Loss of Life Consequence Assessment for Dam Failure Scenarios: Download


• Why do we evaluate loss of life resulting from dam failure?
• How are loss of life estimates used?
• Hazard Classification
• Improve Emergency Action Planning
• Determining individual and societal risk
• A comparison of loss of life from dam failure to loss of life from natural hazards

History of Dam Failure Loss of Life Estimation with Focus on Bureau of Reclamation Involvement
Learning from the Past – Factors that Influenced Loss of Life During Significant U.S. Dam Failures

• 1928 – St. Francis Dam, California (failure at midnight with no warnings issued before failure)
• 1964 – Swift Dam, Montana (no warnings issued before failure)
• 1972 – Buffalo Creek Coal Waste Dam, West Virginia (no warnings issued before failure)
• 1972 – Canyon Lake Dam, South Dakota (failure during an area-wide storm)
• 1976 – Teton Dam, Idaho (failure near noon with warnings issued before dam failure)
• 1977 – Kelly  Barnes Dam, Georgia (no warnings issued before failure)
• 1995 – Timberlake Dam,  Virginia (poor implementation of an Emergency Action Plan)
• 2004 – Big Bay Lake Dam, Mississippi (successful implementation of Emergency Action Plan)

Wayne J. Graham, P.E.

Civil Engineer

Mr. Graham received a M.S. degree in Civil Engineering from Colorado State University, Fort Collins, Colorado.  He worked for the Bureau of Reclamation from 1979 through June 2011.  While at Reclamation, he was responsible for preparing dam failure inundation mapping guidelines, inundation maps, and downstream hazard potential classifications. He is currently working part-time for Reclamation as a rehired annuitant.

Lawn Lake Dam, located north of Denver, Colorado failed in 1982 and piqued an interest in dam failure consequences.  Why do the failures of some dams cause large loss of life while others cause little or no loss of life?  In every event, some things are out of our control, such as the flood severity and when the event occurs, while some things are within our control, such as whether dam failure warnings are issued.  He began researching the factors that influence the loss of life resulting from dam failure.

He has been to the site of several dam accidents or failures including:  Vajont Dam, Italy; Bradford Dam, England; South Fork Dam, Johnstown, Pennsylvania; St. Francis Dam, California; Walnut Grove Dam, Arizona; Mill River Dam, Massachusetts; Buffalo Creek, West Virginia; Kelly Barnes, Georgia; Teton Dam, Idaho; and many others.

In 1999, Mr. Graham authored DSO-99-06, “A Procedure for Estimating Loss of Life Caused by Dam Failure.”  The procedure is useful, robust, easy to apply, and produces plausible results.  This procedure has provided a useful tool as Reclamation uses risk analysis, which evaluates the probability of adverse consequences, as the primary support for dam safety decision-making.

Mr. Graham has made presentations at several ASDSO Annual Conferences.  Two articles that he published in ASDSO’s Journal of Dam Safety would be good background reading. The first article discusses the difficulty in achieving a success evacuation and the second describes a sequence of dam failures that resulted in the largest loss of life every from any dam failure.

“Get Out – Get Out – Get Out!  Getting People Out of Harm’s Way,” Volume 7, Issue 1, 2009.

“The Banqiao and Shimantan Dam Failures: Factors Affecting the Warning and Evacuation Success,” Volume 8, Issue 4, 2010.


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