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NPS Form 10-900 OMB No. 1024-0018
(Rev. 8-86)
United States Department of the Interior
National Park Service

National Register of Historic Places
Continuation Sheet

Section number 8 Page 12

St. Francis Dam (Site of), Los Angeles County, California — Narrative Statement of Significance
[continued]
Perhaps the single most significant deficiency of the design, however, was the lack of contraction joints to accommodate the thermal
stresses and shrinkage resulting from the curing of Portand cement. A poorly understood phenomena at the time, thermal stresses in
the completed dam resulted in the need to fill a number of expansion cracks in the face of the dam within a year after its completion.
A more complete understanding of these and other geological and engineering issues related to the design of concrete gravity arch
dams emerged in the years following the St. Francis Dam disaster. [Rogers, 1995: 33-4]

All of this engineering and geological knowledge came too late for Mulholland, and accordingly, the St. Francis Dam disaster would
prove to be an immediate and fatal blow to his reputation as one of the nation’s leading water engineers. In Mulholland’s final annual
report to Board of Water and Power Commissioners in July 1928, he referred to the St. Francis Dam disaster only in terms of its
impact on the city’s water supply, which he considered to be negligible in the immediate term. Shortly afterwards, he took leave of
his position at the city. The following March, he was replaced as chief of the newly reorganized Department of Water and Power. His
successor was his old protege, Harvey Van Norman. [Annual Report, 1928; Mulholland, 2000: 327]
The last standing section of the dam, as well as the largely intact western wing dike, were destroyed by the City of Los Angeles
within 18 months of the disaster, and the more prominent blocks of concrete hammered and dynamited into unrecognizable masses on
the canyon floor. A new road to Powerhouse No. 1 breached what remained of the western dam abutment. Powerhouse No. 2 was
rebuilt in 1928 on the foundations of the original swept away by the flood, as was a nearby employee’s village. Otherwise, little was
permitted to remain on the site of the St. Francis Dam to remind a visitor of the events of March 12-13, 1928. [Rogers, 1995:
80-81]

The need for local water storage would be served by a replacement reservoir constructed in 1932-4 in nearby Bouquet Canyon. This
new reservoir was retained by an earthen dam. [Hoffman, 1981: 260]

Property Damage and Loss of Life
The official death count for the St. Francis Dam Disaster was 420 individuals, although this figure would of necessity be an estimate.
Numerous victims were likely never found, and some amount of double-counting may also have occurred. In any event, conservative
estimates of fatalities in the range of 400 to 450 persons safely establishes the St. Francis Dam Disaster as one of the most costly in
terms of life in California history, second only to the San Francisco Earthquake and Fire, and easily the largest of human origin.

The best available estimates of property losses included eight miles of Southern Pacific Railroad right-of-way and four railroad
bridges damaged or destroyed, nine-hundred nine buildings were destroyed and 331 were damaged. Over 23,000 acres of land, including
nearly 8,000 in agriculture, were considered lost. [Figure 14]

Ironically, the single largest landholder in the path of the flood was rescued from nearly certain insolvency by the disaster. The
Newhall Land and Farming Company received a $737,030.59 property damage claim settlement from the City of Los Angeles in
1930. This check came at a moment when the company was struggling to recover from the twin effects of a crushing debt and the
onset of the Great Depression. The timely income returned the company to solvency, and in the decades thereafter, it went on to
become one of the largest real estate developers in California, with a market capitalization in January 2004 of $986 million.
[Newhall, 1958: 87]
In the aftermath of the flood, a group of enterprising Santa Clara Valley aviation enthusiasts pooled their resources to acquire flooded,
formerly agricultural acres adjacent to the riverbed, where they founded the Santa Paula Airport in 1930. Today, it is the only
private-public use airport in Ventura County, as well as the county’s oldest airport. [Hayes, 1980]