By Maddie Orton
The garden on this Hoboken rooftop isn’t just eye candy for the residents above, it’s part of the city’s green infrastructure to combat stormwater runoff. And mayor Dawn Zimmer is pushing to see more of it—starting with City Hall.
“We want to try to be a model and show the community that there are different ways and different strategies,” says Zimmer, “but City Hall is going to be an example of how you could potentially disconnect your downspouts.”
The stormwater that rushes out of these downspouts and onto roads picks up copper from brake pads, fuel and chemicals. In urban areas like Hoboken, where there isn’t much natural ground to soak it up, that stormwater flows into the sewers and out to bodies of water, affecting the ecosystem.
Stormwater runoff is also a source of the city’s flooding woes. And it gets worse.
“We have a combined sewer system,” Zimmer explains. “So that means that if you combine sewage with all of the rainwater, we potentially get flooding because it’s just too much.”
That means stormwater in sewers comes back up onto the streets — and brings sewage along with it.
“We’ve tried to do as much as we can to go around and clean the streets after we get those heavy rain events, but it’s a health issue. It’s a quality of life issue,” Zimmer says.
So Zimmer is fighting nature with nature. She’s making the approval process easier for developers and residents to create green roofs. They collect runoff through soil and plants.
At the U.S. EPA office in Edison, a rain garden is on display in the parking lot. It’s a similar principle to the green roof — absorbing and filtering excess water — and also to educate decision makers, like Zimmer, and the public alike.
It also acts as a testing site for engineers to fine-tune the practice. They look at what size garden is ideal and take a page out of the Department of Transportation’s book on what plants survive well in both drought and heavy rain.
“Cities are spending a lot of money to control their stormwater,” says Michael Borst, an engineer for the EPA’s Office of Research and Development. “If we can do it cheaply and efficiently to help them, that would be great.”
Borst says there are benefits with green roofs that extend beyond stormwater management. Things like elongating the life of the roof and keeping the building cooler in the summer and warmer in the winter.
But, it doesn’t come cheap. According to Chris Mazzola of Bijou Properties, a green roof like this one with only about five inches of soil, can cost an additional $15 to $30 a square foot.
“If you’re looking at it strictly from an economic benefit, really there’s a large upfront cost,” Mazzola says.
This building is one of four properties with a green roof the company built in Hoboken.
“You know, you do see that pay back over several years,” says Mazzola. “And you also see it, not just on an economic perspective, but you also see it [in] a general occupant comfort of the building.”
Zimmer hopes to make green roofs a little more affordable down the road by enacting tax incentives as well. And, for do-it-yourself-ers who want to create their own personal rain garden, Borst says it can be done on the cheap with EPA-recommended plants and a little manual labor.