In Virginia alone, there are 2,900 dams ranging from farm ponds to large reservoirs providing hydroelectric power and water supply. Approximately 360 of these dams are classified as potentially high hazard where failure would result in probable loss of life or serous economic damage. For dams where potential failure modes have been identified to have an unacceptable level of risk, dam owners are faced with a myriad of choices to address this risk and improve their water infrastructure. These may include structural measures (ex: increasing spillway capacity, toe drain replacement), improved monitoring or warning systems, non-structural measures (ex: purchasing downstream properties), or dam removal.
The presentation will focus on two unique dam risk reduction projects and discuss the hazard and cost-benefit evaluations, planning and permitting, and design process. For the first project, risk reduction is being achieved through lowering the dam, improving hydraulic capacity, and providing additional erosion protection. For the second project, inspections determined several features of the dam were in a state of disrepair and a complete dam removal and upstream restoration was selected as the preferred option. This approach will eliminate dam risk failure and future maintenance.