Image: Aloha Jon
Green Infrastructure
NYC's Green Infrastructure Plan
NYC's Green Infrastructure Plan was drafted by the NYC Department of Environmental Protection (DEP). It aims to install enough green infrastructure (GI) to manage the stormwater generated by one inch of precipitation from 10 percent of impermeable surfaces within the combined sewer areas by 2030. That means for every 100 acres of impermeable land, 10 acres of stormwater runoff must be managed with GI.
As they are currently written, the City’s long term control plans (LTCPs) assume the GI goals in each watershed will be met, but without any details as to how.​ If the information you are seeking is not in the Green Infrastructure Plan or your local LTCP, contact DEP directly.
The best way to prevent stormwater from overwhelming combined sewers or getting discharge directly into waterways is by keeping it out of the sewage systems in the first place. Green infrastructure and permeable surfaces allow stormwater to be filtered and drained. This curbside garden is just one example.
Green Infrastructure
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Green infrastructure (GI) uses ecological systems, such as soil and plants, to reduce and eliminate stormwater entering the sewer system. GI, in other words, serves as source reduction. It can capture stormwater runoff from rooftops, sidewalks, and roads through rain gardens, roadside plantings, and green roofs. GI prevents polluted stormwater from draining into our waterways and decreases the frequency of combined sewer overflows (CSOs).
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Is there a GI plan for your watershed?
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Green infrastructure has many additional benefits, such as filtering the air, lowering surrounding ambient air temperature, and providing habitat for wildlife. GI can also be distributed throughout the watershed, so those benefits can be spread through many neighborhoods. View GI project maps and plans on the DEP website.
Grey Infrastructure
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Grey infrastructure modernization is also a critical part of improving water quality. Increasing sewer system pipeline capacity prevents overflows. This includes:
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wider tunnels
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storage or retention tanks that can hold excess water temporarily
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sewer separation: separating wastewater and stormwater sewers
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re-routing flow within the sewer system
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Financing Green Infrastructure
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From the very beginning of its formation, SWIM has been advocating for property tax abatements for NYC property owners that install green roofs and GI projects. Green roofs reduce the volume of raw sewage flowing into the city’s waterways by retaining stormwater, while cooling the city’s air, improving air quality, saving energy, and supporting biodiversity.​
DEP's Green Infrastructure Plan committed $187 million to GI through a legally binding agreement with New York State in order to meet Clean Water Act requirements. With improvements to designs and increasing greenhouse-gas reduction goals, NYC policies should be continually assessed to ensure they are meeting current needs.
SWIM Wins
The 2008 green roof tax abatement, providing a $4.50 per square foot property tax abatement up to $100,000 for most private building owners
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Local Law 5 of 2008, requiring the City of New York to develop a Sustainable Storm Water Management Plan
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The “Minds in the Gutter” green infrastructure design competition, raising awareness of green infrastructure to hundreds of professionals citywide