Here's an extract from an article that provides some insight into the matter of the levee design that's already a topic for critics. A category 6 hurricane could hit any coastal area of our nation tomorrow and cause massive destruction. Even if we built a 30 foot high 250 foot wide reinforced levee around every mile of our coast line it still could not be guaranteed it would prevent all damage. Nothing we do is absolutely fail-safe, perfect, or permanent even if it's expensive. All things designed and built by mankind are, at best, compromises of knowledge, skill, time, money, and other factors. We are frequently humbled when we think we have it all mastered. The whole Mississippi River valley has been prone to flooding since man first came to settle here. Thanks to a lot of hard work by a lot of people we have much better flood control structures. But it is still an imperfect system. There has been far less suffering from flooding in the lower Mississippi River valley than just a few generations ago. Never the less, there is still flooding when levees break because, like all things man made, they can and do fail. Knowledge of how to design these structures continues to improve. Arguments still continue as to what's best. Folks in one area want the water diverted to another. The conflict in Louisiana itself over the Mississippi verses the Atchafalaya continues to this day. There are compromises with everything that's been done and everything we could do. Due diligence, honest evaluation, reasonable assumptions, etc. are all to be expected. Perfection and accurate prophecy can not to be assured.