HURRICANE IMPACTS ON A SWASH-ZONE SAND COLUMN IN LONG BAY, SOUTH CAROLINA

Sandy shores play an important role in the economic and ecological health of much of the eastern seaboard of the United States. Evaluating their state and vulnerability to external impacts requires an understanding of interdisciplinary baseline conditions which, in turn, allows more precise investigations into processes underlying and dictating those conditions, and the effects of human activities and natural disturbance events. This study reports cross-disciplinary characteristics within the top meter of the swash-zone sandy column at a monthly time-series monitoring site immediately before and after three hurricane events. The site is Waties Island, the northernmost barrier island in South Carolina and a part of the Anne Tilghman Boyce Coastal Reserve. The swash zone sand biogeochemistry at this site has been monitored on a monthly basis since November of 2016. The three hurricane events investigated are Irma (2017), Florence (2018) and Dorian (2019). The characterization of the sand column and overlying water is achieved using physical (e.g., permeability, porosity), geological (e.g., grain size and surface area, sedimentary composition), chemical (e.g., oxygen, nitrogen, phosphorus) and biological (e.g., organic matter, chlorophyll a) properties. Changes in these properties are set against the nature of the hurricane impact, e.g., surge (sediment transport and flushing) vs freshwater inputs, and highlight the importance of baseline information in attributing them to episodic natural disturbance phenomena such as hurricanes.