Disaster Management News: Louisiana
March 21, 2007
Photo: Operation Repair began immediately after emergency workers succeeded in closing a massive hole in a floodwall partially swept away by raging Katrina.
Decades of mistakes — some as basic as 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 yesterday concludes. 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." Additionally, 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. The corps also should have known two canals would fail when water levels reached 10 feet. "A back-of-the-envelope calculation" would have alerted engineers to a problem with one of the canals, and a soil strength analysis available since the 1950s would have highlighted flaws in the other. Almost all the problems could have been avoided if independent engineers had reviewed the corps' plans before construction started. Before Katrina struck, the team leader said he and his students had found sagging levees. "My students had tried to get assessments from the corps. The statements were, 'These were federal levees built to federal standards and they're not going to fail.'"
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