DETERMINING THE IMPACT OF SEDIMENT PROPERTIES ON RATES OF GEOMORPHIC CHANGE: LITTLE CUMBERLAND ISLAND, GA

Residents of Little Cumberland Island, GA have witnessed dynamic beach morphology changes over the past several decades which threatens property and habitats. Most sections of the beach are eroding rapidly (5m/year), but others have visible accretion and prograding dune systems. To determine modern rates of erosion and accretion, cross-shore elevation surveys were conducted every 1-2 months starting in September 2022. To determine the impact of sediment composition, grain size, angularity, and organic matter content on erosion rates, surface sediment samples were collected along the transects. Portions of samples were weighed and burned in a muffle furnace to calculate the mass percent of volatile organic compounds. Remaining sample portions were microscopically analyzed for physical properties. These qualities were correlated with morphology rate of change. Quantifying the relationship between physical properties, organic matter content, and erosion rates can aid in future projections of island morphology when considered with the impacts of sea-level rise, human development, and natural island migration.