GEOMORPHIC ANALYSIS OF BEACH MORPHOLOGY IN RELATION TO SUBSTRATE, VEGETATION, AND EROSION HISTORY, GALLEON FISH SANCTUARY, ST. ELIZABETH, JAMAICA

Shoreline erosion is a problem around the world that is getting worse as sea level rises and growing populations expand into coastal areas. It is important to identify areas at the most risk for shoreline erosion so environmental planners will have the knowledge and time to mitigate potential resource losses. This is particularly important for coastal communities in poor countries that rely on coastal and marine resources for their livelihoods. This study assesses shoreline form and composition to evaluate the effects of sea level rise and shoreline erosion. These effects influence the quality of natural resources and access to land areas along the 6 km shoreline of Galleon Fish Sanctuary in Black Bay, St. Elizabeth Parish, along the south coast of Jamaica. The shoreline of the sanctuary is composed of mangrove forests, sand beaches, and coral reefs. While beach erosion rates have been reported for this area based on remote sensing analysis, this study provides new information about the relationships among beach topography, vegetation, and substrate and long-term shoreline erosion rates. Beach erosion rates at Galleon have averaged 0.21 m/yr and ranged from -1.9 to 1.13 m/yr from 2004-2012, as reported by Zelzer (2015). Beach profiles and other geomorphic characteristics were measured at 27 sites. Eroding beaches are more likely to have beach scarps, over wash fan deposits, and toppled vegetation. Stable beaches tend to be narrower between the berm and water line and have low beach angles. The presence of mangroves within 10 m of the berm is associated with erosional beaches, which is likely due to the retreat of the shoreline into the mangroves in areas where erosion rates are the highest. The results will be used to make recommendations for conservation monitoring and management goals. Results of this study will be shared with local organizations that manage the sanctuary to help them develop plans to better protect vulnerable resources and coastal areas.