New Orleans Levee System

In August of 2005, Tropical Storm Katrina hit New Orleans head on and devastated the area by flooding the entire city.  The nation was on high alert this past week when tropical storm Gustauv headed straight towards New Orleans.   I feel horrible for the people that live in this area mostly for how the government, namely FEMA handled the situation after Katrina hit.  It seems as though not much has been done to help the people of New Orleans rebuild in the past 3 years.  All are relieved to see that the levee system did its job and held back the storm surges that came with Gustauv.  

Tonight I started wondering about the levee system surrounding New Orleans.  I only know a couple of things about New Orleans with the first being that 70% of the town is built below sea level.  So I started thinking "there must be a pretty impressive levee system built that holds back water to protect one of the most well known cities in the U.S.".  With a bit of searching this is what I found.

I started with this basic illustration of how New Orleans is protected....  Parts of the city are 10 feet below sea level.  There are two levee systems that protect the city.

I was then curious what the walls looked like up close.   

17 foot, cement walls protect this entire city from flooding each and every hurricane season. I see more impressive walls built driving around town.  No wonder it broke and gave way.  And in their rebuilding efforts, the Army Corp of engineers rebuilt and repaired 41 miles of damaged wall.  And the people in New Orleans are expected to trust this and move their families back into this volatile area?  Each hurricane season are we going to evacuate the entire city?  So then i wondered what could be done...  

The Netherlands has the Delta Works that protects the 60% of the population that live below sea level.  This is a pretty impressive project that has been named one of the seven wonders of the modern world.

Good work Dutch people...  

England has the Thames Barrier that prevents London from being flooded by high tides and storm surges.  Also pretty impressive.

So why cant we....  or better yet...  why don't we build something a bit more impressive than a cement wall to protect such a big part of our American culture in the south??  Does it cost too much money??  To difficult to build??   Can anyone out there help me understand?