HURRICANE KATRINA FLOOD BY: JESSICA KANG

Facts Formed over the Bahamas on August 23, 2005 Crossed southern Florida (category 1) Turned into category 3 on August 29, 2005 and caused severe damage along the Gulf Coast from central Florida to Texas The most severe damage occurred in New Orleans, Louisiana

More Facts At least 1,836 lives were lost, making it one of the deadliest U. S. hurricanes 705 are still missing Costliest hurricane: $88.5 billion

History New Orleans is located on a delta formed by the Mississippi River First settled by the French on the natural levee along the Mississippi bank (known today as the French Quarter) North of the natural levee, the land slopes down into a swamp

History Around 1900, large pumps were introduced to drain this wetland ◦Water was pumped up into canals and drained into Lake Pontchartrain By 1950, houses and buildings made up the city that we know of today

Geologic Setting Since New Orleans rests on a delta and it is being drained, the city is continuously sinking This is because there is peat (unstable organic soil) found in the swamp

Three Processes Behind Ground Subsidence on Peat ◦“Consolidation due to loss of water, when the peat loses volume in response to the loss of support offered by internal water pressure ◦Compaction under load, both self-loading and imposed by other sediments or built structures, when the highly porous peat restructures into a denser material ◦Wastage on exposure to air, when the peat simply oxidises and disappears where loss of water leaves it above the water table.”

Artificial Levees Knowing that the natural levees would not be enough to protect this sinking city, artificial levees were built. But they weren’t enough to withstand Katrina...

How the Levees Failed Caused by under seepage through the levee silt The silt washed out and formed “cavities” in the levees, which grew larger Eventually, the levees collapsed

Solutions: It’s Complicated! To rebuild or not to rebuild... Ethical issues ◦Rebuild  Continue building higher levees as the city keeps sinking  Is it the right thing to do to rebuild in a hurricane prone area? ◦Not to Rebuild  Most people want to hear good news ◦ In the short-run it may be good, but in the long-run?  Who is going to be responsible for the victims? ◦ Many victims were thrown out of their trailer that was provided as shelter after the disaster ◦ Government aid has also been cut off

Works Cited Risk Management Solutions Inc. “Hurricane Katrina: Lessons of a Super Cat.” Web. 24 Feb Robertson, Ian N. "Lessons from Hurricane Katrina storm surge on bridges and buildings." Journal of Waterway, Port, Coastal and Ocean Engineering (2007): GeoRef. EBSCO. Web. 24 Feb Waltham, Tony. "The flooding of New Orleans." Geology Today 21.6 (2005): GeoRef. EBSCO. Web. 24 Feb Hurricane Katrina