Some 80% of New Orleans was devastated by flooding created by the storm surge from Hurricane Katrina in August 2005.

One year on, the city’s levees and floodwalls have been repaired to a standard equalling their prior condition. Temporary floodgates and pumps at the city’s four main canal entrances - which allowed storm surges from Lake Pontchartrain to overwhelm internal flood defences - are almost complete.

The US Army Corps of Engineers, which has been overseeing the work, is examining a number of longer-term options to defend the canal entrances, including a design for floating barge dams equipped with built-in “bowthruster” pumps to repel storm surges.

Despite this work, critics say not enough has yet been done to improve the city’s storm protection system.