Popeye
03-22-2007, 11:18 AM
POSTED: 12:15 p.m. EDT, March 22, 2007
NEW ORLEANS, Louisiana (AP) -- Decades of mistakes -- some as basic as not knowing the elevation of New Orleans -- led the U.S. Army Corps of Engineers to believe its levees and floodwalls would protect the city from a storm as strong as Hurricane Katrina, a report released Wednesday concludes.
The corps used obsolete research to design flood-control structures that were built too low and improperly maintained, a group of engineers and storm researchers called Team Louisiana said in its 475-page report. The report was commissioned by the state Department of Transportation and Development.
The system was intended to be strong enough to handle a Category 3 hurricane like Katrina, which devastated New Orleans when levees broke.
Two major studies last year looked at the engineering problems that caused the 2005 breaches, but the new study also closely examines whether the problems could have been foreseen when the flood-control system was created.
The report said the errors date to the original plans in 1965, which relied on land height measurements from 1929. Because the city had sunk over the years, the plans called for levees that were 1 to 2 feet too low.
"This mistake was locked in" for continuing construction by a policy adopted in 1985, even though scientists knew how fast New Orleans was sinking, the report said. By the time Katrina hit, the levees were as much as 5 feet too low.
The report also said the corps never used a storm surge model released in 1979 by the National Hurricane Center. "If they had, they would have realized that their levee system wasn't high enough for a Category 3 storm at all," said team leader Ivor van Heerden, a Louisiana State University professor, deputy director of the LSU Hurricane Center and a corps critic.
Additionally, he said the corps ignored its own models that suggested that the Mississippi River Gulf Outlet, a navigation channel completed in the early 1960s, would funnel storm surge into St. Bernard Parish and New Orleans.
Engineer: Simple calculation would have revealed flaws
The corps also should have known two canals would fail when water levels reached 10 feet. Van Heerden said that "a back-of-the-envelope calculation" would have alerted engineers to a problem with one of the canals, and that a soil strength analysis available since the 1950s would have highlighted flaws in the other.
The corps was preparing a response, spokesman John Hall said Wednesday.
Van Heerden said almost all the problems could have been avoided if independent engineers had reviewed the corps' plans before construction started.
Before Katrina struck, he said, he and fellow researchers had found sagging levees. He enlisted his students to ask the corps about them, and the agency responded by saying "'These were federal levees built to federal standards and they're not going to fail,"' he said.
The report recommended an independent planning process for hurricane protection, and an independent, bipartisan panel similar to the September 11 Commission to investigate why levees failed. The corps is expected to release a study soon tracing the decision-making process.
Census Bureau: Post-Katrina population still down
Another report this week said the pace of rebuilding after Hurricane Katrina has slowed, leaving New Orleans and some other Gulf Coast areas with less than half the people they had before the storm. And some of the hardest hit might never regain their population, experts say.
The latest Census Bureau estimates, to be released Thursday, say that 10 months after the hurricane, Orleans Parish in Louisiana had slightly less than half the people it did before the storm. Nearby St. Bernard Parish had less than a fourth of its pre-storm population.
The estimates were for July 1, 2006, but experts said few people have moved back since then.
"We're still doing cleanup but not bringing many housing units on line," said Greg Rigamer, a demographer in New Orleans. "We are in the process of rehabbing a lot of properties. It takes time to do that." Rigamer said the Census estimates for the New Orleans area were consistent with his research.
The Census Bureau estimates annual county population totals as of July 1, using local records of births and deaths, IRS records of people moving within the United States and census statistics on immigrants.
NEW ORLEANS, Louisiana (AP) -- Decades of mistakes -- some as basic as not knowing the elevation of New Orleans -- led the U.S. Army Corps of Engineers to believe its levees and floodwalls would protect the city from a storm as strong as Hurricane Katrina, a report released Wednesday concludes.
The corps used obsolete research to design flood-control structures that were built too low and improperly maintained, a group of engineers and storm researchers called Team Louisiana said in its 475-page report. The report was commissioned by the state Department of Transportation and Development.
The system was intended to be strong enough to handle a Category 3 hurricane like Katrina, which devastated New Orleans when levees broke.
Two major studies last year looked at the engineering problems that caused the 2005 breaches, but the new study also closely examines whether the problems could have been foreseen when the flood-control system was created.
The report said the errors date to the original plans in 1965, which relied on land height measurements from 1929. Because the city had sunk over the years, the plans called for levees that were 1 to 2 feet too low.
"This mistake was locked in" for continuing construction by a policy adopted in 1985, even though scientists knew how fast New Orleans was sinking, the report said. By the time Katrina hit, the levees were as much as 5 feet too low.
The report also said the corps never used a storm surge model released in 1979 by the National Hurricane Center. "If they had, they would have realized that their levee system wasn't high enough for a Category 3 storm at all," said team leader Ivor van Heerden, a Louisiana State University professor, deputy director of the LSU Hurricane Center and a corps critic.
Additionally, he said the corps ignored its own models that suggested that the Mississippi River Gulf Outlet, a navigation channel completed in the early 1960s, would funnel storm surge into St. Bernard Parish and New Orleans.
Engineer: Simple calculation would have revealed flaws
The corps also should have known two canals would fail when water levels reached 10 feet. Van Heerden said that "a back-of-the-envelope calculation" would have alerted engineers to a problem with one of the canals, and that a soil strength analysis available since the 1950s would have highlighted flaws in the other.
The corps was preparing a response, spokesman John Hall said Wednesday.
Van Heerden said almost all the problems could have been avoided if independent engineers had reviewed the corps' plans before construction started.
Before Katrina struck, he said, he and fellow researchers had found sagging levees. He enlisted his students to ask the corps about them, and the agency responded by saying "'These were federal levees built to federal standards and they're not going to fail,"' he said.
The report recommended an independent planning process for hurricane protection, and an independent, bipartisan panel similar to the September 11 Commission to investigate why levees failed. The corps is expected to release a study soon tracing the decision-making process.
Census Bureau: Post-Katrina population still down
Another report this week said the pace of rebuilding after Hurricane Katrina has slowed, leaving New Orleans and some other Gulf Coast areas with less than half the people they had before the storm. And some of the hardest hit might never regain their population, experts say.
The latest Census Bureau estimates, to be released Thursday, say that 10 months after the hurricane, Orleans Parish in Louisiana had slightly less than half the people it did before the storm. Nearby St. Bernard Parish had less than a fourth of its pre-storm population.
The estimates were for July 1, 2006, but experts said few people have moved back since then.
"We're still doing cleanup but not bringing many housing units on line," said Greg Rigamer, a demographer in New Orleans. "We are in the process of rehabbing a lot of properties. It takes time to do that." Rigamer said the Census estimates for the New Orleans area were consistent with his research.
The Census Bureau estimates annual county population totals as of July 1, using local records of births and deaths, IRS records of people moving within the United States and census statistics on immigrants.