Looking into the future the Pelican feeding its young from a self-induced wound in its own breast (as depicted, mysteriously, on the state flag of Louisiana) is accepted as an appropriate symbol of both self-sacrifice and rebirth. Through his selfless efforts, man is raised from the slavery of ignorance to the condition of freedom conferred by wisdom. Given the current state of affairs in Louisiana, one hopes that the understanding of the Pelican as a symbol shall point the way towards a new consciousness of ourselves as a whole, and lead us to face our futures with strength, grace, wisdom and faith, to learn from our mistakes and carry our successes and zest for living to future generations.

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17th St. Canal Levee Sheet Metal Pilings 7 ft. Shallower than Corps Claimed

Nov. 10, 2005
By Bob Marshall
Staff writer
Source: http://www.nola.com/

Sheet piling supporting the failed floodwall on the 17th Street Canal extends just 10 feet below sea level, 7 feet shorter than the Corps of Engineers has maintained, a team of investigators said Wednesday, strengthening earlier findings that faulty design and construction played a role in the canal breaches that flooded much of New Orleans during Hurricane Katrina.

An LSU forensic engineering team, working in conjunction with the state attorney general's office, began examining the levee foundation with ground sonar Wednesday. The first reading was taken about 150 yards south of the break that allowed water from Lake Pontchartrain to inundate the city.

Independent engineers have questioned whether the pilings, even at the corps' stated depth, went down far enough to support the floodwalls and prevent storm surge from penetrating beneath the earthen levees and causing structural failure.

Corps officials declined specific comment on the LSU team's initial sonar readings Wednesday.

"The various engineering teams are reviewing information, and the corps will wait until the teams come out with their final report before commenting," corps spokesman Tim Dugan said. "The corps is not ready to speculate."

Ivor van Heerden, director of the Louisiana State University Hurricane Center and leader of the forensic team, said the group would take about a dozen more readings as it works its way to the edge of the 17th Street Canal breach. The equipment being used can determine the type of soils beneath the floodwall as well as the length of the pilings. He said the team would take similar readings at the London Avenue and Industrial Canal levees, which also failed in the storm.

'Anchored in peat'

Sheet piling -- long, narrow, interlocking sections of solid iron -- often are used to reinforce earthen levees. In the porous, structurally weak soils that are found in the former swampland much of New Orleans was built on, engineers say the longer the pilings, the stronger the wall and the levee.

The New Orleans levees that failed had floodwalls of concrete that sat atop sheet piling walls driven below the tops of the levees. The corps designed and supervised the construction of the floodwalls.

A number of engineering teams investigating the failures said the 17-foot depth of the piles stated by the corps were a critical part of the failure because they did not extend beneath the bottom of the canal, which the corps said was 18.5 feet deep. Water from the canal could quickly move through the porous soils, the engineers said, rapidly reducing the support provided the floodwall and leading to the collapses.

Soil borings the corps consulted as it designed the walls in the early 1990s indicated pilings would have to be driven at least 40 to 50 feet deep before reaching soil strong enough to support the wall, investigators have said.

"By going down just 10 feet, the piles are anchored in peat, the weakest layer of all the soils below the levee and the canal," van Heerden said.

A copy of the final review set of design drawings for the project obtained by The Times-Picayune showed the pilings on the New Orleans side of the canal were to be driven 10 feet below sea level, while those on the Jefferson Parish side were 6 feet below sea level. But the corps has said the piles were actually driven to 17 feet below sea level before the concrete caps were added.

Fred Young, a structural engineer with the corps, told a meeting of the Orleans Parish Levee Board on Wednesday that pilings at the breach had been 17 feet below sea level. Young said the corps is replacing that section of the floodwall with pilings that will be driven 51 feet below sea level.

Who is responsible?

Because the corps has refused to release final design drawings and other documents, researchers have been trying to solve what they call "the mystery of the sheet piles." But even with the sonar measurements, it still is unclear which government entity is responsible for the pilings.

Newspaper reports from the period show the Orleans Levee Board first used sheet piles on the canal after the 1947 flood. After Hurricane Betsy slammed the city in 1965, the board drove 18-foot pilings to raise the canal floodwalls to 9.4 feet above sea level.

But according to the engineering section of the Orleans board, in 1988 those pilings were pulled as part of work done by the New Orleans Sewerage & Water Board, and new pilings were driven. The length of those piles is not a part of the public record, and the Sewerage & Water Board did not answer requests for details on that work.

"The corps keeps saying the piles were 17 feet, but their own drawings show them to be 10," van Heerden said. "This is the first time anyone has been able to get a firm fix on what's really down there.

"And, so far, it's just 10 feet. Not nearly deep enough."