Why the New York Subway Keeps Flooding — and What to Do About It

Why the New York Subway Keeps Flooding — and What to Do About It
Photo: David Dee Delgado, Getty Images

The New York metro area turned into a lake on Wednesday night following a 1-in-200-year-plus rainstorm from Hurricane Ida’s remnants. The streets were flooded, but underground was even worse.

The New York subway system filled with water as pumps faltered amidst the onslaught of rain. Videos posted to social media showed shocking scenes of stairways turning into rivers, gushing geysers of water, and tracks inundated with floodwaters. At one point, service was suspended on every one of the system’s 26 lines and partial and full suspensions remain in effect for more than a dozen lines as of late Thursday morning. Mayor Bill DeBlasio declared a state of emergency and warned residents to “stay off the subways.”

It’s the most striking example since Hurricane Sandy of how a transit system and a city designed for last century’s climate is unprepared for that of a new century, one where heavy rain will only become more common and intense due to the climate crisis. The subway is the heart and arteries of New York, and letting it succumb to increasingly frequent floods is simply not an option. But as this summer has shown, there’s a lot of work to be done.

“What we saw last night is a clear sign that we need to continue investing in resilient infrastructure and that every dollar is critical to making that happen: federal, state, and local — and the need to identify funding sources such as congestion pricing,” Lisa Daglian, the executive director Permanent Citizens Advisory Committee to the Metropolitan Transportation Authority, said in an email.

This has been a summer of intense rain in New York, and Wednesday was unfortunately not the first time the subway system has been inundated. Hurricane Henri and a no-name rainstorm in July also overwhelmed the system, but Tropical Depression Ida took things to another level.

“The number of subway lines that were closed down is definitely the highest that I have seen since Sandy,” Klaus Jacob, a geophysicist at Columbia’s Earth Institute, said.

Jacob sounded the warning of the threat of sea level rise to the subway well before the 2012 superstorm formed and wrought havoc in the city. With Sandy, the damage was largely driven by storm surge that, with a boost from sea level rise, overtopped subway defences. Wednesday’s issue, though, was too much water from the sky rather than the sea. Both are issues that are expected to get worse due to climate change: 1-in-100-year rainstorms will become increasingly routine across North America in the coming decades while the odds of storms like Sandy will also rise.

“It is apparent that more resiliency investments beyond Superstorm Sandy expenditures are desperately needed due to the frequency of these storms,” Daglian said.

The MTA already pumps an astounding 13 million gallons of water out of the subway system a day as part of a constant war against groundwater and the Atlantic. In the wake of Sandy, which sent corrosive saltwater into the tunnels, ruining ancient electrical infrastructure in the process, the city allocated $US7.7 ($10) billion toward fixing the train lines and making them more resilient. In addition, it launched a climate adaptation task force to evaluate the severity of coming threats and create plans to prepare.

In 2018 — six years after Sandy inundated subways, damaging more than 3,219 kilometres of tracks — officials began installing drainage systems beneath some stations and walled off a railyard in Coney Island to shield it from floodwaters. That following year, authorities began testing a “flexgate” which seals off the entrance to the subway stations when floods hit and can hold back up to 4 metres of water. To do so, they intentionally flooded some train stations, freaking some New Yorkers out.

But an analysis released last month by the Regional Plan Association found that 20% of the subway system’s entrances are at risk during a 1-in-100-year rainfall event. Wednesday night’s was a 1-in-500-year one. In a televised interview on Good Day New York on Thursday morning, the MTA’s CEO and acting chairman Janno Lieber also said other resilience plans are in the works.

“We’re going to expand the resiliency efforts to look at these higher ground areas, higher elevation areas, in tandem with the City of New York which operates the street level drainage and sewer system,” he said. “We have to attack that now in this era of climate change.”

Preparing subways for the climate crisis costs money. A lot of money. Some funding could come from the $US1 ($1.5) trillion infrastructure bill that members of Congress are still battling over, which allocates $US66 ($89) billion for railways, with a pledge to use the money to “meet the intercity passenger rail needs of the United States” rather than achieving “a performance level sufficient to justify expending public money.”

But the cost of preparing the New York subway system alone for more floods from both rain and surge is a multi-billion-dollar project on its own. (The Long Island Railroad and Metro North are commuter lines that also require major upgrades given their routes through flood-prone areas.)

“Neither the MTA nor the city are designated for any funding for that sort of stuff,” Jacob said of the bipartisan infrastructure bill.

The reconciliation package, with its $US3.5 ($5) trillion in spending, could offer a more thorough fix. But New York’s subway is also hardly the only system that needs major climate upgrades either, and there’s trillions in fixes needed for other essential infrastructure across the country.

The subway system is also only one piece of the puzzle. Part of what made Ida’s rain so destructive is the endless concrete of New York’s roads, buildings, and footpaths that trapped the water, and the sewer system that was unable to handle the rainfall rates. Preparing the subway without addressing the infrastructure that ensconces it would be akin to trying to build a house without a frame. (With some parts of the city potentially facing ​​up to 9.5 feet of sea level rise by the end of the century — which in combination with rainfall could render some areas unliveable — some experts also say the city must consider not only preparing, but also relocating, infrastructure including subways).

Thaddeus Pawlowski, the managing director for Columbia’s Centre for Resilient Cities and Landscape, said in an email that one of the key protections for the subway would be “stopping the water before it gets there, or at least slowing it down. Reducing paved surfaces, planting trees, daylighting underground streams, creating more parks and green roofs” are among those solutions.

That points to the need for city, state, and federal governments to cooperate. The MTA is funded by the state while the city has its own departments to deal with roads and green space. While the city and state both have climate plans and visions, the process of syncing them up is, to put it politely, challenging.

“Ideally, [addressing flooding] would need the cooperation between those two entities,” Jacob said. “And each one has problems of their own. If you ask them to cooperate, it almost becomes a nightmare.”

A lack of data on how much the city has done with its climate plan also makes it hard to track just how much progress has been made versus what needs to be done.

“The relatively small amount of resiliency funding in the MTA’s capital plan (compared to investments made after Superstorm Sandy), coupled with the uncertainty around the city’s stormwater resiliency commitments to transit, raises important questions,” the Regional Planning Association analysis from last month said. “The responsibility for mitigating the impact of rain-induced flooding on transit seems to be falling into a technocratic gap.”

More transparency and cooperation, though, are vital to ensure that the city’s subway continues to function. (To say nothing of other essential infrastructure vulnerable to the climate crisis.) Other measures, such as adding green space, can also help lessen flooding aboveground and improve the quality of life for residents. And, as the RPA analysis noted, “Runoff water … does not care about political boundaries or agency jurisdictions.”