Application of PFMA in Dam Safety: On-Demand

Failure mode evaluation, or what is now more commonly referred to as potential failure mode analysis (PFMA) for dam safety, has become routine practice for many in the profession. The process became more formally organized by the US Bureau of Reclamation in the early to mid 1990’s and gained wider industry exposure in the early 2000’s through the publication of FERC’s Engineering Guidelines, Chapter 14 – Dam Safety Performance Monitoring Program. The PFMA process systematically identifies, describes, and evaluates ways a dam and its appurtenances could fail under all postulated loading conditions. However, a PFMA is much more than an exercise to evaluate and document potential failure modes for a dam. At its fullest extent, a PFMA is a valuable tool which can be used to guide and inform dam safety personnel on where to focus dam safety observations and inspections, where to strategically perform an investigation or install instruments to monitor dam performance, and can be used as a first step in a risk analysis. The process and results of the PFMA can also help to identify and prioritize O&M deficiencies, identify the need for improved operational processes, and pinpoint training needs. PFMAs can benefit dam owners and regulators by providing a better understanding and appreciation of potential structural and operational weaknesses and operating procedures. Finally, they may also be used to better inform downstream emergency management personnel of the hazards posed by the dam, while also providing a better understanding of effective evacuation protocols.