DEVELOPING, MODELING, MAPPING, AND COMMUNICATING FLOOD RISK WITH GIS ACROSS THE SOUTH CAROLINA LOWCOUNTRY

Charleston, South Carolina is one of America’s most vulnerable cities to climate change-driven storm surge and sea level rise. With the majority of residents living within 10 feet of mean sea level and with gravity-based storm water system that becomes impaired during high tide conditions, maps and tools are needed to better understand the nature and magnitude of the flood hazards associated with changing climate conditions are needed.

The LowCountry Hazards Center (LCHC) has been working in together with the South Carolina Sea Grant Consortium (SC-SGC) and the Charleston Resilience Network (CRN) to communicate flood risk through Geo-Aware Apps for use by citizens, and local / regional government. Using empirically-tested methodologies derived from NOAA and the USDA to incorporate high resolution data calibrated to local conditions at a neighborhood-level. The LCHC has created tidal and precipitation-based flood maps for communities across the Lowcountry region. The maps are scaled and linked to tidal gauges allowing models for sea level rise (SLR), storm surge, king tides, or a combination of those drivers and rainfall runoff models where available. Flood severity was communicated with the use of a stakeholder tested “flood disruption scale,” aggregating flood depths at groupings empirically shown to impede both pedestrian and motor vehicle traffic in flood waters. Taking nationally-vetted methodologies and translating them to an area that stakeholders relate most closely to streets and buildings in their community The maps have been used by communities incorporating them into their personal adaptation practices helping to plan for both storm hurricane and future climate induced sea level rise.