May 7, 2025

Nature-Based Solutions for Climate Resiliency and Disaster Preparedness

Good afternoon, Chair Gennaro and members of the Committees on Environmental Protection, Resiliency, and Waterfronts. I am Angela Licata, Deputy Commissioner of Sustainability at the Department of Environmental Protection (DEP). I am joined today by Deputy Commissioner of Public Affairs and Communication Beth DeFalco and several other colleagues from DEP and the Department of Parks and Recreation to talk about nature-based solutions for climate resilience and disaster preparedness.

DEP has a long-standing history of using nature-based solutions to improve harbor water quality. Newer systems focus on managing stormwater in areas that are prone to flooding. Nature-based solutions can be advantageous when they are brought on-line more quickly and with less construction disruption than long-term sewer construction. They can also have meaningful local improvements, like creating natural habitats for local wildlife.

Before we talk more about these tools, we should talk about our changing climate.

Stormwater

Climate change is bringing more severe and frequent rainstorms to New York City. In 2020, NOAA reclassified New York City from a “coastal temperate” zone to a “humid subtropical” climate zone — a recognition that we now live in a different world than we were in a few decades ago.

These more severe rainstorms have brought new challenges to our stormwater management system.

Sewers (Gray Infrastructure)

Traditionally, sewers (often referred to as “gray infrastructure”) are the main line of defense in a storm. New York City has approximately 7,500 miles of sewers, which were designed to effectively manage stormwater for a temperate climate.

Our sewers continue to protect fully against 98% of rain events, but the system is not designed to handle the most extreme storms we now face. The sewer system can get overwhelmed when the amount of water produced by the storm is greater than the capacity of the pipes. That generally means that most of sewers can handle between 1.5 and 1.75 inches of rain per hour. This used to be rare for most of the city but is now a regular occurrence.

We have to expand our stormwater management system if we want to meet the needs of today, let alone tomorrow. Upsizing sewers alone is not financially and logistically feasible.

Building above ground is almost always cheaper and faster than building below. Our best strategy is to use a combination of both gray and green infrastructure in the right place and measure.

Green Infrastructure

Green infrastructure absorbs water into the ground in areas with good soil. It can also green neighborhoods, improve air quality, reduce extreme heat, and provide habitats for pollinators.

What green infrastructure can’t do alone is capture and move as much stormwater as our sewers. And can’t be used everywhere. Because the systems rely on water infiltrating naturally into the ground, green infrastructure can only be used where soil conditions allow infiltration. If an area is mostly bedrock or has a high groundwater table, for example, the water cannot be absorbed.

There are many forms of green infrastructure, including rain gardens and infiltration basins, large scale median projects, porous pavement, daylighting projects, and cloudburst management systems. We have installed these assets in public right-of-way areas, in partnerships with Parks, schools, and others, and have facilitated installations on private properties as well.

Our green infrastructure program started in 2012 to mitigate combined sewer overflows (CSOs). CSOs occur when combined sewers (those that manage both stormwater and wastewater) are inundated with so much stormwater that the system’s capacity is exceeded and untreated water is released into a local waterway.

What we found is that green infrastructure also reduces street flooding by capturing and slowing stormwater before it enters the sewer system, freeing up drainage capacity and reducing CSOs.

A few years ago, we started to identify opportunities where we could site and design green infrastructure to go above and beyond CSO reduction to help our sewers perform in areas where additional storage can reduce flooding. You’ll find these strategies in large, underutilized medians and also as part of our cloudburst management program that we’ll discuss below.

With over 16,000 green infrastructure assets constructed and over $1.4 billion committed, the NYC Green Infrastructure Program is now the largest of its kind in the nation and continues to grow. In 2024 alone, we added 2,500 green infrastructure assets in our city through a combination of rain gardens and infiltration basins in our sidewalks, as well as new green infrastructure on public and private lots.

Different Types of Green Infrastructure and Nature-Based Solutions

In keeping with the topic of the hearing today, I would like to tell you a little bit about how DEP uses nature-based tools and discuss implementation challenges.

Bluebelts

DEP’s Bluebelt program dates back to the early 1990s. Bluebelts are ecologically rich stormwater best management practices that work in tandem with our sewer infrastructure. They incorporate natural or engineered water features such as streams, ponds, and wetlands to convey, store, filter, and slow the flow of stormwater to manage and alleviate/prevent flooding. As an added benefit, Bluebelts include open spaces with native vegetation that reduce runoff and pollution and provide wildlife habitat.

As Bluebelts use wetlands and ponds to manage stormwater, they are primarily sited at locations with existing waterbodies and separate storm sewer networks. Most of them are on Staten Island, because Staten Island has more intact watercourses and waterbodies than the other boroughs. Over the last ten years, DEP has built Bluebelts for approximately one third of Staten Island’s land area. In Staten Island, we are continuing to build out Bluebelts in New Creek, Lemon Creek, Arden Heights, and Butler Manor watersheds. USACE is commencing construction of Bluebelts in South Beach Watershed of Staten Island as part of the interior drainage of their South Shore of Staten Island Seawall.

DEP has completed 96 Bluebelts assets across three boroughs. In addition to Staten Island, DEP has created some Bluebelts in Queens and the Bronx and is looking to expand the program in other boroughs. DEP is currently analyzing potential Bluebelts sites for implementation in the current 10-year plan.

DEP looks for opportunities to implement Bluebelts in watersheds near to flood-vulnerable areas. Many times, these flood vulnerable areas are nearby or within existing or historic waterways. These are often located on NYC Parks property, so DEP is partnering with Parks to identify opportunities where parkland could provide the space necessary to detain stormwater. Where there is no obvious Parks partnership, DEP looks for other city-owned or vacant land opportunities.

In addition to the stormwater and flooding benefit, the Bluebelt program is also a community amenity. The majority of Bluebelt sites are open to the public and offer an open space experience. The public can access the sites via gravel walking paths that afford access to green spaces rich with wildlife, wildflowers, and wetlands. The program also leads multiple educational tours each year and hosts an annual citizen science project where local students learn hands on about fish migration, water quality, and scientific methods. A popular Adopt-A-Bluebelt project gives the community an opportunity to get involved by adopting sites and keeping them free of litter and weeds. The Bluebelt program also supports local community groups each year by sponsoring clean-up events on City properties.

Rain Gardens, Green Medians, Porous Pavement

Green infrastructure comes in a variety of shapes and sizes, including curbside rain gardens, greened medians with underground stormwater retention, porous pavements, and infiltration basins.

Each of these installations, or assets, allows water to flow in and then seep through layers of engineered soil and stone into the ground underneath.

We have installed more than 16,000 green infrastructure assets in public right-of-way (ROW) areas around the city. The majority of these (about 7,000) are rain gardens.

We are building more than just the rain gardens you see in our sidewalks and porous pavements on streets. We have also retrofitted over 250 public parks, playgrounds, and NYCHA properties with green infrastructure and we have over 100 additional properties in planning and design. This includes projects funded through our public-private partnership with the Trust for Public Land, which has delivered 54 green community schoolyards.

Information about various types of green infrastructure and a map of ROW assets around the city are included at the end of this testimony.

As we have spoken about before, maintaining green infrastructure is critical; it can also be a challenge. We strive to keep our rain gardens healthy and performing by visiting rain gardens every 4-6 weeks. Rain gardens are designed so that water flows into them. If there is litter on the street, that water can bring litter into the garden. As you might imagine, high pedestrian traffic areas tend to accumulate litter in the rain gardens. We use a data driven approach to maintenance crew deployment and routing. Where our inspection data shows high-need areas, we send crews more frequently and where the data show less need, we deploy crews less frequently. We also supplement litter control with borough-based contractor support.

More time spent on litter control means less crew time available for other work like soil enhancement, tree pruning, plantings and horticultural services that are important for maintenance staff recruitment, job satisfaction, training and advancement.

Private Property

We cannot meet the city’s stormwater management needs with infrastructure only in public space. There must be stormwater management systems on private property, as well, so DEP provides financial incentives for installing green infrastructure on private property.

Through our capitally funded GI Grant Program, we’ve funded projects at 32 different sites – primarily building green roofs. To complement this program and fund even more green infrastructure on private lands, in 2021 we launched Resilient NYC Partners. This program offers an innovative pay for performance contract, to fund even larger projects on private lands with large amounts of site level impervious area. Property owners who have participated in our program include Green-Wood Cemetery, H+H Jacobi Medical Center, and Pratt Institute. DEP is currently working on a project at the Brooklyn Navy Yard and is coordinating with several new potential partners.

Stormwater Rule

The City alone cannot manage stormwater because most property in the city is privately owned. That makes the Unified Stormwater Rule one of our new most powerful tools for onsite stormwater management. Started in early 2022, it requires every site that disturbs 20,000 square feet or more of soil or adds 5,000 square feet or more of new impervious surfaces to maintain a certain amount of stormwater on their site.

They must submit a stormwater pollution prevention plan, or a SWPPP, which requires controls to be in place during construction to protect our sewers and waterbodies and the use of green infrastructure for runoff reduction strategies. As sites redevelop, they are performing better during wet weather than they were before development.

Since this rule was implemented, over 1,400 sites are meeting the new onsite stormwater management requirements, and an additional 200 sites have constructed or will soon be constructing green infrastructure to further reduce their stormwater runoff.

Examples of these projects can be found all over the city. One example includes 585 Union Street in Gowanus. This nine-story, 230,000-square-foot building will occupy the entire lot. Before the stormwater rule was in effect, a development like this likely would have just managed stormwater in an underground detention tank. With our rule, they are building a 6,000-square-foot green roof and a robust detention system. We even noticed them touting their green roof under building amenities on their website.

Daylighting

We also have our largest green infrastructure project to date nearing design completion, the Tibbetts Brook daylighting project. Tibbetts Brook originates in Yonkers and flows through Van Cortlandt Park in the Bronx before discharging into Hester and Piero’s Mill Pond. In the early 1900s the brook was diverted into an 8-foot-diameter tunnel that connects to a combined sewer flowing to Wards Island WRRF. Burying streams and creeks and merging them with sewers underground was a common strategy as our city developed, but a century later we are experiencing unforeseen consequences. Flowing a waterway into a combined sewer reaches that sewer’s capacity quickly. The Tibbetts Brook connection has led to significant issues over the years. Instead of building more infrastructure, like storage tanks, to try to hold a brook, we are going to daylight the brook — disconnecting it from the sewer and allowing it to flow more naturally.

Once completed, not only will this project reduce combined-sewer overflows to Harlem River by 220 million gallons a year, but it will allow for the creation of a new public greenway between Van Cortlandt Park and West 230rd Street and enhancing connectivity and access as part of the Empire State Trail.

Cloudburst Management Systems

A cloudburst is a sudden, heavy downpour in a short amount of time. Cloudbursts can overburden the sewer system and cause flooding. Cloudburst management systems capture stormwater until the sewers can handle the flow.

Cloudburst management projects often feature special community amenities and open spaces that can be used by the public on dry days. For example, the cloudburst project designed for NYCHA’s South Jamaica Houses is a sunken basketball court that will absorb and divert stormwater during future storms. Most days, the basketball court will provide recreation for residents. During cloudburst events, the stormwater will intentionally be diverted to the court, which will hold the water safely until the rain is over, taking that rainwater off the street and out of the sewers.

Cloudburst hubs are large scale cloudburst projects, generally designed for a multi-block area where directing, collecting, storing, and transferring stormwater can have a meaningful benefit on localized flood attenuation and the added benefit of CSO reduction. We use existing land and retrofit public spaces to allow for more enhanced stormwater management. These can be implemented more quickly than larger nature-based solutions that may rely on identification of vacant lands or property acquisition. These projects require close coordination with our colleagues at Parks, DOT, DOE, SCA, and NYCHA.

Stormwater Master Plan and 2024 Stormwater Analysis

DEP’s green and gray infrastructure teams are coordinating to develop a stormwater master plan for New York City that will lead to a more resilient system overall. This comprehensive stormwater master plan that will assess necessary upgrades, engineer amended drainage plans, and set funding priorities. This planning process will take years, but the result will be targeted approaches to capital investments, including nature-based solutions where it could help manage surface flooding and longer-term gray infrastructure upgrades.

In 2024, DEP released the 2024 Stormwater Analysis, which is the first building block for the master plan. This stormwater management update highlighted the City’s challenges with managing stormwater in a changing climate and examined stormwater challenges and solutions in four case study locations.

Of course, stormwater management cannot be done by DEP in a silo. Work will need to be coordinated among city agencies. Fundamental policy decisions will need to be made, in particular the acceptable levels of service and the level of acceptable flooding in our environment. DEP’s work will inform these decisions.

Financing (including BRIC grants)

Most of DEP’s work is paid for by water and sewer rates. We constantly think about how we balance our needs, the demands of New Yorkers for better services and especially floodwater protection, and the need to manage our water rates to be affordable.

DEP aggressively pursues outside funding for our work, and we have had strong successes receiving funding, including federal funding. In particular, our cloudburst projects have been receiving Building Resilient Infrastructure and Communities (BRIC) grants from FEMA. The federal government recently announced that FEMA is ending the BRIC program and canceling all BRIC applications from Federal Fiscal Years 2020 through 2023. We are still figuring out what impact this may have. We remain in close conversation with our city and state partners as it pertains to our federal funding streams and will work with these partners to try to mitigate and minimize impact as much as possible.

Legislation

Before I conclude, I will speak briefly about the two pieces of legislation being heard today. We have been discussing the bills with your staff, and look forward to continued discussions.

The first bill on today’s agenda is Int. 1253, which would require DEP to notify the local Council Member 30 days before installing a bioretention system in a right-of-way. We generally support this bill, but want to make some edits. The Department of Design and Construction (DDC) manages most of DEP’s GI projects. DEP and DDC both recognize the importance of speaking with the community and elected officials, and we have robust outreach plans already in place. We have spoken to DDC about this bill and are happy to supplement these outreach plans to fill any gaps. We would like to continue discussions with DDC and the Council to determine the best way to do that and to make some changes to the bill before it is passed.

The second bill is Int. 1254, which would require DEP to install 2,400 greened acres in MS4 areas by 2035. As we discussed with your staff last week, we are fully committed to expanding GI across the city, but we oppose the GI requirements in this bill.

As a quick background for those listening, MS4 stands for Municipal Separate Storm Sewer System. In this system, separate pipes carry wastewater and stormwater. In contrast, in combined sewer areas, wastewater and stormwater are carried by a single pipe. Approximately 60% of the city has combined sewers, and 40% are MS4 areas.

Our first concern is that we disagree with the use of greened acres as a metric. When our GI program began in 2012, there was a greened acre target, but we have since realized that greened acres are not a good metric, because the concept of greened acres does not fully capture what GI does. The greened acre metric has been removed from our CSO consent order with the state and replaced with reporting on the efficacy of our GI installations.

We continue to report greened acres in our NYC Green Infrastructure Annual Report for informational and comparative purposes, but we do use it as a metric for meeting our goals.

Another concern is that we do not know if GI is the best tool to address stormwater management and water quality needs in all MS4 areas. As I have described today, DEP has developed a suite of tools, because different tools are best suited for different goals and for different areas. Mandating a fixed amount could be counterproductive because it could require us to install GI where it is not going to be effective.

Finally, the bill’s mandate may not even be achievable. For the past 13 years, we have been installing GI across combined sewered areas. With our 16,000 assets, we have just reached 2,800 greened acres. The bill requires nearly the same amount of greened acres to be installed in MS4 areas over the next 10 years. There may simply not be enough space in MS4 areas. A minority of the city is MS4, and GI is not appropriate for much of the area. For example, we know that many areas with separate sewers in the city, like Southeast Queens, have high groundwater tables, which makes them ineligible for GI.

We share the Council’s goal of expanding stormwater management infrastructure through MS4 areas, and we appreciate the Council’s continued support of our efforts. We have already started installing GI in strategic MS4 areas, such as schoolyards and street medians, with partners like DOT, DOE, and Trust for Public Land.

As the Council is aware, it is important to remember that, while green infrastructure provides many community benefits, the goal of the program is not to simply green the city. These are engineered systems that are built to enhance the way the city manages stormwater, by reducing CSOs, improving water quality, and reducing flooding where possible.

Thank you again to the Council, especially to this committee and Chair Gennaro, for your continued support of nature-based solutions for stormwater management and other challenges. My colleagues and I are now happy to answer any questions that you have.

Examples of Green Infrastructure

Rain Gardens

Rain gardens resemble typical curbside tree beds but are engineered to capture and store up to 2,500 gallons of rainwater that then percolate into the ground, preventing flooding.

  

Infiltration Basins

Infiltration basins are designed to store and absorb rainwater into the ground below, but at sidewalk level they have a walkable surface that blends into the surrounding conditions.

  

Greened Medians / Stormwater Greenstreets

Greened medians, or Stormwater Greenstreets, are planted areas designed to collect and manage stormwater that runs off the streets and sidewalks. Unlike curbside rain gardens, these are typically constructed in the roadway, are usually larger than rain gardens, and have varying lengths, widths and soil depths based on the characteristics of the existing roadway.

  

Permeable Pavement

Permeable pavers and porous concrete allow water to seep in between the paving materials and be absorbed into the ground. DEP installs porous concrete in parking lanes in residential neighborhoods.

  

Green Roofs

Green roofs are made up of a top vegetative layer that grows in an engineered soil, which sits on top of a drainage layer. A green roof can be “intensive,” with thicker soils that support a wide variety of plants, or “extensive,” covered in only a light layer of soil and minimal vegetation.