Harvesting Monsoon Rains

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.

Read the rest August 28, 2014 UANews article at the link below.

Date released: 
Sep 9 2014