Located in the northwest curved corner of the San Fernando Valley, the Chatsworth Reservoir was built on an alluvial plain, a natural drainage for the creeks, some named after canyons, that seasonally run out of the rocky ridges and flow down the chaparral ravines and canyons of the Santa Susana Mountains. The Bureau of Water Works and Supply, as the Department of Water and Power was called at the time, developed the reservoir as the last link in a series of nineteen water retention basins meant to store water from the aqueduct system that carried water down from the Owens Valley. It was an earth-filled dam (also called an earthen dam or terrain dam) made of compacted earth.
One hundred years ago, April 9, 1918 William Mullholland, visionary, chief engineer and general manager of the Water Department, turned on the spigot to fill the reservoir.
Ten years later, March 12, 1928 Mullholland, a self-taught engineer, traveled about ten miles above what is now the city of Santa Clarita to inspect another dam in the San Francisquito Canyon of the Sierra Peloma Mountains. The St. Francis Dam was a curved concrete gravity dam, completed two years earlier in 1926. Leaking cracks had been observed. These fissures were dismissed as typical conditions for this type of structure. The leaks had existed for a considerable period of time before William Mullholland made his last inspection. He declared the structure sound and safe.
Three minutes before midnight, twelve hours after the inspection, the dam failed and let loose a tremendous flood that destroyed ranches and homes all the way to Ventura. It was estimated that 431 lives were washed away that night, drowned, lost deep in the mud and debris.
That was the end of Mullholland’s career. His reputation suffered for a while. However, the city did keep the drive and highway named, in 1924, after the man that brought water to the Valley. He died at the age of 79, seven years after the flood.
The St. Francis Flood is the second worse loss of life in California history, after the San Francisco earthquake and fire of 1906.
From 1920 to 1950 the Chatsworth Reservoir provided water mostly to the ranches and orange groves that made up the west end of the Valley. When housing tracts started moving in, the quality of water needed to meet higher standards. The reservoir was drained and improvements began in 1969. On February 10, 1971 the Sylmar earthquake woke the residents of the San Fernando Valley. Freeways collapsed and hospitals were in ruins, thirty-nine people missing in one pile of rubble. Dams became a concern. In Granada Hills neighborhoods were evacuated below the Van Norman Reservoirs. A family of four stayed at our house in Burbank until the evacuation order was lifted. The earth filled dam did not inspire confidence after the quake. In 1972 it was officially taken out of service. And so, it has remained. The reservoir was once the end of the Owens River and the beginning of the Los Angeles River.
part three in a series