The only way the levees could be built to withstand the surge from a cat 5 storm would require making the bases 3-5 times wider than they are now, which would destroy much of the city. IMHO, what needs to be done is that the the levees need to be rebuilt to their original design specifications (not what was built) and that a storm surge control structure, capable of withstanding a 40+ foot surge be built at the mouth of Lake Ponchatrain. Such protective structures are relatively common across Europe (Holland in particular). But (and there's always a but) dealing with the enviros will be a big problem. The enviros (and yes, poor planning) stopped a Lake Ponchatrain surge gate in the 1970's.

JimJr - Only 200 miles north New Orleans