In the years before Superstorm Sandy struck New York, there was talk of protecting the city by building a giant storm surge barrier — a larger version of the hurricane seawall that protects Stamford, Conn. But the risk of a storm flooding New York was speculative, and the cost of any surge barrier big enough to shelter large parts of the city was sure to be huge. Ideas were floated, but they never went anywhere. Coastal Connection took a look at the proposals last winter ("Storm Surge Floodgates for New York City?" by Ted Cushman, 12/13/2011).

Now the storm isn't fantasy — it's a reality, and its cost, rising into the tens of billions, overtops the back-of-the-napkin estimates for the price tag of protection. In Sandy's aftermath, the discussions of defending New York from the next Sandy — and the one after that — no longer seem quite so theoretical.

The New York Times discussed the issue two weeks ago ("Weighing Sea Barriers as Protection for New York," by Mireya Navarro). The Times story opens with an anecdote about Stamford's surge barrier, completed in 1969. "When storm waters from Hurricane Sandy ripped through the East Coast, much of Stamford, a city of 124,000, sat securely behind a 17-foot-high barrier that easily blocked an 11-foot surge." Stamford's barrier was conceived after Hurricane Carol flooded the city's downtown in 1954; the Corps of Engineers estimates that Carol's damage would have been reduced by 85% had the barrier been in place before the 1954 flood.

Hurricane expert Jeff Masters discussed the Stamford barrier, and a similar dike system at Providence, R.I., last year in a detailed blog post ("Storm surge barriers: the New England experience," by Dr. Jeff Masters, November 25, 2011). "Storm surge barriers in Stamford, New Bedford, and Providence have already proved their worth and prevented damages more than the cost of their construction. For example, the Stamford barrier kept out the storm surge from the December 1992 Nor'easter, which neighboring New York City suffered storm surge flooding of its subway system and roads that caused hundreds of millions in damage. Similar barriers in the Netherlands and England's Thames River have also proved their worth, and multi-billion dollar storm surge barriers are nearing completion in St. Petersburg, Russia and the Venice Lagoon in Italy." Concludes Masters: "There are three locations along the U.S. coast that should immediately begin planning to install hurricane storm surge barriers: New York City, Galveston/Houston, and Tampa Bay."

In Galveston and Houston, concepts have been floated for an "Ike Dike," named after the disastrous Hurricane Ike that pounded the barrier island and narrowly missed the bull's-eye of the Houston Ship Channel. Texas A&M University professor William J. Merrell is the idea's chief proponent, with an Ike Dike home page at the university's website. At Rice University, the "SSPEED Center" — an acronym for "Severe Storm Prediction, Education, and Evacuation from Disasters" — is also pushing the idea with an Ike Dike website.

Galveston city leaders are serious about the idea: They've earmarked $250,000 for a study of the concept, the Galveston Daily News reports ("Isle council approves funding Ike Dike study," by Whitney Hodgin). That's far short of the multi-billion-dollar cost for constructing any workable surge barrier, but it means a lot to Galveston: the sum represents a quarter of the city's budget for economic development.

For New York, Dutch engineering firm Arcadis has sketched a concept for a barrier across the Verrazano Narrows between Brooklyn and Staten Island, the Associated Press reports ("Experts: NYC sea barrier could have stopped surge," by Jennifer Peltz). "It would be supplemented by two smaller barriers, one between Staten Island and New Jersey and the other on the East River," the report says. "Such a barrier would have protected Manhattan and much of Brooklyn and Staten Island from Sandy, but left southern Brooklyn and Kennedy Airport exposed." According to Arcadis engineer Piet Dierke, who helped to implement extensive surge barriers in the Netherlands, baby steps like toughening individual buildings and elevating critical facilities aren't enough to address the problem. Said Dierke: ""With the kind of protection that has been considered so far, you cannot protect a multimillion-inhabitant city that runs part of the world economy,"