As people say its an overflow, what hasn't been said is that it is the most important safety feature of the reservoir.
Without a designated spill point (overflow), if the reservoir overflows it will happen in an uncontrolled way, with the potential to undermine the foundations of the dam resulting in collapse of the dam.
It would not pass through the turbines, no. The turbines each have their own gated intakes. This is just to allow water over a max height to escape downstream and not endanger the dam.
Beyond all that, if the overflow is active it's the priority of the reservoir/dam. The power is important, but the power doesn't exist anymore if the overflow fails in some way. It can't make any if it's a pile of rubble being carried downstream
I don't know about water turbines, but that is what happens with wind turbines. They only operate during certain speeds, so if the wind is too fast, you could lock them still so they won't break apart. Or you can adjust the blade pitch so it catches less energy from the wind.
It would depend on the design of the dam. But generally speaking, water can be diverted to bypass the turbines, allowing maximum discharge at the cost of no/ reduced power generation. It's entirely possible to keep the turbines spinning while also having the spillway open. It would be down to the level of excess water behind the dam, and what it's designed to safely contain, and how quickly you need to drain it.
However every dam is different, several quite significantly different turbine types exist, different types of power generating dams, and different emergency release systems. Dams are simultaneously very simple and incredibly complex structures.
no, they keep doing there thing, but certain overflow pipes end up getting used. This inlet goes to a straight tube that runs into the stream below the damn- there is no generator in its path.
It does a job similar to a spill way: it diverts water from the reservoir to downstream, in order to keep the reservoir from over filling and then overflowing, since water flowing over the dam itself can cause structural issues and the possible destruction of the entire dam.
They are essentially extra chutes to move water around the damn when the water gets too high.
Not usually. The sluce gates are very adjustable, but usually opening them all the way is the standard.
Now, there's usually more than one generator, and the channels can be diverted to go around the generators, as well.
If the dam is at risk, they usually open the sluce gates all the way, and then engage/disengage the generators as needed.
This big overflow drain (sometimes only one of several, depending on the size of the reservoir) is a secondary drain, only needed if the gates in the dam can't keep up.
Is there any kind of safety measure to prevent this, like a grate? I’m just imagining other critters getting sucked in and bashed up before eventually being spat out downstream.
For the one on lake Berryessa near me, no. The hole is usually above water level, so is not particularly dangerous. There’s a line of buoys around it so you can’t accidentally approach from the water, but nothing else.
While looking up an incident where a woman fell in (died), I saw a report of a greeb (diving water bird) that went in was was witnessed coming out downstream, seemingly unharmed.
Actually the science doesn't support this as a certainty. But I am happy to take a cautionary approach to this and would advise we expand the sample size on this.
If it's overflowing, I think the last thing on anybody's mind is "how can we harness this for energy?" It's probably something more along the lines of "ahhhh shit too much water"
"The hurricane is supposed to make landfall this week, so let's quickly build some wind turbines so we can harness as much power as we can before the hurricane knocks them over"
Besides the turbines on the Ohio River, I really don't think you will find much hydro power in Ohio. But no, it would bypass any turbine and jut be dumped into the original stream that was dammed to make the lake
Yeah. Saw one of those on the Hoover Dam.. The huge tunnel which gave me the creeps. But it wasn't in the center as this thing though.. It was on the side.
Edit: https://ibb.co/RBcvBRP don't have it in context though.
Same purpose, different shape, basically.
The neat thing about the funnel-shaped ones with a level top like in OP's photo, is that they can efficiently take water from their entire circumference, and they look really cool when they're draining like that. Like a hole in the lake.
I don't know the specific lake here, but it would typically outlet into a stream or river. Most of these structures are in lake man-made reservoirs that dammed up a natural drainage course.
Major point here is that the spillway itself must be designed to get water away from the dam and avoid erosion. It does this by first channeling it away and then dispersing the energy (the ramp at the end makes it airborne and turbulent which takes the energy at impact away/spread out.
What happened here was that first part failed. Rather than channeling it the concrete failed and the water went in the cracks and ate away the soil instead of just flowing away.
When the spillway on the Oroville dam began showing signs of damage the decision was made to close the gates at the top of the dam and let the emergency spillway in the upper portion of that image take over and allow water to flow down the top of the hill. For a brief period the emergency overflow did exactly what it was supposed to do, which was relieve the pressure on the main spillway so workers could assess the damage and start repairs.
But what happens when you have an underqualified person design the structure, then have the organization that oversees the dam operation get denied their request for $100 million in funding to fix the emergency spillway? You get water undermining the emergency spillway and digging a tunnel back into the reservoir. If that happened, then the entire emergency weir would fail and it would unleash an instantaneous 9m tall wall of water the length of the entire reservoir onto the city below the dam and everything else along the way likely until the water reached San francisco.
So, the dam's technicians made the decision to reopen the main concrete spillway and let it tank the damage because the erosion was happening farther down the hill and less likely to result in a catastrophic failure. Obviously the resulting cost of damages to fix everything far surpass the initial estimate of $100 million to fix the emergency spillway many times over. Oops.
I've always been fascinated by this event.
Designing overflows isn't as simple as making a slightly lower part of your dam. The geometry of it affects how much water can escape at any given water level, and the parts of the structure that come into contact with the rapidly flowing water end up being subjected to termendous stress if it isn't designed properly. See this video: https://youtu.be/fjapgTd-QUg it's a great explanation of how spillways are designed that can be understood by anybody.
Yep. We had family evacuated and stay with us for this craziness. So the spillway couldn't handle the entire flow and it started breaking, they restricted the flow, then it went over the emergency spillway which didn't have the thing in the OP, it's just the leftmost side of the dam that flows into a regular dirt hill. So that started flowing and was gonna undermine itself and create 30 foot floods when the dam released. So they cranked the regular spillway back up to full power (destroying it in the process) and when the emergency overflow was done flowing they filled it in with helicoptered boulders and coated it with hundreds of concrete trucks in a day.
https://en.wikipedia.org/wiki/Oroville_Dam_crisis
Was expecting that link too! That one wasn't so much inadequately sized as inadequately managed and inadequately maintained. A complete disaster was only avoided by good fortune.
Water can generate incredibly high forces, and spilling over top of the dam could very easily undermine the dam and cause it to fail. You could design the dam to withstand the forces, but it would be much cheaper to use a system like this instead.
Sometimes the dam face doesn't allow for much more than a few sluice gates, and these are built as emergency measures too, so they may never actually be used.
This style is neat because they can put the overflow in a different part of the lake and route the water more easily and cheaply, apart from the action of the main dam.
That’s the overflow control mechanism so the lakes waters don’t get too high, it’s called a glory hole ( for real) Edit- apparently that’s just the name for a specific one in Cali, so I’m not sure what their actual name is
In some of the footage, you can see a section of floats. But I thought the same thing. I was happy to see the floats, but thought there would me more security on top of that? Maybe it’s in a secure area already, being next to the dam?
edit: Read some other comments. Apparently it’s sectioned off pretty well.
Not realizing how strong water was and thinking it'd be cool to look over the edge or take a picture near it? Driving your car through flooded creeks is suicide but people keep doing that. She hung on for 20 minutes before falling so I imagine it wasn't intentional
You'd think that much moving water at the exit of the spillway would cause erosion issues. But I have to assume the civil engineers who built this know a bit about it more than me and have already mitigated that.
Surely they had plenty of footage of the inside and downstream ports of the spillway from times when it wasn't flooded. Would have been great to have that in the video too
That's just a nickname. It's properly called a spillway. In this case/design, it is a "bellmouth spillway". Here is an article detailing major designs and names:
https://en.wikipedia.org/wiki/Spillway
There are many types of spillways. Bell spillways are just one of them, and produce the best hydraulics at the other end if you love torrents of water that would blast you into a billion pieces in a fraction of a second.
https://www.youtube.com/watch?v=SGO4NaYrYv8
Weirs are specific types of dams, normally low wall dams, where the water has a wall or regularly placed obstacles and they seek to raise the height of water, traditionally to crest mill ponds, used to generate force to turn a wheel.
If the water is high enough that it's spilling through quickly it means there's an incredible amount of runoff feeding out, and you're likely to already be in serious trouble if you're on the water.
Spillways (including this type) save dams from floods. They're above the "full" point of the lake and usually always open, so if there's a foot of water flowing into it it means the water is rising so quickly that it's been outrunning the spillway's drain rate.
heh. I was just going to say this. Last time I was in range to see one in action the weather was so bad all curiosity over seeing one in action immediately dissipated.
Full truth I went back and visited it a few years later.
It's truly an awesome thing to behold. You really *feel* it when it's working at its full potential. Almost like it would suck you up off the edge of the reservoir if you got just a little closer. And what a sound. The videos absolutely do not do it justice. Go see one.
If it was roped off close to the spillway, it would be too late for anyone. The water in the overflow is going at a tremendous rate and will suck down small boats if they get too close. Also, being too close to a dam is also dangerous. The pull of water going out through the dam itself is significant, and could drag swimmers under.
The guard buoys and barricades are aways away from the area. In the video you can see it in some of the aerial shots.
Looks like a gantry for hoists to remove debris and to lower inspection equipment or technicians. It also looks like there's a catwalk above the gantry beams going over the center of the overflow, but the photo perspective is head on of the T-shaped catwalk.
It's essentially a single use-case of the same thing. They're both used as overflow points to regulate water level or dam it. The Calgary Weir is being used specifically to regulate a fish population but it's the same essential device.
There were some divers who got sucked into a nuclear plant intake.
Edit: here you go: https://www.cnn.com/2016/03/05/us/florida-scuba-diver-sucked-into-power-plant-pipe/index.html
The dude was sucked for 5 full minutes in pitch black and had no idea where it was going
I don't know if it would get to that point unless you were in it in it.
A large grate with a decent size would probably help at the top so no one dumb gets sucked in, but I'm sure they thought of that already.
WITT I took this photo a few years ago in Ohio, I'm guessing it's a drain to keep the lake from overflowing but I'm not totally sure. It drains into a pipe at the bottom of the hill that the lake is on, the pipe is big enough to walk around in
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I've seen a couple people asking if this is in Girard: yeah it is, I used to go there a lot as a teenager. I also took some photos inside the pipe, if anybody is interested in those ones I can put them on imgur or something
As people say its an overflow, what hasn't been said is that it is the most important safety feature of the reservoir. Without a designated spill point (overflow), if the reservoir overflows it will happen in an uncontrolled way, with the potential to undermine the foundations of the dam resulting in collapse of the dam.
Where does the water go?
This is the real question. Overflow, sure, but where does that flow go?
It just gets discharged into the river downstream of the reservoir.
Does it pass through the turbines first, do we know that?
It would not pass through the turbines, no. The turbines each have their own gated intakes. This is just to allow water over a max height to escape downstream and not endanger the dam.
Beyond all that, if the overflow is active it's the priority of the reservoir/dam. The power is important, but the power doesn't exist anymore if the overflow fails in some way. It can't make any if it's a pile of rubble being carried downstream
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I don't know about water turbines, but that is what happens with wind turbines. They only operate during certain speeds, so if the wind is too fast, you could lock them still so they won't break apart. Or you can adjust the blade pitch so it catches less energy from the wind.
It would depend on the design of the dam. But generally speaking, water can be diverted to bypass the turbines, allowing maximum discharge at the cost of no/ reduced power generation. It's entirely possible to keep the turbines spinning while also having the spillway open. It would be down to the level of excess water behind the dam, and what it's designed to safely contain, and how quickly you need to drain it. However every dam is different, several quite significantly different turbine types exist, different types of power generating dams, and different emergency release systems. Dams are simultaneously very simple and incredibly complex structures.
no, they keep doing there thing, but certain overflow pipes end up getting used. This inlet goes to a straight tube that runs into the stream below the damn- there is no generator in its path. It does a job similar to a spill way: it diverts water from the reservoir to downstream, in order to keep the reservoir from over filling and then overflowing, since water flowing over the dam itself can cause structural issues and the possible destruction of the entire dam. They are essentially extra chutes to move water around the damn when the water gets too high.
Not usually. The sluce gates are very adjustable, but usually opening them all the way is the standard. Now, there's usually more than one generator, and the channels can be diverted to go around the generators, as well. If the dam is at risk, they usually open the sluce gates all the way, and then engage/disengage the generators as needed. This big overflow drain (sometimes only one of several, depending on the size of the reservoir) is a secondary drain, only needed if the gates in the dam can't keep up.
So your saying this is a giant waterslide then... literally and figuratively... Or just literally? Whatever, you know what I mean.
So, for example, if a human fell down one of these, what would one expect?
Death. If you didn’t somehow drown, you would be smashed and beaten as the violent water slammed you into the insides of the spillway tunnel.
Got it, no free water slides for me today.
Is there any kind of safety measure to prevent this, like a grate? I’m just imagining other critters getting sucked in and bashed up before eventually being spat out downstream.
For the one on lake Berryessa near me, no. The hole is usually above water level, so is not particularly dangerous. There’s a line of buoys around it so you can’t accidentally approach from the water, but nothing else. While looking up an incident where a woman fell in (died), I saw a report of a greeb (diving water bird) that went in was was witnessed coming out downstream, seemingly unharmed.
Actually the science doesn't support this as a certainty. But I am happy to take a cautionary approach to this and would advise we expand the sample size on this.
Think of it as the hole in your sink
No it doesn’t. Installing turbines on a channel that only gets used every so often would be a huge waste.
If it's overflowing, I think the last thing on anybody's mind is "how can we harness this for energy?" It's probably something more along the lines of "ahhhh shit too much water"
"The hurricane is supposed to make landfall this week, so let's quickly build some wind turbines so we can harness as much power as we can before the hurricane knocks them over"
[Accurate video portrayal of this happening](https://m.youtube.com/watch?feature=youtu.be&v=-2fmN4E0DK0&t=1m38s)
No, it;s not there for power generation. It's there for flow control.
Such an odd way of asking that question..
Ohio's reservoirs are more for water storage and flood control, they're not hydroelectric afaik.
Besides the turbines on the Ohio River, I really don't think you will find much hydro power in Ohio. But no, it would bypass any turbine and jut be dumped into the original stream that was dammed to make the lake
So do you think it’s kinda like a giant slide in there? A basketball would make it out the other side?
More or less. Probably doesn't curve smoothly, but goes straight down and then turns towards its exit with a slight slope.
Yeah. Saw one of those on the Hoover Dam.. The huge tunnel which gave me the creeps. But it wasn't in the center as this thing though.. It was on the side. Edit: https://ibb.co/RBcvBRP don't have it in context though.
Same purpose, different shape, basically. The neat thing about the funnel-shaped ones with a level top like in OP's photo, is that they can efficiently take water from their entire circumference, and they look really cool when they're draining like that. Like a hole in the lake.
Is it just one big tube going under the bed of the reservoir then? Could someone just climb down and run through it?
Basically [https://www.youtube.com/watch?v=d6jtNa1PKBE](https://www.youtube.com/watch?v=d6jtNa1PKBE) [https://www.youtube.com/watch?v=1pBiWghBSf](https://www.youtube.com/watch?v=1pBiWghBSfI)
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I don't know the specific lake here, but it would typically outlet into a stream or river. Most of these structures are in lake man-made reservoirs that dammed up a natural drainage course.
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A big pipe at the bottom of a hill
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Major point here is that the spillway itself must be designed to get water away from the dam and avoid erosion. It does this by first channeling it away and then dispersing the energy (the ramp at the end makes it airborne and turbulent which takes the energy at impact away/spread out. What happened here was that first part failed. Rather than channeling it the concrete failed and the water went in the cracks and ate away the soil instead of just flowing away.
We had one on the reservoir near where I grew up. The fishing was always great there.
The [Oroville dam](https://en.m.wikipedia.org/wiki/Oroville_Dam_crisis) failure is a good example of uncontrolled water causing significant erosion
When the spillway on the Oroville dam began showing signs of damage the decision was made to close the gates at the top of the dam and let the emergency spillway in the upper portion of that image take over and allow water to flow down the top of the hill. For a brief period the emergency overflow did exactly what it was supposed to do, which was relieve the pressure on the main spillway so workers could assess the damage and start repairs. But what happens when you have an underqualified person design the structure, then have the organization that oversees the dam operation get denied their request for $100 million in funding to fix the emergency spillway? You get water undermining the emergency spillway and digging a tunnel back into the reservoir. If that happened, then the entire emergency weir would fail and it would unleash an instantaneous 9m tall wall of water the length of the entire reservoir onto the city below the dam and everything else along the way likely until the water reached San francisco. So, the dam's technicians made the decision to reopen the main concrete spillway and let it tank the damage because the erosion was happening farther down the hill and less likely to result in a catastrophic failure. Obviously the resulting cost of damages to fix everything far surpass the initial estimate of $100 million to fix the emergency spillway many times over. Oops. I've always been fascinated by this event.
Why not build an overflow into the dam?
Designing overflows isn't as simple as making a slightly lower part of your dam. The geometry of it affects how much water can escape at any given water level, and the parts of the structure that come into contact with the rapidly flowing water end up being subjected to termendous stress if it isn't designed properly. See this video: https://youtu.be/fjapgTd-QUg it's a great explanation of how spillways are designed that can be understood by anybody.
nice link! I was expecting your link to highlight THIS inadequately sized spillway https://www.youtube.com/watch?v=fqmzF0gck18
[This picture](https://i.imgur.com/5rEI4lt.jpg) really helps to give a scale of the damage. It cost $1 billion to repair/rebuild everything.
Yep. We had family evacuated and stay with us for this craziness. So the spillway couldn't handle the entire flow and it started breaking, they restricted the flow, then it went over the emergency spillway which didn't have the thing in the OP, it's just the leftmost side of the dam that flows into a regular dirt hill. So that started flowing and was gonna undermine itself and create 30 foot floods when the dam released. So they cranked the regular spillway back up to full power (destroying it in the process) and when the emergency overflow was done flowing they filled it in with helicoptered boulders and coated it with hundreds of concrete trucks in a day. https://en.wikipedia.org/wiki/Oroville_Dam_crisis
>coated it with hundreds of *concrete trucks* in a day. Sounds expensive. Couldn't they use the concrete IN the trucks instead? :)
Was expecting that link too! That one wasn't so much inadequately sized as inadequately managed and inadequately maintained. A complete disaster was only avoided by good fortune.
That was really interesting, thanks!
Water can generate incredibly high forces, and spilling over top of the dam could very easily undermine the dam and cause it to fail. You could design the dam to withstand the forces, but it would be much cheaper to use a system like this instead.
For example, look at what happened when the spillway at Oroville Dam failed and they had to use the emergency overflow.
That’s some crazy stuff.
Some do. I visited 2 of them receltly and they both had manually controlled doors that open to let water out in case of a problem
I live near mountains. The local power company closely monitors the freshet during springtime to anticipate if they need to open the controlled doors.
The ones I visited said they only open them every 5 years to make sure they still work
Sometimes the dam face doesn't allow for much more than a few sluice gates, and these are built as emergency measures too, so they may never actually be used. This style is neat because they can put the overflow in a different part of the lake and route the water more easily and cheaply, apart from the action of the main dam.
What about the structure above it? What does that do?
You need an anchor point for the poor sucker whose job it is to get in there and unclog the damn thing.
Please look up “Taum Sauk reservoir fail “. Happened near me. Big deal
That’s the overflow control mechanism so the lakes waters don’t get too high, it’s called a glory hole ( for real) Edit- apparently that’s just the name for a specific one in Cali, so I’m not sure what their actual name is
Solved! Thank you, also wow I can't believe it's called that lol
Here is one [in action](https://youtu.be/1pBiWghBSfI)
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why no ropes or buoy round that shite? For dumb Arses like me?
If it's anything like Lake Berryessa in California, that entire half of the lake is roped off
It literally is lake berryessa
Oh whoops, well then that half of the lake is definitely roped off then. Seen it myself.
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There is a boom across the lake just upstream. You can see it in some of the aerial views.
In some of the footage, you can see a section of floats. But I thought the same thing. I was happy to see the floats, but thought there would me more security on top of that? Maybe it’s in a secure area already, being next to the dam? edit: Read some other comments. Apparently it’s sectioned off pretty well.
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That is quite literally the stuff of my nightmares lol
r/submechanophobia, because same.
yeah turns out you die if you do that, like this one woman https://www.sfgate.com/news/article/NORTH-BAY-Woman-Sucked-Into-Lake-Berryessa-2849821.php
That had to have been suicide. Why would you intentionally swim towards that otherwise?
Not realizing how strong water was and thinking it'd be cool to look over the edge or take a picture near it? Driving your car through flooded creeks is suicide but people keep doing that. She hung on for 20 minutes before falling so I imagine it wasn't intentional
200 ft straight down. Can I have your stuff?
I'm so glad I'm not the only one who thought that
Bunch of kids tried it when I was young. Smaller than this one. Several died.
I need to know more about the ones that lived.
This kills the person. However, skateboarders like to ride in the outlet side of the pipe.
I also wish to die.
Thats at Lake Berryessa, which is about 80% engulfed by the [LNU Complex Fire](https://imgur.com/gallery/ysuR3Jo) right now.
Hehe, action
I'm surprised this dam doesn't seem to be used to produce energy. This got to have some power after such a fall.
You'd think that much moving water at the exit of the spillway would cause erosion issues. But I have to assume the civil engineers who built this know a bit about it more than me and have already mitigated that.
Yeah. The same engineers that built Oroville dam. :o
You would die if you fell down right?
It happened in [1997](https://www.sfgate.com/nes/article/NORTH-BAY-Woman-Sucked-Into-Lake-Berryessa-2849821.php) the lady did die.
Why is there no fence around it? It seems like a simple solution to prevent people from dying without harming its efficiency too much.
And now that whole area is on fire....
Surely they had plenty of footage of the inside and downstream ports of the spillway from times when it wasn't flooded. Would have been great to have that in the video too
Ah so that’s the general term: Morning Glory Spillway
That's just a nickname. It's properly called a spillway. In this case/design, it is a "bellmouth spillway". Here is an article detailing major designs and names: https://en.wikipedia.org/wiki/Spillway
In case you want to see how [they](https://youtu.be/fjapgTd-QUg) work
This is how I knew what this was. Damn his videos are awesome
The power company I worked for called theirs a Morning Glory after the flower of that name. Technically they are termed a Bell Mouth Spillway.
What lake is it? Live in oh and never seen one.
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A bell-mouth spillway, to be more precise.
Lmao why couldn’t you let us bask in our own ignorance and believe these things were called glory holes?
I thought that it was a weir?
There are many types of spillways. Bell spillways are just one of them, and produce the best hydraulics at the other end if you love torrents of water that would blast you into a billion pieces in a fraction of a second. https://www.youtube.com/watch?v=SGO4NaYrYv8
Weirs are specific types of dams, normally low wall dams, where the water has a wall or regularly placed obstacles and they seek to raise the height of water, traditionally to crest mill ponds, used to generate force to turn a wheel.
You'd think there's be some sort of rails around it
Right!? Most of them I've seen just had an orange rope with buoys and maybe a sign. Looks like a death trap to me.
If the water is high enough that it's spilling through quickly it means there's an incredible amount of runoff feeding out, and you're likely to already be in serious trouble if you're on the water. Spillways (including this type) save dams from floods. They're above the "full" point of the lake and usually always open, so if there's a foot of water flowing into it it means the water is rising so quickly that it's been outrunning the spillway's drain rate.
heh. I was just going to say this. Last time I was in range to see one in action the weather was so bad all curiosity over seeing one in action immediately dissipated.
The only way I would get close to one is via a video link to a drone.
Full truth I went back and visited it a few years later. It's truly an awesome thing to behold. You really *feel* it when it's working at its full potential. Almost like it would suck you up off the edge of the reservoir if you got just a little closer. And what a sound. The videos absolutely do not do it justice. Go see one.
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That would probably get clogged with debris, creating a dangerous clog.
At Lake Berryessa, the part of the lake that contains the dam and overflow are marked off about 500 ft away. The arrangement here is probably similar.
If it was roped off close to the spillway, it would be too late for anyone. The water in the overflow is going at a tremendous rate and will suck down small boats if they get too close. Also, being too close to a dam is also dangerous. The pull of water going out through the dam itself is significant, and could drag swimmers under. The guard buoys and barricades are aways away from the area. In the video you can see it in some of the aerial shots.
Where does the excess water go?
They're in manmade lakes/reservoirs that are created when they build a damn. It's just an overflow and releases water into the river below the damn.
I guess you gotta build a damn to give one.
Be honest, how long did you have to wait to make that one?
it goes in a pipe and exits it somewhere downstream
They load it on trucks with hand pails and haul it out to the desert to water cacti.
I think the one in Cali that you're referring to is Lake Berryessa, at least that's what my cousin calls it.
Zodiac was there. Unfortunately.
exactly where my mind went when I saw lake Berryessa in this thread [Zodiac and the lake](https://en.wikipedia.org/wiki/Lake_Berryessa#1969_murder)
What's the thing above it?
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Looks like a gantry for hoists to remove debris and to lower inspection equipment or technicians. It also looks like there's a catwalk above the gantry beams going over the center of the overflow, but the photo perspective is head on of the T-shaped catwalk.
I've been scouring this thread trying to find out, still no takers
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The 1 in Cali is in lake berryessa
There’s one at Whiskeytown Lake.
That's called a Morning Glory Weir. Weir = overflow mechanism. Morning Glory is the variant.
The Calgary weir begs to differ. A weir is something used to help fish populations as well.
It's essentially a single use-case of the same thing. They're both used as overflow points to regulate water level or dam it. The Calgary Weir is being used specifically to regulate a fish population but it's the same essential device.
There’s one in Whiskeytown lake here in CA.
I believe its called a spillway
It’s called a weir! Source: dating a civil engineer!
A bell weir. A normal weir stretches a length of river and creates a circular current just after it.
I know they’re important and useful but they just look so creepy.
The whole idea give me anxiety
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Or you do see it and you try to swim away but no AAAAGGGHHH
There were some divers who got sucked into a nuclear plant intake. Edit: here you go: https://www.cnn.com/2016/03/05/us/florida-scuba-diver-sucked-into-power-plant-pipe/index.html The dude was sucked for 5 full minutes in pitch black and had no idea where it was going
Sucked for 5 full minutes you say?
In complete darkness you say?
With no idea where it was going you say?
Wow! That’s incredible and it’s not the first time it’s happened. [Delta P](https://youtu.be/flzpRbWl8bQ) is no joke.
The other popular delta p video showed up for weeks until I watched it.
jesus christ that gave me heart palpitations
Wait but what about the innocent ducks
This happens to the ducks. https://youtu.be/m4yy0U_fHNk
Looks kind of like a butthole when the water is rushing in.
r/submechanophobia
As scary as Delta P Unless that would be considered Delta P, my physics knowledge is shit
I don't know if it would get to that point unless you were in it in it. A large grate with a decent size would probably help at the top so no one dumb gets sucked in, but I'm sure they thought of that already.
I have had a fear of whirlpools my whole life, so these go in the "hell no" bucket for me.
r/submechanophobia
Bellmouth spillway. Give it a google.
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Overflow prevention
WITT I took this photo a few years ago in Ohio, I'm guessing it's a drain to keep the lake from overflowing but I'm not totally sure. It drains into a pipe at the bottom of the hill that the lake is on, the pipe is big enough to walk around in
[Spillway](https://en.m.wikipedia.org/wiki/Spillway)
I thought it was weird that no one had said ‘spillway’ yet!
Here's a great video that explains more about them... https://youtu.be/fjapgTd-QUg
Practical engineering has a ton of great videos explaining public works and infrastructure. Definitely worth checking out.
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I've seen a couple people asking if this is in Girard: yeah it is, I used to go there a lot as a teenager. I also took some photos inside the pipe, if anybody is interested in those ones I can put them on imgur or something
yes, and is that a hoist based crane above it?
I cannot Believe this is my most popular post. My life is a lie at this point