Why did the levees break?
“There were two direct causes of the levee breaches: collapse of several levees with concrete floodwalls (called I-walls) because of the way they were designed, and overtopping, where water poured over the tops of the levees and floodwalls and eroded the structures away. Furthermore, the many existing pump stations that could have helped remove floodwaters were inoperable during and after the storm.
