The St. Francis Dam Disaster

Rewinding History

With Mulholland's resignation and restitution paid by the City of Los Angeles, there were those committed to forgetting the embarrassing failure as soon as possible.  For those who wanted more answers, memories faded and official records were often hard to obtain while myths became realities.

One local historian, Charles Outland, had witnessed the St. Francis flood as a teenager.  Fascinated with the tragedy for more than thirty years, in 1963 he wrote the first full study of the failure, Man-Made Disaster: the Story of the St. Francis Dam.  Outland was no apologist for the role of Los Angeles in the catastrophe, his book is a careful and dispassionate examination.  Aided by Outland's papers, we will learn how this Santa Paula rancher became a dogged historian, painstakingly piecing together the evidence, often against fading memories and official opposition.

Outland's 1963 book and the results of the investigations in 1928 are important, but the science of geology and the technology of dam construction have made dramatic strides since then.  Drawing upon a distinguished panel of historians and engineering authorities,and the results of fresh research found in my book Floodpath, our documentary will take an updated look at the disaster, scientifically, as well as socially and politically.  An especially important source for this will be the work of consulting engineer J. David Rogers who has studied the St. Francis story for more than 25 years.

Although it is generally agreed that geological conditions at the site and inadequate construction techniques were major contributing factors to the collapse of the St. Francis Dam, understanding exactly how it happened is a fascinating detective story.  We will follow the clues for answers.  Just what happened in the surrounding geology that caused the failure?  Should Mulholland have known better? Is there anything he could have done?

One of the most dramatic pieces of visual evidence from the disaster is the reservoir water level chart, or Stevens Gage.  It drops precipitously at 11:57 AM, a startling indication that the dam was down.  But a gradual fall had begun hours beforehand. This would indicate a large outflow of water, but none of the survivors below the dam reported such a pre-flood.  What is the Stevens gauge recording?  The answer is chilling.  In fact, in response to weakening abutment support, the enormous concrete structure was lifting, twisting and tilting, causing the water level to drop against the upstream side of the dam.

And what accounts for the unexpected survival of a single center strip of concrete, and the final resting-places of huge portions of debris, some weighing tons, found far downstream?  Investigators beginning as early as 1928, as well as the work of Outland and Rogers have helped unravel the mystery.  With the help of dramatic photo-realistic 3-D graphics, we will rebuild the St. Francis Dam and experience the collapse and the results of the investigations that followed.