On March 12, 1928, the St. Francis Dam in San Francisquito Canyon, northwest of Los Angeles, California, collapsed. A torrent of water rushed downstream, killing nearly 500 people and sweeping away thousands of acres of fertile land. The catastrophic failure is considered one of the worst civil engineering failures in the United States. The disaster resulted in updated dam safety legislation to prevent a similar incident from ever occurring again.
In the early 1900s, Los Angeles was experiencing dramatic growth, and William Mulholland, the general manager and chief engineer of the Los Angeles Bureau of Water Works and Supply, wanted to build a dam to regulate water storage. The dam was integral to the Los Angeles Aqueduct system and would create a lake containing 12 billion gallons of water.
Planning began, and by 1925, construction was underway in earnest. On two separate occasions, the dam’s height increased by 10 feet to provide more water storage. However, engineers made no modifications at the base. There were also unmitigated geologic hazards like ground instability and canyon rock, later deemed unsuitable.
On March 12, 1928, about 11 hours before the disaster, Tony Harshelfeger, who lived below the dam, notified Mulholland that muddy water was leaking from the dam’s side. Mulholland and the assistant chief engineer drove to the dam and proclaimed it safe. Shortly before midnight, the concrete walls of the dam collapsed. Survivors recalled hearing a sound like thunder. A 125-foot-high wall of water careened down the canyon, destroying everything in its path and scouring the canyon walls as it raced toward the Pacific. Nearly 24,000 acres of prime land washed away, devastating the local farming industry for years. Harshelfeger, who initially alerted authorities to the leak, drowned.
In the days following the disaster, stories of loss and survival began to emerge. C.H. Hunick, 80, was tossed from his bed as water crashed into his house. He rode the raging current and was close to death when a strong hand reached out and grabbed him. Hunick looked up to discover that the rescuer was his son.
When the wall of water hit the Holsclaw home, it was lifted from its foundation and carried for some distance. The parents survived by clinging to floating debris and trees, but their 12-year-old daughter and baby died.
Thelma McCauley, 16, was sick with measles when flood waters hit her home. The current swept her nine miles downstream, and she spent 12 hours in the water. Rescuers discovered her alive the next day, but she lost her parents and brother.
The death toll from the St. Francis Dam tragedy was estimated at close to 500 but was possibly much higher. Some bodies were never recovered, having been buried deep in silt or washed out to sea. The canyon was also home to many migrant workers whose identities were not known.
Following the disaster, a devastated Mulholland took full responsibility for the failed dam. With his professional career in shambles, he retired months later. Experts conducted hearings, coroner’s inquests, and studies to prevent another tragedy. Lawmakers passed legislation to increase dam safety, and Los Angeles paid more than $7 million in restitution to the victims’ families and affected landowners.
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