New Orleans is now protected against a 100-year storm, but that doesn't mean the city is invulnerable to another Katrina.

The $14.5 billion system was in place by 2011, although it wasn't quite finished. Those pumping stations were only temporary; the permanent ones are not expected to be finished until 2017.

Even so, the pumping stations were built close to Lake Pontchartrain, where they can block another storm surge from using the drainage canals as a highway into the city, as happened during Katrina.

Yet the city's 100-year protection isn't as impressive once you know that Congress originally called for a system that would guard the city against a much stronger storm.

In 1965, Congress ordered the U.S. Army Corps of Engineers to provide the city with a system that could withstand a 200- to 300-year storm. Those "year" designations are based on the storm history of a particular area. A 100-year storm has a 1 percent chance of occurring in any year.

The corps considered Katrina a 400-year storm, or a low Category 5 event, when it reached  New Orleans.

After Katrina, New Orleans and Louisiana politicians wanted a Category 5 system. Two factors led them to settle for less: The Bush administration did not want to pay for the stronger system, and it was important to build something quickly.

City and state leaders worried that no one would re-invest in the city until it qualified for federal flood insurance, which requires 100-year protection, said Mark Davis, director of the Tulane Institute on Water Resources Law & Policy. Anxious that it could take years to get something stronger, the city and state accepted what they could get from Washington.

The new 100-year system, however, is almost certainly stronger than the one in place before the storm. Though the old levee system was supposedly built for a 200- to 300-year storm, Katrina revealed serious engineering and construction weaknesses that caused catastrophic failures.

Plans are underway to "armor" the new levees with a protective layer. Once that's done, they're expected to be strong enough to withstand a 500-year storm without collapsing — although anything stronger than a 100-year storm probably would push water over the top.

Fortunately, in most storms, that wouldn't be catastrophic because storm surge usually lasts for only a few hours. Minor flooding could be pumped out by the city's drainage system.

In the immediate aftermath of Katrina, the Bush administration said it would look at Category 5 protection in the future.

Obama elevated that to an "ultimate goal." But there's been little progress.

Before we go further, you should know that there's no way to convert a 100- or 500-year storm to the category 1-5 system you're used to hearing about. It's not like Celsius and Fahrenheit.

Moreover, experts and engineers no longer refer to the category of a hurricane when discussing storm surge. The category system is based largely on wind speed, and experience has shown that a Category 1 storm can push as much water onshore as a Category 3 storm.

Even so, experts agree that the storm surge from a Category 5 hurricane would be greater than a 100-year storm.

At the direction of Congress, in 2006 the corps produced a report saying a Category 5 system around New Orleans would require 30-foot levees and cost about $11 billion. Levees and floodwalls around New Orleans range from 10.5 to 30 feet high.

No further action has been taken to build a Category 5 system around New Orleans.

John Barry, former vice president of the regional levee system responsible for New Orleans, was actively involved with the state's congressional delegation in lobbying for the new levee system. He couldn't recall any further discussion of building a Category 5 system.

The new levees and floodwalls around New Orleans would provide some protection in a Category 5 storm. With armoring, the corps says levees wouldn't collapse in a 500-year storm, which would prevent a Katrina-level disaster.

But water would almost certainly pour over the top of the levees in many parts of the city in a Category 5 hurricane. Depending on how much water came into the city and how hard it rained, the city's pumping system may be able to floodwaters from reaching houses. 

We rate this Compromise.

Editor's note: On the 10th anniversary of Hurricane Katrina, PolitiFact has partnered with The Lens to report on President Barack Obama's campaign promises about the storm's impact on New Orleans. The Lens is a nonprofit, public-interest newsroom that covers the New Orleans area.

In the wake of Hurricane Katrina, the federal government (along with state and local help) committed more than $14 billion to develop a levee and pumping system around New Orleans capable of protecting against a 100-year storm. It would be the biggest civil works project in the history of the Army Corps of Engineers. And Obama promised it would be completed by 2011.

As promised, nearly six years since the devastation of Hurricane Katrina, that goal has largely been accomplished.

According to a May 29, 2011, story by Mark Schleifstein of the New Orleans Times-Picayune, "The new system represents an unprecedented engineering feat that took six years to build, with more than $8 billion spent so far on design and construction. And it required a complete rewriting of the rules used by the corps to build both levees and hurricane levees."

In order to meet its goal by June 1, the start of the hurricane season, the Army Corps of Engineers relied on some temporary fixes that may take several years to complete. One levee section was delayed by Mississippi River flooding. And some temporary gates and pumps will be replaced with permanent equipment. But the goal has been functionally completed.

A May 29, 2011, editorial in the Times-Picayune applauded the milestone: "The corps has met its ambitious time frame for the most part, and that itself is a significant accomplishment that deserves to be saluted."

But even as it saluted the achievement, the paper's editorial board warned there is still "the pressing question of providing defenses from stronger storms -- like Hurricane Katrina."

That gets to the second part of Obama's campaign promise, to point toward "the ultimate goal of protecting the entire city from a Category 5 storm."

To that end, a federal task force sent the Louisiana Coastal Protection and Restoration Study to Congress last year including several options to reach that longer term goal -- along with a projected price tag in the neighborhood of $100 billion.

John Barry, vice president of the Southeast Louisiana Flood Protection Authority-East, said the levees designed to protect against a 100-year storm are "pretty much finished" and that he's satisfied the corps has met that part of its goal.

The task force study of protection options for a Category 5 storm was a "significant initiative," Barry said, but much more needs to be done.

"They came up with a roadmap," Barry said. "But we are still talking about process and concepts rather than actually doing anything. I'd score that as a reasonable step."
In its editorial, the Times-Picayune warned that stronger protection was crucial.

"Completing 100-year protection is a noteworthy accomplishment and deserves to be celebrated," the paper wrote. "But it must be the beginning and not the end."

Although there are some loose ends still to tie up, we think Obama and the Army Corps of Engineers can claim to have met the goal of providing a levee and pumping system to protect the city against a 100-year storm. Obama also said the "ultimate goal" was to protect the city from a Category 5 storm. That was aspirational, not a promise to complete such protection within his term. The federal government has begun serious study of that, and while much more needs to be done to make that happen, we feel Obama has lived up to the measure of this promise. We rate it a Promise Kept.

This is actually a two-part promise.

The first part deals with ensuring that New Orleans has a levee and pumping system to protect against a 100-year storm by 2011.

And that part is moving along. The Army Corps of Engineers is more than one-third of the way through construction of an improved levee system to provide 100-year flood protection for New Orleans, and White House officials say the administration is committed to keeping these projects on track to be completed by 2011.

To date, over 220 miles of levees and floodwalls have been repaired and restored to pre-Katrina levels of protection. According to White House officials, the levees and flood walls that were breached during Katrina have been rebuilt to stricter standards and are fortified so that they will withstand a 100-year storm surge.

In addition, storm-surge protection has been installed at Lake Pontchartrain and multiple pump stations have been installed or updated around the perimeter of the city. In addition, some levee armoring has been installed to make the levees more resilient.

Additionally, Congress appropriated $439 million to restore islands along the Mississippi Gulf Coast that serve as the first line of defense against hurricanes.

So we think it's fair to say that Obama has made progress on this front.

But the jury is out on the second part of this promise, "the ultimate goal of protecting the city from a Category 5 storm."

Allison Plyer, deputy director, Greater New Orleans Community Data Center, notes that Katrina was more like a 400-year storm. Even with 100-year storm protection, she said, New Orleans would suffer significant flooding if hit with another storm the size of Katrina.

And, she said, "we have seen no progress toward that (protecting the city from a Category 5 storm); we have not seen any federal attention to that issue."

In an interview with the New Orleans Times-Picayune , published on Aug. 23, 2009, Obama said Category 5 storm protection "is still an aspiration." He said there is an "interagency working group" on the issue.

Since Obama's promise to protect New Orleans from a Category 5 storm was described as an "ultimate goal," we think it's fair to say that was a longer-term goal. Still, we'll keep an eye on this and assess if lack of progress on the longer-term pledge means the promise has become Stalled. But for now, we think there has been enough progress toward rebuilding and repairing the levee and pumping system to protect against a 100-year storm to rate this one In the Works.