June 2002

10 Technology Disasters

Continued from page 6

By Eric Scigliano

The St. Francis Dam burst

It's never wise to underestimate the forces of nature. William Mulholland, creator of the Los Angeles water system and a designer of the Hoover Dam and Panama Canal, met his Waterloo at the little-remembered St. Francis Dam in San Francisquito Canyon, 72 kilometers northwest of L.A. On March 12, 1928, one day after Mulholland examined it and declared it sound, the dam burst, sending a wall of water, reported as 24 meters high, hurtling toward the Pacific. More than 500 people in its path perished. An inquest blamed unstable rock formations for the collapse, but later investigation suggests that the dam's base was thinner than believed, and its engineers did not fully understand uplift forces or build in seepage relief. The underlying failure was more universal: the United States saw a boom in dam building in the first decades of the 20th century, as engineers threw up walls against the waters in unfamiliar terrain and on a scale never before attempted. They did so in large part by guesswork and extrapolation from much smaller projects. Ambition outpaced knowledge, and inevitably some of the new dams failed-most catastrophically the St. Francis. But its collapse left an important legacy: the world's first dam safety agency, uniform engineering testing criteria and a state-mandated process for arbitrating wrongful-death suits still used today. Too late for Mulholland: "I envy the dead," he intoned at the inquest, and faded into seclusion.