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US Army Corps of Engineers BUILDING STRONG ® Overview of Risk Approach to Manage USACE Dam and Levee Safety Program The Reality of Risk: Dam Safety in the 21 st Century Session Douglas Boyer, PE, CEG Chief, Western Division Risk Management Center Institute for Water Resources February 19, 2013
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BUILDING STRONG ® Corps Dam Safety Portfolio Corps owns 704 dams, Nationwide and in P.R. ► embankment = 86 % ► concrete = 7 % ► combination = 7 % Project purposes include: flood control, navigation, hydropower, water supply, fish & wildlife conservation, recreation Median height: 93 feet Mean height: 112 feet Average age: 53 years High Hazard dams: 77 % Total storage capacity: 331 Million Ac-ft
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BUILDING STRONG ® Traditional Dam Safety Approach Standard engineering analyses Conservative inputs Factor of safety “check the box” Standard design criteria ► Probable Maximum Flood (PMF) ► Maximum Credible Earthquake (MCE) Expensive designs and repairs 3
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BUILDING STRONG ® Investment Comparison
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BUILDING STRONG ® Given Dams needing repair – approx. 300 Annual budget - $500 M Public trust responsibility, accountability, and transparency Range of project benefits and value 5
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BUILDING STRONG ® The Question Which dams to work on first? 6
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BUILDING STRONG ® Risk Analysis Provides a systematic approach to decision- making that enhances the scientific basis of USACE decisions and comprises three tasks: Risk assessment Risk management Risk communication 7
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BUILDING STRONG ® Risk Assessment What can go wrong? How can it happen? What is the likelihood? What are the consequences? 8
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BUILDING STRONG ® Risk Management What is the problem? What can be done to reduce the likelihood or severity of the risk described? What are the tradeoffs in terms of costs, benefits, and risks among the available options both now and in the future? What is the best way to address the described risk? 9
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BUILDING STRONG ® Risk Communication Why are we communicating? Who is our audience? What do we want to learn from our audience? What do they want to know? What do we want to get across? How will we communicate? How will we listen? How will we respond? 10
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BUILDING STRONG ® Answers Other Questions Urgency of modification What to modify Extent/magnitude of modification 11
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BUILDING STRONG ® Risk Identification of potential failure modes Decomposition of failure process Qualitative or quantitative estimates of likelihood of events Comparison of result to a standard 12
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BUILDING STRONG ® Internal Erosion PFM Event Tree 13
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BUILDING STRONG ®
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Risk Reduction
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BUILDING STRONG ® Cumulative Risk Reduction
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BUILDING STRONG ® Change in Dam Safety Focus 17
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BUILDING STRONG ® Change in Dam Safety Focus 18
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BUILDING STRONG ® Principles of Risk Informed Approaches No simple numerical solutions – decisions are informed, not based, on risk Risk compliments, does not replace, traditional engineering standards or experience Credible way to treat uncertainty Periodic and Continuing Risk is integral, not “bolt on”, to our profession
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BUILDING STRONG ® Benefits of PFMA/Risk Approach Multidisciplinary Team ► Civil Engineers ► Other Engineers ► Geologists ► O&M personnel 20 Wow, I never thought about it that way before!
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BUILDING STRONG ® Benefits of PFMA/Risk Approach Instills a culture of creative thinking Why is this important? 21
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BUILDING STRONG ® Benefits of Risk-Informed Decision-Making Better Understanding of Potential Failure Modes Identifying Previously Unidentified Potential Failure Modes Considering the Probability of Failure & Consequences Comparing the Risk of Different Dams Understanding the Uncertainty in Analyses Comparing the Contribution of All Failure Modes to the Overall Risk 22
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BUILDING STRONG ® Challenges Same/similar engineering knowledge – just a different approach and focus Training in risk concepts and principles A tendency to focus on the “number” rather than ‘building the case’ Lack of risk experience 23
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BUILDING STRONG ® Photograph from inundated area downstream of Teton Dam, Idaho (1976)
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