Although category 4 Hurricane Joaquin ultimately tracked far to the east of the United States it resulted in record-shattering rains and flooding across South Carolina. Several areas of South Carolina saw precipitation accumulations exceeding the threshold for a 1-in-1,000-year event from October 1 to 5. The subsequent floods caused inundations throughout the state with areas around Charleston and Columbia hardest-hit and killed 19 people. The damage in South Carolina alone is estimated at $12 billion. This extreme event highlights the potential long range impacts of offshore hurricanes tracking hundreds of kilometers from a coastal landfall. A team from the Geotechnical Extreme Events Reconnaissance (GEER) Association, supported by the National Science Foundation, was mobilized to investigate the impacts of the flooding in South Carolina. The team worked collaboratively with federal, state and local organizations to augment the reconnaissance effort. This report presents the field observations of the GEER team made during the field reconnaissance from October 11 to 14, 2015 in South Carolina’s Richland and Lexington Counties. The study area encompassed the greater and downtown Columbia, the Capital of South Carolina. The coverage includes the dam breaks along the Columbia Canal, the heavily devastated neighborhoods along Gills Creek in Columbia and the Twelvemile Creek in Lexington, but also includes observations along the Saluda dam spillway, the Broad river embankment breach into the Marietta quarry with a destroyed Northfolk Southern Railway bridge and the breach along Lake Elizabeth. In total 52 dams are known to have failed in the historic flooding event. The GEER team visited a dozen dams including 9 breached dams and 2 overtopped dams without a breach.

Contributors: Hermann M. Fritz (Georgia Institute of Technology, Atlanta, GEER team leader); Ronald Andrus (Clemson University, Clemson, SC) ; Alejandro Martinez (University of California Davis, formerly Georgia Tech); Fikret Atalay (Georgia Institute of Technology, Atlanta, GA); Barnabas Bwambale (Clemson University, Clemson SC); Jeremy Varner (Division of Dam Safety and Inspections, FERC); Thomas Bristol (Geosyntec Consultants, Columbia, SC); Brandon Mogan (Geosyntec Consultants, Columbia, SC); Melissa Setz (Geosyntec Consultants, Kennesaw, GA); Robert Bachus (Geosyntec Consultants, Kennesaw, GA); Glenn Rix (Geosyntec Consultants, Kennesaw, GA); Njoroge Wainaina (Geosyntec Consultants, Raleigh, NC)