St. Francis Dam Disaster in the US: Tragedy of Arrogance!

In the early morning of March 13, 1928, one of the greatest engineering disasters in American history occurred in California. The St. Francis Dam, a symbol of the engineering ambition and rapid development of the city of Los Angeles (USA), suddenly collapsed.

Journey of construction and disaster

More than 52 million tons of water rushed down the Santa Clara Valley overnight, wiping out homes, killing more than 400 people, and leaving behind terrible human and environmental consequences. This was not only a tragedy, but also a valuable lesson in responsibility and care in engineering projects.

The construction journey and the overlooked warning signs

St. Francis Dam. (Photo: Getty images).

As California lured easterners to Los Angeles in the early 1900s, the city exploded with a growing population and its drinking water supply dwindled. With an insatiable appetite for growth, city leaders commissioned William Mulholland, chief engineer and superintendent of the Los Angeles Water System, to build the Los Angeles Aqueduct, which opened in 1913 and diverted water from the Owens Valley across 230 miles of desert.

But even the water pipes could not save this thriving city, whose population had grown from just over 100,000 in 1900 to more than 1 million in the 1920s. A seven-year stretch of near-record low rainfall and the city's exponential growth had put water supplies at risk.

To keep Los Angeles from drying out, Mulholland built a storage system to store water. The most ambitious part of the project was the St. Francis Dam, built 75 kilometers northwest of downtown Los Angeles. When completed in May 1926, the concrete arch dam stood 64 meters high and could hold more than 12 billion gallons of water, enough to supply the entire city for a year. The dam became a symbol of Los Angeles' growth and a source of pride for Mulholland, who was hailed as the city's 'savior.' However, throughout its construction and operation, there were alarming warning signs that were ignored.

In March 1928, winter rains forced Mulholland to announce that all irrigation would be suspended for several days, a move that would save millions of dollars. The rains had brought the reservoir behind St. Francis Dam to its maximum capacity. During a routine inspection of the concrete barrier on the morning of March 12, 1928, dam superintendent Tony Harnischfeger became concerned when he noticed a large leak on the western edge, possibly indicating that foundation material was being washed out from beneath the dam.

When informed, Mulholland went to investigate and assumed that this was a normal phenomenon caused by nearby construction projects. With absolute confidence in his work, he left without taking any precautions.

'There was some leakage observed, but it was considered insignificant. However, it was a sign that the dam was having problems,' said William Deverell, professor of history and co-director of the Huntington-USC Institute for California and the West.

While Mulholland had every confidence in the dam's integrity, rancher Chester Smith grew increasingly skeptical. While out tending cattle that day, he noticed a large leak on the west side of the barrier, with water splashing over the top of the barrier. Downstream of the dam, Smith went to bed nervously, keeping the gate open in case he needed to escape quickly.

Horrible disaster in the dark night

At 11:57 p.m. on March 12, 1928, the St. Francis Dam suddenly collapsed. In the darkness, a column of water more than 42 meters high rushed down the San Francisquito Canyon at a speed of 29 kilometers per hour. This artificial tsunami swept away everything in its path: houses, roads, orchards, and railroad tracks.

The ground north of Los Angeles began to shake. Houses shook. Windows shook. A large section of the dam burst open. Massive amounts of water, at great pressure, began to pour through the gap. Just two and a half minutes before midnight, the hillside just east of the dam was completely flattened.

In a chain reaction, the dam's gap grew larger and larger, and the land to the west soon shared the same fate. In the dark, without any warning, the dam's staircase-shaped wall collapsed, creating a terrible flood.

People living near the mountain were the first to feel the unsettling shaking of the ground, and before they could do anything, the waves had already arrived.

By about 12:45 a.m. on March 13, 1928, the flood—what survivors later called a 'huge black wall' —had left the San Francisquito Canyon, moving rapidly westward toward the Santa Clara River Valley where 10,000 residents slept.

Awakened by the sound of barking dogs, Smith heard the rumble and ran to higher ground, shouting to warn his family. Those precious seconds saved his life, but hundreds of others were not so lucky.

Living half a mile downstream, Harnischfeger, his girlfriend and their 6-year-old son were likely the first victims, although their bodies were never found. The floods killed 65 employees and family members at a nearby power plant, 84 Southern California Edison workers sleeping in tents at a construction camp and dozens of Mexican migrants picking fruit in the area.

The giant wave crashed into the victims, stripping them of their clothes, leaving them bruised and torn. It took months to collect the bodies from the rubble and mud.

The raging floodwaters were not only deadly, they were also devastating to the environment . They carried debris, trees, and even human remains out to sea. Bodies washed ashore as far as San Diego, making identification and an accurate death toll extremely difficult. Official reports put the death toll at 400, but the actual number could be much higher.

Expensive lesson

What remains of the St. Francis Dam. (Photo: Getty images).

"This investigation has been a very painful thing for me to attend," Mr. Mulholland said sadly on the stand . He said he felt like he wanted to die like the victims so he wouldn't have to stand trial after the disaster. The chief engineer testified that he saw no signs that the dam would fail.

The inquiry cleared Mulholland, but the verdict stated that the construction and operation of a major dam should never be left to the discretion of a single person without the scrutiny of independent expert review, no matter how prominent that person.

A commission of engineers and geologists appointed by California Governor CC Young concluded that the conglomerate beneath the west abutment was not strong enough to support the massive structure, and water had seeped into the foundation of the St. Francis Dam, lifting it. Investigators found other design flaws , including raising the dam from its original proposed height of 180 feet to 210 feet without increasing the width of the base to accommodate the load, significantly reducing the structure's stability. At the same time, geological studies found that the east abutment even sat on the site of a landslide that had occurred and showed signs of further landslides, which Mulholland had not detected.

' The geological structure on both sides of the dam is different and that creates the potential for catastrophic failure,' said Professor Deverell . He concluded that because Mulholland was at the height of its reputation, power and authority, little attention was paid to the checks and balances to ensure the quality and safety of the dam.

The disaster destroyed Mulholland's reputation, forcing him to resign soon after. He spent the rest of his life in deep remorse, carrying the burden of a man who had witnessed the worst consequences of his mistake.

The St. Francis Dam disaster not only claimed hundreds of lives but also sent shockwaves through the civil engineering industry. Lessons learned from the event have radically changed safety standards for the design and operation of hydropower projects in the United States. Accordingly, large projects require the participation of many experts from different fields and close supervision from independent agencies. The design of large projects, especially hydropower dams, requires careful consideration of geological factors to avoid the risk of unstable foundations.

The disaster also highlighted the need for emergency response plans. At the time of the incident, warnings were not issued in time, leaving hundreds of people downstream without enough time to evacuate. Information and early warning systems in key facilities were subsequently improved to minimize casualties in the event of a similar disaster.

The incident also highlighted social and legal responsibilities. Many companies and local governments were criticized for their lack of oversight, leading to a series of new safety standards being issued. It also marked a turning point in forcing engineers and contractors to take more responsibility for ensuring the integrity of structures.

Tombstones commemorating the seven families who died in the disaster. (Photo: Gettyimages).

Today, all that remains of the St. Francis Dam are giant concrete fragments scattered across the San Francisquito Canyon. The site has become a historical memorial, a reminder of the disaster that occurred. In 2019, the area was designated the St. Francis National Monument and Memorial, in hopes of preserving the memory of the victims and the lessons learned from the tragedy.

Plans are still underway to build a tourist center, museum and memorials. A wall with the names of the victims is expected to be built to remember those who died in the disaster.

The St. Francis Dam disaster is not just a story of a giant structure collapsing, but also a symbol of ambition and mismanagement. It is a reminder that in any engineering project, care and responsibility must always be paramount. The lives lost cannot be recovered, but the lessons of this event will forever guide future generations of engineers.