Even putting conspiracy theories about dynamite aside, there have been more explanations in the last three years for the failure of the New Orleans levees during Katrina than there have been task forces assigned to the issue – and that’s saying a lot. Evidently, the problem is:
- Water shifting the ground under the levees
- Lack of government oversight in construction
- Poor maintenance
- Loss of the wetlands
- The Industrial Canal
- New Orleans sinking three inches a decade
- Unforeseen hydrostatic pressure
- Hordes of nutria tunneling away
Feeling Forgotten by America
While Katrina remains simply “the storm” here in New Orleans, it feels at times that the rest of the country is tired of hearing about our problems. A bright moment did happen on January 20th, 2009.
If you blinked, you might have missed it, but President Obama mentioned us in his inauguration speech:
"It is the kindness to take in a stranger when the levees break, the selflessness of workers who would rather cut their hours than see a friend lose their job, which sees us through our darkest hours.”
So, OK. Evidently we’re still on the political map. It’s been over three years now since Katrina. What state are the levees in these days?
Money, New Orleans Levees, Red Tape, and More Money
Levees are incredibly expensive, and with great money comes great bureaucratic bickering. The Army Corps of Engineers spent $25 million just assessing the state of the levees after Katrina, then challenged parishes that tried to use that data to figure out how bad things actually were.
On January 15, 2009, Governor Bobby Jindal showed up at Houma to announce with great pride that $195 million in state and local money had been allocated for Morganza-to-the-Gulf, a system of levees, floodgates, and a lock to protect Terrebonne and parts of western Lafourche.
On the same day, the Corps of Engineers announced that getting Morganza to full hurricane strength would take $2.5-$8.5 billion and 20 to 30 years.
I’m guessing that $195 million might be enough to do a good survey.
Why Levees Are Hard to Build
It’s tempting to think of levees as walls or the sides of a swimming pool. In fact, they are dams. To succeed in holding back the waters, they must be able to deal with the damages of water erosion and ground movement and adjust to great variations in water pressure. In short, they keep the forces of nature in check.
Just to use something familiar, compare the length of the Hoover Dam, 1,244 feet, to the length of the levees surrounding New Orleans and neighboring parishes: 325 miles.
So yes, sometimes all you need for a levee is a nice pile of dirt – but then a hurricane comes along, or a massive flood, and the comparison to Hoover Dam suddenly seems more appropriate.
Levees are useful every day. But we don’t usually build them for the status quo. We build them to hold off disaster.
What Is a Levee?
New Orleans’ levees are structures made of clay in cross sections forming a truncated triangle. (Some levees are made of sand or silt, but the sedimentary particles of clay are smaller in diameter.) The levee’s base is usually 10 times as wide as the height of the levee.
Floodwalls are walls of steel and concrete. They can be used instead of a levee, or put on top of levees.
What’s Been Done So Far
The very first order of business after the 2005 storm, of course, was bureaucratic. Pre-K, there were about a dozen agencies overseeing the levees. An amendment to Louisiana's constitution replaced them with two levee boards, one on each side of the Mississippi.
This has allowed the Corps of Engineers much greater efficiency to accomplish quite a few upgrades on the levee system since Katrina.
- About $2 billion has been spent on structural upgrades: 220 miles of repaired, raised, and replaced levees and floodwalls, 17 new pump stations, and improved flood resistance in existing pump stations.
- A particular improvement was made in making the levees less vulnerable to “over-topping.” Wherever feasible, the Corps of Engineers replaced "I-walls" (concrete barriers anchored to the levee by a steel sheet pile-driven into the ground) with "T-walls," which are rooted into a concrete base and anchored by multiple steel beams.
- The Corps also built floodgates to seal off three drainage canals from Lake Pontchartrain and installed pumps along the canals strong enough to suck out an Olympic pool in a few seconds.
Of course, no one believes these improvements are enough.
The New Orleans Levees During Gustav
Probably the most encouraging event – whether it deserves the title or not – was the strength of the levees during Gustav.
When we came back to town after Katrina, especially in those first few months when the traffic on the streets was made mostly of military jeeps and garbage trucks, New Orleans felt so fragile. The next hurricane season, it seemed all it would take was a good-sized thunderstorm for the city would to be swallowed up once again.
So while Gustav created its own tragedies in 2008, its upside was at least a partial test of the levee system – a test New Orleans passed.
The best video of the storm was water from the Industrial Canal lapping against the top of the floodwalls. Some did make it out to drain into the adjoining neighborhood of Gentilly Woods. But the floodwall held, and plans have been made to raise it.
Future Plans for New Orleans Levees
The Corps has gotten about $14 billion for future levee upgrades. These include:
- Protecting against storm surge by closing “Mr. Go” with a two-mile-long barrier at the confluence of Mr. Go and the Gulf Intracoastal Waterway.
- Constructing a barrier where the Industrial Canal meets Lake Pontchartrain.
- Raising other levee sites.
Now then, a lot people hold the opinion that the Corps needs more fixing than the levees do, but there’s not too much New Orleans can do about that.
Are you listening, President Obama?