Tempest-Tossed, Let’s Not Imitate New Orleans

[This opinion piece was published online in the New York Times Room for Debate series on 11/1/12 as part of the debate Should New York Build Sea Gates?  Someone also published an editorial with a similar point to my second paragraph in the Sunday Review this morning, though with detailed consideration of the issue’s morality.]

QUESTION FROM THE TIMES:

In September, The Times reported that New York City might be “moving too slowly to address the potential for flooding that could paralyze transportation, cripple the low-lying financial district and temporarily drive hundreds of thousands of people from their homes.”

This week, the theory was tested, as Hurricane Sandy flooded parts of all five boroughs. Could sea gates or storm barriers help to prevent future flooding in New York City? Are they cost effective? Or is there a better alternative?

RESPONSE

Tempest-Tossed, Let’s Not Imitate New Orleans

Hurricane Sandy has taken a severe toll on New York City, but it’s not likely to be repeated soon – it was an unlucky merger of the city’s worst storm surge since 1821 and a full-moon high tide.  While we should continue to study storm surge barrier options, we should avoid rushing back in time to the dam-building fanaticism of the 1930s-1950s, when rapid common sense actions are available to improve our floodwater resilience.

The original proposal to build three barriers and protect NY Harbor inside Verrazano Narrows does not protect the 300,000 people in Brooklyn and Queens that live around Jamaica Bay within the floodplain of a Category 2-3 hurricane (below 16 feet above sea level).  Worse yet, experiments with our storm surge model show that these barriers would slightly worsen the flood elevations in Jamaica Bay.  So, this plan may be perceived as choosing “winners and losers”, and the area with the greater population (and votes) is in the latter group.

Another barrier proposal is protective of nearly the entire city, but features massive levees over Rockaway Peninsula and other low-lying nearby land areas.  Who really believes that New Yorkers will be interested in taking the “New Orleans approach” to stopping storm surges?

Also, every barrier plan that has been presented would reduce exchanges of our city’s estuarine waters with the ocean, degrading water quality and changing temperature and salinity.  This would have complex effects on our rebounding ecosystems and coastal fisheries, a source of pride for a growing number of New Yorkers.

The silver lining is that now we’ll finally have the political will to tackle all the sensible, efficient defense measures we’ve been neglecting.  A great deal of protection can come from simply making better small-scale and (this time) watertight adaptations to protect subways and electrical infrastructure, such as retractable subway stairwell domes or rubber subway air vent covers.  Let’s leverage the amazing designers and engineers of New York City and have open design competitions.  This could be a 1-year or 2-year process, and we could dramatically improve our resilience in the rare event that seawater comes into our city.

And beyond that, we will now have license to think big.  Large areas like Jamaica Bay and Lower NY Bay have lost wetlands, oyster reefs and other natural systems that could be brought back to enhance our defenses.  These ecosystems can slow and reduce a storm surge, and they would have a wealth of other benefits including absorbing carbon dioxide from the atmosphere.  We can simultaneously work to improve our flood resilience, coastal ecosystems and climate, instead of rushing to pour concrete on the problem.

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4 Responses to Tempest-Tossed, Let’s Not Imitate New Orleans

  1. Read it in the Times :-) :-)

  2. markbahner says:

    Hi,

    I think a portable storm surge protection system should be designed, which would be capable of protecting any city on the East Coast or Gulf Coast with a few days notice.

    Only a portable system would be capable of protecting barrier islands like Long Island. And only a portable system could protect not only New York, but Norfolk, Savannah, Miami, Tampa, Mobile, etc.

    Imagine a tube, 20 feet in diameter (the size of a house) filled with seawater, floating in the sea. Now imagine another tube inside that tube, maybe 5-10 feet in diamter, filled with air. So the air-filled tube floats above the water, like a beach ball. But the air-filled tube can’t go anywhere, because it’s inside the water-filled tube.

    Imagine that these tubes extend tens of miles, parallel to the shore, but several miles out to see. When the hurricane comes from way out at sea towards the shore, the water stacks up behind the air-filled tubes. Some flows over it, but not much. The air-filled tubes get pushed towards shore, but because they’re inside the water-filled tubes, the tubes move very slowly (say 1 mile per hour). In contrast, the hurricane is moving towards shore more rapidly, say 10 miles per hour. So eventually, the eye of the hurricane passes over the tubes. As long as this happens before the tubes get pushes completely to shore, the water behind the tubes just flows back out to sea, and the storm surge is minimal.

    This is just a conceptual design. The more important aspect is that it’s *portable* system. Not fixed. That way, it can be custom-deployed to exactly match every storm.

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