New Orleans, Katrina and the Army Corps of Engineers

Images of a flooded New Orleans following Hurricane Katrina Levee breaches
(photo: Dallas Morning News)

It’s well understood that the city of New Orleans is situated between two bodies of water, a river and a lake, and that much of the city lies below sea level. When hurricane Katrina hit the city, levees broke and the city was flooded. I (Keith) am frequently asked, why would anyone build a city in such a location in the first place, and more pointedly, why should the American taxpayer pay to rebuild it. If I have the time to explain and the audience is open to it, here’s my reaction. First some history...

The Mississippi River since the last ice age had for centuries, that is until recent years, created natural "levees," sometimes hundreds of yards wide, as periodic flooding deposited river-born silt along its banks. These elevated areas became the location for early settlements along the river with New Orleans, founded in 1718, being a good example.

Early maps of the city show its development along the high ground of the Mississippi. The maps also show that between this early city and Lake Pontchartrain were several square miles of wetlands. Over the decades as the city expanded as a major sea port, there was no way to expand except northward into these wetlands in the direction of the lake. To do this the wetlands were gradually drained over the decades by canals that flowed in to Lake Pontchartrain. And today that’s how the city and much of the metropolitan area is kept dry-- by a series of drainage, or outflow, canals that empty into the lake. The drainage is facilitated by massive pumping stations located inland from the lake.

There is another type of canal that alters the New Orleans landscape, the Industrial Canal, a waterway that was dredged in the 1920's as a link between Lake Pontchartrain and the Mississippi River. (Lake Pontchartrain is not truly a "lake" but a brackish, inland bay that’s connected to the Gulf of Mexico through Lake Borgne, another "lake.") More recently, in the 1960's, the U.S. Army Corps of Engineers dug a canal that connects Lake Borgne and the Industrial Canal to shorten the distance for ships going up river by about 100 miles. This is the Mississippi River-Gulf Outlet canal, referred to not-so-affectionately as "MR-GO."

Along both types of canals, the outflow canals and the Industrial Canal, the Army Corps of Engineers, has constructed a levee system to protect the city from flooding. Since 1927 when Congress charged the Army Corps with the responsibility of protecting life and property along America’s waterways, this organization has designed and constructed thousands of miles of levees and floodwalls to do just that. The New Orleans area has 350 miles of the Corps’ levees.

When Hurricane Katrina struck it actually sideswiped the city of New Orleans as it headed to the east toward the Mississippi Gulf Coast. As the storm passed over Lake Pontchartrain, however, its high winds pushed a surge of water backward up two of the major outflow canals with such volume and force that the levee system failed. Eighty percent of the city was flooded. A surge of water was also pushed up the MR-GO into the Industrial Canal where the levees protecting the upper and lower Ninth wards failed.

The Corps’ levees consisted of two parts, the levee itself which is mounded up soil and a flood wall made of concrete that sits on top of the levee. In some of the levees steel pilings are driven into the levees to support the flood walls. In the case of the Industrial Canal, the flood walls were overtopped by the surge so that the soil behind was scoured so badly the walls simply collapsed.
Subsequent investigations by both the Corps and an independent team of experts (see the Team Louisiana website http://www.publichealth.hurricane.lsu.edu/TeamLA.htm) showed that the levees along the outflow canals were poorly designed, built on sandy and porous soils with pilings that weren’t nearly deep enough and that they failed to meet minium safety standards. They were not overtopped, but rather just collapsed as a result of poor engineering. (See the photos of the 17th Street canal and the London Avenue canal levees.) The disaster that hit this city in August, 2005 was a man-made disaster, not a natural disaster.

Team Louisiana researchers discuss forensic developments at a section of the 17th Street Canal breach (photo: Team LA 2005)


Damage to the London Avenue Canal at Robert E. Lee, Hurricane Katrina (photo: Team LA 05)

As mentioned, by a long standing act of Congress, protecting life and property against flooding along the nation’s waterways is a Federal responsibility. The national government failed to protect New Orleans and has, in my opinion, an obligation to rebuild the levee system so that it won’t fail in future storms. And there is an additional obligation–in the form of direct compensation–to help this city rebuild.

(Bev and I both would like to recommend a book that discusses the impact of Katrina on the city and the failure of the Army Corps of Engineers to do its job of protecting the city. See Jed Horne’s Breach of Faith, Random House, 2006.)