The city has already started construction on 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.
“New York City is a national leader in protecting the environment and at the forefront of this work is the largest and most aggressive green infrastructure program in the country,” said DEP Commissioner Vincent Sapienza. “New York Harbor is cleaner today than it has been since the Civil War, and expanding our use of green infrastructure will help us continue to improve the health of all the city’s waterways.”
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 overflows into local waterways, the rain gardens serve as a tool in the city’s ongoing effort to improve the health of local waterways.
"There's no denying New York City has seen more and more rain every year, which puts us at greater risk of releasing of raw sewage from our combined sewer outfalls," said Councilman Costa Constantinides of Queens. "Curbside rain gardens are a vital tool in combatting this excess stormwater."
In addition, some of the neighborhoods getting the 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 will help to improve air quality, provide shade during hot summer months, and beautify the neighborhoods.
"Utilizing green infrastructure to capture stormwater and reduce sewage overflow is a critical tool to improve water quality in challenged areas like Newtown Creek,” said Willis Elkins, executive director of the Newtown Creek Alliance. “Additionally, the expansion of curbside rain gardens within our watershed will provide numerous environmental benefits for the communities that surround Newtown Creek via improvements to local air quality, wildlife habitat and the urban heat island effect."
Rain gardens are built in city sidewalks and do not result in the loss of any parking spaces. They resemble standard street tree pits, except that they vary in size, have curb cuts that allow stormwater to enter and overflow if it becomes saturated, 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 and dedicated maintenance crews ensure that they are functioning properly, including removing any trash that may have accumulated and pruning the trees and plants.
The crews are active seven days a week, visit each rain garden approximately once a week, and additional crews will continue to be added as the program expands.