Hazel Cox, right, works with students from her rainwater harvesting class outside the University of Arizona nursing building. The students are learning to construct berms to direct and collect water.


UA students are installing rainwater-harvesting systems in a class that helps the campus continue to improve its environmental sustainability.

The class initially worked on the University of Arizona's oldest building, Old Main, which was sinking into the ground. Rainwater would run off the roof and puddle at the bottom of the building, but the land was too flat for the water to move, so it soaked into the ground and weakened the foundation.

The students designed a system to "bring water away from the building and into little basins so that it would soak in near the vegetation," said Jim Riley, then a professor in the soil, water and environmental science department. He has since retired.

Riley began teaching the course after it was created by Chet Phillips, an undergraduate at the time, in 2006. Phillips is now a doctoral student in the UA's Arid Lands Resource Sciences program.

"In my view, UA ought to serve as a kind of learning laboratory for how we live appropriately in the Sonoran Desert," Phillips said.

The two decided that the class should have a "hands-on" component, requiring students to complete rainwater-harvesting projects around the campus.

The most common technique is known as passive rainwater harvesting. Swales and berms direct rainfall from roofs to trees and plants before it runs off the landscape.

In active harvesting, by contrast, gutters and downspouts channel rainfall to large storage cisterns.

So far this semester, the class has been working on basic concepts in the large dirt basin between North Campbell Avenue and the College of Nursing building.

Danielle Cooper, a sophomore majoring in sustainable plant sciences, said she recommends the class.

"Even if you're not into rainwater harvesting or agriculture, it's a really good class for anyone because it teaches you the basics of rainwater harvesting in the simplest way.

"If you want a cheaper water bill or even if you want to live better, think about harvesting rainwater."

The rainwater-harvesting course has also worked on campus landmarks like the UA Visitor Center, which includes active and passive harvesting, the Rec Center and Cochise Residence Hall.

Rainwater harvesting also helps control flooding, which erodes streets, and it helps combat the urban heat-island impact, according to Fernando Molina, a Tucson Water spokesman.

Man-made structures such as streets and buildings hold heat in, making them warmer than surrounding areas. Rainwater harvesting, however, enables the city to plant more trees without using more potable water, which creates shade and decreases the heat-island effect.

Riley said that, on average, "a homeowner uses a third to a half of the potable, fresh water that they consume for irrigating."

Students gain valuable experience in the class, said Hazel Cox, who teaches the course.

"Once you understand the basic concepts and how to direct the water," Cox said, "it is really easy and fun, and everyone can do it and should be doing it in Tucson, because it would solve so many water issues."

She said she's unsure of where the class will end up installing a system this semester.

Molina said the UA "really has taken a big lead in this." He also said the class "is doing some innovative work." The UA uses a combination of well water and water from Tucson Water.

Phillips said that he's seen a change since the course began.

"As these projects continue," he said, "you start to actually make UA more sustainable in its water use and a better example in the Tucson community."

Rain Harvesting

• Active rainwater harvesting: uses gutters to direct rainwater from rooftops to large tanks for storage.

• Passive rainwater harvesting: gently reshapes the landscape to direct rainwater to irrigate plants.

• Since 2008, Tucson has required new commercial developments to meet at least half of their landscaping needs with harvested rainwater.

• Tucson Water offers rebates to customers who attend a workshop and install a system. For passive harvesting, customers are eligible for a maximum rebate of $300 - for active, up to $2,000.

• It is possible to collect up to 600 gallons of rainwater from a 1,000-square-foot roof during a 1-inch rainstorm.

To read more, visit UA's Cooperative Extension on urban rainwater harvesting: cals.arizona.edu/pubs/water/az1566.pdf

Drew McCullough is a University of Arizona student who is an apprentice at the Star. Contact him at 573-4117 or at starapprentice@azstarnet.com