Why the new Orleans Levees Failed during Hurricane Katrina

Hurricane Katrina struck the U.S. Gulf Coast in August 2005.  With winds that topped out at 175 MPH, and a storm surge that reached as far as 20 miles inland at some points, Katrina wreaked havoc throughout the region.  The confirmed death toll was 1,836; the true death toll was no doubt higher.  (And if you include the long term effects of stress, grief, poverty, etc., those who have and will have their life shortened by Katrina is far greater still.)  In addition, Katrina is estimated to have caused over $80 billion in property damage.

Sustaining a great deal of the human and property damage was the greater New Orleans area.  New Orleans would have taken a beating regardless, but what turned Katrina from an inconvenience into a catastrophe for the city was the utter failure of the levee system, leaving 80% of the city and neighboring areas flooded.

A proper, well-functioning levee system is crucial to the survival of the city of New Orleans, large parts of which lie below sea level. 

The question of why the New Orleans levees failed can be taken in different ways.  First there is the question of what there was about them, physically, that resulted in their failing.  That is a matter of physics, of engineering.  But beyond that, there is the question of why they were built that way in the first place, and never properly upgraded.  That is a matter of politics, of economics, of human evil and weakness.

Among the structural reasons investigators found for the failure of the levees were these:

* In some areas, the storm surge overtopped the levees.  Soil on the landward side was then eroded, causing levee sections to fail.

* In some areas, the surge percolated through layers of peat, sand, and clay under the sheet pilings of the levees, especially where the pilings were not driven far into the ground.  Once the water was on the landward side, it had the same erosive effect as where the surge overtopped the levees.

* In some areas, the surge exploited weaknesses between different kinds of levees.

* In some areas where levees were made from fill or dredge material from canals, there was insufficient marshland in front of them to protect them from the surge.

The fact is, a significant amount of these and other problems with the levees were understood in advance.  There was no shortage of warnings that the levees could catastrophically fail in the event of a hurricane striking New Orleans.

But this is where the human failings enter the picture.  The money and the political will were lacking to build the levees properly.  As Leonard A. Shabman, an investigator who headed up a team commissioned by the Army Corps of Engineers noted, “There was a general sense that what was being built wasn’t up to snuff, [but they] were basically saying there is a budget cap and we are going to build what we can with that.”

That pretty well sums it up.  The people responsible for these matters decided that sufficient resources would not be devoted to the New Orleans levees.

We now know the consequences of that decision.


“Report Examines Path to Failed New Orleans Levees”

“Why New Orleans Levees Failed”