The Army Corps of Engineers have just released a study on flooding risks in NOLA due to hypothetical hurricanes.  As it is summarized in the New York Times, the study shows that the risk today is basically equivalent to the pre-Katrina risk — though some areas had improved while others had deteriorated.

The article and study make for interesting perusal, but I have to say I’m a bit dubious.  Firstly, though the jury is still out, the concept of a “1 in 100 year storm” &c may be a rapidly moving target due to global warming, making a Katrina-strength storm much more likely in the future than it was in the past.  The science isn’t there for us to know how climate change will effect hurricanes, but I’m afraid that by the time we have a conclusive model it will be far too late.  This is especially relevant as much of the improvement in flood protection seems targeted at the 1-in-100 storms, leaving the 1-in-400 flood risks more or less unchanged.

I’m also skeptical about the accuracy of this elevation-based flood modeling, which more or less assumes that water will be spread over the city in nice even layers.  If we learned anything from Katrina, it was that things fail in unpredictable, uneven ways.

My only hope then from this study is that because the insurers will certainly pay attention to it, it has the potential to affect rebuilding patterns.  To date it seems that so many balls have been dropped, and so many opportunities have been missed, that it’s hard to hope that anything sensible will emerge.  Nonetheless, money talks, and if insurers stop funding development in the flood zones there will be some pressure to do the right thing, which is to build sustainable communities on the natural high ground.

Something to say?