Environment
 

Best-ever levee system is here to protect property, not lives, experts warn

A new, stronger levee and flood wall protects the Lower 9th Ward from the Industrial Canal. This was the section that failed after Hurricane Katrina, letting a barge float through and flooding the working-class neighborhood and washing away home.

Edmund D. Fountain

A new, stronger levee and flood wall protects the Lower 9th Ward from the Industrial Canal. This was the section that failed after Hurricane Katrina, letting a barge float through and flooding the working-class neighborhood and washing away home.

Rick Luettich is a world-renowned hurricane storm-surge modeler who sits on the board of the New Orleans flood-protection authority. He said the city’s new $14.5-billion levee system designed to repel a 100-year storm is bigger and stronger than the one that collapsed with deadly consequences during Hurricane Katrina.

But he’s also a parent and put the protection in personal, practical terms.

This story was produced in conjunction with The Weather Channel. More Hurricane Katrina anniversary coverage can be found here.

This story was produced in conjunction with The Weather Channel. More Hurricane Katrina anniversary coverage can be found here.

“If my daughter was buying a house in New Orleans with a 30-year mortgage, I’d have to tell her there’s a 25-percent chance water will come over the top of that system before she pays off the mortgage.

“Now, the consequences probably won’t be catastrophic like they were during Katrina. But that 1-in-4 chance is there,” he said.

Of all the questions being asked about New Orleans’ progress 10 years after the disaster that killed nearly 1,500 residents and clouded its future, the most persistent has been this: Is it safer now?

Interviews with engineers and storm experts resulted in answers filled with caveats and concerns such as Luettich’s.

The best summation: It’s safer for houses, but not necessarily for the people who live in them.

That’s because the new system is the city’s best engineered and built ever, but it was designed to a lower level of protection than the one that failed. It’s also less than what Congress ordered in 1965. It was built to provide property insurance, not save lives. And experts insist it’s insufficient for an important city sitting on a sinking delta in hurricane alley during the age of climate-induced sea level rise and mega storms.

 The need for more protection from more intense storms varies across the city.

Evan Travelstead / The Weather Channel

The need for more protection from more intense storms varies across the city.

 

THE ORIGINAL VISION

The story begins in 1965 when Congress, shocked by Hurricane Betsy’s damage, authorized the Lake Pontchartrain and Vicinity Hurricane Protection Project. That law ordered the Army Corps of Engineers to build a system strong enough to repel a storm consisting of “the most severe combination of meteorological conditions that are considered reasonably characteristic of the region.”

It would be a great improvement on the various levees pieced together over the decades by separate authorities in adjoining parishes.

That description was based on a model called the Standard Project Hurricane, which the corps used to determine the height of the walls and levees around New Orleans. The corps said such a storm would be so severe it was likely to occur only once every 200 years along the Louisiana coast.

When the Saffir-Simpson Scale of rating hurricanes came into use in the 1970s, the corps rated the Standard Project Hurricane a Category 3. Later revisions to the model would raise it to a Category 4, reports said.

But as Hurricane Katrina barreled toward the city 40 years later, it faced only a partially completed Category 3 system. A project the corps expected to build in just 13 years at a cost of $85 million now had a price tag of just under $1 billion – and a new completion date of 2017.  Yet as early as 2002 hurricane researchers at Louisiana State University had already predicted the system had been designed too low for a storm of Katrina’s size.

That system, criticized as “a system in name only” by the corps itself, suffered about 50 breaches during Katrina. Although the corps would consider Katrina a low Category 5 storm, its own investigations showed most of the breaches were not the result of the storm’s fury, but of errors in engineering and construction.

In the aftermath, city and state officials initially demanded a Category 5 system, which a corps report said would call for 30-foot high levees – more than 10 feet higher than many spots in the old system. The estimated cost just for the east bank of the metro area was almost $11 billion.

The sequence of levee breaches that flooded the city in 2005.

Evan Travelstead / The Weather Channel

The sequence of levee breaches that flooded the city in 2005.

CUTTING A DEAL SO REBUILDING COULD START

But those same officials quickly backed away from that gold standard and settled for something far more necessary for the immediate recovery of a crippled city: A system that would pass muster with the federal flood-insurance program. Getting such a system underway would allow rebuilding to start. They reasoned that they could bargain later with the federal government to get better protection.

They never had a chance.

The Bush Administration’s budget concerns and the Republicans’ takeover of the U.S. House and then the Senate meant little more attention or money would be given to a system deemed adequate.

“There could be no rebuilding or attracting and keeping businesses without flood insurance,” said Mark Davis, director of Tulane Institute on Water Resources Law and Policy who was head of the Coalition to Restore Coastal Louisiana in 2005. “There was an urgency, almost a panic, over the issue.”

A system that qualified for national flood insurance would be lower, less expensive – and much quicker to build than a Category 5 system, engineers said.

So when the Bush administration said it would only commit to Category 3 protection immediately and study Category 5, the city relented. Yet within months after the storm, even that standard had been lowered.

At the time, a Category 3 storm was considered one that returns every 200 to 300 years. But since FEMA would certify the city for flood insurance with only a 100-year system, that’s what Congress ordered and appropriated.

It was a landmark shift in the nation’s commitment to protecting New Orleans. Suddenly all mention disappeared of the Standard Project Hurricane and “the most severe meteorological event likely to occur” – the standards for protection that had been part of every revision to the original authorization for 40 years.

The immediate impact, engineers said, was reducing the design of levees and floodwalls about 2 to 4 feet on average across the system.

“It’s as if your poorly built, three-story house collapsed, so the contractor said, ‘Ok, I’ll replace it with a well-made, two-story house,’ ” Davis said.

Johnny Holzenthal of the Orleans Levee District check for cracks and other anomalies in the Orleans Avenue Canal levee earleir this month.

Edmund D. Fountain

Johnny Holzenthal of the Orleans Levee District check for cracks and other anomalies in the Orleans Avenue Canal levee earleir this month.

PEOPLE VS. PROPERTY

But the switch to the flood-insurance standard had another, equally troubling effect, engineers said: A system designed to reduce property losses does not have to be as robust as one designed to protect lives.

That change can be seen in the titles of the two systems. For 40 years, the law required a “hurricane protection system.” The new project is called a “storm damage risk reduction system.”

“In effect, it’s not really a standard that’s been set for safety reasons. It’s a standard that’s been set for obtaining affordable flood insurance only,” said Bob Turner, an engineer who is the regional director of the Southeast Louisiana Flood Protection Authority-East.

“The system should be based on protecting what’s at risk,” he stressed, “and in a highly populated urban area, that is something much greater than the cost of property damage.”

New Orleanians should understand they live inside a system that promises only to help pay for property damage, not protect their lives, said Bob Jacobson, an engineer who reviewed the system for the flood protection authority.

“It’s like any other insurance policy,” he said. “Your fire policy doesn’t say it will protect your life during a fire. If your house catches on fire, you have to leave, and when you come back you’ll have enough money to rebuild.

“That’s what this system says. If you want to be safe, you have to evacuate. And when you come back, you might have enough insurance to rebuild.”

But even the critics say the new, lower-level system makes the city safer because it is better built and sturdier than the old one, thanks to changes in design and closer oversight by local authorities. They are confident the new levees and floodwalls will not collapse, or breach, like the old ones even in major storms.

And breaching, not being overtopped by a storm surge, is the real danger. For example, post-Katrina studies indicated that if the levees in St. Bernard Parish had only been overtopped, flooding in that area might only have been have been shin deep instead of reaching rooftops.

“Overtopping is something the city’s drainage system can probably handle,” Jacobson said. “But when you have failures, the lake pours in.”

The corps also added new features that make the city safer from such a Katrina-style inundation. The outfall drainage canals that were open to storm surge into Lake Pontchartrain have now been closed off, as has the Mississippi River–Gulf Outlet shipping channel. And the corps built a massive, $1.1 billion storm surge barrier across the western end of Lake Borgne.

They also say once the grass on the city-side of the levees is reinforced with a synthetic mesh base – a process called armoring – the levees should not collapse even when the surge from a 500-year storm pours over their crests.

Because of that the corps claims the armoring will give the system “500-year resiliency,” but Luettich warns that still isn’t enough.

“A 100-year system with resilience added does not provide the same level of confidence as a system built to a 500-year standard,” he said.

“It’s sort of back-engineering,” he said. “Up front, it should have a much higher design standard applied to it. And in the long run that’s what you want for this area. I’ve always said that, and I still believe that.”

Part of the region's new levee system features this  barrier, which is designed to block incoming surge from the Mississippi River — Gulf Outlet canal and the Gulf Intracoastal waterway.

Edmund D. Fountain

Part of the region\’s new levee system features this barrier, which is designed to block incoming surge from the Mississippi River — Gulf Outlet canal and the Gulf Intracoastal waterway.

STAYING AHEAD OF SINKING

However, funding is not the only obstacle to better protection. The region’s serious environmental issues pose challenges to levee design and safety.

All of southeast Louisiana rests on deltas of the Mississippi River that are sinking due to flood-protection levees that blocked river sediments, as well as thousands of miles of canals dredged for oil and gas. The subsidence is so rapid the corps already had to raise some sections of the newly built levees more than a foot before they were turned over to the state. And the local authority knows it will face tens of millions of dollars in future levee lifts to maintain the heights needed to stay qualified for federal flood insurance.

That sinking and erosion has also been removing the wetlands that once protected levees from punishment by the Gulf of Mexico’s waves. Some 2,000 square miles of coastal wetlands have been turned to open water since the 1930s, and more is being loss at the cumulative rate of a football field every hour. The National Oceanic and Atmospheric Administration reported that at those rates the remaining wetlands protecting the levees could be under water before the end of the century.

Hurricane surge protection levees are built of soil because they have to repulse surge only for a few hours or days. If they are sitting in water 24/7, engineers say they will collapse. The state has a $50 billion, 50-year plan it hopes can reverse that trend in areas around New Orleans.

The soft soils means building protection from stronger than 100-year storms may not mean higher levees but flanking the current system with wave protection.

“Money aside, there’s a limit to how high you can build levees on those soils,” said Paul Kemp, a coastal geologist and member of the flood protection authority board.

“We can build wave barriers in front of the levees and plant coastal forests, and rebuild the wetlands. We know climate change means we’re going to need a higher level of protection in the future with sea level rise, so these are things we need to be thinking about now if we want to provide even 100-year protection in the decades ahead.”

For New Orleans to feel safe, the engineers and storm experts said, the nation should have built a true 500-year system, with armoring to prevent breaches during even larger storms. But even that would not remove the only true way to protect lives when a storm approaches.

“The truth is, what we have in place is a system built on the best guesstimates we can currently can make,” Jacobson said.

“Protecting lives in a big storm now means getting people out of the way – so we can rebuild when we come back.

“That’s the reality we have to admit and invest in.”

Tulane’s Davis agreed and said only 100-year protection is a mistake.

“A major metro area that has only a razor-thin commitment with insurability is one that is gambling with its future,” he said. “In 1965, Congress said we needed and deserved a level of protection to meet those risks. We still do today.”

Help us report this story     Report an error    
The Lens' donors and partners may be mentioned or have a stake in the stories we cover.
  • Chris McLindon

    Nice work Bob. Unfortunately you can’t interview Dr. Roy Dokka of the LSU geology dept., as he passed away in 2011. He did leave us with a legacy of good work from which we can continue to draw. In a 2006 study with Dr. Tim Dixon of Univ. of S. Florida they said:

    “Parts of St Bernard and Orleans Parishes west of Lake Borgne are experiencing subsidence rates of more than 20 mm/yr, including the levee system along the MRGO canal. Parts of this levee system were breached during the flooding associated with Hurricane Katrina, and this could be explained by the correlation we observe between the location of breach points and the high rate of subsidence beneath these levee sections. Our subsidence estimates are probably minimum values considered over the lifetime of the levees, given that subsidence was most rapid in the first few years after their construction in the 1960s. Levee failure may have resulted from overtopping because the levees were too low — data collected after the storm indicate that water levels exceeded those expected by 0.9–1.7 meters. Alternatively, the high subsidence rates we observe might reflect active faulting or a weak, easily compacted substrate, promoting failure at or near the levee base.”
    The image shows some highlights of our current knowledge of the geology of the area where the levee failure occurred, but there is much more to be done. The is an obvious relationship between the evidences of the geologic faults and the patterns of subsidence in the area. Fort Proctor stands as a testament that the same forces of subsidence that are impacting the levees today have been active for at least 150 years.
    Unfortunately the world-class coastal research facilities at our universities are being starved of funding. If we can get an accurate mapping of the faults that are causing the subsidence (an probably the levee failures), we may be able to focus attention in those areas to monitor the integrity of the infrastructure system, but we have to start with a re-invigorated research effort to understand the geology that is controlling the changes in the wetlands and the sustainability of the protection infrastructure.

  • KC King

    There is a major flaw in this article regarding evacuation. There really is a continuum of shock and stress ranging from a 3 day mildly inconvenient outing with immediate return to a clean house on one the hand and on the extreme, there’s returning after 7 months to the shock of a destroyed house facing years of incompetent and unintentionally malicious bureaucracy, hundreds of thousands of dollars out of pocket and acute depression. There is also the option of not returning at all and permanently relocating for better economics or schooling which many residents with foresight selected

    The explicit intent of the IPET’s findings of a “system in name only” is that creating tolerable resilience can only occur when structural protection and non-structural elevation or relocation emerge from a well-crafted system and are integrated to dramatically reduce an unconscionable shock to a tolerable stress.

    It is very clear that every house below the Katrina high water mark is vulnerable to the highly unlikely put distinctly possible and near inevitable devastation experienced during Katrina. It is equally clear that the Road Home elevation grants did not promote resilience in our housing. Added to this are organizations that are saying that flood insurance is too expensive because there really is no risk and discouraging safe elevation. On its part the city is promoting shocking evacuation by leaving its BFE at a level that has been found by the National Academy of Science to be bad science and irrelevant to extreme floods.

    During the Katrina 10 events, the Mayor, and only the Mayor, has articulated a truly resilient vision about the critical need for integrating our given structural protection with our nonstructural home elevation to be a true, resilient system. The IPET’s finding demands that we take those two “subsystems” and integrate them with other well-formed subsystems in a total system where the whole is significantly greater than the sum of its parts and allows us to meet all our extreme threats

    It is time to recognize that the discipline of urban planning has, in this city, failed again and again to grasp the extreme uncertainty, complexity and disastrous consequences of extreme weather events. What is needed is for the city to follow the best practices of other institutions who confront extreme uncertainty, complexity and consequences such
    as the space program and aviation, in adopting proven best systems engineering practices. Anything less or ad hoc such as the New Orleans Resilience Strategy will insure we are, once again, woefully unprepared.

  • dimdingledon

    These findings were known by the SLFPA-E for years, but the Doody-Barry led SLFPA-E decided to do nothing. Dr. Dokka gave this presentation to the SLFPA-E in 2008 and warned them of the catastrophic results if no actions were taken. At that time he estimated there was a 10-year window of opportunity before reaching a point of no return. We are just about to that point and no restoration work has been done yet. And the real kicker is this assumes all of the storm surge modeling was done without error in judgement. It wasn’t it actually low balled the surge heights by including less intense storms and tracks spaced too far apart that does not account for our actual flood threat. I’ve said this for years and I’ll say it again, the levee reconstruction was one of the biggest scams pulled on the citizens of New Orleans. Control of the SLFPA-E was done by the NOBC and the sole intent behind the scheme was to get people back to the city as fast as possible so the NOBC members would not lose their businesses. The citizens of New Orleans has been sold another bill of goods.

    Here is an example of how the SLFPA-E and its consultants twist the truth to fit their intent, “Overtopping is something the city’s drainage system can probably handle,” Jacobson said. Not true!! First of all, the S&WB system ids designed for a 10-year rainfall event. The Corps incorrectly selected the 10-year rainfall event rather than the 100 year rainfall event when designing the new system. So right from the beginning the flooding was under estimated. Secondly, since the S&WB can only handle a 10-year rainfall event, how can it handle the additional floodwaters caused by overtopping. It can’t!!