Answers from Army Corps of Engineers on unwatering New Orleans

WWL-TV New Orleans, 11:28 PM CDT on Tuesday, August 30, 2005

Q.2. Why did the levees fail?

A.2. What failed were actually floodwalls, not levees. This was caused by overtopping which caused scouring, or an eating away of the earthen support, which then basically undermined the wall.

These walls and levees were designed to withstand a fast moving category 3 hurricane. Katrina was a strong 4 at landfall, and conditions exceeded the design.

Q.3. Why only Category 3 protection?

A.3. That is what we were authorized to do.

(via InstaPundit)