Oops.
In June, the Army Corps of Engineers proudly announced that new gates and levee repairs meant residents returning to Lakeview and Old Metairie would see floodwaters reduced by up to 5 1/2 feet if the city were hit by a 100-year hurricane.
They were off by 5 feet.
The reason? The Lakeview data got fouled up when somebody put a minus sign in a calculation that called for a plus sign ... The Old Metairie errors stemmed from faulty assumptions about the way water would move into and out of the neighborhood from surrounding areas.
In other words, flood protection in Lakeview and Old Metairie has hardly improved at all since the neighborhoods drowned in the 2005 flood -- despite the public celebrations of corps officials and others in releasing the maps on Hurricane Katrina's second anniversary.
I don't really know what to add to this, except: Knowing the risks of flooding is very important for the future of New Orleans. If homeowners and businesspeople are going to rebuild the city, they need to know as precisely as possible how likely they are to end up under water. With hard information, hard choices can be made with eyes open. The Corps ignored this need for decades before Katrina, providing only bland (and incorrect) assurances about the flood risks.
So when Corps engineers finally embarked on a project to calculate those risks, they needed to get it right. The first time.
For an agency responsible for monumental failures, restoring public confidence is as important as the engineering work itself. The Corps can tout progress building floodgates and moving earth (though this screwup also reveals there's been less progress than we thought), but if it can't figure out what the risks are for people in Lakeview, what's the point?
As seas rise, the Corps will be doing more such assessments for coastal areas from Houston to Manhattan. Their inhabitants should all feel a little more anxious today.
Update: The head spins. The Corps now says that its original estimates were right after all. That's great. What's not great is, again, this whole back-and-forth does not exactly inspire confidence in the Corps's ability to a) assess its own work and b) win the public's confidence.