Rotterdam, London, St. Petersburg, and Toyko all have storm surge barriers to protect low-lying areas from flooding. In the United States, Stamford, Connecticut; Providence, Rhode Island; and New Bedford, Massachusetts all have storm barriers. Should New York, which suffered significant flooding two years in a row from Hurricane Irene and Superstorm Sandy, follow their example? Many are now demanding that some sort of action be taken to prevent future large scale flooding.
A proposed series of surge barriers could protect sections of New York harbor from the sort of flooding encountered earlier this year. The largest movable barrier would be likely be across the Verrazano Narrows with other barriers at Hell Gate in the East River, Port Amboy, and at Rockaway Inlet. The barriers would not be cheap. Cost estimates range from between $10 and $30 billion. Nevertheless, a recent poll suggests that four out of five New Yorkers support the idea, as does New York State Governor Andrew Cuomo and head of the Metrolitan Transit Authority Joe Lhota.
Not everyone would be protected by these barriers. They would protect the sections of lower Manhattan, Brooklyn, and New Jersey that were so badly flooded in Superstorm Sandy, but would provide no protection for the hardest hit areas along coastal Long Island and the Jersey Shore. Indeed, some estimate that the barriers could increase the height of local surge waters outside the barriers by 20%. The protection provided to lower Manhattan, the Red Hook neighborhood of Brooklyn and Hoboken, New Jersey might only increase the damage to the Midland Beach neighborhood of Staten Island or the coastal communities of Long Island. Then again, short of building a high dike along the coast of Long Island and New Jersey, it is difficult to see how they can be protected. Given that the attraction of these communities is access to the ocean, it is unlikely that such protection would be approved in any case.
The larger question is how to assess the risk of flooding. Were the last two years of flooding an anomaly that will not be repeated in a century, or are these levels of flooding increasingly likely due to climate change? These are difficult questions to answer. Nevertheless, the concerns about New York’s vulnerability to storm surge are not new. Engineers have warned of the danger of storm surge in New York harbor since at least 2009.