BY TERESE LOEB KREUZER | For the last three years, Robert Trentlyon, a public member of Community Board 4 (CB4) and the former publisher of Downtown Express, has been a man with a mission. He has been preoccupied with the implications of a sea level rise for New York City’s 520 miles of coastline and the possibility of a disastrous storm surge that could wreck large parts of the city and cost billions to clean up.
On January 5, Trentlyon spoke about the city’s vulnerability to the Community Board 1 (CB1) Planning and Community Infrastructure Committee, hoping that the committee would join CB2 and CB4 in framing a resolution asking the Army Corps of Engineers to study preventive measures against disaster.
“We’re in a lot of trouble here,” Trentlyon told the committee. “As we know, the sea level is going to be going higher and the storms are going to get more severe.”
Trentlyon noted that the city’s present mitigation policy is to create a “soft edge” of marshes on the circumference in order to lessen the effects of flooding.
“This makes a lot of sense if you’re living on Long Island,” Trentlyon said. “If you’re living in Manhattan, which is really hard edge, with giant buildings that go to the waterfront, what you really need are sea barriers.”
Trentlyon readily admits that he is not an expert on climate change, sea level rise or storm surge technology, but he consulted engineers and oceanographers who have studied these matters for years and who recommend storm surge barriers as the most effective means of defense. A storm surge barrier is essentially a wall with a gate that remains open unless it is needed to deflect a rush of water.
“Storm surge barriers are not a new concept,” Trentlyon said, and added that in the United States, a monster hurricane in 1938 that passed over Long Island on its way to New England, killing more than 700 people and leaving a swath of destruction, was the wake-up call.
“In 1938 after the hurricane hit, three cities — New Bedford, Providence and Stamford — all built storm surge barriers,” Trentlyon said. “The problem is that by the time they built them, 30 years had passed. London has them. Rotterdam has them. Venice is building them.”
Trentlyon said that two of the experts he had spoken to — Douglas Hill, a consulting engineer and an adjunct lecturer at Stony Brook University’s School of Marine and Atmospheric Sciences and Malcolm J. Bowman, a distinguished professor of oceanography at the University’s School of Marine & Atmospheric Sciences — recommended two alternative placements for storm surge barriers to protect New York City.
One idea would be to have three barriers: at the Narrows, a tidal strait separating Staten Island and Brooklyn, below the Throgs Neck Bridge, and at the Arthur Kill strait at the far end of Staten Island. Another proposal would be to have a single storm surge barrier between Rockaway and Sandy Hook.
“That’s a long distance,” Trentlyon said, “but most of the water level there is fairly shallow at about 20 feet. The Ambrose Channel — the main shipping channel — is in the middle of it.”
Either way, Trentlyon said that the estimated cost for the barriers would be around $10 billion, with half the money going to feasibility studies and design and half allocated to construction.
Trentlyon’s presentation was initially met with skepticism. “What do we know already about the risk?” asked Jeff Galloway, chairman of the Planning committee. “New Orleans, Rotterdam, Venice — all those places are under sea level already. That was the problem with New Orleans. Once you’ve breached the levees, you’re in a disaster zone. We’re not below sea level. We’re above sea level, though people like me who live in Battery Park City are very close to sea level. But I see the $5 billion price tag in the study, which probably translates into $10 billion before it’s actually built.”
Trentlyon replied that if New York City experienced a Category 3 hurricane, the estimated loss would be $200 billion between property damage and loss of time going to work.
“I would imagine a good chunk of that would be wind damage,” said Galloway.
“Part of it would be wind damage,” Trentlyon replied, “but if you have a 20-foot-high storm coming ashore, a lot of damage would be [from water]. Another study, which came out in August of 2011, was done by the Federal Transit Administration (FTA). They say a 20-foot storm surge would go into the subway system and except where the subways were elevated, the entire system would be covered with at least four feet [of water] within 40 minutes. You’re talking about salt water coming in. That means that everything’s damaged. All the machinery would have to be taken apart and cleaned. The estimate by the Federal Transit Administration is that that would take three-to-four weeks and, some engineers say, three-to-four months.”
Committee member Ro Sheffe wanted to know where Trentlyon got his data. “I was a meteorologist for the U.S. Navy,” Sheffe said, “and I’m curious about the source for this climatology information. First of all, has there ever been a 20-foot storm surge here? There have been records kept in New York City for 148 years.”
“I believe it was in 1821 the East River and the Hudson River rose up and they covered the entire island from Canal Street south,” replied Trentlyon. “In 1893, a Category 1 hurricane destroyed Hog Island, a resort island off the Rockaways in southern Queens. The storm hit. The island disappeared. It never came back. In 1938, a hurricane hit here. It was called the Long Island Express. It came up through Brooklyn and Queens and demolished a lot of the frame houses.”
While this conversation was proceeding, Galloway was reading the FTA study. “It’s talking about an eight-foot storm surge,” he said. “It says at that level, the subways would be flooded, and they estimated $58 billion in damage from just the flooding of the subways alone from an eight-foot storm surge at the current sea level height. And if sea levels rise, it’s going to go up to $84 billion so, based on this study, a relatively modest storm surge could have catastrophic consequences.”
In the end, the committee was convinced that something had to be done. It passed a resolution asking the Army Corps of Engineers to “expeditiously conduct a study about the feasibility of installing storm surge barriers to protect New York City.” It also asked that elected officials at the city, state and federal levels support such a study. The resolution was scheduled to go in front of CB 1’s full board on January 24.
Trentlyon’s mission is far from finished — but at least he was able to go home that night knowing that a few more people had come to grips with the perils on New York’s horizon.
