Scientists hope vacant lot gardens keep water clean

Kim Kozlowski
The Detroit News

Detroit — Not long ago in the middle of a Detroit street sat two vacant homes that attracted vandals and blight and disrupted the neighborhood’s ecosystem.

Today, the lots on Evergreen south of Joy are home to a garden designed to keep pressure off the city’s wastewater treatment system and protect human health while beautifying neighborhoods.

The project — which includes three other gardens in the Cody Rouge neighborhood on the city’s west side — is led by Joan Nassauer, a professor of landscape architecture at the University of Michigan. She and 10 other scientists are partnering with the Detroit Water and Sewerage Department and the Detroit Landbank Authority, which owned the two homes, on the project.

Each garden is designed like a shallow basin, with 10 feet of permeable material that is holding stormwater below the ground. The four gardens are expected to reduce the annual volume of stormwater by 1.2 million gallons annually. This is critical, Nassauer said, because when it rains, too much water gets into the city’s storm and sanitary sewer system. If the system becomes overloaded, untreated runoff water — including sanitary sewage — gets dumped into the Rouge River.

“If during a storm we can keep much more water here just below the ground, that reduces the pressure on the city’s system and so there won’t be a big untreatable amount of water that comes into the system,” Nassauer said. “If untreated water ends up in the Rouge River, it carries pollutants that reduce biodiversity, and can make it more difficult for people who live downstream to get their drinking water from the lake.”

A good example of how untreated pollutants can turn into a public health crisis occurred last year when a toxic algal bloom in Lake Erie made the water unfit for drinking for more than 500,000 people in southwest Michigan and in the Toledo area.

“The Rouge River and the Detroit River was a part of the cause of that problem,” Nassauer said. “So we are trying to reduce water pollution so that biodiversity in the lakes (can be preserved), but importantly human uses of water in the lakes for drinking can be protected.”

The gardens project is also expected to reduce local flooding and enhances the neighborhoods when the shrubs and flowering perennials bloom next spring.

It was funded with $285,000 from the U-M Water Center with support from the Erb Family Foundation, along with $500,000 from the Detroit Water and Sewerage Department.

“Projects like these are going to be extremely important as we move forward in the city,” said Palencia Mobley, deputy director and chief engineer at the water department. “They allow us to make use of vacant land and to make it more productive, while at the same time eradicating blight in the neighborhoods.”

Some neighbors of the recently completed Evergreen garden, such as Ron Baldini, think the project is a waste of money.

“This neighborhood could use a lot more than a garden,” said Baldini, adding that if the street were fixed, the basin wouldn’t be needed. “Why didn’t they put a playground here for all the kids in the neighborhood? There is so much more that could have been done.”

But James Scruggs appreciates the foliage.

“I think it’s going to offer great images for the community,” he said. “I hope we can walk past this and know people are thinking about and care about our neighborhood and hopefully we inspire others to take care of their property too.”

There are people all over the world working on green infrastructure, Nassauer said, but this is a unique project in the world of science.

“What we’re doing here is we are not just measuring what a city utility is doing in green infrastructure,” she said. “We are collaborating closely with the city at the beginning to say how you can do it to get the most out of it.”

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