EPISODIC EROSION, DISPLACEMENT AND RECOVERY OF A COASTAL FOREDUNE 1994-2001, FIRE ISLAND NATIONAL SEASHORE

Long-term measurement of coastal foredune change and management history at Fire Island National Seashore documents a variety of scales of displacement and recovery. Coastal erosion related to a nearshore circulation cell scarped the coastal foredune causing more than 20 meters of dune crest displacement in 1994. Subsequent detailed field surveys, augmented by 3 LIDAR overflights, provide data for the construction of 3D digital terrain models (DTMs). Comparison of morphological compartments within the DTMs generates spatial characteristics of foredune recovery. Through 2001 recovery of dune form and volume has been achieved throughout the length of the circulation cell. Although the foredune form has recovered nearly to its former dimension, the spatial position of the foredune crest has shifted approximately 20 meters inland. Therefore, the dynamic processes of coastal foredune retention and continuity, applied to management, incorporate episodic erosion, recovery, and inland displacement.