Rising waterFlood-proofing New York City with storm barriers

Published 1 June 2009

New York City faces two problems with water: rising ocean level and surges created by hurricanes and Nor’easters; engineers propose a system of barriers to prevent New Orleans-like flooding

When experts sketch out nightmare hurricane scenarios, a New York strike tends to be high on the list.

The Atlantic Ocean poses two threats to New York City — one a more distant threat, the other more immediate. The more distant threat is the fact that climate change causes the ocean level to rise — but rise unevenly. There are two problems here: First, rather than spreading out evenly across all the oceans, water from melted Antarctic ice sheets will gather around North America and the Indian Ocean. This is bad news for the U.S. East Coast, which could bear the brunt of one of these oceanic bulges (see HS Daily Wire). Second, although low-lying Florida and Western Europe are often considered the most vulnerable to sea level changes, the northeast U.S. coast is particularly vulnerable because the Atlantic meridional overturning circulation (AMOC) is susceptible to global warming (see HS Daily Wire) (also see article elsewhere in this issue).

Now, to the more immediate threat. The dangers hurricanes pose to NYC is not that the city’s tall buildings will shake, but that the storm could send the Atlantic Ocean surging into the U.S. largest city, flooding Wall Street, subways and, densely populated neighborhoods. Today marks the start of this year’s hurricane season, and Phyorg.com reports that some scientists and engineers are floating an ambitious solution: Barriers to choke off the surging sea and protect flood-prone areas (see also 7 April 2009 HS Daily Wire).

The plan involves deploying giant barriers and gates that would move into place — in some cases emerging out of the water — for storms. One proposal calls for a 5-mile-long barrier between New Jersey and Queens.

No one has formally proposed the structures, which would require extensive government reviews and billions of dollars. A conference on the subject this spring drew 100 researchers and engineers, who provided different conceptual designs (the plan described above was offered by Graeme Forsyth and Dennis Padron from the U.K. engineering group Halcrow). NYC emergency management officials say they are interested in hearing more if details develop.

Some scientists have questioned whether the barriers would be environmentally sound and socially equitable. Proponents, however, say the structures could offer the best chance of preventing catastrophe in a city with hundreds of miles of shoreline, nearly 8.3 million residents, and a sprawling web of crucial underground infrastructure. New Yorkers are “living under the volcano, and people haven’t thought about it,” says Douglas Hill, an engineer