Saving the Subway from Superstorm Sandy
I’m Klaus Jacob. My official title here at the Lamont-Doherty Earth Observatory of Columbia University is a special research scientist. I have been retired since 2001 and enjoy the activity freedom that this gives me, and I’m still running!
I’m a geophysicist, meaning I mostly focused on the solid Earth, and in particular on earthquakes, for about 35 years or so. I have been in this place since 1968. I actually came only one year for a postdoc, and it has been a long year, and a long postdoc!
Some people in the climate arena listened to a talk that I gave at the Earth Institute at Columbia University and they said, “You know, it would be very interesting if you could do the same kind of risk analysis, quantitatively, for climate events such as hurricanes, storms, flood events, rain events, and so on.”
I said, “I’m not sure I can do it, but I can try!” That was around 2000, and ever since, I have worked mostly with people from NASA GISS—the Goddard Institute for Space Studies—but also Columbia-affiliated people elsewhere, to really get a handle on what is at risk in New York City and the larger metropolitan area, not just the city itself.
What does all this earthquake stuff have to do with climate change and sea level rise? Well, we learned how to quantitatively make probabilistic forecasts with all the tools that seismology and earthquake engineering have in its toolkit. Those were never used in the flooding realm in the same sound, scientific way. FEMA hired some very down-to-earth consulting firms to do their hundred-year flood maps, but nobody really ever thought that a hundred year average occurrence—or the one-percent-per-year chance—is actually a reasonable, socially acceptable risk level at which you should either design, build, or insure.
It turns out in retrospect it was a big mistake, and this whole nation is still suffering from it. We have just seen it again a few days ago in Louisiana, where tens of thousands of people lost their homes, one hundred thousand people had to leave their homes. Of course, closer to home, in New York City, we saw the same during Sandy and in other places; we have seen it with Katrina in New Orleans, and you name it.
We didn’t know that Sandy would come, but we took a generic hundred-year storm and said, regardless of the meteorological details, “This is what we assume. What will happen?” And that was the question we asked.
In particular, it became very clear early on in our investigations what the impact of such a storm would be: that the Achilles’ heel of New York City is its infrastructure, and particularly the subway system is probably the most important one for the life of New York City to function—almost more important than power, water, and gas. Which sounds ridiculous, but to some extent it is simply true, because people need to get from where they live to where they work. And if that means is not available, the city won’t function.
So, knowing that, we really homed in on the subway system. We worked very closely with the Metropolitan Transit Authority, and particularly its subdivision known as the New York Transit Authority that runs the subway system and the bus lines. We got very detailed information about the geometry of the tunnels, their volume, all the access from the entrances, the shafts, the ventilation grids that you see on the sidewalk that underneath you can hear the subway rumble under your feet. But these openings are also the openings not just to air and people, they are the opening to the water when it’s on the street!
And so we got all the geometry together, made a three-dimensional model of the subway system, and let the water rise on the computer. And sure enough, to our big surprise, we found that those portions of the subway that are floodable at all would be flooded in about forty minutes. Four-Oh. Less than an hour. That means you’d better be prepared: having all the people out, having all the trains out, and maybe more.
That study was released in the summer or in the spring of 2011, which shortly thereafter was followed by a storm called Irene, and then by another storm called Lee. So when Sandy suddenly showed up on the weather radar screen, they said, “Oops, look, we have this study. How do we best prepare for it?” So they requested from the governor that they could shut down the subway system possibly as much as 48 hours before landfall, and then they sent their crews and engineers into the subway tunnels that were blue on our maps, meaning that they would flood.
They ripped out all the electrical control and signal systems. Why? Because if the salt water would get into those, they would have a huge problem. It would probably take three, four, five weeks before they would get the system back up. So to save those critical elements was absolutely essential. They took them up to the surface, the water came, they pumped out the water, they sucked out the mud, then took those signals and electrical control systems back; and after a week or ten days, depending on which line, the subway was running again.
That was absolutely phenomenal, but without us having done that very detailed study and really going with them for month after month after month when we did that study, sort of mentally through rehearsing what to do, this would not have happened.
Watch an interview with Klaus Jacob below.