IE 11 is not supported. For an optimal experience visit our site on another browser.

Why New Orleans' $15 billion levee held and what experts worry about next

"We need to invest now for the future. That's the lesson we've learned from the investment in the levees," said Republican Sen. Bill Cassidy.

Norma Jean Mattei spent Sunday evening riding out Hurricane Ida in her home in Metairie, Louisiana. Once the storm passed, she set to work clearing debris from the street, checking on neighbors' homes and cleaning out her refrigerator.

While the storm brought terrifying, howling winds and tore shingles off roofs, Mattei, a lifelong resident of the area who evacuated for Hurricane Katrina, said a major reason she felt comfortable staying put was the $15 billion rebuild of New Orleans' levee system.

"We have a lovely and huge investment by the nation in our hurricane and storm damage risk reduction system, and, because I felt confident in the system that we have, I felt comfortable making decisions based on it," Mattei, a civil engineering professor at the University of New Orleans, said on a call Wednesday, an extension cord running from her neighbor's generator to charge her phone, her refrigerator and a fan.

Engineers, other experts and lawmakers said Wednesday that Hurricane Ida was a major test of the $15 billion federal levee, officially known as the Hurricane & Storm Damage Risk Reduction System. They said that the rebuild is the gold standard of levee systems in the U.S. and that its test was an important inflection point in the country's infrastructure debate — particularly as the U.S. faces increasingly damaging storms and weather patterns.

The London Avenue Canal in the Gentilly neighborhood of New Orleans on Aug. 31, 2021.
The London Avenue Canal in the Gentilly neighborhood of New Orleans on Tuesday.Patrick T. Fallon / AFP via Getty Images

"This was a very significant test, especially in the West Bank," the suburbs west and south of the Mississippi River, said Ed Link, a research engineer at the University of Maryland who was the principal investigator of New Orleans' storm system after Katrina. "A lot of these new structures have not really been put into a real game, beyond some practice time with smaller hurricanes. So we have a test now, though it's nowhere near close to Katrina."

When Katrina struck the Gulf Coast 16 years ago, the storm surge overtopped and broke through the levee system, which previous generations of leaders had taken cost-lowering shortcuts to build. The result was devastating flooding in New Orleans, which contributed to more than 1,500 deaths.

After the storm passed and once the city began to rebuild, Link and the Army Corps of Engineers worked to find the faults in the system. None of the structures before Katrina had been designed to withstand water overtopping the levee.

"Bottom line, it looked a whole lot more like sausage-making, saving money and someone's biases for this or that than it did precision engineering and design," Link said, referring to the old levee system.

The rebuild began in 2006. Richard Campanella, a geographer with the Tulane University School of Architecture who has written extensively about New Orleans and examined the new levee and pump system closely, said a substantial part of his decision to stay in the city through the storm was his knowledge of the risk reduction system and the city's new pumping station, which he said was "awesome."

"The system was built within a period of about five years, 2006 to 2011, which would ordinarily have taken 30 to 50 years," he said.

Campanella said the levees were built to withstand a 100-year storm, which would be weaker than Katrina but is the standard set by Congress and the National Flood Insurance Program, the federally backed program that allows property owners to buy insurance in flood-prone areas and requires them to adopt land use and flood control measures.

Some, like Link, say New Orleans requires a higher threshold, as the standard could be affected by climate change and sea level rise. "That's our standard for flood insurance," he said. "It's not a standard for protecting hundreds of thousands of people."

But multiple experts said the levee system is limited by the country's priorities and values.

"If one wants to envision a world of unlimited resources, you could have aimed higher," Campanella said. "If you have a world of limited resources, however, you have to make tough decisions."

But experts also noted that Hurricane Ida did not test one of the city's major weaknesses: its drains.

We apologize, this video has expired.

Ida, which did push some storm surge against the levee walls, did not provide the same damaging amount of water as Katrina or stall out over New Orleans and dump huge amounts of rain on the city. Many experts said that was a godsend, because the city's drainage system remains its main Achilles' heel.

"There is just a major need for that system to be upgraded and its capacity increased, because the amount of rainfall it was designed to be able to manage is small potatoes compared to what a hurricane or tropical storm would provide," said Rick Luettich, the director of the University of North Carolina's Institute of Marine Science, who served on the board of the New Orleans flood-protection authority.

That is no small task, as it would require redoing the city's entire plumbing system, but drainage is essential.

Because New Orleans is below sea level, its drainage and pump system is electric rather than gravitational. That means it relies on the power grid or generators to move water up and out of the city.

The two generators in New Orleans that operate the system are so outdated that the agency that runs them has to build its own parts in-house to repair them, Campanella said. There has been a growing effort to connect the pumps and drainage system to the main power grid, but the fact that that has not happened yet also proved to be the city's saving grace. When electricity went out across southeast Louisiana, causing some areas to lose sewer and water service, the generators kept New Orlean's water systems flowing.

"It's a lesson in the value of redundant systems, and it's also a commentary on the incredible engineering of the early 20th century," Campanella said.

While New Orleans largely dodged a devastating blow, the communities surrounding it continue to struggle with rampant flooding. A key issue is the loss of natural protections, such as the depleted wetlands along Louisiana's coast and the disappearance of its barrier islands.

Experts said focus needs to be renewed on creating a mix of "green" and "gray" infrastructure to further protect coastal communities across the country.

"Outside the fortress of New Orleans, those folks are a lot more vulnerable to storms," Link said. "They're looking at alternatives like marshes and some mix of green and gray infrastructure, but I don't know where the money is going to come from to do that."

Sen. Bill Cassidy, R-La., who helped write and pass the bipartisan infrastructure measure, has some ideas. He said that New Orleans and the surrounding area were saved from major damage because of the rebuilt levee system — but that there is more work to be done.

He said the infrastructure bill, which the House is scheduled to vote on at the end of the month, would help harden the country — as well as Louisiana — against natural disasters by investing billions of dollars in the country's levees, flood mitigation and coastal restoration programs, water systems and electric grid, as well as expansion of access to broadband, which would help keep people informed.

"The flood mitigation system, more than just the levees, truly mitigated the risk, and, 16 years after Katrina, we are benefiting," Cassidy said over the phone as he toured the damage caused by Ida. "We need to invest now for the future. That's the lesson we've learned from the investment in the levees."

Cassidy hopes his Republican colleagues in the House will back the $1.5 trillion infrastructure bill when it comes up for a vote this month, and he emphasized that the bill is separate from the second infrastructure bill pushed by Democrats.

"I think they need to put the politics behind them and think about what's going on in people's lives," he said, referring to House Republicans.