Forming Resilient Communities

Individual properties are part of a larger system. Stormwater Resilient Districts connect property-level action across blocks and neighborhoods to build coordinated flood resilience.

The Stormwater Resilient District

New York faces increased stormwater flooding, sewer backup, and combined sewer overflow events due to more frequent and intense rainstorms that overwhelm the City’s aging sewer infrastructure. This can cause localized street flooding, sewer backups, and Combined Sewer Overflow (CSO).

While city residents are increasingly aware of flood threats, many underestimate their personal exposure, failing to recognize that water flow and upstream conditions can impact properties far from the runoff origin.

With the exception of sparsely distributed bio-swales in public right of way, current city-wide mitigation efforts focus mainly on reducing effects after water enters the system – not at the source.

However, approximately one-third of the city is privately owned rooftop space, an impervious surface where a significant amount of rain falls, it is a major source of stormwater runoff outside the City's direct control. Managing runoff from these private spaces is crucial for reducing pressure on the overwhelmed sewer system.

So how do we address stormwater runoff at the source?

The Stormwater Resilient District

A Stormwater Resilient District (SRD) is a neighborhood, or part of a neighborhood, defined by city sewer infrastructure that feeds a given combined sewer outfall — for example, Owls Head-007 — where strategic, distributed stormwater interventions have potential to combat local flooding, reduce combined sewer overflow, and in turn influence the way the larger sewershed manages extreme rain events.

The catchment area that feeds the Owls Head-007 combined sewer outfall stretches from the park to the canal. Here, the red lines trace the under-street city sewer infrastructure. The outfall itself empties into the canal at the end of 2nd Avenue. OH-007 is home to approximately 21,000 people and comprises more than 3,400 properties across 73 blocks.

Utilizing the Flood Form tool, the abstract concepts of CSO’s and runoff metrics can be translated by providing block-level exposure profiles in which residents can understand their flood exposure and providing tailored strategies to address it.

This map shows Compound flood exposure in the Owls Head-007 Resilient District by block: the darker the blue, the greater the exposure to flooding. Note how the average exposure increases moving downhill from the park towards the canal.

Not all the stormwater that feeds a flood-prone area falls directly within it. This view shows the larger contributing areas for two low points along 4th avenue, one in lavender and one in orange.

The SRD framework empowers neighbors to see how upstream solutions positively influence downstream areas. By building shared capacity, the district can develop a coordinated system of projects to significantly decrease stormwater runoff and reduce flood exposure across the entire area.

Infiltration potential in the Owls Head-007 Resilient District, by block: the darker the orange, the greater the potential i.e. the better-drained the soil and the stronger the case for at-the-source interventions.

Because the sites where targeted interventions have the greatest potential to make a difference are not necessarily the same as the sites that experience flooding most acutely, transforming a sub-sewershed area like Owls Head-007 into a Stormwater Resilient District calls on neighbors at opposite ends of the area to recognize their shared stake in the resilient future of our city — and to organize, block by block.

Blocks with high stormwater exposure, highlighted in blue, are impacted by stormwater flows that begin along the top of the hill at Prospect Park

To address stormwater flows throughout the resilient district, blocks with high infiltration potential, highlighted in dark red, are best positioned to handle stormwater on-site, reducing their own flood exposure and that of their downstream neighbors.

Organized neighbors are able to...

Build common cause, momentum, and a shared will to action
Identify and site appropriate, property-scale intervention strategies with the understanding that they may fall disproportionately in certain areas
Pursue bundled projects that maximize impact
Advocate collectively for public investment

For example, interventions on just 14 high-potential lots could divert up to 500K gallons of stormwater from the sewers annually

The collective implementation of bundled projects that disperse flood mitigation capacity at the sub-sewershed level has incredible potential to advance individual-, block-, and neighborhood-scale resilience in the face of a changing climate that affects all New Yorkers. If the ten Owls Head-007 blocks with the greatest potential maximized their infiltration capacity, they could divert nearly 15 million gallons per year from the city sewer.

15 Million

gallons of stormwater diverted from sewers annually

Find Your Sewershed

Your property shares a combined sewer with thousands of neighbors. Enter your address to see the sewershed you drain to and how flood exposure looks across it, or browse the areas below.

Brooklyn · 39 sewersheds

Manhattan · 64 sewersheds

Queens · 42 sewersheds

Bronx · 42 sewersheds

Staten Island · 11 sewersheds

THE RESILIENT FUTURE: A VISION FOR OWLS HEAD-007 AND BEYOND

The Stormwater Resilient District offers a viable — and scalable — pathway to reduce local flood exposure and pressure on city infrastructure, moving us towards net-zero combined sewer overflow.

Imagine a resilient future in which we can interact safely and freely with a clean canal!

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