Green roofs could prevent sewage overflow in New York City

Brooklyn Grange, one of the biggest rooftop farms in the U.S.© Photo cred: Manon Verchot || Brooklyn Grange, one of the biggest rooftop farms in the U.S.

New York City’s sewage systems are old and can’t handle large amounts of snowmelt or stormwater. When large quantities of water flow into the combined sewer overflow systems, which make up 60 to 70 percent of the city’s sewers, they tend to spill over into New York City’s rivers.

It doesn’t help that the city is about 72 percent impervious, so water goes straight into drainage systems. Since May 2013, more than 45 incidents of sewage discharge have been reported. This past winter, untreated sewage overflowed into the Hudson and East Rivers on multiple occasions, sometimes for as long as seven hours.

But not all is lost. Rooftop gardens could be the solution, and New York City is working hard to help New Yorkers get their green on.

Brooklyn Grange, the largest rooftop farm and garden business in the US, is part of this initiative. The Brooklyn Grange itself spans 108,000 square feet, with locations in Queens and Brooklyn. The farms absorb 60,000 and 100,000 gallons of stormwater every rainfall.

“Over the course of the year, we’re keeping millions of gallons of water out of the sewer system,” Gwen Schantz, one of the founders and chief operating officer of the Brooklyn Grange, told TreeHugger.

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