Speaker(s): Michael D. Bennett, P.E., Geotechnical Engineer, Gannett Fleming, Inc.
PDH’s: This webinar is eligible for 2 PDH credits
The 1889 breach of the South Fork Dam, which caused the infamous “Johnstown Flood,” remains the deadliest dam failure in US history. The Commonwealth of Pennsylvania built the dam in the mid-1800s as part of a cross-state transportation network, and the dam’s design and construction met the contemporary standard of care. However, decades of neglect left the dam in disrepair until a group of Pittsburgh tycoons hastily rebuilt it during the Gilded Age to create an exclusive lakeside resort. The elites’ repairs were shoddy, but they ignored warnings of disaster. Then, on May 31st, 1889, the dam breached due to overtopping following a 2 percent annual probability (50-year storm) rainstorm. The resulting tsunami-like flood wave inundated the steelmaking community of Johnstown and killed roughly 2,500 people. Outrage over the disaster was widespread, but the well-connected tycoons warded off legal and financial consequences, even compromising ASCE’s investigation of the failure. Civil engineering, dam safety, and engineering ethics have all undergone major positive changes since 1889. Yet, the South Fork Dam story stands as a stark reminder to civil engineers, particularly dam engineers and dam safety professionals, of their duties and responsibilities.
Key Takeaways:
• Understand the long- and short-term causes of the 1889 South Fork Dam breach.
• Reemphasize the importance for engineers of meeting the contemporary standard of care.
• Review how some of the significant developments in dam engineering since 1889 have enormously reduced the likelihood of a dam disaster of similar magnitude occurring today.
• Underscore how dam engineers, civil engineers, and dam safety professionals must consider technical expertise and judgment above all else, especially cost concerns and political considerations, when making design and safety decisions or conducting forensic investigations.