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Harvesting Monsoon Rains
There are numerous water harvesting features integrated throughout the UA campus.
As University of Arizona students partake in recreational sports at Bear Down Field, it's unlikely they realize what lies just beneath their feet.
Under the north edge of the field lies a million-gallon tank designed to mitigate storm flows and harvest stormwater.
When monsoon clouds roll into town and unleash a downpour on the city, water is filtered into the tank, where it collects and, through a series of pipes, is directed outside of Likins residence hall, draining into the landscaping.
This tank is one of numerous water harvesting features integrated throughout the UA campus.
Water is arguably the most valuable resource in the Southwest. California is currently facing record-breaking heat, adding to its already shrinking reservoirs, and nearly 70 percent of Arizona is classified as being in a state of "severe" drought according to the U.S. Drought Monitor website.
With only 12 inches of rain on average per year according to U.S. Climate Data, and most of those 12 inches falling during monsoons, water harvesting efforts have become a critical practice in Tucson.
"In this region when we get large storms, the rain typically falls fast," said Grant McCormick, campus planner for UA Planning, Design and Construction and manager for the UA Enterprise Geographic Information System. McCormick is also a member of the Surface Water Working Group, a group of UA employees and students who support water-related projects on campus.
He said rapid downpours lead to lots of water in a short amount of time, creating a potential missed opportunity to use the water on-site, and often urban flooding as well.
"There's less permeable ground in the urban areas to absorb the water, so it tends to run off, concentrate, and lead to flooding," he said. "If the water's just running off, you're not harvesting it."
In the 20 years since he started handling the UA's surface water management, McCormick said he has witnessed a gradual evolution of incorporating water harvesting features into project designs.
"For our major capital projects, virtually all have a pretty significant water harvesting component," McCormick said, citing the UA's Environmental and Natural Resources 2 building, which includes a large underground cistern among its many green features.
McCormick is also an adjunct lecturer in the UA College of Agriculture and Life Sciences' Department of Soil, Water and Environmental Science, where he co-teaches a water harvesting class with Melanie Lenart, a technical expert researcher for the department. Students learn about active water harvesting – catchment in tanks for later reuse – and passive harvesting – letting the water fall to the ground and find its way into catchments by gravity.
Students in the course take on many hands-on projects across the UA campus in which they get to learn about stormwater harvesting and sustainable landscaping.
In 2007, they completed a landscaping project for the UA Visitor Center. Part of the design includes two large metal cisterns, located on the northeast corner of the lot. As water runs off the roof, it collects in the cisterns and can be used later for landscape watering. Students also took on a similar project at the Cochise residence hall, where most of the stormwater that would previously run off into Fourth Street is now redirected into basins.
This spring, students also helped enhance a community garden for Fourth Avenue's Food Conspiracy Co-Op.
"They wanted a citrus grove to grow fruit to sell in their store," McCormick said. "We did a layout for the water harvesting and the trees, and the students implemented water harvesting features for that citrus grove."
For those interested in adding water harvesting elements to their gardens or yards, McCormick said there are plenty of educational programs available, including the city of Tucson's Single Family Residential Rainwater Harvesting Incentives Rebate Program and the Conserve to Enhance program, a joint project of the UA Water Resources Research Center, Tucson Water and the Watershed Management Group. (Read more about Conserve to Enhance in this UANews article.)
"There's a lot of resources locally," he said. "There are classes and organizations out there that help people with water harvesting, and that's a real benefit to the community."