I can attest, as a 17 yr. old strong swimmer wearing floatation, I went over a 18" drop created by a gravel dredge line on the Clackamas River in Oregon. I was continually dragged back to the water drop line and pinned on the river bottom. I could crawl forward underwater toward the drop but not against it. Thrusting myself upward I could get a few breaths before once again being dragged under. Once totally exhausted I shed the life jacket to attempt to swim out, only to be dragged to the bottom again. I blacked out but was thrust out of the undertow because I no longer had the additional flotation. Incredible I survived.
Possibly, and I am the proof of a parallel universe. In fact after I passed out I saw everyone standing around grieving at my funeral. Also the little blip in the local paper about a teens drowning on Clackamas River. You decide.
Ron Dye Channel, wow, also have you ever had a dream like about a tree house and has 100% sure it's real then go check and it isn't there. I recently had a dream that I had maybe 9 years ago. I literally went outside to check if the house inside a tree was there. It wasn't. Kinda proof that only in dreams can you access a different universe. I don't know I gotta do my reasearch
how would anyone have proof they ALMOST drowned some time ago?? If he died we would have not heard the story, unless we were a local around that area that that time.
Johan sigurdson You do realise that what you ask for is stupid? If you don't believe him then go ahead and don't. but how should he be able to prove that?
the movement of the water in the kitchen sink is natural. besides, the entire system of tap water is pressurized naturally, by using water towers, or gravitational potential energy. there is nothing more natural than that, the only thing that is artificial is just the tap itself (as a man-made metallic fixture), but the whole system is passive in terms of added energy or other hydraulic properties.
This is fascinating, and kind of creepy imagining the terror/panic/anguish of the people who have been caught in this being represented by the Ken doll.
Here in Washington on the Yakima river we have a section that looks exactly like this. It looks so small and simple and I was considering going over it in my kayak so I'm very thankful you made this video. You just might have saved my life.
my brother in law is a fireman in Harrisburg pa where one of these little deadly waterfalls are on the Susquehanna River. He said if someone dies in one, they won't recover the body because of the risk. They have to wait until it decides to spit it out.
Here in the uk we tie a line and have an inflatable length of hose that we can feed along the hole, we can feed a firefighter across the base of the structure and have double failsafe plans for protection. In the event of any situation extraction can be made via any bank
Escaping these is possible but hard and counter intuitive. Life jackets become death vests because they cause you to float up directly into the current that flows back and slams you down. You need to force yourself to stay at the bottom while moving away. Otherwise you’ll just be pulled back into the current. Stay below and move away. Keep the current above you. This can be difficult because it will shoot you up, when that happens you need to swim as hard as possible down and away. You can improve your odds, but you’re still going to be at the mercy of the water.
Ah... But *Action Man* would not have got caught in the entrapment zone... Being a Brit, he'd have clawed his way along the bottom and eventually swam out of danger. Then he'd jump in his Land Rover and head over to Barbies, to give both Ken and 'G.I' Joe a good British pasting!
I just literally watched the original version of 3:45, very scary stuff. They were out trying to find the body of a firefighter that died the previous day. 2 of them died and 1 made it to shore. Low head dams are no joke.
that was the scariest bit, you can see the body language of 'oh shit this is fatally bad' when the boat is pulled towards that huge overflow before being sucked under. That'l give me chills whenever i see another low head damn
Not sure how this came up on my feed, but glad it did. Two of those deaths shown on that map appear to be at low head dam structures near where my grandparents lived. I remember seeing them as a kid, when we would visit, and being almost instinctively terrified of them. They are deceptively small drops, but I saw (more than once) whole fallen trees get caught in the churn at the bottom, and roll for days, being beat to pieces the whole time. It didn't take much convincing on the part of my parents to steer me far clear of those dams.
Bruh im studying business and can't watch a single presentation about it without skipping atleast half but still watched this full like I had an exam or something 😂
Very clear, great job. I hope you don't mind if I add a few safety points. First, the low head dams are the ultimate in "drowning machines" because they usually go from bank to bank with no still water eddy from which to perform a rescue or for the trapped victim to escape. On rivers you will often encounter the same kind of currents below rocks or ledges but, usually they do not extend the full width of the river. In many cases the edge of the "hole" turns downstream and if the trapped victim can work across the face of the wave can flush out there. When viewed from upstream holes with this "friendly" edge look like a smile. Other holes where the edge is turned upstream will not flush you and viewed from upstream they look like a frown..... whitewater boaters avoid frowning holes. In May of 2002 I found myself stuck in a class C hole on the Housatonic River. I was rolling up but, my kayak would get flipped again. I could not escape at the edges so I knew my only way out was DOWN. I pulled my skirt and dove for the bottom, the water passing under the hole flushed me out and downstream. Whitewater boaters discuss diving down, balling up and other tactics for escaping holes. Unfortunately, the lay person has not had these discussions and the last thing that will cross their mind in their fear is diving under water. BTW, have you considered what happens when the dam is built on an angle to the river rather than perpendicular to the flow?
Thanks for that info, davekingpt. I wondered if diving deep or balling up would help get me out of such circumstances. Of course, if I see the boiling water affect, I am going around and not tempting fate.
At the San Marcos, Tx Ice House dam (1973), it happened to me. The foam would not hold me up. I was trapped. Swimming to the bottom and kicking toward the downstream side was the only way out. They have since rebuilt the dam.
Second this. These concepts were taught to me early on when i started whitewater kayaking. With even a basic understanding of river reading, your ability to make safe decisions on the water is greatly increased. Having friends who know rescue techniques (throw bags and such), completely eliminate these kinds of accidents.
It’s called a spray skirt. Trust me, if you paddle a river, you need a spray skirt. It fits snuggly around the waist & the bottom fits around the cockpit of the boat.
Not sure how this got in my recommended box, (I enjoy an engineering video or two, but mostly electrical engineering) but I have to say, this is a really well put together presentation, and also a surprisingly relevant one. I do some whitewater kayaking and I have dealt with some "sticky" holes where this same phenomena was occurring, but for those they were always small so worst case scenario you had to swim out and get you boat and paddle later. I never really thought that much about where else such a danger might exist. I guess I never took the time to consider the danger of what looks like a relatively low risk water feature. (thankfully I never had to deal with one) We see a lot of "research" projects nowadays that seem to lack application, (obviously that is not always a problem) but it is nice to see someone taking the time to both raise awareness and also propose a solution to a problem that can and should be easily fixed but has not been due to lack of awareness. Anyway thanks for making this. Also that is a really neat flow channel apparatus.
Nice presentation. White water paddlers learn about drowning machines early on. In Toronto, weirs were put on the Humber and Don rivers after hurricane Hazel in 1954. I can remember two drownings on the Humber and four people and a dog at a weir on the Don. Three more drowned on the Credit River. That dam was blasted. The Don River weir was filled in below the weir and is now an easy run. Many of the people drowned after going in the water to rescue their dog. Usually the dog swims out and the owners drown. In the spring tree trunks and logs collect in the trough making it real tough to come up for air. If you are about to go over, try to jump as far as you can downstream WITHOUT your life jacket; then head for the bottom where the current can take you past the boil.
This would definitely be in the scariest top 5 extreme ways to die, right next to getting buried in an avalanche. Can’t imagine what was going through those poor firefighters heads right before their boat got eaten by the void.
As a layman I found much entertainment and educational value in this matter-of-fact academic video presentation. I wish more documentary and educational content were still made this way but since video delivery technologies became widely accessible in the mid-90s many production studios influenced control of the market by dictating specific format changes to ensure maximum return from the unproven technology shift of the day. Unfortunately the format changes initially were appealing but quickly proved to be regressive by 'glossing-up' and 'dumbing-down' style content. The format change has contributed somewhat to the demise of independent critical thinking as a cultural byproduct regardless of education background and nowadays we see larger and larger groups engaged in conspiracy theory logic(!) due largely to what they see as presentation of factual information. In this age of global information exchange it is ironic that the emphasis on qualitative value of educational content has given way to one of entertainment and presentation value. Now we see this trend more and more in news media, particularly mainstream. Education can be attractive and appeal to a mass audience but only as docudrama storytelling, thereby rendering it moot. Anyway, thanks for the informative video; I now know how to avoid drowning in a low head dam. Edit: but more importantly I know why it happens...
Me and my friend got caught in one of these in Missouri near St Louis. We were sucked under in that pool about 4 times (without flotation). It was a rather large waterfall too but I managed to push off the ground at one point and escape. Very terrifying though.
On the Payette river in Idaho, there's a rapid called "Go Left Or Your Fired" because there's a big bolder in the middle of the river. To the left is a safe rapid, I think the right is one of these (but naturally occurring)
Despite the fact I was daily swimming 75 yards at 6' depth on one breath, I was literally snagged by the power of a waterfall in the Caribbean. There was NO way out, I was literally locked in to a point about 10' out from the actual falls. Had a local not seen what was happening, I'd be long gone. No feeling like out of steam and sinking when a hand grabs your arm and pulls you out of the tempest. The undertow of a perfectly calm river can literally suck you under, too. When growing up I could swim fully clothed across creeks, but came the day when, on the landward side of a pier parallel to shore in about 10' depth, the undertow grabbed me when I was about arm's length from ladder....... it's literally suction downward. My friend spotted what was happening, grabbed a crab net and saved my life. Had I been alone the last of me would have been bubbles...... Excellent production here....... I worked in stormwater management/storm drains design for years; the detail herewith is really interesting.
It's a shame you built that great scale model of the real dam and then didn't test it in the video! Would have been great to see if it behaved like the real one on the news when scaled down.
Dunno how I keep getting to these kind of videos but I'm glad there's people on youtube actively putting together informative videos on how to not get killed.
This problem has been publicized in Minnesota, a state with several (possibly many) lowhead dams. It helped me appreciate the danger involved when DNR safety experts described these as "drowning machines." Few things in life are so dangerous while looking so benign.
A non-jokey observation - this explains why you sometimes see pieces of trash bobbing and floating at the base of a shallow waterfall without getting washed away. Very interesting!
I fell out of our raft on the ocoee river in a hydraulic a few years ago. Like being in a washing machine for 20 seconds until it spit me out. Seriously thought i was gonna die. The formation was literally called "Double Suck." Fascinating video!
Thank you for this video. A work colleague of mine and her best friend recently died whilst canoeing over a weir. They were very experienced. I wanted to understand what could have possibly happened. The Ken doll part of the video is shocking but informative, thank you.
I am in my 60s and I now understand how lucky I am to be alive. I did a lot of stupid stuff when I was young. Thank you for your efforts and great video.
A brook local to me has a high-level sewer crossing at just below water-level. To protect the pipe, a concrete dam was moulded over it with a steep rising face, narrow flat top and a shallow angle trailing face. At the foot of the trailing face there is a short distance of flat smooth concrete before a second much lower steep rise flat-top and steep trailing face moulded dam. I have noticed that at flow-rates from flood to nearly dry the circulating current is retained in a narrow pool at shallow depth, fixed distance within the confines of the structure between the two dams. There the bubbles are released, with very little air entrainment afterwards. All circulation is kept within that relatively shallow area and there is smooth flow with no scour afterwards. As kids, we used to play in and on the dam with no problems or fear of under-tow.
Probably one of the most valuable videos on the internet. I'll be looking for these for the rest of my life, and make sure others know too. Excellent pacing and presentation, and the flue demonstration really drove the point home.
Because of people taking time to put out good info like this , I am convinced it has helped keep me safer in my small boat on a large local river with such structures present. Thank you
Brilliant presentation. Congratulations. I have been dealing with flood-water channels and I find it worrying how much people do not know about fluid dynamics. I would suggest that people should know when water is translated and when water is circulated as that is what it is all about. To minimise the study I would suggest that people would learn what happens in fluids moving in pipes or channels where there are quick changes in pipe sections or square diverging or converging sections. In both cases, zones of translation and circulation occurs and this many be extended to understand open channels where air can be sucked in as shown in this video. Really all these dynamics occur in boats and planes and birds around the wings where the tips and the flaps and the slats cause the air to circulate and translate through going from high to lower pressures. Life can be saved if such dynamic functions can be learnt . In the case of water, our vision many help but in the case of air dynamics, one needs to know. The other day I saw a video of a light super-fast car overtaking a fast truck with a large trailer behind it. The driver of the super-fast light car was doing very well till he came beside the cabin of the truck where there was a heavy lateral flow of air being displayed by the truck . When this lateral slipstream caught the super-car, it was diverted to the crash barrier and the result was fatal. The truck was not even touched. If that super- sport- racing- light-car driver knew his fluid dynamics, he would have saved his own life, simply by knowing how to slow down at the right position and use his steering wheel to counteract the lateral force due to the " wind the truck created. Thanks for this video.
Interesting anecdote but I'm not sure that most people wouldn't be thinking about fluid dynamics when driving a car in a highway. Nor would people be clear headed enough to think about it when they are drowning. This knowledge is useful to avoid dangerous situations well before it actually happens rather than actively counteract them as the situation develops.
My home-river has two of those spots. One is a few hundred feet below the canoeing clubs boat house. The first thing I had learned is that your canoe must be longer than the "roll" in order to cross safely. And the second thing was "when caught, dive deep". By actively diving as deep as possible, you get into the current which completely exits downstream. This is not an easy task, especially when dizzy after a few real quick rounds up and down. So the best chance you have the moment you are caught.
In case C, the only possible escape is to swim out at the bottom, hugging the ground. But even in scuba gear that's terrifying. At least then you have the ability to adjust your buoyancy. Seeing that rescue boat without a line out the back (down stream) sent chills up my spine.
A kayaker tried to go thru a V canyon in up state New York, spilled, was pinned for weeks until river flow went down and dynamite was able to divert river. It cost local town about $10,000 to recover kayaker body.
just came across this video, I am preparing a water safety course for a search and rescue team, great information and video clips, makes understanding easier. I have been a river kayaker for 40 years so do have experience in low head dams.
Wow! I got here from watching airplane videos and then clicking on a video about sinkholes. Glad I did. I learned something new that may help me or others to be safe. Question is: This was 2013, where are you now, Ed Kern?
This taught me a lot about why objects get stuck over a waterfall, it taught me that such a scenario is called a hydraulic jump, and how to recognize the different types. Not only is this really cool, because it helps me understand why certain rapids are more dangerous than others, but it may just save my life someday. Thank you for this informative and educational video.
At first the idea of a drowning machine was horrifying and fascinating since it’s not a subject I was ever familiar with or even aware of until recently. But the more I find out about low head dams and how water flow really works it’s become so much more interesting. Thank goodness there are people out there who are trying to get these dams retrofitted and save lives.
+Maquina Caos Kayaking is safe, just look at where youre going to go before you do it. Geting an instructor or something is a good idea too Like anything there are risks, but if you take precautions to mitigate them you can do basically anything safely.
Like LemmingRush said, don't let this dissuade you. It's a lot of fun and it's pretty safe. Just plan your routes, and if there is a low head dam or other obstruction portage around it. Better safe than sorry, but don't live under a rock either.
Really interesting video. One factor that I would like to see explored also is the overall shape of the weir (UK word), straight across can be particularly nasty, but curved structures can be better or worse as lateral movement can get you to a weakness in the flow. It is the uniform nature of weirs that often makes them so much more deadly than natural features, which do not often go completely across the river. Also another solution which exists already is to have a separate canoe ramp for boat users to use which can just take them right over the weir at a shallow angle with a great deal of horizontal momentum with an escapable hydraulic feature at the bottom, I would also have thought his uses less concrete.
This is a great video and something I make my rookies watch at the beginning of every white water rafting and kayak season. We are about to start training again in April and I just wanted to let you know I will be showing another group of 12 young guides this video.
When I was a kid, there was this popular swimming spot in San Marcus that had a low head dam that was terrifying at times. I almost drowned when I got caught in the whirlpool then dragged down to the bottom just like shown in the video. Very cool and interesting presentation to someone who knows nothing about dams!
Same here. I was on the Comal River in New Braunfels when I was a kid and they had one of those dams where the water flowed over it but there was a section cut out of one side known as the chute where the water flowed through and not over which created rapids and was where everyone would go through on their tubes, but I went over the part where it flowed over and got knocked off of my tube and remember tumbling around underwater hitting rocks and such not knowing which way was up and out of nowhere someone jerked me up by my arm and more than likely saved my life, luckily the water was shallow enough on the other side where people could stand next to the boil without getting caught in it. I don't know if that dam still exists, it was in a place called Camp Warnecke and that was back in the 70's.
"If a retrofit cost too much, then the structure is unlikely to get retrofitted until problems with public safety have become evident" That's a diplomatic way to put it. In other words, we'll wait till people get seriously injured or die.. ..and then depending on the public backlash and amount of news coverage we might do something about it
So... Practical Engineering made a video about hydraulic jumps, and somehow even when this isn't in my field of study -at all-, I ended up here. Not like I'm complaining, in fact, I'm glad I watched this lol
Just got an idea. How about making a self raising flip lip. Basically just long piece of plate steel (or structure with the same function) coated in plastic or paint, on moving axis and kept up by air filled barrels. That way you get constant depth of your flip lip no matter the height of the tail water.
This was great to see, it's always baffled me how these dams still exist. Restricted access and public education would be the cheapest option, and would undoubtedly save some lives, but not all.
This is really well done. Very detailed, thorough, and clear. I felt that the part around 13:45 was particularly useful in pointing out indicators of dangerous hydraulics. Thank you for sharing this, and providing the opportunity for the boating community to educate ourselves.
Indeed, But people are not that boyant even with a life jacket on. What happens is they repeatedly are sucked under over and over, they can also drown on the surface because the water is so turbulent they just cannot get air. It’s called flush drowning.
@11:50 "His day is now ruined" Come on man, talk about euphemism. Ken "Yeah, so I, like, drowned, so i guess it kinda ruined my day." Hahahah Amazing video btw! Congrats dude! You are a credit to human kind.
More like, it's everyone that minimizes death. Pilots "bend metal" or "auger in." Person crashes in an unsurvivable fireball; people say "That'll leave a mark." Rockets undergo "rapid unplanned disassembly."
I remember back in 2018 in my country (malaysia) we had a Case C scenario where it took 6 lives of the fire and rescue scuba team. They were on a body retrieval mission for a teen that died a day before but the most baffling thing about the incident is how the scuba team’s supervisor gave them the command to retrieve the body located at the low dam despite after a heavy rain and it was late at night which caused all 6 of the diving team to lose their lives.
I had a modified flip lip one time when i was visiting Dallas. Good times. But seriously, this presentation is amazing. I don't know how i got here, but i watched the whole dam thing.
I have absolutely no interest in dams or how they work and all that but I watched the whole thing, very well presented and very concise. Thank you.
Ditto!
I have no dam interest
Therein lies the beauty of UA-cam.
Same.
Dams are here and learning about them may save your life. Information is never a bad thing.
thats a good dam presentation
You could even say it was a dam good presentation.
Damn
What a dam good pun
Weir in agreement
ThatAngularGuy now that one requires some respect. I’ve scour’d the internet for the perfect dam pun and here it is
I can attest, as a 17 yr. old strong swimmer wearing floatation, I went over a 18" drop created by a gravel dredge line on the Clackamas River in Oregon. I was continually dragged back to the water drop line and pinned on the river bottom. I could crawl forward underwater toward the drop but not against it. Thrusting myself upward I could get a few breaths before once again being dragged under. Once totally exhausted I shed the life jacket to attempt to swim out, only to be dragged to the bottom again. I blacked out but was thrust out of the undertow because I no longer had the additional flotation. Incredible I survived.
he must have died
Possibly, and I am the proof of a parallel universe. In fact after I passed out I saw everyone standing around grieving at my funeral. Also the little blip in the local paper about a teens drowning on Clackamas River. You decide.
Ron Dye Channel, wow, also have you ever had a dream like about a tree house and has 100% sure it's real then go check and it isn't there. I recently had a dream that I had maybe 9 years ago. I literally went outside to check if the house inside a tree was there. It wasn't. Kinda proof that only in dreams can you access a different universe. I don't know I gotta do my reasearch
how would anyone have proof they ALMOST drowned some time ago?? If he died we would have not heard the story, unless we were a local around that area that that time.
Johan sigurdson You do realise that what you ask for is stupid? If you don't believe him then go ahead and don't. but how should he be able to prove that?
I'm not sure how I got here from listening to stand-up comedy but I definitely learned something today.
Brendan Mazurik 😂
@21:38 isn't "Flip Lip" pretty much the definition of stand-up?
Probably the voice of the narrator.
Sounds more like a comedian than a Doctor.
Same
Word! I was just watching about railways in china. Time to sleep i think.
I will never look at a simple dam the same again... thanks!
Kenny Lam lol same
It's honestly simple death there dangerous
"Does this occur naturally? Yes! Lets look at an example: my kitchen sink."
boi
Crazy how nature do that.
I'm more curious about how kitchen sinks occur naturally.
@@salvatoreshiggerino6810, a waterfall maybe. A kitchen sink is an approximation of a waterfall.
the movement of the water in the kitchen sink is natural.
besides, the entire system of tap water is pressurized naturally, by using water towers, or gravitational potential energy.
there is nothing more natural than that, the only thing that is artificial is just the tap itself (as a man-made metallic fixture), but the whole system is passive in terms of added energy or other hydraulic properties.
You forgot to inhale.
This is fascinating, and kind of creepy imagining the terror/panic/anguish of the people who have been caught in this being represented by the Ken doll.
Here in Washington on the Yakima river we have a section that looks exactly like this. It looks so small and simple and I was considering going over it in my kayak so I'm very thankful you made this video. You just might have saved my life.
This river is just hours away from Yakima
@@elonmust7470 Your point is?
@@jamielonsdale3018 You talk to make noise
You should have gone. Thinning of the herd
@@thefrase7884 Sorry bud, god is on my side. I’m sorry you’re life is miserable I hope it gets better.
my brother in law is a fireman in Harrisburg pa where one of these little deadly waterfalls are on the Susquehanna River. He said if someone dies in one, they won't recover the body because of the risk. They have to wait until it decides to spit it out.
(s)AINT Cyanide Ah, Harrisburg is home of the Dock Street Dam. A 1994 news report claims that in the previous 30 year period the dam claimed 17 lives.
Gun Jew, I live by Falls pa and I have to say, the Susquehanna river is not to be messed with. I say if almost gained 100 feet of water
Ed Kern although natural in origin, have you looked at the whirlpool rapids near Niagara Falls?
Here in the uk we tie a line and have an inflatable length of hose that we can feed along the hole, we can feed a firefighter across the base of the structure and have double failsafe plans for protection. In the event of any situation extraction can be made via any bank
This happens on the Bull in south carolina all the time. There's a nasty little terminal hole there that has claimed several lives this year alone.
This was both very informative, and a little creepy in how dangerous such innocuous waterfalls are.
I live near the Bolton Strid no one has made it out , as result of an accidental fall Ever .
Exactly... Which is why a dumb sign is not a good enuf thing to prevent deaths!!!!
@@robcrowley75 The Strid is famous and it is especially creepy. It looks like such a little thing....
great, now I'll never run water in my sink and not think "that's a hydraulic jump".
that made me LOL
🌠 the more you know
Interesting presentation, and you are almost out of dish soap.
Wow... First the phone screenshot battery level curse... Now DISH SOAP! What have you DONE TO ME!!!
6:00
Haha
I hope he got more dish soap after so many years
Escaping these is possible but hard and counter intuitive. Life jackets become death vests because they cause you to float up directly into the current that flows back and slams you down. You need to force yourself to stay at the bottom while moving away. Otherwise you’ll just be pulled back into the current. Stay below and move away. Keep the current above you. This can be difficult because it will shoot you up, when that happens you need to swim as hard as possible down and away. You can improve your odds, but you’re still going to be at the mercy of the water.
I'm glad you used Ken as an example. GI Joe and Barbie will miss him.
Ah... But *Action Man* would not have got caught in the entrapment zone... Being a Brit, he'd have clawed his way along the bottom and eventually swam out of danger. Then he'd jump in his Land Rover and head over to Barbies, to give both Ken and 'G.I' Joe a good British pasting!
Should have used Aqua-man... he's familiar with this kind of work LOL:) OL J R:)
When I was in EMS Rescue we called these dams "drowning machines".
I just literally watched the original version of 3:45, very scary stuff. They were out trying to find the body of a firefighter that died the previous day. 2 of them died and 1 made it to shore. Low head dams are no joke.
that was the scariest bit, you can see the body language of 'oh shit this is fatally bad' when the boat is pulled towards that huge overflow before being sucked under. That'l give me chills whenever i see another low head damn
Not sure how this came up on my feed, but glad it did. Two of those deaths shown on that map appear to be at low head dam structures near where my grandparents lived. I remember seeing them as a kid, when we would visit, and being almost instinctively terrified of them. They are deceptively small drops, but I saw (more than once) whole fallen trees get caught in the churn at the bottom, and roll for days, being beat to pieces the whole time. It didn't take much convincing on the part of my parents to steer me far clear of those dams.
Watching this makes me realize how closely I dodged death during summer tubing...
Bruh im studying business and can't watch a single presentation about it without skipping atleast half but still watched this full like I had an exam or something 😂
LMAO
Very clear, great job.
I hope you don't mind if I add a few safety points.
First, the low head dams are the ultimate in "drowning machines" because they usually go from bank to bank with no still water eddy from which to perform a rescue or for the trapped victim to escape.
On rivers you will often encounter the same kind of currents below rocks or ledges but, usually they do not extend the full width of the river. In many cases the edge of the "hole" turns downstream and if the trapped victim can work across the face of the wave can flush out there.
When viewed from upstream holes with this "friendly" edge look like a smile. Other holes where the edge is turned upstream will not flush you and viewed from upstream they look like a frown..... whitewater boaters avoid frowning holes.
In May of 2002 I found myself stuck in a class C hole on the Housatonic River. I was rolling up but, my kayak would get flipped again. I could not escape at the edges so I knew my only way out was DOWN. I pulled my skirt and dove for the bottom, the water passing under the hole flushed me out and downstream.
Whitewater boaters discuss diving down, balling up and other tactics for escaping holes. Unfortunately, the lay person has not had these discussions and the last thing that will cross their mind in their fear is diving under water.
BTW, have you considered what happens when the dam is built on an angle to the river rather than perpendicular to the flow?
Thanks for that info, davekingpt. I wondered if diving deep or balling up would help get me out of such circumstances. Of course, if I see the boiling water affect, I am going around and not tempting fate.
At the San Marcos, Tx Ice House dam (1973), it happened to me. The foam would not hold me up. I was trapped. Swimming to the bottom and kicking toward the downstream side was the only way out. They have since rebuilt the dam.
Second this. These concepts were taught to me early on when i started whitewater kayaking. With even a basic understanding of river reading, your ability to make safe decisions on the water is greatly increased. Having friends who know rescue techniques (throw bags and such), completely eliminate these kinds of accidents.
@@aBADAasras The skirt is what keeps the kayak tied to your body - in order to escape you need to untie it to release your body.
It’s called a spray skirt. Trust me, if you paddle a river, you need a spray skirt. It fits snuggly around the waist & the bottom fits around the cockpit of the boat.
Not sure how this got in my recommended box, (I enjoy an engineering video or two, but mostly electrical engineering) but I have to say, this is a really well put together presentation, and also a surprisingly relevant one.
I do some whitewater kayaking and I have dealt with some "sticky" holes where this same phenomena was occurring, but for those they were always small so worst case scenario you had to swim out and get you boat and paddle later.
I never really thought that much about where else such a danger might exist. I guess I never took the time to consider the danger of what looks like a relatively low risk water feature. (thankfully I never had to deal with one)
We see a lot of "research" projects nowadays that seem to lack application, (obviously that is not always a problem) but it is nice to see someone taking the time to both raise awareness and also propose a solution to a problem that can and should be easily fixed but has not been due to lack of awareness.
Anyway thanks for making this. Also that is a really neat flow channel apparatus.
Nice presentation. White water paddlers learn about drowning machines early on. In Toronto, weirs were put on the Humber and Don rivers after hurricane Hazel in 1954. I can remember two drownings on the Humber and four people and a dog at a weir on the Don. Three more drowned on the Credit River. That dam was blasted. The Don River weir was filled in below the weir and is now an easy run.
Many of the people drowned after going in the water to rescue their dog. Usually the dog swims out and the owners drown.
In the spring tree trunks and logs collect in the trough making it real tough to come up for air.
If you are about to go over, try to jump as far as you can downstream WITHOUT your life jacket; then head for the bottom where the current can take you past the boil.
How do the dogs make it out?
@@NoriMori1992 They don't.
This is how I nearly drowned in the Yakima river in the early '70's My friend thought it was funny, didn't realize what had happened
Demonstration with the ken doll was fantastic, really makes the effects cleae
This would definitely be in the scariest top 5 extreme ways to die, right next to getting buried in an avalanche. Can’t imagine what was going through those poor firefighters heads right before their boat got eaten by the void.
As a layman I found much entertainment and educational value in this matter-of-fact academic video presentation.
I wish more documentary and educational content were still made this way but since video delivery technologies became widely accessible in the mid-90s many production studios influenced control of the market by dictating specific format changes to ensure maximum return from the unproven technology shift of the day. Unfortunately the format changes initially were appealing but quickly proved to be regressive by 'glossing-up' and 'dumbing-down' style content. The format change has contributed somewhat to the demise of independent critical thinking as a cultural byproduct regardless of education background and nowadays we see larger and larger groups engaged in conspiracy theory logic(!) due largely to what they see as presentation of factual information.
In this age of global information exchange it is ironic that the emphasis on qualitative value of educational content has given way to one of entertainment and presentation value. Now we see this trend more and more in news media, particularly mainstream. Education can be attractive and appeal to a mass audience but only as docudrama storytelling, thereby rendering it moot.
Anyway, thanks for the informative video; I now know how to avoid drowning in a low head dam.
Edit: but more importantly I know why it happens...
Me and my friend got caught in one of these in Missouri near St Louis. We were sucked under in that pool about 4 times (without flotation). It was a rather large waterfall too but I managed to push off the ground at one point and escape. Very terrifying though.
When you mentioned a Hydraulic Jump, I instantly thought of my kitchen sink, too. Good example.
That presentation is so dam good.
I saved my friend from one of these when I was a kid. So gnarly.
On the Payette river in Idaho, there's a rapid called "Go Left Or Your Fired" because there's a big bolder in the middle of the river. To the left is a safe rapid, I think the right is one of these (but naturally occurring)
Despite the fact I was daily swimming 75 yards at 6' depth on one breath, I was literally snagged by the power of a waterfall in the Caribbean. There was NO way out, I was literally locked in to a point about 10' out from the actual falls. Had a local not seen what was happening, I'd be long gone. No feeling like out of steam and sinking when a hand grabs your arm and pulls you out of the tempest.
The undertow of a perfectly calm river can literally suck you under, too. When growing up I could swim fully clothed across creeks, but came the day when, on the landward side of a pier parallel to shore in about 10' depth, the undertow grabbed me when I was about arm's length from ladder....... it's literally suction downward. My friend spotted what was happening, grabbed a crab net and saved my life. Had I been alone the last of me would have been bubbles......
Excellent production here....... I worked in stormwater management/storm drains design for years; the detail herewith is really interesting.
It's a shame you built that great scale model of the real dam and then didn't test it in the video! Would have been great to see if it behaved like the real one on the news when scaled down.
Sam Harper right! I was hoping they would test it
11:45
@@siqxyre8473 Sorry, I need to comment so that any time anyone else reacts/responds to this thread, I'll be able to cackle at your comment.
today in "shit i had no idea i was interested in learning about"
Finally, a worthy successor to Delta P.
L Haviland right
Dunno how I keep getting to these kind of videos but I'm glad there's people on youtube actively putting together informative videos on how to not get killed.
This problem has been publicized in Minnesota, a state with several (possibly many) lowhead dams. It helped me appreciate the danger involved when DNR safety experts described these as "drowning machines." Few things in life are so dangerous while looking so benign.
At first why I'm watching this.
&
At last thanks God I watched this
Good job 👍
This is a lifesaver presentation. I hadn't been that aware.
A non-jokey observation - this explains why you sometimes see pieces of trash bobbing and floating at the base of a shallow waterfall without getting washed away. Very interesting!
I fell out of our raft on the ocoee river in a hydraulic a few years ago. Like being in a washing machine for 20 seconds until it spit me out. Seriously thought i was gonna die. The formation was literally called "Double Suck." Fascinating video!
good info but swift water teams will not work unless they are sitting on top of it waiting for it to happen just body recovery teams
Ok, Nancy
Thank you for this video. A work colleague of mine and her best friend recently died whilst canoeing over a weir. They were very experienced. I wanted to understand what could have possibly happened. The Ken doll part of the video is shocking but informative, thank you.
I am in my 60s and I now understand how lucky I am to be alive. I did a lot of stupid stuff when I was young. Thank you for your efforts and great video.
those north carolina dam tubers brought me here my prayers goes out to the families
Glad I ended up here after a sleepless night. I definitely learned some interesting facts.
yea ive been stuck in a few of those in canoes..very dangerous..doc johnny
A brook local to me has a high-level sewer crossing at just below water-level. To protect the pipe, a concrete dam was moulded over it with a steep rising face, narrow flat top and a shallow angle trailing face. At the foot of the trailing face there is a short distance of flat smooth concrete before a second much lower steep rise flat-top and steep trailing face moulded dam. I have noticed that at flow-rates from flood to nearly dry the circulating current is retained in a narrow pool at shallow depth, fixed distance within the confines of the structure between the two dams. There the bubbles are released, with very little air entrainment afterwards. All circulation is kept within that relatively shallow area and there is smooth flow with no scour afterwards. As kids, we used to play in and on the dam with no problems or fear of under-tow.
Started with Delta P, went on to Mixed connection, toxic result. And now I'm here
Excellent video, thank you for sharing. It will be used for training.
Thanks again, James (Reno Fire Department, Swift water Rescue Team)
Just watched this whole thing. Don’t know dick about dams but this presentation was great.
Probably one of the most valuable videos on the internet. I'll be looking for these for the rest of my life, and make sure others know too. Excellent pacing and presentation, and the flue demonstration really drove the point home.
A UA-cam rabbit hole on quarantine brought me here.
This is very impressive and clear research, and beautifully presented.
this was so clear...i'm gonna use the info in my final year project...all of a sudden hydraulic jump can be understood quite easily
I was playing with the idea of kayaking over a low head dam. I'm glad I found this video, first.
Because of people taking time to put out good info like this , I am convinced it has helped keep me safer in my small boat on a large local river with such structures present.
Thank you
Fine presentation of valuable potentially life-saving information! Thanks!
Brilliant presentation. Congratulations. I have been dealing with flood-water channels and I find it worrying how much people do not know about fluid dynamics. I would suggest that people should know when water is translated and when water is circulated as that is what it is all about. To minimise the study I would suggest that people would learn what happens in fluids moving in pipes or channels where there are quick changes in pipe sections or square diverging or converging sections. In both cases, zones of translation and circulation occurs and this many be extended to understand open channels where air can be sucked in as shown in this video. Really all these dynamics occur in boats and planes and birds around the wings where the tips and the flaps and the slats cause the air to circulate and translate through going from high to lower pressures. Life can be saved if such dynamic functions can be learnt . In the case of water, our vision many help but in the case of air dynamics, one needs to know.
The other day I saw a video of a light super-fast car overtaking a fast truck with a large trailer behind it. The driver of the super-fast light car was doing very well till he came beside the cabin of the truck where there was a heavy lateral flow of air being displayed by the truck . When this lateral slipstream caught the super-car, it was diverted to the crash barrier and the result was fatal. The truck was not even touched. If that super- sport- racing- light-car driver knew his fluid dynamics, he would have saved his own life, simply by knowing how to slow down at the right position and use his steering wheel to counteract the lateral force due to the " wind the truck created. Thanks for this video.
Interesting anecdote but I'm not sure that most people wouldn't be thinking about fluid dynamics when driving a car in a highway. Nor would people be clear headed enough to think about it when they are drowning. This knowledge is useful to avoid dangerous situations well before it actually happens rather than actively counteract them as the situation develops.
How on earth did I end up here, and why did I watch it all? I must be procrastinating harder than ever before.
Great overview on hydrodynamics and its affects on different scenarios. Thank you!
Thank you. I'll be watching out for boil points when I'm on the river for now on.
My home-river has two of those spots. One is a few hundred feet below the canoeing clubs boat house.
The first thing I had learned is that your canoe must be longer than the "roll" in order to cross safely. And the second thing was "when caught, dive deep".
By actively diving as deep as possible, you get into the current which completely exits downstream. This is not an easy task, especially when dizzy after a few real quick rounds up and down. So the best chance you have the moment you are caught.
This reminded me of the fluid dynamics classes I had over 20 years ago. Nice presentation.
In case C, the only possible escape is to swim out at the bottom, hugging the ground. But even in scuba gear that's terrifying. At least then you have the ability to adjust your buoyancy. Seeing that rescue boat without a line out the back (down stream) sent chills up my spine.
This video was the first thing I thought of when I saw Grady's (Practical Engineering) video on low head dams.
This video is very interesting. Kayakers often call these features 'holes' and there are terminal and non-terminal holes.
A kayaker tried to go thru a V canyon in up state New York, spilled, was pinned for weeks until river flow went down and dynamite was able to divert river. It cost local town about $10,000 to recover kayaker body.
just came across this video, I am preparing a water safety course for a search and rescue team, great information and video clips, makes understanding easier. I have been a river kayaker for 40 years so do have experience in low head dams.
No American will ever forget the 2012 Salt Lake Watershed Symposium
I will never look at rapids the same again with this information
Wow! I got here from watching airplane videos and then clicking on a video about sinkholes. Glad I did. I learned something new that may help me or others to be safe.
Question is: This was 2013, where are you now, Ed Kern?
I don’t know how I got here. But I watched all 23 min and loved it.
This taught me a lot about why objects get stuck over a waterfall, it taught me that such a scenario is called a hydraulic jump, and how to recognize the different types. Not only is this really cool, because it helps me understand why certain rapids are more dangerous than others, but it may just save my life someday.
Thank you for this informative and educational video.
Great educational video. Since the video is almost 4 years old what progress has been made on testing the modified flip-lip?
Their website is still up, but nothing new after this video :(
I was wondering if they put flip lips in the middle of the dam height-wise how would that work? Kinda let the water splash out in all directions?
they have restricted access to the river and the local whitewater community is frustrated.
Reddit post about Drowning machine led me here. 3-4 videos later... ahh the interwebs
History is repeating itself reddit just brought me here too
Reddit sent me here with a video of a kid riding a bike over the top and being drag down the spillway into the jump. Don't know if it was a C or not
At first the idea of a drowning machine was horrifying and fascinating since it’s not a subject I was ever familiar with or even aware of until recently. But the more I find out about low head dams and how water flow really works it’s become so much more interesting. Thank goodness there are people out there who are trying to get these dams retrofitted and save lives.
Yes, as an open water swimmer who often swims in rivers, I have always known these as dead-head dams and have and understood them to be deadly.
Thanks for the presentation, I was considering kayaking for the first time in my local river but not anymore
+Maquina Caos Kayaking is safe, just look at where youre going to go before you do it. Geting an instructor or something is a good idea too
Like anything there are risks, but if you take precautions to mitigate them you can do basically anything safely.
Maquina Caos
There are also many different ways of kayaking
Some of them like flat water sprint are 200% safe
Ich Bins 200% safe? so in case of death there will be two of you?
No if you do that sport you will live 2times as long😁
Like LemmingRush said, don't let this dissuade you. It's a lot of fun and it's pretty safe. Just plan your routes, and if there is a low head dam or other obstruction portage around it. Better safe than sorry, but don't live under a rock either.
Really interesting video. One factor that I would like to see explored also is the overall shape of the weir (UK word), straight across can be particularly nasty, but curved structures can be better or worse as lateral movement can get you to a weakness in the flow. It is the uniform nature of weirs that often makes them so much more deadly than natural features, which do not often go completely across the river.
Also another solution which exists already is to have a separate canoe ramp for boat users to use which can just take them right over the weir at a shallow angle with a great deal of horizontal momentum with an escapable hydraulic feature at the bottom, I would also have thought his uses less concrete.
This is a great video and something I make my rookies watch at the beginning of every white water rafting and kayak season. We are about to start training again in April and I just wanted to let you know I will be showing another group of 12 young guides this video.
When I was a kid, there was this popular swimming spot in San Marcus that had a low head dam that was terrifying at times. I almost drowned when I got caught in the whirlpool then dragged down to the bottom just like shown in the video. Very cool and interesting presentation to someone who knows nothing about dams!
Same here. I was on the Comal River in New Braunfels when I was a kid and they had one of those dams where the water flowed over it but there was a section cut out of one side known as the chute where the water flowed through and not over which created rapids and was where everyone would go through on their tubes, but I went over the part where it flowed over and got knocked off of my tube and remember tumbling around underwater hitting rocks and such not knowing which way was up and out of nowhere someone jerked me up by my arm and more than likely saved my life, luckily the water was shallow enough on the other side where people could stand next to the boil without getting caught in it. I don't know if that dam still exists, it was in a place called Camp Warnecke and that was back in the 70's.
Very clear presentation!
its happened now at malaysia sept 2018, sad news.
Ah, yes...
"If a retrofit cost too much, then the structure is unlikely to get retrofitted until problems with public safety have become evident"
That's a diplomatic way to put it.
In other words, we'll wait till people get seriously injured or die..
..and then depending on the public backlash and amount of news coverage we might do something about it
So... Practical Engineering made a video about hydraulic jumps, and somehow even when this isn't in my field of study -at all-, I ended up here. Not like I'm complaining, in fact, I'm glad I watched this lol
Thanks for the education!
Excellent presentation. Explained one of my many curiosities. Thank you.
Just got an idea. How about making a self raising flip lip. Basically just long piece of plate steel (or structure with the same function) coated in plastic or paint, on moving axis and kept up by air filled barrels. That way you get constant depth of your flip lip no matter the height of the tail water.
This was great to see, it's always baffled me how these dams still exist.
Restricted access and public education would be the cheapest option, and would undoubtedly save some lives, but not all.
This gave me anxiety.
it gave me a useful bit of knowledge.
I love physics, nice video!
Fantastic work. Important lessons for people who come into contact with these conditions.
This is really well done. Very detailed, thorough, and clear. I felt that the part around 13:45 was particularly useful in pointing out indicators of dangerous hydraulics. Thank you for sharing this, and providing the opportunity for the boating community to educate ourselves.
“If someone try to float in this, it would not end well, it’s like trying to swim in foam”
Basketball says: hold my hoop
A basketball is a giant bubble of rubber filled with air. Of course it still floats.
Indeed, But people are not that boyant even with a life jacket on. What happens is they repeatedly are sucked under over and over, they can also drown on the surface because the water is so turbulent they just cannot get air. It’s called flush drowning.
@11:50 "His day is now ruined" Come on man, talk about euphemism. Ken "Yeah, so I, like, drowned, so i guess it kinda ruined my day."
Hahahah Amazing video btw! Congrats dude! You are a credit to human kind.
+Eduardo Bogosian It's mormon humor.
More like, it's everyone that minimizes death. Pilots "bend metal" or "auger in." Person crashes in an unsurvivable fireball; people say "That'll leave a mark." Rockets undergo "rapid unplanned disassembly."
A great video. Great contribution from BYU. Thanks very much.
I remember back in 2018 in my country (malaysia) we had a Case C scenario where it took 6 lives of the fire and rescue scuba team. They were on a body retrieval mission for a teen that died a day before but the most baffling thing about the incident is how the scuba team’s supervisor gave them the command to retrieve the body located at the low dam despite after a heavy rain and it was late at night which caused all 6 of the diving team to lose their lives.
there thousands of small weir dams around the world.. very very dangerous
The attempted recovery by the doomed untrained near the beginning is clear reason to leave it to the pros.
I had a modified flip lip one time when i was visiting Dallas. Good times. But seriously, this presentation is amazing. I don't know how i got here, but i watched the whole dam thing.
Excellent presentation! Thank you!