Each month Richard Campanella explores an aspect of New Orleans’ geography. His Cityscapes column for Nola.com and The Times-Picayune shines a light on structural, often-overlooked or invisible aspects of the city. This month: a flood in 1849. Up until Katrina it was the largest deluge in the city’s history.
Campanella says that disaster 165 years ago had something in common with Katrina.
"It was a levee breach, though we didn't call them levee breaches back then. The word that struck fear into the hearts of Louisianans was 'crevasse,'" Campanella says.
Back then flood protection was local. There was no state or federal levee system. In the spring of 1849 a crevasse opened at Peter Sauvé's sugar plantation, in Jefferson Parish. It was a high water year, Campanella says, and locals were watching the river stages carefully. The opening in Sauvé's levee widened by June to 150 feet long, roughly the size of the smaller levee breach in the Lower 9th Ward.
A plume of water shot out, covered the back swamp, then flowed into the city. Mostly swamp and cane fields flooded. Only about ten percent of the New Orleans population had water in their homes, and it was a few feet, he says. The flood was stopped June 20 through a bucket brigade plugging it with sediment. Some of the water was directed back out of the city through Bayou St. John, and some simply soaked into the ground or evaporated.
The Sauvé Crevasse flood of 1849, Campanella says, could be thought of as the last major deposit of Mississippi River sediment on New Orleans. That delta-building process had been happening for five to seven thousand years. It stopped when the river was put in the jacket of the levee.
Today, flood risk has almost completely transferred from the threat of the Mississippi River to water coming in from the Gulf of Mexico, a problem exacerbated by the lack of sediment being deposited by regular river flooding.