Whaley Bridge Evacuated

[Ratman]

That's about the size of it, the reservoir was built when the canal was like the M25, boats all over the place day and night, the water stored was needed. The difference is the cut was vital to business so it was maintained to a high standard. It's now mostly used by pleasure boaters/live aborads so no such maintenance takes place until something like Whaley Bridge happens. I see CaRT are now going to rebuild the whole reservoir not just the slipway. I wonder how they are going to keep the cut open while they do that.

Sounds drastic Yolky, whats prompted them to suggest a full rebuild is needed??

[eggsarascal]

2 hours ago, Ratman said:

Sounds drastic Yolky, whats prompted them to suggest a full rebuild is needed??

Maybe because it isn't fit for purpose, CaRT have said it could be a three year job. I still don't get why they had to let the slipway fail, they've now blocked the inlet, where is all the predicted rainfall going to go now, to the cut/Goyt?

[Ratman]

Will they not just control it from now using man power and pumps like they already are doing because its at a lower level???

[eggsarascal]

2 minutes ago, Ratman said:

Will they not just control it from now using man power and pumps like they already are doing because its at a lower level???

After the event, let it fail and sort it later. It wasn't my or your place threatened with being washed away, that's ok then...

 

Being serious, there is still going to be rainfall that needs diverting to the cut, CaRT didn't act quick enough and haven't maintained the asset they have been trusted with.

[Chalgravesteve]

15 hours ago, eggsarascal said:

Maybe because it isn't fit for purpose, CaRT have said it could be a three year job. I still don't get why they had to let the slipway fail, they've now blocked the inlet, where is all the predicted rainfall going to go now, to the cut/Goyt?

I don't see how they have "let the slipway fail"? I would struggle to believe that the slipway was originally constructed with a void underneath it, if there was a void there all the time, then surely there would be a means of access to that void to ensure that nothing was happening in the void out of sight? So, logically, there shouldn't be a void and the concrete slabs and edges are a reinforced area, on top of the reservoir banking, designed to handle the water from the emergency situation where the reservoir overfills and overtops, so that catastrophic erosion and collapse doesn't occur.

 

I think that with the events of the past few weeks, there is every chance that the reservoir bank itself, made from soft soils and loose aggregate, under the slipway has become damaged through erosion. Clearly they cannot take the risk that a repair to something that has clearly failed once, and a repair onto something that might be unstable as well, so they need to do a rebuild job. If I was them, I would be removing a section of that banking and rebuilding the whole thing in concrete where the new water spillway will go. I would be putting hydraulic sluice gates into it at the same time, so that if you ever had to reduce the water level again, quickly in an emergency, you can do so by opening the gates and controlling the outflow through and an area that is designed to withstand the forces involved, instead of having to lay countless pipes around and over the edge and pumping it out. Open the gates and let gravity do the work for you. I would be putting a double gate on all sluices, and not relying on one gate. 

 

In the meantime, the inflow is blocked and what would be entering the reservoir is directly flowing into the river/canal system? As we move into the winter/high rainfall periods, this might put low lying areas close to those water courses more at risk than they were previously, because the reservoir is not there to absorb short term high volumes of rainfall as it has done for the past 180 years, until they have rebuilt the overflow spillway.

[kinderscout]

The void behind the concrete is created by the flow of water over the overflow due to plants growing between the concrete panel's .

[difflock]

It could be the retrofit "protective" concrete overspill apron was the problem, since it hid what was happening beneath it.

How did the Engineer(s) who designed and constructed the dam make provision for the overspill?

And the surely they must have made provision for safe overspill.

The cheap and cheerful concrete add-on was possibly an ill considered solution, especially if the future stability of the earth bank below was not investigated prior to the decision to concrete over it.

 

[eggsarascal]

1 hour ago, Chalgravesteve said:

I don't see how they have "let the slipway fail"? I would struggle to believe that the slipway was originally constructed with a void underneath it, if there was a void there all the time, then surely there would be a means of access to that void to ensure that nothing was happening in the void out of sight? So, logically, there shouldn't be a void and the concrete slabs and edges are a reinforced area, on top of the reservoir banking, designed to handle the water from the emergency situation where the reservoir overfills and overtops, so that catastrophic erosion and collapse doesn't occur.

 

I think that with the events of the past few weeks, there is every chance that the reservoir bank itself, made from soft soils and loose aggregate, under the slipway has become damaged through erosion. Clearly they cannot take the risk that a repair to something that has clearly failed once, and a repair onto something that might be unstable as well, so they need to do a rebuild job. If I was them, I would be removing a section of that banking and rebuilding the whole thing in concrete where the new water spillway will go. I would be putting hydraulic sluice gates into it at the same time, so that if you ever had to reduce the water level again, quickly in an emergency, you can do so by opening the gates and controlling the outflow through and an area that is designed to withstand the forces involved, instead of having to lay countless pipes around and over the edge and pumping it out. Open the gates and let gravity do the work for you. I would be putting a double gate on all sluices, and not relying on one gate. 

 

In the meantime, the inflow is blocked and what would be entering the reservoir is directly flowing into the river/canal system? As we move into the winter/high rainfall periods, this might put low lying areas close to those water courses more at risk than they were previously, because the reservoir is not there to absorb short term high volumes of rainfall as it has done for the past 180 years, until they have rebuilt the overflow spillway.

This doesn't happen very often, I'm lost for words.

[Stere]

What inceased maintenace could have prevented the slipway failure?

 

 

 

 

[eggsarascal]

39 minutes ago, Stere said:

What inceased maintenace could have prevented the slipway failure?

 

 

 

 

Possibly making sure shrubs/trees don't grow between the concrete slabs allowing water to wash away the earth below?