Flooding in basements might be a happy occurrence, if we walk in the watery footsteps of Milwaukee.
As part of a new citywide sustainability plan, Milwaukee is making innovations to its water systems in an attempt to reinvent itself as a “fresh coast” capital. One project in particular tackles the annual problem of stormwater management. The city recently released a feasibility study proposing turning vacant basements into cisterns. The idea is the brainchild of Erick Shambarger, the deputy director of the City of Milwaukee Office of Environmental Sustainability.
We are making good use of a hole in the ground.
— Erick Sharmbarger
After Milwaukee experienced major storms and subsequent flooding in 2008, 2009 and 2010, the city put together a Flooding Study Task Force. The mayor appointed Shambarger to the task force, which often discussed how to keep water out of people’s basements. Milwaukee has a combined sewer system that collects both domestic waste and rainwater runoff, so when street flooding would overwhelm the sewer system, water and sewage would back up through the floor drains in people’s basements.
While looking at a map of where the basement flooding was worst, Shambarger noticed that the location overlaps with the center of the city’s foreclosure crisis. Hundreds of these foreclosed houses cannot be economically salvaged and are being razed by the city. Cue Shambarger’s lightbulb.
As part of the Great Lakes region, Milwaukee sits on approximately 21 percent of the world’s surface freshwater supply.
“If we are going to demolish the house anyway and there’s going to be a vacant lot there, why not keep the basement portion of it?” he says. “Let’s get water into those basements and in the process keep other basements dry. We are making good use of a hole in the ground that somebody put there for us.”
Shambarger and his team called the idea a “BaseTern” and trademarked the name on behalf of the city. Curtis Hulterstrum, the senior water resource engineer at HNTB Corp., was tasked with preparing the project’s feasibility study. The study examined multiple options for how the basements could be converted and the way BaseTerns would manage stormwater.
Essentially, the basements will be used to immediately take the pressure off the sewage system, by diverting and holding street and roof water “runoff” until the storm is over. Water would flow into the structure, which would be covered with turf grass, via drains on top of the basement. It could flow out of the basement into the sewer system via the standard floor drain, through a riser pipe attached to the drain, by adding multiple holes in the basement floor to allow some water to sink into the ground safely, or by a combination of all of these. The study also considered how the BaseTerns could work with surface gardens, a project the city is looking at to promote urban agriculture. Rain barrels could be placed on top of the basement, harvesting rainwater for the surface gardens or other urban agriculture.
The city recently opened a Global Water Center, which houses water-related enterprises and startups along with academic programs from the University of Wisconsin-Milwaukee’s School of Freshwater Sciences. “We are using water as a driver for economic development,” says Shambarger.
Water lawyer Kevin Patrick took a look at the feasibility study and says he finds it “highly doubtful” that stormwater could be controlled in this manner, particularly in a way that is more economical than traditional stormwater solutions. Perhaps, but when I shared Patrick’s doubts with Hulterstrum, he noted that the feasibility study was schematic. He says that, depending on how you configure the outlet pipes, the system can be “designed for as much water for as long a period as you want.” Hulterstrum added that the costs will vary depending on the complexity of the BaseTern.
As far as a detailed cost-benefit analysis goes, the next step will be building a pilot BaseTern. Shambarger hopes to do this by next year’s rainy season in May. The Fund for Lake Michigan paid for the feasibility study, and executive director Vicki Elkin says she’d be open to considering funding the pilot program as well. She says not only do they need to see how this plays out when the BaseTerns are constructed, but it’s important to see how this may be replicated in other areas of the city. “What I’m hearing from engineers is that it’s really place-dependent,” she explains.
David Waggonner, a water expert in New Orleans, says the idea sounds like a “worthy experiment.” He adds, “I hope that it’s a scale that will be replicable.” Hulterstrum and Shambarger say the city has been getting a lot of interest surrounding the project, especially from other cities in the Great Lakes region.
If Milwaukee finds success in the BaseTerns, it would be a big step up in the city’s initiative to become a water technology hub. And to think, the idea came out of foreclosed homes and sewage-backed-up basements.
Way to think outside of the (flooded) box, Milwaukee.
Why you should care
With storms getting stronger every year, cities around the world are devising creative solutions for controlling and living with water. Milwaukee is the latest to throw its water-soaked hat in the ring.