New Orleans Levee System Provides Unparalleled “Risk Reduction,” But No Guarantees, U.S. Army Corps of Engineers Says

IMG_0585The chief of public affairs  Ricky Boyett explains the details of the post-Katrina levee system.

By: Vincenzo Ciccone

NEW ORLEANS – As worries deepen about the safety of the New Orleans levee system some 12 years after the Hurricane Katrina debacle, officials charged with re-evaluating, re-building and inspecting the city’s storm surge defense system say the levees, the last line of defense between the city and a storm surge, form a nearly impervious “walled city.”

Ricky Boyett, public affairs chief for the New Orleans District of the U.S. Army Corps of Engineers, says there is little comparison between the pre-Katrina system and today’s state of the art system.

“The system is fully changed,” said Boyett. “The existing system was a system in name only. There were 350 miles of levees and floodwalls that lined the canals, but what that did is it allowed the water to get into the interior of the city. We changed our approach and took a perimeter approach where you have instead of 350 miles of floodwalls and levees you have 170 miles of levees and floodwalls and what we call complex structures such as surge barriers that prevent storm surges from ever getting into the interior of the city in the first instance rather than containing or managing it after it has already arrived.”

Boyett, however, stopped short of calling the levees safe, preferring instead to conclude merely that the “system will do what it’s designed to do” in terms of “risk reduction.”

The public outcry and Congressional hearings following the Katrina debacle examined all aspects of what went wrong during Katrina from both political and technological standpoints, and the result was the allocation of $14.5 billion to develop a system to defend against a 1 percent storm, which is a storm surge event that has a 1 percent chance of occurring in any given year, according to Boyett.

The pre-Katrina system focused resources on lining canals, a failed approach that left the city vulnerable. This approach was replaced by the current advanced system that is based on what Boyett calls “advanced technology and science.” The modern approach, developed by Boyett and his colleagues, defends the entire perimeter of the city with surge barriers replacing the pre-Katrina system that lined only the canals.

“Pre-Katrina, water was able to get into the Industrial Canal because the levees only lined the canals,” said Boyett. “But now we built a surge barrier consisting of a nearly two mile long wall that blocks the surge from the east and doesn’t allow it to get into the Inter coastal in the first place. Then, we built the Seabrook Floodgate on Lake Pontchartrain which prevents the surge from going from Lake Pontchartrain to the Industrial Canal from the other approach. It also keeps the water out of the flood walls along the Ninth Ward, which are now only secondary lines of defense used for internal drainage management rather than the first line of defense against storm surges as it was in the pre-Katrina system.”

Boyett’s perspective on the science of defending the city against storm surges is influenced by 100-year projections on sea level rise, subsidence and other factors.

For example, the city reportedly covers 350 square miles of land mass, including 180 square-miles of water within its borders. The average elevation is between one and two feet below sea level with some areas as much as seven feet below sea level, and the levees are typically built at an elevation of 22 feet. Global warming and climate change generally make considerable shares of the assets, people, economies and water supplies existing in coastal regions like Louisiana among the most vulnerable in the entire world, a set of circumstances that may eventually spell disaster for the city, according to a Congressional Research Service report. 

These alarming facts, together with the bleak pre-Katrina reality, were taken into account by the Corps during the planning stages. “We did not gamble with public safety,” assures Boyett. “All calculations are conservative, so when we say 100-year levels it’s greater than projected which allows us to take into consideration sea-level rise, subsidence and other factors in the future.”

These alarming facts perhaps also form the reason Boyett is cautious in his assessment of whether the system is absolutely safe.

Congress, however, appeared to look specifically at the issue of absolute safety when it allocated federal funds and directed the Corps to begin work on the project of re-building the levees nearly 12 years ago.

The U.S. Senate’s Committee on Homeland Security and Government Affairs did not equivocate in its sweeping condemnation of the pre-Katrina system as “fatally flawed in design, construction, or maintenance” resulting in the levees “not merely being overtopped, but actually crumbling before the onslaught of the storm.”

The Committee hearing transcript makes clear that certain senators were dismayed over the lack of transparency on the issue of safety and even noted that key officials at the Corps and the Orleans Levee District had changed their position in sworn testimony before Congress. Boyett was not among those key officials whose credibility was questioned, and the current edition of the Corps seeks to recover from those troubled days.

The Corps accepted the daunting task suggested by its Congressional mandate to re-evaluate all aspects of the failed pre-Katrina system, including how levees are built.

“We re-evaluated how the Corps builds levees, how the battering piles go in,” said Boyett.  “Pre-Katrina we used most ‘I’ walls. Now, we use ‘T’ walls, which are literally built like an upside down ‘T’ with superior piling underground. There is no comparison before and after in terms of these flood walls now being built with the latest data.”

Ensuring the safety of the system is further complicated by the openings in the system along the perimeter of the city.

“There are 455 openings along the 173 mile perimeter of the system where water flows in and out of the city naturally,” said Boyett. “The Corps recognizes the flow of water is an integral part of the city’s cultural and economic vitality, and it built the system to preserve this vitality without compromising safety.”

Alicia Plummer, a local politician, agrees with Boyett’s view. “I pretty much believe the levees are safe. The Corps of Engineers spent extraordinary amounts of money to shore up and certify the levees,” said Plummer.

The issues of inspection and maintenance raised by Plummer have been addressed by the Corps.

“The inspection and operation maintenance process is far greater and more robust than it was pre-Katrina,” said Boyett. “Hurricane systems must have regular maintenance to remain effective. After the Corps builds the system, it turns over inspection and maintenance to local and non-federal agencies to operate and maintain it. The Coastal Protection and Restoration Authority is a state agency that actively inspects the levees. The Sewage and Water Board of New Orleans

and the Louisiana Department of Transportation are also involved in the process. This system, which is unparalleled in the country in terms of risk reduction, cannot operate in a vacuum.”

The efficacy of the system was tested by Hurricane Isaac in 2012 and passed with flying colors, according to Boyett.

“Every component of the system was tested during Hurricane Isaac,” said Boyett, “and the system performed as designed. Today the system is only stronger than it was in 2012, and we are fully confident it will defend the city against storm surges in the future.”

Some 12 years after the Katrina debacle, area residents are considerably less confident than Boyett.

Terrell Baylor, 22, who resides in the Ninth Ward, disagrees with the experts. “Whenever I hear rhetoric like they use when they talk about a walled city,” said Baylor, “I think of famous last words. Hurricane Isaac was not a real test of the system. You can go downtown and eyeball the water levels and know that the weight of that sea is mighty and way above the land.  The existing system is nice, but can it take a real punch, like the one delivered by Katrina? I seriously doubt it. Everybody I know is worried about the levees being unsafe. It’s a fact of life in New Orleans.”

Anthony Montgomery, 24, echoes those sentiments. “I really don’t see where the new system is safe or where all of that federal money went. The levees are better, but they are not as strong as they could be. Everything the government does is always sent out to the lowest bidder. In turn that bidder cuts corners to save money for themselves.”

Restoring public confidence in the post-Katrina era appears to be among the challenges of the Corps’ work even as the levees continue to defend the perimeter of the city against the eventualities of sea level rise, subsidence, global warming and future storm surges.

“Unfortunately, we probably will not know if the levees are absolutely safe until they are tested by another event like Katrina or something close to it,” said Plummer.

(Levee wall by UNO)IMG_0552.JPG

(Canal Interim Closure Structure)IMG_0579

(Canal Interim Closure Structure)IMG_0580


Hurricane Katrina Documentaries:

Documentaries on Rebuilding the Hurricane Levee System:

Congressional Research on Sea-Level Rise:

Transcript of the Hearings on Hurricane Katrina before the U.S. Senate Committee on Homeland Security and Governmental Affairs:

U.S. Army Corps of Engineers:


Rivlin, G. (2015). Katrina after the Flood. New York: Simon & Schuster.


Crowell, M. (2010). An Estimate of the U.S. Population Living 100-Year Coastal Flood Hazards Areas. Journal of Coastal Research, 26, no. 2, 201-211.

Global Warming Effects and Causes:


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