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RhynoCZ |
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RhynoCZ Super Spammer
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doggone |
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doggone World Chat Champion
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Freddyfruitba... |
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Freddyfruitba... World Chat Champion
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Riejufixing |
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Riejufixing World Chat Champion
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Posted: 13:55 - 10 Aug 2019 Post subject: |
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Freddyfruitbat wrote: | In the absence of an actual hurricane, I don't really understand what the bad weather has to do with it. I mean - a dam is just a big wall which holds back a load of water to form a reservoir. If it rains, the reservoir fills up, after which it will just overflow down the spillway. It's not like a sea wall defence, which is subject to stormy seas smashing repeatedly against it, is it? |
No, it isn't, but there are a number of possible problems. Negative pressure along the spillway crest can give rise to lifting forces. Cavitation can erode the concrete face of the spillway. Both are possible in this case (to say nothing of possible alignment issues due to ground conditions). Once there's any penetration of the spillway face (or the bulk of the shell from any source), things can go bad quite quickly, as seen in various footage where discoloration of the water due to entrained material from the shell of the dam (underneath the spillway) is quite plain.
This shows some interesting video of the general conditions, and at 5:04 the crest of the spillway which perhaps may at some time be called a design issue (in view of increasing flows):
https://www.youtube.com/watch?v=xzXJpK_QcFo
This picture shows the damage quite well:
https://i2-prod.manchestereveningnews.co.uk/incoming/article16685331.ece/ALTERNATES/s1200b/0_JS189186259.jpg
The bad weather increased the flow over the crest of the dam to unforseen levels, which seems to have been the issue. |
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MCN |
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doggone |
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doggone World Chat Champion
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Posted: 15:13 - 10 Aug 2019 Post subject: |
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When he looks down from the walkway you can clearly see a large willow or birch flailing in the water at the damaged area. Further across an ash sapling looks to be 4 or 5 years old.
All the disturbances in the flow are caused by excessive vegetation at the joints.
It's a poor design how it funnels the flow on one side with risk of erosion where it overtops the channel at the bottom, however the failed area seems to be higher up where that effect was less. |
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Riejufixing |
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Riejufixing World Chat Champion
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MCN |
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MCN |
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MCN Super Spammer
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Posted: 21:22 - 10 Aug 2019 Post subject: |
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https://youtu.be/k53Q147Y3x0
Dam dams. ____________________ Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN. |
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Old Thread Alert!
The last post was made 4 years, 260 days ago. Instead of replying here, would creating a new thread be more useful? |
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