Almost forgotten in the troubles of New Orleans east of the Mississippi River is the other part of the city — across the river. That part of town is also protected from the river by a levee, but it's rapidly losing its natural barrier from storm surges from the Gulf of Mexico to the south: the coastal marshlands.

Ironically, it's the river levee itself, built in the 1930s, that has caused the problem, says Robert Twilley, a professor of wetlands biogeochemistry at LSU.

Before the levee, the river periodically flooded over the southern marshlands, depositing silt that built up the land there, keeping it ahead of the ongoing subsidence of the river delta into the Gulf of Mexico.

For more than 70 years now there have been no floods and no silt, and the marshlands are steadily sinking, he says.

To halt that trend, Twilley says, engineers, biologists and geologists are working together — instead of knocking heads, which has been the case for decades.

"Post-Katrina, it's really all going to be one," said Twilley of the efforts to protect New Orleans and the entire Louisiana coast.

Of course, none of these projects will change the geological fact that New Orleans is still sinking. Some estimates have put Louisiana's loss of land at 35 square miles every year.

But they will buy something that's been in short supply along Louisiana's Gulf Coast: the hope that someday another Katrina won't be able to wreak so much havoc.