This is the first in a series of posts that will describe a portable hurricane storm surge barrier that I think could--and should--be built. The barrier would be capable of being deployed to protect approximately 100 miles along the U.S. Gulf Coast or East Coast in a matter of days. I will eventually outline one possible design for such a system. My point in outlining one possible design is not to suggest that such a design is the best design, but simply to illustrate that such a system is in no way some science-fiction fantasy that could never be built and deployed.
Why build such a barrier? In a word, "Katrina." Or simply, "New Orleans." But also, "Miami." "Fort Lauderdale." "Tampa/St. Petersburg." "Jacksonville." "Galveston." "Virginia Beach." "Washington DC." "New York City."
The simple fact is that a major hurricane could strike anywhere along the Gulf Coast (1600 miles) or East Coast north to approximately Boston (another approximately 1600 miles). Currently, measures are being designed or envisioned that can partially protect single cities (e.g. levees and flood gates for New Orleans, flood gates for New York City). However, it would make more sense from an economic and engineering standpoint to design something that could protect approximately 100 miles of coastline days before a storm hits, rather than to protect individual cities by designing something that may not be challenged for many decades (during which time better systems could be built).
The damage from hurricane Katrina was virtually all caused by storm surge (rather than wind damage or inland flooding due to rain). Wikipedia currently estimates that the total economic damage to Louisiana and Mississippi may exceed $150 billion. That's just a single hurricane, and a single city. Moving to New York City, it's been estimated that there is an approximately 1-in-4 chance that a Category 3 or hurricane will hit New York City/Long Island in the next 50 years. Here are storm surge maps calculated by the SLOSH computer model, for various hurricanes hitting New York City and Long Island
Roger Pielke Jr. and others have estimated that if the Great Miami hurricane were to hit Miami in 2020, damages would be approximately $500 billion. (That's half a TRILLION dollars!)
Clearly, the risk of such economic consequences alone warrants significant thought about how to design and deploy such a hurricane storm surge protection system.