The effect of Hurricane Katrina on New Orleans, Louisiana was catastrophic and long-lasting. As Katrina passed east of New Orleans on August 29, 2005, winds were in the Category 1 or 2 range, and tidal surge was about a Category 3. Though Katrina missed the city, the storm surge caused levee breaches and precipitated the worst engineering disaster in US history.
By August 31, 2005, eighty percent of New Orleans was flooded, with some parts under 15 feet of water. Most of the city's levees built by the United States Army Corps of Engineers were breached, including the 17th Street Canal levee, the Industrial Canal levee, and the London Avenue Canal floodwall. These breaches are responsible for at least two-thirds of the flooding according to a new report by the American Society of Civil Engineers.
Ninety percent of the residents of southeast Louisiana were evacuated in the most successful evacuation of a major urban area in the nation's history. Despite this, many remained (mainly the elderly and poor). The Louisiana Superdome was used as a designated "refuge of last resort" for those who remained in the city. The city flooded due primarily to the failure of the federally built levee system. Many who remained in their homes had to swim for their lives, wade through deep water, or remain trapped in their attics or on their rooftops.
The disaster had major implications for a large segment of the population, economy and politics of the entire United States. It has prompted a Congressional review of the US Army Corps of Engineers and the failure of the federally built flood protection system which experts agree should have protected the city's inhabitants from Katrina's surge. Katrina has also stimulated significant research in the academic community into urban planning, real estate finance, and economic issues in the wake of a natural disaster..