Toddbrook Reservoir

[JohnfromUK]

I read a post elsewhere that suggests that part of the problem that has lead to this (potential major) disaster is due to the actions of Natural England.  

The post says that much of the water that feeds Toddbrook comes from the Goyt moors – Cat and Fiddle area.  Now it seems that this was a managed drained moor, but Natural England have been busying themselves blocking up all of the drainage channels and trying to make the moor a saturated bog to grow sphagnum (which takes decades to grow and integrate).  The outcome is that instead of behaving like a sponge and soaking up heavy rainfall and releasing it over a long period, the ground is now always partly saturated and heavy rain runs off much faster.  In addition much smaller wildlife like voles have been flooded out.

The post goes on to suggest "With such extreme weather patterns appearing its time Natural England reversed their damaging moorland management and open up the drains to dry up the moors and restore controlled heather burning creating heather/herbs mosaics and restore the lost water vole habitats.".

I don't personally know the area, but does anyone here have any local knowledge or light to shed on this topic?

[Rewulf]

3 minutes ago, JohnfromUK said:

I read a post elsewhere that suggests that part of the problem that has lead to this (potential major) disaster is due to the actions of Natural England.

Thats strange , I was assuming it was down to Brexit, or 'Damned tory austerity' 🙄

Seriously though, the rain lately has been biblical.

[Scully]

I can’t comment on the validity of the claims, but thought it weird that given ‘it could go at any time’, there were men on the news last night ( engineers I’m assuming ) walking along the top of it to view the erosion. 🤔

[JohnfromUK]

My guess (and it is mainly that) is that being an apparent pudded clay cored dam, held in place and protected by external cladding/cover, it 'goes' when the clay core is displaced (by the weight of water - or by being washed away).  I assume that is a process of many minutes at least - if not an hour or two?  Not enough to evacuate a town, but enough to scamper to one side of a steel walkway.

I assume the engineers know what they are taking in the way of risks.

[islandgun]

27 minutes ago, JohnfromUK said:

I read a post elsewhere that suggests that part of the problem that has lead to this (potential major) disaster is due to the actions of Natural England.  

The post says that much of the water that feeds Toddbrook comes from the Goyt moors – Cat and Fiddle area.  Now it seems that this was a managed drained moor, but Natural England have been busying themselves blocking up all of the drainage channels and trying to make the moor a saturated bog to grow sphagnum (which takes decades to grow and integrate).  The outcome is that instead of behaving like a sponge and soaking up heavy rainfall and releasing it over a long period, the ground is now always partly saturated and heavy rain runs off much faster.  In addition much smaller wildlife like voles have been flooded out.

The post goes on to suggest "With such extreme weather patterns appearing its time Natural England reversed their damaging moorland management and open up the drains to dry up the moors and restore controlled heather burning creating heather/herbs mosaics and restore the lost water vole habitats.".

I don't personally know the area, but does anyone here have any local knowledge or light to shed on this topic?

good points, and they should certainly be taken seriously.. nothing would surprise me from those who would save the world but cant be bothered or are unable to think it through first.

[Westley]

THEY were probably all the apprentice engineers and as such were expendable  !    🤔

[Mice!]

3 hours ago, JohnfromUK said:

My guess (and it is mainly that) is that being an apparent pudded clay cored dam, held in place and protected by external cladding/cover, it 'goes' when the clay core is displaced (by the weight of water - or by being washed away).  I assume that is a process of many minutes at least - if not an hour or two?  Not enough to evacuate a town, but enough to scamper to one side of a steel walkway.

I assume the engineers know what they are taking in the way of risks.

The problem was caused by the water coming over the top of the damn, probably washing away some of the cladding, apparently it's never happened before, so if NE are involved it will be interesting.

I saw all the folk on the news looking down and didn't think it looked like a good place to be, pretty sure if all that water does come out those house are going to be in serious trouble.

1 hour ago, Westley said:

THEY were probably all the apprentice engineers and as such were expendable  !    🤔

😂😂😂  always more available 

[mossy835]

so it could be that NE cocked up again.

[figgy]

It's all ok now Boris flew in and sorted it. 

[oldypigeonpopper]

hello, i just heard the Dam is owned by a charity and not had much repairs unlike those owned by water companies

[figgy]

If that's true it may be landed with a huge bill. Them Chinooks are not cheap to fly.

[wascal]

3 minutes ago, figgy said:

If that's true it may be landed with a huge bill. Them Chinooks are not cheap to fly.

£3500 per hr

[Saltings]

7 hours ago, JohnfromUK said:

I read a post elsewhere that suggests that part of the problem that has lead to this (potential major) disaster is due to the actions of Natural England.  

The post says that much of the water that feeds Toddbrook comes from the Goyt moors – Cat and Fiddle area.  Now it seems that this was a managed drained moor, but Natural England have been busying themselves blocking up all of the drainage channels and trying to make the moor a saturated bog to grow sphagnum (which takes decades to grow and integrate).  The outcome is that instead of behaving like a sponge and soaking up heavy rainfall and releasing it over a long period, the ground is now always partly saturated and heavy rain runs off much faster.  In addition much smaller wildlife like voles have been flooded out.

The post goes on to suggest "With such extreme weather patterns appearing its time Natural England reversed their damaging moorland management and open up the drains to dry up the moors and restore controlled heather burning creating heather/herbs mosaics and restore the lost water vole habitats.".

I don't personally know the area, but does anyone here have any local knowledge or light to shed on this topic?

makes sense been there for many years with no major issues ,  not that many years ago we had more extreme rainfall and flash folding all over the county bridges out property damage , human intervention ,  with no knowledge of the local environment but an expert who read in a book   (changing something that has worked for hundreds of years , if its not broke don't fix it ) 

[mick miller]

Mate is down there with mountain rescue at the moment.

[Jaymo]

I like how it was described as being made of “mud and clay” ! Think the Concrete outer capping is purely decorative and to lull those living nearby that it’s structurally sound solid piece of engineering- not something made by Tarka the otter.

This is near us and we have visited many times- the size of some of the washed down concrete blocks are the size of houses ( useless piece of trivia, if your ever watched the series “The returned” - parts of it were filmed there)

https://en.m.wikipedia.org/wiki/Malpasset_Dam

Edited August 3, 2019 by Jaymo

[Mice!]

It's just said on BBC News that there is a big storm forecast for tomorrow!! Make or break.

[old man]

Just an engineered structure of the age?

Looks to my amateur eye that the problem is that water has been allowed to undercut the concrete skirt of the spillway causing the collapse?

Lack of regular inspections?

[oldypigeonpopper]

9 hours ago, oldypigeonpopper said:

hello, i just heard the Dam is owned by a charity and not had much repairs unlike those owned by water companies

hello,  the canal and river trust,   

Edited August 3, 2019 by oldypigeonpopper

[figgy]

Looks much like that dam that let go in America where it was undercut and too layer of concrete was washed away.

Puddling clay is only a thin waterproof skin, any breech and water will start to get through and leach its way out taking soil with it.

Victorians used puddling clay for ponds lakes everything for water retaining on a large scale.

Probably quite hard to inspect below the concrete skin, first you know is when it goes.

Edited August 3, 2019 by figgy

[old man]

The one I had a bit to do with was much smaller but it had stainless rods installed vertically at intervals on the bank top, these were regularly checked for position to detect slippage.

[JohnfromUK]

From what I read, when this dam gets full, excess water runs out of an overflow spillway made in concrete round one side. 

Under severe conditions when this is not adequate, water is allowed to 'overtflow' and run down the reserve slipway on the main (dry side) face of the dam.  This is also concrete - which prevents the water scouring away the earth construction of the main dam wall.

The main dam wall consists of a relatively thin clay (waterproof) layer banked up by soil/earth both sides.  The weight and bulk of this earth holds the clay core in place.

What has gone wrong is that the concrete of the reserve slipway has failed and broken up in one region (right hand side viewed from downstream).  This has meant that the overflowing water has scoured away some of the earth from the 'dry side', thus reducing the weight/bulk holding the waterproof clay core in place.

If the clay core is allowed to bulge/crack and water begins to leak through, it will rapidly scour away clay and earth and total failure is likely to follow quickly.

What they are trying to do is twofold;

1. Reduce water in the dam to reduce pressure, reduce risk of overspill, minimise contents should the worst happen
2. Add weight/bulk where this has been lost to support the clay core and prevent it bulging/cracking

Possibly the concrete slipway has slowly been undermined by years of leakage under the slabs seems a major possible cause.

[oldypigeonpopper]

On 02/08/2019 at 16:39, Scully said:

I can’t comment on the validity of the claims, but thought it weird that given ‘it could go at any time’, there were men on the news last night ( engineers I’m assuming ) walking along the top of it to view the erosion. 🤔

hello, your right Scully sky news has just remarked on why are the some many men in orange jackets ambling back and forth along the walk way and who are they, structural engineers, Dam experts, jobs worth council workers, i would have thought they would have roped off the walk way, or say let on 2 at a time with safety ropes, looks like the firemen and maybe ladies are doing a great job with the pumps, seems very little work has been done on the Dam wall for years and looked after by the canal and river trust, from johns description above built in 1831 opened in 1838, i am sure its time for a complete up grade as Boris mentioned, we seem to be having more of these flash flooding weather patterns and previous years other parts of the UK have had  rivers burst with catastrophic results, lets hope Toddbrook will not be another one, 

[bluesj]

I don't think it any difference who owns the dam they are all subject to the same inspections and maintained to the same regulations by law. 

[Yellow Bear]

4 hours ago, JohnfromUK said:

Possibly the concrete slipway has slowly been undermined by years of leakage under the slabs seems a major possible cause.

This is probably the case, however the "reserve spillway" did not get a lot of use over the years and the problem may have been greatly exacerbated by NE "playing god as you alluded to earlier.

[oldypigeonpopper]

15 minutes ago, bluesj said:

I don't think it any difference who owns the dam they are all subject to the same inspections and maintained to the same regulations by law. 

hello, your right last inspection November 2018, but it does work on a shoe string budget and volunteers