The ‘Control’ of Nature in New The ‘Control’ of Nature in New Orleans: The Past, Present, and Orleans: The Past, Present, and Future of the Mississippi DeltaFuture of the Mississippi Delta

Catherine RiihimakiCatherine Riihimakiandand

Rheanna BenselRheanna Bensel

No one could have predicted this event…Numerous government officials post-Katrina

 It's only a matter of time before South Louisiana takes a direct hit from a major

hurricane. Billions have been spent to protect us, but we grow more vulnerable every day.

Times-Picayune, June 23-27, 2002Five-Part Series on flooding hazards in N.O.

LSU, Center for the Study of Public Health Impacts of Hurricanes

“The Army Corps of Engineers says the system will protect the city and suburbs from a Category 3

hurricane that pushes in enough seawater to raise Lake Pontchartrain 11.5 feet above sea level -- high over the head of anyone standing on the other side

of a levee.”--Times-Picayune, 2002

US Army Corps of Engineers, New Orleans District

Breached Industrial Canal levee, with water

flowing OUT of a residential areaAugust 30, 2005

Humans have dramatically changed the distribution of sediment in the Mississippi River system.

• Sediment compacts under its weight; exacerbated by dewatering of sediment (present rate of compaction is ~10x natural rate)

• In New Orleans…Levees prevent new deposition of sediment; nothing to counteract subsidence

change in elevation = new sediment - subsidence

Humans have dramatically changed the distribution of sediment in the Mississippi River system.

• Sediment compacts under its weight; exacerbated by dewatering of sediment (present rate of compaction is ~10x natural rate)

• In New Orleans…Levees prevent new deposition of sediment; nothing to counteract subsidence

• Sediment load of Mississippi drops off continental shelf; coastal erosion is therefore faster

change in coastline = new sediment - wave erosion

We ought to take a second look at it. But you know we build Los Angeles and San Francisco on top of earthquake fissures and they rebuild

too. Stubbornness.-- Dennis Hastert

Fundamental observation (thanks to Arshiya Bose)…

Natural disasters are primarily disastrous because of how humans interact with

nature

Fundamental question…How do we deal with dynamic natural systems with a static economy?

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