Interaction between the US Army Corps of Engineers and the Orleans Levee Board preceding the drainage canal wall failures and catastrophic flooding of New Orleans in 2005

The authors hope to correct any premature conclusions about the role of the pre-Katrina Orleans Levee Board (OLB) in the failure of the outfall drainage canals in New Orleans during the 2005 hurricane – conclusions that appear to have been based on inaccurate information and/or assumptions. With regard to the 17th Street and London Avenue Canals, the authors have not uncovered any information that would suggest that the OLB behaved irresponsibly in its duties. What is evident from the project record is that the Army Corps of Engineers recommended raising the canal floodwalls for the 17th Street Canal, but recommended gated structures at the mouths of the Orleans and London Avenue Canals because the latter plan was less expensive. The OLB convinced Congress to pass legislation that required the Corps to raise the floodwalls for all three canals. Furthermore, the Corps, in a separate attempt to limit project costs, initiated a sheet pile load test (E-99 Study), but misinterpreted the results and wrongly concluded that sheet piles needed to be driven to depths of only 17 feet (1 foot = 0.3048 meters) instead of between 31 and 46 feet. That decision saved approximately US$100 million, but significantly reduced overall engineering reliability.