From: John Cuccia 

On Sat, 04 Mar 2006 16:08:27 -0500, "Gary Wiltshire"
 wrote:

>> No, it has been determined that the levees and floodwalls were built
>> as designed.   In the case of the levees to the east, the storm
>> exceeded design conditions.  In the case of the floodwalls to the west
>> it did not but their design was faulty, not their construction.
>
>What I've read indicates bad assumptions about the subsurface conditions
>supporting the levies.

It wasn't a bad assumption, the designers were all experienced and knew
what the were dealing with.

It appears that a transcription error occurred when data was transferred
from soil boring logs to cross-sectional views of the area.  Here's an
excerpt from a longer article that I quoted in full in another message in
this thread.  It's from the New Orleans Times-Picayune:

========================
A cross-section drawing in the project design documents shows a weak layer
of peaty soils between 11 feet and 16 feet below sea level in the area that
failed during the storm. But information in the individual soil borings
that were used to draw the cross section show the peaty layer extending as
deep as 30 feet below sea level.

Investigators said their own borings taken at the site this week confirm
the 30-foot depth, leading them to believe that designers used the flawed
cross-section drawing to set the sheet pilings beneath the floodwalls at
17.5 feet below sea level -- a choice that allowed water to migrate to the
land side of the wall, causing the breach.
=======================

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