The Los Angeles Water Department decided to build the St. Francis Dam. They wanted extra reservoirs to store some of LA’s water since the other aqueducts were being bombed by the Owens Valley. It took 2 years to complete the project. 

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.     The St. Francis Dam was created as a reserve for water in case the Owens Valley bombed more of LA’s reservoirs, which supplied Los Angeles with its water. The St. Francis Dam was large enough to supply LA with water for an entire year. Although San Francisquito Canyon was not the geographically ideal place to build the dam, fewer people lived there compared to LA, which resulted in the price of the land being cheaper. However, workers soon noticed that the land they were building on was unsteady. One side of the rock didn’t seem completely solid, while the other looked “kind of greasy” to the workers. Also, before the dam collapsed, some cracks were forming in the concrete that made up the dam. Even though the workers were already unsure about the dam, they were still ordered to build it. In the end, the St. Francis Aqueduct turned out to be 208 feet tall and could hold 12.4 billion gallons of water.

The blueprint of the St. Francis Dam’s wall. The gray area is the part that stood after the collapse. On the bottom, it points out where the foundations were, and where the rocks were after it collapsed.

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Next Slide: Stories of the St. Francis Dam Disaster