Digital Coast In Action
Visualizing Shallow Coastal Flooding and Sea Level Rise in Charleston, South Carolina
Shallow coastal flooding is caused by higher than average tides and can be worsened by heavy rainfall and onshore winds. Understanding the potential area of inundation helps local and state officials better prepare their communities.
The Process
In Charleston, South Carolina, lidar-derived elevation data were used to map inundation. This high-resolution elevation information is one of the best data sets available for predicting the area impacted during tidal and weather-related, short-term coastal flooding, and the impacts of relatively small changes in sea level.
The data were acquired from the NOAA Coastal Services Center website using the lidar data retrieval tool (LDART). LDART was used to process the data into the format needed for the geographic information system (GIS) map visualization. This process is taught in the Coastal Inundation Mapping course.
An abnormally high tide of 2.1 meters (7 feet) was predicted for two dates during the year under study, as depicted by the dark blue areas. A sea level rise of .5 meters (1.6 feet), which may occur over the next 100 years, means the extent of flooding would be much greater (light blue areas) during these abnormally high tides.
Another impact of rising sea level would be an expected increase in frequency of flooding. With a .5 meter sea level rise, the areas currently susceptible to a 2.1 meter tide twice per year would be susceptible to flooding on 289 days—and twice per day on 66 of those days.
Potential inundation from shallow coastal flooding, with and without sea level rise. The map shows the scale of potential flooding, not the exact location, does not account for erosion or subsidence, and assumes no wind, rainfall, or future construction.
View PDF version of this map (Download Adobe Reader)
