When Flooding Becomes The New Normal

Why New York's 20th-Century Infrastructure Is Failing in a 21st-Century Climate

A few weeks ago, I was in Panama during the rainy season. Streets flooded daily, but people were wading through water like it was normal. Their infrastructure couldn’t keep up, but no one seemed surprised.

When I got back to New York, I didn’t expect to experience the same thing. But I did: water rushing into subway stations, streets turning to rivers, and a city trying not to get into a standstill. The difference? Panama doesn’t pretend it’s ready for this. New York still does.

We like to think of this city as invincible. But the truth is, New York City’s flooding is a problem and is the result of a collision between a 21st century climate and 20th century infrastructure. Flooding seems to have gone from rare to routine, and climate change is only making it worse. This isn’t just inconvenient, it’s dangerous. And the impact no longer just falls hardest on working class neighborhoods, basement renters, and essential workers. It is impacting everyone.

We can’t keep treating floods like flukes. We need serious investment in green infrastructure, updated sewers, and climate ready transit.

NYC subway flood (AI generated image)

Why New York City Floods

The city is grappling with a new climate reality, characterized by increasingly intense and frequent short-duration rainfall. This is straining and breaking a vast infrastructure network largely designed and built for the more predictable weather patterns of the previous century. Climate change is causing more frequent and intense rainfall, with storms delivering massive amounts of water in short, concentrated bursts. During Hurricane Ida in 2021, for example, Central Park was drenched with 3.15 inches of rain in a single hour.

This intensity is critical to recognize because the city's aging sewer system was only designed to handle about 1.75 inches of rain per hour.¹ When rainfall exceeds this capacity, the system is overwhelmed. Water has nowhere to go and erupts from drains, flooding streets, homes, and subways.

This issue is made worse by the city's landscape. About 72% of its surface is covered by impervious materials like asphalt and concrete, which prevent rain from soaking into the ground.² Instead, these surfaces act as funnels that channel huge volumes of runoff directly into the already strained sewer network, which guarantees that it becomes overburdened quickly during a downpour. This type of rainfall-driven event, known as pluvial flooding, can happen anywhere in the city, far from the coast.³

The Impact on Key Infrastructure

When the sewer system fails, the effects cascade across the city’s most critical infrastructure, with the subway system being particularly vulnerable. As a largely underground network, the subway's own drainage pumps are connected to the city's sewers. When the city system is full, it can no longer accept water from the subway, causing millions of gallons of stormwater to back up onto tracks and into stations. This paralyzes the transit network, trapping trains, causing widespread service suspensions, and resulting in tens of millions of dollars in damages. Even on a dry day, the MTA pumps 14 million gallons of groundwater out of the system, highlighting its constant battle with water.⁴

Above ground, the impact is just as severe. Major highways like the FDR Drive and Major Deegan Expressway frequently become impassable, shutting down critical arteries and causing city-wide gridlock. Flooding also leads to widespread property damage, with the most tragic consequences occurring in basement apartments. These units, often a source of affordable housing, can become deadly traps during flash floods, as seen during Hurricane Ida when 11 of the 13 fatalities in the city occurred in flooded basements.

What It Will Take to Fix This

Addressing New York City's flooding requires a multi-layered defense combining traditional engineering with innovative, nature-based solutions. The first layer involves massive investments in "grey infrastructure"—the pipes and tunnels that form the city's backbone.⁵ This includes upgrading and expanding sewers to increase their capacity, building large underground storage tanks to hold excess stormwater during a storm, and flood-proofing the subway system by raising stairwell entrances and installing deployable floodgates.

The second, and increasingly critical, layer is "green infrastructure." This strategy uses natural systems to absorb and manage rainwater where it falls, before it can overwhelm the sewers. Thousands of green infrastructure assets have been built, including curbside rain gardens (bioswales), permeable pavements that allow water to soak into the ground, and green roofs that absorb rainfall. Large-scale programs like the Staten Island Bluebelt preserve entire natural drainage corridors of streams and wetlands to manage runoff effectively and affordably. This hybrid approach is being implemented through "Cloudburst" projects, which strategically integrate green and gray solutions at a neighborhood level to handle intense, localized downpours.⁶

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The path forward for New York is clear. It requires moving beyond the cycle of shock and recovery and accepting that the sky overhead is now a formidable threat. The solutions require prioritizing. New York is strong but strength means being ready, not just resilient.

Investing in a hybrid defense of smarter grey infrastructure and widespread green, sponge-like surfaces is the only viable strategy. Ultimately, New York must build a city that doesn't just fight water, but makes room for it, creating a future where the rhythm of life isn't dictated by the forecast.

1. https://comptroller.nyc.gov/reports/is-new-york-city-ready-for-rain/

2. https://nychazardmitigation.com/documentation/hazard-profiles/flooding/

3. https://a816-dohbesp.nyc.gov/IndicatorPublic/data-stories/flooding-and-health/

4. https://www.mta.info/guides/weather-service-guide/storm-flood-hurricane-service

5. https://climate.cityofnewyork.us/initiatives/extreme-rainfall-adaptation/

6. https://www.nyc.gov/office-of-the-mayor/news/681-24/mayor-adams-next-generation-new-york-city-s-investments-flood-prevention-and#/0