New York City is surrounded by water, with over 130 neighborhoods situated along 520 miles of coastline. Its populace of 8.3 million residents—the largest metro area in the United States—relies heavily on its vast transportation system. And as sea levels continue to rise, the future of both the city and its transportation network are in jeopardy.
Coney Island is an ideal place to view this present-day peril. Start on a dead-end stretch of Shore Parkway. The road here floods with even a light rain, covering the broken concrete in thick mud. On one side of the street is Coney Island Creek, where Hurricane Sandy’s surge pushed ashore and inundated this Brooklyn neighborhood in 2012.
Coney Island Yard Complex, one of the largest rapid transit train yards in the world, sits on the other side. This 74-acre facility was flooded with 27 million gallons of seawater during the hurricane, leaving the train yard crippled.
“Coinciding with the high tide, the storm washed in water and debris which quickly inundated the tracks, switches, motors and signal equipment. In Sandy’s wake, the yard more closely resembled a lake than a storage area for subway trains,” New York’s Metropolitan Transportation Authority (MTA) wrote in a 2013 synopsis. “The storm left the track-switching operation at the world’s largest rapid transit maintenance and storage facility unable to be controlled remotely.”
Since 2018, the MTA has been working on a project to protect the Coney Island Yard from future storms and sea level rise. The authority built 21,000 feet of new drainage, nine flood gates, two pumping stations and a 4,280-foot-long bridge above the yard, elevating third-rail power lines and communications cables out of the flood zone. They are also erecting a 12,000-foot-long floodwall around the perimeter of the yard.
This enormous flood barrier is not yet finished, but several pieces can be seen along the muddy edge of Shore Parkway. It is a brutal, utilitarian piece of work, made of metal sheets driven 30 feet underground that then stretch 8 to 14 feet toward the sky. The wall currently ends at a porous metal fence lined with burst sandbags, providing a stark reminder of what previously protected the yard.
Similar rebuilding and mitigation efforts are taking place around the city. When Hurricane Sandy overwhelmed New York City, it damaged almost every part of the transit system. Boats were pushed onto train tracks, tunnels and subway stations flooded, and bus depots and train yards were filled with corrosive saltwater. During the storm, some of the MTA’s flood barriers were little more than plywood and piles of sandbags.
Once complete, these upgrades are intended to protect the yard and the five boroughs from future cyclones and torrential downpours—calamities whose rains, surges, and winds are being boosted by the climate crisis. For those who have assessed the threat of sea level rise in New York City, even this may not be enough.
One Enormous Challenge, Many Little Fixes
After Superstorm Sandy, the MTA committed $7.7 billion toward rebuilding and making its system more resilient. It also created a Climate Adaptation Task Force to evaluate the threats facing the transportation system and recommend solutions. One of its first tasks was to determine what level of flooding to actually plan for.
“For the Metropolitan Transportation Authority (MTA), climate change is not only an urgent reality, it is a reality to which all six MTA agencies are already devoting extensive financial, planning, and engineering resources,” the task force wrote in its 2017 report. “There is no responsible alternative,”
Four of the MTA’s six branches adopted different Design Flood Elevations, but the water rise they anticipate is sobering.
MTA Bridges and Tunnels, which operates seven bridges and two tunnels in New York City, is preparing for a 500-year storm akin to Hurricane Harvey. The Long Island Rail Road and Metro-North Railroad systems manage 1,381 miles of tracks and 247 train stations. They are preparing for flooding four feet above FEMA’s Advisory Base Flood Elevations (ABFE). And New York City Transit, the regulators of all subways and buses, is designing for three feet above a Category 2 hurricane.
“The challenges that come from climate change are much greater today than they were when many of the MTA’s features were designed and created,” Projjal Dutta, the task force chair and the MTA’s Director of Sustainability Initiatives, told Gothamist/WNYC in a recent interview. The task force is currently tracking a dozen projects. “Our interventions are rarely of a grand scale. They are not storm surge barriers. But, they are small, they are numerous.”
The finished projects include waterproofing Staten Island’s St. George Terminal with a new drainage system, floodwalls, and water-resistant plastic track ties. The authority built a seawall along the Harlem River at the 207th Street Yard and installed thousands of smaller barriers across Manhattan, including flood doors and flex barriers at subway entrances.
“A lot of the flooding happened through these very small things that you would not think of as grand at all. But when there is 10 or 11 feet of standing water above these openings, that can amount to a lot,” said Dutta. “In Lower Manhattan alone, there are approximately 500 of them, from manhole covers to where the grates equalize the air pressure.”
Mission accomplished…for now
In March, the MTA marked a major milestone in its rebuilding efforts, completing repairs and upgrades on the last of its 11 tunnels that Sandy damaged. Inside the Rutgers Tube, where the F line travels underneath the East River, they replaced 4,635 feet of subway track, repaired 250 feet of tunnel wall and installed hundreds of thousands of feet of signal and communications cables.
“We are nearing the completion of all the Sandy-related resilience work,” Janno Lieber, the President of MTA Construction & Development, recently told Gothamist/WNYC. “This is huge stuff. I mean the whole system, we needed to move the controls out of the flood zone. We’ve needed to harden a ton of infrastructure to keep water out. We’ve needed to increase pumping capacity in 11 tunnels that were deluged.”
Ultimately, the MTA’s investment will only protect the transit system for a limited period of time. In its March 2019 report, the New York City Panel on Climate Change projected that the city is facing between 1.25 and 9.5 feet of sea level rise by the end of the century. This will permanently flood some neighborhoods, augmenting tidal flooding and storm surges along the way. According to one of the report’s authors, a large-scale managed retreat from the waterfront seems inevitable.
“It will be a city at higher elevations,” said Dr. Klaus Jacob, a geophysicist at Columbia University’s Earth Institute, who served on the city’s climate panel from 2008 to 2019. He anticipates that residents in dozens of coastal neighborhoods will need to relocate to higher ground as sea levels rise.
“This will cost at least in the hundreds of billions as a project because it’s not just the housing,” Jacob added. “If you move around hundreds of thousands of people, it will [mean] changes for school capacity, for medical facilities, parks, libraries, you name it. The whole infrastructure of the city will have to adapt to this migration.”
A managed retreat of this scale would influence the MTA’s infrastructure, especially its coastal train routes, which would have to be moved inland, according to Jacob. This would be extremely difficult, given the density of the region’s buildings and other infrastructure.
“Many of them are at such low lying places,” said Jacob. “The only opportunity I see, if we want to modernize and stabilize our train connections in the Atlantic coastal areas, is to go to elevated tracks.”
Jacob has worked on several assessments of how sea level rise will impact the MTA, including a pre-Sandy evaluation that predicted some of the storm damage. In a more recent analysis, he and a team of Columbia engineering graduate students evaluated how the MTA’s new network of approximately 4,000 flood measures in Manhattan would fare during another Sandy.
“It was amazing how much the leakage rate or the flooding of the subway had gone down. It was essentially eliminated,” said Jacob. “That would get you way beyond the year 2050 and maybe even later, depending on the rate of sea level rise.”
But that is if the system performs precisely as designed. The team tested what would happen if certain singular failures occur. They found that if just one barrier at a subway entrance were to fail, it would be almost like the other 3,999 odd barriers weren’t there.
“There’s no redundancy in the system,” said Jacob, who recommended that the MTA create an entirely new set of backups for its Manhattan flood protection. “It’s the famous weakest link in the chain.”
With many pieces of its infrastructure at or below sea level, the MTA is painfully aware of the threats posed by the climate crisis. The Metro-North’s Hudson line is located at the edge of the Hudson River. The A train barely skims above Jamaica Bay. Elevating or relocating train lines and moving facilities to higher ground may eventually become necessary, but the MTA is saving those decisions for a later date.
“Right now, we are not retreating, we are battening down the hatches and making sure that all of our systems can manage the risk that has been created by climate change,” said Lieber from MTA Construction & Development. “We learned a lot from the Sandy experience. No part of the city was hit harder than the MTA, so we are trying to put all those lessons into effect. So, I am going to leave [it] to wiser heads, the question of retreat.”
Columbia University’s Earth Institute will convene a conference this June to investigate the question At What Point Managed Retreat? It is a conundrum facing cities around the world. For Jacob, the answer is clear.
“Why don’t we start to plan for that now. That means our land use and zoning will have to be updated now,” said Jacob. “New York City better adapt. Because if it’s not adapting, it’s doomed.”
Full disclosure: Nathan Kensinger will be an unpaid panelist at the Columbia University academic conference on managed retreat mentioned in this article.