The St. Francis Dam was built between 1924 and 1926 under the supervision of William Mulholland, then-chief engineer and general manager of the Bureau of Water Works and Supply (now known as Los Angeles Department of Water and Power); it was a concrete gravity-arch dam designed to create a reservoir as part of the Los Angeles Aqueduct. During construction of the dam, Mulholland decided to make changes in the original design, eventually raising the height of the dam from 175 feet to 195 feet, which in turn increased the capacity of the reservoir from 30,000 to more than 38,000 acre-feet of water. On March 7, 1928, the reservoir was filled to capacity for the first time. Several cracks had been noticed prior to filling, and more cracks and leaks appeared after it was full. Three minutes before midnight on March 12, 1928, the dam catastrophically failed and 12 billion gallons of water surged down San Francisquito Canyon in a flood wave, taking victims and destroying everything in its path. The official death toll in August 1928 was 385, but the bodies continued to be discovered every few years - the actual body count is speculated to be more than 600 victims. William Mulholland was determined to be partially responsible for the disaster (along with governmental organizations which oversaw the dam's construction), but cleared of any charges since he could not have known of the instability of the rock formations on which the dam was built. Mulholland retired from the LADWP soon after the disaster and retreated into a life of self-imposed isolation. He died in 1935 at the age of 79. View of a massive concrete slab nicknamed "The Tombstone." This is the center section - the only remaining portion - of the St. Francis Dam after its disastrous collapse in March 1928. The St. Francis Dam was located 40 miles northwest of Los Angeles, in the San Francisquito Canyon near the city of Santa Clarita.
Concrete dams--California--Los Angeles County Dam failures--California--Los Angeles County Reservoirs--California--Los Angeles County Disasters--California--Los Angeles County Canyons--California--Los Angeles County Lost architecture--California--Los Angeles County Mulholland, William,1855-1935 Saint Francis Dam (Calif.) San Francisquito Canyon (Calif.) Los Angeles (Calif.).Bureau of Water Works & Supply
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