Southeastern Section–55th Annual Meeting (23–24 March 2006)

Paper No. 12
Presentation Time: 5:10 PM

LANDSLIDE HAZARDS AND LANDSLIDE HAZARD MAPPING IN NORTH CAROLINA


WOOTEN, Richard M.1, LATHAM, Rebecca S.1, WITT, Anne C.1, REID, Jeffrey C.2 and FUEMMELER, Stephen J.3, (1)North Carolina Geological Survey, 2090 U.S. Highway 70, Swannanoa, NC 28778, (2)North Carolina Geological Survey, 1612 Mail Service Center, Raleigh, NC 27699-1612, (3)North Carolina Geological Survey, 2090 U.S. Highway 70, Swannanoa, NC 28788, Rick.Wooten@ncdenr.gov

In September 2004, intense rainfall from the remnants of Hurricanes Frances and Ivan triggered at least 130 landslides that caused five deaths, destroyed 27 homes, and disrupted transportation corridors throughout western North Carolina. These recurring back-to-back storms, and other high intensity rainfall events trigger debris flows and other types of landslides in western N.C. Increased development on mountain slopes in western N.C. exposes more people to landslide hazards. Landslides occur on undisturbed slopes, but if not carefully done, excavations, embankments, and disturbed natural drainage patterns can destabilize steep slopes.

Since September 2004 the National Weather Service, the NCGS, the N.C. Division of Emergency Management and the U.S. Geological Survey have coordinated to develop criteria for issuing landslide advisories for certain weather conditions. In February 2005, the N.C. General Assembly passed the Hurricane Recovery Act of 2005 that provided funding for the NCGS to begin a landslide hazard mapping program for nineteen western N.C. counties. This program includes GIS (geographic information system) and GPS (global positioning satellite)-based landslide database and landslide susceptibility modeling to help delineate areas of high, moderate, and low landslide hazards. High-resolution LiDAR (light detection and ranging) topographic data will be an important aspect of the landslide hazard mapping for GIS-based debris flow susceptibility modeling and for identifying areas of past landslide activity. Landslide hazard maps will be provided to county and local governments to help guide informed decisions on development. Landslide hazard information will also available via the Internet. Coordination with state and local governments and other agencies will be an important part of the landslide hazard mapping program. Completion of a pilot study in Macon County, the location of the September 16, 2004 Peeks Creek debris flow, is scheduled for April 2006.