The South Fork Dam Breach and Johnstown Flood of 1889: A Civil and Dam Engineering History of the USA’s Deadliest Dam Failure: Agenda

The South Fork Dam Breach and Johnstown Flood of 1889: A Civil and Dam Engineering History of the USA’s Deadliest Dam Failure: Agenda

May 13, 2025
12:00 PM - 2:00 PM Eastern 

  • Topic overview
  • The Western Reservoir and its dam 
    • Transportation through the Allegheny Mtns. – the Main Line of Public Works.
    • 1830s: Engineering design of the Western Reservoir and dam.
    • 1840s: Constructing the Western Reservoir and dam: Delays, obstacles, and techniques.
    • The finished Western Reservoir and dam – engineering features.
    • Obsolescence, 1862 breach, and abandonment of the Western Reservoir and dam.
  • Lake Conemaugh and the South Fork Dam 
    • The South Fork Fishing and Hunting Club – captains of industry.
    • The Club’s problem-ridden reconstruction of the dam.
    • The Club ignores engineers’ warnings and other signs of trouble.
    • A tale of two settings – the Club (wealthy) and Johnstown (industrial town).
    • Persistent problems in Johnstown and at the dam.
  • Q&A Session 1 
  • Disaster strikes the South Fork Dam – May 31st, 1889 
    • Overnight storm fills Lake Conemaugh; dam begins overtopping.
    • Warnings of imminent disaster go largely unheeded.
    • Geotechnical phases of overtopping failures in cohesive embankments.
    • Phases clearly reflected by eyewitness accounts from dam.
    • The dam fails – smaller initial breach followed by huge, dramatic final breach.
  • Geotechnical mechanisms of South Fork Dam breach 
    • Most likely mechanism: Sliding induced by overtopping.
  • The Johnstown Flood 
    • Technical vs. human aspects of how disaster played out.
    • Mechanics of the flood.
    • Stories from survivors.
    • The flood reaches and obliterates Johnstown.
    • Debris jam and fire at the Stone Bridge.
  • Q&A Session 2 
  • The flood’s aftermath 
    • Cost in lives and property damage.
    • Relief efforts and journalistic coverage.
    • Public outrage – “Something must be done.”
    • Lack of tangible results; Gilded Age elites protected their own.
  • ASCE report on the South Fork Dam – Delay and probable whitewash 
    • Report written swiftly, but release was delayed.
    • Clear signs of tampering and willful ignorance.
    • Likely influence of Club on report.
  • Changes since 1889 
    • Civil engineering – Licensure/regulation laws and dawn of dam safety groups.
    • Civil engineering – Birth of geotechnics and emergence of dam engineering.
    • Civil engineering – ASCE Code of Ethics.
    • Johnstown – Initial reluctance to acknowledge dam history.
    • Johnstown – Embrace of dam engineering and books on flood (McCullough, Coleman).
    • Johnstown – Post-industrial struggles.
    • US and world – State of infrastructure and possibility of disasters like Johnstown Flood.
  • Conclusion and main takeaways 
    • Dam (and civil) engineering decisions must be based primarily on technical factors, not business or managerial considerations.
    • The standard of care memorializes previous failures and must be diligently followed.
    • The human impacts of dam/civil engineering failures can far outweigh those of successes in these fields.
    • The demands of conscience must always supplement and buttress the dictates of law.
    • Lessons vividly underscored by visiting the Johnstown Flood National Memorial and seeing the South Fork Dam remnants.
  • Acknowledgments
  • Q&A Session 3