The 1928 collapse of the St. Francis Dam is one of the most instructive case studies in civil engineering — not because the failure mode was exotic, but because it exposes how expertise, authority, and confirmation bias combine into catastrophe. William Mulholland, the self-taught engineer who built the Los Angeles Aqueduct, personally inspected new leaks in the dam on the morning of March 12, 1928 and declared it safe. Twelve hours later, roughly 12.4 billion gallons of water tore down the San Francisquito Canyon and killed an estimated 431–600 people.

What makes this failure worth studying is the geotechnical substrate: the dam's abutments rested on the Pelona Schist and a paleomegalandslide of conglomerate that lost cohesion when saturated — a mechanism poorly understood in 1928. The video reportedly walks through the abutment failure sequence, the role of uplift pressures, and why routine leakage observations were misread as normal seepage rather than progressive foundation collapse.

This channel has only 7 subscribers, so production polish may be limited, but the topic itself is a foundational lesson taught in every dam engineering curriculum. It's the disaster that ended Mulholland's career and reshaped how California regulates dam construction — worth watching as a primer on why modern geotechnical review boards exist.