Ground Shifted Beneath Levees

By Ralph Vartabedian Times Staff Writer
Sat Oct 1, 7:55 AM ET

The rapid sinking of the Louisiana coast may have lowered New Orleans levees and contributed to their failure after Hurricane Katrina, resulting in the city's catastrophic flooding, engineers and other experts say.

Levees and storm walls may be as much as 2 feet lower than they were designed to be, both because elevation data were outdated when the levees were built and because the land has continued to sink, they say.

Experts had sounded alarms in recent years about subsidence, as the sinking is known, warning that the coast was far more vulnerable than most people realized. Federal officials and levee managers say they will begin reviewing the problem in coming weeks.

Subsidence is one of several factors experts are scrutinizing to determine why three levees failed, leaving 80% of the city underwater and hundreds dead.