The Most Dangerous Dams

[@TREKLlN]

When I was 17 I got caught in a natural forming keeper while kayaking on the Colorado. Got out by grabbing the large rocks on the bottom and pulling my self downstream. Felt like I was under 10 minutes despite it being 30 seconds. A truly terrifying experience.

[@arthas640]

this is why i usually think its a bad idea for people to kayak on a river they're not familiar with without talking to locals first. They demolished an old weir near where i live because we get a fair number of tourists who'd go down a popular river and get sucked into a keeper that was already there naturally but made worse by the old weir. It looked like going down a steep but managable slide but large trees used to get sucked down to the bottom so kayakers could easily get sucked down. My mom said one of the last people to die died because he got tangled in some branches or brush at the river bottom at the end of the slope and he couldnt escape.

[@TheOliveBranch7]

Nice job tho man. Stay safe.

[@leonardmilcin7798]

You were lucky. Going down is the only way to leave the jump. It traps things that float, ie. separate from the actual flow of water at the bottom and up to the water that only circulates.

[@carazy123_]

Smart decision, dude. Your ability to think quickly could’ve saved your life, and I’m thankful for it.

[@officialjonas9163]

Glad u are still here to tell this story

[@scottwhitesell5476]

This video should be shared everywhere. Simple, concise explanation that could save lives. Thanks for another great video, Grady.

[@titanicbigship]

Fo it

[@shubhrantkhare9439]

Why you are sooo good😉

[@ls200076]

@@DjJooze Don't worry, low fertility rate would tackle that problem.

[@General12th]

@@DjJooze That's a terrible attitude.

[@DjJooze]

@@General12th thanks for your feedback

[@doodledeecloud9317]

Dams are sort of like roller coasters. The big, scary impressive ones are almost always are designed perfectly, with very low chance of failure. They're well maintained and kept up as to not cause disaster. But the small innocent ones are usually cheaper, not well kept up, and can go wrong and cause huge consequences.

[@guybrush20X6]

And much like said rollercoasters, a big one failing is national news but the injuries and deaths from smaller ones get less attention but quickly add up over time.

[@jazminemccoy7991]

Or natural disasters can make them collapse no matter how good it's taken care of oh and theres something called erosion which shifts earth's grown every so often which can cause it to collapse even if it's well taken care of lol

[@noelvalenzarro]

@@jazminemccoy7991 so then the small cheap flimsy ones are definitely going down while the large well maintained one has a chance of surviving and then if it’s damaged they would more likely catch it and fix it or just shut it down

[@katatat2030]

Maybe, but that's a different question than what the video is about. Lowhead dams are also dangerous when they're in perfect condition, the problem isn't maintenance.

[@demoniack81]

@@katatat2030 The real issue is that these dams look safe when they are not. No one would be dumb enough to try kayaking down the spillway of a 150m tall dam, but many people end up getting in trouble with the small ones. The comparison with roller coasters still stands, even if for another reason - the smallest roller coasters in a park are often the most jerky and violent. Large roller coasters with giant loops and inversions have carefully calculated curves and near perfectly smooth tracks, because if they didn't they would end up ripping themselves apart from the forces. They also have well designed seats and restraints which won't hurt you. The small ones can get away with a "that'll do" and often have jerky tracks, crappy hard straight seats, and a lap bar with less padding than a bicycle handlebar that WILL hurt your legs (especially if you're tall). I believe this is the reason why quite a few people are absolutely terrified of trying the large coasters. They went on the small ones expecting them to be really tame, and... _they weren't._ So then they see the absolutely gigantic one next door, and think that it must be 10 times worse and decide not to even try it because it's too extreme for them, when in reality it's really not.

[@edthegoomba]

When I was a kid my granny always told me not to stand near the weir since I'll "get sucked under" if i fall in. I now know what she meant, thanks bud.

[@jonathanhall4539]

Unless your granny was an engineer, she probably knew about the effect from having seen someone drown that way. Scary stuff.

[@dielfonelletab8711]

@@jonathanhall4539 I live nearish to a weir. It's pretty common knowledge to stay away from it.

[@edthegoomba]

@@jonathanhall4539 She lived next to the Barrow river in Kildare, Ireland. She'd go for a walk past the wier multiple times a week so yeah it's possible she saw the worst case scenario once, but she probably would have told me if she did. I'd say she was just told that it was dangerous by someone, or maybe she observed large pieces of wood becoming caught in the circulating water similar to the scale model shown in the video.

[@michaelcrockis7679]

Right in time!

[@superchuck3259]

@@edthegoomba Yep, your grandma likely observed the debris recirculating and recalled swimming in river current and how strong the current was she was seeing. Simple observation skills are critical!

[@Caesar512]

Dam jokes aside for a moment, this is genuinely terrifying. The wood in the small-scale model really sends the point home.

[@1TW1-m5i]

It's damn right scary.

[@electronpusher604]

There is a dam I fish at that has claimed 15 lives. I once hooked a log stuck in the current with 150 lb test line. I tried to pull the log to me, but the line broke before I could free the log...

[@spectre2381]

Electron Pusher that’s freaking terrifying

[@Markus-zb5zd]

We have a lot of these dams where I live and my parents were pretty good at explaining that there is that trap, but not why it's there. thanks for the great video

[@Cerebrosum]

@@SimonWoodburyForget Except your assumption that everyone who watches this video already knows this is wrong. It's a public video, plenty of people who don't know are likely to stumble upon it, and learn!

[@randywest1185]

As a recently retired civil engineer, I can say with some authority that was a truly excellent presentation, both technically and graphically.

[@edwardsmith7131]

THIS video SPECIFICALLY should be shown as a public safety video in all areas that have these dams. Not just because of public safety but because it reinforces the concept of Scientific Awareness™ of ones surroundings. Imagine how much more engaging a boring public school science class brushing over fluid dynamics could be if you can show IN SECONDS just how deadly ignorance of it can be.

[@DesertDog]

That's really smart

[@augustreil]

Edward Smith, Probably should be shown in every school as dams are everywhere, no matter where one goes ? Great comment !

[@connorbranscombe6819]

@@augustreil No they arent, Ive literally never see a dam or weir in my life, I live in South Western Ontario.

[@augustreil]

@@connorbranscombe6819, There are over 80,000 dams in the U.S. so just cause ya never seen one, don't mean they ain't there.

[@connorbranscombe6819]

@@augustreil Yeah and im saying the US and Canada and pretty fucking massive places, most people will never be in a situation where they are swimming upstream from a dam or weir lol.

[@willbernhardt4163]

Wow, this is genuinely terrifying. I’ve been an avid kayaker and canoer for years now, and I’ve shot just about every class rapids you can find in northern Canada and the boundary waters. Some buddies and I were joking about sending it over a small dam we found when paddling up in Minnesota one summer, but we just kind of brushed it off and decided a nice portage would be better. I know about the dangers of hydraulics in rapids, and I’m very good at spotting them and knowing how to avoid them, but I would have never even considered to be careful around such a small dam. This is a fantastic video, and needs to be shown to more people, if for no other reason than to spread awareness of this danger.

[@Turtle1631991]

Where are you from? In Czech republic these are fairly commonplace sadly but on the upside people can also google danger rating for each one on papular kayaking and canoeing locations. In fact these days a lot of them have a strip on the side for boats

[@demoniack81]

@@Turtle1631991 Very common here in Italy as well. I'm not sure I've ever seen explicit signage, but I'm sure I've always known that weirs were super dangerous. I'm not sure if I was told this in school or by my parents.

[@Antiwolle]

@@demoniack81the people from my kayak club they told me that at my first day in france seeing such a weir. In germany where I live they are not thaaaat common. But in france, it's like hell every river has at least 5 or 6 of this bitchy structures on 15 km of river, not all of them are fitted wir Boatslides, but nearly all of them are guarded by danger Signs luckily. Me by myself ended up 1 time in such a hydraulic jump, I did not pull the boof properly luckily which Was the reason why I ended inside there, but every good ww kayaker should carry a throw bag, which safed my life there.

[@dickybannister5192]

a tradegy last year in Wales. 10 inexperienced paddleboarders led over such a weir (low). 3 didn't make it. also the one of the trip leaders died.

[@Turtle1631991]

This is something I was warned about over and over ever since I was a little kid. In theory one escape technique is to swim out keeping at the bottom but good luck even having sense of up and down in that situation.

[@craftyasmr3227]

It's crazy how when stuck underwater you cant tell which way is up or down. Happened to me before and that 45 seconds I was under felt like a lifetime.

[@bcwbcw7649]

But has the risk of getting trapped in debris or rocks or broken pieces of old dam with rebar and other nasties - however sometime the only choice. Ofthen it is worth trying to get to the edge of the dam first where the flow may be distrupted.

[@RobBCactive]

The problem is river swimming you don't see turbulent water in time, the currents spin you so sucked under you don't know which way is up. That means you can dash your head against rocks. Had it happen to me on a rafting trip and had to hold my breath for a very, very long time and stay calm.

[@hetsmiecht1029]

If you fill your mouth halfway with water, would that allow you to feel which way is down?

[@anarchopupgirl]

@@hetsmiecht1029 it sounds like a good idea, until you realise that once you're upside down, all that water'll go into your nose, causing you to cough and splutter all your air out reflexively

[@DanteYewToob]

I've always had a fear of deep dark water... but I'm slowly realizing that deep dark water might just be the safest water out there! Safe looking shallow rivers can sweep you off your feet, inviting looking natural warm springs have brain eating parasites, wimpy looking small dams can drown you with ease, and even a small amount of water in a pipe other container can easily have the force to kill or seriously injure and destroy. Water is scary. I'm gonna keep a life vest near my toilet from now on. You can never be too safe! ;D

[@simunator]

Most drownings happen in shallow water statistically

[@SiegePerilousEsauMaltomite]

Unless there’s a low head dam just before it

[@ArKritz84]

simunator please elaborate. Most people who spend time in water, do so in shallow water.

[@kyle18934]

@@ArKritz84 the more experienced will problably go to deeper parts, while the less experienced see shallow as safe and stay there

[@jdrok5026]

Water is much like fire beautiful to look at and deadly to anyone who dares to not respect it. Oxygen is also deadly capable of poisoning you and causing sever health issues with high concentrations for long periods of time.

[@AuthenTech]

We had a few of those where I grew up, and I remember, very sadly, at least one (maybe more) people drowning in that exact scenario.. very small, shallow dam, but dangerous indeed. Great video, and definitely worth sharing.

[@uruiamnot]

To be honest, this looks a lot like Six Flags and their ubiquitous "flue" rides.

[@Horizon2779]

This is kind of weird, I legit almost drowned in one of these things a month ago. It was terrifying, so glad I didn't get sucked in completely.

[@joshanonline]

I lived near a fairly large river that had a large Dam around 60 meter wide, a medium one around 20 meters, and several smaller ones. I never heard of anyone drowning because they couldn't get out of the swirl. The trick was to just dive and let current take you but place hands in front to block rocks. I played in all these Dams all my life, it was just fun. Although there was one case where a teenager got sucked by the medium Dam right in front of me, and I couldn't grab his hand in time. He slid down 10 meters, thrown away for another 3 meters on top of rocks, and broke a leg, so he couldn't get out of a swirl nearly 15 meters wide filled with trash. It took me a while to get to him, but I got him out easily. Just used the circular current itself to swim out while pulling him. Meanwhile, 8 of his friends watched from afar, and one thanked me dryly as if it was somehow my job lol.

[@marcusosappus]

When I was a teenager back in the 80's, I would hang out at a low-head dam on the Comal river in New Braunfels, TX. I learned that if I got stuck in the jump, I could dive underwater as deep as I could and I would get into the supercritical flow and it would spit me out beyond the boil. It was very counterintuitive to do that, but it helped me 'save' quite a few people who probably would have drowned if I hadn't grabbed them and pulled them under the water with me into the fast-moving flow. Most of them were very grateful to be out of the death trap. Others thought I was crazy, but I had lots of fun playing in that dangerous current once I realized the trick to safely exit the jump. I recently returned to that spot and thankfully the city has put up markers and safety rope to keep people from accessing the low-head dam.

[@dustinstone5188]

The weir in my town has claimed many lives

[@icefloe1337]

This channel literally motivated me to pursue a career in civil engineering. Submitting my BSc thesis next week, keep up the amazing and inspiring work, Brady!

[@Outlawstar0198]

UPDATE?!

[@boriscrisp518]

"All these factors added together create a situation that is impossible to survive!"..... *lighthearted music plays*

[@InTheFilth]

Have two of these dams on the river next to my apartment. Never knew how dangerous they were.

[@matejhosner1980]

Uggggh, they are the nightmare of every kayaker. Stay away from those.

[@cdgonepotatoes4219]

Here in Italy you can see all sorts of abandoned low head dams and water elevators (or whatever they're called) down the length of even the smallest of rivers, it's ridiculous.

[@kint87]

Im a kayaker in france and ive seen several peoples died in these, cause of lack of signalisation for tourists. Also some dies triyng to save others peoples A death trap for any living thing If you see anything trap its a security rope you need, dont go by yourself

[@MrToradragon]

@@cdgonepotatoes4219 It is not strange, they once were used for obtaining power. Best thing you can do is to use them again as it will save significant amounts of coal/gas in the long run, lifespan of water turbines is well over 50 years and generators could be used for over a century with good maintenance.

[@TheJttv]

@@cdgonepotatoes4219 do you mean locks?

[@shogged]

We have one of these in Calgary Alberta. When I was growing up, you’d hear about tourists dying every single summer because they didn’t know the dangers of the hydraulic jump. Now they’ve redone the dam and it’s been a few years since the last fatality.

[@shogged]

@BUMBOCLAP BEATS glad youre still with us brother

[@adamc.sieracki4145]

I remember hearing about like a fatality a month on the news.

[@KeithHanlan]

If I was a teacher, I would show this video to every student in grade 7 and again in grade 10. I can't believe I survived to adulthood. This is a fabulous demonstration of a common peril and a fascinating phenomenon. Thank you Grady.

[@cbremer83]

We had several low head dams near where I grew up. My dad had a great way to teach the dangers to us. We went down and he tossed large chunks of wood in above the dam and directly into the area behind it. Just we could see them get sucked under and pop back up in the turbulence. Most pieces stayed in the area for days or even weeks before disappearing.

[@Wavelover33]

That’s a long time to spend with your dad

[@amygdala51]

@@Wavelover33 lmao

[@SusiBiker]

As an ex-kayaker, was just trying to explain the hydraulic jump and why I always avoided water-boil on certain sections of rivers. A perfect explanation of the dangers. Thank you. Subbed.

[@LobbySeatWarmer]

Wow. I literally had NO idea how dangerous weirs like this could be. Great video/PSA, dude.

[@mrplague9881]

The city I live in has a low dam on the south end of the city, it once helped raise the water level for the textile factories upstream. The textile industry left sometime in the 50's or 60's, but the damn remains. In the 1980's a teenager died while playing on the dam, and then 2 policeman died trying to save him.

[@deadshot4245]

@@skeletorrocks2452 talk to Washington state about that one. Dams helped kill the salmon runs and negatively affected the areas. there's places where they make sense and there's others where they do not.

[@deadshot4245]

@@skeletorrocks2452 good points to be made as well great response and highlights to further explore thanks bud

[@АртёмМаринченко-ц9с]

I’ve been near one of those dams, the river was deep, and looking at the boiling point gave me chills.

[@pigeon853]

Now I'm adding lowhead dams to my list of fears

[@rayherman2254]

OuottuotThe uotuotittoittoututttuttuouttutoutouotouououtouououotutoutoututuotututotoututuotutututuoutttuttouootutuootuououtututututoutotuotuttoutuotuotuoooutuotuttoutututotuoutotoutotutouttoutououotottoututouotttoutoutoutututtutouottuotutoutuotuotututuotututotuotututotutuotutuotutuotuotutouotututouttoutoutuotutuotutouotuotuotuotutuotutottoutouotutuotuotutoutouottol

[@SimonEkendahl]

@@rayherman2254 recovered from your stroke yet?

[@suxix7312]

Along with what? Butterflies and grass blades?

[@nevg5908]

You should add civil engineers that don't graduate knowing how to do basic engineering math...that's a thing unfortunately

[@jSyndeoMusic]

Add it to your list of weirs too haha

[@davidm.johnston8994]

You might have saved some lives there... I, for one, didn't know of that danger.

[@interlamer7480]

I kinda knew they were dangerous in some way, but I didn't know why and to what extent. Now I do.

[@jic1]

I knew about the danger of weirs. First time I've ever heard them called "low head damns", and I was hazy on the fluid dynamics of it, so I definitely learned something.

[@oddpotato4038]

they don't just happen in dams, they too happen in natural like the waterfall in my province. The waterfall has some similar characteristics as a typical weir and about 2 meters high but the only thing that makes it dangerous is that the river is actually just knee high but if you go near to the waterfall the depth suddenly drops (not a sudden drop though but it has a very steep slope underneath) and you could actually feel the current sucking your legs. If you know how to swim it would seem very harmless but sadly most of the ones that have drowned trying to swim didn't make it, most of them are kids and some drunk people. Because of this the locals already feared the waterfall and even legends sprouted over it (though I don't believe in any of those because nature has its own explanation about the things that they do and this vid is one of them)

[@drew_porter806]

@E V You can get sucked in if you get too close, jumping into the dam isn't the only way to get stuck

[@Superbug-tf8zy]

I'm still fucking shaking and terrified from that.

[@joystickmusic]

This is exactly how kayakers in my hometown drowned in a small river. I remember it was reported as mystery back then, until the scientists came in and explained exactly this.

[@joelcrafter43]

Oh god that just made me realize someone could probably get away with murder easily using one of these things. Scary thought.

[@nallid7357]

@@joelcrafter43 it would just be a cycle of the body resurfacing and submerging. The dark humor of me finds this funny, though.

[@frollard]

I commented similar to the last dam video...I work in emergency services and our weir was a meat grinder for decades until it was removed a few years ago. A weir rescue was a very very high priority version of our water rescue protocol. I'm so glad they finally took action to remediate the area.

[@DinnerForkTongue]

Did the doctor give a prescription of high-yield explosives?

[@verdatum]

I really cannot get enough of the hydrology. Ever since I bought property with a stream in my backyard, and probably long before that, it has been a topic that fascinates and delights me. As a software engineer, it is so far from my wheelhouse, but I love every time I learn something new in this realm.

[@superchuck3259]

Dam interesting stuff!

[@Nicholas-f5]

We can always renovate our wheelhouses. 🤓

[@povnw8985]

OP; Go over one on an inner tube and you will understand it just fine. That's how I learned. Dam near paid full price for that one.

[@superchuck3259]

@@povnw8985 Nice, Dam near! lol But seriously what saved you, holding on to the tube?

[@povnw8985]

@@superchuck3259 ; That's exactly what happened. I got rolled out of the tube and reached out to grab it on instinct. There were no warning signs. I got lucky.

[@Suburp212]

This should be mandatory viewing in all schools

[@clxvii_]

Where I before saw bridges and dams, I think I now can see, and appreciate, the art of civil engineering

[@DaCheapChimp]

I like that you make the Practical experiments, everybody's gotten too lazy and they all do it digitally. It's like a breath of fresh air, thank you.

[@windowsxseven]

ok boomer

[@MelvinGundlach]

Why would it be lazy to do the same thing digitally?

[@earthclad6833]

@@MelvinGundlach because it's more accurate

[@MelvinGundlach]

EarthClad What is more accurate?

[@NooneStaar]

@@MelvinGundlach I like seeing a practical example, I could see a simulation and it would work too, but I like seeing the piece of wood in the real life example as well.

[@matthewgroff433]

Being a former Volunteer Fire Fighter (almost 10 years) and Water Rescue squad member (about 3 years), I had training in Water Rescue and how to deal with Low Head Dam rescues. There are several low head dams in the area I live, a couple have already been removed. A few of them have had deadly accidents at them through the years. At least 3 kayakers have drowned while trying to "jump" the low head dam during a high water event after heavy rains. Several people have drowned after swiming around or near these same low head dams after heavy rains. And a few more people died at these same low head dams either getting caught in the "boil" while fishing, trying to retrieve a lost object that had fallen into the water, trying to save a pet/animal that fell into the water, and/or just swimming too close to the low head dam.

[@driveman6490]

*FOR SALE:* Kayak, only used once near weir of dam, in good shape, body included.

[@FDog16]

How much?

[@unnamed715]

Is the body male or female? Need to know for uh, science and stuff...

[@TheNewTimeNetwork]

Pickup location: Just below the weir, it's easy to get there.

[@XeonAlpha]

TheNewTimeNetwork leaving is a challenge though

[@TheMattc999]

TheNewTimeNetwork and how long has it been there? I mean, in this case, the longer it's been there the cleaner it is likely to be.....

[@kevinturner9401]

I'm impressed with the amount of effort you put into designing and bulding your models and then explain everything so well. Thank you. You are one of several people who make engineering look exciteing to me.

[@motorv8N]

Very important safety info - thanks for this! I’ve been boating for nearly 50 years and had no idea of this potential danger. People see a small dam and probably don’t appreciate the risk. That graphic showing someone submerged with arrows to represent the keeping turbulence would be an eye-catching thing to put on the warning placards.

[@krnlg]

Yes, I think that would be much more effective than a simple "Danger" sign!

[@ZoniesCoasters]

Pretty good dam video. I was disappointed you didnt talk about the dangers in the last dam video about hydraulic jumps. Glad you made another video.

[@ben28bosss65]

I would say, it was a pretty dam good video.

[@MARILYNANDERSON88]

My father took me on alot of dam tours on our dam vacations. He made earthen dams for erosion control. I grew up and became a dam engineer.

[@the_original_Bilb_Ono]

@@ben28bosss65 you beat me to it!

[@the_original_Bilb_Ono]

@@MARILYNANDERSON88 damn....

[@ZoniesCoasters]

@@chipsramek3868 what? how/why would an educational video on low head dams be trying to brainwash you?

[@MaartenvanHeek]

As a kid I was always very scared when my brother took me across a movable low head dam (with an access 'bridge' on top) where we lived, in part because there was only one railing that if I recall correctly missed in the middle, because it was a very narrow bridge, but mostly because of the little waterfall below. Now I know that I should have been even more scared.

[@wkdravenna]

You should live in utter fear!

[@maxshepherd8709]

As a surf instructor, beach lifeguard and kayaking instructor I’m a great swimmer who overlooked any sort of threat of these ‘Drowner jumps’ I got sucked into one and flipped around underwater for what felt like an eternity. (Probably only a minute). I got to the point where I gave up struggling and everything went quiet and peaceful. Miraculously I popped out downstream from the ‘stopper’. Following this, I had swallowed so much river water during that episode, when I managed to get dragged up the river bank by my friends, I instantly threw it up (and out of my rear end) Also, I had caught leptospirosis (Weil’s disease, comes from rats piss) from swallowing the water, keeping me bed bound for an entire week whilst unable to consume a even a mouthful of drinking water without throwing it up (or blowing it out from the rear). All this, then I had to get back in the sea to continue running surf lessons. It took me a split second to ignore the ‘No Swimming’ signs, then it took me years to regain all confidence in the water. If my lungs weren’t so strong, I would have definitely died on that day. Jumping out of an aeroplane with a parachute is far safer than getting in close proximity to one of these ‘Stoppers’

[@jonathancobb3522]

dam

[@lewisgann280]

I’m glad fortune was on your side that day max.

[@broklee]

Thanks for sharing

[@al906]

I kayaked over a small water fall and almost drowned because of this

[@Ur2ez4me81]

Al Explorer I watched a kayaker almost drown in one of these. The person was lucky that the water level was low at the time.

[@forcesightknight]

Almost drowned. That's why the flotation vest is so important.

[@kainenmattison3665]

@@Ur2ez4me81 low head damn will pull you under even.if you have life vest on

[@philipblake5609]

bruh moment

[@JL-pc2eh]

3 people died this week close to me. There is a spot where swiming is allowed close by and they swam to far down the river. There is a really small waterfall if you could even call it that. The waterpressure is so high they needed 2 days to even get the corpses out of it because they couldnt reach the spot where the corpses were catched. Its now planed to throw some big rocks in there to lessen the danger.

[@experiment506]

"Drown jump" They didn't want any sort of confusion did they

[@CrashB111]

"You will die if you swim here, zone"

[@haruhisuzumiya6650]

the human washing machine

[@nedaltrebor8553]

The signs near these types of dams literally say drowning machine.

[@DinnerForkTongue]

I mean, would _you_ give danger like this a more subtle name that's more prone to misinterpretation?

[@tjhess2]

Thank you for making this video. My family and I are avid kayakers, and encountered a low head dam on the Congaree River in Columbia, SC a couple of years ago. We weren't from the area and there was no warning signage. Coming from upstream, you can't see it until you're nearly on top of it. Two of us made it over unscathed, but the third got sideways and capsized. The river was in a low stage that summer, and between that and the life jacket, is the only reason my father-in-law and daughter survived. His kayak sank and we were able to pull them out of the water. We often think of that day and are extremely grateful we all survived having learned a very valuable lesson.

[@stephensnyder2559]

That spot you are talking about can definitely be dangerous. I have tubed down that river a few times as I live close to it. You are right. You can’t see it at all until on top of it. During high river times you can’t even see it’s there. They say it was just to keep large boats from coming up the river but I’m not sure

[@twocvbloke]

I have a poorly designed toilet that demonstrates this effect perfectly, water flows down the back of the bowl just like the flow over the weir, and, ahem, "objects" caught in the flow below just roll over in the turbulent water and can't escape easily, whoever designed that toilet knew nothing about fluid dynamics... :S

[@jic1]

You don't happen to live in the UK, and own a toilet made somewhere between 20 and 40 years ago, do you? They're pretty much all like that.

[@twocvbloke]

jic1 - Yep, in the UK, but nope, toilet is a modern "low volume water-saving eco-friendly" lie, takes two or three goes to shift an average job, compared to the 40-50 year old throne in the previous house that could shift it all in one go just by threatening the bowl with water!!! :P

[@karlscheel3500]

@@twocvbloke Actually, I have one of those older toilets, that's operates that way despite it being a _real_ water-hog. _Disgusting!_ :(

[@douglasaranda2010]

I have a two piece toilet that works better than the wall register ones here, never got clogged, the others once in a while requires a "little help", in simpler words, my water tank toilet uses less water and works better, win-win!

[@evanherriges4042]

Ok well I'm just glad I have a toilet

[@CatsMeowPaw]

As someone who recently took up kayaking and often visits rivers with weirs, I found this video very interesting and helpful.

[@superchuck3259]

Portage around them and save your life!

[@Matt02341]

Hi Grady! I would like to print a QR code to this Video at a local Weir Dam. This is intended to be a cautionary action and not to distract from the beauty and history of the location itself. I will work with local authorities to properly get this done

[@DinnerForkTongue]

Did you manage?

[@eyesofstatic9641]

Yes do update us!

[@trueriver1950]

Good plan!

[@aaron41]

I was a lifeguard in high school, and I feel like this is something I should have been taught, but never knew about. Thank you for the great video as always!

[@santiagorestrepo9504]

You have inspired me to become an engineer. Thanks

[@erylkenner8045]

That's so cool! As a fellow engineer, best of luck in this awesome field

[@brianhawkins]

That's great! It's always fascinating to hear what inspires people to get into engineering. For me, it was playing with Legos and Construx when I was kid.

[@Onebadterran]

Best of luck!

[@MamaMachanMapla]

Don't bother with others caring and all that jazz! You go buddy :-)

[@terryterrill657]

You can do it keep your head up

[@Monkey80llx]

Fantastic video for several reasons. As someone who is not an engineer but who's working life has covered vehicle mechanics and numerous construction trades,...thank you for making every video interesting and technically immersive without being too overwhelming for a layman. Brilliant content! 👌🏼

[@harristung]

I can see the sound absorbing foam on the background wall for better sound quality, love a man that seeks for perfection!

[@maxximumb]

That's engineers for you.

[@TheStackeddeck77]

@@maxximumb Optimist says the glass is half full, the pessimist says its half empty, the engineer says your glass is twice as big as you need.

[@michaeltempsch5282]

@@TheStackeddeck77 or filled with 50% water, 50% air...

[@AndyGneiss]

@@TheStackeddeck77 That glass has a safety factor of 2.

[@MrVonWilly]

I knew someone from my community who died in a situation just like this while attempting to save his friend. I had an idea of why this happened, but this video really gave me a better understanding. Great post, thank you.

[@squeakybunny2776]

Did his friend also not make it?

[@trenthink]

I found this story super interesting. When I was a kid, before and into my very early teens, we had a tiny dam on a local lake that fed into a river. As kids, we used to jump in just downstream and then fight our way up right next to the dam. This thing was tiny, maybe 40’ wide with an 8-10’ head, at most, and apparently only for controlling the water level in the small lake above it, but for me it is very easy to imagine getting caught in the current below the damn. What we used to do, as kids, was jump in right in front of it, and then work our way up through the cascade. This dam was really tiny, and there was some crazy stuff going on just below it, but if you could get past that it would sort of suck you into this spot right up against it, where you could stand up, maybe waist deep (as a kid) but totally under water in the air space just below the damn, watching all this water just pour over you. This experience for me, and I guess my friends too, was totally amazing and I will never forget it. But based on my experience it is very easy to see the potential danger, and it’s just like described in this video. Even in this tiny dam, there was a current just below it that would tumble you back in, again and again unless you fought your way out or right up against it. Apologies for my rambling story, but thanks for bringing up some really good memories of my childhood!

[@xqiuvmah]

If you are kayaking and want to go over a dam, here are some tips. First, never go over a dam larger then 1/2 your vessel. Second, go fast. You want enough momentum to carry you though the standing wave. Third, do the smart thing and Portage downstream. I have crossed them and it is an exciting rush, but not worth the risk

[@LostInThe0zone]

ian long this assumes that you have prior warning of the existence of such.

[@xqiuvmah]

@@LostInThe0zone most times you do. Every single one I encountered had always had signs upriver warning against them. Even if there are no signs, there are easy ways to detect them. By the nature of the low head dam, there will be a flat, calm section of river just above the dam with a sharp and distinct cut off. This section of the river will always be slower then the rest of the river.

[@LostInThe0zone]

@@xqiuvmah I wish that it was the case that enough of these damn lowhead dams were marked such that my daughter would not have died.

[@vidznstuff1]

Fourth, if you get caught in a keeper, swim to the very bottom so the boundary layer pushes you out of it

[@Gottenhimfella]

@@vidznstuff1 hmm ... that makes sense, if you do it early enough before exhaustion and inability to fill your lungs robs you of the possibility (actually full lungs would make it difficult, might have to do it immediately AND anaerobically)

[@firststreetoddities4427]

I've gotten stuck in one of those before but luckily for me I was tall enough to stand up. Water went right up to my shoulders just above.. It was very difficult to stand. Let alone trying to swim out of that.. I had a kick away from the back wall like a Olympic swimmer in I had enough thrust to get out

[@KyokuiGhostASMR]

I almost drowned in a dam when I was younger. I would've died if my olddr brother wasn't right there to pull me out. Never underestimate currents, especially in any sort of channel

[@matgonsale9781]

I think all colleges - civil engineer - should encourage theirs students to see your channel. Thanks for all the videos. Do tuned liquid damper for highrise building please.

[@CephalonOwl]

I'm majoring in civil engineering and i feel like the algorithm has given me gold

[@jamesmccann531]

Also be aware that these hydraulic jumps can also occur in nature, which is why you need to be very good at reading the water if you want to stay safe. Normally, natural hydraulic jumps are not as wide, but can trap you just as easily, especially if bent with the ends pointing upstream.

[@100GTAGUY]

James McCann I got caught in one river tubing in North Carolina on just a lil two foot "waterfall" going into a six foot deep rock channel about twenty feet long with still water on the outside, it wasn't much wider than the inner tube itself but damn was it powerful. I'd guess it was a natural hydro jump that the locals built up with rock walls to make a faster waters. I was probably stuck in it for about 45 seconds until I was able to kick off the rocks hard enough to make it through the turbulence and into the flowing water again. Even though I knew to stay calm from scuba training, I could feel the water pummeling my body and it did make me cough up some air and that shit is terrifying. Things like rip currents, undertow, how to escape fast moving water etc are all usually taught about in a variety of aquatic sports/rafting/survival/lifeguard classes, some of which I have attended. But this video is honestly the first time I've ever heard of the dangers of hydraulic jumps ever...

[@EmilyMeens]

My Dad is a retired civil engineer with a masters in fluid hydraulics. He always calls these “rollers”. Added benefit of an engineer Dad, knowing about the dangers of rollers my whole life. 👍 What a fascinating video. Thank you!

[@DanHaiduc]

5:57 "All these factors added together create a situation that's almost impossible to survive" 6:04 *cheery music plays, showing a model plank caught in the death trap*

[@ashishkinge7162]

🤣

[@janstormborn9699]

Me: damn its 1 am already? KZbin: the most dagerous dams

[@Nationof300]

• Jan Stormborn same here

[@clark57225]

@@Nationof300 Yes, all this information keeps flowing into my head with nowhere to go.

[@Helperbot-2000]

Oh dam

[@buddinglearner7085]

discovered this channel tonight and it is 4 am already ...not kidding this channel holds some value

[@haruhisuzumiya6650]

drowning machines

[@theKRB93]

Fantastic video! I had a true 'ah-ha' moment when you illustrated the effect with the little wooden piece, and it's apparent how much time and effort went into creating that model. It is perfect and a great visual aide. Liked and Subscribed and going to binge on some more of your content now!

[@seriouscat2231]

I like these videos too, but I'd probably have used colored beads to demonstrate the effect for a second time. But then it would have probably looked more cute than dangerous.

[@DerSolinski]

Thanks, was an eye opener. Even if I know the physics behind it, the practical model really brought it home. Scary stuff.

[@kevinbyrne4538]

Thank you for the simple, clear distinction between subcritical and supercritical flows.

[@DrewMoorman-ld9uq]

Hi Grady, I am a boy of 15, you and Brian at practical engineering are what I do to relax in my free time. I just wanted to say thank you for what you do, and to keep doing it, you say you’re inspiring, the next generation of engineers, I hope I’m one of them.

[@ilikeappleandtrains]

My Brain: Don’t say it Don’t say it Don’t say it Don’t say it Me: Dam that’s dangerous

[@Sand.Springs]

Dam thats dangerous

[@ArKritz84]

Every dam time...

[@tiltil9442]

It's a dam fact!

[@pepperpon3]

I was expecting G E K O L O N I S E E R D

[@monsterkicker291]

Dam-it

[@jonahd5195]

There is a dam that did this by my cabin. We walked down there once with my aunt and she threw in a leaf to show that the current won’t allow you to escape. They made it much safer by putting rocks and stuff in the circulation, but I and still terrified of it a good 10 years later.

[@PBeringer]

That it took until the six minute mark to drop the phrase "DROWNING MACHINE", and that it wasn't in caps in the title, is probably the most "un-KZbin" thing possible. That's impressive! ;) Love your channel (for myriad reason in addition to the above)!

[@anaxim1]

Solid videos that help foster a greater appreciation for the engineers that have built our modern world. Thanks, Grady.

[@douglasskaalrud6865]

I remember the dam in my mom’s home town when I was growing up. It held back three lakes and the water dropped from a former mill pond forty feet into a shallow creek that could take a much higher volume if need be- like spring runoff for instance. The dam was constructed in the crudest form imaginable. It was basically four culverts, forty feet long with two culverts stacked on the other two. There was a simple gate mechanism on the upstream side and the falls on the other. The whole works was set in unfinished concrete and there was a two-lane street across the top at a ninety degree angle to the culverts. It looked like something a farmer might put together to control drainage or something, not anything professionally designed and constructed. If it had failed it would have wiped out the main drag downtown with several historic buildings. I went to the falls once and saw how cheaply it was built and never went down there again. Somebody complained about this dangerous thing until the city and state got together and replaced it with a weir that is solid and creates a beautiful flow of water. The creek is deep enough to flow naturally and with three lakes collecting runoff it stays busy enough even in the summer.

[@ATruckCampbell]

Can you tell me what the town is called? I would like to see this pinnacle of human engineering.

[@douglasskaalrud6865]

@@ATruckCampbell New London, MN.

[@mojoemurphy]

In Missouri, South of St Louis, there's a park with an abandoned Weir and it has claimed dozens of lives. Another issue is there's a lot of underwater hazards that catch people, it's a super dangerous spot of the Big River

[@ErenSagin]

dozens you say? stupidity claim those lives i think. not the weir.

[@MannyQuacioua]

What’s the name of the place.

[@mojoemurphy]

@@MannyQuacioua Rockford Beach Park

[@mojoemurphy]

@@ErenSagin it's mostly people that come down from the city, this town is about 40 minutes South West of St Louis. The locals weren't usually the ones drowning or getting hurt, it was city families venturing out

[@MannyQuacioua]

@@mojoemurphy Thank you!

[@DFOwl]

I was canoeing along the moose river when my canoe got trapped in one of these. I was underwater in that cycle for about a minute and nearly lost consciousness when I got spit out by the damn thing!

[@IIISentorIII]

Ill recommend not canoe with moose, the are really dangerous animals and bad canoe buddys!

[@mobrage]

Day 1 of quarantine: I suppose KZbin will keep me from getting bored. Day 10 of quarantine: I've now exhausted all content I'm interested in. Gotta dig deeper. Day 30 of quarantine: I guess I'm now an expert in river management, mine blasting, car mechanics and construction. Ok then. *dons hard hat*

[@AndreasDelleske]

Day 300? You’re chairman in a state funded board reorganizing education of engineering in universities worldwide, setting up its first office on Mars?

[@christianmingle3394]

Day 360, you have ascended from the human realm of existence and no longer bother yourself with primitive human knowledge

[@njord1697]

Day 400 or so, what have you reached now?

[@seeco321]

Except nothing could be further from the truth and you’ve probably learned almost nothing compared to a free man.

[@Cat-bi1kp]

I live in a tiny town that no one's heard of, but we just hit national news this week for this. There's a small weir in the centre of town that can't be more than 2.5 feet high at low water, but there's been a lot of rain recently and it was in flood. Some paddleboarders from out of town decided it would be a idea to paddle through town and tragedy struck because they were totally unaware of what they were getting themselves into. Thankfully some survived, but it's so important for people to understand that water can be incredibly dangerous as well as fun, and you need to understand that before you do anything - even a casual paddle on a paddleboard down a seemingly innocent river.

[@catranger01]

There's really only two ways out, sculling out either end, or diving down to the bottom provided you can get past the boil.

[@TheFrenchMansControl]

I've been pulled under in a weir and got recirculated on a dam. I had zero idea until now how much danger I was in.

[@kevony619]

I love that ever since finding this channel, I absolutely look forward to all the videos and I find myself smiling whenever watching them. Thank you!

[@Cyba_IT]

I've often wondered why people get trapped in some dams and not others. Now I know. Basically look for the boil and make sure the water level in the lower part isn't as high as the cascading water. Great vid.

[@jorge16178]

Your content is beautifully educational. Thank you, sir, for your work.

[@greggcollins4215]

There are thousands of low head dams across the High Plains. Ranchers and Farmers will build a dam across a draw to hold back rain or spring water for cattle to drink. They are usually packed earth dams with a pipe inserted through the dam as a spillway.

[@insanejughead]

Grew up around these, but never knew what dangers they posed. Glad I'm afraid of water anyway. Thanks for the concise explanation!

[@MClollolol]

Hey! Your channel inspired me to pursue further education. Been out of school for many years. Getting a degree seemed kind of out of my league to start, so I'm taking a technologist program that allows transfer into 3rd year of a degree upon completion. Doing great so far, and almost done! So excited to continue onward. :D

[@NihilSineDeo09]

Keep it up. STEM majors/diplomas pay off

[@evancoleman658]

Waste of money

[@trep53]

Dams are about the scariest structures I’ve ever seen. Some of the low head dams in my area (NE Ohio) are being removed but at an all too sluggish rate. One additional complication is these old dams have accumulated some nasty silt/sludge at the up stream base. They need to be dredged before the dam can be removed. The upside is a safer, cleaner waterway for people and habitat.

[@ClemensAlive]

3AM Me: ... exists KZbin: *DAMS!!!*

[@frostdachshund9618]

Dam it KZbin

[@lidge1994]

Well...Dam!

[@alexkart9239]

*KILLER DAMS

[@shafx1987]

2:15am lol

[@easy_eight2810]

Dam it!

[@roby.3428]

I feel like I learned a critical survival skill. I do a lot of hiking and camping and have seen many of these dams myself. I will now be weary of them and keep an eye out for the "boiling point" created by this phenomenon. Thank you for making this video, keep up the good work.

[@patspencer5649]

Decades ago as a young man, I volunteered for our local rescue squad. We did search/rescue for water, and low/high angle rescue. One of the drills we practiced was a "boil line rescue." Keeper as you called it. Now that you have described the properties of a low-head dam. We had two boats. The one in front was a zodiak that motored up to the boil. It was tethered to a second more powerful boat pulling it backward at the edge of the boil so we could throw rope to the victim. Then, once they expired we deployed hooks to retrieve the body. STAY AWAY FROM LOW-HEAD DAMS. Not just for your safety, but the safety of those who have to come get you.

[@Draconisrex1]

Yeah, I got caught in one of those drown-jumps on the Russian River back in the 1970s. Came close to getting me.

[@QDWhite]

I have to say, your videos and home-made models make me take back every disparaging joke I ever made about civil engineering.

[@u1zha]

Wow, thanks for the practical demonstration! The most edutaining video in a long time. Should be taught in schools.

[@AnkhAnanku]

I know it’s not great for swimmers and kayakers, but that recirculation zone has some really really interesting properties. I gotta figure out how this effects river health in terms of suspended sediment, dissolved oxygen, HABs, pollution, erosion, etc...

[@andrewv5104]

That would be interesting to note. I wonder if the hydraulic jump increases DO in the winter in northern climates when the river is usually covered in ice.

[@AnkhAnanku]

So I figured it’s definitely a problem where the vortex scours the riverbed and re-suspends sediment, but then it goes and retains that turbidity within the vortex and ejects the larger, heavier grains. Those heavier grains would be the ones to fall more quickly out of suspension and get transported along the bottom and banks of the river without clouding it. That would deprive the downriver areas of softer sediment, but what it still provides isn’t the worst stuff... Wait. While one of the big problems with dams is that they trap sediment behind them, isn’t the sediment sorting usually the other way around? When the river slows in the reservoir, particles drop out of suspension instead of continuing to be carried downstream. Wouldn’t that tend to draw out the larger grain sediments first and leave the finer silts and clays in the water? Maybe this vortex helps rebalance the mix

[@Unformed8]

Had no idea a simple dam could be so deadly This should be a PSA

[@whatisthis839]

Same here, pretty much everybody likes to play in water so this should be more common knowledge. Never heard about it before.

[@NunYa953]

No way. There are alot of dumb people in this world, why would we want more?

[@Mrcharles.]

Tell that to the people of Michigan who are dealing with an absolute flood crisis.

[@stevenfromer3816]

Excellent demonstration.

[@Mhdogman]

Many years ago in my whitewater kayak I paddled back up close to this really rather placid looking natural weir that was going across a section of the Rogue River. The way it grabbed me and sucked me in where I didn't want to go really freaked me out. And it wasn't even close to big water there. Quite terrifying actually.

[@CrankyPantss]

The props and the explanation were both very well done. Nice job.

[@simpinainteasyRHEC]

Williams Dam on the white river in Williams (Lawrence County Indiana) is insanely deadly/dangerous. I can't tell you how many times I've seen cows, trees, tires, and unfortunately, around 10 years old I witnessed some rescue operations attempt to save other rescue folks try to survive a training exercise below the dam. It didn't turn out well. That place still intrigues yet terrifies me.

[@CaverJamie]

Williams Dam looks like the perfect drowning machine. Impressive to watch debris cycle through from the access walkway. One guy we know watched a basketball and a tire roll around in the boil until the ball went through the tire 😅

[@Are_you_eyeballing_me]

This genuinely terrified me.

[@juanmeleiro]

Just a suggestion: we’ve recently had in Brazil a disaster when a dam collapsed in the city of Mariana. It’s easy news to find. It’s a bit grim, but it’s the kind of thing that needs raised awareness.

[@HeBillsHim]

Juan Meleiro Or Spencer Nebraska.

[@cm0cm]

nobody cares about brazil

[@augiegirl1]

@@HeBillsHim When I selected this video, I thought it was a weird coincidence that this video was released less than two weeks after that. My hometown of Fremont (where my parents & brother still live) became an island during that flood.

[@TurtleSauceGaming]

Another very interesting video, especially as a rescuer in an area with many lakes and, subsequently, a lot of weirs. Hell, as a novice kayaker, it's good to know this.

[@b43xoit]

Thanks for explaining the causes of the danger. I hope listeners will be more impressed by that than they would by merely being told "It's dangerous, keep away."

[@Migueldeservantes]

Wow... almost a million subs!!! Best wishes. Honestly your videos are really inspiring, and educational, thank you for your hard work!

[@user-hh1tl4yq2b]

I feel I should add something here that might save a life. If you are unfortunate enough to find yourself trapped in the recirculation of a hydraulic roller, try to grab a breath, swim down as far as you're capable (your aim is the bottom of the dam), kick off with force downstream, and you will hopefully shoot under the roller and be able to pop up after the boil. This method is truly the safest way if you're proficient in the water, because intervention by others compounds the problem by putting another life or more at risk. Hindsight is 20/20, and this is all hard to put into action during panic, but it has worked. Good luck out there.

[@alchemisthere]

I've learned a lot with all your videos. Thank you for that!

[@wasdwazd]

These things have always freaked me out. Thank you for affirming my fears.

[@marthawhite3353]

Where I live along the Eastern Yellowstone, it is incredibly dangerous with the low weirs and many, many people have drowned over the years. Submerged trees and underwater whirlpools don't help, and it is in general a deadly stretch of the river. This video explains very well what they physics of the water are, fascinating - but be very wary and respectful to water !

[@SebastianWoodard]

There’s one of these up in Camp McDowell in Alabama. They have a beautiful trail leading out there and also have a place with kayaks. I never realized they were dangerous in this way. I thought they would be dangerous for people trying to cross across the top of them due to fast-moving water.