Application of PFMA in Dam Safety

Failure mode evaluation or what now is 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.

This training webinar is being taught in two parts.

Part I – Introduction to PFMA – This introductory “how to” session was taught in April, 2014 and is now available in archived format.  Part I covered the basics of what a PFMA is, how it is typically structured, and what information is required.  Examples of potential failure mode sessions and reports were included.  

PART II – Application of PFMA in Dam Safety - This session will focus on what to do with the results of a PFMA.   So you’ve done one.  So what?  This session will discuss how to

• take the results of the PFMA and use them to prepare for and perform more effective dam safety inspections;
• justify (or not) additional explorations;
• determine if existing instrumentation and monitoring systems are appropriate;
• review design documents to assess whether potential dam safety modifications will address the deficiencies and whether the potential modifications might trigger other potential adverse dam safety issues or failure modes;
• identify O&M issues, inadequate operations procedures, and staff training deficiencies;
• inform downstream emergency management personnel of the hazards that the dam poses to the downstream communities and to provide a better understanding of more effective evacuation protocols;

Examples will be provided of how the results of a PFMA can be integrated into everyday dam safety processes and how they can be used to inform and improve dam safety activities and decision-making.