What’s a bioswale? (We know that’s what you’re saying to yourself.) It’s a curbside garden built to absorb stormwater. The city currently has about 255 of them, but will be installing an additional 2,000 throughout Brooklyn, Queens, and the Bronx to prepare for the possibility of more intense storms in the future. Not only will the bioswales absorb an estimated 200 million gallons of stormwater each year, but they’ll therefore mitigate pollution in the Bronx River, Flushing Bay, Gowanus Canal, Jamaica Bay and Newtown Creek.
You might be wondering why the city’s sewers can’t just do the job, but that system is aging and often sends massive amounts of dirty runoff into our waterways. To combat the issue, the NYC Department of Environmental Protection (DEP) developed designs for the bioswales, which include filling them up with hardy native plants. The four gardens that have already been installed near the Gowanus Canal, for example, will keep more than 7,200 gallons of stormwater out of the overburdened sewer system each time it rains.
According to the DEP, “Bioswales differ from standard tree pits in that they include curb cuts to allow stormwater to enter, use a permeable soil with a significant portion of sand to facilitate infiltration, and include an underlayer of gravel to increase storage capacity.” The project is part of the NYC Green Infrastructure Plan, which proposes a total investment of $2.4 billion in green infrastructure to improve harbor water quality over the next 20 years. It’s projected that the bioswales will be implemented by next summer and will cost $46 million.
Photos via NYC Water Flickr