The Collapsed Dam That Stopped Los Angeles

Los Angeles needed water, and lots of it. It still does. And that water comes from the LA Aqueduct, masterplanned by William Mulholland. The end of his career, though, wasn't such a triumph. This is the story of the St Francis Dam, and the collapse that stopped Los Angeles from taking over an entire valley.
CORRECTION: It actually held back 47 million tonnes of water, 470 times more than I said. I mistook the dam volume for the reservoir volume when researching! Thanks to Josh for pointing that out. For all corrections on this channel: www.tomscott.c...
THANKS TO: Ed from Media Giraffes - go visit his channel for the 4K drone footage! / mediagiraffes
AND THANKS TO: Alex from Drone Gear - go visit his channel for drone reviews and giveaways! / @dronegear
Also, here I am:
FACEBOOK: / tomscott
TWITTER: / tomscott
INSTAGRAM: / tomscottgo

[@Vaquero4382]

I grew up in the valley that the dam collapse devastated. My grandfather helped recover bodies. A handmade sign in Santa Paula, put up the following day, read; "Mulholland must die." I knew people from the Owens Valley, where the water was stolen from, that told me about LA sending in crews to cut down all of the willow and cottonwood trees because they were using "LA's water." Disgraceful.

[@TomScottGo]

I know the Second Cascades - the larger part of the second location here - weren't part of Mulholland's scheme. They're from the 1970s. But they're also a beautiful location, and the smaller cascade next to them is part of the original aqueduct!

[@db1595]

Wow its quite an amazing setting for a video, these America videos are awesome :)

[@EddieHart]

+Tom Scott I assume nobody was killed by the dam collapse?

[@EddieHart]

***** Apparently, according to Wikipedia, at most 431 people died because of the resulting floods. :(

[@0000Tiberius0000]

+Tom Scott You forgot to mention about the fault that was running through the bottom of the valley ( and dam foundations) which was a major cause for the dam to break

[@Certifiable]

+Tom Scott Good timing with Drunk History covering the collapse this week!

[@YingwuUsagiri]

The first time I heard cheap engineer instead of chief engineer and my brain didn't find that wrong in context so it went with it.

[@superconductor6627]

+Niels Schellekens Same here :/

[@dinehut]

+Niels Schellekens Same over here too.

[@potential_dog_eater]

@picknngrinnin smartass

[@Dominik-uv5gx]

@picknngrinnin If there's no difference what is your problem with him saying 'My brain'? You're not only a smartass, you're also a dumbass. Neat.

[@youtub-fj8mu]

@picknngrinnin dumbass It's a figure of speech

[@jmaraf7741]

I was there on a filed trip from a physical geology class at CSULA. Our professor showed us more. That valley is also divided by a fault line that one can clearly see. It divided one side of the canyon from the other side. The type rocks on one side is also made of schist that break apart in layers...especially when wet. We examined the pieces of concrete that can still be found there and it had fragments of schist, wood, branches, etc., because the debris were scraped from the canyon grounds to mix in with the cement. This made the cement used to build the dam of very poor quality.

[@cathyreves1717]

that's just a myth. the concrete was tested many times and always showed to be good.

[@Sam-hc3zb]

@@cathyreves1717 This is really interesting, i wouldnt mind seeing a source from both of you!

[@filonin2]

@@cathyreves1717 He personally examined the concrete in this myth?

[@mediagiraffes]

Honored to work with you brother! This is amazing all of LA needs to see this!

[@TheYaegerjeusmc]

Great work long neck!

[@tech9803]

My grandma lived near Santa Clarita at the time and remembered the dam collapse very well, it killed over 400 people.

[@DontMockMySmock]

As a resident of one of those satellite towns of LA, I found this video super interesting. I've never heard of any of this shit.

[@dontask8979]

Your only going to hear about what Kalifornia wants you to hear about.

[@potential_dog_eater]

@@dontask8979 you mean California

[@m.j.8226]

Dont ask I get what you’re trying to say here but it really isn’t that deep. California is a huge state. Why would it be necessary to know everything about a specific city you don’t even live in. Los Angeles is not the capital. Someone from Syracuse doesn’t need to know every historical fact regarding Long Island, if you get what I mean.

[@digheanurag]

@@m.j.8226 well if you live in it, it’s good to know

[@emilioalban1234]

I’m also from one of those towns (Pasadena), and this is interesting

[@AliJardz]

Epic ending shot.

[@CrazyRoadblockisbae]

Ali Jardz how are you verified?

[@kylorenkardashian5518]

in the industry it's called the money shot

[@dkaloger5720]

KyloRen Kardashian and that’s what called shadow commenting

[@Flyingcar100]

You know if you ever go to Boston you should do a video on the Great Molasses Flood.

[@BariumCobaltNitrog3n]

+Flyingcar100 I believe he did, search his channel for it. Hot sticky burning river of death it was.

[@Anolaana]

+BariumCobaltNitrog3n I can't seem to find it :/ Perhaps it was another channel?

[@BariumCobaltNitrog3n]

Anolaana Seranaar Yes perhaps.

[@samiam619]

Try “The History Guy” channel.

[@dannypipewrench533]

Always nice to hear about William Mulholland, the reason Los Angelees continued to exist beyond 1905. There was a really good Modern Marvels documentary about him and the aqueducts he built. Side note: I have heard there are some canals here in Arizona that feed water into the Colorado River so the Los Angelees canals can continue to draw water from it without completely draining it, which they actually do somewhere near the Gulf of California. Whether this is true I am unsure of.

[@munk00]

It’s weird seeing Tom stand in front of and talk about a place that I drive past almost every day

[@AugustoValentini]

Something like that happened this weekend in Brazil, but the dam held mud instead of water and it's still spreading and destroying cities along the way, the mud will probably reach the sea tomorrow

[@AugustoValentini]

Badatstuff Yup. And btw the dam is 550km away from the sea. Oh! And the mud is kinda toxic, so... yeah

[@AugustoValentini]

Badatstuff I hope so too. Thankfully not many people died compared to the amount of people who lived nearby the place

[@citizenofvenus]

+Augusto Schmitt Actually not a dam in technical terms, but it was a mining reservoir.

[@AugustoValentini]

Gabriel Ovalle In the news they usually call it a dam, but you're right, it was a mining reservoir

[@citizenofvenus]

Perhaps not heavy metals but at the very least iron, gold and silver.

[@piranha031091]

I can only notice the total absence of water in what remains of the retention lake and the valley the dam blocked. Guess the droughts aren't over then?

[@lmpeters]

+piranha031091 Not even close. This winter's El Nino is bringing some much-needed rain, and hopefully will help to replenish reservoirs and snowpack, but it's going to take far more than one wet winter to get everything back to normal.

[@rdecredico]

+lmpeters There is no normal.

[@dinnertimemishap]

+piranha031091 there is no retention lake...

[@CzechAvailabilitie]

+piranha031091 Turns out that building huge cities in the desert isn't a very smart move.

[@dinnertimemishap]

+rdecredico There is no spoon.

[@quillmaurer6563]

So Mulholland recommended maintenance be done 12 hours before the collapse. I wonder if the workers who were to do the maintenance were sent out there expecting to do so, only to find the dam gone. "Let's go fix the cracks in the ... wait, where'd it go? I guess I'll go home then."

[@Vinemaple]

What a find! I always wondered why the Los Angeles valley was full of so many independent cities despite being so heavily and contiguously built up. Tom Scott to the rescue again!

[@Ryan-br6ic]

“Theres nothing wrong with it”-said everyone before a giant disaster

[@jamesrivettcarnac]

No, that's just what sales and marketing here. Quite often the engineering warnings fall on willfully deaf ears. This guy is a special case of stupid.

[@questioner1596]

It's also what people say before there is no disaster. It's not like a movie where we already know from the trailer what disaster will happen; the future is difficult to predict. We need to learn from these mistakes, because it's very easy to make the same ones again (and some mistakes don't end in disaster, adding to our complacency.)

[@questioner1596]

@Anifco67, and to better answer your statement, sometimes people who warn of dangers do know, and are correct to warn people, even if that event doesn't end up happening. Often weather is difficult to predict.

[@generalrubbish9513]

"It's probably okay" It wasn't okay.

[@dmannevada5981]

The eventual collapse of the St Francis Dam and the reasons for it, is the reason no new reservoirs have been built in California in a half a century. The Topography of the state with the science and knowledge of today understands there isn't really any place stable enough to build new dams. In fact, most of the existing dams and reservoirs, if proposed today, would be rejected with today's science and knowledge.

[@kp5602]

What about the Castaic Lake?

[@dmannevada5981]

@@kp5602 I can't speak to any specific Reservoir, but I have read substantial amounts of information from geologists in the past few years, who state the geology is not suitable to build new dams. Theu've also stated, knowing what they know today, the majority of the existing reservoirs, wouldn't be built based on today's standards and knowledge of the topography/ geology.

[@jacobrawlinson12]

I know it's Nevada, but how's the hoover dam's foundation?

[@dmannevada5981]

@@jacobrawlinson12 Not really sure what your question is? Is there something you're intending to reference to?

[@nickolaswilcox425]

@@jacobrawlinson12 probably fine, havent checked anything but from the images and documentaries, that seems like a lot of rock, rock doesnt do the destructive seepage thing

[@elpmurc]

Another factor that contributed to this dam's failure was that just prior to construction the height of the dam was increased ten feet from the original design, from 175 to 185 feet above the stream bed.

[@ianskinner3455]

it was increased twice by 10' as it was nearing construction by most accounds

[@CesarIsaacPerez]

Amazing indeed. I lived in LA 3 years ago and had no idea of all that history.

[@lindab.716]

I have lived here since I was born 64 years ago and had never heard of this.

[@BetsyNap]

Contrary to what this guy said, the entire San Fernando Valley is part of the City of Los Angeles. The exception is the City of San Fernando which on only one square mile in area and the City of Burbank. The San Fernando Valley was annexed into the City of Los Angeles in 1906 in order for the valley to have access to the water.

[@DanielGarcia-vu2md]

Calabasas and Glendale are also not part of Los angeles city but are still in the valley

[@dmannevada5981]

@@DanielGarcia-vu2md That's because they formed after 1906, with Glendale breaking off from Pasadena.

[@P98D]

something similar but with a much bigger scale happened in 1963 in Italy. It was called the vajont dam

[@DigressingNSQ]

Definitely one of your best videos to date!

[@Falcrist]

As a long term watcher... agreed. The scale of the story and the drone shots helped. Of course, it's still missing something. Maybe a catchphrase at the end like... "and that is something you might not have known."

[@PeterBarnes2]

+DigressingNSQ What're you doing here Ronnie? Get back to editing!

[@Toblehrone]

+DigressingNSQ How did you escape MatPat's jail?

[@Mistran5lation]

I'm from LA but am currently in the Midwest at college, and I am mega-jealous of you right now.

[@MaestroOfficial]

+Mistran5lation u dont know how lucky u are to be from LA....

[@Mistran5lation]

Maestro Now that I'm in Missouri, it is becoming ever more apparent.

[@MaestroOfficial]

Mistran5lation x)

[@nemesis962074]

*Me in the OC* “Burbank, Pasadena” hahaha “Anaheim” *Sweats profusely*

Thanks Tom Scott, for let us know some forgotten and beautiful places like this one.

[@geraldmerkowitz4360]

You never cease to amaze me, Tom.

[@BillWiltfong]

For a dramatic song about the collapse of the dam, check out The Saint Francis Dam Disaster by Frank Black.

[@marsdeat]

"The St Francis Dam outside Los Angeles, or rather what's left of it" I was only half paying attention, and so got a little confused by what "it" referred to...

[@Arkhanno]

I always get excited whenever I see a video from Tom Scott appear in my sub box. Great job to everyone involved in making this video and thanks for sharing!

[@Ingestedbanjo]

Those shots of the sprawling cities make me feel really small. I knew America was big, but those shots seemed to make it look as if the whole Earth was covered in suburbia.

[@misslovedog8177]

When i visited Japan this year, it was amazing to see the difference between LA and Tokyo from the sky. I will say though, it's mostly just the area from LA to San Bernadino that has those sprawling cities which cover everything up to the mountains. Most of everywhere else in Southern California is full of mountains or open desert. San Bernadino (the largest county in the US by area) is mostly unihabited land which stretches for miles.

[@GunSongMan]

Wow, a great part of local history I didn't know about. Thanks Tom!

[@ke7eha]

You should go to Lake Owens, or what is left of it, and see the result of Mulholland's and Los Angeles' water thievery. Short version: there's just an empty lakebed there. (may be some water now, what with the recent rain and the shutdown of both LA aqueduct) The water war is the reason why a blasting permit is difficult to get even today in Inyo county and Kern county.

[@michaelsadventures29]

ke7eha Owens Lake is a 4 hour drive from me, only pass by it when going to Lake Tahoe or Mammoth, 10 , 7 hours respectively.

[@bertilfaux4194]

When that dam broke it swept people out from the valley by Fillmore out to the Pacific Ocean. I heard they found bodies as far south as San Diego.

[@jennifermorgan1838]

No bodies were found that far away.

[@hardinrich2610]

@@jennifermorgan1838 That's sure true. It was just media hype of the time.

[@michaelaparicio3182]

The ecological impact of LA's growing sprawl even reached and still reaches the Owens River Valley.

[@JackMasuoka]

Tom Scott does it again... Fantastic video as always :D

[@1FatHappyBirthday]

Thanks for the dam tour and thanks for not taking me to the dam gift shop!

[@themomorain]

LA looks so sad. Just desert, nothing green, all gray. Depressing.

[@isaiahwarlock]

There's lots of very green areas in LA. It depends on the area and the season.

[@ghostintheroom]

this was taken in november (also known as fall) which results in a dead look

[@chiefn.s.p7044]

It is depressing, I live there

[@ClimbingEasy]

Human Erosion

[@murrybrasell4657]

@@isaiahwarlock small pockets, but not trees all in the place and around it, just a little lacking as someone who lives near a lot of green

[@hyperdrivepics]

You just taught me something about where I live. Thanks!

[@benc5221]

"Los Angelees"

[@qwertyuiopasdfghjks]

What? Is that not how it's pronounced?

+Ben C "El Pueblo de Nuestra Señora la Reina de los Ángeles del Río de Porciúncula"

[@ElagabalusRex]

+Ben C Los Angeles is part of that Ancient Greek part of California, it seems.

[@GuyAPerson]

+ElagabalusRex Tell me when you start pronouncing it "Ahn-hay-lace". No one _technically_ pronounces it right anyway. Except for Spanish speakers of course.

[@BariumCobaltNitrog3n]

+qwertyuiopasdfghjks the ending sounds more like "less" than "leez"

[@gebatron604]

so he built a dam which deprived farmers of their water and redirected it to a city, and it didn't even hold ... what a bastard

[@slikrx]

+Guy Potts - They weren't called the water wars for nothing. Water rights in the American West are a complex, horrid amalgamation of priorities and such, and generally screw everyone except the big money players.

[@hardinrich2610]

Mulholland did not "build" the dam or deprive the farmers of anything. They sold their land and at a good price. The city was growing quickly, thanks to the developers and civic boosters, and the Bureau of Water Works and Supply was in charge of keeping the water flowing. As to why it collapsed is the reason we are still debating and investigating 88 years after the fact.

[@linkskywalker5417]

Guy Potts And doesn't LA still suck with water and projects involving it?

[@elias_xp95]

Typical Selfish American Baron in all but name.

[@SorbusAucubaria]

@Derek Well you could say that the congress stole the water from farmers. In a way if it made impossible for those farmers unable to farm anymore, forcing them to sell, even though it was "good" price. They lost their livelihood and if they couldn't find employment etc the money would have been gone quickly.

[@quietquaintandquirkyquadra]

Inspired by your drone footage and editing. Great vid! Peace

[@pandakatiefominz]

The fact Tom Scott made a video on this before Caitlin Doughty is incredible

[@dLimboStick]

Forget it, Tom. It's Chinatown.

[@ThePumas360]

LOVE that movie. My dad and I try to watch it on tv anytime it comes on.

[@TheConnor12500]

Top notch videos Tom, love it. You seem like you have the perfect type of knowledge for university challenge

[@TheHannah280]

I have driven past this dam my whole life and never knew it’s story. I just know it as a landmark to know I am almost home.

[@AdamDTaylor]

I love LA and love this video on its water - great work Tom

[@tyronekim3506]

I wish you head shown a Sharpie outline of the dam where it would be today. That would have made your presentation more visual in awe.

[@jonmacdonald5345]

Tyrone Kim I found it to be rather mild and padantiff in comparison to others!

[@JL0ndon]

This place was behind my house in Valencia California! What are you doing in SCV?!

[@theJellyjoker]

Dam!

[@Angelzbabe89]

Anyone else watching this on the back of watching the latest Ask A Mortician video on the dam collapse?

[@Breakfast221]

Until two weeks ago, I used to live about a 10 minute drive north of the cascades and 10 minutes south of the dam site. Lived there for 13 years, so it's weird to see these familiar locations here on KZbin.

[@delanask]

Come on down to San Diego! Check out Balboa Park or Little Italy or something, maybe I'll learn a few things about my own city. Your channel is awesome btw, and "Things You Might Not Know" is definitely my favorite series of videos.

[@Nhoj31neirbo47]

The debacle that is land and water mismanagement in California specifically and also worldwide is an unfortunate legacy we are leaving for many future generations to grapple with.

[@dmannevada5981]

That's kind of the glass is half empty perspective, isn't it.

[@michaelcooksey7232]

Thank you, I learn something new today

[@tomihawk01]

I keep thinking that some day I'll watch one of these videos and say "I already knew that", but that day still hasn't come.

[@brianorca]

I'd heard about the dam failure, but not how it related to LA's acquisitions.

[@feels6233]

This was surprisingly educational and interesting

[@rogerwilco2]

Hah, I just read up on the Water Wars and the Salton Sea. I hope Tom does an episode on the Salton Sea as well.

[@yonahschlesinger3815]

Hey Tom, I'd love to use the information you've provided as a reference in a school report. Do you have any sourced articles for this? Thanks.

[@crummydustbunny]

I didn't know water supply in Los Angeles played such a big role even back in the 20s!

[@saltydiarrhea386]

Ayyyyy you're in the US! Welcome and enjoy your stay :)

[@turkeysamwich00]

Tom hitting the mark gormley power stance I see

[@SpaceLordof75]

Chinatown, the 1970s movie, is partially based on the water wars. Great movie.

[@dmannevada5981]

Greate entertainment, not that great factually.

[@GadecMinor]

@@dmannevada5981 It was fiction, not documentary!

[@BusketPosket]

I'm surprised (in a good way) that this series is still both informative and fascinating! Many of these 'trivia' projects get either obvious or boring fairly quickly; kudos for having good ideas!

[@brettefantomet]

I thought about The filming and I was like "have Matt gray bought himself a camera drone???" Great filming from those guys

[@brentbraniff]

This was a great video....Like a good lot of yours are. You need your own series on Discovery or BBC or any network wanting to present well written, interesting work.

[@chicknstripz2596]

Wow I live right next to that aqueduct and I never knew this! I’m going to go explore that collapsed dam now!

[@simonstrandgaard5503]

Really cool drone recordings!

[@Inannawhimsey]

You're totally right aboot the light there -- its so harsh & the land looks so...barren?

[@staubach1979rt]

I've often wondered what could have been done if Mulholland had foreseen the dam break 12 hours earlier.

[@mylittledashie7419]

Like Tom said, there might not have been anything to do about the dam itself, but if he'd spotted it was on the verge of collapse, they could've evacuated people from the nearby areas.

[@staubach1979rt]

@@mylittledashie7419 Good point. Did the dam have a spillway?

[@DreamClean]

Such amazing footage!

[@kylorenkardashian5518]

this was very informative, thank you

[@maxnye5693]

Do a video on the Oroville dam and it's recent rebuild

[@HSMiyamoto]

I know it wasnt the focus of your story, but photos of the damage from the incredible flood that flashed across all the homes and farms from St. Francis Canyon to Ventura deserved to be included. The collapse of the St. Francis Dam illustrate how suddenly deadly an engineering failure can be.

[@concerned1313]

Know about it well. Good, short and accurate video!

[@BadKarma714]

Anaheim is in Orange Country not L.A. County

[@Etaukan]

That terrain looks very familiar--is that the valley where they filmed the pilot episode for Firefly? I imagine one arid, hilly spot looks a lot like the next, but even so, I'd swear that's Whitefall.

[@gailbrocksom433]

Another entertaining, informative and educational video. Lord Reith would have approved.

[@councilofmonkeys3331]

Incredible drone shots. Would expect to hear it buzzing on your audio track, but no. Impressive.

[@councilofmonkeys3331]

...on second watch I see how you did it. :P

[@gwenynorisu6883]

Sabrina Mulholland-Jjones?

[@glennzone12]

Based Tom

[@ricksamericana749]

Short, sweet, and accurate, well done.

[@D.Marquez88]

Been there and it was amazing.

[@denni98]

Mulholland forever left his mark on LA. From chief ditch digger to chief dam builder to chief dam disaster maker. Failure can be either be option or perhaps another opportunity to succeed.

[@erich84502a]

Owens Lake is empty because of LA's needs. How much smaller would LA be with water from the North?

[@dylancampbell8671]

Neat. I live really close to here. I take bouquet canyon all the time

[@DANNYonPC]

Guy named something-Holland does a lot with water, classic

[@Onward_and_Rword]

alex's stance is so powerful

[@shmupshmuppewpew5260]

Underappreciated rock hero Charles Thompson (aka Black Francis/Frank Black) has written two great songs bout this topic... "Ole Mulholland" and "St. Francis Dam Disaster." Have a listen!

[@digitalranger4259]

And you spoil the drone shot with an ad for the other folks' channel.... Great video. Not too many people remember how LA gobbled up the other towns.

[@Hebrew_Loc]

Funny that Mulholland was the last unqualified, uncertified and non degreed Chief Civil Engineer the city of L.A. ever had, or any city for that matter, infact the city of L.A. and the Water Resource dept became so worried about his work the Hollywood Dam/Reservoir was lowered to 1/3 of it's original capacity because it was identical in look and design as the Saint Francis dam, also the Federal government which had been working with Mulholland as a design overseer, and chief consultant in the Hoover Dam went back and had all his notes checked by real bachelored and mastered degreed engineers and certified civil engineers putting a vote of no confidence in Mulholland, but there are still 6 of the 7 dams standing around the L.A. built by Mulholland.

[@zamrock19]

This video was too awesome!

[@inyo56]

More and longer drone shots of the abutments and slide area would have been more interesting.

[@stenbak88]

You make amazing material

[@OlafoWaffle]

+Tom Scott did you guys get special permissions to fly in that area? From what I've been hearing form aviation and GIS friends is that drone pilots need to be licensed and have to talk with ATC towers now.

[@laurenmccord4819]

Just another LA devotee

[@ASilentS]

Chinatown

[@wmpowell8]

This is a very interesting story because I live in one of these neighboring cities: Santa Monica.

[@pigtailsboy]

I've been looking at satellite photos of the western states. They're ruined for lack of water. When a substantial reservoir is nearly dry and has a forest growing in it I think the problem is beyond any ability to cope with. There are so many shallow reservoirs and dry rivers. The west coast way of life seems so entirely hopeless.

[@ChadDominicSahilan]

What a great video!

[@BoxOPirateCrayons]

the rubble there forms a spiral stair case into a giant spherical cave, it's hard to find, but it's on the south end of the rubble i believe