| Lessons learned
awareness of dams and their risks to public health, safety, and welfare. In September 2021, the South Carolina section of the American Society of Civil Engineers (ASCE) prepared its first report card on infrastructure. Every four years, ASCE’s Report Card for America’s Infrastructure depicts the condition and performance of American infrastructure in the form of a school report card – assigning letter grades based on the physical condition and needed investments for improvement. South Carolina’s dams received a D grade which means they are poor and at risk. The infrastructure is in poor to fair condition and mostly below standard, with many elements approaching the end of their service life. A large portion of the system exhibits significant deterioration, and condition and capacity are of significant concern with strong risk of failure. South Carolina currently has 2294 state-regulated dams, 90% of which are privately owned and operated. Regulated dams are classified as either high hazard, significant or low hazard potential. High hazard potential dams have the greatest possibility of causing both serious damage to infrastructure and property, but also carry the likely risk of loss of human life in the case of a dam failure. Approximately 25% of dams in South Carolina are under this designation – more than 70% are in satisfactory or fair condition but more than 25% are poor or unsatisfactory. In addition, less than 12% of South Carolina dams are of significant hazard potential and more than 61% are of low hazard potential. South Carolina also has 45 federal dams of which
12 are high hazard. Two of these are in satisfactory condition, four are fair, one is poor, two are in unsatisfactory condition, and three are not yet rated. There is one unrated significant hazard federal dam, plus 32 low hazard potential structures. The average age of South Carolina’s dams is just over 60 years old, higher than the national average of 57 years old. While the age is not a direct reflection of hazard potential, ASCE says the high average age typically means that the dams were not built to current standards and may not incorporate newer materials that could be used to improve their resilience and reduce the risk to downstream areas. Nearly 80% of the existing inventory was constructed before South Carolina lawmakers established a state-wide dam safety framework. Therefore, many of these dams were constructed with little regulatory oversight or proper documentation of construction details. Over the last two decades, South Carolina’s dam safety budget has drastically increased. In 1999, it was slightly over US$250,000, translating into approximately US$100 per regulated dam, while the budget per regulated high hazard structure was around US$1500. After the historic October 2015 rainfall and subsequent dam failures, resources were allocated to rebuild and expand the state’s dam safety programme. Since that time, more than US$12 million has been made available for engineering technical support, dam inspections, inundation mapping, and more. Now, the dam safety budget is more than US$1 million with US$453 being spent per regulated dam and more than US$1900 per HHPD. Though these values have significantly increased, they remain well below the national averages of US$738 per regulated dam and US$4875 per HHPD.
Dam safety staff also increased from less than two fulltime equivalents (FTE) to approximately 18. Accordingly, there was a significant improvement to the number of state-regulated dam safety inspections conducted per staff member. From 2011 to 2018, the number of inspections were driven down from more than 1400 per FTE to approximately 125 per FTE, now better than the national average of 189 per FTE. For HHPD, the value also fell from more than 100 per FTE to nearly 30 per FTE, very close to the national average of 29.
Ideally, all South Carolina’s HHPDs would have
Emergency Action Plans but currently only 72.5% are covered, ten % below the national average. To withstand or quickly recover from localised
storms or non-weather-related events that strain South Carolina’s dams, the staff rotate 24-hour-a-day on-call shifts for the Dam Safety Technical Assistance phone line. The state says it is committed to providing engineering expertise to assist dam owners if trouble arises and to help identify the severity of a situation. This assistance is intended to determine whether local emergency response officials should be notified. To this point, the phone line assistance has enabled staff to respond to multiple occasions of after-hours dam failure emergencies. In addition to providing technical assistance to
ensure the state’s dam sector is becoming more resilient, investment has also been made in innovative modelling to improve safety planning efforts. Although improvements have been made ASCE
recommends that to raise its grade South Carolina needs to: ● Develop emergency action plans for every high hazard-potential dam by 2025.
● Determine sustainable sources of funding for dam rehabilitation, maintenance, and other safety projects
● Increase state funding to the dam safety programme, including adequate staffing and resources per state-regulated and high hazard potential dam that are in line with na-tional averages.
● Educate dam owners about the importance of keeping accurate, easily accessible ownership and operation and maintenance records. ●
Above: Floods in South Carolina in 2015. Historic weather events caused dozens of state- regulated dams to fail © Matthew Orselli
References
https://www.cleanenergycouncil.
org.au/resources/resources-hub/ hydropower-the-backbone-of-a- reliable-renewable-energy-system
https://waterpowerweek.ca/why- diversity-equity-and-inclusion- are-crucial-to-the-future-of- waterpower/
https://damsafety.org/MI-Interim- Report
https://infrastructurereportcard. org/state-item/south-carolina/
www.waterpowermagazine.com | December 2021 | 29
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