The South Carolina deluge: lessons from a watershed disaster

On October 4, 2015, the Midlands area of South Carolina (centered on metro Columbia and encompassing the counties of Richland, Lexington, and portions of Fairfield) received between 17 and 24 inches of rain in less than a 24-hour period. Other regions of the state received amounts from 6 to 15 inches within the same period. This intense precipitation was preceded by several weeks of above average rainfall. The deluge on October 4 landed on already saturated soils, and riverine systems (i.e., reservoirs, lakes, impoundments, and their watershed networks) that were near or at capacity. The result was overtopping, dam failures, and historic flooding that damaged and disrupted critical infrastructure across the region, inundated 160,000 homes, and led to the loss of 19 lives.

In the fall of 2015, Dr. Stephen Flynn, Director of the Center for Resilience Studies, identified an initial team with expertise in infrastructure resilience, community resilience, and water and transportation infrastructure engineering to study the October 2015 South Carolina historic flooding. In addition, Dr. Flynn reached out to Dr. Susan Cutter, Director of the University of South Carolina Hazards & Vulnerability Research Institute, to assist in analyzing and understanding the event. In a series of field visits to the region, culminating with a major workshop in Columbia, SC in June 2016 (see Appendix A), he and his team conducted extensive agency and individual interviews, and developed a set of lessons that are readily transferrable to other jurisdictions that share a similar risk of watershed disasters.