25th - 26th SEPTEMBER 2019  |  OLYMPIA

How Airports Are Protecting Themselves Against Rising Seas

Wired 02 Dec 2019 12:00

Next fall, San Francisco International Airport plans to begin environmental studies for its next big construction project. The $587 million project, targeted for completion in 2035, won’t produce another terminal, runway, or amenity for the airport’s 55 million annual passengers. It will be a seawall, an 8-mile-long bastion of steel and concrete. It will also be the centerpiece of SFO’s plan to protect itself from the steady rise of San Francisco Bay.

Since the 1980s, SFO has installed a variety of features to protect itself from the risk of flood associated with rising waters, including berms, concrete walls, and the kind of sheet piling construction projects use to keep water out of building sites. The new wall betrays a bolder ambition, to keep the airport’s facilities and four runways dry for the next half century or more. That means building to protect against 3 feet of sea level rise, the level anticipated by 2085. And while San Francisco International has one of the better-defined plans for warding off the water, it’s far from the only American airport facing this challenge.

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Rising tides may lift boats, but they can sink airplanes. According to the 2014 National Climate Assessment, 13 of the country’s 47 largest airports have at least one runway that’s vulnerable to moderate or high storm surge. Along with San Francisco and its across-the-bay buddy Oakland International, these include the New York area trio of Kennedy, LaGuardia, and Newark. Boston’s Logan and Philadelphia International are at risk, as are Washington, DC’s Reagan and Honolulu International. The waters pose a threat to airports in Fort Lauderdale, Florida, Miami, New Orleans, and San Juan, Puerto Rico. It’s not that the waters will come up and swallow these places the way an incoming tide swallows a sandcastle—at least not this century. Rather, the higher water levels will exacerbate the effects of storms, making floods more common and damaging.

The list of threatened airports is long because coastal areas make for good places to put planes: They tend to be flat and low-lying, and their bodies of water provide lots of open space for arriving and departing aircraft. But as climate change takes hold—spurred on by the emissions that jet aircraft pump into the atmosphere—that convenience has become a vulnerability. And though airports have long been aware of that shift, the pummeling that Superstorm Sandy dealt to New York City in 2012 made clear the severity of the problem. Water overtook LaGuardia’s runways and damaged electrical infrastructure, forcing a three-day closure that cost millions.

Like most problems posed by a shifting climate, the fixes are neither easy nor cheap. The obvious option is to keep the water out. That’s the goal of SFO's seawall. Oakland's airport plans to fortify and raise by 2 feet the 4.5-mile dike that separates its main runway and terminals from the bay. That should cover it until 2050, for $46 million.

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Airports are packed with guts passengers rarely see or think about, none of which do well in floods. These include electrical systems, plumbing lines, telecoms, mechanics like air intakes, ventilation fans and ducts, medical and safety supplies, smoke and fire alarms, record storage, and hazardous materials such as jet fuel and chemicals. To protect such facilities, the Massachusetts Port Authority, which oversees Boston's Logan, issued a floodproofing design guide in 2014 that called for a mix of “dry” and “wet” approaches. Dry floodproofing means keeping the water out altogether, using things like flood barriers in doorways and staircases, and using aquarium glass that can hold back a wave of H2O. The wet way allows more water in, but ensures that all vulnerable infrastructure is well above the point it will reach. For existing facilities, Massport set that point at 13.7 feet above sea level, projected to keep it dry until 2030. New facilities will have to meet the 2070 height of 17 feet.

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