The investigations

In the months and years after the flood, engineers and scientists descended on New Orleans to figure out what went wrong. Seven major investigations resulted. You can read summaries of each in The record. This lesson tells the story of how they unfolded — and why the order in which they came out mattered so much.

Too soon, and too chaotic

Seven weeks after the flood, four different teams were at work, and the surface had barely been scratched. An Army Corps map counted 52 breaches across the region. Communication lines were still down, breaches needed to be plugged, and roads were impassable. As Sandy Rosenthal later wrote, “it would be many years before all the facts were laid out for everyone to see.”

That did not stop people from drawing conclusions. And the first investigators to arrive were, like everyone else, working with incomplete — and in some cases incorrect — information.

The seven studies

1. Independent Levee Investigation Team (ILIT), June 2006. Funded by the National Science Foundation and led by Raymond Seed, Robert Bea and J. David Rogers, this was the first major study. It found a large number of engineering errors and poor judgments. It also concluded — wrongly — that the levees failed partly because of the Orleans Levee Board’s objections to gates at the mouths of the drainage canals. That conclusion would be retracted.

2. Team Louisiana, March 2007. Louisiana’s Department of Transportation and Development selected the deputy director of the LSU Hurricane Center, Ivor van Heerden, to lead an investigation. He had a budget of $130,000; the McKnight Foundation added $250,000, which allowed the team to examine some of the Army Corps’ modeling in detail. Dr. van Heerden might be the first person to suggest that the Army Corps was not being entirely honest with the public.

3. American Society of Civil Engineers External Review Panel, June 2007. The Chief of Engineers asked the ASCE to review the Corps’ own study. The panel’s concise 82-page report, The New Orleans Hurricane Protection System: What Went Wrong and Why, is easily digestible for laypersons. It concluded that the majority of the flooding was due to the levees failing, and that New Orleans residents’ pre-Katrina risk was 1,000 times higher than what is considered minimally acceptable for a major U.S. dam. (The press release that accompanied it was another matter — see Words matter.)

4. Decision-Making Chronology, March 2008. Water experts Douglas Woolley and Leonard Shabman’s 333-page report explains in detail why the levee protection was built as it was. It had more time and resources than the earlier studies. Two key points are in the report but not in its executive summary: the Corps itself selected the high walls plan for the 17th Street Canal, and the Corps made a mistake in the 1980s when it chose to shorten the steel sheet pilings. Levees.org calls it the preeminent report on the flooding.

5. National Academy of Sciences, April 2009. The NAS reviewed the Corps’ 7,500-page draft final report. Perhaps most interesting in its report is its complete lack of any discussion of the local New Orleans levee board.

6. Interagency Performance Evaluation Task Force (IPET), final report June 2009. The Army Corps convened and managed this investigation of its own system. It is thorough, and it admits that the hurricane protection did not perform as designed. The Corps’ commander called the levee protection “a system in name only.” In 2019, the Army Corps quietly removed the IPET report from its website. Levees.org hosts it.

7. Water Policy, 2015. A watershed paper by J. David Rogers, G. Paul Kemp, H.J. Bosworth Jr. and Raymond Seed, discussed below.

The problem with a self-study

Levees.org argued from the start that the nation deserved a truly independent analysis. The official investigation, IPET, was managed by the U.S. Army Corps of Engineers, the same agency responsible for the flood protection’s performance — a clear conflict of interest. ILIT and Team Louisiana reached conclusions that conflicted with IPET on five of seven major levee failure mechanisms, including at the Industrial Canal. And a task force led by retired Congressman Sherwood Boehlert faulted the organization that peer-reviewed IPET for conflicts of interest, lack of transparency and questionable funding sources.

The levees are too important, and what happened when they failed too horrible for us to rely on a self-study.— Levees.org, on the 8/29 Investigation

In 2007, Levees.org launched its campaign for the 8/29 Investigation Act, an independent review of the flood protection failures and the decision making that led to them, modeled on a bipartisan co-chairmanship. Levees.org wrote the legislation with bipartisan input from Senator David Vitter. It would have cost about $5 million — one-tenth of one percent of the money set aside to rebuild the flood protection — and taken about a year. Backed by broad local support, including the New Orleans City Council, parish councils, chambers of commerce, environmental groups and the Southeast Louisiana Flood Protection Authority-East, Levees.org convinced the congressional delegation to file the bill in the House and Senate. It failed to get enough national support.

The price of speaking up

Some of the scientists who criticized the Corps paid for it. In April 2009, LSU fired Ivor van Heerden, the leader of Team Louisiana. Levees.org rallied in protest and delivered more than 4,000 petition signatures to the LSU chancellor. Dr. van Heerden sued for wrongful termination; the American Association of University Professors investigated and censured LSU; and in 2013, LSU settled after spending nearly $1 million fighting him.

Robert Bea, who testified on behalf of flood victims, was the target of a 62-page federal motion describing his opinions as “guesswork.” Judge Duval denied it.

A rare and courageous correction

In February 2013, Levees.org realized that the only civil engineers who blamed local New Orleans officials for the flooding were the authors of the very first levee investigation — a report completed on a shoestring budget, mere months after the disaster, and without the benefit of the later major studies.

New details had emerged. As Pulitzer Prize winner Mark Schleifstein reported, immediately after the flood, Drs. Seed and Rogers had been told by “various members of the corps New Orleans district” that the design of the 17th Street and London Avenue Canals was “forced” on the Army Corps against its will. That information was wrong.

Levees.org spoke with the authors, and together they decided to write a new journal article. The resulting paper, published in Water Policy, the official journal of the World Water Council, retracts the wrong conclusions of the 2006 ILIT report and replaces them with the full and true details:

The corps misinterpreted the study’s findings, concluding that sheet piling that extended deeper would not significantly increase the stability of the I-walls under the short-term loading conditions during a hurricane, meaning the amount of time high water would be on the wall would likely only be a few hours. — Water Policy, 2015, as reported by Levees.org

The paper also reconfirmed that responsibility for the infamous annual “drive-by levee inspections” belonged solely to the Corps — and that they were irrelevant to the failures anyway. The paper is a “one stop shop” addressing most, if not all, of the significant issues relating to the cause of the 2005 flooding.

On May 24, 2015, the New York Times ran an above-the-fold Sunday story: “Decade After Katrina, Pointing Finger More Firmly at Army Corps.” After it appeared, major media largely stopped blaming local officials for the flooding and laid blame where it belonged.

Dr. Rogers passed away a few days before the 20th anniversary of the levee breaches. On May 16, 2026, Levees.org hosted the inaugural J. David Rogers Day at the Levee Exhibit Hall & Garden to honor the engineer who put his career on the line to correct the historical record.

He was a great man who did something that few people, especially someone of his national stature, do. He admitted a mistake, and corrected it publicly. — Sandy Rosenthal, November 2025

The engineers had their say. Next, the courts.