Rain cisterns complete campus ‘runoff’ garden

6.The completed west cistern, with its overflow sluice, “feeds” the garden as a water feature when the cisterns are full. (View a gallery of images below.)

The completed west cistern, with its overflow sluice, “feeds” the garden as a water feature when the cisterns are full. (View a gallery of images below.)

Think of the two concrete cisterns placed behind Sabin Hall and the campus power plant as very large rain barrels.

“The purpose is not about capturing the water to irrigate the gardens there,” says Jim Wasley, associate professor of architecture. “It’s meant to slow the water rushing off the power plant roof during a storm. This will help to head off flooding in that area.”

Over the past year, Wasley has overseen the construction of the 20-foot cisterns, which are the final phase of the “spiral” garden that he designed.

Planted with deep-rooted native flora, the spiral garden, on the south end of the Klotsche Center, is primarily a stormwater management system, a natural method of slowing stormwater after heavy rains.

A ring of vegetated bioswales surround the parking lot adjacent to Merrill Hall and Norris Health Center, collecting water from the lot and from the disconnected downspouts of the surrounding buildings and channeling it to the spiral garden.

It is one component of Wasley’s “UWM as a Zero Discharge Zone,” plan to increase the number of green roofs and stormwater-mitigation strategies for the campus.

Together, the cisterns hold more than 12,000 gallons – the volume produced by roughly an inch and a half of rain across the 13,000-square-foot power plant roof. A sculptural upper outlet and a hidden lower outlet drain the cisterns over a 24-hour period following a heavy rain.

The cisterns include a pair of sluices – one conveying water into the system from the power plant and one that funnels overflow water from the cisterns into the 5,000-square-foot spiral garden.

Wasley and Carolyn Esswein, adjunct associate professor, have begun working on a concept for a similar natural storm water demonstration feature for the Southwest Quad of campus.

Funding for the cisterns was provided by Environmental Protection Agency’s Great Lakes Restoration Initiative, the Milwaukee Metropolitan Sewerage District, and the UWM Institute for Ecological Design in the School of Architecture and Urban Planning.

Since construction of the garden began in 2009, 18 research grant-funded students have contributed to the design and construction.

Anatomy of a Stormwater Garden

(Click on an image to enlarge.)