Whaley Bridge dam collapse

So long as they get it sorted so I can get to my isolation area for when the snow comes :)
 
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The problem is that our dams here in the Peak District ( and I suppose most others) were built by the Victorians nearly 200 years ago and are mainly composed of earth and stones and clad with pretty looking pieces of masonry. They start off many metres thick and taper until they just a couple at the top. very little investment has been made other than plugging the odd leak, so this was bound to happen, and as long as we keep building on flood plains it is going to get worse. Our town, amongst other, was badly flooded a few years ago, so they improved our flood defences. How? By scraping out the river and brook and lining then with stone setts, so now the water flows rapidly straight through and on to the next poor souls down stream. I agree that things have in recent years got more difficult, but in many cases we are the creators of our misfortune as far as the flooding goes
There is very tight legislation and registration about dams above quite a small storage capacity which becomes even more stringent if failure would present a significant loss of life as in this case.
Therefore to suggest a lack of maintenance without evidence is unfair.
There will have been regular inspections and recertification by a specialist engineer.
However an earth same is only as good as the 'skins' front and back that serve to protect the main body and its central waterpoof core so when an extraordinary overflow manages to disturb the spillway and get underneath it the danger of further erosion and collapse is very significant.
It will be interesting to hear in due course whether the seal between the slabs in the spillway were inspected and maintained.
 
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There is very tight legislation and registration about dams above quite a small storage capacity which becomes even more stringent if failure would present a significant loss of life as in this case.
Therefore to suggest a lack of maintenance without evidence is unfair.
There will have been regular inspections and recertification by a specialist engineer.
However an earth same is only as good as the waterproofing skins front and back so when an extraordinary overflow manages to disturb the spillway and get underneath it the danger of further erosion and collapse is very significant.
It will be interesting to hear in due course whether the seal between the slabs in the spillway were inspected and maintained.
And remember that this a canal reservoir at the start of the Peak canal
 
Yes a surge along the canal would seem inevitable, and since it is a contour canal it grows ever higher along the valley side and in overflowing would threaten a lot more properties than only those in the valley bottom. Rather alarming also for those with narrowboats who presumably have been evacuated without any chance to (invariably slowly) move them out of harms way.
Since we live below Ladybower and the Derwent and Howden dams I have to say I’m rather glad to say 20th C dam engineering seems to have been rather more robustly engineered than 18th C....er I hope!
 
The soil reverse of the dam with concrete slabs on top is only in danger of collapse if the spill water comes over the top taking the earth bank away and thus weakening the actual dam wall, however they have managed to lower the level so that should not happen, poor maintenance allowed water through the spill plates effectively floating them off. Bad design that needs to be rectified.
 
Segmented slab spillway are very common on this sort of dam.
From what I read the spillway was widened in the 60s.
The design is not in itself bad but if the joints are not effectively sealed and dowelled together it is susceptible to damage by extraordinary flows such as happened last week.
Once the slabs become disturbed or water gets underneath the spillway can fail very quickly.
Maintenance may yet prove to be a significant factor - there will no doubt be a report in due course.
I think you are right in thinking that this sort of spillway will come under close scrutiny and I wouldn't be at at all surprised if they are replaced on higher risk dams with something more robust.
 
Mastic and gaffer tape should hold.
Gorilla Glue seems to be the "go To" stuff these days.
Seriously though, if that dam had failed during the heaviest rain every house in the waters path would have been flattened and the bricks washed down the valley. Look what happened to dry stone walls in the Yorkshire Dales with only run off water from the hills.
 
I read that they've identified another 50 or so similar dams 13 of which are in the highest risk category.
Environment Agency are chasing owners to ensure any outstanding remedials are completed ASAP.
 
We have 7 in our area
 

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