New Orleans' Levees

New Orleans' Levees

This article relates to Five Days at Memorial

Though Hurricane Katrina did strike a mighty blow, it was only part of the catastrophe that befell New Orleans. As Sheri Fink writes in Five Days at Memorial, "Katrina rapidly lost strength after moving onto land. The rain lessened and the winds began to ease by late morning. The water level outside Memorial stabilized at about three feet."

During the squalls of the hurricane on Monday August 29, 2005, water raced down Clara Street (Memorial's location) and "a red car and a red van were submerged to the tops of their wheel wells," but the hospital seemed free from disaster. Then a National Guard soldier informed Memorial's plant operations director that the levees had been breached. Fifteen feet of water from Lake Pontchartrain was heading for the hospital.

According to NPR reporter John F. Burnett, in his book Uncivilized Beasts and Shameless Hellions: Travels with an NPR Correspondent (2006), New Orleans was founded in 1718, built on "alluvial silt next to the Mississippi, 4.4 feet above sea level," a natural levee. Neighborhoods in the growing city of New Orleans moved closer and closer to Lake Ponchartrain. "Over the decades, the land, some of which is lower than the floor of the lake, was drained and reclaimed by digging a network of drainage canals and installing huge steam-driven paddlewheels to push the periodic floodwaters [back] into the lake," Burnett writes. "Gradually, the bog became habitable." From 1717 to 1727, the French built the first levee system near the area, but it was no match for heavy flooding.

The first man-made levee system in New Orleans was built by 1727. But Mississippi River floods and late-summer hurricanes still caused serious floods in the city. "Levee breaches were common in the early days," observed Mark Twain in 1883, "There is nothing but that frail breastwork of earth between the people and destruction."

Burnett asserts that storm surges that originate in Lake Ponchartrain and rush into the city are responsible for flooding. He writes, "The brackish, oval-shaped lake is huge, at 630 square miles, and shallow, with an average depth of only 13 feet, making it particularly susceptible to flooding. A major hurricane bearing down on New Orleans would push a mass of water before it, and the hydraulics of southeastern Louisiana would provide multiple portals into the lake - which is exactly what happened on August 29."

The 2013 Report Card for America's Infrastructure, issued by the American Society of Civil Engineers, gave the "nation's estimated 100,000 miles of levees" in "all 50 states and the District of Columbia" a D+, a poor grade. The report states that "significant federal funding" has gone to New Orleans for its levee system. But according to a January article in New Orleans' The Times-Picayune newspaper by reporter Mark Schleifstein, a consulting engineer for the Southeast Louisiana Flood Protection Authority-East named Bob Jacobsen says that the new design standards used to improve the levee system in the wake of Katrina "are already outdated." A more recent article by Schliefstein from the end of May, providing a fuller picture of the new levee system, says that the "improved system is designed to block overtopping from surges created by a hurricane with a one percent change of occurring in any year, the so-called hundred-year storm. The improved levee design is supposed to guarantee that even when topped, the levees and floodwalls will stay in place."

Yet, emergency managers warn that "the levee system is designed to protect property, not lives, and hurricanes with surges greater than the system's hundred-year storm design will top the new levee system for at least a few hours." According to Lt. Col. Jerry Sneed, deputy mayor for public safety in New Orleans, his biggest worry is that people will think that the levee system is good enough now and they won't have to evacuate. But calls for evacuation are still at the top of the list when a hurricane approaches.

The levees have been breached again and again, and attempts to strengthen them and the push for more safety during storms still go on. Unfortunately, the only true test is when a major storm hits.

Both images from Wikipedia. The first image of Lake Pontchartrain. The city of New Orleans is on the southern shore below the lake. The Lake Pontchartrain causeway can clearly be seen bisecting the lake. To the upper left is Lake Maurepas. The city of Slidell, Louisiana can be seen at the top right of the photo.
Second image depicts windspeed of Hurricane Katrina 7 a.m., showing hurricane-force winds (yellow/brown/red: 75-92 mph) hitting the northeast/south shores of Lake Pontchartrain (1 hour after landfall) on August 29, 2005.

Filed under People, Eras & Events

This "beyond the book article" relates to Five Days at Memorial. It originally ran in September 2013 and has been updated for the January 2016 paperback edition. Go to magazine.

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