An Age-Old Challenge: Keeping Rain from Going Down the Drain

Two Roaring Twenties-era structures in the Chicago area are meeting that challenge by collecting and conserving stormwater on a grand scale.

Dominican University

In 2007, while hammering out the blueprints for a new science building, Parmer Hall, Dominican University in suburban River Forest, IL, discovered a perfect source of water for air-conditioning the new structure: a cistern dating back to the 1920’s buried under planks and debris in the basement of the old science building nearby. Mothballed and hidden from sight for half a century, the huge, 60,000-gallon concrete cistern was once the repository of rainwater from campus gutters and downspouts. That water was then pumped into the municipal sewer.

Project engineers and architects had a “eureka moment” when they realized that the abandoned cistern, under what is now the Magnus Arts Center, could be reactivated and expanded to collect water campuswide. Not only would all this free water help cool Parmer Hall, but it could also be used to keep Dominican's ballfields and lawns green. Moreover, why not add a well to supply water even during dry times? And voila! They connected the cistern to a new well and a labyrinth of underground pipes that circulate water to Parmer Hall's mechanical water works, and to the university irrigation system.

Thanks to this imaginative reuse of an old technology, coupled with other features that capture rain before it escapes offsite---a bioswale plus over 200,000 square feet of permeable paving in school parking lots----the university saves a whopping 6 million gallons of water per year.

Old Post Office

Against all odds, the old Main Post Office in the heart of downtown Chicago has been brought back from the dead after sitting idle for over two decades. Filled with antiquated mail-sorting machines and haunted by the ghosts of old postal workers, the historic landmark, built in 1921 and expanded in 1932, was gutted and reopened in 2019. It has a long list of energy- and water-saving features: a fancy Building Automation System, LED lighting and motion detectors, low-flow toilets and aerator-equipped faucets, even a supplemental cooling system fed by the adjacent Chicago River.  

Topping off the makeover, a 3.5-acre rooftop park crowns the behemoth building that is now the home of Walgreens and several other businesses. Employees on their lunch break walk down paths winding through fields of native perennials and grasses. Over 40,000 individual plants, representing more than 50 species, grow in a specially formulated, six-inch lightweight soil mix that doesn't overload the roof. (Much of the rooftop material was flown in by helicopter, just as mail was delivered to the roof 70 years ago!)

Like a mega-sponge, all that greenery sucks up as much as 250,000 gallons of stormwater and prevents it from entering the City’s storm sewer. As an extra bonus, it filters out pollutants. The rooftop garden has its own irrigation system which runs at night in order to minimize evaporation. 

To add to the building’s green buzz, three colonies of bees have set up shop on the rooftop as well. The Post Office renovation boasts LEED Gold certification.