Sinking land ultimately reduces effectiveness of levee protection

11:23 AM CDT on Tuesday, April 18, 2006

Ben Lemoine / WWL-TV News Reporter

The Army Corps of Engineers discovered a $4 billion surprise by underestimating the cost of repairing the levees because south Louisiana is sinking. One geologist has said the sinking will continue, especially in New Orleans East, because that part of town rests on a fault line.

Bad roadways have become a common complaint over the years for some New Orleans residents, but to LSU Geologist Dr. Roy Dokka, they’re scientific evidence which demonstrate that the ultimate problem goes much deeper.

Dokka suggests that Louisiana is not only sinking, but was sliding out toward the south, along the edge of a fault line in New Orleans East – namely Michoud.

For the last century, Michoud has sunk up to two inches per year; taking the levees down with it – four feet total since 1960. According to Dokka’s study, New Orleans East has sunk deeper than any other area in the state and at a much faster rate. It’s a phenomenon that contributes to lower levees and protection from storm surge.

Dokka said it’s a simple case of building for now rather than later.

The Army Corps of Engineers, which funded Dokka’s study, said the sinking land accounts for the rising cost of levees, which means there’s no magic number for any category of levee protection, whether it's category-3 this year or category-5 down the road.

The Corps has called the situation “an extraordinary conundrum,” adding that Dokka’s findings would certainly factor into plans for rebuilding the levees.

As for the price, Dokka said it's more like an installment payment as it seems south Louisiana will be paying for levee protection forever.

"Once we build the levees -- that's not enough. We've got to keep thinking about how they're changing and continue to build them up in certain places,” Dokka said.