In late August 2005 there were over 50 failures of the levees and flood walls protecting New Orleans, Louisiana, and nearby St. Bernard Parish during Hurricane Katrina. The levee and flood wall failures caused flooding in 85% of New Orleans and 100% of St. Bernard. Millions of gallons of water spilled into vast areas of New Orleans, flooding thousands of homes and businesses with 10 feet or more of water. Five investigations (three major and two minor) were conducted by civil engineers and other experts, in an attempt to identify the underlying reasons for the failure of the federal flood protection system designed and built by the United States Army Corps of Engineers. To date, the studies disagree on the mechanisms of the levee failures. Fault has been aimed at the Corps of Engineers, their local contractors, and local levee boards. Storm surge caused breaches in 20 places on the Mississippi River-Gulf Outlet Canal ("MR-GO") flooding the entire Saint Bernard Parish and the East Bank of Plaquemines Parish. Three major breaches occurred on the Industrial Canal; one on the northeast side near the junction with Gulf Intracoastal Waterway and two on the southeast side along the Lower Ninth Ward, between Florida Avenue and Claiborne Avenue. On the east side of New Orleans the 17th Street Canal levee breached below design specs on the New Orleans side near the Old Hammond Highway Bridge. The London Avenue Canal breached in two places, near Robert E. Lee Boulevard, and near the Mirabeau Avenue Bridge.

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