• SWIM

How's NYC's Green Infrastructure Program Performing?

Updated: 4 days ago


The City's Green Infrastructure (GI) Plan, introduced in 2010, has a specific set of stormwater management milestones to meet (every 5 years) in order reach NYC's 2030 goal of reducing combined sewer overflow (CSO) pollution* in our waterways.


The overarching goal for the GI plan is for NYC to be able to manage, with green infrastructure, the equivalent of stormwater runoff generated by 1 inch of precipitation, across 10% of the impervious surfaces in the combined sewer area of the city by the year 2030. This translates to installing GI on about 8,000 acres by 2030. So far, we've "greened" 1,230 acres.


The NYC Department of Environmental Protection (DEP) is the agency that implements the GI Plan. They issue an annual report every year to update the public on their progress.DEP issued their 2019 report for the GI Plan in August, 2020.


Though the program has made positive progress installing GI (mostly in the public right of way and on public property) throughout the combined sewer area of the city, the 2015 and 2020 milestones for the plan have not been met.


  • The 2015 milestone of managing stormwater volume on 1.5% of the designated impervious area was missed, as was the 2020 milestone of managing stormwater on an additional 2.5% of the designated impervious area. DEP is scheduled to publish a contingency plan this year for how they will make up for missing the 2020 milestone and catch up to the 2025 milestone. The upcoming 5 year milestones are: an additional 3.5% by 2025 and a final 3% by 2030 in order to get to the 10% impervious area goal.

The first 5 years of the program, which focused on high priority zones in the combined sewer drainage area, presented an array of challenges that were not fully anticipated. DEP had to adapt and evolve the program in response to the challenges.


As of 2019, the program currently has ~10,000 assets either in the ground or in construction, mostly on publicly owned property. The types of GI in the program range from rain gardens and infiltration basins in the public right of way, permeable playgrounds at parks and public schools, and 2 permeable pavement pilot projects.


The rain gardens in the public right of way faced some maintenance challenges that had to be rectified and the public right of way itself has posed its own set of challenges. Installing rain gardens in the public right of way (i.e sidewalks and traffic medians) has been challenging due to the amount of infrastructure that is underneath our streets: subway lines, gas lines, drinking water lines, cable lines, a high bedrock tables in some areas of the city and high water tables in others.


In some cases, rather than a full rain garden and especially in some industrial areas, the city has installed infiltration basins in the public right of way, while these are not as visually "green" as rain gardens and have less of the typical greening co-benefits of cooling the heat island effect and beautifying the area, they capture and manage the same amount of stormwater as a rain garden (2500 gallons every time it rains) and require less maintenance.


Nearly 50% of the total surface area that the city has targeted for GI is on private property. While there is more GI yet to be installed on publicly owned property, the next decade will require a focus on incentivizing GI on privately owned property that is with in the combined sewer area of the city.


In 2016 and 2017 DEP received stakeholder recommendations for ways the city could incentivize GI on private property. In 2017, SWIM Coalition member NRDC, in coordination with the NYU Stern Center for Sustainable Business, compiled the recommendations in a comprehensive report, Catalyzing Green Infrastructure on Private Property which contains many of the recommendations that DEP is now implementing. Here is a link to the 2017 report.


DEP's 2019 Annual Report highlights several programs, recommended in the 2017 report mentioned above, that DEP expects will incentivize private property owners to install GI in the years ahead. Below is a brief overview of the incentives + a state level tax abatement program that SWIM was instrumental in initiating in 2007.


  • DEP has a grant program to support the installation of green roofs on private property retrofits within the combined sewer area of the city. The program has a 15 year restrictive covenant for maintenance that has deterred widespread use of the grant. So far the program has supported the installation of 30 GI projects at a cost of $13 million. The program recently shifted to green roof retrofits only to better align with the recent enactment, in 2019, of two new NYC Green Roof Laws.


  • DEP will introduce a new Private Property Retrofit Incentive Program in 2020, that will be managed by an outside administrator, to support the installation of GI projects on existing properties citywide that are 50,000 square feet and larger. DEP has set aside $53 million dollars to support the program and has a goal of greening 200 acres through the program.


  • DEP will introduce a Unified Stormwater Rule in 2021 that will catalyze more GI on new development and redevelopment sites citywide. SWIM is excited about this new rule and there are many stakeholder recommendations for how this rule can be most effective! We look forward to providing public input on the rule in the coming months and in the year ahead. You can read more about the new rule here.


  • The NY State Green Roof Tax Abatement program has recently been revised and renewed. Here is a SWIM blog post on the current program. While not part of the GI plan, the green roofs installed under the plan in NYC will count toward the 8000 acre 2030 goal.


  • The 2017 report mentioned above contains recommendations for DEP to equitably restructure the city's current water rate (as nearly 1400 other municipalities across the country have done in recent years) so that the city can accurately bill a property for the amount of stormwater runoff it actually generates. There are some important steps that DEP has to take before they are poised to make the rate structure changes.

Starting in October 2020, DEP is conducting a water rate study to explore

equitable restructuring scenarios. SWIM has made a series of recommendations

for robust public engagement with the study which you can read about here.

Our coalition members, NRDC and Riverkeeper have developed a rate

restructuring modeling tool and published a report to demonstrate the types of

restructuring scenarios that would yield an equitable restructuring of NYC’s

existing sewer/wastewater charges in NYC.


All in all, NYC is dedicated (to the tune of $1.5 billion) to the use of Green Infrastructure to help manage the enormous amounts of stormwater volume generated by our nearly 72% impervious landmass every time it rains more than a tenth of an inch. We will certainly need to stick to the 2030 goals and milestones of the GI plan and the city's other CSO reduction and stormwater management plans if we are to be prepared for what we know lies ahead in the face of Climate Change.


SWIM will continue to monitor the GI Plan and support other important initiatives to increase our climate resiliency in the years ahead. Be sure to sign up for our monthly e-blasts to stay up to date!






*Combined sewer discharges are the largest ongoing source of pollution in NYC's waterways. The city's antiquated combined sewer system gets overwhelmed during wet weather events ( sometimes as little as one tenth of an inch can trigger an overflow) and currently discharges about 20 billion gallons a year of combined sewer overflow: polluted stormwater runoff mixed with untreated sewage from our homes and buildings, into our waterways each year. Yuk. The City's GI plan and CSO Long Term Control Plans are guided by a 2012 CSO Consent Order agreement between the City and the NY State Department of Environmental Conservation (DEC). The GI Plan and CSO LTCP's are meant to reduce the 20 billion gallons of CSO by 1.67 billion gallons by 2030 through a combination of grey and green infrastructure initiatives.

2 views
  • Instagram - Black Circle
  • Facebook - Black Circle
  • Twitter - Black Circle
Search the Site
Never Miss an Update

SWIM Coalition is sponsored by the NYC Soil & Water Conservation District and Riverkeeper, Inc. Your donations to SWIM's work are tax deductible under the IRS code170(c)3. 


Donations to SWIM are managed by Riverkeeper, Inc.