All Library NewsForgotten L.A. history: The deadly St. Francis dam disaster

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Just before midnight on March 12, 1928, the collapse of the St. Francis Dam, a 200-foot high concrete gravity-arch dam in St. Francisquito Canyon occurred, killing over 450 people and leaving a path of destruction 2-miles-wide and 70 miles long. Known as the United States’ worst civil engineering disaster of the 20th century, the dam, located near present day Castaic and Santa Clarita, failed only two years after its completion.

UCLA Library’s Digital Library Program recently digitized glass plate negatives–a medium only in use from the 1850s through the 1920s–from the Los Angeles Times Photographic Collection chronicling the aftermath of this man-made disaster.

The structural and geological reasons for the St. Francis Dam’s failure are attributed to the dam’s poor construction and location on a geologically unstable site, but the social and political forces that pushed for the rapid growth and expansion of the city of Los Angeles can also be understood as the underlying context for the disaster.

Aerial view of the flooded valley after the collapse of the St. Francis Dam, Santa Clara River Valley, CA, 1928. Glass plate negative, Los Angeles Times Photographic Collection, UCLA Library Special Collections.
Aerial view of the flooded valley after the collapse of the St. Francis Dam, Santa Clara River Valley, CA, 1928. Glass plate negative, Los Angeles Times Photographic Collection, UCLA Library Special Collections.

Large stepped piece of the St. Francis Dam on the canyon floor after its collapse. San Francisquito Canyon, CA, 1928. Glass plate negative, Los Angeles Times Photographic Collection, UCLA Library Special Collections.
Large stepped piece of the St. Francis Dam on the canyon floor after its collapse. San Francisquito Canyon, CA, 1928. Glass plate negative, Los Angeles Times Photographic Collection, UCLA Library Special Collections.
William Mulholland (pointing) and 4 other men on the east bank of the St. Francis Reservoir, San Francisquito Canyon, circa 1926-1928. Nitrate film, Los Angeles Times Photographic Collection, UCLA Library Special Collections.
William Mulholland (pointing) and 4 other men on the east bank of the St. Francis Reservoir, San Francisquito Canyon, circa 1926-1928. Nitrate film, Los Angeles Times Photographic Collection, UCLA Library Special Collections.

William Mulholland, a “self taught” engineer, had received much praise and admiration for his work in completing the Los Angeles-Owens River Aqueduct. As the chief engineer of the City of Los Angeles Bureau of Water Works and Supply, Mulholland continued to seek new water sources to fuel the burgeoning city’s growth.

Tactics for achieving this goal often relied on systematic dispossession of local residents via land grabs and the extraction of natural resources. These practices led to destructive environmental impacts, at the same time deepening socio-economic divides along lines of race and class.

After the collapse, practices of segregation and discrimination impacted recovery, relief efforts and payouts, favoring White residents of the area and neglecting affected migrant worker communities of Mexican and Japanese descent.

Mulholland accepted full responsibility for the disaster and stepped down from his role as chief engineer, but neither he nor the Bureau of Water Works and Supply were found criminally culpable.

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