SRP, ASU collaboration tackles benefits of forest restoration

SRP and Arizona State University have developed a new approach for estimating the water benefits of forest thinning treatments by creating a model that is being recognized as a method for analyzing forest thinning’s impacts on water.

After a wildfire, rainfall washes ash and debris into rivers and reservoirs, and the large amount of material that washes into SRP’s reservoirs reduces the system’s water storage capacity, potentially damaging water infrastructure downstream such as dams and water treatment plants, a press release explained.

SRP and ASU piloted an effort in the Kaibab National Forest that determined forest thinning on about 3,400 acres would generate a benefit of approximately 230 acre-feet, or nearly 75 million gallons, of water during the first year.

One acre-foot of water can provide water for three Arizona families for one year, the release stated.

Also, SRP and ASU are modeling projects in the East Verde River and East Clear Creek watersheds, which provide water to the town of Payson and are areas at high risk for catastrophic wildfires. Results from that investigation in the Coconino National Forest are expected later this year.

The researchers created a high-resolution map of the watershed – one that accounts for trees along with their height, size, and species using light detection and ranging survey and high-resolution photography of the land, according to the release. The LiDAR, combined with other image data, generated a precise, three-dimensional surface of the watershed.

SRP worked with Enrique Vivoni, director of the Center for Hydrologic Innovations at ASU, and graduate students and postdoctoral scholars from the center to combine the LiDAR results with other publicly available datasets to create a model of a thinning project area.

“Arizona is at a crossroads in terms of our water supply portfolio. Applied innovation projects, such as this effort in forest health and water resilience, translate research into actions for the benefit of our renewable water supplies,” Vivoni stated in the release.

"Not only does our work with SRP set the stage for regional impacts, it is also a successful model for how universities can collaborate effectively with water agencies and utilities."

SRP chooses forest thinning projects to fund based on several factors, including potential water benefits, reducing wildfire risk and protecting vital infrastructure and communities, according to the release.

The utility company works with the U.S. Forest Service and the Arizona Department of Forestry and Fire Management to collaboratively choose which forest thinning projects to focus on.

“The SRP-ASU innovative water model is applying research to real-world projects to help us understand the watershed benefits of forest thinning. This collaboration has proven to be invaluable as we continue to find ways to ensure water reliability during a record drought and shortages of other sources of water such as the Colorado River,” Elvy Barton, SRP manager of water and forest sustainability, stated in the release.

This research, conducted by the ASU Center for Hydrologic Innovation, is part of the Arizona Water Innovation Initiative. The Arizona Water Innovation Initiative is a statewide project led by the Julie Ann Wrigley Global Futures Laboratory in collaboration with Ira A. Fulton Schools of Engineering.

Through this initiative, ASU works with industrial, municipal, agricultural, tribal and international partners to rapidly accelerate and deploy new approaches and technology for water conservation, augmentation, desalination, efficiency, infrastructure and reuse, the release explained.