Water and Power Associates Informing the Public about Critical Water and Energy Issues facing Los Angeles and California

Historical Notes

Construction of the St. Francis Dam began on March 9th, 1925. It was completed a year later, almost to the day. The colossal concrete structure was 205 feet high, 1225 feet long on its crest, 150 feet long at its base, and 160 feet thick at the stream level.

The St. Francis Dam failed catastrophically upon being filled for the first time, near midnight on March 12, 1928. Over 450 people perished as the flooding waters raced through the San Francisquito and Santa Clara River valleys and continued on its 54 mile course to the ocean. It ranks as one of worst American civil engineering failures in the 20th Century.

Historical Notes

It would take two years after its completion before the new lake behind it would be filled. The new reservoir would provide 38,000 acre-feet of storage from water flowing on the Los Angeles Aqueduct.

Historical Notes

The concrete-arched gravity dam was built by the City of Los Angeles Bureau of Water Works and Supply (now DWP) under the supervision of its chief engineer, William Mulholland.

Historical Notes

The St. Francis Dam was given an anglicized version of the name of the creek bed on which it rested (San Francisquito).

Historical Notes

On March 9th, 1925, preliminary work began in preparing for the construction on the 600-foot-long, 175-foot-high St. Francis Dam.

Historical Notes

The dam was designed to be 175 feet tall and to hold back a reservoir of 30,000 acre feet. However, immediately after construction began in 1925, Mulholland decided to raise the dam 10 feet and increase the capacity of the reservoir to 32,000 acre feet. Since little construction had been completed, some minor changes were made in the design to accommodate the change.*

Historical Notes

In July 1925, when the dam was about halfway completed, Mulholland again decided to raise the dam another 10 feet to a total height of 195 feet. A “wing dyke” had to be constructed on the western side of the dam to keep water from spilling over a low ridge when the reservoir filled.*

Historical Notes

Gravity dams like the St. Francis Dam use their weight to resist the water pressure exerted on them. The St. Francis Dam was increased in height from the designed 175 feet to 195 feet at completion, without any substantial widening of the dam’s base. Such changes would not occur with modern engineering practices, but little was said about the changes in 1925.*

Historical Notes

From left to right can be seen Fred Fischer, R. del Valle, ???, William Mulholland and John R. Haynes.

Historical Notes

The dam crumbled at 11:57 pm on March 12, 1928, scarcely 12 hours after Mulholland had inspected it. There were no surviving eyewitnesses to the failure, but one man on the road about a half-mile away from the dam recalls feeling a strange shaking of the ground and the sound of “crashing, falling blocks.” The shaking he felt was no earthquake but rather the tumble of incredibly heavy pieces of concrete that were falling off the dam.^*

(1928)* - A man in rubber boots stands atop a mound of rocks and mud formed as a result of the failure of the St. Francis Dam in 1928. The dam collapsed in March of 1928 at 11:57 p.m., sending 12 billion gallons of water rushing down the Santa Clara River Valley.

Historical Notes

The center section of the dam, later nicknamed "The Tombstone", remained standing; the rest broke into numerous smaller and several large pieces most of which were washed downstream. The largest, weighing 10,000 tons, was found about three-quarters of a mile down from the dam site.*^

Side view of a massive concrete slab nicknamed "The Tombstone". This is the center section, and the only remaining portion, of the St. Francis Dam after its disastrous collapse in March 1928. Several large concrete blocks can be seen scattered throughout the area, and a few people can be seen along the road at the base of the mountain as well as atop a remaining portion of the bridge in the far distance.

Historical Notes

A few months after the dam's collapse, 18-year-old Lercy Parker fell to his death from the standing section after his friend, in playing a joke, had thrown a dead rattlesnake at him.*^

Historical Notes

In May 1929, the upright section was toppled with dynamite and the remaining blocks were demolished with bulldozers and jackhammers to discourage sightseers and souvenir hunters from exploring the ruins.*^

Historical Notes

Just past the Ventura County line along the Santa Clara River was a railroad siding called Kemp. There, a group of 150 workers for the Edison company were fast asleep in a tent camp used while they were building a transmission line. Night watchman Ed Locke watched in horror as the huge flood of water approached the camp. He ran through the camp, waking up as many people as possible.

Locke, a true hero of the disaster, perished that night, along with 84 of the workers as the flood hit a geologic outcropping called Blue Cut, which created a whirlpool effect that uprooted the tents. Most of the survivors had their tents zipped up, which allowed them to float on the whirlpool.*^*

Historical Notes

There were other heroes to recognize at Santa Paula. Louise Gipe, a night telephone operator at Santa Paula, received a call from the Pacific Long Distance telephone operator at 1:30 a.m., warning of the flood headed her way. Ignoring the peril to her own life, she stayed at her post, notifying California Highway Patrolman Thornton Edwards and calling residents in the low-lying areas of Santa Paula to warn them about the impending flood.

Edwards would become known as the "Paul Revere of the St. Francis Flood" as he raced wildly from door to door warning residents of Santa Paula. While Edwards spread the alarm through Santa Paula, deputy sheriff Eddie Hearne raced up the Santa Clara River Valley toward the flood with his siren blaring to warn residents. He made it as far as Fillmore, where he met the flood waters and had to stop his wild ride.*^*

There's a monument to their deeds in downtown Santa Paula, a sculpture called "The Watchers" that depicts the two motorcycle policemen who rode through town spreading the word.

Historical Notes

The disaster was primarily caused by the ancient landslide material on which the eastern abutment of the dam was built, which would have been impossible for the geologists of the 1920s to detect. Two of the world's leading geologists at the time, John C. Branner of Stanford University and Carl E. Grunsky, had found no fault with the San Francisquito rock. Therefore, an inquest jury determined responsibility for the disaster lay with the governmental organizations which oversaw the dam's construction and the dam's designer and engineer, Mulholland, but cleared Mulholland of any charges, since neither he nor anyone else at the time could have known of the instability of the rock formations on which the dam was built. The hearings also recommended that "the construction and operation of a great dam should never be left to the sole judgment of one man, no matter how eminent."*^

Follow-Up Analysis

J. David Rogers, a professor of geological engineering at Missouri University of Science and Technology, published a comprehensive account of the dam's failure. The dam's failure can be attributed to three major factors: the instability of the ancient landslide material on which the dam was built, the failure to compensate for the additional height added to the dam's design, and the design and construction being overseen by only one person.*^

Aftermath

Despite some reports absolving Mulholland of culpability, the collapse ushered in a public distrust of all prior Mulholland projects. The aqueduct was re-evaluated, reservoirs double-checked, and his prior dams were re-enforced with more earth. The famed Mulholland Dam in Hollywood, which was similar in design to the St. Francis Dam, was also evaluated and re-enforced.**^

Click HERE to see more in Early Views of the Mulholland Dam and Hollywood Reservoir.

(1928)#* - View showing William Mulholland testifying on the witness stand on March 26, 1928 in Los Angeles, at the coroner's inquest.

Aftermath

Mulholland took responsibility in a way that no public figure would today. During the official inquest, he claimed the mistake as entirely his own. “The only ones I envy about this thing are the ones who are dead,” the crestfallen chief announced.

He retired from the Bureau of Water Works and Supply in March 1929. His assistant, Harvey Van Norman, succeeded him as Chief Engineer and General Manager. Mulholland was retained as Chief Consulting Engineer for a while, however, in later years, he retreated into a life of semi-isolation. He died in 1935, at the age of 79.*^

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