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As the center of Hurricane Katrina passed southeast of New Orleans on August 29, 2005, winds downtown were in the Category 1 range with frequent intense gusts and tidal surge. Hurricane-force winds were experienced throughout the city, although the most severe portion of Katrina missed the city, hitting nearby St. Bernard and Plaquemines parishes. Hurricane Katrina made its final landfall in eastern St. Tammany Parish. The western eye wall passed directly over St. Tammany Parish, Louisiana as a Category 3 hurricane at about 9:45 am CST, August 29, 2005.〔() Richard D. Knabb, Jamie R. Rhome, and Daniel P. Brown, National Hurricane Center, “Tropical Cyclone Report Hurricane Katrina”, August 23–30, 2005; retrieved September 11, 2009〕 The communities of Slidell, Avery Estates, Lakeshore Estates, Oak Harbor, Eden Isles and Northshore Beach were inundated by the storm surge that extended over six miles inland. The storm surge affected all of St. Tammany Parish’s coastline, including Lacombe, Mandeville and Madisonville. The storm surge in the area of the Rigolets Pass was estimated to be 16 feet, not including wave action, declining to at Madisonville. The surge had a second peak in eastern St. Tammany as the westerly winds from the southern eye wall pushed the surge to the east, backing up at the bottleneck of the Rigolets Pass. In the City of New Orleans, the storm surge caused more than 50 breaches in drainage canal and navigational canal levees and floodwalls.〔http://levees.org/wp-content/uploads/2010/07/levee.pdf〕 The failures of structures are considered by experts to be the worst engineering disaster in the history of the United States.〔http://levees.org/2/wp-content/uploads/2014/12/WFMarcusonIII_a_-1.pdf〕 By August 31, 2005, 80% of New Orleans was flooded, with some parts under of water. The famous French Quarter and Garden District escaped flooding because those area are above sea level. Responsibility for the performance of the city's levees belongs to the United States Army Corps of Engineers. The major breaches included the 17th Street Canal levee, the Industrial Canal levee, and the London Avenue Canal floodwall. These breaches caused the majority of the flooding, according to a June 2007 report by the American Society of Civil Engineers. The flood disaster halted oil production and refining which increased oil prices worldwide. Between 80 and 90 percent of the residents of New Orleans were evacuated before the hurricane struck, testifying to some of the success of the evacuation measures. Despite this, many remained in the city, mainly those who did not have access to personal vehicles or who were isolated from the dissemination of news from the local governments. The Louisiana Superdome was used to house and support some of those who were unable to evacuate. Television shots frequently focused on the Superdome as a symbol of the flooding occurring in New Orleans. 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 Army Corps of Engineers and the failure of portions 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.〔John A. Kilpatrick and Sofia Dermisi, "The Aftermath of Katrina: Recommendations for Real Estate Research", ''Journal of Real Estate Literature'', Spring, 2007.〕 == Background == New Orleans was settled on a natural high ground along the Mississippi River. Later developments that eventually extended to nearby Lake Pontchartrain were built on fill to bring them above the average lake level. Navigable commercial waterways extended from the lake into the interior of the city to promote waterborne commerce. After the construction of the Inner Harbor Navigation Canal in 1940, the state closed these waterways causing the town's water table to lower drastically. In 1965, heavy flooding caused by Hurricane Betsy brought concerns regarding flooding from hurricanes to the forefront. That year Congress passed the Flood Control Act of 1965 which, among other issues, gave authority for design and construction of the flood protection in the New Orleans metropolitan area to the United States Army Corps of Engineers subject to cost sharing principles, some of which were waived by later legislation. The local municipalities were charged with maintenance once the projects were completed. After 1965, the corps built a levee system around a much larger geographic footprint that included previous marshland and swamp. Many new subdivisions were developed to cater to those who preferred a more suburban lifestyle but were open to remaining within the city limits of New Orleans. Historians question why the area farthest east was developed, since it was viable wetlands and because ringing this region with levees did nothing significant toward protecting the city. What expansion accomplished was to increase the amount of land that could be developed, and it was a reason for the Army Corps to expand the size of its project. In addition the structures caused subsidence of up to in some areas due to the consolidation of the underlying organic soils A 1999–2001 study Richard Camapanella, Tulane School of Architecture, using LIDAR technology found that 51% of the terrestrial surface of the contiguous urbanized portions of Orleans, Jefferson, and St. Bernard parishes lie at or above sea level, with the highest neighborhoods at above mean sea level.〔http://richcampanella.com/assets/pdf/study_Campanella%20analysis%20on%20Above-Sea-Level%20New%20Orleans.pdf〕 Forty nine percent percent lies below sea level, in places to equivalent depths. When authorized, the flood control design and construction were projected to take 13 years to complete. When Katrina made landfall in 2005, the project was between 60–90% complete with a projected date of completion estimated for 2015, nearly 50 years after authorization.〔http://www.gao.gov/new.items/d051050t.pdf〕 Moreover, another major hurricane flooding had long been predicted, and while the close call of Hurricane Georges in September 1998 galvanized some squabbling scientists, engineers and politicians into collective planning, as at October 2001, ''Scientific American'' declared that "New Orleans is a disaster waiting to happen".〔Fischetti, Mark (October 2001), p.70〕 However, even the most insistent calls to evacuate before Katrina, did not warn that the levees could breach.〔http://www.huffingtonpost.com/sandy-rosenthal/katrina-levees-warning_b_1001777.html〕 On August 29, 2005, flood walls and levees catastrophically failed throughout the metro area. Many collapsed well below design thresholds (17th Street and London Canals). Others collapsed after a brief period of overtopping (Industrial Canal) caused “scouring” or erosion of the earthen levee walls. In eastern New Orleans, levees along the Gulf Intracoastal Waterway failed in several places because they were built with sand and erodible materials instead of clay, an obvious construction flaw. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Effects of Hurricane Katrina in New Orleans」の詳細全文を読む スポンサード リンク
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