Milwaukee Considers Using Abandoned Basements to Hold Storm Water

Jul 10, 2014

Rather than just filling in former basements, the city wants to create covered spaces that could hold and absorb storm water.

Planners want to funnel storm water into basements of razed houses. The spaces would be filled in, yet hold water, when the sewer system is overrun.

There are blocks, especially on the city’s north side, where homes have repeatedly flooded during heavy storms. The sewer system there is older and sometimes backs-up, pushing water into basements.

The city also possesses hundreds of foreclosed, ruined properties. 

When Milwaukee demolishes an abandoned house, crews fill in the basement, but it might be put to better use by holding excess storm water, according to Erick Shambarger of the Milwaukee Office of Environmental Sustainability.

“It’s already excavated. It’s already lined with cement block, and so, the thinking was, can we convert that into a structure to take clean rain water off nearby rooftops or storm water off the street, treat it and hold it there. If it’s clean water from a roof, we can infiltrate it into the ground slowly and relieve some pressure on the sewer system,” Shambarger said.

Shambarger introduced the concept to a Common Council committee on Wednesday, during part of a broader discussion of how the city can better prepare itself for extreme weather.

He says the city had a company to review the basement idea, and engineers concluded it would be safe and cost-effective. They also offered proto-types.

“One design is to basically fill it with gravel and hold water in the void spaces, and then you put soil on top. Another one has what’s called storm water harvesting cells – they are glorified milk crates that you stack up that provide structure and have a lot of void space in them to hold water, and then we put a cover on it and top soil. So that when you look at these from the street, they will basically look like a vacant lot, totally covered,” Shambarger said.

Shambarger says a third option is to retain the first floor of a house and waterproof it. He says the Global Water Center in Milwaukee is helping research that option.

Alderman Joe Davis says he won’t discard the overall concept but wants planners to consider potential unintended consequences of turning foreclosed homes into retention ponds.

“Let’s not just go to the point where we demolish everything and create vacant lots and then we’re not creating this opportunity for long-term development for people who want to live in the City of Milwaukee,” Davis said.

City Hall hopes to win a grant to test its basement idea. Shambarger say many of the houses a program might target, were ruined by flooding.