New York City Is Not Built for This
The city is seeing rainfall patterns that look more like Miami’s or even Singapore’s, an official said at The Atlantic Festival.
New York City’s sewer system is built for the rain of the past—when a notable storm might have meant 1.75 inches of water an hour. It wasn’t built to handle the rainfall from Hurricane Irene, Hurricane Sandy, or, more recently, Hurricane Ida—which dumped 3.15 inches an hour on Central Park. And it wasn’t built to handle the kind of extreme rainfall that is becoming routine: The city flooded last December, last April, and last July—an unusual seasonal span. “We now have in New York something much more like a tropical-rainfall pattern,” Rohit Aggarwala, New York City’s environmental-protection commissioner, said yesterday at The Atlantic Festival. “And it happens over and over again.”
It happened today. Less than 24 hours after Aggarwala’s statements, rain arrived in New York City—the kind that sends waterfalls through Brooklyn subway ceilings, dangerously floods basements, and floats cars on the road like rubber ducks. Mayor Eric Adams said earlier today that the city could receive up to eight inches of rain today; parts of Brooklyn saw a month’s worth of rain in just three hours. New York State Governor Kathy Hochul has declared a state of emergency, and New York City residents received emergency alerts cautioning them to avoid travel (unless, ominously, they were evacuating), seek high ground, and avoid driving.
“You always build to the record” when designing infrastructure, Aggarwala said yesterday. The problem comes when the changing climate creates conditions that blow through those records. He also said the 1.75-inches-an-hour standard isn’t met across the board. “That’s our target—not everywhere in the city is up to that standard.” And since Hurricane Ida hit two years ago, there have been at least half a dozen instances in which certain neighborhoods have received two inches or more of rainfall an hour, he said. “That’s not a pattern New York City is accustomed to. That’s a pattern that Miami might be accustomed to, maybe Singapore.”
Already, today’s rainfall, as measured in Central Park, is the worst the city has seen since Ida, Zachary Iscol, the New York City emergency-management commissioner, confirmed at a press conference today. (Ultimately, Ida dropped 7.2 inches of rain on Central Park and nearly six inches on Prospect Park.) The city’s sewers simply can’t process water that quickly. “The sad reality is that our climate is changing faster than our infrastructure can respond,” Aggarwala said at the same conference.
Extreme rainfall isn’t just a New York City problem. A recent analysis found that one in nine residents in the contiguous United States is at significant risk of storms that will bring at least 50 percent more water than their local infrastructure can handle—overwhelming the pipes, channels, and culverts that might have met the rainfall records of the past. Any place trying to fix this mismatch might not have the basic information it needs, either: The periodic update of national rainfall from the National Oceanic and Atmospheric Administration, for instance, won’t arrive for another three to four years, which could keep climate-resilience efforts lagging behind the speed at which the climate is changing.
As acute and random as these events can feel, Aggarwala warned yesterday against myopia. “We can’t say, ‘Well, this is a one-off and maybe it won’t happen again,’” he said. “This is our new reality.”