NYC subways have a built-in tool for preventing floods. Where was it l

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After Hurricane Sandy devastated New York and flooded its subway system in 2012, the Metropolitan Transportation Authority (MTA) knew it wanted to behave. The storm prompted an estimated $5 billion in harm, largely from water getting in the place it shouldn’t have.

“Observe, rails, sign cables, escalators—each piece of apparatus that operates within the New York subway system was affected in a roundabout way,” says Robert Laga, deputy enterprise lead for the MTA’s Development and Improvement division.

Flooding after Hurricane Sandy in 2012 [Photo: Leonard Wiggins/MTA/Flickr]

With a altering local weather and excessive climate occasions on the rise, the sort of flooding is anticipated to turn out to be extra widespread. Preventing it from inundating the subway system has turn out to be a new precedence, and a novel flood prevention system now in place might be a part of ensuring Hurricane Sandy-level harm doesn’t happen once more.

Floodgates have been put in in 68 low-lying subway and PATH (Port Authority Trans-Hudson) stations in Decrease Manhattan. Housed on the road degree above the stairwells that lead down into the stations, the floodgates are made from a Kevlar-based material that may be rolled out horizontally forward of flood occasions to create a sort of lid over the openings.


[Photo: courtesy ILC Dover]

However the system will not be designed for each sort of flood menace, as deadly flooding throughout final week’s Hurricane Ida made evident.

The flooding from that occasion got here largely from the sheer quantity of rainwater that overwhelmed the stormwater system, with more than 3 inches falling in a single hour. Although Hurricane Sandy wasn’t as robust as Ida, the flooding was extra intense as a result of it overlapped with a excessive tide, inflicting a storm surge to circulate from the Atlantic into the subway tunnels and underground stations. Each occasions are uncommon, however the overlap of a storm and a lunar-influenced excessive tide is extra simply and reliably forecast. So when it involves preventing floods from taking down the subway system, the MTA is planning round future Sandys reasonably than future Idas.

[Photo: courtesy ILC Dover]

The system, the Flex-Gate Stairwell, was developed by ILC Dover, a Delaware-based firm identified for producing the spacesuits worn by NASA astronauts. By its connections with the Division of Homeland Safety, ILC Dover was contacted by the MTA after Hurricane Sandy. With federal flood safety funding in hand, the transportation company wished the devastation of 2012 to be a one-time prevalence.

[Photo: courtesy ILC Dover]

“They got here with a set of attention-grabbing necessities,” says Fran DiNuzzo, president and CEO of ILC Dover, noting that the best flood prevention system would be capable of maintain again 16 ft of water, be saved on-site, and be simply deployable and detachable. “So that they have been wanting for a unicorn,” DiNuzzo says.

[Image: courtesy ILC Dover]

“We primarily got here up with a system that I’ll loosely name a very high-tech window shade,” he provides. The Flex-Gate system includes a mixture of tarp-like sheets of coated Kevlar and a restraining net of Kevlar that may face up to hundreds of kilos of stress. With a easy crank, a employee can roll the gate out of its storage compartment alongside tracks on either side of the stairwell and latch it on the floor degree, turning the gaping gap of a subway entrance into a waterproof seal. In checks, the system has been capable of face up to 16 ft of water.

“It’s a vital funding within the subway system,” says Laga, including that the price to put in the programs at every station ranged from $600,000 to $750,000, including as much as greater than $40 million. He stresses that the system isn’t designed to stop harm from flash flooding, which is tougher to foretell and quicker to inundate the system in comparison with a tidal surge. By monitoring forecasts and tides, Laga says, MTA officers can determine inside hours whether or not the Flex-Gate system ought to be activated. Although there have been a few shut calls, Laga says the system has but to be deployed.

Although the MTA is prepared for the following storm surge, the flash flooding of final week’s Hurricane Ida underscores the problem going through transit businesses like these in New York and Zhengzhou, China, the place 12 individuals died just lately when heavy rainfall flooded subway tunnels. Some excessive climate occasions could be predicted and deliberate for, however others can catch individuals and infrastructure programs by lethal shock.


The brand new Flex-Gate programs are a recognition that cities have to do extra to stop such devastation, however the MTA’s Laga concedes that defending the subway system is a shifting goal. “Once they constructed the subway system years in the past, there was no such factor as international warming or sea degree rise,” he says. “Now there’s.”