This two-part session will focus on understanding the risk of dam failure, with a brief introduction illustrating significant dam failures such as Teton, San Francisquito, Vajont, and Fontenelle. A brief introduction to Bureau of Reclamation dams in the Lower Colorado Region will be presented. Attendees will learn about probable failure modes, quantifying risk and uncertainty, consequences, and overall risk of dam failure. Assessing the overall risk of dam failure includes the process by which overall risk is determined and addresses how risk and uncertainty for specific failure modes play an important role in overall risk assessment. Potential failure modes include failure during normal operations, flood-related failure, and seismic-related failure. Failure during normal operations includes seepage through the embankment, seepage through the foundation, and seepage through the embankment into the foundation. Flood-related failures include failure of the embankment or spillway caused from overtopping, whereas seismic-failure modes include liquefaction or failure of the embankment due to seismic loading. Consequences will be addressed in terms of overall loss of life, followed by an overall risk assessment that couples consequences with risk of failure.
Doug Blatchford, P.E., has 38 years of experience related to water in the West. He joined the Bureau of Reclamation as the Colorado River operations manager, at the Boulder Canyon Operations Office, where he oversaw daily releases of both Davis and Parker Dams and set Hoover Dam energy targets. He supported dam safety by serving as the senior engineer on high hazard dams throughout the West, where he developed risk of dam failure in collaboration with subject-matter experts in design, construction, geotechnical engineering, geological engineering, hydrology, hydraulics, operations, and other facets affecting dam safety.