The cost of the surge barriers alone in Holland was as much as €30 billion in 2008 values, Aerts said.
The stiff price of doing nothing
He estimated the cost of building a series of barriers around New York City at between $13 billion and $22 billion, in addition to annual operational costs, which could run between $70 million and $130 million a year.
The overlapping jurisdictions of local, state, regional and federal governments that ensure a tangle of regulatory hurdles make construction of large storm barriers more complicated in the New York City region than in the Netherlands, he said.
"Permits are an issue, and who is responsible for operational costs," Aerts said.
More generally, he said, New York City needs to develop a culture of flood risk management where rather than dozens of specialists, there might be thousands.
Klaus Jacob, a geophysicist at the Lamont-Doherty Earth Observatory at Columbia University, said the 100-year flooding event of today will occur roughly every 50 years in the 2020s, every nine to 20.5 years in the 2050s and every 1.1 to 3.4 years by the 2080s.
"Storm surge barriers are good for the purpose of keeping out storms, but they don't keep out sea level rise," Jacob said.
The city is projected to face sea level rise of 5 to 6 feet by century's end, a level comparable to the surge brought about by Superstorm Sandy, which occurred during a high tide.
So even on a nice, sunny day at the end of the century, the city may see water levels comparable to those that occurred during Sandy. Manhole covers will need to be replaced, subway entrances made less prone to flooding, and drainage grates elevated. Thousands of small improvements, he said, will need to be undertaken, regardless of building storm barriers around the city such as the Netherlands has done.
A key challenge that has gone overlooked by city planners, Jacob said, is the growth in population in many of the low-lying areas of Manhattan and Brooklyn that are vulnerable to sea level rise and storm surges.
"We have to change our demography, our urban planning, our social engineering," he said.
Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500