Drainage in New Orleans - Hurricane Katrina - After Katrina

After Katrina

Main article: 2005 levee failures in Greater New Orleans See also: Civil engineering and infrastructure repair in New Orleans after Hurricane Katrina

By the start of October 2005, only a few small areas of flood waters remained within the city, but the disastrous flooding in the aftermath of Katrina left the majority of the city's houses and businesses so damaged as to be unusable until major renovations or repairs could be made. An article in the New Orleans Times-Picayune on 30 November 2005 reported that studies showed the 17th Street Canal levee was "destined to fail" as a result of fundamental design mistakes by the United States Army Corps of Engineers.

Additional investigations have found more problems with the design and construction of the London Avenue Canal, Industrial Canal, MRGO, and other levees and flood walls.

While the majority of the city's drainage pumps were able to be reactivated after the storm, some of the usually reliable pumps failed in 2006 due to corrosion. This was caused by wiring being submerged in the brackish water from Katrina.

As a stop-gap measure, the Corps of Engineers installed flood gates at the mouths of the drainage canals at Lake Pontchartrain, to be closed if the lake water level rises. While this prevents lake waters from flowing into the vulnerable canals, it also severely limits the ability of the city to pump out rain water while the gates are closed.

In March 2006, it was revealed that temporary pumps installed by the USACE were defective. Until all problems are rectified, concerns remain that parts of the city could experience significant flooding in a storm much smaller than Katrina. The system did survive during Hurricane Gustav in 2008. The storm weakened and brought less wind and rain than forecast. "The Lakefront pumps operated smoothly".