Oroville Dam, tallest in US overtopping

[StarCruiser]

Been watching this unfold over the last couple of days. Record rains in California have resulted in the Oroville reservoir reaching record levels and the spillway being opened to release water. The spillway has broken up and with the water still rising the emergency spillway has been reached and the neighbouring car park flooded. Residents downstream have been under an evacuation order for 36 hrs now. The water has now gone down low enough to stop overtopping the emergency spillway but there are more big storms on the way.
There's many videos on YouTube on this. Here's one for starters. The scale is immense. The water is 900 feet deep and the emergency spillway 100 feet high by 1000 feet long.
Hoping nobody is hurt and the worst doesn't happen…

Wouldn't you think this would be global news worthy…?

 

[froggy Steve]

Its been on Sky news, but not a lot - I think the water levels are dropping but storms are forecast for later this week - over 1000 peope are being kept away from their homes!

 

[StarCruiser]

I think it's more like 188000 now Steve. Some of the news seems to have been downplaying it.

 

[Rodger]

There was a piece on Spanish tv about this yesterday but a lot of Spanish people have family in the USA.
As an aside there is a little plaque in our town to remember that some of C Columbus's crew came from here.
However the situation does look serious, particularly with more storms on the way.

Regards,

 

[Shayne]

Thankfully plans for the dam were drew up in the 1950's by men with pen's who instinctively err on the side of caution so its not likely to collapse , had it been built in the digital age to perfect world cost effective milli spec computer generated plans i dread to think what might happen .

 

[clivehorridge]

Thankfully plans for the dam were drew up in the 1950's by men with pen's who instinctively err on the side of caution so its not likely to collapse , had it been built in the digital age to perfect world cost effective milli spec computer generated plans i dread to think what might happen .

Not sure I agree with that one Shayne, history is full of pompous business driven egotists or bloody minded designers saying it will never fail...

Still, let's hope it doesn't degrade too much more, it's already suffered major failure as you can see by the damage to the overflow area beneath the emergency spillway. The road is washed away, who knows what structural damage has been inflicted on the main mass of the dam and its foundation, and it's continuing to erode as we're watching it.

Fingers crossed it survives, it's a scary sight to see so much power. A total collapse would release energy on a par with an atomic bomb.

 

[StarCruiser]

I think that sums it up pretty well Clive. It's difficult to appreciate the sheer scale of this and the amount of water involved. There was apparently a call from environmental groups in 2005 that the spillways be brought up to modern safety standards but the then administration rejected it.

 

[clivehorridge]

Just watched a vid where 12 years ago, there were warnings of failures in the spillway...

It's a crude sketch, but it shows the potential for failure.

And on top of this, the dam is overflowing the emergency spillway which isn't at all designed to sustain such flows for long.

Sadly, it's a potential disaster to add to the long list in recent American history.

 

[Chas]

I think it's more like 188000 now Steve. Some of the news seems to have been downplaying it.

Its been on Sky news, but not a lot - I think the water levels are dropping but storms are forecast for later this week - over 1000 peope are being kept away from their homes!

One news programme I saw (can't remember if it was BBC or Sky) mentioned 30000 had been evacuated.

 

[Shayne]

Aye suppose your right Clive profits margins are usually the deciding factor then and now , it doesn't change my view that 300 year old houses are a damn site better built than the huts modern building techniques have given us .

 

[Bert]

This is the entrance to one of the spillways on the Hoover Dam........ the picture does not do the size of the thing justice........ this is where the water would 'spill over'...............

...and this is where it would flow down.... The Good Woman is looking down into it with trepidation.....

 

[clivehorridge]

Aye suppose your right Clive profits margins are usually the deciding factor then and now , it doesn't change my view that 300 year old houses are a damn site better built than the huts modern building techniques have given us .

I can't argue with that Shayne.

My second house (purchase) was a 280 year old stone cottage in West Wales, and the only means I had to estimate its age for mortgage purposes was to visit the local library and research the OS maps of the area, going back in 50 year steps till it wasn't there!

It was built by a shepherd (apparently) and was one of the first cottages built in what is now a 150 dwellings village.

It's still standing after all this time and the stone boulder foundations stop at about 2ft below the ground. It would never get planning permission by today's standards

 

[clivehorridge]

This is the story that prompted my post about the tendency for business pride to deny the inevitable...
William Mulholland...

 

[Towpack]

I reckon the main dam is a long way from breaching. It's the unprecedented and sustained heavy rainfall that's left the overflow unable to cope. This sort of thing seems to be getting more and more common the World over. Freak weather events becoming more frequent and simply overwhelming infrastructure that was never designed to cope with anything like it. Back in '07 we had a sustained deluge here in Yorkshire that left Ulley Reservoir in a dangerous condition resulting in the evacuation of 3 local villages and the closure of the M1. A large regional national grid substation was also under threat should the dam wall have breached so you can imagine the urgency of the situation and all this from a reservoir of mere bird bath proportions compared to the American dam.

 

[StarCruiser]

Quite TP, I remember that well. The Oroville bursting just doesn't bear thinking about. The word is that Earth dams that have breached are usually the result of the spillway failing. I'm not so sure in this case that there isn't a direct connection to the bedrock. Still, they don't evacuate without good reason.

 

[Chas]

Quite TP, I remember that well. The Oroville bursting just doesn't bear thinking about. The word is that Earth dams that have breached are usually the result of the spillway failing. I'm not so sure in this case that there isn't a direct connection to the bedrock. Still, they don't evacuate without good reason.

It's the erosion below the dam caused by the spillway damage

 

[StarCruiser]

Exactly Chas, this is what has them concerned. There are in fact three areas of concern. The complete failure of the main spillway from about 2/3 the way down. Erosion at the base of the emergency spillway as it was not designed for prolonged discharge of the magnitude that it has been taking. And a 30 foot hole that's appeared towards the car park end where the concrete meets the earth where the water got so high it flowed over the car park as well as the emergency spillway. Not good.

 

[frank rabbets]

Why did'nt the boy put his finger in it when it first started ?

 

[MarkW]

that'll be down to Trumps travel ban, the dutch boy was from a country Trump doesn't have business ties with so wasn't allowed into the US due to terrorism fears

 

[clivehorridge]

Of course, it's all Trump's fault... one way or another....