Climate scientists saw this coming, and their estimates on service restoration are no more encouraging.

Last fall, as part of a massive report on climate change in New York, a research team led by Klaus Jacob of Columbia University drafted a case study that estimated the effects of a 100-year storm on the city's transportation infrastructure. Considering MTA Chairman Joseph Lhota’s comments today that Hurricane Sandy's impact on the subway was "worse than the worst case scenario," it seems pretty safe to put Sandy in the 100-year category. In that case, assuming the rest of the report holds true, the subway system could be looking at a recovery time of several weeks, with residual effects lasting for months and years.

The researchers modeled a potential 100-year storm that consisted of either a category 1 or 2 hurricane hitting nearby, or a severe nor’easter that coincided with high tide. (As we know now, Sandy was a hybrid of all three events.) The models predicted complete flooding of several tunnels after such an event, including all the tunnels in the East River:

Based on their models, Jacob and colleagues wrote that a 100-year storm could leave roughly 1 billion gallons of water to be pumped from the city’s network of subway tunnels. (To give you an idea of scale, that’s equal to the average daily consumption of drinking water in the city.) If all 14 tunnels flooded, it would take about five days to pump each one clear, according to the report. However that’s the best-case scenario; a week per tunnel is more likely.

Immediate flood-clearing isn’t the only concern. As Ted Mann writes for the Wall Street Journal, salt water is likely to have considerable residual effects on the aging subway system. Jacob and colleagues write that equipment damaged by brackish water will at least require time to clean and could also require time for replacement. In some cases, when the parts are too old and no longer in production, it could require completely new infrastructure:

There probably are not enough personnel trained to rebuild and refurbish equipment simultaneously in multiple subway lines even if the equipment could be procured. There is some existing equipment that, if damaged, cannot be replaced because it is obsolete and is no longer manufactured, nor are there replacement parts for it. Such equipment would have to be redesigned and then installed — a process that can take a long time.

Just how long is the 100-year question. The researchers estimate that, after a storm of this magnitude, it could take the subway system about 21 days to get working at 90 percent functionality. If all potential damage is considered, Jacob and colleagues warn that timeline could increase to several months, and that "permanent restoration of the system to the full revenue service that was previously available could take more than two years."

To be sure, these are just predictions. The transit authority made as many mitigating, preparatory measures as it could to limit the extent of the damage. Then again, Sandy may well have been worse than a 100-year storm.

About the Author

Most Popular

  1. Perspective

    In a Pandemic, We're All 'Transit Dependent'

    Now more than ever, public transportation is not just about ridership. Buses, trains, and subways make urban civilization possible.

  2. Coronavirus

    The Post-Pandemic Urban Future Is Already Here

    The coronavirus crisis stands to dramatically reshape cities around the world. But the biggest revolutions in urban space may have begun before the pandemic.

  3. photo: San Francisco Municipal Transit Agency employees turn an empty cable car in San Francisco on March 4.
    Transportation

    As Coronavirus Quiets Streets, Some Cities Speed Road and Transit Fixes

    With cities in lockdown and workplaces closed, the big drop in traffic and transit riders allows road repair and construction projects to rush forward.

  4. A pedestrian wearing a protective face mask walks past a boarded up building in San Francisco, California, U.S., on Tuesday, March 24, 2020. Governors from coast to coast Friday told Americans not to leave home except for dire circumstances and ordered nonessential business to shut their doors.
    Equity

    The Geography of Coronavirus

    What do we know so far about the types of places that are more susceptible to the spread of Covid-19? In the U.S., density is just the beginning of the story.

  5. photo: South Korean soldiers attempt to disinfect the sidewalks of Seoul's Gagnam district in response to the spread of COVID-19.
    Coronavirus

    Pandemics Are Also an Urban Planning Problem

    Will COVID-19 change how cities are designed? Michele Acuto of the Connected Cities Lab talks about density, urbanization and pandemic preparation.  

×