Prevention is Dam Important
As we approach mid-March, we will again discuss one of the worst disasters in California history that occurred in the Santa Clarita Valley: the collapse of the St. Francis Dam in northern Los Angeles County on March 12, 1928. Over 450 people drowned due to insufficient warnings about the torrential floodwaters heading toward the ocean, but times have changed. We should take advantage of new technology.
The Santa Clarita Valley comprises many canyons, and up San Francisquito Canyon was perched the St. Francis Dam. Built from 1924 to 1926, it augmented the water supply due to Los Angeles’s burgeoning growth. However, engineering faults in the dam’s construction led to its fateful collapse.
The next valley over now sits the Castaic Dam, which holds 8.5 times more water than the St. Francis Dam. The surrounding area has grown immensely, with the City of Santa Clarita pushing their borders toward the dam’s base. Plus, homes and businesses have brought thousands of people to work, shop, and attend schools nearby.
The dam is located 17 miles north of the freeway interchange known for the infamous 1994 earthquake photos that depicted mangled and broken highway ramps. Just around the corner is Sylmar, where the VA hospital collapsed during the 1971 earthquake.
The Castaic Dam is supposed to withstand an 8.0-magnitude earthquake. Two new faults have recently been detected nearby, so how do we know the dam won’t fail? Should there be a rupture, a flood of water will similarly follow that of the St. Francis Dam flow. Have we learned any lessons?
Therefore, what has Los Angeles County, the City of Santa Clarita, and downstream towns done to warn and prevent residents and businesses from another disaster?
Here are a few recommendations:
- Have geologic studies calculate the depth, height, speed, and direction of water flow to the ocean in the event of a dam rupture;
- Determine what structures might be in great danger;
- Practice evacuation drills in schools;
- Find highest ground escape routes so people can move upward;
- Figure out ways to get cars off the road, especially since the Interstate 5 and State Highway 126 intersection is directly in the line of flood flow;
- Have warning signs be activated especially on these roads, and make sure there can be immediate cell phone communication of a pending flood even in an earthquake;
- Establish a local group to develop and implement these life-saving preventive measures immediately, and seek information on how other communities in similar situations prepare themselves for this potential emergency.
As a physician, prevention has always been the most worthy way to care for my patients.
Over 450 people were lost 97 years ago, but if it has taken this long to learn important lessons, I’m good with that.
Gene Dorio, M.D.
Originally published in The Signal, our local newspaper, on March 5, 2025
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