Kingsley Dam Incident (Nebraska, 1972)

In September 2015, the Association of State Dam Safety Officials (ASDSO), in cooperation with the Federal Emergency Management Agency (FEMA), released the Lessons Learned from Dam Incidents and Failures website (DamFailures.org). The primary goal of this website is to convey educational information relating to and resulting from dam failures and incidents in an innovative, user-friendly manner. Since its release, over 600,000 users worldwide have accessed the site to learn more about dam engineering and design practices, human factors as they relate to dam incidents, emergency planning and response, operation and maintenance, and other dam safety topics. As part of the ASDSO Dam Failures and Incidents Committee, the DamFailures.org Subcommittee currently oversees maintenance and development of the website. Thanks to continued FEMA funding, the website content is being significantly expanded and diversified. This session will consist of a brief update on new content on ASDSO’s DamFailures.org website. This will be followed by presentations about case studies from the website that highlight unique factors that have contributed to embankment failures and near-failures (e.g., wind, construction methods, and human factors). The potential for sudden formation of natural dam embankments due to landslides, avalanches, or ice jams will also be addressed. This case study examines the wave erosion incident at Kingsley Dam in May 1972. The event was characterized by sustained wind speeds of 30 to 40 miles per hour over a 16-hour period at the dam, resulting in wave heights of 8 feet on the reservoir. The wave action caused substantial erosion of the dam’s upstream slope and led to the undermining and failure of approximately 440 feet of the dam’s concrete parapet. Although the dam ultimately did not fail, concerns about its stability prompted the evacuation of downstream residents. The incident demonstrates the severe damage that wind-driven waves can inflict on an earthen embankment over a relatively short period of time.