Oct
27

Gleaning lessons from Sandy’s floodwaters

By

This barrier at 148th Street protected the subway from what could have been catastrophic flooding throughout Manhattan. Photo: MTA New York City Transit / Leonard Wiggins

A year ago, New York City had no idea what was coming its way. As officials were scrambling and MTA crews hard at work reinforcing the system in advance of a storm called Sandy, We were waiting to hear if the subways would shut down, but the decision had seemingly already been made. By 7 p.m. on the 28th, no trains were running, and New Yorkers huddled in their homes to see just what Sandy would bring.

For the subway riders of New York, Sandy’s impact was immediate. We saw dramatic images of water-logged tunnels and video of the New York Harbor rushing into the stations in Lower Manhattan. It took the better part of a week for subway service to return to something approximating normalcy as the MTA had to combat flood waters and a major Con Ed power failure, and today, the R train is out of service for another year as the corrosive salt water essentially destroyed the infrastructure.

We still don’t know what the future holds for the other subway tubes that were flooded by Sandy. The Montague St. Tunnel took the worst of it, but the L train didn’t escape unscathed. In total nine subway tunnels flooded to some degree, and while the impact of saltwater depends upon the time of exposure, any contact between electrical equipment and the ocean will reduce the useful life of those components.

In this weekend’s New York Times Magazine section, as part of the paper’s look back at Sandy, Robert Sullivan went inside the subway system to tell the story of what happened before, during and immediate after Sandy. The piece is titled “Could New York City Subways Survive Another Hurricane?” and while Sullivan doesn’t offer up a clear-cut answer, it seems that the system is better equipped to withstand a storm even as resiliency efforts will continue for a few years.

Overall, I’d urge you to read through Sullivan’s piece. It talks of an agency dedicated to improving its response to storms while recognizing that it can’t seal off access points and call it a day. That — the knowledge and human creativity that came out of Sandy — is what will protect the subways when there’s another storm heading our way. There are some interesting stories and key takeaways. So let’s jump in.

On the interconnectedness of the subway system and why protecting 148th St. mattered:

[The plywood wall] endured, with about three inches to spare. The triumph might seem like a small one in the face of Sandy’s destruction, but it wasn’t. Here’s what it prevented from happening: After flooding the No. 3 line tracks to the south, and destroying millions of dollars worth of equipment, the Harlem River would have continued south, following Lenox Avenue to about 142nd Street, a junction where the 3 line joins the 2 line, which runs to and from the Bronx. By consulting both the Slosh maps and its own topographical maps, the transit authority determined the water would have flowed toward the Bronx, via what’s called the Harlem River-Lenox tunnel, and then east to 149th Street on the Grand Concourse. Then, in the worst case, the water would have moved through a connecting track, and like liquid moving through a Krazy Straw, the Harlem River would have flowed south through another under-river crossing, the Harlem River-Jerome tunnel, to 125th Street in Manhattan. From there, it would have flooded the downhill Lexington Avenue line — which happens to be the busiest one in the city, carrying more people every day, 1.8 million of them, than any other American subway system — to about 103rd Street, where the tracks rise, up toward Carnegie Hill.

On the speed and power of the floodwaters:

Inside the control center, the TV told them the surge had arrived. “All of a sudden the phones start lighting up, and you don’t have enough hands, you don’t have enough ears,” Mazzella says. “It’s nuts, the 6-Wire” — the internal communications line, which connects to the Police and Fire Departments — “starts going off, and you’re hearing that there are explosions down at the Con Ed plant, that there’s water cascading into the system here. . . .” The boards began to come back to life, the sensors in the tunnels registering the water as moving trains. New York City Transit had estimated that flooding would close a few of the 14 tunnels that go under the city’s waterways (called “tubes”), but at this time it looked as if nine of them would be lost.

On how pumps inside the Joralemon St. tunnel outperformed those near East Broadway:

It was the sound of old-school subway technology, a pneumatic pump powered by pressurized air from pipes that run all the way back up to 149th Street, where a compressed-air station was unaffected by Con Edison’s power outage downtown. There are dozens of air-compressor pumps all along the Lexington Avenue line; each one of them removes about 200 gallons of water per minute and is about 60 years old, having replaced early-20th-century models. Jezycki refers to these pumps as his Studebakers. They were struggling, but succeeding enough to keep the tunnel clear, draining the water that chased out Joe Leader before flowing downhill toward the East River tube. Aboveground, the plywood had kept the water out of the air vents.

There’s a lot more to take in — including one person questioning how the MTA spent $500 million on a station at South Ferry that didn’t have some flood protections — but I think these are the key points. It’s exceedingly difficult to protect the subways because of the redundancies and connections and because of Manhattan’s geography. It sounds as though only a few inches separated the city from a true public transit disaster that would have wiped out even larger chunks of the subway system.

Another Sandy will head our way at some point. It won’t be tomorrow but it may be next year, in five years or in 15 years. We won’t know until then if we’ve learned our lessons, and the subways will be forever vulnerable simple because they are the lowest point. For now, though, they’re back, and that, by itself, was a very impressive feat.



Categories : Superstorm Sandy

29 Responses to “Gleaning lessons from Sandy’s floodwaters”

  1. Spiderpig says:

    Are there any pictures of that “wall” in action with water up against it?

  2. Nyland8 says:

    Whenever stories of Frankenstorm Sandy are raised, I can’t help being reminded that, while it did arrive about high tide, it was still just barely a Category 1 storm, relatively dry in the northeast quadrant, with winds around 75mph. It seems that whatever lessons might have been learned, the future preparations are unlikely to protect against a much wetter Category 3 or 4 storm, of much longer duration.

    Entrances and vents in tidal flood zones 1&2 can’t, and won’t, be protected by sandbags and plywood. If the East River tubes are to be kept from flooding in a really large event, these are locations that must truly be hardened against a storm surge with flood gates, inflatables plugs, etc. When one looks at the bill for a “pound of cure”, it should be easy to get federal monies to take the “ounce of prevention” route.

    • Larry Littlefield says:

      Unless a hurricane goes “backward” — east to west — like Sandy, it will either have to hit NYC after going overland in New Jersey and weakening, like Irene, or will end up hitting farther east.

      This was pretty close to a worse case scenario.

      But not for the transit system. As bad as the damage in the tunnels was, things would have been far worse if the floodwaters had flowed the other way — toward the interlockings. That could have wrecked the system for years.

      • Nyland8 says:

        Well … no, Larry. There is nothing “backward” about an Atlantic hurricane traveling westward or northwestward. It happens quite often. In fact, it is how most of them are spawned … off the coast of Africa.

        The landfalls of dozens of hurricanes that have slammed the east coasts of Florida, Georgia and the Carolinas over the centuries have been well recorded. We’ve had them here too – though not as often.

        Sandy was a weird hybrid storm which managed to make landfall just as another system was arriving from the west. Among the results was that is was far dryer in the northeast quadrant than would ordinarily be expected from a hurricane. Up in Harlem we barely had any rain at all, even though trees were blown down.

        The point is that general flooding might have been much, much worse if the city had gotten rainfall amounts typical with a system that size. And with rising sea levels – which we have – and with rising ocean temperatures – which we also have – the likelihood of this “worse case scenario” repeating itself becomes increasingly probable.

        Imagine the tide at the NY/NJ Bight if the wind speed were twice as high. Couple that with a foot or more of rain over a four hour period, and suddenly Sandy becomes nothing more than a warning.

        We should heed it.

        • Larry Littlefield says:

          “There is nothing “backward” about an Atlantic hurricane traveling westward or northwestward. It happens quite often. In fact, it is how most of them are spawned … off the coast of Africa.”

          I didn’t make this up. I heard it from a professional meteorologist who is a transit buff and is on the radio. We corresponded about it years ago online, in a discussion of the possibility of the Coney Island Yard getting flooded and wiping out a third of the subway fleet.

          He said it was possible but a 10,000 to one shot for the reasons I noted. In fact,he said that given NYC’s many bearing wall pocket beam buildings, he would be more worried about the consequences of a weak earthquake — another low odds thing that could also happen here.

          • Michael_G says:

            Speaking of seismic risk, doesn’t the Upper Manhattan fault line travel right under the IRT viaduct at 125th & Broadway? I’ve always wondered if that ancient structure, among other sections of elevated transit infrastructure, could sustain relatively mild earthquakes, like the magnitude ~5.0 quakes that hit NYC in 1737 and 1884, or something stronger, like a magnitude 6.0-6.5, out on the Ramapo Fault in New Jersey.

            Has the MTA ever assessed seismic risk to its infrastructure? I suppose the chance of NYC getting hit by a catastrophic quake is considerably less than the uncomfortably more real risk of a mega-tsunami from a Canary Islands landslide that would wipe out much of the East Coast. At least NYC would have a few hours to take action in that nightmare scenario.

    • anon_coward says:

      irene the year before was a Cat 2 when it hit NYC and did very little damage. irene did more damage as a tropical storm in westchester than in NYC

      the last Cat 3 to hit NYC was 1938. before that NYC would get hit by a cat 3 every 70 years

    • Bolwerk says:

      The category is the strength of the sustained winds. Sandy was still a historically large and powerful storm.

      • lawhawk says:

        Sandy was a classified later as a post-tropical cyclone, where the power for the storm was due to temperature gradients, and not by tropical waters, which is how most cyclones (hurricanes) generate their power.

        Where Sandy differs from the hurricane tracks of many other storms is that it made the left hook instead of veering out to sea in a NE direction, which generally corresponds to the Gulf Stream/Jet Stream tracking.

        Sandy’s damage was due largely to a very large wind shield (over 1,000 miles wide) and the ability to move vast amounts of water against the coast coming in at astronomical high tides. There wasn’t as much rain associated with Sandy as with tropical storms like Irene or Floyd – both of which lingered for longer times over New Jersey, training heavy bands of rain for prolonged periods.

        And if Sandy struck an hour or two later, the storm surge in Lower Manhattan and other coastal areas would have been even more dire. Sometimes, it’s a game of inches, and that was the case here.

        • MichaelB says:

          This should be underlined. To say ‘it was just a category 1’ is to wholly misunderstand the storm. The size of the wind shield was the largest ever recorded in the Atlantic, and it set quite a few records for low pressure. When the storm surge is the primary source of damage (as opposed to wind) these things not only matter, they matter a lot more than category.

          That’s not to say a more serious storm isn’t possible, of course it is. But Sandy was huge and record breaking, and would have been even if it stayed out to sea and didn’t cause any problems on land at all.

  3. John-2 says:

    It does sound as though — for the Lex, at least — that the worst case scenario early in the Times article of the line being flooded from Harlem River inflow from Lennox Terminal is negated somewhat later in the article by the pneumatic pump story, and the fact the pumps apparently run along the Lex all the way to Mott Haven. It might have still survived Sandy, even if the Seventh Avenue IRT was hammered.

    You also really have to give either William Barclay Parsons and/or whoever came up with the idea for the pumps credit, if they were done originally as part of Contract 1, Contract 2 or the Dual Contracts Lex work during World War I. The fact that the oldest East River subway tunnel and the one seemingly (along with Montague) in the biggest line of fire from Sandy ended up with the least amount of damage, due to technology that dates back over a century, while nobody thought to put a pump or drain in the four-year-old South Ferry station that was placed below all the tunnels is ironic (and doesn’t reflect all that well on the MTA’s modern-day station planners when it comes to dealing with flooding).

    • D. Graham says:

      The point missed though is those very same pumps barely got by handling the Joralemon Street tube job. Add flooding from 149th/GC all the way down to 103rd and Lex and we have a very different outcome downtown.

    • David Brown says:

      John-2, sad to say, in a bureaucratic system people overlook things (the MTA back in the days forgot to add an Uptown Transfer at Broadway-Lafayette to the (6) and how much did that cost?). But pointing fingers accomplishes nothing. The questions are as follows? 1: Can the MTA get the Tunnels fixed and waterproofed (to the best of their ability before the next Storm)? 2: When will another Storm happen, and will it be closer to “Irene” or “Sandy” 3: How much will it cost? The one thing that we do know is this: Despite “Sandy”, FEMA Maps, and higher insurance rates, New York City will NOT stop NEW building on the water (I mean NEW not Rebuilding). We see the proposals for Waterfront Development for Empire Stores/Staten Island Wheel, Two Trees/Domino Sugar Plant Development, 77 Commercial Avenue and Greenpoint Landing up for votes at the City Council before the end of the year (Empire Stores/Staten Island Wheel is Wednesday). All of these areas were right in Sandy’s path. Now should we build in those spots? That can been debated, but it is what it is. If the City isn’t stopping, it means the MTA needs to keep right on building for the future (that does mean SAS down to Hanover Street, and Metro-North Expansion to The Bronx), and praying for the best, but planning for the worst. I think despite everything, they will.

      • Spendmore Wastemore says:

        “But pointing fingers accomplishes nothing.”

        Pointing fingers can do much good if the finger is pointed at the hack/buddy/apparatchik who weaseled into a job they were not capable of doing. Such as the NJ transit chief who figured that the fun thing to do when a large storm surge does a direct hit at high tide on your system is to park fancy new trains next to the water. In a place name “Meadowlands”… not “Highlands”. Was he trying to site NJT transit car condos? He should have been walked off the site by security, with his stuff boxed up and sent parcel post.

        The thing with spending other people’s money is you get into the not-my-fault business; the goal is to preserve the network that gets you elected, and having uncounted money to throw around works greatly in your favor. Doing it right the first time and paying only for actual work is hopelessly naive and will be punished; the 100s of millions going to NJT and the new South Ferry re-do, money to dig a hole and fill it in again, represents time, talent and materials not available to build something that works.

    • lawhawk says:

      That discounts the fact that the South Ferry site was swamped and overwhelmed by New York Harbor and that the Con Ed substation that powers Lower Manhattan below 14th Street went offline after it too was flooded.

      It takes power to keep the pumps running, and the uptown power generating facilities were not knocked offline by Sandy. That meant that the pumps could run continuously through the storm. The same couldn’t be said of the pumps that ran all through the system in Lower Manhattan.

      Going forward, building in redundancies for pump power backups and better shielding against storms will reduce the chances of losing the tubes again.

      • John-2 says:

        True, but why did the IRT think to put in pneumatic instead of wholly electrical pumps, when the other lines built later apparently went with fully electrical ones that were more subject to the 14th Street Con Ed plant going down (and was there a deliberate decision made a century ago to tie the pneumatic pumps into a power station away from the worst flood zones, or was that simply a lucky break on where the IRT decided to tie in the pumps to the power system?)

        Joralemon being in seemingly the worst possible place for a tunnel during Sandy and surviving better than any of the other East River tunnels is definitely something the MTA has to factor in when they do their post-Sandy strengthening efforts. The pumps didn’t keep the water out, and wouldn’t in a future storm, but rigging up similar second lines of defense pumps for other East River tunnels just in case the new storm barrier efforts aren’t 100 percent effective — even if it involves 100-year-old technology — isn’t a bad idea.

        • David Brown says:

          I live South of 14th Street, so I know exactly what you are talking about. I really expect that going forward that the backup systems will be in place. One of the very reasons why Mike Bloomberg stressed the importance of finishing Water Tunnel #3, was in case of an emergency, water will not get cut off, and going forward they can do the necessary repairs on Tunnels 1 & 2 ( those Tunnels have not been inspected ( let alone repaired) since they were opened). In addition the owners of 50 West st ( by the World Trade Center), actually changed the design of the building and moved the power supplies to a higher ground. There will have to be a price paid for it ( like higher water bills for the Tunnel), but it is worth it.

        • Nathanael says:

          “True, but why did the IRT think to put in pneumatic instead of wholly electrical pumps, when the other lines built later apparently went with fully electrical ones”

          Probably because the electrical grid was still in its infancy in 1904. Frankly, I don’t think it was forethought.

    • Spendmore Wastemore says:

      “….nded up with the least amount of damage, due to technology that dates back over a century, while nobody thought to put a pump or drain in the four-year-old South Ferry station…”

      This is the difference between PC cash burns and old Yankee thinking.
      The old timers spent their own money building things to work, unless their was a quick buck to make and a shyster to take it. Otherwise they built battleships, PCC cars and stuff that worked. It’s not to hard to think “hm.. Underground water pumps sitting below sea level. Gotta make’m so they work when they get wet”.

      The new way is to spend Federal dollars, which are free. Even better if the stuff suffers a “disaster”, in which case vast amounts of money pour in, to be spent even faster with more overtime and plenty of crevices to swallow $100K here, there, and everywhere. Heck, the MBTA in Boston had a predictable flood and cleaned up. How predictable? The original builder of the Green Line tunnel in the Fenway installed flood doors. When the flood eventually arrived, MBTA left the doors open, then helped themselves to a Federal bailout.

      Build stuff that works? You must be new in town. Now you get back to work and pay some o that tax!

      • Nathanael says:

        “unless there was a quick buck to make and a shyster to take it”

        Which, unfortunately, described most of the 19th century — don’t underestimate how much shystering there was.

        • Spendmore Wastemore says:

          True. I remember looking up the word “shoddy” and finding the story of Civil War troops being supplied with uniforms that disintegrated when wet. Not a small matter in a war.

          But, in terms of engineering, the late 19th & 1st 1/2 of 20th century had the will to build durable things with the inferior tools and materials of that time. Wasn’t there a critical mechanical switch machine that lasted around 100 years on the LIRR, replaced by a computer driven system which lasted less than 5 years? The newer, better one died with its first lightning hit, something which must have happened dozens of times in that spot over the years.

          We have greater ability now but it seems we don’t have the will.

      • Nathanael says:

        BTW, “the *Fen*way” in the “Back Bay” is an area you really can expect to have flooded. Just look at the names; it’s all fill.

        • Spendmore Wastemore says:

          Completely true, I remember bicycling through it. Olmstead, who laid out the park, included extensive gravity-driven flood control, with the addition of locks in the Charles River. Flooding was predicted when the landfill based area was created; Olmstead included natural-appearing marshy areas and other means to contain it, which worked for 100 years.

          The only thing he couldn’t plan for was Boston’s sedimentary layers of corruption since Curly.

  4. BoerumHillScott says:

    Building next to the water is fine, if it is done correctly – keeping key systems (or the entire building) elevated and taking other steps to protect the ground floor.
    In general, new buildings on the water survived fine while older ones farther in did not.

  5. Chris C says:

    I read the article over the weekend and was wondering if you were going to post about it.

    The only criticism I had about it was the lack of any maps that would have help those not overly familiar with how the tunnels link up appreciate how so much worse the damage could have been.

    The workers of the MTA deserve a lot of credit for what they did to (a) prevent far worse damage and (b) get the system up and running so quickly afterwards.

  6. Beebo says:

    I’m going to be very interested to see what happened to London’s system during this “St Jude” storm that passed through yesterday/today. I gathered they had to shut down several of the Tube lines. Wonder if they got as close to the precipice as the MTA was with Sandy.

  7. Michael Sherrell says:

    There are a few points that I just have make:

    a) The IRT subway when it was built had their own electric generating facilities in Harlem, and it other parts of the city! Over time the subways gained their power from Con Edison. The IND subways always derived their power from Con Edison. So when talking about the locations of pumping equipment, and their power sources, that is a fact to keep in mind.

    b) Plenty of people have made statements about the newer South Ferry station being flooded, while the older South Ferry station was returned to service after a major amount of refurbishment work. Too many people just seem to forget a few facts.

    One – BOTH OF THE SOUTH FERRY STATIONS WERE FLOODED WITH WATER – There are plenty of pictures that showd the damage to both stations.

    Two – water seeks the lowest level, and since the newer station is much lower in the ground than the older station, water that drained from the upper South Ferry station filled the lower one. It had really nothing to do with building construction methods or snide comments about “new stuff versus old stuff”.

    Three – note that both the lower South Ferry, and the lower Whitehall Street station and tunnel were flooded full of water. If the newer South Ferry station had not been built, the flood waters entering the older South Ferry station would have sought out other paths including the #4 and #5 Joralemon tunnel to/from Brooklyn as a place to flood.

    Four – The 14th Street Con Edison plant did have backup systems, some were however located within the same building, so as one system overloaded, the others became overloaded. There is fantastic footage of the storm nights, and the explosions that went on at the plant that left a third of Manhattan dark.

    Five – Yes, indeed major amounts of credit has to go to the MTA workers and staff for their efforts at mitigating the damage that Hurricane Sandy did to our transit system, for keeping loss of life at an all low, and for shepherding the recovery as they did. It is easy to point fingers a year later at what could have, should have, would have, and why didn’t you – all in all – things really could have been so much worse.

    Just my thoughts.
    Mike

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