THE NEED FOR EVALUATING THE RELATIVE IMPORTANCE OF GEOMORPHIC FEATURES ON HURRICANE DAMAGE AT THE COAST

Several year's worth of observations made immediately after several hurricanes and winter storms reveal suggest that property damage potential can be lessened significantly by prudent site selection and proper location of structures on property. These studies provide only empirical evidence, however, and comprehensive quantitative evaluation is still lacking.

On the one hand, determining relative hazard ranking of large sections of the coast is relatively straightforward. These are the “lessons learned” from the field studies. Among the most obvious lessons learned are that wide beaches protect property, dunes protect property, vegetation protects property, shore-perpendicular roads act as overwash and storm-surge ebb conduits, notches in dunes create overwash passes, overwash and storm-surge ebb is intensified when funneled by structures, seawalls can protect buildings but they also can cause narrowing of the beach reducing both recreation and storm protection value, setbacks protect, and elevation protects property.

On the other hand, what is lacking is quantification of which factors most closely correlate with less storm damage, and how those correlations vary in different geologic settings. Preliminary statistical studies in Florida (post-Opal), South Carolina (post Hugo), and North Carolina (post-Fran) indicate that along those coasts, site elevation provided the best protection against property damage, followed by dune height (in front of the site) and beach width. These studies, however, were limited to very short stretches of barrier islands, less than a mile in length. What is lacking are studies from mainland coasts, rocky coasts, and a variety of geologic, engineering, and development settings.

We encourage continuing research in this area. Too often after a storm, rebuilding begins anew in the same place and in the same way as before the storm. We must have solid scientific evidence of where to build. Coastal scientists must take the lead and provide guidance for low-risk pre-storm mitigation and post-storm reconstruction plans.