If Hurricane Katrina, which in 2005 pounded New Orleans and the Delta with surge and heavy rainfall, had followed the same path over the Gulf 50 years ago, the damage would have been less, because more barrier islands and coastal marshes were available then to buffer the city. Early settlers on the barrier islands offshore of the Delta built their homes well back from the beach, and they allowed driftwood to accumulate where it would be covered by sand and beach grasses, forming protective dunes. The beach grasses were essential because they helped stabilize the shores against wind and waves and continued to grow up through additional layers of sand. In contrast to a cement wall, the grasses would recolonize and repair a breach in the dune. (A similar lesson can be taken from the tsunami-damaged areas of the Indian Ocean. Damage was less severe where mangrove forests buffered the shorelines than where the land had been cleared and developed to the shoreline.)
A scientific look at how New Orleans should be rebuilt.
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