PRE– AND POST–STORM MORPHOLOGICAL ANALYSIS OF SAND DUNE EFFECTIVENESS AND REGENERATION IN MID–ATLANTIC BARRIER ISLAND SYSTEMS

Dunes are an essential morphological component of barrier islands. First, dunes are an important buffer to storm energy. Second, they are part of the barrier beach ecosystem. The vital importance of sand dunes was underscored during Hurricane Sandy in October 2012. Sandy damaged much of the Mid–Atlantic coastline with a 12 to 14 foot storm surge. There was a clear and dramatic difference––communities that maintained vital and healthy dune systems did not suffer as much damage as those that did not. Our understanding of the importance of dune systems as a storm buffer is not new. Nevertheless, the maintenance of dune systems is a matter of some contention and the real question is why, in the face of long–standing evidence, would coastal communities fail to maintain their dune systems? This project evaluated pre– and post–storm performance of dune systems in three New Jersey barrier island systems: (1) Sandy Hook; (2) Long Beach Island; and (3) Brigantine. I evaluated the status of the dunes at each location before and after Sandy and correlated the level of storm–related damage to the health of the dune system today adjacent to each of three land use types: urban/residential, semi natural/recreational, and natural ecosystem. This study employed the analysis of data from multiple sources: long–term shoreline change rates, digital images and historical aerial photos, and direct ground surveys. The results confirm the notion that healthy dune systems buffered the storm surge and protected development and natural ecosystems. The analysis of pre- and post-storm images clearly indicated that storm damage was severe along unprotected beaches. Those locations now manifest large reconstructed dune systems in response. The results also suggest that the level of natural recovery is largely a function of beach morphology: i.e., the robustness of dune recovery appears to be dependent on the stability of the barrier island. This study confirms that dune systems are an effective, natural alternative to coastal protection and essential to barrier island stability.