"Something like half of New Orleans is now below sea level -- as much as fifteen feet. New Orleans, surrounded by levees, is emplaced between Lake Pontchartrain and the Mississippi like a broad shallow bowl. Nowhere is New Orleans higher than the river's natural bank. Underprivileged people live in the lower elevations, and always have. The rich -- by the river -- occupy the highest ground. In New Orleans, income and elevation can be correlated on a literally sliding scale: the Garden District on the highest level, Stanley Kowalski in the swamp.
"Among the five hundred miles of levee deficiencies now calling for attention along the Mississippi River, the most serious happen to be in New Orleans."
Thanks to Michael Dudley