Sheets of concrete were cut from a levee wall Monday as the Army Corps of Engineers investigated the failure of the city’s flood-protection system during Hurricane Katrina.
The work along the city’s 17th Street Canal was part of a two-day project to see whether actual pieces of the wall matched up with drawings of how the structure was supposed to be built.
Both the Corps and a team of independent engineers from Louisiana State University have used sonar to see how deep into the ground contractors drove steel sheet pilings, which act as an anchor for the concrete flood wall atop the levee.
Plans on file with the Corps indicated the sheet pilings were supposed to be 17 feet below sea level, but sonar testing showed the pilings went only to 10 feet.
Engineers have said driving sheet piling to that depth — still nearly 8 feet higher than the canal bottom — left the levee vulnerable by allowing canal water to seep beneath the pilings to the dry side of the wall. That process eventually caused the flood wall to collapse.
More answers to come
Amid a backdrop of flood-wrecked homes, the Corps first cut samples from the concrete wall. Workers then broke up the bottom of the wall to expose the steel sheet piling. The piling was to be pulled from the ground on Tuesday, a process that could provide undeniable proof that it was shorter than plans called for.
“A lot of questions will be asked if it comes out to be below the design specifications,” said Corps of Engineers Col. Lewis Setliff, the man in charge of rebuilding the hundreds of miles of levees ringing the New Orleans area.
Breaches at both the 17th Street and London Avenue canals allowed flood water to inundate large areas of the city from close to Lake Pontchartrain to the edge of downtown.
Those areas — which included several universities and thousands of homes and businesses — likely would have been spared widespread flooding if the levees had held up against pressure from water that rose above normal levels but did not flow over the top of the flood walls.
Army engineers intend not only to measure the sheet pilings but also to test the concrete and reinforcing steel bar used in the flood wall to make sure they were of the proper strength, Setliff said.
The state attorney general, the Orleans Parish district attorney and the U.S. attorney all have launched investigations aimed at finding any wrongdoing in levee construction and maintenance.
Residents suing after homes destroyed
Among the curious onlookers at the work site Monday was attorney Joseph Bruno, who has filed a class action lawsuit seeking financial relief for those left homeless by flooding caused by levee breaches.
The lawsuit names as defendants both the Corps of Engineers and contractors the Corps hired to work on the 17th Street and London Avenue flood walls.
The Corps cannot be sued for flood damage, but Bruno said his lawsuit may get around that because it asks for relief on the basis that the federal government promised New Orleans residents and businesses a level of flood protection that never existed because of apparent design and construction flaws.
In Baton Rouge, Gov. Kathleen Blanco announced her support over the weekend for consolidating southeast Louisiana levee districts in an effort to reform the agencies that have long been criticized as dens of political patronage.
The proposal had attracted broad support from business groups and others involved in the rebuilding effort who said consolidating the boards would help coordinate hurricane protection.