HISTORY LESSON: The St. Francis Dam Failure

This is a story that very few people know about, a chapter in the history of California in their endless quest for water and irrigated land that has been forgotten on the dustbin of time.

The name Mulholland still graces parts of Los Angeles, and he was the mastermind behind the growth of a small dusty mission settlement into one of the largest cities in the world. Some may curse Mr. Mulholland for this today as they sit in heavy traffic on the 10, the 101 or the 405.

Mulholland was in charge of the Los Angeles Department of Water and Power, and for his time, he was a visionary, as well as a water thief who destroyed towns like the Owens Valley in Eastern California. No distance was too great for Mulholland to get water to both the Los Angeles basin as well as the San Fernando Valley. He was a self-taught engineer from Scotland who had some amazing ideas, including keeping water underground because the dry air of the southwest was an issue with regard to evaporation.

But this isn't a biography of Mulholland, this is a story of hubris, tragedy, and the stubbornness of one man who refused to pay attention to geology, and that some places are not good places to build dams.

“Almost from the start, the St. Francis Dam seemed prone to leaks. Just small ones, nothing too serious, even if folks in the farm towns downstream used to joke they'd see you later "if the dam don't break."
The St. Francis was the big dam that William Mulholland, Los Angeles' chief water engineer, needed to protect the city water system. His aqueduct from the Owens Valley passed through the rift zone of the San Andreas fault. The dam was meant to hold a two-year supply of water in case a quake cut the aqueduct.
Mulholland chose the location in San Francisquito Canyon, five miles upstream from today's Six Flags Magic Mountain theme park in Valencia. He designed the dam. And when it sprang ominous new leaks the morning of March 12, 1928, it was Mulholland who inspected and declared the concrete structure fit.
That night, the St. Francis shuddered and broke apart. A wall of water 10 stories high plunged down the dark canyon, sweeping homes, cars, mud and huge slabs of soaked concrete toward sleeping towns. The flood and tumbling debris hit the Santa Clara River at 18 mph, then followed the riverbed to the sea, washing over bridges as it sped through the dark.”
articles.latimes.com...

Please watch this video for a visual as to what happened, courtesy of the History Channel:
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The dam, which actually failed from the cracks in the rocks in San Francisquito Canyon which were not good for keeping water back, was not an earthen dam. It failed, a hundred foot wall of water went down suddenly in the dead of night killing hundreds asleep in their beds, and the bodies washed out to sea, some found as far down as San Diego.

St. Francis Dam Before:
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St. Francis Dam After:
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I offer this as a history lesson. Earthen dams were NEVER meant to be permanent. They tend to silt up and the holding capacity is much lower as the years go by. In the right circumstances, as we are seeing in Oroville, California, the earth which looks solid turns to mud and starts to be scoured away. This has been a crazy year for very high rainfall in Cali, as we all know. Even if this dam holds up now, California is going into spring and that huge snowfall will melt into the Feather River, causing yet another issue with pressure and overflow with this dam.

I have friends there, I lived in various parts around there for 10 years. I enjoyed Oroville's fishing, swimming and renting patio boats to drink beer and get a sun tan. To see a mandatory evacuation in case of dam failure is difficult, because Oroville is the county seat of Butte county and will mostly be washed away.

Our infrastructure has been ignored for too long. The earthen dams are all old and silted up. The levees protecting Sacramento, the most flood-prone city besides New Orleans, have not been kept up properly by the Army Corps of Engineers, some of them almost 100 years old.

Here is the front page of the Los Angeles Times on March 14, 1928.
tinyurl.com...

The dam, which actually failed from the cracks in the rocks in San Francisquito Canyon which were not good for keeping water back, was not an earthen dam. It failed, a hundred foot wall of water went down suddenly in the dead of night killing hundreds asleep in their beds, and the bodies washed out to sea, some found as far down as San Diego.

I offer this as a history lesson. Earthen dams were NEVER meant to be permanent. They tend to silt up and the holding capacity is much lower as the years go by. In the right circumstances, as we are seeing in Oroville, California, the earth which looks solid turns to mud and starts to be scoured away. This has been a crazy year for very high rainfall in Cali, as we all know. Even if this dam holds up now, California is going into spring and that huge snowfall will melt into the Feather River, causing yet another issue with pressure and overflow with this dam.

I have friends there, I lived in various parts around there for 10 years. I enjoyed Oroville's fishing, swimming and renting patio boats to drink beer and get a sun tan. To see a mandatory evacuation in case of dam failure is difficult, because Oroville is the county seat of Butte county and will mostly be washed away.

Our infrastructure has been ignored for too long. The earthen dams are all old and silted up. The levees protecting Sacramento, the most flood-prone city besides New Orleans, have not been kept up properly by the Army Corps of Engineers, some of them almost 100 years old.

Are we ready to spend our tax dollars on vital infrastructure yet? I hope it doesn't take a massive disaster to show us what needs to be done.

PS...If anybody can help me post pictures and videos, please help!! Things have changed so much since I last made a thread.

a reply to: FissionSurplus

Oroville dam isn't going to fail.

The spillway will and is, but that's it, the dam itself will stay intact.

a reply to: Chadwickus

The rain coming in a few days will once again stress the dam to it's max. It most likely won't fail, but better to be ready for the worst case scenario than think it will never happen.

originally posted by: Vector99
a reply to: Chadwickus

The rain coming in a few days will once again stress the dam to it's max. It most likely won't fail, but better to be ready for the worst case scenario than think it will never happen.

no it won't..

the water level in the lake has dropped by feet..

the rain at .5 to 1 inch will be effectively 2 to 3 inches at the lake..

stressed "to the max" would have to be many more feet of water.

a reply to: Reverbs

Yea but that giant hole in the primary spillway is going to get a lot worse and fast.

I was in Sacramento about 20 years ago during one of the their big floods.

During the dry periods, the overpass rose over the river I would guess about two stories. On each side, there was about 1/2 block of bike paths and a little wooded area before the levy walls. It was amazing to see the water fill in all the way to the levy walls and was literally inches from the overpass.

Sacramento is the city to worry about. One big earthquake in the Bay area can break the Folsom dam. Basically, a huge bowl of water would spill over the city in minutes.