ST. FRANCIS DAM FAILURE

THE ST. FRANCIS DAM PROJECT

• Project of the City of Los Angeles Bureau of Water Works and Supply (Chief Engineer William Mulholland)
• Purpose: To supply an extra 38,000 acre-feet of storage to the Los Angeles-Owens Valley Reservoir
• Construction began in 1924
• Construction finished on March 12th, 1926. Initial filling completed May, 1926
• Projected to supply LA with a years worth of water

THE PROJECT (CONT.)

• Dimensions- Height: 205 ft. (Added to twice)
• Width: 700 ft. at widest point
• Thickness: 150 ft. at base (Added to once)
• Volume: Up to 12 billion gallons of water
• Location: 40 miles northwest of Los Angeles

WILLIAM MULHOLLAND

• The Chief Engineer of the St. Francis Dam
• General Manager Los Angeles Department of Water and Power
• Rose to fame by revolutionizing the water supply of a growing LA
• Was the engineer of the Los Angeles Aqueduct
• Renowned for his cost-effectiveness and timeliness

WHAT HAPPENED?: THE SETUP TO DISASTER

• Dam was at full capacity six days prior to failure
• During building, Mulholland added height to the dam without greatly altering the thickness
• Mulholland called to inspect a leak of muddy water on right abutment
• Believed to be loose soil from a new access road; no action taken
• Around midnight on March, 12 1928, the dam collapsed

WHAT HAPPENED?: THE COLLAPSE

• Initial waves of 125 ft. flowed from the dam
• Waves began travelling at 30 mph, accelerated quickly
• Water and large debris traveled south down San Fransisquito Canyon
• Met the Santa Clara River valley, headed west towards the Pacific
• Flood waters traveled 53.5 miles over approximately 5.5 hours

WHAT HAPPENED?: THE EFFECTS

• Debris of the dam found up to two miles from site
• Estimated 450-600 deaths from the floods
• Many bodies were carried all the way to the Pacific
• Mulholland took full blame for the failure, resigned
• Ruined his career and tarnished his reputation

WHY DID IT HAPPEN?

• Paleomegalandslide on the eastern abutment
• Neglect of the crack by Mulholland
• Thickness of dam was not altered when height was added
• Poor rock foundation
• Insufficient inspection of the grounds where the dam was built

St. Francis Dam (Ca. 1927)

St. Francis Dam (Post failure)

WHAT WAS LEARNED?

• The world's first dam safety organization was created
• Criteria for testing the earth before major engineering projects revolutionized
• Major engineering projects should be overlooked by more than one engineer
• Reevaluation of The LA department of Water and Power dams and reservoirs
• These evaluations led to fortifications of many structures, including some of Mulholland's

WORKS CITED

• http://www.kcet.org/socal/departures/columns/lost-landmarks/the-flood-st-fr...
• http://owensvalleyhistory.com/ov_aqueduct1/st_francis_disaster.html
• http://sometimes-interesting.com/2011/08/01/the-worst-u-s-engineering-disas...
• http://en.m.wikipedia.org/wiki/St._Francis_Dam
• "Mulholland, William." Grolier Multimedia Encyclopedia. Grolier Online, 2015.