COMPARATIVE SEDIMENTOLOGICAL AND GEOMORPHIC ANALYSIS OF SANTA ROSA ISLAND, FLORIDA - PRE-MAJOR HURRICANE IMPACTS OF 2004-2005 AND POST-DECADAL RECOVERY

Fort Pickens State Park, located on the western end of Santa Rosa Island, Florida, was devastated by hurricanes Ivan (2004) and Dennis (2005). Santa Rosa experienced shoreline retreat, severe dune erosion, and in some locations, significant wash-over due to the successive hurricanes. Two sets of transect data were collected from Fort Pickens 1) by UTC students in 2003 before Ivan and Dennis, and 2) in 2014 by the student author. Comparative analysis of transect data and aerial photographs suggests that initially the location of coastal geomorphic features and stabilizing vegetation migrated with the shoreline and reestablished in more inner island locations relative to the shorelines of the bay and gulf. This may be due to a variety of factors. One factor is anthropogenic - two asphalt roads on the gulf side dictate the location of the foredune and backdune, forcing these features to compress. The bay side now boasts a 65-meter long backshore and adjacent steep dune complex encountered along the 2014 transect, though it has moved 10 meters west. The first major dune is located ~20 meters from the shore on the bay side, and contains a feature resembling a bay-side blowout within the dune. Grain-size analyses reveal sorting and size distributions have recovered to pre-storm distribution for the majority of features encountered along the 2003 transect, though the features shifted to new locations. The grain sizes documented in the later transect follow the same pre-hurricane trend, but vary in width of occurrence. Along with higher elevation dunes, which developed since the 2004-5 storms, the inner-island freshwater lens and marshy area has increased in size; vegetation has flourished.