Lessons Learned from the Levee Failures in the New Orleans Area and their Impact on Levee Design and Assessment across the Nation

Abstract

In August 2005, Hurricane Katrina made landfall just east of New Orleans and inflicted widespread damage on the Hurricane Protection System (HPS) for southeast Louisiana. The storm surge produced by Hurricane Katrina in some cases overwhelmed the HPS beyond its design, but in other cases levee failures occurred at water levels well below their design. The response to this disaster by the US Army Corps of Engineers (USACE) included forming an Interagency Performance Evaluation Taskforce (IPET) to study the response of the system and, among many lines of inquiry, to identify the causes of failure of levees and floodwalls. Beginning in September 2005, the IPET gathered forensic geotechnical data from failed portions of levees and floodwalls. These data were considered perishable and had to be gathered quickly due to levee rebuilding operations. The performance of the levee and floodwall system provided valuable lessons. These lessons consist of: the need for resilience of the HPS; the need for risk-based planning and design approach; and the deficiency in knowledge, technology, and expertise in the hurricane protection system arena. The rebuilding efforts and future assessments and designs of hurricane protection systems will incorporate the lessons learned.