Engineers Prepare for
Surges Ahead


February 2013

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With the destruction wrought by Hurricane Sandy not yet repaired, there's been a call by the public, engineers, oceanographers, and policy makers, for action to protect people from the next one. "Barriers should be built across the Narrows," wrote Malcolm Bowman, a professor of oceanography at the School of Marine & Atmospheric Sciences, in the New York Times. "These three barriers, high enough (not less than 25 feet above sea level) to withstand any conceivable storm surge, closed before a major storm, would provide a ring of shelter around the city."

The call, though, is not a new one, as the words above were printed in 2005.

Engineers and scientists prophesized a Katrina before it flooded New Orleans. And they warned about New York and New Jersey's vulnerability long before Sandy. The year before Hurricane Katrina, Joannes Westerink, a professor of civil engineering and geological sciences at Notre Dame, ran a simulation with his Advanced Circulation Model that showed how New Orleans' levees would not stop a flood made by a large, slow, category three hurricane. And, at a 2009 American Society of Civil Engineers conference, engineers warned of the risks to the New York area. Their models showed how a strong storm could cause a surge, and where the water would flow. They presented a detailed outline for how and where to build storm surge barriers, pointing to the successes and methodologies of barriers found elsewhere in the world.

"I've been telling people for years," says Bowman. "It was not a question of if, but when. People in government didn't dispute that—they understood it. But in terms of doing anything about it, that's a whole other story."

Now, thanks to Sandy, national attention has been successfully turned to the potential damage of powerful storms. Maybe it's time to ask, "Who else is at risk?" Do those seers who warned us early on of possible Katrinas and Sandys have other words of warning so that we might once make truly preventive measures?

The answer to the simple question of who else is at risk, isn't so simple.

There’s been a call by the public, engineers, oceanographers, and policy makers, for action to protect people from future storms in the wake of Hurricane Sandy.

Risk Assessment

"Basically the entire east coast is vulnerable," says Anne Dudek Ronan, professor of civil engineering at the Polytechnic Institute of New York University.

"And nature will not tell us in advance where the next hurricane will go." Baltimore, Washington, D.C., Miami: if the tides are high, the storm big enough, the trajectory right, all would be at risk. As has been made clear, historically unprecedented does not mean impossible.

"Basically there's knowledge about ground elevation everywhere. If you know how high the ground is and you know the water surface will be higher than the ground, you've got flooding."

If a Category Four hurricane were to land in Boston, unlikely though that is, it would be underwater.

What's to be done, then? "One big long barrier along the coast? Can you imagine a ten-foot-high wall along the coast?" asks Ronan. Barriers large and small come with huge costs, monetary and otherwise. Barriers in New York alone are predicted to sap taxpayers of 15 billion or so. The environmental impact would be substantial as well. And while a barrier protects the population on the coast it runs along, it makes any surge worse for neighbors on either side of it, because, as engineers know, the water must go somewhere.

Stronger Foundation

A more manageable solution might be to waterproof buildings and retrofit their foundations. Building codes in Florida changed after Hurricane Andrew hit the state in 1992. When a similar-sized Hurricane Wilma came along thirteen years later, its high winds did much less damage.

But Ronan points out that it's not only hurricanes that can cause flooding. The Sacramento–San Joaquin River Delta is far inland from the Pacific Ocean where its waters eventually flow. The delta's levees have reached new levels of vulnerability. "The structural integrity of certain pieces has been called into question," says Ronan. "But there is a big time lag between determining need and action."

Inaction, at the delta or along the east coast, may not be as important as accountability and transparency, says Robert Weisberg, a professor of Oceanography at the University of Florida. "You're not going to change nature, nature is going to do its thing. But how we present ourselves to nature is something we can control. It's really the development of the shorelines that increase the potential for death and damage rather than the storms themselves. We have to deal with it when it happens."

Decisions to develop swaths of oceanfront property should be made with better knowledge of the risks. According to Weisberg, there's too much backroom politics when it comes to how flood insurance maps are drawn. "If we're aware of what the potential problems may be in a given area we can factor that into our development," he says.

"We can make improvements in the models that we are using in our risk analysis, and we can make improvements in how the information is promulgated to the public, and we can raise the level of accountability on everyone that's in control of that information."

But if better information, stewarded by responsible leaders, reaches the public, it is not clear what affect it will have. Will a risk-averse percentage of the population give up on the seaside dream and head to higher ground? "We're all human beings, and our aesthetics are important," says Weisberg. "We want to live happy lives, but we must be cognizant of the risks."

Bowman, though, says get to it, or else. "My warning is: 'Start planning now—the experience in other countries is that it takes decades. No one's talking about pouring concrete next week, but the planning must start.'"

Michael Abrams is an independent writer.

Basically the entire east coast is vulnerable, and nature will not tell us in advance where the next hurricane will go.

Malcolm Bowman, professor of oceanography, School of Marine & Atmospheric Sciences

 
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