Colonel Lewis F. Setliff III
Commander/District Engineer, St. Louis District
U.S. Army Corps of Engineers
In August of 2005, Hurricane Katrina hit the Gulf Coast and became one of the largest natural disasters in the history of the United States. It resulted in more than 1,800 deaths and more than $150 billion in damages. Katrina’s storm surge measured up to 30 feet along the Mississippi coast, with winds at 127 miles per hour when it made landfall in Louisiana. Nearly 80 percent of New Orleans was under water. In the aftermath of Katrina, Colonel Lewis F. Setliff III of the U.S. Army Corps of Engineers was selected to command Task Force Guardian, the team responsible for restoring New Orleans’ flood and hurricane protection system to its pre-storm levels before the 2006 hurricane season began.
In the following perspective, Colonel Setliff describes the challenges his team — and local contractors — faced in accomplishing their almost impossible goal of providing a measurably stronger level of protection to the city of New Orleans in a compressed time frame. (Colonel Setliff originally prepared this account of the restoration project for SolidWorks World 2007 in February in New Orleans.)
I want to emphasize two things. The first is to appreciate the scale and magnitude of the engineering effort that was required after Hurricane Katrina. It was an effort that rivaled the building of the Panama Canal. Second is to appreciate the strategic significance of the engineering work we were trying to do.
Before Katrina, there already were three strikes against the City of New Orleans. Strike one: it is a city surrounded by water. You have Lake Pontchartrain to the north, Lake Warren to the northeast, and the Gulf of Mexico to the east, west, and south. Strike two is the topography of the city. The predominant portions of the metropolitan area reside below sea level. Think about that: you’re surrounded by water and your city is predominantly below sea level. Strike three is the fact that the soils around New Orleans, unlike any other city in the country, are very different and that means the city sinks — it subsides at a rate of feet over decades, not inches over centuries. You have a city surrounded by water that is predominantly below sea level that sinks. Not a very good situation.
So what happened? Two very large storms, Katrina and Rita, were brewing in the Gulf of Mexico at Category 5. Some people said that when it hit the mainland, Katrina was only a Category 3. But these storms spent a significant amount of time in the Gulf of Mexico increasing in energy. What did the damage? Water. The storms pushed a tremendous amount of water onto the Gulf Coast, including Mississippi.
Hurricane Katrina was not the “perfect storm.” It actually hit to the east of New Orleans. But the momentum and inertia of the water that was generated by the energy of the storm pushed a tremendous storm surge against the Gulf Coast, specifically in New Orleans. Three weeks later, another Category 5 was in the Gulf and went to the west of New Orleans. Generally speaking, it didn’t do much damage because of the tremendous amount of damage Katrina had already done. Rita came through and basically poured salt in the wounds of an already catastrophically impacted city.
Maximum flooding depths ranged from 8 to 15 feet over entire neighborhoods. Eighty percent of the city was under water, and it wasn’t under water for hours, or even days. It was under water for weeks in the middle of summer in 100° temperatures. You can imagine what that would do to your infrastructure. It was absolutely catastrophic, and I’m not sure even that word explains what happened. The economic damages were substantial. It’s hard to imagine what those numbers were. The infrastructure damage alone was more than $75 billion dollars, with hundreds of billions of dollars in economic loss.
This was a very tragic storm of intense magnitude that overwhelmed the hurricane protection system that was designed to protect the city. The city was under mandatory evacuation orders, but there were several thousand people that elected not to evacuate. Unfortunately, when the hurricane protection system — a very complicated system of levees, floodwalls, floodgates, and pumps that surround the city — were overwhelmed, those people were at the mercy of Hurricane Katrina.
What you had, again, was a city surrounded by water that was predominantly under water and sinking over time, protected by earthen levees 15 to 18 feet high with floodwalls of similar height. There were 76 pumping stations that were required to pump rainwater out of the city. It had a very complex, defensive, protective system that had evolved over centuries. The first levees in New Orleans were built in the 1700s, so it was completely overwhelmed by the hurricane.
There are 350 miles of levees and floodwalls that protect New Orleans. Over two-thirds of those levees and floodwalls were damaged; several were catastrophically destroyed and failed to exist. Of the 76 pumping stations that the city relied on to pump water out, 66 of them were inoperable. And the energy source for all 76 was inoperable. The gated structures that control the tidal fluctuations out of the Gulf of Mexico became ineffective because the water had overflowed and eroded the land on either side. So the system that was there to serve and protect New Orleans was in disarray, it was inoperable, and it was dysfunctional.
That became my mission: to fix 220 miles of levees and floodwalls, to restore the pump stations to their effectiveness so the city could recover, and repair the gated structures. I summarize a very lengthy process that came down from The White House that said, in my words, “a very big storm, awful lot of damage, go fix it.”
Constructing a Plan
We had a plan, and this had been rehearsed. What we did not anticipate was the scope, the scale, and the magnitude of the damages that we would have to physically restore. What this required was for us to rewrite the books. The Corps of Engineers has been around for a long time — 227 years. We haven’t always operated the same way, but generally speaking, we did a very sequential engineering process that we learned in school: Assess, design, construct. But we realized that with the amount of damage we were talking about, we could do that, but we would probably be done in about 30 years, which is what it took to build the original protection system that was destroyed when Katrina hit.
It was a very unique challenge. We had to operate in an environment that was unexpected. There was no infrastructure and no power. There was water that you couldn’t drink, and on top of all that, we had to bring in what we thought would be an army of contractors to do the work and yet, there was no infrastructure — no roads and no housing to support them. We had to build our own camps and we had to ask our contractors to build their own camps and bring trailers with power and water to each one of these project sites just to facilitate their work.
We had companies that wanted to go to work, but their employees had evacuated, and we had companies who wanted to go to work and had employees, but their vehicles were under water. We had to marry these two just to get things done. We had to act as a government representative first, but we also had to act as a representative of the City of New Orleans, which needed
this work done before the next hurricane season started on June 1 — just nine months away.
We also had a very complicated social and political environment that we were dancing around in. I work for the President, who was actively engaged and monitored our progress on a weekly basis. He visited New Orleans frequently, and was very concerned about how Task Force Guardian, assigned by the Corps of Engineers, would do this engineering work. The people who worked for and with me are the reason I got up every morning.
We had people on our project sites just about every day — residents who had lost everything. They were there to make sure that when we were doing this construction — which was at breakneck speed — we weren’t sacrificing quality to meet our schedule. We were under intense media scrutiny, and we welcomed it, understanding that this city evacuated three-quarters of its population, if not more. We welcomed the media to assist us in telling our story and how our progress was coming along. People had to make some very difficult decisions, weighing their level of risk in order to come back to this city and recover. The predominant factor in their risk assessment was the status of the levees and floodwalls that protected the city.
More Than Engineering
So we had more than engineering challenges. We also had a significant time constraint. Looming in front of us was June 1, 2006, which was the beginning of the next hurricane season. We didn’t know in the fall, winter, and spring that there would not be a hurricane in 2006. Our assumption going in was that on June 2, there would be a hurricane.
We had thousands of contractors and hundreds of government employees who were all aligned with the same vision: repair this hurricane protection system and make those repairs before that hurricane we expected on June 2. I know as engineers we’re always being tested. I would be happy to never have the work we actually did be tested. But what this vision required us to do was throw out the playbook, redesign, rebuild, and reengineer the repairs we had to make, simultaneously. Sometimes it required us to take four steps forward and a step back, but it was absolutely necessary because we did not want to rebuild what was there before; we wanted to rebuild something better and stronger.
There were lots of initiatives being undertaken by universities and government agencies to determine why the hurricane protection system in New Orleans failed. It was absolutely imperative that if someone was doing a study on why a particular floodwall failed and reached a conclusion, we had better find out why during the process of our project execution. We spiraled in multiple times the findings of several groups that were doing analyses across New Orleans on why things failed.
There were three technologies we used in our work. First, there was an extensive amount of computer modeling that was done to determine primarily what forces were exerted on the existing hurricane protection system. Second, we used supercomputers to try and figure out what forces and how much storm surge hit New Orleans and the entire Gulf Coast. And we used scaled modeling of the 17th Street canal. This was all in an attempt to figure out where we had those breaches and why they occurred. When we found the answers, we got designers, engineers, and contractors who were doing the work in a room, at a table, and made sure that what they were building would account for what we identified had caused those breaches.
New Orleans is very unique — again, it is under sea level and there is a series of 76 pumps that collect the water when it rains and pumps it into three outfall canals, which then feed water out to Lake Pontchartrain. Unfortunately, with the hurricane, the exact opposite occurred. The hurricane pushed the storm surge into Lake Pontchartrain, up those canals. The canal walls failed, and the city flooded. If you add up the total amount of floodwalls and those three canals, it’s almost 14 - 1⁄2 miles of floodwalls. We made a decision in January of 2006 that the best way to reduce that risk was to close those canals with gates. In the face of a storm surge in the future, we could slam that shut, take the risk of those canals out of the equation, and provide a better level of protection for the City of New Orleans. We put seven gates inside one of those canals. Each one weighs 75 tons, and the gates themselves are 15 tons. We built them quickly by leveraging the existing offshore technology that resides in Louisiana with the offshore oil industry. So we had the expertise and we had the materials.
After the storm, the vessels across the region that had broken loose from the ferocity of the storm surge found their way onto our levees, and we had to take it upon ourselves to remove them, because the Coast Guard and the Navy did not see these officially as a threat to navigation. But they were sitting on our levees, so in order to get to the work, we had to move these seagoing barges and vessels — some of which, when fully loaded, weighed 300 tons.
I mentioned earlier about the soil stabilization, which is the center of all the problems in New Orleans. Soil stabilization was a key aspect we had to get right to build a better system. What we did was leverage recent technology that originated from engineers in Japan. One of our contractors brought a Japanese team here to help us stabilize the soil by drilling into the ground and injecting concrete, providing a stabilized base on which we could build our hurricane protection system. To build the three canal closures, we had to replace about 5 - 1⁄2 million cubic yards of clay.
Did we build a better, stronger system? You bet. We had to take some very innovative methodologies and apply them to our mission. At the end of the day, the engineering was done quickly, but it was done right. We provided increased stability, we used better soil, and we used several engineering features to make sure that this hurricane protection system is much better than it was before the storm. We also had to restore the confidence of the people who lived and worked behind those levees. We completed our engineering effort in 8- 1⁄2 months. We met our commitments to the people of New Orleans, and made the hurricane protection system better and stronger.