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Oroville Spillway Failure


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#1 john

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Posted 09 February 2017 - 04:36 PM

Is anyone worried about this? It looks bad and is only getting worse. 



#2 (Folsom Trails)

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Posted 09 February 2017 - 04:54 PM

Admittedly it looks bad but in all reports I've heard they seem very confident it had nothing to do with the dam itself. Right now the problem is releasing as it is well over 90% capacity. Hopefully they know what they're talking about. That reservoir is either the largest or one of the largest in the state.

#3 nomad

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Posted 09 February 2017 - 07:06 PM

"They seem confident..." aka...run for the hills!



#4 Who_Do_You_Trust

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Posted 09 February 2017 - 07:38 PM

The spillway failure is far from the dam...100 yards?  I believe what they are trying to do is minimize the damage to minimize repair costs and time.    If they let water run down the spillway, it will erode more of it, but only the areas below the current failure.  Right now the repair costs will probably be a couple million $.  If they let the water flow and it takes out the rest of the spillway below the current failure, the repair costs will probably be several $10's of millions. No matter how bad it gets, they've got to get it fixed next summer to prepare for a similar winter next year. 



#5 Chris

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Posted 09 February 2017 - 07:48 PM

Yes, very worried.  That spillway is toast and they still have to use it.   Built a long time ago, did not take "cavitation" into account on this one.   I think inflows are about 180,000 cubic feet per second and outflows are at about 40,000 cfps at best.   Do the math and that thing will overtop the emergency spillway in 2-3 days.  Buy stock in the local concrete contractor up there as that will be a 2-3 year job for sure.   Hopefully they put "steps" in the spillway like the new one at Folsom Lake has.   Stops cavitation with aeration.....


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#6 Chris

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Posted 09 February 2017 - 07:54 PM

And this...........

 

https://www.metabunk...-failure.t8381/


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#7 nomad

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Posted 10 February 2017 - 08:50 AM

Can anyone explain what the "Emergency spillway" there is exactly? All the diagrams I have seen just show a red squiggly line to the left of the spillway that goes down the hillside and through trees. There appears to be no structure for the water to flow. And how do they open this? Is there another gate that feeds this? It doesn't appear so. 

 

And if they open this emergency spillway tons of hillside and trees will be swept away and flushed into the rivers. 

 

What a mess. These DWR guys on tv all look confused, like this is the first time they've had to deal with a real emergency. And all of their hard hats and reflective vests look like it's the first time they have been used!



#8 Carl G

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Posted 10 February 2017 - 09:03 AM

It looks like a last-chance spillway to prevent the dam from being overtopped.  It is built a bit lower than the dam.

 

My question is with a big, gaping hole in the spillway, why would you "test" it by sending more water down.  What did they think would happen?  The hole would magically fill itself?



#9 (Folsom Trails)

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Posted 10 February 2017 - 09:37 AM

I heard releasing wAs of utmost importance right now. They said that beneath the spillway it is solid bedrock so no worries. I suppose they intend to repair after rainy season?

#10 Chris

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Posted 10 February 2017 - 10:51 AM

Can anyone explain what the "Emergency spillway" there is exactly? All the diagrams I have seen just show a red squiggly line to the left of the spillway that goes down the hillside and through trees. There appears to be no structure for the water to flow. And how do they open this? Is there another gate that feeds this? It doesn't appear so. 

 

And if they open this emergency spillway tons of hillside and trees will be swept away and flushed into the rivers. 

 

What a mess. These DWR guys on tv all look confused, like this is the first time they've had to deal with a real emergency. And all of their hard hats and reflective vests look like it's the first time they have been used!

Yep, it's to the left, as you look down on the spillway, or to the North on a map, a long cement berm built slightly lower than the top of the earthen dam.  The kiss of death to an earthen dam is to be over topped, over-topping means failure, period.   That's why they did all that work on Mormon Island dam and put in the new spillway, the Mormon Island dam was the weakest link in the Folsom Lake reservoir.


1A - 2A = -1A


#11 Chris

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Posted 10 February 2017 - 10:56 AM

I heard releasing wAs of utmost importance right now. They said that beneath the spillway it is solid bedrock so no worries. I suppose they intend to repair after rainy season?

Trails, that's a multi year repair for sure.  Look at the Folsom Dam spillway, that's been like ten years in contruction....?   Hey, you guys want to go in on a cement and re-bar supply company somewhere near Oroville....?   Maybe buy a fleet of 50 cement trucks....?    I think we could make a lot of money in the next 5 years....?   Chris


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#12 2 Aces

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Posted 10 February 2017 - 11:01 AM

I found this comment to be a little ominous: 

 

"Neither option is good. More damage to the spillway will mean very expensive and time consuming repairs, but using the emergency spillway will be uncontrolled, with the possibility of levees being breached downstream. There will also be very significant local erosion, with the greatest risk being that this leads to the failure of the emergency spillway itself."



#13 caligirlz

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Posted 11 February 2017 - 06:05 PM

this article has a good picture of the alternative spillways. I was just wondering what communities are in danger if they cant control the release of the water.

 

http://www.latimes.c...0210-story.html



#14 4thgenFolsomite

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Posted 12 February 2017 - 05:05 AM

The only danger would be if levees are breached. Zero for us to worry about.
Knowing the past helps deciphering the future.

#15 2 Aces

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Posted 12 February 2017 - 08:52 AM

Pretty good video here:

 

http://www.sacbee.co...e132154774.html






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