Floodpath
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In less than five minutes, the pileup of debris from the eastern hillside pushes blocks 5 and 7 across the dam’s downstream face, shearing off some of the stair steps on block 1 (the Tombstone). In the process, block 5 is rotated upward toward the west. At the same time, water crossing from the west through the gap on the east abutment causes the stilling well of the Stevens Gauge to bend and break. As this happens, with a huge shift the western portion of the structure tilts and rotates eastward.
Saturated schist escapes in a turbid flow.
Further landslide debris creates temporary barriers to the flood.
In only a matter of minutes, after the reservoir has fallen seventy to eighty feet, as later indicated by the scour line on the west abutment, the red conglomerate on that side of the dam begins to crumble.
As tons of water escape, blocks 11 and 16 are flushed downstream, leaving a gap beneath the wing dike. The remainder of the west portion of the dam below the wing dike snaps off and is carried away. The flood surge gouges a thirty-five-foot hole in the canyon floor slightly downstream. As this happens, what’s left of the dam rocks backward, tilting 54 degrees while huge fragments continue to tumble downstream in a viscous floodsurge.
The west abutment collapses.
Block 1 (the Tombstone) rocks and twists; remaining blocks fall against east abutment.
With the failure nearing completion, floodwaters push past either side and encircle the Tombstone, which is now all that remains standing. With the reservoir rapidly emptying, as a grim coda small rocks and loose soil from the east-side landslide continue to fall, settling on top of blocks 5 and 7.
In his computer-informed scenario Rogers agrees with earlier investigators that the collapse of both sides of the St. Francis Dam were only minutes apart. In less than an hour, the entire 12.4 billion gallons in the largest lake in Southern California was flooding San Francisquito Canyon and rumbling toward the Santa Clara River Valley. The collapse was over, but the downstream horrors had barely begun.
Future investigations and new analytical tools may add more detail to this scenario, and perhaps create a new version of the failure of the St. Francis Dam, but for now this is probably as close as we can get to reliving the first terrifying moments of twentieth-century America’s deadliest man-made disaster.
16.
After the Fall
In the twenty-first century world of computer-assisted engineering, William Mulholland, if he is remembered at all, is commonly denigrated as an arrogant and ill-informed relic from a less enlightened era. He placed the St. Francis Dam in a poor location and didn’t include enough safety features in his design, although they probably wouldn’t have made a difference given the surrounding geology. It’s popularly assumed engineers today know better and would never repeat such disastrous miscalculations.
During decades of research I learned that major tragedies like the failure of the St. Francis Dam are indeed rare, but as long as there are dams there will be dam disasters. This is true not because large dams are inherently dangerous, but because of the sometimes overwhelming vagaries of nature and the limitations of the humans who build them, no matter how educated and well-meaning they may be. Also, as exposed by the catastrophe in San Francisquito Canyon, social, political, and economic priorities can play a role, adding destabilizing pressures of limited time and tight budgets, beyond the weight of water in a reservoir.
A prominent engineering historian remarked, “Safety is foreseeing failure.”1 A reminder that modern dams are far from invulnerable occurred shortly after nine P.M. on December 2, 1959, when the concrete arch Malpasset Dam, near the French Riviera, was breached. The ensuing flood took 421 lives. An investigation revealed that insufficient funding had resulted in an inadequate study of the geology underlying the dam, including a proper evaluation of a dormant earthquake fault, which formed a plane of weakness beneath the structure. Heavy rain had brought the reservoir within inches of capacity, but managers, concerned about the release of excess water downstream, which could cause flooding, refused to open relief valves. Uplift also was at work as water accumulated beneath the dam’s foundation. In many ways, the Malpasset failure was a sad replay of what happened in San Francisquito Canyon thirty-one years before.
The Vajont Dam, sixty-eight miles north of Venice, Italy, was built by a private Italian utility company in the late 1950s. Rising 860 feet, at the time it was the highest dam in the world. The concrete arch barrier, part of an ambitious hydroelectric project, was overtopped on October 9, 1963. An entire mountainside (approximately 972 million cubic yards) suddenly fell into the reservoir, lifting the water and adding overwhelming weight behind the dam (more memories of the St. Francis failure). The loss of life was horrifying: an estimated 2,600 people.
Closer to Los Angeles, the Baldwin Hills Reservoir failed on December 14, 1963. The storage facility had been built by a DWP team that included Ralph R. Proctor, who worked on the St. Francis Dam. Proctor, a seasoned and respected engineer, had been a valuable expert witness at the Los Angeles Coroner’s Inquest in 1928. The embankment dam in the Baldwin Hills, southwest of downtown Los Angeles, was breached with enough time for downstream warnings and extensive aerial coverage on local television. Thousands watched live, including Toni Harnischfeger and Betty Edwards. Unlike the DWP’s earlier dam failure in San Francisquito Canyon, fortunately only five people lost their lives in the flood. The legacy of extensive oil drilling in the area, a major component of the Los Angeles economy in the 1920s, was one explanation why the Baldwin Hills foundation failed.
Virtually every investigator who criticized the design or construction techniques Mulholland used to build the St. Francis Dam cited examples of Bureau of Reclamation projects as models of 1920s best practices. At 7:30 A.M. on June 5, 1976, the 305-foot-high earthen Teton Dam in Idaho became an embarrassing modern exception. As the reservoir was filled for the first time, the crest of the structure sagged and collapsed. After the failure, forensic engineers reported that the geology of the site was porous volcanic rock, including tufa, the material Mulholland was criticized for using in the Owens River Aqueduct. Eleven people died, and property losses were calculated at $1 billion.
By the late 1970s, with changing national priorities and almost every major American river interrupted with dams, the era of great dam construction in America came to a halt. But other countries were only beginning. Just as multiuse dams, aqueducts, and ambitious power-generation projects had transformed the United States, large-scale plans in Latin America, India, and the People’s Republic of China are attempting to hasten the future with dam technology, including ambitious flood control, water storage, and hydroelectric plants. The successes are often unprecedented, but so are the failures.
On August 11, 1979, the earthen embankment Machhu II Dam in India was a victim of heavy rains and flooding. The reservoir was hit by a torrent three times greater than the structure’s spillway capacity. Given the size of the local population, determining an accurate death count was difficult. Some put the number as high as twenty-five thousand.
The failure of Macchu II was disastrous, but four years before, on August 8, 1975, after a series of tropical storms, a chain reaction of dam failures occurred in China’s Hunan Province, resulting in a death toll between 171,000 and 230,000 people. Eleven million survivors lost their homes.
With the help of advisors from the Soviet Union, work had begun on the earthen Banqiao Dam in 1951. After early construction errors were corrected, using what was considered the latest technology at the time, the 381-foot-high barrier was dubbed “the iron dam” and declared indestructible. When the unbreakable iron dam broke apart, it released a six-mile-wide flood that traveled thirty-four miles, taking out another sixty-one smaller barriers along the way.2
Eventually, the Banqiao Dam was rebuilt and the Chinese government continued its monumental hydroelectric and irrigation program, including the largest and most powerful dam in the world, the Three Gorges project, which opened in 2008
. The Three Gorges Dam is an attempt to control the Yangtze River, which flows 3,964 miles, the longest waterway in the world. The barrier, located between the cities of Wuhan and Chongqing, stands as an impressive accomplishment in the history of engineering, with transformative regional benefits, but dam builders in China and around the world are keeping a close watch on the buildup of silt, and they regularly measure stresses to anticipate weaknesses in the massive structure. The losses from a breach at Three Gorges would be almost unimaginable.
Since the catastrophe in San Francisquito Canyon, all the deadliest dam disasters have occurred outside the United States, but dams continue to collapse in America. Most are smaller structures, causing few if any casualties, but between 2005 and 2013, the Association of State Dam Safety Officials reported more than 170 dam and levee failures and nearly 600 “incidents” as old dams aged and maintenance and safety measures were ignored or postponed.3 The great tragedy caused by Hurricane Katrina in 2005 overshadowed them all.
Sixty-five percent of U.S. dams are privately owned, and lack of effective maintenance programs and inadequate financial resources can impede safety efforts. Of the dams under government regulation, 80 percent are the responsibility of states, not federal authorities. In a 2013 count, Texas had the most dams, with seven thousand; Delaware had the fewest, with eighty-six. At both state and federal levels, tax allocations for dam maintenance and repairs were often insufficient.
As part of the legacy of the St. Francis Dam disaster, California has the most extensive dam-safety program in the United States, overseeing one of the largest and most important water systems in the world, much of which is the legacy of William Mulholland. Even so, concerns remained in the second decade of the twenty-first century as the American Southwest faced one of the worst droughts in the region’s history—a natural challenge that, given the importance of California to the American economy, had national and international consequences. As a result, the debate over the fate of dams and water-allocation priorities became more critical than ever.
Also, increasingly, Los Angeles received reminders that hundreds of miles of the city’s underground water infrastructure date to the annexation fever after the completion of the Owens River Aqueduct. Since then, growth continued to surge and politicians and voters were hesitant to pay the price for infrastructure maintenance and repair. As only one example, in 2014 a thirty-inch pipe burst beneath Sunset Boulevard, near the upscale Los Angeles neighborhood of Bel Air. Twenty million gallons of water flooded a portion of the UCLA campus. The cost of cleanup and repairs ran into the multimillions.4 Such water-main breaks are not uncommon across the United States, especially in cities such as Boston, New York, Philadelphia, and Washington, D.C., where pipes are often older than in Los Angeles.
The consequences of a major broken water main can be destructive and costly, but nothing compared to the failure of a dam, even a relatively small one. Although most major dam failures occur within a relatively short time after construction (two years old, the St. Francis was somewhat of an exception), even well-built dams have life-spans. With age comes added concerns for safety. In 2015 the average age of a U.S. dam was more than fifty years, a long time to hold back tons of water. To respond to this, timely and effective maintenance programs are considered vital. But to some, even these aren’t enough.
Beginning in the 1990s, a movement to remove many old or outdated dams, rather than construct new ones, gained credence. Environmental activists cited economic and safety reasons to argue that aged barriers need to be laid to rest, allowing fish to swim free and the surrounding environment to return to a natural state.
In 2004, the 1910 Embry Dam on the Rappahannock River in Virginia was demolished by the U.S. Army Corps of Engineers. In the Olympic Peninsula of Washington State, the 210-foot-high concrete arch Elwah Dam, built for hydroelectric power in 1927, was blasted by dynamite in 2011, the first stage of a multiyear demolition schedule. Representatives from the U.S. Department of the Interior came to watch and acknowledge their support.
Closer to the Santa Clara River Valley, in 2011 the decaying 1948 Matilija Dam, in the mountains near the Ventura County community of Ojai, was slated for removal. In an act of surreptitious mischief to call attention to the situation and hasten the day, in the middle of the night anti-dam protestors scaled the barrier and painted a huge pair of scissors and a dotted line down the old dam’s downstream face.5
Perhaps the most controversial dam on the environmental hit list was Glen Canyon, completed in 1966 on the Colorado River, near the Utah-Arizona border. The 710-foot-high barrier creates Lake Powell, a popular recreation site. The lake also serves to catch sediment accumulating in Lake Mead, behind the Hoover Dam. In response to boating enthusiasts and others, environmentalists argued that a substantial amount of water stored in Lake Powell was lost to evaporation, and over the years the habitat of smaller fish, native to Colorado River tributaries, had been endangered.
Faced with environmentalist calls to tear down old or outmoded dams as well as perfectly sound structures like Glen Canyon, advocates of expanded water and power infrastructure argue that the tens of millions of dollars needed to raze old barriers would be better spent repairing and enhancing deteriorating water and hydropower systems, or even building more, especially in the midst of ongoing threats of drought. The great era of American dam building may have been over, but a modern debate about dams and reservoirs was more timely than ever. Connected to this is the debate over large-scale clean energy—hydroelectric sources versus fossil fuels, nuclear, and even solar and wind.
One thing is certain—the twenty-first-century anti-dam movement would have confused and infuriated William Mulholland. The Chief was a nineteenth-century man empowered by twentieth-century technology. In his day, men like him were viewed as heroes of human ingenuity, harnessing nature as a source of power and raw materials to build things, improve life in a man-made world, and realize the Progressive/Utilitarian ideal of “the greatest good for the greatest number.”
In pursuit of that assumed progress, Mulholland employed technology to dramatically alter natural ecosystems—a word not yet in the early 1900s vocabulary. As a result of the Chief’s greatest engineering achievement, the Owens River Aqueduct, modern Los Angeles was born, changing the American West and the history of the United States. But in the process, much of the Owens Valley was sucked dry. For decades, dust storms plagued the area, with drastic impact of wildlife and public health.6
As L.A.’s population continued to soar, in less than fifty years, Mulholland’s 1913 Aqueduct was unable to fully supply the city’s legal liquid allotment. Los Angeles reached father north into Mono County, and in 1970 a second aqueduct was completed, beginning at Haiwee Reservoir, south of Owens Lake, paralleling the old pipeline south, and in the process reigniting California’s decades-old Little Civil War.
On September 15, 1976, after the DWP increased underground pumping in the Owens Valley, dynamiters—allegedly residents of Inyo County—expressed their anger again by blasting another hole in L.A.’s Aqueduct, temporarily halting the flow. The next day, someone with a “very heavy” longbow sent an arrow bearing a stick of dynamite arching toward the William Mulholland Memorial Fountain, but the explosive landed in the decorative pool and failed to detonate.7
Despite continued hostilities and decades of noirish recriminations, like much of history, Bill Mulholland’s legacy is less clear-cut than polemics allow. Certainly, the failure of the St. Francis Dam marked the beginning of the end for the last vestiges of an unfettered nineteenth-century attitude toward engineering and nature, but the consequences are more complex.
In the Owens Valley much damage was done, but, as the Valley’s principal landlord, the Department of Water and Power also encouraged ranching and tourism, limiting the rampant real estate development that overran other once-rural areas including, ironically, the San Fernando Valley. In 2007 a revisionist economist argued that the DWP’s land-use policies increased property va
lues in the area, and by encouraging travel and recreational uses, Los Angeles preserved undeveloped land and sustained a more reliable local economy, especially compared to the limited farming and ranching of 1905.8 Beyond this, it was argued that even if Mulholland’s first aqueduct had never been built, just ongoing diversion by Owens Valley farmers and ranchers would eventually have left shallow and alkaline Owens Lake perhaps just as dry and dusty.
With the beginning of the twenty-first century, against the odds and after more than a century of lawsuits and dynamite, California’s Little Civil War showed signs of ending—perhaps this time for real. After a series of defeats in the courts, in December 2006 the DWP began to divert a portion of Aqueduct water back into the Owens River, and the city launched an expansive anti-dust program that included various eco-friendly measures such as partially refilling Owens Lake and stabilizing vegetation in the areas around it. For years, this remediation siphoned a sizable portion of the DWP’s annual budget. Finally, in 2014 a landmark agreement was reached, instituting innovative new methods to mitigate dust in the Owens Valley, conserve water resources, and save money in the process. It was a negotiated settlement between competing interests that included the city, Valley cattle ranchers, and environmentalists—a microcosm of a debate over the future that is taking place on a national and even international level.
In May 2015, as a dramatic example of this agreement and the impact of a record California drought, for the first time since 1913, DWP blocked flow from the Owens River Aqueduct to meet obligations to Owens Valley residents and preserve dwindling water resources in the north. Much of the loss was absorbed by reservoirs in the south, closer to Los Angeles, benefiting from William Mulholland’s water storage strategy during the 1920s. Although the Chief’s rush to build new dams and reservoirs nearly ninety years ago was marred by the devastating failure of the St. Francis Dam, ironically the results of his urgent efforts were a lifesaver, at least temporarily, for early twenty-first-century L.A.’s drought-driven water needs.