Reclamation’s Approach to Construction Risk Analysis and Risk Assessment

An important distinction between some of the different types of risk analyses performed in the dam safety setting involves the time frame over which the inputs and results are considered meaningful. A risk analysis completed at the periodic review or issue evaluation level is typically focused on long-term conditions; that is, on the risk posed by the facility if it continues to be operated in its current configuration. In contrast, a construction risk analysis would be focused on temporary or short-term conditions. Long-term risks are often viewed as “involuntary” in the sense that they arose from decisions made by previous generations of designers and decision makers. However, when a facility is modified, we are voluntarily changing some element of the inherited design or mode of operation, and temporarily assuming control over the risks posed by the facility. In this context, the risk portrayal chart visual guidelines are not necessarily informative, and the typical approach used for the evaluation of long-term risks does not apply. This paper describes Reclamation’s approach to construction risk assessment, including how our views on the topic have evolved, what we believe is essential to consider, and examples from recent construction risk analyses. Specifically, it explains why Reclamation is no longer using quantitative risk analysis in the temporary risk context, and discusses the advantages of a methodology focused on the identification and mitigation of key threats.