Hey, everybody, This is Chuck Hello, New York. Specifically, I'm coming out there next week, next Tuesday, to perform as a part of UH, the We Knows Parenting podcast. My buddies Beth Newell and Pete McNerney. Pete, He's Peter. What am I talking about? Uh? They're performing live We Knows Parenting for the first time at Little Fields in Brooklyn on Tuesday night, and I'm gonna be there. I'm coming up for this. I'm gonna take the stage with them. I'm gonna talk kids, and it's a good chance to uh to say hi. Emily is gonna be there to everyone, So come on out if you are in the New York area Tuesday. That's this Tuesday at Little Fields in Brooklyn. Go to We Knows Parenting dot com and buy tickets there and UH, I would love to meet you. So come on out and say hello. Welcome to Stuff You should know, a production of I Heart Radios How Stuff Works. Hey, and welcome to the podcast. I'm Josh Clark, There's Charles w. Chuck Brian, there's Jerry over there. And this is part due the sequel of Hoover Damn. Let's find out what happens. So I think the last thing I said was they poured the last bucket of concrete on and the end, so let's do listener mail. Okay, I'm getting definitely worth the two part um. Okay, Chuck. So they poured the last bucket of concrete, they grouded everything off, and all of a sudden, you now have one solid sheet of damn, Hoover, damn, and um. At the bottom, it's much much wider than it is at the top. It's like six plus feet at the bottom, that's how wide it is. At the top is forty five, which still feels substantial. And indeed it's enough to have a two lane highway going over it, and for a very long time, for sixty something years, I've leave that was how you got um from Arizona to Las Vegas. You had to drive over the Hoover dam on top of it, which seems just about as bone headed as it gets. But I guess they were. They were They really wanted the gift shop money from everybody they could get their hands on. Yeah, it was kind of cool to have been forced to do that, because whether you liked it or not, you were gonna see an amazing thing. Um. But eventually, like you, like you were hinting at, traffic just picked up and picked up and they're like, you know what, this isn't great to have all these cars um driving over this thing every day. So let's build a bridge. You know what we'll do. Let's build the longest concrete gravity arch bridge on in North America. Which is appropriate because again, if you take a gravity arch bridge and lay it on its side, you've got basically the Hoover Dam right there. Yeah. So it spans over a thousand feet about a thousand sixty feet of the Black Canyon, just south of the old Route, nine feet above the canyon. Have you been to this bridge? Yeah, it's cool, Like I have driven over that bridge since I visited the damn itself in ninety six. And you get a great view from up there, yes, you do. You also get to experience the most terror you can possibly experience on a bridge because the railing is like less than five ft tall. There's no big barrier, there's no nuts, there's no nothing. It's just void right on the other side. It's so scary. But yes, the view is is unparalleled. I don't think you can walk across it, though, can you Yes, you can, Yes, I had no idea. Oh yeah, there's a no, there's a pedestrian walkway and the railing is less than five ft. I didn't notice that. Oh yeah, that's that's why you weren't terrified. You you walk across this thing and it is so scary. Oh my gosh, it's scary. But it's really really amazing, like the most amazing views of Hoover dam Um. Prior to the bridge opening. We're all done like from about this vantage point by helicopter. Now, any smoke can just walk out there, just park and walk and and see it yourself, and it's pretty amazing. You see all sorts of rainbows. We saw a bunch of rainbows while we were there, because the water is flowing out of the damn outlets and um, the sun shining and there's just rainbows. Like you can't you can't throw a rock and not hit a rainbow around there. Well, Bob mould would end up writing a great song, uh, after being inspired by a visit. There a rainbow connection. No, he Bob Moulden remember Sugar sure and Whisker do. Yeah, but Sugar was his band in the early nineties. And uh, he had a great song called Hoover dam I didn't not standing on the edge of the Hoover Damn. That's such a good bob mole. So March one, believe it or not, they finished this thing under budget two years ahead of schedule. Um, yeah, I want to say something about that real quick. Remember they called Frank crow the the guy who was running was the project manager for the whole thing. Crow. They called him hurry up Crow's right. So he um made the company eight million dollars. Remember how they bid the thing out at just twenty four grand over cost. By coming in under budget and that early, they saved eight million dollars. So he was he was quite the hero for the corporate overlords, old slow money bags. Crow right. So finally the moment comes, and I can't imagine what this must have been like, but they were able to release that Colorado River that had been on hold, we'll not on hold, but flowing in a different place all those years, back into that original route. And all of a sudden you have Lake Mead, the Lake Mead Reservoir. It is um a hundred and ten miles stretching a hundred and ten miles upstream from the Hoover Dam and attracts ten million people a year two water, ski and sun and boat and do fun things. Yeah. Because again it was the designated as the nation's first national recreation area, recreation, recreation, recreation. Uh, it's the biggest reservoir in the world and um, which is saying something because there's some gigant or reservoirs out there. Yeah, this one is one point to four trillion cubic feet. They so there's so much water in their chuck that they measure it by acre feet, which is how much water it takes to flood an acre a square acre of land. And there's something like twenty eight million acre feet in in Lake Mead at its capacity. That's a lot of flooded acres. As a matter of fact, it's like twenty eight million square flooded acres of water right there. That's a lot of water. Yeah, And like me decide we should probably go over some of them, some of the stats for Hoover Damn itself, because it's it's done now. It's the um at the time was the tallest damn in the world by more than three feet um seven six ft from the canyon floor. And now it is the second tallest still the second tallest concrete gravity damn in the United States, behind the Araville Dam in California, which I don't know if you looked at that, but it's no Hoover dam Oh is it schlubby? I mean it's fine. Looks like a big giant slipping slide. It's got this huge ramp. Yeah, it's fun. But again, Bob Mule didn't write a song called the Araville Damn. Can I hear a little snippet of it? If you have no no, no, no no, just just play the first one again and I'll do this. Aura Ville's so good Today Hoover Dame is still uh second in the country in power production and ranks eleventh in the world in power production. It's second in the country still for power. Yeah, for power production. Wow, that's that's that's crazy and the biggest until nine when the Grand Coulee hydro electric Dam in the Columbia River in Washington State took it over, right, right, But so that there and there's still one and two I guess then is the thing that's right. But what's craziest, So the hydro electric power from the Hoover Dam generates like four billion kilowatt hours annually. Okay, that that must be like enough to power the entire US. That's actually not the case at all. Um, it's about I believe quarter or a five of the annual power consumption of just Los Angeles County, just Los Angeles. Um, it's about a of it, but so sure, and it is having a significant impact. I read that if they stopped producing electricity at the Hoover Dam, everyone in California and the Southwest power bills would go up by like a month. That's pretty substantial. Um, but it's it's still I'm I'm I guess I'm saying like I'm surprised it's the number two guy on the block. Still. Yeah. They the way they distribute it to is, Um, California gets about almost fifty of the power. Uh, Nevada, Nevada, they both get, and then Arizona gets about close to n Did they split that yeah, Nevada, Nevada. Yeah, Yeah, but that's only fifty three or fifty seventy three. That's still not I wonder where if the rest where the rest goes downstream the power? Yeah, well no, always so you're talking about the power of the water. The power. Oh, I don't know, because I wonder how much of that operates the damn itself. Can't be that much. I mean, that's a lot left over. I'm not sure. Yeah, I'm not really sure. So, um, regardless of where that that phantom electricity goest Chuck, I want to talk about another extraordinarily foresightful um part of this project. Do you remember when they diverted the river in those four tunnels around the damn project site? What what are you talking about? Well, let's go back. Well, we'll go back and replay the entire episode real quick, and they'll be in there somewhere. So, so they diverted the river so they could build the dam, and they saved those those tunnels. They didn't just like cover them up and say forget you, we don't need you anymore. They said, no, no, no, we can actually use you in the future. So one on each side is now called the penn stock. It's a it's they they've been um encased in steel and then um narrow rowed from fifty ft to thirty ft in diameter, which is still pretty substantial, and they use those to send water from the lake mead to the power station turbines on either side, the Nevada side and the Arizona side, and that's where the hydroelectric power is is generated. So they use the diversion tunnels to generate the hydroelectric power. Now, yeah, it's amazing the water falls into these things. Uh go down about five feet into this power station, which, by the way, part of the tour is you get to go down into the bowels. We miss that, which is kind of neat. Um. Yeah, you didn't about the word bowels just turned you off, So that's why did um. So it falls about five feet into the power station. Uh, it's flowing here at about two thousand cubic feet between two and three thousand cubic feet per second, And anyone who knows what hydro electric power means, all you're doing is using that water to spin turbine and connect that to a power generator and all of a sudden, Arizona, Nevada, and California are getting juice, right, which is pretty ingenious because if you think about it, when when that water is flowing from Lake me down these um these pen stocks to the turbines, they're not using any pumps or anything like that. It's all just gravity um sending it over like a six hundred feet drop and what did you say? It was like two thousand to three thousand cubic feet per second, So that chuck is a lot of water. That is a tremendous amount of water, so much so that converted into big Max per second. You're talking eighty nine thousand, three hundred and sixty seven big Max per second if you're moving water to two thousand cubic feet per second. And that's actually accurate based on the dimensions of big MACA did the calculation. That's how many big Max would be flying past you in a second if if it were big Max instead of water they were sending down there the other stat which staggers me and uh, because I was thinking, like, there's no way Julia actually figured out the horse power of this whole thing, and she did well, she found someone who did, and this thing can crank out almost three million horsepower combined. I know that's a lot of horse power, but I'm just trying to like put it in other terms, like how many how many trains is that We'll just think about standing uh, in the middle of a desert and seeing three million horses charging at you. It's a lot of horsepower. That's a lot of horses. It is so the way that the water gets from Lake Mead down to the turbines, I mean, it's all very much control. And the way they control it is if you ever go to the Hoover Dam, just on the Lake Mead side of the dam, there these four towers that rise out of the water, and those towers have gates that can be opened and closed to let water in. And those are the gates that let the water and that send it to the pen socks down in into to power the turbines and the power stations, apparently to the tune of three million horse power. It is amazing. Again, all of this if you step back and just kind of look at it as a kid, you're like, yeah, put a hole here to make the water go there, to make the turbine spin. It's really simple in a lot of ways. But the amount of ingenuousness it took to actually execute it, that's where the chef's kiss lines. All right, let's take a break here and uh, we're gonna come back and talk about uh spill ways right after this. Alright, chuck. So they used two of the four diversion tunnels to feed the turbines to generate hydroelectric power that leaves to other ones. And I know they didn't just forget about those what are they using those four? And this is sort of the final component here, because what they had to do was, Um, I mean, when this thing is working great, which it almost always has, we'll get to that in a second. Um, everything's awesome. People are getting power, people are waterskiing on Lake Mead. Um, people are getting water, Crops are getting water, cows are drinking water. Everybody's happy. But they did have to think about the fact that the Colorado River used to be quite a bear and may get angry again one day, or this thing may fail one day. So we need to think about what happens if something does go wrong, whether it's a flood or the system breaks down or something. So they thought ahead and they they set up what we're called spill ways. They can actually divert once again, all that water into those two outer tunnels, uh that are now referred to as spill ways. But this is downstream, right right, so not the upstream tunnels that are being used UH for the flibbertyg of its. Have you ever seen a fish ladder? Surely you have, Yeah, we've I think we've even talked about them on something before. Yeah. That's basically like an upstream spill way. Yeah, okay, So this is the opposite that's sending it down, and it's it's it's the exact same principle and almost the exact same design as that little overflow hole that you have in your sink. So like you you can't flood your bathroom because eventually, if that water or level hits that hole, it's just going to go into the hole and down the drain. Anyway, this is the exact same thing. So they utilize those remaining two um diversion tunnels as the spillways, and they didn't lower them at all. Remember they reduced the other ones to like thirty ft from fifty ft. These are still fifty ft spill ways lined with like three ft of concrete. But they follow very similar trajectories where you know, the water hits a certain level on like a flood or whatever, and it goes through these spill ways and then it drops several hundred feet I think six hundred feet, which is a lot for a lot of water to drop. It starts to pick up a pretty pretty high velocity, and then it it all spills out of these gates a little further downstream beyond the hydroelectric plants, and everybody's saved and happy and nothing. No, no waters ever meant to go over the top of the Hoover Dam. If that ever happened, that would be colossally bad. It's never designed to do that. Um, it probably never will do that. Even if humans suddenly just vanish overnight, the spillways would probably still work. But um, that's what it's designed for. Is designed to just get rid of that water and reroute it, basically like they rerouted the Colorado River, but this time they're rerouting it around the power stations which would be swamped with that much water. Yeah, and they don't let it's it's not like they were like, all right, if this gets within like three or four feet, we're gonna take action. If it gets to within they said it at twenty seven feet. So if the water rises for any reason to within that twenty seven feet to the top of where those cards are driving, the spillway gates open up, uh, and it diverts that water and the dam uh is not able to breach, which like you said, would be catastrophic. It let's out a big huray uh. And the good news is the system, that outlet system has never failed uh and it's only had to be used twice once for the test in one and then in nineteen eighty three. It was actually a flood that got within that caused that river to go up within twenty seven feet and they opened up that spillway, which I imagine there was I mean, it was probably kind of scary, but they were probably some engineers that were pretty excited to get to use those spillways finally, Yeah, because they I mean, you would have had to have been an old time or to have been there for the nineteen forty one test by the time three came around. So I'm sure all these people wanted to see this because they they had never seen it work before, and they also wanted to know if it did work. And it definitely worked. I mean it was it wasn't a drill like one. It was a straight up flood like this is what it was designed for, and it worked just fine. Yeah. But both times during the test and during that flood, those spill ways suffered some some damage. So let's talk about the um the failures that have happened over the years. Right. So in those those first few years, when everyone was still kind of biting their nails a little bit, there were there were a couple of problems. Um Air bubbles formed in these spill ways and seepage, like water started seeping under the base of the dam, which is not good at all. No, and those are actually two different things, so both we'll start with the the um air bubbles, right. So that's that's called cavitation. And when the spill ways were used, both in that ninety one test and in the actual flood, when that water, that huge, huge amounts of water fell, you know, six hundred feet down to the elbow of the spill way that led it the rest of the way out to the river um when it hit, when it impacted. By that time, these things called cavitations, a little like bubbles of vapor had formed in the water column. And these things were so strong that when they collapsed they had enough force that they could like shatter concrete. So when this the spill test was done, the spell way test, and then when the flood was over, and the spell ways were turned off. They went and investigated. There were huge chunks of concrete missing. The water had just sheared it away like it was nothing. And the cavitation is still not really fully understood. It's part of like a really um infrequent unusual occurrence like that, like water typically doesn't flow that fast on Earth over you know, a man made structure, so it's not like something we have to worry about. But they figured out that if you insert aer raiders or air ducts something to insert air into that water to kind of lessen the blow kind of pad or pillow the the impact of those cavitations collapsing, it can protect concrete. And so after one they didn't really know what they were doing after somebody had figured out aeration by that time, and so they installed them right afterwards. And as far as I know, they haven't tested it to see if it works, but in other places it's been shown to work, so I think gets a pretty safe bat that if those overflow spill ways have to be used again, they probably won't cavitate because of the aeration that was inserted into the spill ways. Now, yeah, well, I actually saw in forty one they knew that they could do this with air ducks, but the government wouldn't pony up for the money. Oh is there right, Yeah, they denied the funds. And uh it took until that flood of eighty three when it happened again, when the government was like, all right, we'll pay for this stuff. Fine, Hoover's ghost came out for the don't get involved. It's not the government's job to pay for broken concrete. So, um, this seepage was the other was the other sort of engineering failure, and we should, you know, we need to point out that this thing is performed really, really well, Like none of these failures broke the damn. You know, that's a really good point, and I think it's definitely worth pointing out. Like the spill waves those were huge you know where where and tear that that probably shouldn't have happened in probably won't again. But yeah, the whole system still worked. Yeah. So if you have a damn like this, Um, the stability of this whole thing relies on keeping all that water out. So any seepage under the base of that damn is not good. It's gonna cause uplift pressure that's gonna shift the whole foundation, and this grout uh basically was was failing. Um, a grout curtain is going to prevent the seepage. So they were pressure injecting all this grout into these holes trying to fill cavities, but it, uh, it was not and they were getting some seepage in there. Well, they did a really poor job of geological exploration before they ever started the project. Yeah, that was the main issue there. So, like the same grout that they they introduced into those cooling pipes after they were finished building the actual damn itself, they were they were introducing that into these holes they drilled to kind of fill those cracks, crevices, faults, all this stuff that's in the bedrock. Because normally, when the Colorado rivers flowing chuck, it's like it's fine, it's allowed to keep going and it doesn't try to get anywhere aside from the river bed. But when it runs into the dam, then it's got issues. The water wants to go somewhere, right, Yeah, that's what water does. It wants to go somewhere, So it starts to find those little cracks and crevices and faults, and when it fills up enough of them, it can actually lift up the dam, and that's what it was doing, it was lifting up the dam. So they went back and drilled more holes and added even more grout and basically created this barrier. So you've got the barrier that's the dam, and then you have the barrier that's this grout reinforced bedrock, you know, hundreds of feet down into the earth. So now the water just gives up and does what it's told. Yeah, I love that they they really went overboard there and like an additional three feet underground with this grout. But imagine being like the dam is actually lifting up, it's starting to float. That is the exact opposite of what you want to go on with your damn. Yeah, for sure, because apparently on the on the face of the damn, the um upstream face, the water pressing up against it like meat, is over a hundred miles long. It's an enormous amount of water and it's being held back by this one slab of concrete. And I guess I think Julius said it was like forty five thousand pounds per square feet of pressure pressing up against the damn at all times. So yeah, that that um that's a that's just Harry if you think about it, especially then if you start to think about the that amount of that amount of concrete like being lifted up by the water and it's just basically being moved out of the way, and they had to stop it in time. Alright, folks, we're gonna take our last break. We're gonna come back and finish up with part four, Part two of Hoover Damn right after this. All right, we're gonna bring it home here with um or or we could keep talking about it forever, uh, with a little bit on how um the Hoover Damn just really changed the United States and especially the Southwest. UM Roosevelt Franklin Roosevelt dedicated the damn on sept and man insult to injury. Former President Herbert Hoover was not even on the guests list to come from and see that dedication. No, do you mene like four years after and he was the guy who was the first champion of the whole thing too, I mean like it was his project for sure. So uh, that area, that region, it really changed everything, um aside from Boulder City becoming a real place, which is kind of neat in Vegas growing. The whole region was allowed to flourish, um because well one big reason it's because they tamed that Colorado River. No more flooding, right, Um, So no more flooding meant that you could actually have like a stable agricultural um industry, right yeah the area. It says here the region's crops and livestock account for and of the entire country's production. Yeah, and they grow so much like lettuce and cilancho and stuff that that regions now called America's salad bowl. Um. It's a huge, like, it has enormous amounts of production, and it never would have gotten to that that point had the Hoover damn not produced like a steady, reliable supply of irrigation and um done away with flooding. Like there's no more. There hasn't been a single flood from the Colorado River that's affected any of the land in the area since the Hoover Dam came online. You know, when I lived in Yuma and I waited tables at Julianna's patio cafe, there was this this dude, I can't remember his name, but this one guy that would bring in a bunch of big money guys uh to eat every now and then, like six or eight of them for these business dinners. And he was a lettuce guy. Oh yeah, okay, And I just thought it was so funny growing up in Atlanta and never you know, thought about it. But he all he did was grow let us in. If he came in with his you know, six or eight buddies, like you had to shut down and take that table only like he expected you to only wait on your table right. Well, there's some real lettuce in it for you, Oh there was. It was he a good tipper because a lot of times those guys are not well. It was he always had a party big enough to where the tip was included. Um. And he would usually give you give you a little lettuce on top of that. That's nice. Literally, here's a piece of romaine for you. It's good for you, kid, and spank you on the bottom as you were walking away down. Um. So the Hoover Dam changed everything, like Uh, places like Tucson, Arizona would not even have been allowed to happen. Uh in Las Vegas and l A booming like it did, um thanks to the Hoover Dam. Like you said, no flooding tons of production and everything is under control. One thing they did have to worry about, well, we'll talk about what they are worrying about now in a minute. But one thing they did worry about then and then, like in World War two and again at nine eleven, was the fact that it's a terror target because it so many places rely on this for water, the irrigation. That if terrorist organization took out the Hoover Dam especially I mean to be bad anytime, but especially in World War two, it would have been catastrophic. Yeah, so I guess nineteen thirty nine, the Mexican government let the American embassy in Mexico City know, hey, we just heard that the Germans are planning on bombing Hoover Dam, and UM America was like what, And they put up all these new safeguards and got military police to patrol the area. They installed floodlights on Lake Mead, they put up a steel net so you couldn't get anywhere near the um, anywhere near the dam on the Lake Mead side because remember, I mean, people are like boating and recreating on this um. So they had to kind of keep people away from the damn for the first time. And but they still kept going on. You could still go visit and everything, and then Pearl Harbor happened. Um, and they were like damns closed and they closed the damn to the public for the duration of the war, I think until like the end of ninety five they finally opened it to the public again. All because of the dirty Nazis. Yeah, man, and they um they did. The damn itself actually had its own police force. Um. The Army of course came in there to help out as well. But it was a pretty big deal because not only are you disrupting water and maybe flooding the valley, but the power supply to southern California. There was a lot of aviation manu still is a lot of aviation manufacturing in Southern California and for and I think that's what the Nazis were really after, to disrupt the power supply to the aviation industry. Yeah, because at the time America wasn't even in World War Two yet, but we were helping the British with the aviation stuff we were building. So they were trying to strike at the heart of British capabilities by blowing up the Hoover Dam. There, unexpected the Nazis want to blow up the Hoover dam and the US is like, what did we do? We're not even in this so called World war, right, Oh yeah, helping them? It's all right, I got you. We're still not going to let you do it, but now we understand. Uh. And then, of course after nine eleven it was, um, there was a lot of fear that that could be a potential and it still limbs as a potential terrorist target. Well that was one reason why they built the bridge, the bypass bridge, was They're like, you know, this is just too vulnerable letting people drive over it. And so from what I understand, either after um the German bomb plot became evident or after nine eleven, and I think it was after nine eleven until that bridge opened up, when you drove over the Hoover damn you had to wait and it would happen and I guess shifts, and you would be escorted across by the police um in groups of cars, and then you'd be you'd make your way to the other side and they'd be like keep going, don't even look back, or we'll arrest you. Um. And then that's how you got across until they finally opened the bypass, which must have been um up, but there are a lot of delays. Yeah, probably so in that situation. So the current threat, aside from that looming terror threat, is the fact that, uh, there have been about sixteen years of drought in that area, and uh it's scary. Man. Lake meat is not the same. I mean it is what it like a hundred and fifty feet uh lower than it used to be then it wasn't two thousand and thirty feet. I mean that's amaze. That's a huge, huge drop. Yeah, there's like a bathtub ring high water mark. Now it's just the discoloration along the canyon walls where you can see where it used to be, and it's really significant. And the problem is when they built the dam, they built it so that the the gates that um allow water down to the pen socks to the hydro electric plant they cut off at a certain height. After that the water is too low to flow through the gates, and in you have no hydro electric power. Same thing with the pipes that pump water out to Las Vegas and Los Angeles and Tucson and everywhere else that gets water. Um, they're at a certain height too, so once they I think, once the water level hits like eight ft, there's no more water that can be drawn out. And they actually got around this by creating a new low level pumping system to where they came in and went under the under Lake Mead and tapped into it and now just like a bathtub drain at the bottom of a bathtub, there's a pumping station so that that now they're not like, Okay, we have eight water we can't get to to drink from any longer. Now they're like, no, we can. We can get to all the water we need to for um for drinking, which is a huge relief. That's a big, big deal that they were able to do this. But at the same time, everyone's still very much aware that they're like, we still have issues, like we're losing water through evaporation and from um, you know, lower and lower snow accumulations up in the Rockies where all this water comes from in the first place. Like there's a big problem with climate change and it's having an enormous impact on Lake Mead, and because all these areas you know, depend on it for electricity and water, everybody's really freaked out right now, Yeah, so the the current proposition is the l A Department of Water and Power. Um, they have something on the table that it's basically like a loop, a cycled loop system. They said, why don't we do a return path for that water. Put a huge pump station, solar powered pump station downstream that's gonna then send water and cycle it back up to the reservoir. And not only that, I mean it's a pretty good idea. Um. Not only that, it would you could still you know, you could enable more power generation and also create a reserve of electricity for peak periods. So then all of a sudden, the Hoover Dam is like a big battery essentially run by uh, solar power, right, which sounds great. It's like, okay, yeah, why why just let all that water go when you're just generating hydroelectricity from it? You know, put it back. But all the people who depend on that water down stream say, uh, we still need that water. You can't pump it back into Lake Mead. We need that stuff like that's our water. Um. And that's part of the problem with it, Chuck, is that there's so many people who depend on this, not just from Hoover Dam, but there's like multiple damns above Hoover Dam too. So there's a lot of people drawing water for all sorts of different purposes. Um, from the Colorado River. That there's just it seems to be too many. There's just too many people. There's too many, there's too much need. And when you toss in climate change, uh and the impact that the sixteen or nineteen your drought is having, it's, um, it's it's it's a really precarious position right now that they have not figured out. Yeah, pretty scary, man, it is scary for sure. I got nothing else that is surprising because there is a lot to talk about. I've got one more thing. So you said that, um that uh FDR dedicated the place in right? Is that what I said? I believe that's what you said. Everybody, Yeah, that's what you said. So. Um. There is a sculptor named Oscar J. W. Hanton And you know the the winged Art Deco giant figures the statues that are there on site. So he created those. And did you notice the Toronto floor the apron that's in front of those statues. I don't remember. It's okay. So there are these two giant art deco statues. They look kind of like the Oscar Award, but with wings and they're seated and um. They're there to just basically commemorate this conquering of humanity over you know nature. Um. But on the round in Toronto is a star map and it shows the exact position of the stars in the sky on that day in when Hoover Dam was dedicated, So that future generations to come, even if there's like no more Americans and no one speaks English anymore, and this whole area has been abandoned, they could come back and find the Hoover Dam and the star map and calculate the exact day that it was dedicated, just based on the position of the stars and this Toronto floor and that neat. That's amazing, extra little touch there. Learn that on the self guided tour. By the way, yep, if you want to know more about the Hoover Dam, go go to the Hoover Dam. We can talk about it all day long. We could talk about it for two more episodes and it still wouldn't get across what it's like to be there. Uh. And since I said that it's time for listener mail, I'm gonna call this. Uh uh, Well, we got something wrong in deserts or Rival, which, by the way, we got a lot of kudos that that perhaps maybe our funniest episode. That was great. It was a lot of fun. Yeah, we're being silly that day. Those are always good. Hey, guys, been an ABBOD listener for years. Can't thank you enough for the countless hours of entertainment. Despite all the great topics and education, I've never been tempted to write until today. During your Desert Survival opening an immediate and hilariously enjoyable left turn tangent Chuck, you mentioned your tribute to Annie with a reference to food Glorious Food. I feel so dumb. That song is actually from Oliver, which I know. I know that everybody knows. You know that I know Annie and I know Oliver. Maybe they were friends. Could I have school, please, Daddy war books? That's it. That's the big line, um, he said. I thought you might get a kick out of how I know this to be true. When I was about eight or nine, my hometown did a community production of Oliver and I was cast. What part did you play? You may ask, Well, in the song food Glorious Food, there's a line that goes food, glorious food, peas puddings, and save lois. What next is the question, rich gentleman, habit boys indigestion. At the singing of Indigestion, my role and shining moment of the performance was to lean over while the tuba and the orchestra pit let out a deep and juicy note. Yes that's right everyone. I was in the credits as the flatulent orphan. See you get that he bends over in the tuba goes uh got it. Needless to say, guys, my life peaked early. I will always be remembered for that song. Thanks for all you do. That is Eddie in Denver, Colorado. Eddie, that was a fantastic listener mail, good one, like a award winning maybe, ye man, I mean, if you're talking tuba farts, you've got my heart. Yeah you. Eddie just got the Hoover Damn Award for listener Mails, the current Hoover Damn Award older. So thanks for that good one. If you want to get in touch with us, you can go to stuff you Should Know dot com. All of our social links are on there, or you can just send us an email. Send it off to Stuff Podcast at i heart radio dot com. Stuff you Should Know is a production of iHeart Radios How Stuff Works. For more podcasts for my heart Radio, visit the iHeart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.

Hey, everybody, This is Chuck Hello, New York. Specifically, I'm coming out there next week, next Tuesday, to perform as a part of UH, the We Knows Parenting podcast. My buddies Beth Newell and Pete McNerney. Pete, He's Peter. What am I talking about? Uh? They're performing live We Knows Parenting for the first time at Little Fields in Brooklyn on Tuesday night, and I'm gonna be there. I'm coming up for this. I'm gonna take the stage with them. I'm gonna talk kids, and it's a good chance to uh to say hi. Emily is gonna be there to everyone, So come on out if you are in the New York area Tuesday. That's this Tuesday at Little Fields in Brooklyn. Go to We Knows Parenting dot com and buy tickets there and UH, I would love to meet you. So come on out and say hello. Welcome to Stuff You should know, a production of I Heart Radios How Stuff Works. Hey, and welcome to the podcast. I'm Josh Clark, There's Charles w. Chuck Brian, there's Jerry over there. And this is part due the sequel of Hoover Damn. Let's find out what happens. So I think the last thing I said was they poured the last bucket of concrete on and the end, so let's do listener mail. Okay, I'm getting definitely worth the two part um. Okay, Chuck. So they poured the last bucket of concrete, they grouded everything off, and all of a sudden, you now have one solid sheet of damn, Hoover, damn, and um. At the bottom, it's much much wider than it is at the top. It's like six plus feet at the bottom, that's how wide it is. At the top is forty five, which still feels substantial. And indeed it's enough to have a two lane highway going over it, and for a very long time, for sixty something years, I've leave that was how you got um from Arizona to Las Vegas. You had to drive over the Hoover dam on top of it, which seems just about as bone headed as it gets. But I guess they were. They were They really wanted the gift shop money from everybody they could get their hands on. Yeah, it was kind of cool to have been forced to do that, because whether you liked it or not, you were gonna see an amazing thing. Um. But eventually, like you, like you were hinting at, traffic just picked up and picked up and they're like, you know what, this isn't great to have all these cars um driving over this thing every day. So let's build a bridge. You know what we'll do. Let's build the longest concrete gravity arch bridge on in North America. Which is appropriate because again, if you take a gravity arch bridge and lay it on its side, you've got basically the Hoover Dam right there. Yeah. So it spans over a thousand feet about a thousand sixty feet of the Black Canyon, just south of the old Route, nine feet above the canyon. Have you been to this bridge? Yeah, it's cool, Like I have driven over that bridge since I visited the damn itself in ninety six. And you get a great view from up there, yes, you do. You also get to experience the most terror you can possibly experience on a bridge because the railing is like less than five ft tall. There's no big barrier, there's no nuts, there's no nothing. It's just void right on the other side. It's so scary. But yes, the view is is unparalleled. I don't think you can walk across it, though, can you Yes, you can, Yes, I had no idea. Oh yeah, there's a no, there's a pedestrian walkway and the railing is less than five ft. I didn't notice that. Oh yeah, that's that's why you weren't terrified. You you walk across this thing and it is so scary. Oh my gosh, it's scary. But it's really really amazing, like the most amazing views of Hoover dam Um. Prior to the bridge opening. We're all done like from about this vantage point by helicopter. Now, any smoke can just walk out there, just park and walk and and see it yourself, and it's pretty amazing. You see all sorts of rainbows. We saw a bunch of rainbows while we were there, because the water is flowing out of the damn outlets and um, the sun shining and there's just rainbows. Like you can't you can't throw a rock and not hit a rainbow around there. Well, Bob mould would end up writing a great song, uh, after being inspired by a visit. There a rainbow connection. No, he Bob Moulden remember Sugar sure and Whisker do. Yeah, but Sugar was his band in the early nineties. And uh, he had a great song called Hoover dam I didn't not standing on the edge of the Hoover Damn. That's such a good bob mole. So March one, believe it or not, they finished this thing under budget two years ahead of schedule. Um, yeah, I want to say something about that real quick. Remember they called Frank crow the the guy who was running was the project manager for the whole thing. Crow. They called him hurry up Crow's right. So he um made the company eight million dollars. Remember how they bid the thing out at just twenty four grand over cost. By coming in under budget and that early, they saved eight million dollars. So he was he was quite the hero for the corporate overlords, old slow money bags. Crow right. So finally the moment comes, and I can't imagine what this must have been like, but they were able to release that Colorado River that had been on hold, we'll not on hold, but flowing in a different place all those years, back into that original route. And all of a sudden you have Lake Mead, the Lake Mead Reservoir. It is um a hundred and ten miles stretching a hundred and ten miles upstream from the Hoover Dam and attracts ten million people a year two water, ski and sun and boat and do fun things. Yeah. Because again it was the designated as the nation's first national recreation area, recreation, recreation, recreation. Uh, it's the biggest reservoir in the world and um, which is saying something because there's some gigant or reservoirs out there. Yeah, this one is one point to four trillion cubic feet. They so there's so much water in their chuck that they measure it by acre feet, which is how much water it takes to flood an acre a square acre of land. And there's something like twenty eight million acre feet in in Lake Mead at its capacity. That's a lot of flooded acres. As a matter of fact, it's like twenty eight million square flooded acres of water right there. That's a lot of water. Yeah, And like me decide we should probably go over some of them, some of the stats for Hoover Damn itself, because it's it's done now. It's the um at the time was the tallest damn in the world by more than three feet um seven six ft from the canyon floor. And now it is the second tallest still the second tallest concrete gravity damn in the United States, behind the Araville Dam in California, which I don't know if you looked at that, but it's no Hoover dam Oh is it schlubby? I mean it's fine. Looks like a big giant slipping slide. It's got this huge ramp. Yeah, it's fun. But again, Bob Mule didn't write a song called the Araville Damn. Can I hear a little snippet of it? If you have no no, no, no no, just just play the first one again and I'll do this. Aura Ville's so good Today Hoover Dame is still uh second in the country in power production and ranks eleventh in the world in power production. It's second in the country still for power. Yeah, for power production. Wow, that's that's that's crazy and the biggest until nine when the Grand Coulee hydro electric Dam in the Columbia River in Washington State took it over, right, right, But so that there and there's still one and two I guess then is the thing that's right. But what's craziest, So the hydro electric power from the Hoover Dam generates like four billion kilowatt hours annually. Okay, that that must be like enough to power the entire US. That's actually not the case at all. Um, it's about I believe quarter or a five of the annual power consumption of just Los Angeles County, just Los Angeles. Um, it's about a of it, but so sure, and it is having a significant impact. I read that if they stopped producing electricity at the Hoover Dam, everyone in California and the Southwest power bills would go up by like a month. That's pretty substantial. Um, but it's it's still I'm I'm I guess I'm saying like I'm surprised it's the number two guy on the block. Still. Yeah. They the way they distribute it to is, Um, California gets about almost fifty of the power. Uh, Nevada, Nevada, they both get, and then Arizona gets about close to n Did they split that yeah, Nevada, Nevada. Yeah, Yeah, but that's only fifty three or fifty seventy three. That's still not I wonder where if the rest where the rest goes downstream the power? Yeah, well no, always so you're talking about the power of the water. The power. Oh, I don't know, because I wonder how much of that operates the damn itself. Can't be that much. I mean, that's a lot left over. I'm not sure. Yeah, I'm not really sure. So, um, regardless of where that that phantom electricity goest Chuck, I want to talk about another extraordinarily foresightful um part of this project. Do you remember when they diverted the river in those four tunnels around the damn project site? What what are you talking about? Well, let's go back. Well, we'll go back and replay the entire episode real quick, and they'll be in there somewhere. So, so they diverted the river so they could build the dam, and they saved those those tunnels. They didn't just like cover them up and say forget you, we don't need you anymore. They said, no, no, no, we can actually use you in the future. So one on each side is now called the penn stock. It's a it's they they've been um encased in steel and then um narrow rowed from fifty ft to thirty ft in diameter, which is still pretty substantial, and they use those to send water from the lake mead to the power station turbines on either side, the Nevada side and the Arizona side, and that's where the hydroelectric power is is generated. So they use the diversion tunnels to generate the hydroelectric power. Now, yeah, it's amazing the water falls into these things. Uh go down about five feet into this power station, which, by the way, part of the tour is you get to go down into the bowels. We miss that, which is kind of neat. Um. Yeah, you didn't about the word bowels just turned you off, So that's why did um. So it falls about five feet into the power station. Uh, it's flowing here at about two thousand cubic feet between two and three thousand cubic feet per second, And anyone who knows what hydro electric power means, all you're doing is using that water to spin turbine and connect that to a power generator and all of a sudden, Arizona, Nevada, and California are getting juice, right, which is pretty ingenious because if you think about it, when when that water is flowing from Lake me down these um these pen stocks to the turbines, they're not using any pumps or anything like that. It's all just gravity um sending it over like a six hundred feet drop and what did you say? It was like two thousand to three thousand cubic feet per second, So that chuck is a lot of water. That is a tremendous amount of water, so much so that converted into big Max per second. You're talking eighty nine thousand, three hundred and sixty seven big Max per second if you're moving water to two thousand cubic feet per second. And that's actually accurate based on the dimensions of big MACA did the calculation. That's how many big Max would be flying past you in a second if if it were big Max instead of water they were sending down there the other stat which staggers me and uh, because I was thinking, like, there's no way Julia actually figured out the horse power of this whole thing, and she did well, she found someone who did, and this thing can crank out almost three million horsepower combined. I know that's a lot of horse power, but I'm just trying to like put it in other terms, like how many how many trains is that We'll just think about standing uh, in the middle of a desert and seeing three million horses charging at you. It's a lot of horsepower. That's a lot of horses. It is so the way that the water gets from Lake Mead down to the turbines, I mean, it's all very much control. And the way they control it is if you ever go to the Hoover Dam, just on the Lake Mead side of the dam, there these four towers that rise out of the water, and those towers have gates that can be opened and closed to let water in. And those are the gates that let the water and that send it to the pen socks down in into to power the turbines and the power stations, apparently to the tune of three million horse power. It is amazing. Again, all of this if you step back and just kind of look at it as a kid, you're like, yeah, put a hole here to make the water go there, to make the turbine spin. It's really simple in a lot of ways. But the amount of ingenuousness it took to actually execute it, that's where the chef's kiss lines. All right, let's take a break here and uh, we're gonna come back and talk about uh spill ways right after this. Alright, chuck. So they used two of the four diversion tunnels to feed the turbines to generate hydroelectric power that leaves to other ones. And I know they didn't just forget about those what are they using those four? And this is sort of the final component here, because what they had to do was, Um, I mean, when this thing is working great, which it almost always has, we'll get to that in a second. Um, everything's awesome. People are getting power, people are waterskiing on Lake Mead. Um, people are getting water, Crops are getting water, cows are drinking water. Everybody's happy. But they did have to think about the fact that the Colorado River used to be quite a bear and may get angry again one day, or this thing may fail one day. So we need to think about what happens if something does go wrong, whether it's a flood or the system breaks down or something. So they thought ahead and they they set up what we're called spill ways. They can actually divert once again, all that water into those two outer tunnels, uh that are now referred to as spill ways. But this is downstream, right right, so not the upstream tunnels that are being used UH for the flibbertyg of its. Have you ever seen a fish ladder? Surely you have, Yeah, we've I think we've even talked about them on something before. Yeah. That's basically like an upstream spill way. Yeah, okay, So this is the opposite that's sending it down, and it's it's it's the exact same principle and almost the exact same design as that little overflow hole that you have in your sink. So like you you can't flood your bathroom because eventually, if that water or level hits that hole, it's just going to go into the hole and down the drain. Anyway, this is the exact same thing. So they utilize those remaining two um diversion tunnels as the spillways, and they didn't lower them at all. Remember they reduced the other ones to like thirty ft from fifty ft. These are still fifty ft spill ways lined with like three ft of concrete. But they follow very similar trajectories where you know, the water hits a certain level on like a flood or whatever, and it goes through these spill ways and then it drops several hundred feet I think six hundred feet, which is a lot for a lot of water to drop. It starts to pick up a pretty pretty high velocity, and then it it all spills out of these gates a little further downstream beyond the hydroelectric plants, and everybody's saved and happy and nothing. No, no waters ever meant to go over the top of the Hoover Dam. If that ever happened, that would be colossally bad. It's never designed to do that. Um, it probably never will do that. Even if humans suddenly just vanish overnight, the spillways would probably still work. But um, that's what it's designed for. Is designed to just get rid of that water and reroute it, basically like they rerouted the Colorado River, but this time they're rerouting it around the power stations which would be swamped with that much water. Yeah, and they don't let it's it's not like they were like, all right, if this gets within like three or four feet, we're gonna take action. If it gets to within they said it at twenty seven feet. So if the water rises for any reason to within that twenty seven feet to the top of where those cards are driving, the spillway gates open up, uh, and it diverts that water and the dam uh is not able to breach, which like you said, would be catastrophic. It let's out a big huray uh. And the good news is the system, that outlet system has never failed uh and it's only had to be used twice once for the test in one and then in nineteen eighty three. It was actually a flood that got within that caused that river to go up within twenty seven feet and they opened up that spillway, which I imagine there was I mean, it was probably kind of scary, but they were probably some engineers that were pretty excited to get to use those spillways finally, Yeah, because they I mean, you would have had to have been an old time or to have been there for the nineteen forty one test by the time three came around. So I'm sure all these people wanted to see this because they they had never seen it work before, and they also wanted to know if it did work. And it definitely worked. I mean it was it wasn't a drill like one. It was a straight up flood like this is what it was designed for, and it worked just fine. Yeah. But both times during the test and during that flood, those spill ways suffered some some damage. So let's talk about the um the failures that have happened over the years. Right. So in those those first few years, when everyone was still kind of biting their nails a little bit, there were there were a couple of problems. Um Air bubbles formed in these spill ways and seepage, like water started seeping under the base of the dam, which is not good at all. No, and those are actually two different things, so both we'll start with the the um air bubbles, right. So that's that's called cavitation. And when the spill ways were used, both in that ninety one test and in the actual flood, when that water, that huge, huge amounts of water fell, you know, six hundred feet down to the elbow of the spill way that led it the rest of the way out to the river um when it hit, when it impacted. By that time, these things called cavitations, a little like bubbles of vapor had formed in the water column. And these things were so strong that when they collapsed they had enough force that they could like shatter concrete. So when this the spill test was done, the spell way test, and then when the flood was over, and the spell ways were turned off. They went and investigated. There were huge chunks of concrete missing. The water had just sheared it away like it was nothing. And the cavitation is still not really fully understood. It's part of like a really um infrequent unusual occurrence like that, like water typically doesn't flow that fast on Earth over you know, a man made structure, so it's not like something we have to worry about. But they figured out that if you insert aer raiders or air ducts something to insert air into that water to kind of lessen the blow kind of pad or pillow the the impact of those cavitations collapsing, it can protect concrete. And so after one they didn't really know what they were doing after somebody had figured out aeration by that time, and so they installed them right afterwards. And as far as I know, they haven't tested it to see if it works, but in other places it's been shown to work, so I think gets a pretty safe bat that if those overflow spill ways have to be used again, they probably won't cavitate because of the aeration that was inserted into the spill ways. Now, yeah, well, I actually saw in forty one they knew that they could do this with air ducks, but the government wouldn't pony up for the money. Oh is there right, Yeah, they denied the funds. And uh it took until that flood of eighty three when it happened again, when the government was like, all right, we'll pay for this stuff. Fine, Hoover's ghost came out for the don't get involved. It's not the government's job to pay for broken concrete. So, um, this seepage was the other was the other sort of engineering failure, and we should, you know, we need to point out that this thing is performed really, really well, Like none of these failures broke the damn. You know, that's a really good point, and I think it's definitely worth pointing out. Like the spill waves those were huge you know where where and tear that that probably shouldn't have happened in probably won't again. But yeah, the whole system still worked. Yeah. So if you have a damn like this, Um, the stability of this whole thing relies on keeping all that water out. So any seepage under the base of that damn is not good. It's gonna cause uplift pressure that's gonna shift the whole foundation, and this grout uh basically was was failing. Um, a grout curtain is going to prevent the seepage. So they were pressure injecting all this grout into these holes trying to fill cavities, but it, uh, it was not and they were getting some seepage in there. Well, they did a really poor job of geological exploration before they ever started the project. Yeah, that was the main issue there. So, like the same grout that they they introduced into those cooling pipes after they were finished building the actual damn itself, they were they were introducing that into these holes they drilled to kind of fill those cracks, crevices, faults, all this stuff that's in the bedrock. Because normally, when the Colorado rivers flowing chuck, it's like it's fine, it's allowed to keep going and it doesn't try to get anywhere aside from the river bed. But when it runs into the dam, then it's got issues. The water wants to go somewhere, right, Yeah, that's what water does. It wants to go somewhere, So it starts to find those little cracks and crevices and faults, and when it fills up enough of them, it can actually lift up the dam, and that's what it was doing, it was lifting up the dam. So they went back and drilled more holes and added even more grout and basically created this barrier. So you've got the barrier that's the dam, and then you have the barrier that's this grout reinforced bedrock, you know, hundreds of feet down into the earth. So now the water just gives up and does what it's told. Yeah, I love that they they really went overboard there and like an additional three feet underground with this grout. But imagine being like the dam is actually lifting up, it's starting to float. That is the exact opposite of what you want to go on with your damn. Yeah, for sure, because apparently on the on the face of the damn, the um upstream face, the water pressing up against it like meat, is over a hundred miles long. It's an enormous amount of water and it's being held back by this one slab of concrete. And I guess I think Julius said it was like forty five thousand pounds per square feet of pressure pressing up against the damn at all times. So yeah, that that um that's a that's just Harry if you think about it, especially then if you start to think about the that amount of that amount of concrete like being lifted up by the water and it's just basically being moved out of the way, and they had to stop it in time. Alright, folks, we're gonna take our last break. We're gonna come back and finish up with part four, Part two of Hoover Damn right after this. All right, we're gonna bring it home here with um or or we could keep talking about it forever, uh, with a little bit on how um the Hoover Damn just really changed the United States and especially the Southwest. UM Roosevelt Franklin Roosevelt dedicated the damn on sept and man insult to injury. Former President Herbert Hoover was not even on the guests list to come from and see that dedication. No, do you mene like four years after and he was the guy who was the first champion of the whole thing too, I mean like it was his project for sure. So uh, that area, that region, it really changed everything, um aside from Boulder City becoming a real place, which is kind of neat in Vegas growing. The whole region was allowed to flourish, um because well one big reason it's because they tamed that Colorado River. No more flooding, right, Um, So no more flooding meant that you could actually have like a stable agricultural um industry, right yeah the area. It says here the region's crops and livestock account for and of the entire country's production. Yeah, and they grow so much like lettuce and cilancho and stuff that that regions now called America's salad bowl. Um. It's a huge, like, it has enormous amounts of production, and it never would have gotten to that that point had the Hoover damn not produced like a steady, reliable supply of irrigation and um done away with flooding. Like there's no more. There hasn't been a single flood from the Colorado River that's affected any of the land in the area since the Hoover Dam came online. You know, when I lived in Yuma and I waited tables at Julianna's patio cafe, there was this this dude, I can't remember his name, but this one guy that would bring in a bunch of big money guys uh to eat every now and then, like six or eight of them for these business dinners. And he was a lettuce guy. Oh yeah, okay, And I just thought it was so funny growing up in Atlanta and never you know, thought about it. But he all he did was grow let us in. If he came in with his you know, six or eight buddies, like you had to shut down and take that table only like he expected you to only wait on your table right. Well, there's some real lettuce in it for you, Oh there was. It was he a good tipper because a lot of times those guys are not well. It was he always had a party big enough to where the tip was included. Um. And he would usually give you give you a little lettuce on top of that. That's nice. Literally, here's a piece of romaine for you. It's good for you, kid, and spank you on the bottom as you were walking away down. Um. So the Hoover Dam changed everything, like Uh, places like Tucson, Arizona would not even have been allowed to happen. Uh in Las Vegas and l A booming like it did, um thanks to the Hoover Dam. Like you said, no flooding tons of production and everything is under control. One thing they did have to worry about, well, we'll talk about what they are worrying about now in a minute. But one thing they did worry about then and then, like in World War two and again at nine eleven, was the fact that it's a terror target because it so many places rely on this for water, the irrigation. That if terrorist organization took out the Hoover Dam especially I mean to be bad anytime, but especially in World War two, it would have been catastrophic. Yeah, so I guess nineteen thirty nine, the Mexican government let the American embassy in Mexico City know, hey, we just heard that the Germans are planning on bombing Hoover Dam, and UM America was like what, And they put up all these new safeguards and got military police to patrol the area. They installed floodlights on Lake Mead, they put up a steel net so you couldn't get anywhere near the um, anywhere near the dam on the Lake Mead side because remember, I mean, people are like boating and recreating on this um. So they had to kind of keep people away from the damn for the first time. And but they still kept going on. You could still go visit and everything, and then Pearl Harbor happened. Um, and they were like damns closed and they closed the damn to the public for the duration of the war, I think until like the end of ninety five they finally opened it to the public again. All because of the dirty Nazis. Yeah, man, and they um they did. The damn itself actually had its own police force. Um. The Army of course came in there to help out as well. But it was a pretty big deal because not only are you disrupting water and maybe flooding the valley, but the power supply to southern California. There was a lot of aviation manu still is a lot of aviation manufacturing in Southern California and for and I think that's what the Nazis were really after, to disrupt the power supply to the aviation industry. Yeah, because at the time America wasn't even in World War Two yet, but we were helping the British with the aviation stuff we were building. So they were trying to strike at the heart of British capabilities by blowing up the Hoover Dam. There, unexpected the Nazis want to blow up the Hoover dam and the US is like, what did we do? We're not even in this so called World war, right, Oh yeah, helping them? It's all right, I got you. We're still not going to let you do it, but now we understand. Uh. And then, of course after nine eleven it was, um, there was a lot of fear that that could be a potential and it still limbs as a potential terrorist target. Well that was one reason why they built the bridge, the bypass bridge, was They're like, you know, this is just too vulnerable letting people drive over it. And so from what I understand, either after um the German bomb plot became evident or after nine eleven, and I think it was after nine eleven until that bridge opened up, when you drove over the Hoover damn you had to wait and it would happen and I guess shifts, and you would be escorted across by the police um in groups of cars, and then you'd be you'd make your way to the other side and they'd be like keep going, don't even look back, or we'll arrest you. Um. And then that's how you got across until they finally opened the bypass, which must have been um up, but there are a lot of delays. Yeah, probably so in that situation. So the current threat, aside from that looming terror threat, is the fact that, uh, there have been about sixteen years of drought in that area, and uh it's scary. Man. Lake meat is not the same. I mean it is what it like a hundred and fifty feet uh lower than it used to be then it wasn't two thousand and thirty feet. I mean that's amaze. That's a huge, huge drop. Yeah, there's like a bathtub ring high water mark. Now it's just the discoloration along the canyon walls where you can see where it used to be, and it's really significant. And the problem is when they built the dam, they built it so that the the gates that um allow water down to the pen socks to the hydro electric plant they cut off at a certain height. After that the water is too low to flow through the gates, and in you have no hydro electric power. Same thing with the pipes that pump water out to Las Vegas and Los Angeles and Tucson and everywhere else that gets water. Um, they're at a certain height too, so once they I think, once the water level hits like eight ft, there's no more water that can be drawn out. And they actually got around this by creating a new low level pumping system to where they came in and went under the under Lake Mead and tapped into it and now just like a bathtub drain at the bottom of a bathtub, there's a pumping station so that that now they're not like, Okay, we have eight water we can't get to to drink from any longer. Now they're like, no, we can. We can get to all the water we need to for um for drinking, which is a huge relief. That's a big, big deal that they were able to do this. But at the same time, everyone's still very much aware that they're like, we still have issues, like we're losing water through evaporation and from um, you know, lower and lower snow accumulations up in the Rockies where all this water comes from in the first place. Like there's a big problem with climate change and it's having an enormous impact on Lake Mead, and because all these areas you know, depend on it for electricity and water, everybody's really freaked out right now, Yeah, so the the current proposition is the l A Department of Water and Power. Um, they have something on the table that it's basically like a loop, a cycled loop system. They said, why don't we do a return path for that water. Put a huge pump station, solar powered pump station downstream that's gonna then send water and cycle it back up to the reservoir. And not only that, I mean it's a pretty good idea. Um. Not only that, it would you could still you know, you could enable more power generation and also create a reserve of electricity for peak periods. So then all of a sudden, the Hoover Dam is like a big battery essentially run by uh, solar power, right, which sounds great. It's like, okay, yeah, why why just let all that water go when you're just generating hydroelectricity from it? You know, put it back. But all the people who depend on that water down stream say, uh, we still need that water. You can't pump it back into Lake Mead. We need that stuff like that's our water. Um. And that's part of the problem with it, Chuck, is that there's so many people who depend on this, not just from Hoover Dam, but there's like multiple damns above Hoover Dam too. So there's a lot of people drawing water for all sorts of different purposes. Um, from the Colorado River. That there's just it seems to be too many. There's just too many people. There's too many, there's too much need. And when you toss in climate change, uh and the impact that the sixteen or nineteen your drought is having, it's, um, it's it's it's a really precarious position right now that they have not figured out. Yeah, pretty scary, man, it is scary for sure. I got nothing else that is surprising because there is a lot to talk about. I've got one more thing. So you said that, um that uh FDR dedicated the place in right? Is that what I said? I believe that's what you said. Everybody, Yeah, that's what you said. So. Um. There is a sculptor named Oscar J. W. Hanton And you know the the winged Art Deco giant figures the statues that are there on site. So he created those. And did you notice the Toronto floor the apron that's in front of those statues. I don't remember. It's okay. So there are these two giant art deco statues. They look kind of like the Oscar Award, but with wings and they're seated and um. They're there to just basically commemorate this conquering of humanity over you know nature. Um. But on the round in Toronto is a star map and it shows the exact position of the stars in the sky on that day in when Hoover Dam was dedicated, So that future generations to come, even if there's like no more Americans and no one speaks English anymore, and this whole area has been abandoned, they could come back and find the Hoover Dam and the star map and calculate the exact day that it was dedicated, just based on the position of the stars and this Toronto floor and that neat. That's amazing, extra little touch there. Learn that on the self guided tour. By the way, yep, if you want to know more about the Hoover Dam, go go to the Hoover Dam. We can talk about it all day long. We could talk about it for two more episodes and it still wouldn't get across what it's like to be there. Uh. And since I said that it's time for listener mail, I'm gonna call this. Uh uh, Well, we got something wrong in deserts or Rival, which, by the way, we got a lot of kudos that that perhaps maybe our funniest episode. That was great. It was a lot of fun. Yeah, we're being silly that day. Those are always good. Hey, guys, been an ABBOD listener for years. Can't thank you enough for the countless hours of entertainment. Despite all the great topics and education, I've never been tempted to write until today. During your Desert Survival opening an immediate and hilariously enjoyable left turn tangent Chuck, you mentioned your tribute to Annie with a reference to food Glorious Food. I feel so dumb. That song is actually from Oliver, which I know. I know that everybody knows. You know that I know Annie and I know Oliver. Maybe they were friends. Could I have school, please, Daddy war books? That's it. That's the big line, um, he said. I thought you might get a kick out of how I know this to be true. When I was about eight or nine, my hometown did a community production of Oliver and I was cast. What part did you play? You may ask, Well, in the song food Glorious Food, there's a line that goes food, glorious food, peas puddings, and save lois. What next is the question, rich gentleman, habit boys indigestion. At the singing of Indigestion, my role and shining moment of the performance was to lean over while the tuba and the orchestra pit let out a deep and juicy note. Yes that's right everyone. I was in the credits as the flatulent orphan. See you get that he bends over in the tuba goes uh got it. Needless to say, guys, my life peaked early. I will always be remembered for that song. Thanks for all you do. That is Eddie in Denver, Colorado. Eddie, that was a fantastic listener mail, good one, like a award winning maybe, ye man, I mean, if you're talking tuba farts, you've got my heart. Yeah you. Eddie just got the Hoover Damn Award for listener Mails, the current Hoover Damn Award older. So thanks for that good one. If you want to get in touch with us, you can go to stuff you Should Know dot com. All of our social links are on there, or you can just send us an email. Send it off to Stuff Podcast at i heart radio dot com. Stuff you Should Know is a production of iHeart Radios How Stuff Works. For more podcasts for my heart Radio, visit the iHeart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.