Mar-12: The Wonders of Science and Man Made Disasters

1928

St. Francis Dam Collapse

The St. Francis Dam was a curved concrete gravity dam, built to create a large regulating and storage reservoir for the City of Los Angeles, California. The reservoir was an integral part of the city’s Los Angeles Aqueduct water supply infrastructure. It was located in San Francisquito Canyon of the Sierra Pelona Mountains, about 40 miles (64 km) northwest of Downtown Los Angeles, and approximately 10 miles (16 km) north of the present day city of Santa Clarita.

The dam was designed and built between 1924 and 1926 by the Los Angeles Department of Water and Power, then named the Bureau of Water Works and Supply. The department was under the direction of its General Manager and Chief Engineer, William Mulholland.

At two and a half minutes before midnight on March 12, 1928, the dam catastrophically failed, and the resulting flood took the lives of as many as 600 people.The collapse of the St. Francis Dam is considered to be one of the worst American civil engineering disasters of the 20th century and remains the second-greatest loss of life in California’s history, after the 1906 San Francisco Earthquake and fire. The disaster marked the end of Mulholland’s career.

From the Los Angeles Times

Mulholland’s distinguished career was over. He resigned seven months later at age 72, depressed and ill from Parkinson’s disease, and died sad and broken in 1935. New inquiries in the 1990s shifted the blame for the St. Francis to an ancient landslide, undetectable even by the most accomplished geologists of the 1920s.

2011

Fukushima Meltdown

The Fukushima Daiichi Nuclear Power Plant is a disabled BWR nuclear power plantlocated on a 3.5-square-kilometre (860-acre) site in the towns of Okuma and Futaba in the Futaba District of Fukushima Prefecture, Japan.

The plant suffered major damage from the magnitude 9.0 earthquake and tsunami that hit Japan on March 11, 2011. The incident permanently damaged several reactors making them impossible to restart. Due to the political climate, the remaining reactors will not be restarted. The disaster disabled the reactor cooling systems, leading to releases of radioactivity and triggering a 30 km evacuation zone surrounding the plant; the releases continue to this day. On April 20, 2011, the Japanese authorities declared the 20 km evacuation zone a no-go area which may only be entered under government supervision.

In April 2012, Units 1-4 were decommissioned. Units 2-4 were decommissioned on April 19, while Unit 1 was the last of these four units to be decommissioned on April 20 at midnight 00:00 Japan Standard Time. In December 2013 TEPCO decided none of the undamaged units will reopen.

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