Design flaws behind New Orleans levee failures

["Richard M. Smith" <rms () computerbytesman com>]

http://www.nola.com/news/t-p/frontpage/index.ssf?/base/news-4/11359258922999
60.xml

Corps never pursued design doubts

Higher-ups raised red flag, then dropped it 
Friday, December 30, 2005 
By Bob Marshall
Staff writer 

The engineering mistakes that led to the canal levee failures that flooded
most of New Orleans during Hurricane Katrina were found and then dismissed
in the Army Corps of Engineers' design review process in 1990, an
investigative team reviewing the failures says. 

Documents, obtained by The Times-Picayune and provided to forensic engineers
studying the levee breaches, show project engineers made a critical mistake
in assessing soil strengths on the 17th Avenue Canal project, said Robert
Bea, a University of California-Berkeley professor who is a member of the
National Science Foundation team. 

Corps documents show the mistake of overly optimistic levee strength was
detected by its Vicksburg, Miss., office, which directed local engineers to
make changes. But when the chief engineer in New Orleans replied that the
results were based on "engineering judgment," his superiors dropped the
issue. 

Bea said the discussion in the 16-year-old "design memo" points to the key
decision that created fatal problems on the 17th Street Canal levee and
could reveal a systemic problem that will show up during investigation into
the London Avenue and Industrial Canal levees, which also breached during
the Aug. 29 storm. 

"From all the data we have, from all the documents made available to us,
that exchange highlights where the key mistake was made in the design
process, and how it was allowed to stand," Bea said this week. 

"The design engineers didn't account for the weak layers in that swamp, and
the Vicksburg office picks that up in review. But the New Orleans office
says it's our professional judgment this is OK. In our business, that's an
acceptable answer. But it's an answer Vicksburg can disagree with -- but it
didn't. 

"And from the documents we have, the issue is never raised again. At least
not until Katrina comes along." 
...
_______________________________________________
Fun and Misc security discussion for OT posts.
https://linuxbox.org/cgi-bin/mailman/listinfo/funsec
Note: funsec is a public and open mailing list.