Questions Surround Rebuilding of N.O. Levees

Even though Hurricane Katrina (search) exposed the weakness of the levee system around New Orleans, officials won't rebuild the barriers higher and better — at least not right away.

Col. Lewis Setliff, the engineer overseeing the levee repairs for the U.S. Army Corps of Engineers (search), said the Corps only has the authority to rebuild levees to the strength they were prior to the storms that damaged them.

The levees that broke were built to withstand Category 3 hurricanes, which have winds up to 130 mph. Hurricane Katrina's winds were about 145 mph — a Category 4 — when the storm hit Louisiana.

Without approval from Congress, the Army engineers cannot build the levees higher and stronger. And even if Congress were to give that approval soon, it would come too late to allow them to be finished by the time the 2006 hurricane season begins in June.

"We've got eight months and counting," Setliff said. He added, though, that the levee system in its broken and heavily eroded state might not do much to stop flooding should the area get hit again before the current hurricane season ends in a month.

Setliff said about 10 percent of the New Orleans-area levee system was damaged, mostly because of water running over the tops of the barriers. To repair those levees, crews must first pack down what is left of them, filling in holes scoured out by water. Dirt will then be added to get them back to their original height.

The levee break that remains a mystery is along the 17th Street Canal (search), which badly flooded New Orleans' Lake View and Mid City neighborhoods. The Corps had eyewitness reports of water topping the levee there, but Walter Baumy, chief of engineering for the New Orleans district, said the break could have occurred from water pushing through the bottom of the levee, rendering the flood wall unstable.

Bringing just the area of New Orleans along the Lake Pontchartrain (search) shoreline up to Category 4 or 5 protection would cost $2.5 billion to $3 billion, according to the Corps.

If the Corps gets approval to build higher levees, engineers could in some cases build on top of what is already there. In other cases, the Corps might choose to dig up some of the current work and rebuild using fabric reinforcements that would allow levees to climb higher without taking up more room.

"We would look at it from an economic and engineering standpoint — does it make sense to degrade the levee in some places?" Baumy said. "There may be areas you would take that route, but that's for another day. In eight to nine months you cannot build Category 5 protection. You're talking years."