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World Environmental and Water Resources Congress 2017 379

Who Designed the Ill-Fated St. Francis Dam?

J. David Rogers, Ph.D., P.E., P.G., F.ASCE
1

1 Professor and K.F. Hasselmann Chair in Geological Engineering, Missouri Univ. of Science
and Technology, Rolla, MO 65409. E-mail: rogersda@mst.edu

Abstract

The St. Francis Dam was built by the City of Los Angeles Bureau of Water Works and Supply
(BWWS) in 1925-26 as a curved concrete gravity dam, approximately 200 feet high in San
Francisquito Canyon, about 35 miles northeast of downtown Los Angeles. The reservoir provided
an additional 38,000 acre-feet of storage from the Los Angeles Aqueduct. The dam failed
catastrophically on March 13, 1928, killing at least 432 people, making it the most deadly American
structural failure of the 20th Century. BWWS Chief Engineer and General Manager William
Mulholland accepted complete blame for the failure, but who actually designed the dam has been
clouded in mystery for almost 90 years. Recent research suggests that no site-specific rational
design methodology was actually performed, only visual comparisons with some published cross
sections of then-existing dams. More than a dozen separate investigations of the failure followed,
all of which failed to ascertain the dam’s actual maximum cross section or the fact that there were
no stability calculations undertaken as part of the design. Recent evaluations have demonstrated that
the St. Francis Dam exhibited extremely low safety factors in at least five different failure modes,
including internal instability, overturning, arching, keyblock uplift, and reactivation of a
megalandslide on the dam’s left abutment

INTRODUCTION

A careful review of the 847-page Los Angeles County Coroner’s Inquest into the Failure of the
St. Francis Dam in March 1928 (LA Co Coroner, 1928) was made in 2009-10, while the author
served as a Trent Dames Civil Engineering Heritage and Dibner Research Fellow at the
Huntington Library in San Marino, California. Prior to this the author had spent several decades
researching the St. Francis Dam failure (Rogers, 1992; 1993; 1995; 1997, 2006; and 2007).
The nine jurors were comprised of prominent engineers and contractors from Los
Angeles, each volunteering their services for nothing. They included Los Angeles hydraulics
engineer Irving C. Harris (foreman), mining engineer Sterling C. Lines, structural engineers
Blaine Noice, Oliver G. Bowen and Chester D. Waltz, general engineering contractor William H.
Eaton, Jr., real estate appraiser Harry G. Holabird, contractor and insurance executive Ralph F.
Ware, and Z. Nathanial [Nate] Nelson.
Although none of the Jurors appears to have had any formal expertise in geology or
foundation engineering, they possessed considerable technical training in civil/structural
engineering and heavy construction, which is revealed in the technical content of their inquiries
and the timeless wisdom of their concluding recommendations and findings, which have been

quoted in countless articles, standards, and publications relating to dam safety, which advanced
the need for external peer review of dams and establishment of the nation’s premier state dam
safety agency, the Division of Safety of Dams (DSOD) of the California Department of Water
Resources (DWR).

World Environmental and Water Resources Congress 2017