Flood Risk is Much Higher in Black Communities. Traffic-Calming Green Infrastructure Can Help.
More than 70% of New York City’s surface area is impermeable streets, sidewalks, parking lots, and rooftops. With the majority of space unable to absorb rainfall, water collects in low-lying areas such as curb cuts, subway stations, and basement apartments – restricting mobility, damaging infrastructure, and endangering lives. When heavy rain overwhelms New York City’s sewer system, impermeable surfaces deliver sewage and street pollution into waterways. Our stormwater infrastructure is already overburdened and many neighborhoods periodically flood, and yet New York City is projected to receive 10% more rain and one foot of sea level rise by the 2030s, which will further endanger our most vulnerable communities.
Spatial Equity Findings on Flooding* Analyzed By City Council District
Black New Yorkers are more impacted by flooding. In the 10 City Council districts with the most flooding, the number of Black residents is 32% higher than the average district.
Flooding will decimate communities in Southeast Queens. The two most flood-prone City Council districts, 32 and 31 along the waterfront in Southeast Queens, have 30% and 21% of their residents, respectively, living in projected stormwater and coastal floodplains.
The most flood-prone districts are some of the least prepared for it. The 10 City Council districts expected to see the most flooding have less water-absorbing greenery – with 10% less permeable surface area and 22% less tree canopy than the average district – despite 85% more of their residents living in a floodplain, compared to the average district.
Recommendations
Build “permeable corridors” on all New York City streets in the flood hazard zone (Zone V, A, and Shaded X) using water-absorbing green medians. Require all streets that can be outfitted with permeable surfacing to be retrofitted by 2026 to optimize storm wave and high tide drainage. Converting asphalt into planted medians can reduce runoff by 80% and also reduce pedestrian fatalities and injuries by 30%.
Daylight all “deep flood” intersections citywide with green infrastructure, such as bioswales, street trees, and rain gardens, to control rainwater flooding. The New York City Department of Transportation and Department of Environmental Planning should work together to create a plan to daylight all intersections subject to “deep and contiguous” flooding with flood control infrastructure. One bioswale can manage as much as 2,200 gallons of water during a storm.
*percent of residents living in stormwater and projected 2080 coastal floodplains
