THE RIGHT TOOL FOR THE JOB: THE NORTH CAROLINA GEOLOGICAL SURVEY'S LANDSLIDE HAZARD MAPS

During the term of the North Carolina Geological Survey Landslide Hazard Mapping Program from 2005 to 2011, the mapping team created four county-level digital landslide hazard maps for use by the public, local governments, and emergency managers. The purpose of the maps was to provide a planning tool by identifying landslide hazard areas, and to increase awareness of this hazard in western North Carolina. The digital map series was created in a Geographic Information System (GIS), using remote sensing of the LiDAR digital elevation model and aerial photographs, followed by field work to map and collect data at landslide and landslide deposit locations for GIS-based model calibration. This information was then displayed on three map layers – 1) Slope Movements and Slope Movement Deposits layer, showing where landslides and landslide deposits have been mapped, 2) Stability Index Map layer, showing where debris flows might start given 5 inches of recharge in 24 hours and specified ranges of various soil parameters, and 3) Potential Debris Flow Pathways layer, showing where debris flows might travel given these same conditions. To distribute this data to users, the team helped develop a GIS-based online map viewer for Macon, Watauga, and Buncombe counties (http://wfs.enr.state.nc.us/fist/fistMain). Consulting firms, land owners, and local governments continue to use these tools to identify landslide hazards for properties of interest.