The St. Francis Dam in California, built by self-taught engineer William Mulholland, was constructed on a defective foundation with the surrounding canyon geology ignored.
Notes on verification
Multiple independent, high-quality sources (Britannica, Smithsonian, Geo-Institute, ASDSO case study) corroborate Mulholland's self-taught background and the failure to conduct adequate geological investigation, leading to the dam's collapse on unstable foundations. [cascade flags: aggregator_dropped_primary_exists | tier=unverified indep_score=0.3 clusters=3 claim_tier=notable] [rescored 2026-09-15: curated origin-host map (PR #65); unclassified hosts no longer scored as aggregators]
Sources
- The Worst: Stupid Engineering Mistakes (seed:technology_and_ai)
- https://www.smithsonianmag.com/history/occasions-i-envy-dead-st-francis-dam-disaster-180954543/ (corroboration)
- https://www.geoinstitute.org/news/jazz-age-geotechnical-engineering-part-6-case-study-st-francis-dam-failure (corroboration)
- https://damfailures.org/case-study/st-francis-dam-california-1928 (corroboration)