Protecting New York City from the Next Big Storm
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SPECIAL REPORT / afTer The supersTOrm But for new pipes, Ghandehari suggests a much lower-tech solution: Protecting New York City put utility lines in tunnels that human workers can walk through. from the next big storm “The rule of thumb is that you need to have access for inspection,” he says. “Cities of the future should consider AS THE full extent of the devastation A team led by Malcolm Bowman how to deal with providing access to wreaked by superstorm Sandy sinks of Stony Brook University’s Storm the urban lifeline.” in, the question for the future is how to Surge Research Group has studied the In the meantime, New York has some protect the New York metropolitan area protection that could be offered by a difficult decisions ahead as it recovers when a similar disaster strikes again. system of three flood barriers (see map, from Sandy. “The hard thing is going to Embryonic plans exist, both to erect right). To the south of Manhattan, these be where to rebuild, and where not to massive flood barriers and for “soft” would be built across the Verrazano rebuild,” Barone says. engineering schemes that would Narrows, between Brooklyn and Staten It might be best to leave some redesign waterfronts to incorporate Island, and the Arthur Kill, between neighbourhoods uninhabited so that wetlands, oyster beds and other natural Staten Island and New Jersey. To the they can take the brunt of future floods. features that could slow storm surges. north-east, another barrier would block “We had built on barrier islands,” Barone The hope is that Sandy will provide the rising waters in Long Island Sound says. “Where an entire neighbourhood will – so far lacking – to turn these plans from surging down the East River. has been destroyed, do you rebuild it? into reality. “It’s not just a wake-up call, Simulations using a “juiced up” Or do you do something else?” it’s a wake-up scream,” says Cynthia version of hurricane Floyd, which hit It’s a cruel calculus, but for the Rosenzweig of Columbia University. the region in 1999, indicate that the shoreline just north of New York Years of work and tough decisions barriers would protect large areas City that was hit by hurricane Irene lie ahead. Flood defences don’t come from flood waters, says Brian Colle, last year, Sandy’s aftermath is all cheap and in a region with more than a member of the Stony Brook team. too familiar. 2400 kilometres of coastline that is Though Sandy’s surge was much “In two years, most parts of the home to 20 million people, it isn’t bigger, in principle barriers could be region have been touched by natural No trains today: possible to protect everything. For engineered to hold back such floods. disaster,” Barone says. “We can’t assume South Ferry instance, little can be done to shield the The big problem with these barriers, this will be every 10 or 20 or 50 years subway station low-lying beachfronts on Long Island however, is that they would leave any more, like we used to. We are going in Manhattan’s and Jersey Shore, which Sandy ravaged. densely populated areas – especially to have another one.” n financial district There’s also a philosophical gulf parts of Brooklyn and Queens – at the Additional reporting by Michael Marshall was inundated to be bridged between civil engineers, mercy of a storm surging into Jamaica who want to hold back the waves with Bay. In fact, those districts would be hit concrete and steel, and those who even harder if these barriers were built. favour more natural solutions. Philip Orton of the Stevens Institute of REUTERS One thing is clear: the threat is Technology in Hoboken, New Jersey, only going to get worse. Sandy’s storm studied what would have happened if surge peaked at about 3.5 metres above the three barriers were in place when average sea level in lower Manhattan. tropical storm Irene hit in 2011. His New York City officials currently simulations showed that they would assume that a 2.6-metre flood will have diverted the water, increasing happen once a century, and a 3.3-metre flood levels by 5 per cent in Jamaica Bay. flood once every 500 years. The New Any solution that protects York City Panel on Climate Change, co- Manhattan at the expense of poorer chaired by Rosenzweig, has estimated neighbourhoods is likely to be that, by 2100, rising sea levels could unacceptable – especially after the bring 100-year floods every 25 years residents of Sandy-devastated Staten (Climatic Change, doi.org/fdq5g8). Island complained of being the Factor in changes to storm patterns “forgotten borough” as the city focused expected with climate change and on restoring normality to Manhattan. they could strike every three to 20 years So the preferred plan is to keep the (Nature Climate Change, doi.org/jnm). northern barrier, and replace the two Barriers with gates that can be southern ones with a much larger, closed when a surge is brewing are the single barrier across the entrance obvious solution. It’s a tried and tested to the New York-New Jersey harbour, technology, used extensively in the with gates to allow ships through. Netherlands to protect low-lying areas Preliminary estimates from from North Sea storms. engineering firm Halcrow suggest that 8 | NewScientist | 10 November 2012 121110_N_SR_p6_9_Corrosion.indd 8 6/11/12 17:56:30 For daily news stories, visit newscientist.com/news Flood barrier future Manhattan, for instance, would fringe its familiar skyscrapers with salt Preliminary plans exist to erect barriers to protect the New York metropolitan area marsh, and extend the island’s from hurricane-induced oods, with some oering more protection than others southern tip into a field of rectangular islands. Streets would get porous Long surfaces and some would be equipped Island with subterranean channels that would Sound drain storm surge water back out to sea. The designs are stunning but do not come with cost estimates or storm- surge modelling to show what they might achieve. “I see them as dream exercises,” says Benjamin Orlove of Columbia University, who studies LaGuardia environmental decision-making. Plan 1 Airport EAST RIVER Does not stop ooding While wetlands can obstruct a storm MANHATTAN BARRIER around Jamaica Bay QUEENS “Big events surge, much depends on the local Plan 2 require big geography and the nature of the storm. Protects Jamaica Bay engineering. A common rule of thumb is that a John F Kennedy NEW I don’t see any wetland extending 14.5 kilometres out YORK International VERRAZANO NARROWS BARRIER Airport other way“ to sea will reduce the height of a storm surge by a metre. But if a storm moves NEW BROOKLYN slowly and winds drive at the coast for Jamaica Bay JERSEY STATEN an extended period of time, these ISLAND benefits can vanish. None of the experts contacted by New Scientist believes the architects’ Rockaway 10 km plans would protect against a major storm. “Big events require big NY-NJ OUTER engineering. I don’t see any other HARBOR GATEWAY way,” says John Mutter of Columbia Sandy Hook University, who studies vulnerability ARTHUR KILL BARRIER ATLANTIC OCEAN to natural disasters. Still, artificial wetlands and other soft engineering approaches could New York City hurricane evacuation zones improve resilience against smaller Highest risk of May experience storm May experience storm storms, and be part of a comprehensive ooding from a surge ooding from a surge ooding from a approach to flood protection. “We hurricane's storm surge moderate hurricane major hurricane need to look to the Dutch,” says Rosenzweig. “They have the barriers, the outer barrier could be built for concerns explain the enthusiasm in but they realise that hard engineering $5.9 billion – including bolstering the some quarters for soft engineering is not going to save them completely.” low-lying peninsulas of Rockaway and solutions, including the construction For instance, in the Netherlands, Sandy Hook to ensure that surges don’t of new wetlands and oyster beds, agricultural land is used to soak up simply flow around it. The East River which can help to slow storm surges. excess water in floods. barrier could cost another $5 billion, The region’s architects have turned Political leaders seem divided on says Bowman. Those are huge sums – these ideas into conceptual designs. how to proceed. While New York state but with losses from Sandy estimated at In 2009, a team led by Guy Nordenson governor Andrew Cuomo has said $50 billion it may be money well spent. of Princeton University completed a that officials need to approach flood Nevertheless, some experts warn study called “On the Water: Palisade protection with an open mind in the against rushing into plans to build Bay”, which envisaged adding an light of Sandy’s devastation, New York massive barriers, which would archipelago of islands and reefs to the City mayor Michael Bloomberg fundamentally change the region’s region, plus an extended waterfront remains sceptical about flood barriers. environment. “We’ve learned in the including tidal marshes, piers and Meanwhile, feasibility studies past several decades that you harm parks. Five teams of architects, alone will take years and cost tens of fisheries if you block estuaries,” says engineers and landscape designers millions of dollars. There will be no Orton. “You reduce the flushing. then refined the plans, which were easy solutions, Rosenzweig warns. Therefore the amount of pollution exhibited in 2010 at New York’s “We need to be very smart. But then in the system is going to grow.” Such Museum of Modern Art.