Report Says Corps Miscalculated on Levees
Thursday, March 22, 2007
The design and construction of the New Orleans hurricane levee system was flawed because the Army Corps of Engineers ignored warnings about the power of potential storms and made critical engineering miscalculations, according to a long-awaited investigative report from a team of Louisiana engineers and scientists.
The "Team Louisiana" report echoed many of the findings of previous engineering inquiries but offered them in sometimes sterner terms, while highlighting some of the political forces that affected the flood system's formation.
Army Corps of Engineers officials appear to have shortchanged the construction of essential flood protection systems to save money, according to the report, while at the same time, under local pressure, expanding the project's reach so that more low-lying land could be developed into new suburbs.
"The problem is that hurricane protection has no lobbyists," said Ivor van Heerden, a hurricane researcher at Louisiana State University, who led the team.
Moreover, while the city was vulnerable to a relatively weak storm, Corps officials offered unsubstantiated assurances to the public that the system could withstand a "1 in 300 year" storm event, or a storm so severe it is likely to happen only once in 300 years, the report said.
In response to the Team Louisiana findings, a Corps spokesman offered a statement saying the agency's own investigative inquiry, completed last year, focused on many of the same engineering issues, and noting that the flood protection system that failed in Hurricane Katrina was shaped by the decisions and actions of many agencies.
"Corps does not agree with any assertion that USACE is solely responsible for the events of Hurricane Katrina," the statement said. "Civil works projects are all authorized by Congress and planned, designed and constructed cooperatively between local, state and federal agencies."
The Team Louisiana report focused on what is known as the "Hurricane Protection System" of the New Orleans area, made up of 125 miles of different types of levees, including earthen levees and concrete canals, pumps, and a drainage works.
The system, authorized by Congress in 1965, cost more than $700 million to build, but its failures in Hurricane Katrina were far-reaching, deadly and at least partially preventable, according to the report:
· While the levee system was supposed to protect against "the most severe meteorological conditions considered reasonably characteristic for that region," Corps engineers disregarded warnings from General Accounting Office (now the Government Accountability Office) testimony and elsewhere that storms could be far more dangerous than what they were planning for.
· Because of a basic data discrepancy regarding sea level, canal walls and levees were built one to two feet lower than they should have been.
· The Corps overestimated the holding strength of local soils in many places, and canal walls sunk into those soils toppled under Katrina's surge.
According to the Corps' own investigation, Katrina caused "50 major breaches" in the system, and three of them were critical, causing about 70 percent of the flooding.
The Corps "now estimates that between $2 billion and $4 billion will actually be required to achieve the minimal 100-year level of protection," the report said. "The level of protection that this will achieve should not be confused with the much higher Category 5 hurricane protection now being studied. . . . That will cost much, much more."