Mayor de Blasio has announced a major expansion of New York City’s Green Infrastructure Program. The City has already begun construction of more than 5,000 specially designed curbside rain gardens in Brooklyn, the Bronx and Queens, building upon the more than 4,000 rain gardens that have already been built.
This construction will bring a total of more than 9,000 curbside rain gardens to New York City, helping to prevent flooding and reduce Combined Sewer Overflows into local waterways by more than 500 million gallons each year, thereby further improving the health of New York Harbor and its tributaries.
“We are deploying all of the resources at our disposal to tackle the challenge of global warming head-on,” said de Blasio. “We are doubling the size of the largest green infrastructure program in the country, creating green oases in our neighborhoods and protecting our waterways for all New Yorkers to enjoy.”
More than 70 percent of New York City’s land mass is covered by an impervious surface, which creates tremendous volumes of stormwater entering the sewer system during rainstorms. Curbside rain gardens help to soften the city’s landscape and allow the stormwater to be naturally absorbed into the ground, therefore reducing flooding that can impact roadways, homes and businesses. By keeping stormwater out of the city’s combined sewer system, where it can contribute to combined sewer overflows into local waterways, the rain gardens serve as a tool in the city’s ongoing effort to improve the health of local waterways.
Some of the neighborhoods getting these rain gardens currently have less than average street tree counts and higher than average rates of asthma among young people. The increased tree canopy and vegetation created through the addition of the rain gardens is aimed at helping improve air quality, provide shade during hot summer months, and beautify the neighborhoods.
Rain gardens are built in city sidewalks and do not result in the loss of parking spaces. They resemble standard street tree pits, except that they vary in size, have curb cuts that allow stormwater to enter and overflow, and have been engineered in a way that will allow them to manage up to 2,500 gallons each during a storm. The rain gardens are designed so that all the stormwater is absorbed in less than 48 hours.
Increasing green infrastructure is part of New York City’s $20 billion strategy to address the impacts of climate change.