TCS Daily

The City Below Sea Level

By Jackson Kuhl - September 3, 2005 12:00 AM

The founding of New Orleans owes much to the conniving not of a Frenchman, but of a Scotsman.

John Law was a professional gambler who fled Great Britain after killing a man in a duel. After wandering the Continent, he eventually became the confidant of Philippe, the Duke of Orleans and regent of France. Their shared interests -- women and games of chance -- led to the creation of a get-rich-quick scheme that historians today call "the Mississippi Bubble."


Law's plan was to convince nobles and wealthy merchants to purchase shares of stock in land in Louisiana, which had been claimed for France in 1682 by explorer Robert Cavelier de LaSalle. Then, in return for a plot of their own and free passage, volunteers (read: shanghaied paupers, criminals, and prostitutes) would be enlisted to emigrate to the New World and work the shareholders' land. The 18th-century venture capitalists would see returns on their investment once troves of gold, silver, diamonds, and pearls were discovered -- which, Law insisted, could be found under every cypress knee and in every duckweed-scummed pool of the Mississippi delta.


Law was contracted in 1716 by the French government (read: Philippe) to establish a new bank which would extend him endless credit for his company.


The charter also granted his company control of Louisiana. Law reappointed Jean Baptiste LeMoyne, Sieur de Bienville, to a second term as governor of Louisiana. Bienville had been eager to found a trading post at the foot of a Native American portage along the Mississippi which connected the river to a bayou, and hence to Lake Pontchartrain, in the north. He saw this as his chance. Law and the royal engineer both thought Bienville's choice was ridiculous -- the site was in the middle of a swamp. The small patch of dry ground lay at a curve in the river, Bienville argued, halfway between Fort Rosalie (Natchez) along the Mississippi and Fort Louis at Mobile. Also, he said, it would be safe from hurricanes. Being the highest-ranking official on-site, Bienville had his way, and Nouvelle Orleans -- named after Law's benefactor -- was born in 1718. Not that it mattered for John Law: by the end of 1720, he was bankrupt and had fled Paris for Belgium.


Engineers today would argue with Bienville's choice of site, too.


According to Rick McCulloh, research associate with the Louisiana Geological Survey at Louisiana State University, modern New Orleans is sinking for a number of reasons.


"If you have a wetland soil, it has a very high clay content and a high content of organic matter," said McCulloh. Much of New Orleans outside of the Vieux Carr -- the French Quarter that was Bienville's original city -- has been built on swampland drained by pumps and canals. Water seeping from the clay into the canals, which is then pumped uphill into Lake Pontchartrain, leads to volume reduction in the soil. It compacts down.


"The other issue is oxidation of organic matter," said McCulloh. "The sediment in a wetland is in a sort of pickled state -- it's prevented from exposure to oxygen. As soon as you dewater the soil, atmospheric oxygen then invades that top part of the soil column which was not previously exposed." The resulting decay of organic material can have a tremendous effect on the volume.


Of course, the leveeing of New Orleans from both lake and river prevents fresh sediment from accumulating and restoring height lost to volume reduction in the clay.


But, McCulloh said, while clay dehydration can occur at deeper levels too, these issues are mainly just on the surface where people are active. "The biggest process of all is the one in which the entire coastal zone is warped across a hinge zone by the deposition of sediment in the Gulf."


The Mississippi River washes incredible amounts of sediment downriver and dumps it in the Gulf of Mexico at the shelf between shallow and deep water. The weight of this huge lobe of sediment is such that it can actually create ripples which lift other parts of the landscape. Like a seesaw, when one end sinks down, the other end of the board rises. Great news if you are on the "updip" side of the seesaw's fulcrum -- but bad news if you are on the sinking side. And New Orleans, McCulloh believes, is on the wrong side of the hinge zone.


Just as geologists scratch their heads over Bienville's real-estate acumen, in turn Bienville might share the frustration of NOLA mayor Ray Nagin with this week's relief efforts. "We are working at Nouvelle Orleans with as much zeal as the shortage of men will permit," Bienville wrote in 1718 about the city's construction. "I am grieved to see so few people engaged in a task which requires at least a hundred times the number."


For more coverage of Hurricane Katrina and its aftermath, and to learn how you can help the victims of this disaster, please visit our special section Tragedy on the Gulf Coast. 


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