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“Documentation of the destruction of the St Francis Dam.” Newsreel combines a simulation of the dam breaking with footage of the actual aftermath. Silent.
Public domain film from the Prelinger Archive, slightly cropped to remove uneven edges, with the aspect ratio corrected, and mild video noise reduction applied.
The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).
The St. Francis Dam was a curved concrete gravity dam, built to create a large regulating and storage reservoir as part of the Los Angeles Aqueduct. It was located in San Francisquito Canyon, about 40 miles (64 km) northwest of Los Angeles, California, approximately 10 miles (16 km) north of Santa Clarita. The name “St. Francis” is an anglicized version of the name of the canyon.
The dam was designed and built between 1924 and 1926 by the Los Angeles Department of Water and Power, then named the Bureau of Water Works and Supply. The department was under the supervision of its General Manager and Chief Engineer, William Mulholland.
At two and a half minutes before midnight on March 12, 1928 the dam failed catastrophically and the resulting flood killed up to 600 people. The collapse of the St. Francis Dam is considered to be one of the worst American civil engineering failures of the 20th century and remains the second-greatest loss of life in California’s history, after the 1906 San Francisco Earthquake and fire. The disaster marked the end of Mulholland’s career…
Planning and design
In the early days of Los Angeles, the city’s water supply was obtained from the Los Angeles River. Water was brought from the river by a series of ditches called zanjas. A private water company, the Los Angeles City Water Company, leased the city’s waterworks and provided water to the city. Hired in 1878, as a zanjero (ditch tender) Mulholland proved to be a brilliant employee who after doing his day’s work would study textbooks on mathematics, hydraulics, geology and taught himself engineering and geology. Mulholland quickly moved up the ranks of the Water Company and was promoted to Superintendent in 1886.
In 1902, the City of Los Angeles took over the city’s water supply…
Mulholland supervised the design and construction of the Los Angeles Aqueduct, which at the time was the longest aqueduct in the world and uses gravity alone to bring the water 233 miles (380 km) from the Owens Valley to Los Angeles. The project was completed in 1913, on time and under budget, despite several setbacks. Excluding incidents of sabotage by Owens Valley residents in the early years, the aqueduct has operated well throughout its history and is still in operation…
The St. Francis would be only the second concrete dam to be designed and built by the Bureau of Water Works and Supply. The first was the near identical, in size and shape, Mulholland Dam…
Two and a half minutes before midnight on March 12, 1928, the St. Francis Dam catastrophically failed.
Although there were no eyewitnesses to the collapse, the time of 11:57:30 p.m. is the accepted time of the failure. This is due to the known facts that at this time, personnel of the Bureau of Water Works and Supply at both Receiving Stations in Los Angeles and at Powerhouse No. 1 noted a sharp drop in the voltage on their lines. At the same time a transformer at Southern California Edison’s Saugus substation exploded. That transformer was connected to their Lancaster power line… this line was severed as the eastern hillside and abutment gave way. The grounded lines caused a short, which in turn caused the transformer to explode…
As the dam collapsed, the reservoir’s 12.4 billion U.S. gallons (47 billion liters) of water began to surge down San Francisquito Canyon. The dam keeper and his family were most likely among the first casualties caught in the flood wave, which was at about 140 ft (43 m) high when it hit their cottage…
The flood devastated much of the towns of Fillmore, Santa Paula and Bardsdale before emptying its victims and debris into the Pacific Ocean near Ventura at Montalvo at 5:30 AM. The flood had taken only 5 hours and 27 minutes to travel the 54 miles (87 km) from the reservoir and dam site. At this time, it was almost two miles (3 km) wide and traveling at a speed of 6 mph (9.7 km/h). Bodies of victims were recovered from the Pacific Ocean, some as far south as the Mexican border, while others were never found…
The governor’s commission… “The foundation under the entire dam left very much to be desired… The west end was founded upon a reddish conglomerate which, even when dry, was of decidedly inferior strength and which, when wet, became so soft that most of it lost almost all rock characteristics…”
