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<DIV style="MARGIN-LEFT: 1em; MARGIN-RIGHT: 1em"><A
href="http://www.latimes.com/news/nationworld/nation/la-na-levee2jun02,0,3385244.story?track=tothtml">http://www.latimes.com/news/nationworld/nation/la-na-levee2jun02,0,3385244.story?track=tothtml</A><BR>
<DIV class=body><I>From the Los Angeles Times</I></DIV>
<H1>Army Corps Admits Design Flaws in New Orleans Levees</H1>
<DIV class=storysubhead>Its report says the defects were to blame for most of
the flooding and damage from Katrina.</DIV>By Ralph Vartabedian<BR>Times Staff
Writer<BR><BR>June 2, 2006<BR><BR>NEW ORLEANS — The Army Corps of Engineers
acknowledged Thursday that design defects in the levees protecting New Orleans
caused the majority of flooding during Hurricane Katrina and that the disaster
would almost certainly trigger reforms in how the federal government protected
the American public.<BR><BR>The corps said its 40-year effort to construct a
hurricane protection system for southern Louisiana had resulted in a set of
piecemeal projects that "was a system in name only," a recognition that a wide
range of errors, weak links and incomplete construction was at the heart of the
massive damage that occurred Aug. 29.<BR><BR>The corps released a 6,000-page
report written in the couched language of government engineers but which
delivered a stunning set of findings about errors made in the design of storm
walls and earthen levees that failed during Katrina.<BR><BR>The report found
that four major breaches of I-walls, a type of concrete storm wall that sits on
an earthen levee, caused 65% of the flooding in the New Orleans
area.<BR><BR>Although the report's summary never uses the words "design defect,"
corps officials said they now accepted that their work had shortcomings and
errors that were responsible, in large part, for the damage.<BR><BR>"We do take
accountability," Lt. Gen. Carl Strock, commander and chief engineer of the
corps, said at a news conference, where he was joined by five Army generals, the
federal coordinator for Gulf Coast reconstruction and an assistant Army
secretary.<BR><BR>The corps, Strock said, "is deeply saddened and enormously
troubled" by the disaster.<BR><BR>Strock said the remaining I-walls would
eventually have to be replaced because they proved ineffective during Katrina.
The primary breaches at the 17th Street, London Avenue and Industrial canals
occurred when storm waters were still several feet below the tops of the walls,
meaning they failed well below the maximum forces they had been designed to
withstand.<BR><BR>The report also puts in the historical record a formal
acknowledgment of the scope of the disaster, which killed 1,293 people in the
New Orleans area.<BR><BR>"The flooding caused a breakdown in New Orleans' social
structure, a loss of cultural heritage and dramatically altered the physical,
economic, political, social and psychological character of the area," it said.
"These impacts are unprecedented in their social consequence and unparalleled in
the modern era of the United States."<BR><BR>Although many of the technical
findings had been released in preliminary studies by the corps, the report
details significant new information:<BR><BR>• Southern Louisiana is
sinking much faster than generally recognized, and levees were at substantially
lower elevations relative to sea level than they were designed to be. In some
cases, levees were 2 1/2 feet below their designed elevations. Moreover, as
other federal agencies recognized the problem in recent years, the corps decided
not to reexamine the issue.<BR><BR>• The city's pumping system, the only
way to remove water from below sea level, was not designed to operate during a
major storm. Because most of the region's pumps were inundated after Katrina,
the corps was forced to use portable equipment that took 53 days to pump out the
city, allowing the flood waters to saturate and destroy
structures.<BR><BR>• Twenty-five percent of all the housing in the region
was destroyed. In New Orleans, the proportion is believed to be higher. The
destruction of homes accounted for 75% of the losses caused by Katrina,
estimated by the corps at more than $20 billion. Outside estimates are much
higher, exceeding $100 billion.<BR><BR>• A computer simulation showed that
if the levees had not failed, the city still would have flooded because 14
inches of rain fell during a 24-hour period, and storm surges went over the
levees. If the levees had held, the flooding would have been about one-third of
what occurred.<BR><BR>Strock said the repaired sections of levees were now the
strongest parts of the system. The repairs were supposed to be completed by June
1, but they are about two months behind schedule. Among ongoing projects is the
installation of new pumps at the mouth of the 17th Street Canal. The enormous
undertaking required heavy construction work on 169 miles of damaged or
destroyed levees.<BR><BR>The report is full of technical language, including
descriptions of design flaws as "overestimation of subsurface strength." Corps
officials said the reason for such language was not to reduce the effect of the
findings, but rather to set a "nonjudgmental tone."<BR><BR>Although the breaches
caused most of the flooding, a significant part of the Katrina damage occurred
because the storm was larger than the system was designed to
withstand.<BR><BR>Although wind speeds had dropped sharply by the time the
hurricane hit New Orleans, its power over the Gulf of Mexico had created the
largest ocean surge to ever hit North America, the report said.<BR><BR>The
surges along the Gulf Coast reached 28 feet, and waves of 14 feet came on top of
the surges, creating a 42-foot wall of water. The ocean level was lifted by a
drastic fall in the barometric pressure, one of the sharpest drops ever recorded
in the region, Strock said.<BR><BR>The same failure mechanism was to blame for
all of the I-wall breaches. As water rose against the walls, it caused them to
tilt away from the canals and open a small gap along the base of the wall. Water
rushed into the gap and cut the levee in half, significantly reducing its
strength.<BR><BR>The water then penetrated deep into the foundation, causing
instability in the case of the 17th Street Canal levee and seepage in the case
of the London Avenue Canal levee. In both places, the water penetrating the
foundation weakened the system so much that the earthen embankment
shifted.<BR><BR>The report said the corps failed to recognize the potential for
this failure. Outside experts, including a team of investigators from UC
Berkeley, said in a report last week that the corps had ignored its own research
that predicted such failures could occur.<BR><BR>In addition, the corps' report
said, its engineers had used erroneous estimates of the soil strength under the
levees. They also used tests that were spaced too far apart and only took
averages of the soil strengths. The averages did not matter because the levees
failed in the weakest layers.<BR><BR>The report does not attempt to explain why
flawed decisions were made. Reed Mosher, a senior geotechnical expert for the
corps and one of the principal investigators, said the biggest ingredient in the
errors was the technology in use at the time the walls were designed.<BR><BR>"We
wouldn't make the same mistakes today," he said.<BR><BR>The UC Berkeley
engineers said the technology and know-how existed to build stronger levees, but
the corps had lost some of its expertise starting in the 1980s as it shifted
emphasis to managing projects and let private engineers do the
design.<BR><BR>Strock said he "would not make apologies" for focusing on project
management and disputed the assertion that the corps had lost its technical
competence. A second investigation led by the University of Maryland is
scheduled to report next month on the institutional and cultural factors within
the corps that may have led to the errors.<BR><BR>The corps' investigation,
known officially as the Interagency Performance Evaluation Task Force, was
conducted by 150 experts and led by University of Maryland engineer Lewis E.
Link. The report unveiled Thursday is a draft; a final version is due in
September.<BR><BR>The findings will trigger significant changes in how the corps
and other government agencies protect the public from storms and floods, Strock
said.<BR><BR>The corps is responsible for 12,000 miles of levees across the U.S.
It will start treating the levees with the same oversight as it does with dams,
which have historically received a higher priority in terms of public
safety.<BR><BR>Maj. Gen. Donald Riley, director of civil works for the corps,
said reforms were also coming in how flood protection systems were designed and
built.<BR><BR>In the future, he said, levees and other flood protection projects
will have greater resiliency, so that even if storm waters overwhelm them, they
will reduce the effects of floods and allow for a faster recovery.<BR><BR>The
corps will abandon its use of an antiquated method of estimating storm forces,
known as the standard project hurricane, Riley said. It was that model that led
the public to incorrectly believe that the New Orleans levees could withstand a
hurricane as powerful as Katrina.<BR><BR>In deciding whether to build levees,
the corps has long used cost benefit analysis that considered the potential loss
of property, not human life or the social value of a city. Now, he said, diverse
factors will be considered when evaluating whether to build levees.<BR><BR>Riley
said the corps also would be adopting a different system to evaluate the risks
and consequences of its systems. Since Katrina, outside experts said the corps
erred in risk analysis of its levees and should have built much larger margins
of safety. Riley said the new system would use modern risk analysis and would
become a national standard.<BR><BR>Strock acknowledged that the corps must prove
to the public that it could provide a higher level of performance.<BR><BR>"For
those who doubt us, words alone will not change minds," he said.<BR><BR>But the
agency has emerged from the disaster as a stronger organization, he
said.<BR><BR>"We are not wringing our hands; we are going to work."
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