MAPPING MARSH VULNERABILITY TO SEA LEVEL RISE IN KIAWAH ISLAND, SC

Sea-level rise and storm surge can greatly impact the health of salt marshes and present negative impacts on coastal communities. If salt marshes cannot accrete sediment quickly enough or if the marshes’ migration landward is blocked by physical barriers, rising water elevations will cause marsh vegetation to drown and convert to mud flats. These changes would lead to cascading impacts to wildlife within the ecosystem and increase marsh shoreline erosion by reducing the wave buffering effects common in healthy marshes. Studying the progression of marshland vegetation, and the water-mash boundary will provide useful evidence regarding the future status of the marsh. This helps identify areas of vulnerability within the marsh to prioritize wetland vegetation and oyster reef restoration efforts to enhance Kiawah Island’s resilience to natural hazards (i.e., sea-level rise and flooding). Understanding the health and viability of the marsh will enable Kiawah Island’s residents to plan for future flooding scenarios and better protect residents and infrastructure alike.

A database of historic and current shoreline information for Kiawah Island was digitized at a 1:2000 scale from 4-band 1-meter USDA-NAIP imagery from 1977 to 2019. The imagery can be understood as minor development (1977, 1994, 1999) and high development (2006, 2008, 2011, 2013, 2015, 2017, 2019). The digitized marsh edges have been analyzed using the Analyzing Moving Boundaries Using R (AMBUR), a statistical shoreline analysis program. The Shoreline change will be analyzed and include spatial and temporal patterns of shoreline accretion/erosion across the study area. This study will highlight areas most vulnerable to erosion and changing shoreline dynamics. Providing information on the sensitivity of the marsh to SLR and tidal fluctuations.