photo of St. Francis Dam The collection of J. David Rogers
The downstream face of St. Francis Dam on March 12, 1928, the day before it failed.

Since 1966, ASCE has designated over 280 projects as National or International Historic Civil Engineering Landmarks as part of its Historic Civil Engineering Landmark Program. Some of these landmarks – the Brooklyn BridgeEiffel Tower, and Hoover Dam – are well-known, while others are less prominent.

The St. Francis Dam failure, which caused the deaths of at least 432 people, is not one of these designated projects but can be considered as instructive as many landmarks. Engineers frequently learn more from failures than from successes. So, with that concept in mind, here are five things you didn’t know about the St. Francis Dam Failure:

  1. The St. Francis Dam failure ranks as the worst U.S. man-made disaster of the 20th century. The reservoir, which had a storage capacity of 38,168 acre-feet, was within a few inches of being filled for the first time when the dam failed catastrophically on the night of March 12-13, 1928. The peak flow of the outbreak flood reached about 1.7 million cubic feet per second, emptying the full reservoir in just under an hour.
  2. City of Los Angeles Bureau of Waterworks and Supply (now the L.A. Department of Water and Power) constructed the dam from 1924 to 1926 under the direction of longtime Chief Engineer and General Manager William Mulholland. St. Francis Dam was the second concrete dam built by the city and was essentially a duplicate of the Weid Canyon Dam in the Hollywood Hills, which was renamed Mulholland Dam (Hollywood Reservoir) a year before it was completed in March 1925.
  3. Mulholland had developed a reputation as a problem solver and for getting projects built on time and within budget. He personally selected the site for St. Francis Dam about five miles up San Francisquito Canyon, based on a nice V-shaped narrows in the canyon. Mulholland’s directive to his engineering staff was to take the basic design for Mulholland Dam and adjust the upstream arch radius to fit the San Francisquito Canyon site.
  4. There are no records of geologic or geotechnical investigations at the dam site, except for simple percolation tests of hand-excavated holes and a few exploratory adits extended into both abutments. The dam site was later determined to be a small portion of an enormous prehistoric landslide complex.
  5. In the subsequent political furor over the disaster, Mulholland accepted personal responsibility for any shortcomings of the dam’s design. At the coroner’s inquest, he famously said: “Don’t blame anybody else, you can just fasten it on me. If there is an error of human judgement, I was the human.” He resigned from his position a year and a half later and carried the burdens of his misjudgment with him for the rest of his life.

Members of ASCE’s History and Heritage Committee have been learning fun and interesting facts about HCELs around the world to share in the new “5 Things You Didn’t Know About …” series. As the committee continues to build an inventory of all HCEL projects, members of the committee and other volunteers have been visiting sites to photograph landmarks and ASCE plaques as well as assess their conditions. If interested in volunteering to help the committee record these landmarks, please contact committee chairman David Gilbert ([email protected]).

Learn more about the committee’s work and the ASCE landmark program.