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Great video as always! 100 year Rapidan Dam south of Mankato, MN had a 'failure' back in June effecting bridge footings as well as a family owned restaurant as well as the downstream impacts. If you look into it and find it worthy of a story I would enjoy your review. Thank you either way!
Rather then using the strap down sensor system; why not just paint the depth on the concrete at multiple spots and stick some cheap cameras on those spots to monitor the water depth in the control room? Seems far cheaper and less chance of problems. Besides as cheap as cameras are these days why would you not have camera eyes on the water levels at all times?
@@Morristown337Something not widley known is the reason the probes were moved was they needed to know NOT how high the water was, but how much water was in the reservoir, silt pulled up from the lower lake was filling the upper reservoir and thus they had to raise the full level in order to keep the same amount of water in the pool. The sensor wasn't really what should have stopped the pumps, it was more to tell them how much power was available, and thus it had to be moved up more and more with more silt.
Have a look at the Vajont disaster. The dam is still there, perfectly built and with no reservoir anymore. The owner knew the mountain was going to fall and was building a bypass on the mountain side, when it fell off. Entire villages where wiped off the chart. Yet, as a monument to both human ingenuity and foolishness, the dam stood and still stands.
Retired Hydroelectric Operator here. I was still working when Taum Sauk happened. It’s a familiar pattern of mismanagement, ignoring bad instrumentation/controls. We were plagued with management taking the attitude “we can probably get away with it.” At the time, there was no mystery within the trade as to what happened.
I suspect money would have been a big contributer to the decisions made. Doing things properly would have 'cost too much'. Not as much as the fines ended up costing the company in the end.
I love that you straight up perfectly explained how it happened in the first 20 seconds. None of that classic history channel 10 minute long cliffhanger bullshit “but how could this unfathomable accident occur???”
Lifelong Missouri resident, I remember this happening (though i didn't realize it's been 20 YEARS - jeez!). They were incredibly lucky that nobody was killed. Thanks for this clear and informative overview of the incident.
@@barryrahn5957 It is. This time of year is beautiful with the leaves turning color but most people like to go when it's warmer so they can enjoy the water.
I had the privilege of being part of a student geology group that was allowed to tour the area the following spring, hiking from the base to the top. It was an excellent educational opportunity, and the new rock exposures in the scour were amazing. I recall a professor sampling a freshly-exposed unit that was previously unmapped in the area, dubbing it the "purple smarty" rock due to its color and texture.
I also got to visit the exposed outcrops 5 years ago with the University of Kansas and the purple rocks (I think they're rhyolites, it's been a while) are still very much there haha I can only imagine what it was like visiting it the next spring!
I was hiking in taum sauk a few years ago. We camped on a peak and saw the dam. I was so confused of why someone had built a dam on top of a mountain. Then I looked into it and found this! Great video, as well!
I'm so very grateful to my college engineering professors who took integrity so seriously. They often tried to impress upon us how allowing seemingly small things through can turn into disasters that cost lives.
The problem is it's being taught by professors. They usually have the luxury of not being part of cost benefit. Engineers are always being coerced into complying with legal and technical hurdles in the most economic way possible.
@@xevious4142 Tbh, every (good) CS-Professor tells the students how bad it is to cut costs or take shortcuts. The problem are the companies that cut costs and then wonder why the code is low quality, hard to maintain and unstable
@@leon81061 it's a lot more institutionalized in engineering. Every engineering professor emphasized our work could kill people if we didn't do our best. CS doesn't have the same urgency unfortunately.
I grew up in this area during the time of the disaster. I heard people say “Taum Sauk” over and over again but I didn’t understand how it happened. From their stories, I always imagined a wall exploded or something. This really helped me understand the history of my old region. Thank you!
I used to hike from Taum Sauk down to Johnson Shut-Ins a lot back when I was at school in Rolla. I seem to recall that one could see the reservoir from the trail, but I could be way off-base after 20+ years.
@@Sturmcrow1 You could actually hike a relatively short distance to the reservoir from a spur from the trail. I did so several years before the disaster, not realizing the reservoir was even there. It was surreal to me to suddenly see this huge placid "lake" sitting on the peak of a "mountain" (in Missouri terms ;)). Felt like I was in some Area 51 type scenario.
All I remember about this was the MO State Parks website saying the park was closed because of a dam failure. I was planning a motorcycle trip spring 06 and I was disappointed because I wanted to camp there. There was nothing really in the news about it, so I just remember just shrugging it off and thinking "Maybe there was too much rain. Good thing the brains in charge evacuated everyone." I never had any clue until now that there was a huge hydro electric battery there, or that the people operating it just let it run over, lol. It sounds like we all got really lucky.
8:58 "They FIGURED that doubling that amount would be enough" The older I get and the more I interact with people who are supposed to be the experts or authorities in their field the more I realize that people are literally just guessing and relying on intuition when it comes to serious issues of public safety. I'm an electrical contractor and I recently found out that a professional associate who is a architectual draftsman has been using the same load calculation figures for every house he has designed for 20 years because he's "never been called on it" before. He asked me to do it for a project because the county actually called him on it and asked him to resubmit.
My mom and I camped at Johnson’s Shut-ins the summer before this occurred. I took my family there a couple years ago and seeing the drastic difference in what the park looks like is incredible. The boulders left scattered all over the old campground are absolutely massive!
My family would camp there too and I remember climbing a metal staircase on the dam wall and looking over at the full dam. We were kids so we didn't understand then but I remember that was the last year that we went camping nearby.
I was one of the reinsurance claims adjusters working on the Taum Sauk dam collapse. I was surprised the event did not make the main stream press (CBS and ABC). on the other end I legally could not talk about the event. Its amazing there was no loss of life!!!
That's the problem. Corporations issue these NON DISCLOSURE AGREEMENTS which is counter to the Constitution. There is no transparency or truth when you are allowed to keep hiding it. It is asinine.
@@OneAdam12Adam it's not "counter to the constitution". the right to free speech is SO poorly understood, and here's exhibit A. the constitution projects your right to free speech from the government, NOT private institutions. this is why speech can be moderated in places like online forums or social media sites, and they can ban things like hate speech. however, the US government is NOT allowed to do that, which is what the First Amendment actually dictates. same applies to the right to protest, the right to religious freedom, etc etc. companies are completely within their lawful and constitutional right to issue NDAs to their employees, and you can only break your NDA if you're reporting a crime. "i think they did a shoddy job", even if well substantiated, is just an opinion, it's not a crime. unless you can concretely point to criminal activity as a whistleblower, you can't just flap your mouth about company practicies no matter how scummy you personally found them to be, at least not until the NDA's termination (most NDAs have a kind of expiration date and aren't indefinite). now, having said all that, do i think it's right for companies to hide shoddy, scummy business practices behind NDAs? no, not at all. i think they frequently abuse NDAs to cover their butts. that doesn't make it unconstitutional, it just makes it scummy. it's BAD. but not illegal. (the NDAs i mean, some of the practices they hide are illegal though)
@@OneAdam12Adam kept in mind back and today I did not work or reside in the USA. Most of America's insurance companies are reinsured outside the US in countries were I live. This keeps US insurance premiums lower. along with that we are restricted from speaking about any insurance/reinsurance matters as it may prejudice the matter/very bad business practice.
My mother told me that there was a family home caught in the flood coming down the mountain. She said it was a miracle that none of them were killed, especially the small children. Apparently they were able to hold on to the kids despite the rushing torrent of water around them. I don't really know the details beyond what I was told. I'm pretty sure it's the family mentioned in the video.
Missouri tends to get ignored by the coastal press. Unless there's massive loss of life, or some other really huge disaster, they seem to think we don't exist.
i just wanted to say, as someone with auditory processing issues, and a partially deaf brother, your videos being fully captioned is amazing for us! thank you!!
I wish more channels were aware of the tool @JeffGeerling /@Level2Jeff did a video about 3 months ago . "Every RUclips Creator should have subtitles (it's easy!)" It's a simple LLM tool (Called Whisper) that can run on just about anything and currently better than the YT automated stuff by a significant margin. I really wish he had been further amplified. (There's some other tools, as well, like Davinci Resolve has something built in)
All I can say is that Ameren got very very lucky this happened in the offseason for Johnson shut ins. This could have killed 100s of people if it was in the summer because it wipped out the entire camp ground and rushed through the shut ins which is packed during the summer.
@@TheNighthawk00 it drains and refills almost everyday during the summer. It drains for power during high power need times usually in the afternoon during the heat of day and then is pumped full at night during low power need times.
@@KenHauptfleisch It was only survivable if you went up a tree I would think. The ranger and his family survived because the structure they were in absorbed the force of the impact as it was knocked off the foundation and it was lighter so it stayed on top of the water and debris.
Fascinating. As a retired Safety Engineer I'm surprised the original over topping was not a critical event requiring immediate review and corrective action. It would seem they would check to make sure everything in the reservior was still in spec with the original plans and that any changes were fixed immediately. Apparently they did not understand the failure possibilities and results. I might have to go visit this dam!! Great video!
From 12:20-12:25 he mentions that the "red flag" of the original over topping was missed because the owner hadn't notified the regulator that it had occurred. Agree that the corporate culture at the owner clearly did not include sufficient safety oriented thinking.
They did send divers, they _thought_ they identified the root cause, and they _thought_ they applied sufficient mitigation. But they didn't follow up on whether the mitigation was sufficient and whether the detected cause could explain the issue sufficiently. Especially sad was the issue of redundant overfill sensors connected in an AND configuration and set at a point too high. Those are the issues that a person stationed can see and start thinking "now why is that happening". Machines are really good at following orders, but they don't have common sense.
@@Validole its a sign that no one thought at all. As usual. On the land - because "its not my task to think, I am not paid for this", in office - because they do not know whats going on somewhere in 1000s miles, and "its not my task, I am Great Fuehrer, deciding about millions, not $100 sensors, let some stinky engineer down there thinks!". Kaboooooom.
I don't believe the public can access the site. (Maybe you have contacts?) But before the disaster, you could drive right up to it and walk to the top. You could also drive down to the power plant at the bottom of the mountain. There was a really nice little natural history museum at the gatehouse that was worth a visit, too. I sometimes wonder what happened to that.
Grady, we definitely need a video on Hurricane Helene's impact on my beautiful Appalachia and the "high speed fluvial hydromorphology" that occurred, and the near failure of the Lake Lure Dam! Some of the footage of those little streams turned into insane raging torrents is terrifying!
It’s very cool to walk through. done the hike through it a few times and it’s pretty much completely grown over now unfortunately but very cool hike after it happened.
@@Cody_michael damage is neat when it is intentional too. You can learn so much about the structure of things by watching them fall apart. scheduled demolition of towers is always fascinating to watch. We're unravelling the secrets of the universe by watching subatomic particles shatter. Automotive safety has been improved astronomically by people who are fascinated by the results of crash tests. Nothing wrong with being interested in the results of an event. There's something wrong with hoping for the event or acting to cause the event though.
I worked on the “liner project” in 2004. Let me first say, this place is incredibly HUGE!! Until you are INSIDE the reservoir when it is empty, you have no idea how big it really is!! I was part of the crew that was spraying Gunite on the inside of the reservoir to “smooth” the surface to prep it for the “liner”. Everyone of us on our crew questioned the ability of the reservoir to “hold” the water safely due to NEW levels of hydrostatic pressure because the reservoir would no longer be “leaching/leaking” due to the new liner. Seeing your explanation of what actually happened is crazy, to think a simple sensor on the TOP of the Run Off Wall could have stopped this, but I still say that the hydrostatic pressure was never properly accounted for and if it wasn’t the overflow that caused this, the pressure eventually would have. I also thought that the someone would have reached out to us, the workers, and asked US questions about what we saw when we were working there. Guess we are just the dummies that do the work, we don’t much more than that I guess. Great video, appreciate your explanation.
Stopping the leaks made no difference whatsoever to the hydrostatic pressure. HP is a function of the water level, which is controlled by the pumps. The leaks just caused the pumps to do slightly more work. Also, there was no "run off wall" because the dam was not designed for runoff. There were sensors at the top of the retaining wall, but as this vid made clear, they did not work due to the subsidence on the opposite side of the wall. The subsidence was caused by excess soil in the rock embankment - this in turn was caused by the "dummy workers" not doing what they were told by the designers when the dam was first built.
The excess soil in the rock embankment reminds me of the Kansas City Hyatt disaster. A classic case of where the construction crew didn't adhere to the engineering specs and the engineers didn't double check that their instructions were being followed. I'm an electrical engineer with over 40 years of experience and I've lost count of the number of times that corners were cut behind the engineer's backs.
@@jeromedrescher1402No, they did not. While the change was discussed between the contractor and the engineering team, it was not properly analyzed or approved by the engineer in charge, Jack D. Gillum. The lack of a detailed review of the new design led to the failure of the connections under load, causing the collapse of the walkways during a crowded event, killing 114 people and injuring many more.
@@AncientWildTV Corners were cut in the construction of the Hyatt Regency skywalks for a variety of reasons, including miscommunication, pressure to meet deadlines, cost considerations, and inadequate oversight during the construction process. 1. Simplification of the Design for Easier Construction: One of the main reasons corners were cut was the decision to modify the original skywalk design to make construction easier. The original design called for continuous support rods running through both the second- and fourth-floor walkways. To make installation simpler, the contractors changed the design to use two separate sets of rods. This change was meant to save time and reduce complexity in the construction process but led to the fatal increase in load on the upper walkway’s connections . 2. Lack of Proper Review: The modification to the rod design was not properly reviewed by the structural engineers. The engineering firm, Gillum-Colaco, was overwhelmed with other projects at the time and did not perform a thorough analysis of the changes. This inadequate review allowed the flawed design to proceed unchecked  . 3. Cost and Time Pressures: The Hyatt Regency was a high-profile project, and there were likely pressures to keep construction costs down and meet deadlines. Cutting corners by making design modifications without full review might have been seen as a way to keep the project on track. Unfortunately, these shortcuts came at the cost of safety . 4. Miscommunication and Lack of Accountability: There were several communication failures between the contractors and engineers. The engineering firm assumed that the contractor would seek approval for any significant design changes, while the contractor assumed the changes were minor enough not to require such approval. This lack of clarity in responsibilities contributed to the eventual collapse  . In summary, a combination of time-saving measures, poor communication, and insufficient engineering oversight led to the corners being cut, ultimately contributing to one of the deadliest structural failures in U.S. history.
great job on this. I worked at Johnson's Shut Ins in 2003 and 2004. We always talked about what would happen if the dam broke. So glad it was in December and not July with a full campground of up to 500 people. the Park Superintendent Jerry Toops and his family discussed it several times when I was there. It's amazing they survived the cold water after being swept away. I also still have piece of the original inner black liner material from the reservoir.
What a ridiculous engineering design. Why in the world would you put all that weak concrete wall up there on top of that Hill when all you had to do was dig down into the top of the hill and you have a pool.
@@larry77117 weak concrete? It only broke when they let it overflow and too much stress was applied on the weakest point of the tall concrete wall…. Let’s not be those idiots who start pretending it was a terrible idea to begin with because something highly preventable went wrong.
@@larry77117Let me guess, you’re not an engineer. Digging a hole is orders of magnitude more expensive than building up a retaining wall. The video goes over the economic reasons for the project in the first place, your idea would have made it a non-starter.
Howdy - I wanted to let you know, your videos, especially those on energy production and dams, inspired me to return to college this Fall. My college career so far has been pretty messy, but watching your content reminded me of how much I enjoyed my electrical engineering course in high school. I'm now attending Texas State University, hoping to one day work at a hydroelectric facility, or in other renewable energy fields. Keep up the wonderful work! I'm sure I'm not the only one to be inspired by your love for infrastructure. Thank you :)
Congrats on the decision to go back to college. Now go get yourself one of those Ground News subscriptions that Grady advertises. As a college student, you will be subjected to a lot of one-sided indoctrination. Ground News can help you find a balance of news sources. Good luck in school!
I'm not from the Ozarks but my parents lived down there for about 15 years. Every time I drive up Highway 21 north I've wondered what that thing was on top of the mountain. It never occurred to me that it was a dam but that must be it. Thanks for solving a long time mystery for me!
Even the most rainy countries in the world barely have about 3,000 millimeters of rainfall per YEAR. That's like 10 feet max. So in case the exits are clogged AND you know that a heavy rainstorm is coming, you'd only need the water level to be 10 feet below the max capacity and you'd be good for an entire year to fix the clogging even in the most rainy country in the world. And that's if we exclude the possibility of simply using emergency drainage systems like they have in dams.
Most rain falls infront off mountains, because of the fall of temperature by every meter of hight and vapor pressure. And like others already wrote: it can be calculated by weather forcast.
I was a geology student at the University of Missouri: Rolla at the time of the collapse. We spent a lot of time discussing this. Great video describing what happened.
It’s a pleasure to see this, I’m a St. Louis resident and I go to Johnson Shut-Ins state park every summer with my family. it’s a great place to swim, no trees still have not grown in the entrance center, and the water has carved a scar into the mountain that is still noticeable.
Preceded was right. (If what they were saying was that an accident is made through a series of failures) Also preceded means roughly that the thing that was just referred to happened after what is about to be referred to. IE: the famous phrase "your reputation precedes you" means that the person heard about you before they met you.
Things I love about this video: (1) the intensity with which you deliver the words "and what the investigations found would change a lot about the field of dam safety", (2) the fact that I am immediately 100% hooked and want to learn all about dam safety and how the field changed as a result of these investigations
I operate a Pumped Storage Dam and we have training about this incident! We have automated sensors AND a live camera to physically verify the Upper Reservoir level. We also have a spillway as a last resort lol
Found your channel whilst helping my kids with their science assignments. Just subscribed. Incredible research stuff you have, with very substantive background and historical details. Well done. Greetings from Port Moresby, Papua New Guinea.
I live a few miles from Tom Sauk. I have flown my airplane over it several times. The entire hillside is still completely stripped. There are huge boulders scattered in the fields below it. It's wild looking.
@luciustarquiniuspriscus1408 it's been a while since I've been that way. Looks like they have added more fill over it. The field to the west still shows boulders though.
I love this because I'm a raft guide who works on a river similar to this. Having an upper reservoir seems so unique to most people, but it seems to be the more efficient use of water if you look at energy demand and production. Thank you for such an informative video. I wish more people would see this. Some people think the river runs in a circle... I say "sometimes..."
I backpacked the Taum Sauk trail a couple years ago that runs around this, with no prior knowledge of it existing. Atop one of the adjacent peaks you get a great view, but man was it quite the sight to come upon... Almost gave you an uneasy feeling, but no doubt an engineering achievement.
@@michaelthomas7999yup same, like what the hell is that ? Then we did the Tom Sauk section and were like why do they have signs saying if you hear an alarm run straight uphill. My buddy sent this and now we know.
Hey Grady, I live in Asheville. Over the past couple of weeks, I've seen water completely destroy our infrastructure and watched crews scramble to repair it. It would be cool to see a video about how large amounts of water can overwhelm and damage things such as underground pipes and utilities, roadways and water treatment plants and how it can be prevented.
I bought a project truck in the area about 10 months ago. On my way home is when I first noticed the structure. I had no idea what it was, but it looked absolutely magnificent and monstrous. I had to find a spot to pull over and look on satellite imagery to find out what it was and was totally amazed! I had no idea such a reservoir existed. This is the first time even hearing about the failure. Thanks for the info!
I had to go to college to learn about engineering disasters. That was back in the 90s. I visited Johnson Shut Ins as a child and coincidentally I was there just a few years ago. I never knew about this catastrophe until I watched this video. There's a lot of value here.
I'm glad I'm not the only one there that really should have known about this when it happened. It's amazing how it really didn't get any press to speak of.
As a nearly 30 elementary music teacher I find listening to stories like this astonishing! My mind is blown by the capacity of innovation humans can design. I know this was a failed “project” but it’s like many things in my mind that seem inconceivably impressive. Thank you for sharing these types of videos and stating them in a manner that “simpler” minds can understand!
Grady.... I'm in my late 60's; but I want to share something - admittedly "..again" - but it certainly bears repeating: "The WORLD ought to see your videos".. I sincerely believe that. To that end, I have purchased your book, etc ... all in the service of doing what I can to further your channel. Just not enough words to express how highly I think of your efforts.
I live about 85 miles north of Taum Sauk. I remeber the failure. I have not seen a better explanation of the event. Well done. The camping at Johnson Shut-ins and water activities are great. The failure did a lot of damage, but the restorations to the park went well.
Visited it as a kid in the 70's. Shame it did damage to Johnson Shutins which was an awesome state park in that era. Seems like it was poorly designed from the start. Add poor maintenance and you have a recipe for disaster.
@@martincox9691 l do not know. I remember the natural waterslide of the shutins and diving off of the cliffs around the corner from the shutins. I jumped from about thirty feet but people were jumping from what looked like 60 feet. I was so taken with the river that l recall nothing about the campground except we camped in it.
@@othgmark1 That entire area was pretty much destroyed, while it's still there, it's not the same at all and the water isn't deep enough in the area to cliff dive anymore.
Love seeing you cover something that is so local and personal to me and my family! I was only a child when the disaster happened, but it affected everyone that loves the ozarks, and especially Johnson Shut-ins State Park.
I've started working on Energy Security in Britain very recently and your videos have been very insightful in getting some basic understanding over the technicalities of such projects and the challenges they may face. Really appreciate the knowledge you share with us!
My family and I camped at the Shut-Ins yearly until this happened. We now stay nearby but still go every year. This is one video you don't see in the Visitor Center. I am thankful this happened in the off season and that the Ranger/Administrator and their family were they only ones impacted and no lives were lost.
Being involved in a rural water system with a reservoir, I've seen the filling telemetry fail many times and an operator is not always present. While there is an overtopping mechanism, I'm not really sure the hillside below could withstand sustained flow. I think I'll open this question again. Thanks!
Excellent video. Great production quality, professionally presented. No self-serving, talking head promotional pitch at the beginning. Thank you! As a retired engineering from the nuclear power industry, I was aware of pumped storage for Nuclear plant but not for coal fired power production. Very interesting.
I was about to say "Sounds like a Normal Accidents scenario", then Grady chimes in! Excellent book, definitely a must read for anyone who wants to study failures in any system, especially complex ones
@@andrewjames4786 The "Swiss Cheese Model" seems more on point: a bunch of (relatively) minor errors and failures that, combined in just the right way under just the right set of (normal) circumstances, permits the entire system to fail. You do wonder how anybody could see water over-topping the dam, without running with hair on fire to the engineer in charge. While it's true that it has to over-top _somewhere_ along the upper edge, not being curious enough to discover that the dry side is a full two feet higher indicates a "tell the boss and let him worry about it" mentality. (The boss failing to actually worry about it is the most egregious of the many errors.)
what in god damns name makes this a Normal Accidents scenario. This was complete incompetence at every "minor" issue. ONE TEST would have showed the redundant systems did not work. If this is considered a Normal Accidents scenario then we are forgiving the idiots that made those errors has if it was easy to make. You have to be completely brain-dead to implement these systems and not do it right or just test the thing.
@@jpdemer5 Disagree, the Swiss cheese model is about failures in mutually compensating *safety* systems, while this is a failure of holistic design because of the iterations and poor initial conditions.
A true understatement, I think most people watching this have no idea how bad that would have been. The main attraction of the park is basically a meat grinder, the lucky ones would be swept away
The acute geological change of the park makes Taum Sauk especially fascinating. Look at the boulder field! Side note: deregulation is the precursor to catastrophe at a comical rate. The public neither knows about nor has an avenue to effectively express concern over how a company is operating. That's why you get "whistleblowers" instead of transparency into what's happening.
Wow, I use to camp at that beautiful state park and its river in the 90's and remember being disturbed that we couldn't go any longer due to this incident. Being a kid at the time, I never really grasped what had happened and never saw any photos of the area. Thanks for this deep dive into a disaster? and its aftermath.
I remember when this happened. We used to live close to Johnson's Shut-ins Park and went there a few times before the dam failure. I haven't been back since the disaster. Good reminder that I need to revisit.
1. put in level sensors in without measuring elevation! 2. no spillway 3. filling to tippy top 4. Lack of time sensitive shut off. "Hey why are the pumps running an extra 30 minutes today?" All equals = Total gross negligence. This project is not sound engineering at all, sounds like a bunch of sloppiness disguised as engineering.
I work at Mt St Helens. We have 4 earthen dams up here. 3 created by the eruption and landslide, and one man made to hold back sediment. An early retention dam failed in the 80’s. The army corps of engineers constructed spillways on 2 of the natural dams, and Spirit Lake, the most well known one, had a tunnel constructed to act much like the hole in a bathtub. To this day the tunnel has issues (turns out in a. Volcanic landscape, there are faults… and the retention dam had to be built bigger recently. Nearly 45 years later and still dealing with it!
I love learning more about Taum Sauk. My dad was a dam safety inspector for the State of Missouri - he was one of the first engineers on the scene. This completely avoidable (and totally foreshadowed) nightmare scenario could have been worse .. it could have been a summer holiday weekend.
Another excellent video by Grady. I have just one nit: At time 3:50, he says, "... but, there are no valleys at the tops of mountains". The Bath County pumped storage project took advantage of a valley at the top of a mountain for its upper reservoir. 🙂
There are plenty of pump storage facilities in the alps which span heights of more than 1.000m. Like Lac des Dix. But even if you could say they are on top of a mountain, they are still valleys, but quite far up a mountain.
I go to Missouri S&T, a state school with a massive engineering program. In our library, I found a massive thesis about this. The author wrote that she was halfway through another one when she decided to write this one because it seemed like such a horrible, crazy eventuality, but it needed to be studied and prevented from ever happening again.
I go to Johnsons Shut-Ins with my kids all the time, and have hiked that scour. I have been waiting for someone to make a good video on what happened there in 2005, thank you Grady!
You ought to cover Ellicott City, Maryland and how they've coped in the aftermath of back-to-back "historic" floods. I had friends watch their cars float away on the torrent from the second story of a bar they couldn't leave due to the floodwaters. An enormous mitigation project is in the works to try to "floodproof" the historic downtown. One issue that's been brought up is now rampant development on the hills above the town has decreased the amount of land available to absorb rainfall, leading to streets becoming waterfalls and rivers in heavy rains.
Grady, I love your videos! They are excellent for me to play while I'm working. I'm in a crane for 10 hours a day, and your videos are pleasant to listen to a glance at for at least an hour daily. Keep up the great work! 😊
Grady, here in Chattanooga, we have one of the only pump storage facilities that are both on top of the mountain AND mostly a “natural” reservoir. Raccoon Mountain Pump Storage operated by the TVA utilized a retired quarry in addition to a wall created to close up the U-shaped reservoir. Check it out!
I was just scanning the comments to see of anyone would bring up Raccoon Mountain. Thanks for doing that. I'd never heard of pump storage before until years ago, when visiting Chattanooga with a friend, he said, "have you ever seen the Raccoon Mountain Pump Storage facility." It blew my mind at the time that power could be stored in this way but it also made such incredibly practical sense.
Thanks again Grady. I like the way that you are matter of fact about the dreadful human foibles that create such disaster...never preaching, just explaining. No rants, just calm relating of facts.
As someone that spent a few years inspecting foundations and designing upgrades, mostly related to fixing settlement, I saw a lot of undermined foundations and footings. EDIT: It's always due to water as well. During a large rain storm see where all the water is running off your roof, or your concrete patio, etc, and make sure it isn't going by your house or garage or anything supporting a lot of weight.
@@hughoxford8735 makes sense. For some reason I always conceptualized the "mining" part of it as a much bigger sort of...well, mine-sized hole! Always seemed like a horribly inconvenient way to try to get at somebody, but your explanation makes more sense 😝
Good one, Grady. Thanks. Major control system failure but right before you said "spillway" I was thinking they should have had a smallish one that would dump into the lower reservoir with sensors (or camera) in that to detect spillage. Like so many of these types of failures, it's usually a chain of events to blame that are perfectly visible in hindsight.
Interesting. Near my hometown in Germany lies a similiar facility, the "Pumpspeicherkraftwerk Geesthacht" which is around half the size (3.8m m³) of the Taum Sauk facility and was built in 1958. Glad to report there have never been any issues with it (other then complaints of environmentalists about fish getting sucked up in the pumps).
This is going to be a good one! Johnson Shut-In's is a state and national treasure! It's a shame what happened, however I think the state made some upgrades to the camp sites after the power company settlement. They now have cabins, which I don't recall any being there when I was there as a kid. Anyway, there was a lot of arrogance on the part of the power company on the original dam. That being said, we need more pumped hydro in this country, and I hope this is a learning lesson.
@@benoithudson7235 Batteries work fine but they don't have the capacity like pumped hydro. The main drawback to pumped hydro is the amount of head pressure needed in order for it to work. Usually cities don't have the amount of fall needed in order to make it effective.
@@adammuncy8475 : A single battery cell has a lot more storage capacity than a raindrop. Doesn't matter, because the grid doesn't rely on a single one of either, it relies on huge numbers. Utilities and related companies have clearly decided that batteries is where it's at, because over the past few years, they dramatically increased the amount of storage they're buying and it's almost all batteries.
17:49 - "There's no such thing as a purely natural disaster when it comes to flooding"...very interesting. Never really thought about it. Wish you would have elaborated on that some.
That also gave me a little pause, like... really? But yeah, all rivers have flood plains, that's just the natural coarse of the river. We build on those flood plains and try and control flood water, but that is a purely human endeavor. Similar concept for tides and storm surges, we choose to build there, the water is just doing what it always was. I would argue, tho, that now with climate change and larger and more frequent hurricanes, some places that might otherwise have rarely or never seen a storm surge, will now be destroyed, so in that respect, that is human-caused flooding.
Humans shaping the land or choosing where to build infrastructure comes into play. Though there are times flooding destroys only wildlife, some may still find human components.
Hi, I love your videos and enthusiasm. I'm a software engineer, I have no knowledge at all about engineering but software. I love how you explain things, which makes me interested in knowing more. Curiosity is contagious.
I really enjoy watching your videos about engineering and even though I'm not an engineer at all I still like listening about places like the Taum Sauk Dam in the Ozarks and it's eventual failure have a great week and thank you.👋☕🖖🇺🇲
When I was a kid in Boy Scouts we would camp in the group camping area at the far northeast side of the old campground setup along the creek… it would have been a deal if we were there when the water came.
This was well done , like many others, this was the first I’d heard of this project , it’s failure and consequent rebuilding, let’s hope they’ve got it right this time! All the best Jules 👍
Only if the operator checked the monitor. Being human he probably would not have done so after the first month or so on the job. It still needed a spillway, and a very simple safety cutout.
On a chemical plant I worked on we had a tank overflow. It had a high alarm but the operator missed the alarm, didn’t switch off the inlet pump and the tank overflowed. So a pump cut out was added if the level exceeded the alarm by a few percent. Sometime later there was another overflow. Turns out the operators had started relying on the pump auto cut off to do the job, ignoring the alarm and not intervening manually. Wish I could remember the next step (was probably 30 years ago!). The moral is if you going to add auto cutoffs you’d better make sure of its reliability and its demand rate and design the cutoff system appropriately with the required reliability.
I was going to suggest overflow sensors, but it sounds like they thought of those. *sigh* A failsafe feature doesn't matter if it doesn't stop a disaster when the anticipated failures occur.
There's no replacement for a nice, big E-STOP button ... also, paying attention to what's going on! Trusting PLCs to run your gear for you is fine ... only if you're aware of and *ready for* the consequences when they fail.
This wouldn't have happened if they hadn't been so cheap. If they had installed a water level sensor every so often around the entire reservoir the settling wouldn't have mattered, the pumps would've shut off properly, and it wouldn't have overtopped. If your interval is every 100', even if one or 2 neighboring sensors fail you should still have plenty of them working to avoid overtopping.
@BobBobson failure mode cound be at the plc not the sensor. Mechanical fail safe seems safer, spill way for not if but when. Also the settling of the wall, 2 feet, wasn't detected by those sensors.
@@BobBobson Grady is on the money that this was a Normal failure. Anyone looking at the design and management would predict there could easily be a failure, just like how if you look at the reporting on Boeing management it's no surprise their planes are breaking.
@@noinfo5630 As Grady pointed out, observation during the last few minutes of expected fill capacity is a pretty small labor input, especially in light of the consequences of failure. Someone made a decision NOT to pay for a worker to do that and - to no engineer's surprise - it came with consequences ... just like NOT hiring an outside process automation expert to review the PLC/sensor configuration for potential SPOF or other errors.
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Great video as always!
100 year Rapidan Dam south of Mankato, MN had a 'failure' back in June effecting bridge footings as well as a family owned restaurant as well as the downstream impacts.
If you look into it and find it worthy of a story I would enjoy your review.
Thank you either way!
Rather then using the strap down sensor system; why not just paint the depth on the concrete at multiple spots and stick some cheap cameras on those spots to monitor the water depth in the control room? Seems far cheaper and less chance of problems. Besides as cheap as cameras are these days why would you not have camera eyes on the water levels at all times?
@@Morristown337Something not widley known is the reason the probes were moved was they needed to know NOT how high the water was, but how much water was in the reservoir, silt pulled up from the lower lake was filling the upper reservoir and thus they had to raise the full level in order to keep the same amount of water in the pool. The sensor wasn't really what should have stopped the pumps, it was more to tell them how much power was available, and thus it had to be moved up more and more with more silt.
I thought I read "Hawk Tuah" in the title 😂😂😂
Have a look at the Vajont disaster. The dam is still there, perfectly built and with no reservoir anymore. The owner knew the mountain was going to fall and was building a bypass on the mountain side, when it fell off. Entire villages where wiped off the chart. Yet, as a monument to both human ingenuity and foolishness, the dam stood and still stands.
Retired Hydroelectric Operator here. I was still working when Taum Sauk happened. It’s a familiar pattern of mismanagement, ignoring bad instrumentation/controls. We were plagued with management taking the attitude “we can probably get away with it.” At the time, there was no mystery within the trade as to what happened.
I suspect money would have been a big contributer to the decisions made. Doing things properly would have 'cost too much'. Not as much as the fines ended up costing the company in the end.
62 year Hydro boy here, when we heard about it we said - it's going to be a very rainy day at the bottom of that hill.
@@MrNeocortex what does money have to do with a pump shutoff? This was pure negligence.
So many disasters have happened because "we got away with it last time...".
@@empowl1607 - okay, that was funny!
I love that you straight up perfectly explained how it happened in the first 20 seconds. None of that classic history channel 10 minute long cliffhanger bullshit “but how could this unfathomable accident occur???”
Lack of accountability has predictable results…just give it long enough.
@@frankw2900 I believe the comment was about the video's narrative structure, not the actual incident that is being discussed.
On the next episode of the mystery of Oak Island
Make sure you watch till the end to see the EXCITING CONCLUSION!
@@TheAdmiralFilmsthat show is cancer
Lifelong Missouri resident, I remember this happening (though i didn't realize it's been 20 YEARS - jeez!). They were incredibly lucky that nobody was killed. Thanks for this clear and informative overview of the incident.
I never heard of this event, but it was well explained.
Ruined the shut-ins…not the same anymore.
@@bkit50they are not. I grew up in the area, was working EMS that day. The park isn’t what it used to be
Live like 10 miles from there
Hello my fellow Missourians
Great video. I worked there for two years restoring the state park after the event. It’s interesting seeing a video explaining what actually happened.
good job on keeping the pump not turning off lols
@@SYOTOSVLOG Reading comprehension: Get some.
I've heard of Johnson's shut in state park. It looks gorgeous. I'll have go there soon.
Are you saying it wasn't common knowledge in the area what actually happened?
@@barryrahn5957 It is. This time of year is beautiful with the leaves turning color but most people like to go when it's warmer so they can enjoy the water.
I had the privilege of being part of a student geology group that was allowed to tour the area the following spring, hiking from the base to the top. It was an excellent educational opportunity, and the new rock exposures in the scour were amazing. I recall a professor sampling a freshly-exposed unit that was previously unmapped in the area, dubbing it the "purple smarty" rock due to its color and texture.
You must have had the chance to learn abt the geological processes that led to the formation of that rock right?
I have no memory of the events before but there was a big bang ;) @@AncientWildTV
@geotubedude you hiring recent geology and climatology grads wherever you are working? Asking for a me
I bet you were a Rolla “Miners” student
I also got to visit the exposed outcrops 5 years ago with the University of Kansas and the purple rocks (I think they're rhyolites, it's been a while) are still very much there haha I can only imagine what it was like visiting it the next spring!
I was hiking in taum sauk a few years ago. We camped on a peak and saw the dam. I was so confused of why someone had built a dam on top of a mountain. Then I looked into it and found this!
Great video, as well!
It's starting to sound like these engineers aren't so smart after all
I'm so very grateful to my college engineering professors who took integrity so seriously. They often tried to impress upon us how allowing seemingly small things through can turn into disasters that cost lives.
That is great to hear. Unfortunetly I don't believe these lessons are being consistently taught these days.
The problem is it's being taught by professors. They usually have the luxury of not being part of cost benefit. Engineers are always being coerced into complying with legal and technical hurdles in the most economic way possible.
I wish computer science had that same integrity but having experienced both, engineering was way more up front about it.
@@xevious4142 Tbh, every (good) CS-Professor tells the students how bad it is to cut costs or take shortcuts. The problem are the companies that cut costs and then wonder why the code is low quality, hard to maintain and unstable
@@leon81061 it's a lot more institutionalized in engineering. Every engineering professor emphasized our work could kill people if we didn't do our best. CS doesn't have the same urgency unfortunately.
I grew up in this area during the time of the disaster. I heard people say “Taum Sauk” over and over again but I didn’t understand how it happened. From their stories, I always imagined a wall exploded or something. This really helped me understand the history of my old region. Thank you!
I used to hike from Taum Sauk down to Johnson Shut-Ins a lot back when I was at school in Rolla. I seem to recall that one could see the reservoir from the trail, but I could be way off-base after 20+ years.
@@Sturmcrow1 You could actually hike a relatively short distance to the reservoir from a spur from the trail. I did so several years before the disaster, not realizing the reservoir was even there. It was surreal to me to suddenly see this huge placid "lake" sitting on the peak of a "mountain" (in Missouri terms ;)). Felt like I was in some Area 51 type scenario.
Haum Tuak
Hauk Tuak
All I remember about this was the MO State Parks website saying the park was closed because of a dam failure. I was planning a motorcycle trip spring 06 and I was disappointed because I wanted to camp there. There was nothing really in the news about it, so I just remember just shrugging it off and thinking "Maybe there was too much rain. Good thing the brains in charge evacuated everyone." I never had any clue until now that there was a huge hydro electric battery there, or that the people operating it just let it run over, lol. It sounds like we all got really lucky.
8:58 "They FIGURED that doubling that amount would be enough" The older I get and the more I interact with people who are supposed to be the experts or authorities in their field the more I realize that people are literally just guessing and relying on intuition when it comes to serious issues of public safety. I'm an electrical contractor and I recently found out that a professional associate who is a architectual draftsman has been using the same load calculation figures for every house he has designed for 20 years because he's "never been called on it" before. He asked me to do it for a project because the county actually called him on it and asked him to resubmit.
My mom and I camped at Johnson’s Shut-ins the summer before this occurred. I took my family there a couple years ago and seeing the drastic difference in what the park looks like is incredible. The boulders left scattered all over the old campground are absolutely massive!
Don’t translate...😠
भवतः हृदयस्य धड़कनं कतिपयेषु घण्टेषु स्थगयिष्यति, अस्य शापस्य मुक्तिं प्राप्तुं एकमात्रं मार्गं मम चैनलस्य सदस्यतां कुर्वन्तु….. .e@mtp
My family would camp there too and I remember climbing a metal staircase on the dam wall and looking over at the full dam. We were kids so we didn't understand then but I remember that was the last year that we went camping nearby.
We go there often. Couldn't imagine if this would have happened with the park full. Scary.
I was one of the reinsurance claims adjusters working on the Taum Sauk dam collapse. I was surprised the event did not make the main stream press (CBS and ABC). on the other end I legally could not talk about the event. Its amazing there was no loss of life!!!
That's the problem. Corporations issue these NON DISCLOSURE AGREEMENTS which is counter to the Constitution. There is no transparency or truth when you are allowed to keep hiding it. It is asinine.
@@OneAdam12Adam it's not "counter to the constitution". the right to free speech is SO poorly understood, and here's exhibit A. the constitution projects your right to free speech from the government, NOT private institutions. this is why speech can be moderated in places like online forums or social media sites, and they can ban things like hate speech. however, the US government is NOT allowed to do that, which is what the First Amendment actually dictates. same applies to the right to protest, the right to religious freedom, etc etc.
companies are completely within their lawful and constitutional right to issue NDAs to their employees, and you can only break your NDA if you're reporting a crime. "i think they did a shoddy job", even if well substantiated, is just an opinion, it's not a crime. unless you can concretely point to criminal activity as a whistleblower, you can't just flap your mouth about company practicies no matter how scummy you personally found them to be, at least not until the NDA's termination (most NDAs have a kind of expiration date and aren't indefinite).
now, having said all that, do i think it's right for companies to hide shoddy, scummy business practices behind NDAs? no, not at all. i think they frequently abuse NDAs to cover their butts. that doesn't make it unconstitutional, it just makes it scummy. it's BAD. but not illegal. (the NDAs i mean, some of the practices they hide are illegal though)
@@OneAdam12Adam kept in mind back and today I did not work or reside in the USA. Most of America's insurance companies are reinsured outside the US in countries were I live. This keeps US insurance premiums lower. along with that we are restricted from speaking about any insurance/reinsurance matters as it may prejudice the matter/very bad business practice.
My mother told me that there was a family home caught in the flood coming down the mountain. She said it was a miracle that none of them were killed, especially the small children. Apparently they were able to hold on to the kids despite the rushing torrent of water around them. I don't really know the details beyond what I was told. I'm pretty sure it's the family mentioned in the video.
Missouri tends to get ignored by the coastal press. Unless there's massive loss of life, or some other really huge disaster, they seem to think we don't exist.
i just wanted to say, as someone with auditory processing issues, and a partially deaf brother, your videos being fully captioned is amazing for us! thank you!!
Ditto for having an auditory processing disorder and I love CC...
100% deaf over here. I consider RUclips videos that don't have captions to be incomplete
I wish more channels were aware of the tool @JeffGeerling /@Level2Jeff did a video about 3 months ago .
"Every RUclips Creator should have subtitles (it's easy!)"
It's a simple LLM tool (Called Whisper) that can run on just about anything and currently better than the YT automated stuff by a significant margin.
I really wish he had been further amplified. (There's some other tools, as well, like Davinci Resolve has something built in)
All I can say is that Ameren got very very lucky this happened in the offseason for Johnson shut ins. This could have killed 100s of people if it was in the summer because it wipped out the entire camp ground and rushed through the shut ins which is packed during the summer.
Nvm I was completely wrong
@@TheNighthawk00 it drains and refills almost everyday during the summer. It drains for power during high power need times usually in the afternoon during the heat of day and then is pumped full at night during low power need times.
@TheNighthawk00 Tell me you didn’t watch the video without telling me you didn’t watch the video…
@@irocz11can imagine how long full recovery would take, they'd be finding body parts for years in that blender
@@KenHauptfleisch It was only survivable if you went up a tree I would think. The ranger and his family survived because the structure they were in absorbed the force of the impact as it was knocked off the foundation and it was lighter so it stayed on top of the water and debris.
Fascinating. As a retired Safety Engineer I'm surprised the original over topping was not a critical event requiring immediate review and corrective action. It would seem they would check to make sure everything in the reservior was still in spec with the original plans and that any changes were fixed immediately. Apparently they did not understand the failure possibilities and results. I might have to go visit this dam!! Great video!
From 12:20-12:25 he mentions that the "red flag" of the original over topping was missed because the owner hadn't notified the regulator that it had occurred. Agree that the corporate culture at the owner clearly did not include sufficient safety oriented thinking.
They did send divers, they _thought_ they identified the root cause, and they _thought_ they applied sufficient mitigation. But they didn't follow up on whether the mitigation was sufficient and whether the detected cause could explain the issue sufficiently.
Especially sad was the issue of redundant overfill sensors connected in an AND configuration and set at a point too high. Those are the issues that a person stationed can see and start thinking "now why is that happening". Machines are really good at following orders, but they don't have common sense.
@@Validole its a sign that no one thought at all. As usual. On the land - because "its not my task to think, I am not paid for this", in office - because they do not know whats going on somewhere in 1000s miles, and "its not my task, I am Great Fuehrer, deciding about millions, not $100 sensors, let some stinky engineer down there thinks!". Kaboooooom.
I don't believe the public can access the site. (Maybe you have contacts?) But before the disaster, you could drive right up to it and walk to the top. You could also drive down to the power plant at the bottom of the mountain. There was a really nice little natural history museum at the gatehouse that was worth a visit, too. I sometimes wonder what happened to that.
I was going to say they didn't notify any authorities on the issue.
Grady, we definitely need a video on Hurricane Helene's impact on my beautiful Appalachia and the "high speed fluvial hydromorphology" that occurred, and the near failure of the Lake Lure Dam!
Some of the footage of those little streams turned into insane raging torrents is terrifying!
I'm sure it is weighing heavily on his mind. Hard subject to tackle while bodies are still being recovered.
It was from all the water in the hurricane.
@@tipfertool5457 Not to mention right wingers hampering relief efforts.
Watch them blame the whole storm on the left🙄
Geo models has these up already
Thanks for the shot of the dam with the truck up top. Really helps get the ridiculous scale we're looking at.
Hi. Dad, are you out there? Dad, won't you come and play? Dad, do you not care? Is there nothing that you want to say?
regardless of the damage, it's neat to see the side of a mountain after a powerwash.
@@TheSprockee There's still so much mud on it, do you think it needs another rinse?
It’s very cool to walk through. done the hike through it a few times and it’s pretty much completely grown over now unfortunately but very cool hike after it happened.
You can blame aliens then..... 😅
Yeah Damage is neat when not intentional. Tell me more satan 😂
@@Cody_michael damage is neat when it is intentional too. You can learn so much about the structure of things by watching them fall apart. scheduled demolition of towers is always fascinating to watch. We're unravelling the secrets of the universe by watching subatomic particles shatter. Automotive safety has been improved astronomically by people who are fascinated by the results of crash tests.
Nothing wrong with being interested in the results of an event. There's something wrong with hoping for the event or acting to cause the event though.
I worked on the “liner project” in 2004. Let me first say, this place is incredibly HUGE!! Until you are INSIDE the reservoir when it is empty, you have no idea how big it really is!! I was part of the crew that was spraying Gunite on the inside of the reservoir to “smooth” the surface to prep it for the “liner”. Everyone of us on our crew questioned the ability of the reservoir to “hold” the water safely due to NEW levels of hydrostatic pressure because the reservoir would no longer be “leaching/leaking” due to the new liner. Seeing your explanation of what actually happened is crazy, to think a simple sensor on the TOP of the Run Off Wall could have stopped this, but I still say that the hydrostatic pressure was never properly accounted for and if it wasn’t the overflow that caused this, the pressure eventually would have. I also thought that the someone would have reached out to us, the workers, and asked US questions about what we saw when we were working there. Guess we are just the dummies that do the work, we don’t much more than that I guess. Great video, appreciate your explanation.
Stopping the leaks made no difference whatsoever to the hydrostatic pressure. HP is a function of the water level, which is controlled by the pumps. The leaks just caused the pumps to do slightly more work.
Also, there was no "run off wall" because the dam was not designed for runoff. There were sensors at the top of the retaining wall, but as this vid made clear, they did not work due to the subsidence on the opposite side of the wall. The subsidence was caused by excess soil in the rock embankment - this in turn was caused by the "dummy workers" not doing what they were told by the designers when the dam was first built.
The excess soil in the rock embankment reminds me of the Kansas City Hyatt disaster. A classic case of where the construction crew didn't adhere to the engineering specs and the engineers didn't double check that their instructions were being followed. I'm an electrical engineer with over 40 years of experience and I've lost count of the number of times that corners were cut behind the engineer's backs.
off topic but can you tell why they often cut corners in construction?
IIRC the construction team got engineering approval for the changes at Hyatt 😮
@@jeromedrescher1402No, they did not. While the change was discussed between the contractor and the engineering team, it was not properly analyzed or approved by the engineer in charge, Jack D. Gillum. The lack of a detailed review of the new design led to the failure of the connections under load, causing the collapse of the walkways during a crowded event, killing 114 people and injuring many more.
@@AncientWildTV Corners were cut in the construction of the Hyatt Regency skywalks for a variety of reasons, including miscommunication, pressure to meet deadlines, cost considerations, and inadequate oversight during the construction process.
1. Simplification of the Design for Easier Construction: One of the main reasons corners were cut was the decision to modify the original skywalk design to make construction easier. The original design called for continuous support rods running through both the second- and fourth-floor walkways. To make installation simpler, the contractors changed the design to use two separate sets of rods. This change was meant to save time and reduce complexity in the construction process but led to the fatal increase in load on the upper walkway’s connections .
2. Lack of Proper Review: The modification to the rod design was not properly reviewed by the structural engineers. The engineering firm, Gillum-Colaco, was overwhelmed with other projects at the time and did not perform a thorough analysis of the changes. This inadequate review allowed the flawed design to proceed unchecked  .
3. Cost and Time Pressures: The Hyatt Regency was a high-profile project, and there were likely pressures to keep construction costs down and meet deadlines. Cutting corners by making design modifications without full review might have been seen as a way to keep the project on track. Unfortunately, these shortcuts came at the cost of safety .
4. Miscommunication and Lack of Accountability: There were several communication failures between the contractors and engineers. The engineering firm assumed that the contractor would seek approval for any significant design changes, while the contractor assumed the changes were minor enough not to require such approval. This lack of clarity in responsibilities contributed to the eventual collapse  .
In summary, a combination of time-saving measures, poor communication, and insufficient engineering oversight led to the corners being cut, ultimately contributing to one of the deadliest structural failures in U.S. history.
Same thing happened with the Oroville Spillway failure. The spillway wasn't built on sound rock.
great job on this. I worked at Johnson's Shut Ins in 2003 and 2004. We always talked about what would happen if the dam broke. So glad it was in December and not July with a full campground of up to 500 people. the Park Superintendent Jerry Toops and his family discussed it several times when I was there. It's amazing they survived the cold water after being swept away. I also still have piece of the original inner black liner material from the reservoir.
What a ridiculous engineering design. Why in the world would you put all that weak concrete wall up there on top of that Hill when all you had to do was dig down into the top of the hill and you have a pool.
@@larry77117 weak concrete? It only broke when they let it overflow and too much stress was applied on the weakest point of the tall concrete wall…. Let’s not be those idiots who start pretending it was a terrible idea to begin with because something highly preventable went wrong.
@@larry77117Let me guess, you’re not an engineer. Digging a hole is orders of magnitude more expensive than building up a retaining wall. The video goes over the economic reasons for the project in the first place, your idea would have made it a non-starter.
As a Civil Engineering major, this is an excellent explanation of the various forces that affected this situation.
Howdy - I wanted to let you know, your videos, especially those on energy production and dams, inspired me to return to college this Fall. My college career so far has been pretty messy, but watching your content reminded me of how much I enjoyed my electrical engineering course in high school. I'm now attending Texas State University, hoping to one day work at a hydroelectric facility, or in other renewable energy fields.
Keep up the wonderful work! I'm sure I'm not the only one to be inspired by your love for infrastructure. Thank you :)
Best of luck, get that degree!
I always wanted to work the control panel spinning up some big turbines and switching it live into the grid after synching.
Congrats on the decision to go back to college. Now go get yourself one of those Ground News subscriptions that Grady advertises. As a college student, you will be subjected to a lot of one-sided indoctrination. Ground News can help you find a balance of news sources. Good luck in school!
@@rtqii Something as critical as that will never be left to a meat computer.
Me, but with civil engineering. This guy really is an inspiration to stay in school
This is why they have those overflows holes in bathroom sinks.
They could have grab the "depth meter" from a toilet instead of that nonsense sensor system as well.
How do you explain the glory hole in the stall
@@jjlpinct Where else would you get your sushi?
@@brothertaddeus C'mon, we know those holes are for men to share hotdogs away from their wives.
It also helps with drainage as it allows air to enter ;)
I'm not from the Ozarks but my parents lived down there for about 15 years. Every time I drive up Highway 21 north I've wondered what that thing was on top of the mountain. It never occurred to me that it was a dam but that must be it. Thanks for solving a long time mystery for me!
You telling me there wasn't an overflow spillway? What if the exits are clogged and it rains a lot? This is obvious stuff.
It is just crazy...
And this is not the being smart after the fact.
Even the most rainy countries in the world barely have about 3,000 millimeters of rainfall per YEAR. That's like 10 feet max.
So in case the exits are clogged AND you know that a heavy rainstorm is coming, you'd only need the water level to be 10 feet below the max capacity and you'd be good for an entire year to fix the clogging even in the most rainy country in the world. And that's if we exclude the possibility of simply using emergency drainage systems like they have in dams.
Most rain falls infront off mountains, because of the fall of temperature by every meter of hight and vapor pressure. And like others already wrote: it can be calculated by weather forcast.
my thoughts exactly.
Design for a bad day and it may never happen.
I was a geology student at the University of Missouri: Rolla at the time of the collapse. We spent a lot of time discussing this. Great video describing what happened.
I was at Rolla from 2002 to 2007 also, awesome to see a fellow alum here!
It’s a pleasure to see this, I’m a St. Louis resident and I go to Johnson Shut-Ins state park every summer with my family. it’s a great place to swim, no trees still have not grown in the entrance center, and the water has carved a scar into the mountain that is still noticeable.
10:15 As a train safety inspector once said goes: "One *ouch* is proceeded by ten *whoopsies* "
Preceded?
Preceded was right.
(If what they were saying was that an accident is made through a series of failures)
Also preceded means roughly that the thing that was just referred to happened after what is about to be referred to.
IE: the famous phrase "your reputation precedes you" means that the person heard about you before they met you.
Whoopsie!
@@dfunited1 Indeed. Perhaps we should proscribe a dictionary. Ahem.
Was he a toddler?
Things I love about this video: (1) the intensity with which you deliver the words "and what the investigations found would change a lot about the field of dam safety", (2) the fact that I am immediately 100% hooked and want to learn all about dam safety and how the field changed as a result of these investigations
When I heard that I was like “dam”!
This dam design is wild, I’m kind of amazed it functioned as well as it did for as long as it did. Thanks Grady you’re the best
I visited this site right after the collapse; still one of the most terrifying sights I have ever seen. An entire forest swept away in moments.
I operate a Pumped Storage Dam and we have training about this incident! We have automated sensors AND a live camera to physically verify the Upper Reservoir level. We also have a spillway as a last resort lol
Found your channel whilst helping my kids with their science assignments. Just subscribed. Incredible research stuff you have, with very substantive background and historical details. Well done. Greetings from Port Moresby, Papua New Guinea.
1:06 - There's no need to swear, Grady.
"Feel free to ask any of your dam questions at the end of the dam tour."
he really didn't need to say it so often; he's enjoying it
Did it in middle school 30 years ago...Still funny. I wonder if the dam store where I used to buy my dam bolts is still open?
@@prefect742-Dam if I know
😂😂😂
I live a few miles from Tom Sauk. I have flown my airplane over it several times. The entire hillside is still completely stripped. There are huge boulders scattered in the fields below it. It's wild looking.
@@luciustarquiniuspriscus1408 West side
@luciustarquiniuspriscus1408 it's been a while since I've been that way. Looks like they have added more fill over it. The field to the west still shows boulders though.
You think they'd be mandated to replant seedlings/trees to retain the landslide area?
I love this because I'm a raft guide who works on a river similar to this. Having an upper reservoir seems so unique to most people, but it seems to be the more efficient use of water if you look at energy demand and production. Thank you for such an informative video. I wish more people would see this. Some people think the river runs in a circle... I say "sometimes..."
You ain't being safe unless you're being dam safe.
dam right
Take my upvote sir
This was a great dam video!
Whoever said engineering isn’t a comic nursery?
This reply to your excellent comment isn't worth a dam.
I backpacked the Taum Sauk trail a couple years ago that runs around this, with no prior knowledge of it existing. Atop one of the adjacent peaks you get a great view, but man was it quite the sight to come upon... Almost gave you an uneasy feeling, but no doubt an engineering achievement.
I remember sitting at the top of bell mountain and seeing this big concrete wall and think hmm I wonder what that is
@@michaelthomas7999yup same, like what the hell is that ? Then we did the Tom Sauk section and were like why do they have signs saying if you hear an alarm run straight uphill. My buddy sent this and now we know.
Hey Grady, I live in Asheville. Over the past couple of weeks, I've seen water completely destroy our infrastructure and watched crews scramble to repair it.
It would be cool to see a video about how large amounts of water can overwhelm and damage things such as underground pipes and utilities, roadways and water treatment plants and how it can be prevented.
This is the best dam safety video I've seen all week
I see what you did there. 🤣
@@abpsd73
Beat me to it!😅
after pouring over many others i agree!
Dam shame this happened. Dam it.
I bought a project truck in the area about 10 months ago. On my way home is when I first noticed the structure. I had no idea what it was, but it looked absolutely magnificent and monstrous. I had to find a spot to pull over and look on satellite imagery to find out what it was and was totally amazed! I had no idea such a reservoir existed. This is the first time even hearing about the failure. Thanks for the info!
explained the why and how and got to the tragedy all before the first minute mark.
instant subscribe
I had to go to college to learn about engineering disasters. That was back in the 90s. I visited Johnson Shut Ins as a child and coincidentally I was there just a few years ago. I never knew about this catastrophe until I watched this video. There's a lot of value here.
I'm glad I'm not the only one there that really should have known about this when it happened.
It's amazing how it really didn't get any press to speak of.
Not from Missouri?
@@Hey_Blinkin I am from Missouri but I lived elsewhere when this failure happened. Nonetheless, I'm shocked that I didn't hear about it.
I used to live right near here, this was the BEST technical description of what happened that I've ever seen! Thanks
Me too. Had the taum sauk reservoir broken open on just the right side, it very well could’ve took out my home. I lived there when it broke open too.
As a nearly 30 elementary music teacher I find listening to stories like this astonishing! My mind is blown by the capacity of innovation humans can design. I know this was a failed “project” but it’s like many things in my mind that seem inconceivably impressive.
Thank you for sharing these types of videos and stating them in a manner that “simpler” minds can understand!
Grady.... I'm in my late 60's; but I want to share something - admittedly "..again" - but it certainly bears repeating: "The WORLD ought to see your videos".. I sincerely believe that. To that end, I have purchased your book, etc ... all in the service of doing what I can to further your channel. Just not enough words to express how highly I think of your efforts.
I live about 85 miles north of Taum Sauk. I remeber the failure. I have not seen a better explanation of the event. Well done. The camping at Johnson Shut-ins and water activities are great. The failure did a lot of damage, but the restorations to the park went well.
Visited it as a kid in the 70's. Shame it did damage to Johnson Shutins which was an awesome state park in that era. Seems like it was poorly designed from the start. Add poor maintenance and you have a recipe for disaster.
It’s been a while since I was there; didn’t they relocate the campground so that if this were to happen again it wouldn’t sweep away the campers?
@@martincox9691 l do not know. I remember the natural waterslide of the shutins and diving off of the cliffs around the corner from the shutins. I jumped from about thirty feet but people were jumping from what looked like 60 feet. I was so taken with the river that l recall nothing about the campground except we camped in it.
@@othgmark1 That entire area was pretty much destroyed, while it's still there, it's not the same at all and the water isn't deep enough in the area to cliff dive anymore.
@@mrrooster4876 Horrible news about that. It was such a unique area.
Love seeing you cover something that is so local and personal to me and my family! I was only a child when the disaster happened, but it affected everyone that loves the ozarks, and especially Johnson Shut-ins State Park.
Wow. Never heard of this dam nor this event. Great story and lessons-learned.
The lessons were learned long time ago. The constructors decided to ignore them.
@@noinfo5630 Yeah, crazy that there was no spill-way. That's like giving the universe the finger. Never works out well.
From the name, I thought it was in Cambodia, ha-ha! Can't believe this occurred in the U.S.
As Barney would say, "once burnt... lesson learnt, one mistake... a better cake..."
I've started working on Energy Security in Britain very recently and your videos have been very insightful in getting some basic understanding over the technicalities of such projects and the challenges they may face. Really appreciate the knowledge you share with us!
My family and I camped at the Shut-Ins yearly until this happened. We now stay nearby but still go every year. This is one video you don't see in the Visitor Center.
I am thankful this happened in the off season and that the Ranger/Administrator and their family were they only ones impacted and no lives were lost.
Being involved in a rural water system with a reservoir, I've seen the filling telemetry fail many times and an operator is not always present. While there is an overtopping mechanism, I'm not really sure the hillside below could withstand sustained flow. I think I'll open this question again. Thanks!
Small oversights 10:00 reminds me of the Challenger incident. The combined probabilities added to one big problem.
Excellent video. Great production quality, professionally presented. No self-serving, talking head promotional pitch at the beginning. Thank you! As a retired engineering from the nuclear power industry, I was aware of pumped storage for Nuclear plant but not for coal fired power production. Very interesting.
I was about to say "Sounds like a Normal Accidents scenario", then Grady chimes in! Excellent book, definitely a must read for anyone who wants to study failures in any system, especially complex ones
Nothing normal about this accident. There were several avoidable errors that allowed this to happen.
@@andrewjames4786 The "Swiss Cheese Model" seems more on point: a bunch of (relatively) minor errors and failures that, combined in just the right way under just the right set of (normal) circumstances, permits the entire system to fail.
You do wonder how anybody could see water over-topping the dam, without running with hair on fire to the engineer in charge. While it's true that it has to over-top _somewhere_ along the upper edge, not being curious enough to discover that the dry side is a full two feet higher indicates a "tell the boss and let him worry about it" mentality. (The boss failing to actually worry about it is the most egregious of the many errors.)
Almost seems more like a classic straw-back scenario
what in god damns name makes this a Normal Accidents scenario. This was complete incompetence at every "minor" issue. ONE TEST would have showed the redundant systems did not work. If this is considered a Normal Accidents scenario then we are forgiving the idiots that made those errors has if it was easy to make. You have to be completely brain-dead to implement these systems and not do it right or just test the thing.
@@jpdemer5 Disagree, the Swiss cheese model is about failures in mutually compensating *safety* systems, while this is a failure of holistic design because of the iterations and poor initial conditions.
All the holes in the Swiss cheese lined up, truly fortunate that it occurred off season.
A true understatement, I think most people watching this have no idea how bad that would have been. The main attraction of the park is basically a meat grinder, the lucky ones would be swept away
Yes, this whole episode is a good example of Jim Reason’s Swiss cheese model.
The acute geological change of the park makes Taum Sauk especially fascinating. Look at the boulder field!
Side note: deregulation is the precursor to catastrophe at a comical rate. The public neither knows about nor has an avenue to effectively express concern over how a company is operating. That's why you get "whistleblowers" instead of transparency into what's happening.
Wow, I use to camp at that beautiful state park and its river in the 90's and remember being disturbed that we couldn't go any longer due to this incident. Being a kid at the time, I never really grasped what had happened and never saw any photos of the area. Thanks for this deep dive into a disaster? and its aftermath.
I remember when this happened. We used to live close to Johnson's Shut-ins Park and went there a few times before the dam failure. I haven't been back since the disaster. Good reminder that I need to revisit.
1. put in level sensors in without measuring elevation!
2. no spillway
3. filling to tippy top
4. Lack of time sensitive shut off. "Hey why are the pumps running an extra 30 minutes today?"
All equals = Total gross negligence.
This project is not sound engineering at all, sounds like a bunch of sloppiness disguised as engineering.
Cracker Jack called; they want their stamps back.
I work at Mt St Helens. We have 4 earthen dams up here. 3 created by the eruption and landslide, and one man made to hold back sediment. An early retention dam failed in the 80’s. The army corps of engineers constructed spillways on 2 of the natural dams, and Spirit Lake, the most well known one, had a tunnel constructed to act much like the hole in a bathtub.
To this day the tunnel has issues (turns out in a. Volcanic landscape, there are faults… and the retention dam had to be built bigger recently. Nearly 45 years later and still dealing with it!
15:37 Not just a Dam Safety Officer, but a Chief Dam Safety Officer.
*chief dam safety engineer
I love learning more about Taum Sauk. My dad was a dam safety inspector for the State of Missouri - he was one of the first engineers on the scene. This completely avoidable (and totally foreshadowed) nightmare scenario could have been worse .. it could have been a summer holiday weekend.
Cool to see you make a video on this! A couple years ago, I hiked Taum Sauk with some friends when we took a trip to Missouri. Beautiful landscape.
Another excellent video by Grady. I have just one nit: At time 3:50, he says, "... but, there are no valleys at the tops of mountains". The Bath County pumped storage project took advantage of a valley at the top of a mountain for its upper reservoir. 🙂
There are plenty of pump storage facilities in the alps which span heights of more than 1.000m. Like Lac des Dix. But even if you could say they are on top of a mountain, they are still valleys, but quite far up a mountain.
I go to Missouri S&T, a state school with a massive engineering program. In our library, I found a massive thesis about this. The author wrote that she was halfway through another one when she decided to write this one because it seemed like such a horrible, crazy eventuality, but it needed to be studied and prevented from ever happening again.
I go to Johnsons Shut-Ins with my kids all the time, and have hiked that scour. I have been waiting for someone to make a good video on what happened there in 2005, thank you Grady!
So your telling me they knew the sensor could be inaccurate and they still didn't think it might be a good idea to keep someone there to watch it?
As a retired nuclear operator, they’re truly is nothing unforeseen; anything less is - less truthful. That’s the hard-core, no-bs, TRUTH.
You ought to cover Ellicott City, Maryland and how they've coped in the aftermath of back-to-back "historic" floods. I had friends watch their cars float away on the torrent from the second story of a bar they couldn't leave due to the floodwaters. An enormous mitigation project is in the works to try to "floodproof" the historic downtown. One issue that's been brought up is now rampant development on the hills above the town has decreased the amount of land available to absorb rainfall, leading to streets becoming waterfalls and rivers in heavy rains.
That was a high quality transition from content to ad, Grady!
Grady, I love your videos! They are excellent for me to play while I'm working. I'm in a crane for 10 hours a day, and your videos are pleasant to listen to a glance at for at least an hour daily. Keep up the great work! 😊
Grady, here in Chattanooga, we have one of the only pump storage facilities that are both on top of the mountain AND mostly a “natural” reservoir. Raccoon Mountain Pump Storage operated by the TVA utilized a retired quarry in addition to a wall created to close up the U-shaped reservoir. Check it out!
I was just scanning the comments to see of anyone would bring up Raccoon Mountain. Thanks for doing that. I'd never heard of pump storage before until years ago, when visiting Chattanooga with a friend, he said, "have you ever seen the Raccoon Mountain Pump Storage facility." It blew my mind at the time that power could be stored in this way but it also made such incredibly practical sense.
@@beeleo did y’all go up and see it?
The fact that Taum Sauk was never visited by Tom Scott feels like a missed opportunity
I think he did go to Dinorwig, a pumped storage in Wales.
@@otterylexa4499 I do believe you missed the joke
Imagine what a great opportunity it would be for Haliey Welch to visit it. Hawk Tuah Taum Sauk. /s
@@otterylexa4499 dinorwig doesn't really sound like Tom Scott.
His last name is Scott, not Sock.
As a retired nuclear operator, they’re truly is nothing unforeseen; anything less is - less truthful. That’s the hard-core Noble truth.
All large system designs need to include a document entitled "How could this go wrong?"
Failure Modes and Effects Analysis
@@lukefrahn8538And someone blue collar needs to make a version that every worker has to read
Oh man, I remember when this happened. Pretty big black eye for Ameren at the time, but we learned a lot from the whole ordeal overall.
I remember Ameren's efforts to get its customers to pay for this by raising our rates. I hate Ameren with the white-hot heat of a billion suns.
Thanks again Grady. I like the way that you are matter of fact about the dreadful human foibles that create such disaster...never preaching, just explaining. No rants, just calm relating of facts.
0:43 I think this is actually the first time in my life I've heard "undermine" used in a completely literal sense 😛
As someone that spent a few years inspecting foundations and designing upgrades, mostly related to fixing settlement, I saw a lot of undermined foundations and footings.
EDIT: It's always due to water as well. During a large rain storm see where all the water is running off your roof, or your concrete patio, etc, and make sure it isn't going by your house or garage or anything supporting a lot of weight.
It was the way of attacking castles and other fortifications. Hence the verb.
@@hughoxford8735 makes sense. For some reason I always conceptualized the "mining" part of it as a much bigger sort of...well, mine-sized hole! Always seemed like a horribly inconvenient way to try to get at somebody, but your explanation makes more sense 😝
Wow, that really Sauks.
*soaks
It does, but could also have been a dam site worse
Taum it
*socks
Good one, Grady. Thanks. Major control system failure but right before you said "spillway" I was thinking they should have had a smallish one that would dump into the lower reservoir with sensors (or camera) in that to detect spillage. Like so many of these types of failures, it's usually a chain of events to blame that are perfectly visible in hindsight.
I can’t wait for your video on the dam failures in Tennessee and North Carolina
They’re probably a couple years off.
Interesting. Near my hometown in Germany lies a similiar facility, the "Pumpspeicherkraftwerk Geesthacht" which is around half the size (3.8m m³) of the Taum Sauk facility and was built in 1958. Glad to report there have never been any issues with it (other then complaints of environmentalists about fish getting sucked up in the pumps).
Maybe the Germans put better water level sensors in it. Probably get them stock from SICK.
Very articulately and intelligently disseminated Grady. You are so interesting to listen to. Many thanks from Australia.
This is going to be a good one! Johnson Shut-In's is a state and national treasure! It's a shame what happened, however I think the state made some upgrades to the camp sites after the power company settlement. They now have cabins, which I don't recall any being there when I was there as a kid. Anyway, there was a lot of arrogance on the part of the power company on the original dam. That being said, we need more pumped hydro in this country, and I hope this is a learning lesson.
Batteries perform the same task as these dams, and are far easier to deploy. There’s very little pumped storage being built.
@@benoithudson7235 Batteries work fine but they don't have the capacity like pumped hydro. The main drawback to pumped hydro is the amount of head pressure needed in order for it to work. Usually cities don't have the amount of fall needed in order to make it effective.
Great Missouri outdoors!
@@adammuncy8475 : A single battery cell has a lot more storage capacity than a raindrop. Doesn't matter, because the grid doesn't rely on a single one of either, it relies on huge numbers.
Utilities and related companies have clearly decided that batteries is where it's at, because over the past few years, they dramatically increased the amount of storage they're buying and it's almost all batteries.
17:49 - "There's no such thing as a purely natural disaster when it comes to flooding"...very interesting. Never really thought about it. Wish you would have elaborated on that some.
That also gave me a little pause, like... really? But yeah, all rivers have flood plains, that's just the natural coarse of the river. We build on those flood plains and try and control flood water, but that is a purely human endeavor. Similar concept for tides and storm surges, we choose to build there, the water is just doing what it always was. I would argue, tho, that now with climate change and larger and more frequent hurricanes, some places that might otherwise have rarely or never seen a storm surge, will now be destroyed, so in that respect, that is human-caused flooding.
Grady isn't prone to hyperbole so I give him a pass on this one.
Humans shaping the land or choosing where to build infrastructure comes into play. Though there are times flooding destroys only wildlife, some may still find human components.
@@kindlin the problem with your conclusion is there aren’t larger and more frequent hurricanes.
@@brady3474 lol.... ok then
Hi, I love your videos and enthusiasm. I'm a software engineer, I have no knowledge at all about engineering but software. I love how you explain things, which makes me interested in knowing more. Curiosity is contagious.
I really enjoy watching your videos about engineering and even though I'm not an engineer at all I still like listening about places
like the Taum Sauk Dam in the Ozarks and it's eventual failure
have a great week and thank you.👋☕🖖🇺🇲
I love this channel and look forward to every video!!!
Dude I love your cadence and flow of information. Very well produced and wonderful to watch and listen to!
8:46 ahh, the classic "we'll fix it in the software" strategy.
When I was a kid in Boy Scouts we would camp in the group camping area at the far northeast side of the old campground setup along the creek… it would have been a deal if we were there when the water came.
This was well done , like many others, this was the first I’d heard of this project , it’s failure and consequent rebuilding, let’s hope they’ve got it right this time!
All the best Jules 👍
Uh-oh, the xylophone intro music… 1:23
☝️🤓 music
lol 😂
That’s a marimba, good sir.
9:38 I am not an engineer, but seems a simple camera feed to the operator room could have solved this issue....
Only if the operator checked the monitor. Being human he probably would not have done so after the first month or so on the job. It still needed a spillway, and a very simple safety cutout.
On a chemical plant I worked on we had a tank overflow. It had a high alarm but the operator missed the alarm, didn’t switch off the inlet pump and the tank overflowed. So a pump cut out was added if the level exceeded the alarm by a few percent. Sometime later there was another overflow. Turns out the operators had started relying on the pump auto cut off to do the job, ignoring the alarm and not intervening manually. Wish I could remember the next step (was probably 30 years ago!). The moral is if you going to add auto cutoffs you’d better make sure of its reliability and its demand rate and design the cutoff system appropriately with the required reliability.
I was going to suggest overflow sensors, but it sounds like they thought of those.
*sigh*
A failsafe feature doesn't matter if it doesn't stop a disaster when the anticipated failures occur.
They try to get rid of any if at all of human operator and programmed it to function automatically, there were no human it operated on logic.
Or, like, that stuff that toilets use... You know, a sponge and cord to action a switch.
Over the years, I have always enjoyed your content. Really does a good job at feeding my curiosity.
0:59 well it's still a model, just in a completely wrong way...
There's no replacement for a nice, big E-STOP button ... also, paying attention to what's going on! Trusting PLCs to run your gear for you is fine ... only if you're aware of and *ready for* the consequences when they fail.
This wouldn't have happened if they hadn't been so cheap. If they had installed a water level sensor every so often around the entire reservoir the settling wouldn't have mattered, the pumps would've shut off properly, and it wouldn't have overtopped. If your interval is every 100', even if one or 2 neighboring sensors fail you should still have plenty of them working to avoid overtopping.
@BobBobson failure mode cound be at the plc not the sensor. Mechanical fail safe seems safer, spill way for not if but when. Also the settling of the wall, 2 feet, wasn't detected by those sensors.
How do you push a button when you're not there?
@@BobBobson Grady is on the money that this was a Normal failure. Anyone looking at the design and management would predict there could easily be a failure, just like how if you look at the reporting on Boeing management it's no surprise their planes are breaking.
@@noinfo5630 As Grady pointed out, observation during the last few minutes of expected fill capacity is a pretty small labor input, especially in light of the consequences of failure. Someone made a decision NOT to pay for a worker to do that and - to no engineer's surprise - it came with consequences ... just like NOT hiring an outside process automation expert to review the PLC/sensor configuration for potential SPOF or other errors.
RUclips recommended this video, I'm glad it did! I don't know much about dams, but I found it very very interesting. Thank you for making it!