COASTAL RESILIENCE THROUGH RASTER BASED FLOOD MAPPING AND MODELING: KIAWAH ISLAND, SOUTH CAROLINA

An increase in major flooding events and rising sea levels have left coastal communities vulnerable to inundation and significant damage to property. Kiawah Island, South Carolina has faced numerous accounts of flooding in the past three years and needed to better understand flood risk on the island. Their goals were to learn how storm surge, rainfall, and urban development interact to increase floodwater risk. Using GIS and Lidar data, maps and models for flooding scenarios, including sea level rise and storm surge, have been created to help residents and local government officials to properly prepare for future events.

Planning maps and story maps help provide an organized plans to alleviate impacts from future flooding events. The models for sea level rise and storm surge that will be utilized in this study are being derived directly from the methodology used in National Oceanic and Atmospheric Administration’s (NOAA) Detailed Method for Mapping Sea Level Rise Inundation, and provide literature-supported values for sea level rise and storm surge compared with local tidal ranges of Mean Higher High Water. The resulting “bathtub style” model provides a high resolution rendering of hydrologic connectivity and inundation. All mapping was done in one-meter horizontal resolution, which provides a higher level of detail than NOAA study and Sea Level Rise Viewer, used by many regional coastal communities. Additionally modified CN method rainfall-runoff models have been developed to better understanding of parcel level flood potential and its effect to vital infrastructure. The maps and models developed by the study are being used to help develop policy and guidance for local government moving forward into the future.