Managing Dam Safety Across South Carolina

*Note: On July 1, 2024, The agency formally called the South Carolina Department of Health and Envi­ron­men­tal Control (SC DHEC) split into two separate agencies: South Carolina Department of Envi­ron­men­tal Services (SC DES) and the SC Department of Public Health (SC DPH).

South Carolina faced an unprece­dented envi­ron­men­tal disaster in October 2015. The remnants of Hurricane Joaquin unleashed 16 to 24 inches of rain across the state in just 18 hours, leading to widespread flooding and cata­strophic dam failures. Thirty-four dams were breached, and the South Carolina Department of Health and Envi­ron­men­tal Control (SC DHEC) ordered 76 more reservoirs to be drained immediately. The state’s Dam Safety group encountered challenges due to outdated systems, budget limitations, and a shortage of in-house expertise, making it difficult to respond quickly to the urgent need for dam reha­bil­i­ta­tion, upgrades, replace­ments or decom­mis­sion­ing. SC DHEC made a point to address the situation swiftly and improve infra­struc­ture for the future.

SC DHEC turned to outside support to strengthen its Dam Safety Program, engaging CDM Smith’s team in August 2016 to serve as an extension of SC DHEC staff to tackle the challenges of the state’s aging dam infra­struc­ture.

One of the team’s main tasks was to create inundation maps for up to 650 dams that were essential for identifying downstream hazards and evacuation zones as part of Emergency Action Plans (EAPs). Addi­tion­ally, the team conducted visual inspections on 2,000 dams across South Carolina, evaluating key elements like crests, slopes, spillways, and outlet works. They also performed downstream structure checks where inundation mapping was completed. Later on in the program, CDM Smith assisted in performing and checking inundation mapping for all state-regulated dams (more than 2,200 dams) using DSS-WISE Lite.

The team has reviewed permit appli­ca­tions, plans, spec­i­fi­ca­tions, and studies, providing technical feedback to SC DHEC to ensure safety and compliance. Once work was completed under these permits, the CDM Smith team reviewed Notices of Completion, as-built plans, conducted site visits, and assisted with preparation of Certifi­cates of Completion.

One significant hurdle was the decom­mis­sion­ing of three state-action dams—Mandel Park Pond Dam in Hopkins, Wesley North Pond Dam in West Pelzer, and Upper North Lake Dam in Greenwood. The team worked with dam owners when they were unable or unwilling to meet the decom­mis­sion­ing require­ments, ensuring these projects were completed safely and met regulatory standards.

Today, SC DHEC is able to manage the state’s Dam Safety Program much more effectively. By placing experts directly within SC DHEC, CDM Smith provided hands-on training for SC DHEC engineers and shared valuable knowledge in hydrology, hydraulics, geot­ech­ni­cal, and structural engineering. Using the Department's internal web-based inspection program also streamlined the process, allowing for real-time data entry and quicker report generation.

While the original schedule allowed 15 months for inspections, the team finished the job in just under 12 months—three months ahead of schedule. This success was due to strategic leadership, careful planning and innovative technology appli­ca­tions. The partnership between SC DHEC and CDM Smith has tackled the urgent issues with South Carolina’s aging dams and set the foundation for a more-proactive and sustainable Dam Safety Program.

Since 2018, CDM Smith has conducted numerous inspections, established a risk-based decision-making framework, performed statewide risk analyses, developed data management tools, created guidance documents, provided training, and supported emergency response activities.