Atop a 20 foot ladder inside a New York City subway tunnel on a recent week night, a worker plunged a drill with a bit as long as a sword deep into a wet wall. Pulverized stone showered onto the third rail below, before the worker plugged the fresh hole with a length of rubber hose.
Many of the now familiar tribulations of the city’s subway system are self-inflicted: Chronic delays and overcrowding are rooted in a history of mismanagement by officials and elected leaders who have long neglected repairs and updates to a century old system, where aging cars run on worn out tracks and are controlled by antiquated signals. Last year, Gov. Andrew M. Cuomo said that more than $800 million would be invested in a subway emergency plan to turnaround the beleaguered system.
While a significant portion of that plan is focused on the subway’s brittle infrastructure, money is also being used to help the system fight a force not entirely under its control: water, 13 million gallons of which is pumped out on a regular dry day, according to the Metropolitan Transportation Authority, which oversees the subway system.
Floods from broken water mains and natural disasters like Hurricane Sandy have periodically swamped the subway, but on a daily basis the subway is always wet: Bored through layers of Manhattan schist, Fordham gneiss and Inwood marble, the subway snakes through stopped-up natural springs and is surrounded by the groundwater that sloshes beneath the city.
As a result, water is a constant menace. Liquid dripping on electrified equipment can cause a short and wreak havoc — in January, water soaked an electrical signal box beneath midtown Manhattan, disrupting the Sixth Avenue subway line for more than a day.
“What happens when a hair dryer that is plugged into the wall falls into the bathtub?” said Joseph J. Lhota, chairman of the Transportation Authority. The system is built to withstand water — to a point, he said. “Getting it wet is one thing, having it sit in a puddle is another.”
The water under the city that constantly seeps into the subway has never been fully charted, but an 1865 map by the topographical engineer Egbert L. Viele shows the waterways of the once-green island of Manhattan. In one area, a stream courses along what is now 32nd Street, pooling in a small pond just west of Lexington Avenue, while a tributary of the East River becomes a block-wide river along East 106th Street in Manhattan. Both ripple near what would become the path of the 4, 5 and 6 lines.
In Brooklyn and Queens, a glacial aquifer permeates through beds of sandy Gardiners clay, the groundwater infused with metal-corroding salt from the ocean on one side and the brackish estuary of the East River on the other.
The MTA’s drainage system has the capacity to siphon off about 1.5 inches of rain per hour, according to transit officials, and is equipped with 289 sump pump rooms alongside the tracks that funnel excess water from leaks, rain or rapid snowmelt into the sewer system. But heavy rainfall can overwhelm the city’s sewer system and send water cascading into the subway, as occurred in 2007 when a storm crippled the system, delaying or disabling every single line.
The threat of rising waters as a result of climate change has added another layer of threat to the subway, which has prompted transit officials to identify ways to make the system more resilient. Among other measures, high-tech trap doors and vent covers have been installed over all of the 3,000 openings into the subway in low-lying areas south of 14th Street in Manhattan. The subway is also using a different type of concrete that is embedded with impermeable plastic membranes to replace older concrete in the system.
Keeping water at bay is also a key feature of the work that will be done on the Canarsie tunnel, which carries the L line between Manhattan and Brooklyn and was badly damaged in 2012 when 7 million gallons of salt water poured in during Hurricane Sandy. Next year, officials are planning to close the tunnel for renovations that will include the installation of Kevlar curtains and submarine doors that can seal off onrushing water.
Despite the constant challenge water has posed, the subway has not always done an effective job of reducing the system’s vulnerability. Before Hurricane Sandy, the Transportation Authority relied primarily on sandbags and plywood to defend the subway from flooding and did little proactively to make the system more waterproof. “We learned our lesson,” Lhota told the Times in an earlier interview.
Lhota, who as chairman of the Transportation Authority during Hurricane Sandy was credited for quickly restoring the subway, said he made an unpleasant discovery during the summer when he assumed leadership of the transit agency for a second time. Though the subway has tens of thousands of drains designed to collect water and help remove water from the system, they were not being properly cleaned. “I don’t know why,” Lhota said, adding that clearing the drains has been a focus of the emergency plan.
Grouting crews fan out across the subways every night, looking for runnels down walls and stalactites of muck oozing from ceilings, patching up incursions that are closest to electrical components first. Since the summer, more than 750 leaks have been plugged and more than 5,400 drain boxes have been cleaned along more than 100 miles of track. Crews have also cleaned more than 17,000 of the subway’s 40,000 grates.
Still, the battle is never ending, Gerard James, a structure maintainer for the Transportation Authority, said as he stood inside a tunnel one night, filling in leaks. “Sometimes you’ll plug a leak, and you’ll come the next day and it’s still leaking, and you have to come and grout again,” he said. “But the water has to be attended to.”This article originally appeared in The New York Times.