The Virginia Department of Conservation and Recreation, Division of Dam Safety (DCR) and Schnabel Engineering worked together to perform screening-level risk assessments (SLRAs) and prioritize a portfolio of high hazard potential dams that meet the eligibility requirements for the FEMA High Hazard Potential Dam (HHPD) Grant Program. The study aimed to improve understanding of the risks associated with the aging dams and to prioritize project funding based on relative estimated risk across the portfolio.
The FEMA Project Prioritization Tool (FEMA PPT) was leveraged as the framework to complete the SLRAs. The FEMA PPT estimates order of magnitude risk of inundation as a function of the population at risk (PAR) and annualized probability of failure (APF) for static, hydrologic, and seismic loading conditions. The team surveyed dam owners and reviewed records available in DCR's Dam Safety Inventory System (DSIS), including inspection reports, design and construction documents, and engineering studies, to evaluate the dams. Engineering judgments, approximations, and assumptions were made in a consistent manner to contend with uncertainties due to the limitations of available records.
We will present recommendations and lessons learned for state dam safety programs conducting future SLRAs utilizing the FEMA PPT, a discussion of the opportunity to refine consequence estimates utilizing the USACE Dam Screening Tool (DST) with LifeSim, and how the SLRA results supported the final prioritization and project-funding recommendations.
