custom ad
NewsFebruary 25, 2003

NEW ORLEANS -- The high wooden porch slants toward the street. The twin steps are cracked. So is the plastered support between them. "My wife and I, we'll lie in bed and notice a new crack every couple weeks," said Stalios C. Leres, who rents one side of the aging two-family house...

By Janet McConnaughey, The Associated Press

NEW ORLEANS -- The high wooden porch slants toward the street. The twin steps are cracked. So is the plastered support between them.

"My wife and I, we'll lie in bed and notice a new crack every couple weeks," said Stalios C. Leres, who rents one side of the aging two-family house.

Southern Louisiana is sinking -- houses, cemeteries, roads and all.

While most of North America rests on bedrock, New Orleans and the surrounding area are built on Mississippi River silt. And the silt is slowly settling and compacting because of gravity.

The settling has been going on for ages, but the surface really began dropping fast during the 20th century because of man's doing: The levees built to keep the Mississippi within its banks all but stopped the floods that used to lay down new layers of soil over the land.

Moreover, the human effects of the sinking are greater than ever simply because more people are living here.

Houses not built on deep pilings are tipping and cracking. So are streets, often rupturing water mains and sewer lines beneath them. Along parts of the coast, the ground is now under water, and some yards have become marshland.

The situation is so dire that some highways may be unable to serve as evacuation routes while a hurricane is approaching, the National Geodetic Survey has warned. The roads themselves could be awash.

'Mudjacking'

For lack of any better solution, houses have to be jacked up and stabilized one at a time. Some house levelers use a technique called "mudjacking" -- drilling holes in the foundation, then pumping in a mixture of mud and cement under pressure to raise and level part of a building.

The sinking has run anywhere from 6 to 20 inches over the past 20 years, said Roy Dokka, a professor at Louisiana State University's Center for Geoinformatics. University of New Orleans geologist Shea Penland disputed that, saying those figures apply only to the highways where the measurements were taken. The marshlands are sinking much more slowly, he said.

Receive Daily Headlines FREESign up today!

Whatever the case, there is "a huge trend of sinking throughout Louisiana, making it the hotspot of the country in terms of this kind of phenomenon," said geologist Stephen Leatherman of Florida International University.

Part of the problem is that silt is even finer than sand and compresses more easily.

In southern Louisiana, pilings often must be sunk 30 feet or more to get to sand dense enough to stabilize the buildings they bear. In Metairie and Kenner, just west of the city, a large building might need pilings up to 100 feet deep.

In Leeville, 60 miles southwest of New Orleans, the land has sunk 14 inches over the past 20 years. At Leeville's old cemetery, brick mausoleums that were on land back then are now under water.

Compounded by dry spells

The sinking in Louisiana is compounded by dry spells, which cause soil at the surface to shrink like a sponge left on a kitchen counter. Some say the settling is also worsened by drainage projects that lower the underground water level.

At the NASA Michoud Assembly Facility -- the Lockheed-Martin-operated plant in New Orleans where the fuel tanks that have come under suspicion in the space shuttle Columbia disaster are made -- the buildings are on pilings, but settling still causes occasional plumbing problems.

"Every now and then, we'll have an underground piping problem, like a water leak," plant spokesman Harry Wadsworth said. "It's a recurring nagging headache kind of thing. Nothing dramatic -- just that recurring maintenance."

------

On the Net

Loyola University Center for Environmental Communications: www.loyno.edu/lucec/mrdliving.html

Story Tags
Advertisement

Connect with the Southeast Missourian Newsroom:

For corrections to this story or other insights for the editor, click here. To submit a letter to the editor, click here. To learn about the Southeast Missourian’s AI Policy, click here.

Advertisement
Receive Daily Headlines FREESign up today!