measurement, a picture is now worth more than words with SRP Flowtography and SRP Snowtography,” he said.