Toddbrook Dam Collapse, Whaley Bridge, UK

[Mick West]

https://www.facebook.com/BBCNW/photos/a.124055177625553/2582326188465094/?type=3&theater

https://www.facebook.com/BBCNW/videos/2138513586446717/


Source: https://twitter.com/DanBond0/status/1156927854019563522


Reminiscent of the Orville spillway, but this time the spillway is on the face of the (much smaller) dam, so continued erosion could lead to a total collapse.

This is in the North of England, where I'm from, small towns and villages in narrow valleys. The town of Whaley Bridge, directly under the reservoir, is currently being evacuated.

 

[Mick West]

Here's the evacuation area, about 6,000 people.

 

[Mick West]

Weather not cooperating

 

[Mick West]

Source: https://twitter.com/DerPolDroneUnit/status/1156930879144509441

Source: https://twitter.com/BBCDerby/status/1156935775281451010



There's very little flow right now, but with a week of rain ahead another overtopping is possible.

 

[Rory]

Weather not cooperating
View attachment 37881

That looks bad. But if it included the amount of rain that is predicted to fall, it would show how bad.

Here's one that does that:

https://www.yr.no/place/United_Kingdom/England/Whaley_Bridge/long.html

4mm tomorrow, 1.6mm on Sunday, 16.5mm on Tuesday (0.6 inches), and the other days around 5mm (0.2") per day.

 

[deirdre]

cant they just throw some sandbags over the bad area to divert the water to the ok side?

edit add... I see, it isn't the spillway hole that's the problem so much, its the river set up down stream is breaking apart. (not seen in this photo, just included to give perspective)

add2

 

[jonnyH]

cant they just throw some sandbags over the bad area to divert the water to the ok side?

Source: https://twitter.com/RobSharp170/status/1157030454245171206?s=09

 

[Mick West]

They are filling the hole with bags of aggregate (sand and gravel)

Source: https://twitter.com/ODN/status/1157297182929821697


They are also draining and pumping out as much as they can, as well as blocking the inlets to the reservoir - which I presume can only be a temporary measure to slow the inflow while they shore it up, as there does not seem to be a way of diverting the water around the dam.

Nice weather though!

 

[deirdre]

I meant like this guy is doing.. (but once I saw how fast the water sometimes comes down I thought I was being silly, guess not. hope it all works!)

 

[deirdre]

a nice pic (ie. easier perspective) of what's 'downstream' if the dam wall/berm blows

 

[Mick West]

2016 Footage of the auxillary spillway shows it was poorly maintained:

Source: https://www.youtube.com/watch?v=_pOu5AHJ1U8


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This panel in particular looks like it's sunk in:

 

[deirdre]

2016 Footage of the auxillary spillway shows it was poorly maintained:

Wow! that's pretty bad. I didn't even realize originally how 'thin' the berm was at the top, used to looking at Orville I guess.

Read this morning, they have 35% of the water out of the reservoir and are going to do a total rebuild.

 

[cloudspotter]

2016 Footage of the auxillary spillway shows it was poorly maintained:

And it is only 50 years old. Added to the dam in 1969 when the existing spillway capacity was deemed inadequate

https://books.google.co.uk/books?id=hgwkDwAAQBAJ&pg=PT227&lpg=PT227#v=onepage&q&f=false

Reading through Toddbrook's Wiki page it seems that it has always had problems and may not even have been built to the original specifications

https://en.wikipedia.org/wiki/Toddbrook_Reservoir

 

[Mick West]

A better scan of the above link:
Binnie, G. (1974). The Evolution of British Dams. Transactions of the Newcomen Society, 47(1), 207–224. doi:10.1179/tns.1974.015
https://www.tandfonline.com/doi/abs/10.1179/tns.1974.015?journalCode=yhet19

Fig. 13. Todd Brook Dam 1968. Photo by courtesy of the North West Water Authority

Fig. 14. Todd Brook Dam Main Spillway.

Fig. 15. Todd Brook Dam 1978, with auxiliary Spillway.

Plants were growing out of it in 1976! Still, if it was not there, the dam probably would have failed.

 

[Gary McH-P]

Badly maintained!! A small tree growing and plant-shrub roots are not exactly helpful in the gaps between the concrete sections. Over time they will crack and break up the sections, severely weakening it. Which is what has happened to that section that has been undermined, collapsed and washed away. Amazingly it passed its last inspection! .https://www.bbc.co.uk/news/uk-england-derbyshire-49220650

The Canal and River Trust (CRT), which owns the dam, said it adhered to regulations requiring reservoirs to be supervised, inspected and maintained by certified reservoir engineers.

"This includes regular, detailed 10-yearly inspections carried out by an independent Panel Engineer and CRT Supervising Engineer," it said in a statement.

"The last one was undertaken in November 2018 and signed off by the independent Panel Engineer and CRT Supervising Engineer in April 2019.