Have you ever seen a bell-mouth spillway? (aka a “Glory Hole”)

Miscellaneous and Personal Stuff I Must Share
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Dam! Today was my first one. It is pretty cool!

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https://i.imgur.com/MAsD6pK.mp4

Lake Berryessa’s water level is high enough that water is flowing through the spillway for Monticello Dam. This type of spillway is a bell-mouth spillway. When empty, a bell-mouth spillway looks like an upside down bell. Bell-mouth spillways are also called morning glory (after the flower), glory hole, or shaft spillways.

The DD coordinates for this glory hole spillway are 38.5122, -122.1049. Punch those numbers into the map (and include the comma, space, and minus sign) and the map will take you right to it.

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Monticello Dam, on the border of Yolo County and Solano County, is in such a narrow canyon that a traditional spillway would have been prohibitive to build. This glory hole spillway is 72’ in diameter and is at the east end of Lake Berryessa.

Lake Berryessa’s water level is currently 8” above the glory hole (as per ➜ https://www.lakeBerryessaNews.com ■ ). The glory hole has been spilling for two months ago, since 04 February. It has spilled before, in prior years. The dam and spillway were built in 1957.

Some ducks were swimming near it. I’m pretty sure they’ve learned to stay away from it!

Watching the water spill down it, and hearing it, it had a somewhat mesmerizing quality to it.

The rest of my pics and videos here —

[Album] Pretty cool! Have you ever seen a bell-mouth spillway?
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There are some others:

∘ Montana — Glory hole ▲ 48.3434, -114.0125, in Hungry Horse Reservoir; at Hungry Horse Dam in northwest Montana is the highest one in the world (as per wiki) at 3,560’ above sea level
∘ Australia — Glory hole ▲ -36.30585, 148.3159, in Geehi Reservoir; at Geehi Dam, in New South Wales, Australia; it is the widest at 105’
∘ Portugal — Glory Hole ▲ 40.3639, -7.6109 in Covão dos Conchos reservoir in Portugal is built to look like a natural formation
∘ Wales — Glory hole ▲ 51.798, -3.3656 in southern Wales; Pontsticill Reservoir (or, Cronfa Ddŵr Pontsticill)

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The one in Lake Berryessa is the only one I have ever seen. I saw it on two occasions while I was a student at UC Davis. The fist time I saw it, I was completely fasicnated by it and just stared at it for quite some time.

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The ones at Hoover/Boulder Dam on the Colorado river near Las Vegas aren’t the vertical pipe to Hell like that. So they may not qualify for the OP. But I’ve seen them dry and seen them spilling. They will probably never spill again in my lifetime, if ever.

Dry or wet, it’s a frankly horrifying sight; this gigantic concrete maw like an enormous trombone mouth that leads down at a stupid-steep angle to the very depths of the Earth. The sensation of being drawn towards a point-of-no-return crisis is palpable.

This isn’t the best result set, but you’ll be able to pick some nuggets out of the dross: Boulder Dam Spillway Mouth - Google Image Search

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Owyhee Dam in eastern Oregon has one. (That dam was built before the Hoover Dam as a sort of prototype)

There’s a couple cool videos linked at the end of this article:

Spent a lot of time there as a kid. On our way up the lake we’d always stop and walk out on the observation platform where you could look down in it and feel the mist rising off. The mist felt good. It gets hotter than hell in that high desert. But looking down into that glory hole, awesome though it was, would always freak out my little mind a bit. I couldn’t help but imagine being on an inner tube, trying to paddle away, but being pulled ever closer to that big sucking hole…

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Not in person; just in the form of memes. Like so:

In fact until it was explained on another forum years ago I thought the image was some photomanipulation trick, not real. It does look unreal.

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Too bad they couldn’t capture the giant snake monster in the same frame.

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Be careful Googling “Glory Hole”. Just sayin…

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I first saw one of these on a road trip, coincidentally just a few days after I learned about delta-p.

A glory hole won’t cause a delta-p situation, but it was just one more thing in the growing list of “scary things water can do to you”. I did not much fancy the idea of getting sucked into a watery death tube of any diameter.

That was not an easy week to sleep through…

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Very cool. The Owyhee Dam has been marked on my map as an interesting dam to go to and see, for years now. I must’ve marked it after Aug 2017 because that’s the last time I was up in that area (for the solar eclipse; I was in Midvale, ID for that). Of course it would be more interesting to see that ring spillway when the water is flowing into it.

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That picture is of the same place I was earlier today, Lake Berryessa.

Yes it does look unreal. ‘Oh shit’ is right!

There were some ducks swimming close to the glory hole today. i was watching them, thinking… I suppose that in the past 60+ years that the glory hole has been there, that the ducks have learned to not get too close to it. But I imagine that a quick-thinking duck, should one get sucked in, would be able to fly away before going down into it.

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There was one near my home town in Zimbabwe, where we occasionally went water-skiing. Us kids would walk up the pipe from the egress and play in the circular waterfall.

This, naturally led to a large scar under my chin, after I slipped… waited for the bleeding to stop, and never told my mother what we were up to.

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Dillon reservoir in Summit County Colorado has one.

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Interesting. I’ve morbidly wondered in the past what would happen if one fell into a bell-mouth spillway like the one in the OP. It sure looks like it would be pretty darn fatal, but, depending on the diameter of the pipe once the funnel narrows, length of transit, height of exit and depth of water you fall into, maybe it wouldn’t be so bad. Almost like a waterslide at Action Park! That’s a lot of ‘dependings’ though. Sounds like your spillway was small enough, but wide enough in diameter, to not be fatal.

I did find while googling just now that there’s been at least one spillway death, at the very same Glory Hole at Lake Berryessa in the OP. Sounds awful-- the woman managed to cling to the rim for 20 minutes before she was swept in. So, don’t try it, kids.

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There’s one of these at the dam at Grovers Mill in West Windsor, New Jersey.

And if that sounds familiar – yes, this is the place where the Martian cylinder landed in the infamous Orson Welles 1938 Halloween War of the Worlds broadcast. There’s a monument there now, erected on the 50th anniversary of the event. The Mill building is still there, and so is the odd water tower that was supposedly shot at because someone thought it was a Martian tripod.

Never heard it called a “Glory Hole” before. That’s playing with fire.

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Also been to Owyhee dam several times and seen its glory hole. My mother’s family went to see the dam right after it was filled for the first time. Got a pic of the hole from its early operation.

The snowmelt has just begun and the reservoir is fairly full. The glory hole is going to see a lot of use. (They’ve added extra electrical turbines to the dam but those will only take care of some of the extra water.)

Fun fact: the Owyhee reservoir is the largest body of water completely inside the state of Oregon. Yet not many Oregonians know about it let alone have seen it. I guess Dopers are a different class of people.

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Yeah I was getting some unintended results when googling ‘Zimbabwe glory hole’ just now. Even when googling ‘Zimbabwe glory hole spillway’ I wasn’t getting what I wanted.

People at Google might be thinking that I’m lookin’ for love in all the wrong places.

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I went to Lake Berryessa a few years ago to see this. The water level was just barely enough to be flowing into the spillway so it wasn’t as cool looking as I had hoped. As I remember it was kind of tough to get a good picture from the side of the road…the drone shots are the way to go.

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What’s that platform type thingy on the edge of it ?

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I assume it’s trash that got sucked against the ring.