Turf battle: Hydrogels could help ASU West save water and money

Arizona State University and Phoenix are working together to conserve water. The city’s Water Services Department received a grant to test out biodegradable hydrogels, which hold water at the root line.

By Mariah Gallegos and Austin Grad

GLENDALE – Arizona’s notorious dry heat can make it tough and expensive to keep playing fields green without wasting water. That’s why Phoenix Water Service Department officials are injecting conservation technology known as hydrogels into soccer fields at Arizona State University’s West campus.

The school and the city have teamed up to use a $100,000 grant to pilot the injection of hydrogels – small, granular saltlike elements that can absorb up to 500 times their weight in water – under the turf. Once hydrogels absorb water, they can dispense up to 96% of it, which could make them an effective tool for conserving this most precious resource.

“A machine takes (the hydrogel) and places it approximately two inches below the root zone of the grass or the turf,” said JoEllen Alberhasky, program manager in sustainability practices at ASU. “It’s biodegradable and so it’s organically, environmentally safe. The hydrogel holds that water right there below the root zone and allows the grass to take a drink from it whenever it’s thirsty.”

The potassium-based hydrogels, which last five to seven years, help reduce soil erosion and runoff while retaining moisture, she said. This increases water retention, which can allow plants to survive during times of drought.

Alberhasky noted that a yearlong test of hydrogels in fields in California’s Central Valley reduced water use 45%. The Central Valley is the agricultural heart of California, and farming there relies on economical use of water, particularly during persistent droughts. The test was conducted by the Center for Irrigation Technology at California State University, Fresno, which has tested hydrogels on campus landscaping for several years.

Alberhasky said the technology could get similar, if not better, results in the Phoenix area.

Kathryn Sorensen, director of Phoenix Water Services, envisions major savings from hydrogels.

“If this technology works,” she said, “we might save as much as 40 percent of the water that it takes to keep a turf facility healthy. That’s a pretty significant savings so we’re hoping that this pans out.”

The soccer fields at ASU West consume nearly 11 million gallons of water per year, which costs the city and university about $63,500. A 40% reduction in water usage could save more than 4 million gallons and $25,000 each year.

Alberhasky said this technology can help address the ongoing drought in Arizona.

“It is another tool besides good, effective irrigation and smart watering to make sure that we get the grass the water it needs, but we don’t waste any of it. It allows us to be really efficient,” she said.

If the hydrogel pilot works well, Phoenix could expand its use to parks and golf courses.


Video by Mariah Gallegos/Cronkite News

This story is part of Elemental: Covering Sustainability, a multimedia collaboration between Cronkite NewsArizona PBSKJZZKPCCRocky Mountain PBS and PBS SoCal.

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