Cause of St. Francis Dam collapse more concrete than initially verified

June 12, 2009
Second in a series of articles exploring the St. Francis Dam Disaster
Santa Paula News

Forefront and officially, it was declared that a pesky mountain shoulder anchoring one wing of the St. Francis Dam had caused the second largest disaster in California history.

By Peggy KellySanta Paula TimesForefront and officially, it was declared that a pesky mountain shoulder anchoring one wing of the St. Francis Dam had caused the second largest disaster in California history. After all, you can’t argue with Mother Nature, who casually shrugged that shoulder, causing the landslide, centuries in the making but waiting for the perfect moment, to arrive at 11:57:30 p.m. on March 12, 1928.For decades - including a 1990’s reaffirmation - the official reason the “build-it-quick-and-quietly” dam collapsed was the geology of remote San Francisquito Canyon. So as not to tarnish the reputation of the great engineer William Mulholland, the inherently poor design and additions to water capacity unsupported by basic engineering principals were glossed over. But mention was strongly made that a lack of project oversight by the Los Angeles water agency - or anybody else for that matter - must never be replicated.The building of the St. Francis Dam began without fanfare; no golden shovel groundbreaking, flowery political speeches, or heartfelt beseeching of a higher power to smile on the City of Angels. Rather, construction started with concealment more akin to hastily burying a murder victim.Ventura County only learned that an L.A. County dam was going up east of the Santa Clara River Valley once the pour of hundreds of thousands of tons of concrete was already in progress. Area ranchers feared losing their water to L.A. just as their hapless Owens Valley counterparts, whose vital supply became the source of the California Aqueduct.When completed by Mulholland in 1913 the aqueduct led to the creation of the San Fernando Valley, a slight shifting of priorities cited for the successful bond drive approved by oblivious L.A. voters. Aqueduct sabotage by Owens Valley ranchers began in earnest in 1924 when their lake started to resemble a dust bowl. A manufactured drought was also highly reported, adding urgency to the construction of a new storage facility.Once they found out, outrage was heard from Santa Clara River Valley ranchers and lawsuits were hastily filed. But all in all, they couldn’t slow the scurry to store a year’s worth of Los Angeles-bound water needed in case of aqueduct interruption.Rumors almost outpaced River Valley agricultural production during dam construction, and some talk centered on the viability of the concrete itself. Nevertheless, after the disaster such suspicions were quickly squashed by the numerous reports and hearings dissecting the tragedy, accomplished - as with dam construction - at breakneck speed.But over the years the possibility the concrete itself failed perhaps crossed the minds of those holding the crumbly, pockmarked remnants of the disaster in their own hands.Tom McMullen had never held a piece of the tragedy, actually had never heard of the St. Francis Dam Disaster, not uncommon for those living outside - and even inside - the Golden State. It was only when McMullen was working on his University of Maryland thesis, which examined the construction of Hoover Dam, that he stumbled across references to the disaster, which he found had occurred within days of the official declaration that the St. Francis Dam was filled.McMullen had no idea of the tragedy, no handy reference to the destruction of the Santa Clara River Valley as 12 billion-plus gallons of water stored about 1,800 feet above sea level burst forth into the narrow San Francisquito Canyon. McMullen wasn’t alone: very few knew then - or know now - about the St. Francis Dam Disaster.The frantic waters, calming only when flooding over a wider river valley nestled between two watchful mountain ranges, was somehow lost to history. Newspapers did not report that tons of debris - the bodies of as many as 1,000 men, women and children, cars, animals, trees, railroad tracks, houses, barns, earth, bridges, whatever in its path - had also helped brake the deadly march of dam waters.At 3:05 a.m. when the waters reached Santa Paula, their initial 18 mph speed had slowed to 11.2 mph, a much lazier trip now that much of the River Valley consumed in that flood’s wake was part of its being. Finally, at 5:25 a.m., the flood and all it held - traveling at a leisurely 5.9 mph - spilled into the Pacific Ocean.The St. Francis Dam Disaster’s 54-mile trip was over, although the watery journey of some flood victims continued until they washed ashore on beaches as far south as Baja, California. The initial hue and cry was finally stilled - after all, the regions largest newspaper had ties to the growth that water made possible - and as the decades passed fewer and fewer Americans had an inkling of the tragedy.
McMullen had an avid interest in the construction of the Hoover Dam, the subject of his planned Master of Science thesis. Although undoubtedly running a weak second in McMullen’s initial thoughts, by the time he finished the paper the disaster got top billing.“The Saint Francis Dam Collapse and Its Impact on the Construction of the Hoover Dam” was submitted in 2004, but a it wasn’t until a few days before this year’s 81st anniversary of the disaster that McMullen was finally asked about it.“I was doing my civil engineering masters and was reading up on dams. A great story the Hoover Dam construction,” said McMullen in a March telephone interview. McMullen, now director of the University of Maryland’s College of Computer, Math and Physical Science, said when he initially saw references to the St. Francis, “It piqued my interest. I found it very interesting, from a project management” point of view.But the more he studied the disaster, the more McMullen found himself “surprised at the number of things” that firmly pointed away from the widely accepted “soft-shoulder-did-it” theory. He was, likewise, nagged by inexplicable construction issues.Of particular interest to McMullen was the shoddy official state report on the St. Francis Dam collapse, housed in the archives of the University of New Mexico. Governor C. C. Young had ordered the report compiled by four engineers and two geologists from California, a team headed by engineer A. J. Wiley of Boise, Idaho.The governor’s instructions to the Commission started with a statement emphasizing the importance of stored water to the state’s growth and pointing out that dams holding California’s future must be made safe for the people living below them. “All this,” instructed the governor, “is both elemental and fundamental.”McMullen found that after their first meeting on March 19, seven days following the collapse, the Commission completed the report in five days, before the disaster was even two weeks old. Accompanying the 13 pages of engineering team-written material were two pages each of Governor Young’s letters and rock and concrete tests, as well as 31 pictures and maps of visual filler.Not surprisingly to McMullen, the report concluded the failure was due to defective foundations and there was nothing to indicate the accepted theory of concrete gravity dam design was in error when built upon even ordinary bedrock. Most importantly to McMullen, the report noted that water storage - so vital a California resource - must and would hereafter be subject to the police powers of the state.“That the conclusion of the Report of the Commission mirrored the tone” of the governor’s instructions “did not surprise me,” McMullen wrote, however the author did find many important details in the report were found that “didn’t seem to be factored” or even acknowledged “into the conclusions.” Details such as the “unimportant” leaks through the main structure and wing wall, a discrepancy in foundation depths, the lack of an entire dam drainage system to relieve uplift pressure and the lack of grouting were glossed over.The concrete itself, noted McMullen, was “immediately excluded from having played a part in the disaster.” Geology of the dam site was what most concerned the Commission, who used almost 40 percent of their report to focus on the canyon walls and streambed.The Commission concluded defective foundations were what brought the St. Francis Dam down, and before the year was up Commission leader A.J. Wiley applied for Mulholland’s vacated leadership of the city’s water agency. About 75 more years elapsed before McMullen zeroed in on the inferior concrete coupled with shoddy construction as the reason that “eventually caused in my opinion the failure.”If the concrete itself had been a “of a better quality,” McMullen believes the dam “would not have fallen apart as it did.... It was so filled with fractures,” the 175,000 cubic yards of concrete just broke apart under the pressure of the waters that snaked through the fissures and swirled around varied sizes and shapes of dredged stream rock, delicately suspended in worrisome air pockets.The lack of proper curing and the quality of the pour work itself was a recipe for disaster, or rather the “catastrophic failure” that McMullen said those in charge must have at least suspected before the St. Francis Dam - a tragedy waiting in the dam wings above the Santa Clara River Valley - was only about 60 percent filled. And McMullen set out to prove the cause of the St. Francis Dam collapse was more concrete than initially verified, metaphorically as well as literally.

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