Dec 04, 2009

Flowers for Showers

The Daniel F. and Ada L. Rice Plant Conservation Science Center, the newest addition to Glencoe, Ill.’s, Chicago Botanic Garden (CBG), will serve as a laboratory and research facility for CBG staff and their various partners. Opened in September 2009 and designed to earn Leadership in Energy and Environmental Design Gold certification from the U.S. Green Building Council, the building will broaden its function, managing storm water in an observable, innovative fashion and educating the public in the process.

The rainwater glen functions like a river’s floodplain.

Rainwater Glen

Situated on 4.5-ft pillars, the 38,000-sq-ft science center sits over and is surrounded by a rainwater glen—a rain garden/bioswale hybrid designed to function like a river’s floodplain, according to Bob Kirschner, CBG’s curator of aquatic plant and urban lake studies.

Some storm water runs off the science center’s 16,000-sq-ft green roof, but most is soaked up by its abundant plantings; a nearby road and parking areas generate the vast majority of the site’s runoff. The rainwater glen, comprised of native “workhorse” plants—Acorus calamus (sweet flag), Iris virginica (blue flag iris) and Zizia aurea (golden alexanders), for example—holds back this runoff and helps filter impurities.

The new facility is underlain by tight clay soils that Kirschner compares to a layer of saran wrap. This composition limits the rainwater glen’s ability to infiltrate water, but between evaporation, evapotranspiration, thirsty vegetation and an underground drain tile system, it contributes somewhat to runoff reduction and likely appreciably to onsite and downstream water quality. CBG staff recently began conducting nutrient analyses to help quantify the feature’s water quality benefits.

“It’s not just a symbolic gesture to the environment,” Kirschner said. “In every way, it can make a meaningful contribution to storm water.”

Kirschner guides SWS Managing Editor Caitlin Cunningham.

Teaching Tool

A 40-ft bridge crosses over the rainwater glen, leading visitors to the science center’s entrance. Public education signs line the way to illustrate and describe the rainwater glen’s purpose, components and operation.

“One of the key things to emphasize with a rain garden is the second word: It’s a garden,” Kirschner noted. “Not all environmental features are lovely and beautiful and work really well in our yards, and this is one that is. [A homeowner] could be reducing the runoff coming off a property by 10% or 20% just by having one downspout discharge to a rain garden.”

During the building’s opening weekend, CBG staff handed out reference materials and encouraged people to get started, however gradually.

“Start small, decide that this is good for you, and you can always add more rain gardens to your landscape or choose to make the one you’ve already constructed a bit larger,” Kirschner said. His advice to the public is an important statement for the CBG as well, as the construction of the science center and its storm water features was Phase I in the implementation of plans for a 15-acre science campus.  

Editor’s notes:

  • Editorial Director Neda Simeonova will profile the aforementioned Daniel F. and Ada L. Rice Plant Conservation Science Center green roof in the January edition of SWS RunOff.
  • In last month’s edition of SWS RunOff, the incorrect photos ran with the article “Campus Designers Look to Underground Solutions.” View the correct photos at

About the author

Caitlin Cunningham is managing editor of Storm Water Solutions. Cunningham can be reached at 847.391.1025 or by e-mail at [email protected]