WE NOW know how it happened, but whether it could have been prevented is still hotly disputed.
The US Army Corps of Engineers has acknowledged for the first time that the New Orleans 17th Street Canal levee was breached during hurricane Katrina because of a failure in the system, rather than because the storm exceeded the levee’s design specification (New Scientist, 25 February 2006, p 8).
On 10 March, the corps released an interim report saying the levee split in two when its steel-supported concrete walls tilted. That, and a weak layer of clay in the soil near the…
