It is almost five years since hurricane Katrina devastated New Orleans, and the city is bracing for other attacks to come. In a revamp now nearing completion, the city’s 560-kilometer perimeter has been fortified by toughened levees, cement walls more than 9-meters high, and imposing gates that will grind shut when flood water nears (“New levee design, construction materials tested in Louisiana,” 23 August 2010 HSNW).
Some say that these upgraded defensces, which cost the U.S. federal government $14.45 billion, are not tough and comprehensive enough — in part because climate change lead to more powerful storms.
Sujata Gupta writes in New Scientist that the city is certainly safer than it was on 29 August 2005, when Katrina made landfall. Its 8.5-meter surge went on to overpower a poorly constructed and poorly connected levees and flood walls.