The MTA’s Climate Change Dilemma: How Do You Plug a Million Holes?


On the corner of Franklin and Varick streets in Tribeca, kitty-corner from the Ghostbusters firehouse, sits a prototype of the main weapon in the MTA’s war against water.

It looks like a normal subway entrance, except the railing at the back of the entrance is a little fatter, and a barely noticeable metal lip runs around the edge of the stairwell opening. Contained within that fattened railing is a Flex-Gate, a rolled-up Kevlar mat developed by Delaware engineering firm ILC Dover. In the event of a major storm, MTA workers can unlock and unroll the gate, securing it against the metal lip to provide enough protection to keep out ten feet of water.

“In five minutes, a team can come out here and deploy a stairwell,” explained ILC Dover design engineer Ralph Elgesem as he oversaw the final installation of a Flex-Gate at a Canal Street entrance this spring. “No more than ten, depending on what other accessories they have to remove, such as handrails.” The Flex-Gate is based on self-inflating balloons that ILC Dover designed for space missions — if the MTA weathers the next storm surge successfully, it may be thanks to the same technology that helped land the Mars rover.

Only fourteen Flex-Gates have been installed to date — subway entrances aren’t standardized, so each entrance plug has to be individually designed. ILC Dover is under contract to eventually provide another nine, with more than forty additional locations still waiting for the MTA to bid them out.

It’s an exceedingly deliberate pace, considering that nearly four full years have passed in the city since the flooding that resulted from Superstorm Sandy, inundating much of the subway system beneath a thirteen-foot storm surge, and resulting in damage that is still awaiting repair. But the MTA proudly points to the Flex-Gate as a major improvement in response to Sandy. “Right now, today, both with our temporary measures as well as what we’re working on long term, we are far better prepared to address flooding than we were back in October of 2012,” says authority spokesperson Kevin Ortiz.

Better prepared doesn’t mean fully prepared, though. You could think of the subway as a giant drainage system — put enough water on the streets of New York, as Sandy did, and that’s exactly how it behaves. And it only takes one weak point for floodwaters to submerge subway tunnels. Just a few feet away from the Franklin Street entrance and its Flex-Gate sits a case in point: a ventilation grate that provides fresh air to the station underneath — and a clear path for water to pour down into the station.

In lower Manhattan alone, the subway system has over 5,600 such street openings that the MTA considers “vulnerable” access points for floodwaters. “It’s stairs, it’s vent bays, it’s hatches, it’s manholes, it’s duct entries, it’s elevators, it’s escalators,” says Ortiz. And to effectively protect the subways, every one of them has to be sealed in the day or two between a storm’s approach and its arrival.

Ortiz says the MTA is working on deployable vent covers that can be triggered by subway workers in advance of a storm. But they’re not even in the prototype stage, and asking workers to cover up 5,600 openings would leave a lot of opportunity for simple human error to let the water in.

Whether New York City’s subway system suffers another catastrophic flood depends on two things: The pace of the work now being done to protect the system, and when the next threat brewed up by a changing climate arrives. If Hurricane Hermine had zigged instead of zagged the first week of September, we could have seen a massive storm surge instead of a mere fall breeze.

At least one prominent climate expert thinks that the MTA’s piecemeal approach isn’t up to the task. “We are fiddling around on the edges, and have no plan for a sea level–rise resilient, sustainable transit system,” warns Klaus Jacob, a Columbia University scientist who’s co-authored several reports on the climate’s impact on the subways. He should know: It was Jacob who, just weeks before Sandy hit, warned the New York Times that a storm hitting at just the wrong time could submerge tunnels and leave them out of commission for weeks.

For the most part, Jacob notes, the billions of dollars that the state has spent so far on the subways as part of its “Fix and Fortify” initiative have gone toward repairing existing damage, not preventing future flooding. “These are all repairs post-Sandy,” says Jacob. “That does not really prepare the system for the next Sandy.”

And the next Sandy could come at any time.


When Superstorm Sandy made landfall in New York City in October 2012, several hundred million gallons of seawater poured into the city subway system. The salt water, as water will do, immediately headed downhill, and for a transit system that’s mostly underground, there was a lot of downhill to go: Within hours, stations all over the city were submerged, and the tunnels connecting Manhattan to Brooklyn and Queens were underground rivers.

It was a one-time catastrophic event that city subway riders are still paying the price for. Sandy repair work won’t be complete until sometime next decade, at a cost of at least $4.8 billion. The R train was disrupted for years; the G is still enduring service outages. All that is a mere prelude for the coming L-tastrophe, when, from January 2019 until mid 2020, no L trains will run between Brooklyn and Manhattan, leaving Williamsburg residents and weekend clubgoers alike left to piece together travel plans involving shuttle buses, ferries, and possibly a canoe or three. And looming in the distance are repairs to the 2/3 and F line tunnels under the East River, something that could take those trains out of weekend service for months at a time.

But while a Sandy-level storm surge was once believed to be a once-in-100-years event, climate change and rising sea levels mean that’s no longer true. A century ago, when the subways were new, sea levels were about a foot lower, according to Columbia University climatologist Radley Horton. “If storms don’t change at all, just by virtue of raising that baseline, we would turn the current 1-in-100-year flood event into something that happens roughly three times as often, maybe more,” Horton says. Storms will change, though: A warming atmosphere is expected to increase the energy available to power storms, increasing the likelihood of Category 3, 4, and 5 hurricanes; Sandy was barely a Category 1 when it made landfall.

Melting glaciers in Greenland and West Antarctica are predicted to raise sea levels two to six feet by the end of the century. That, combined with stronger storms, could mean even bigger problems than those caused by Sandy. According to MTA and city data crunched by Steven Romalewski, mapping service director for the Center for Urban Research, CUNY Graduate Center, at least thirty subway entrances sit at less than eleven feet above sea level — the point that Sandy’s maximum floodwaters reached. (Another seventy aboveground station entrances would see seawater lapping at their steps, including just about the entire Rockaways line.) Add another four feet of sea level rise, and several dozen more could be at risk, including such inland candidates as Broadway on the G and 110th Street on the 6.

“Sandy gave you the really big storm surge but not a lot of rain,” says Horton. “Not all storms have that profile. Imagine a case where there’s a storm that gave you the surge and heavy rain at the same time.”


Climatologists have been sounding the alarm about subway flooding for years. As far back as 2001, a study by Jacob and other Columbia scientists warned that sea level rise could triple the frequency of storm surges during the next century. In 2008, Jacob, Horton, and three other Columbia climatologists authored “MTA Adaptations to Climate Change: A Categorical Imperative,” a 48-page road map for preventing subway Armageddon. That was followed in 2011 by a study for the New York State Energy Research and Development Authority titled “Responding to Climate Change in New York State,” which warned of the need to seal ventilation grates and called for a new working group to plan flood resistance across all of the region’s transit systems.

Neither of those things happened. And the first wake-up call came in September 2011, when Hurricane Irene came inches from creating the flooding that the climatologists had warned about. It was thanks to the resulting scare, says Jacob, that in advance of Sandy the MTA sent workers into tunnels that the climate scientists had identified as a flood risk to hurriedly rip out electronic control and signal systems to keep them from being damaged by salt water. (“They should have gotten a lot of kudos for that,” says Jacob.)

Following Sandy, elected officials started acknowledging the dangers of climate change, and “resiliency” became a buzzword in city planning circles, even if many of the 2008 recommendations remain as yet unfulfilled. “It’s not that the MTA is sleeping,” says Jacob, who says authority engineers are ready to start tackling flooding problems the minute they’re made a funding priority. Rather, he says, “You should point more [of] a finger at the governor, the assembly, and the federal government, and say, ‘Help the MTA to do its job; they want to do it.’ ”

Evaluating how much the state is spending on shoring up the subways against future floods becomes tricky in a hurry. Most criticism of the MTA’s finances has focused on its $14 billion annual operating budget, which is funded largely via a mix of fare revenue ($5.9 billion), tolls ($1.8 billion), and state and city tax dollars ($5.5 billion). It’s a number that’s been stretched in recent years as ridership has soared, reaching 1.76 billion riders last year — up from 1.64 billion the year before Sandy.

Repairs and prevention, though, fall under the MTA capital budget, a rabbit hole that can baffle even veteran city economists. Approved every five years, the capital plan is, as its name indicates, more a goal than a commitment: Of the $35 billion in the 2010–14 capital plan, over $13 billion still hasn’t been bonded out. The newer 2015–19 plan, meanwhile, wasn’t approved until late last year following a public squabble between Mayor Bill de Blasio and Governor Andrew Cuomo over where the money would come from — and many of its funding sources remain undetermined.

Following Sandy,the Federal Transit Administration unleashed a torrent of cash — with the state and city required to kick in partial matching funds — which was immediately funneled into the capital budget. But most of the money spent so far has gone toward permanent fixes to replace the patchwork repairs put in place after the storm. Repairs to the Montague Street tunnel (the R line), the Greenpoint tube (G), and Steinway tunnel (7) are all either complete or will be soon; the reconstruction of the South Ferry station (submerged in more than eighty feet of water during Sandy, just three years after it opened), is expected to be complete by June of 2017, says Ortiz. And all these projects include “hardening” the tunnels against future flooding, which involves such measures as replacing century-old cable ducts with new waterproof ones.

As for future flood prevention, in 2013 the MTA allocated $5 billion in “mitigation” money (as distinct from “recovery”) to New York City Transit — i.e., the subways and buses — virtually all of it from those federal funds. How much has been spent, though, as opposed to allocated, is a different story. According to the MTA’s own capital program figures, about $250 million of that has been spent on new flood walls at several train yards, deployable vent covers, those Flex-Gates, and several other line items. Meanwhile, a whopping $4.6 billion sits in various “reserve” funds — some of which include items such as increasing bus rapid transit service to Staten Island ($589 million) that, while arguably useful, have little to do with protecting the current system against storm damage.

And even then, there’s no indication that anyone, at any level, has estimated how much spending it will take, and how soon it might be possible, to defend against an eventual Sandy 2.0. (Voice queries on this subject to Governor Cuomo’s office, as well as to the state assembly and senate transportation committee leaders, went unanswered.)

To truly make New York’s subways waterproof, says Jacob, the MTA would need to entirely rethink its ventilation system, which was a marvel of 19th-century engineering but leaves too many openings for water in the 21st century. Jacob’s preferred alternative would be a closed system, with exhaust fans drawing fresh air into the system, as is done for automobile tunnels — something that would almost certainly come with a price tag in the billions.

Instead, the state’s plan appears to be to plug along, fixing the low-hanging fruit, like blocking entrances and shoring up rail yards, and hope that the rest can hold until whenever the next storm arrives. “Just like we say the banks are too big to fail, the problem is too big to be addressed,” says Jacob. “But of course as we delay and procrastinate, the problem gets bigger and bigger.”