Whaley Bridge Evacuated

[andy3196]

Somebody was asking if there were any pre CRT photos of the spillway.

 

So far I have only been able to find one, from 2005 at https://www.geograph.org.uk/photo/77850 .

There is also a few seconds of video at https://www.youtube.com/watch?v=wXLVRGxsWgc&feature=youtu.be at 55 seconds in, from June 2012.

 

There are also a few recent, April 2019, photos of the spillway HERE .

Edited August 7, 2019 by andy3196
To turn links into links

[LancaCanal]

29 minutes ago, Mike Todd said:

I seriously doubt that an on-site reservoir keeper would be allowed to clear such vegetation - needs a properly equipped team with safety harnesses etc.

 

Further, it is unlikely today that a resident reservoir keeper would be on duty 24/7/365 and my understanding is that matters came to a head rather quickly - no use having a resident if they are not there. Such cover requires at least a team of four, all fully trained and equipped. In today's context I would much rather go with having go remote monitoring and a very responsive command centre. Also, having a good water management model and system - again my guess, but I suspect that it will being having a significant update to the data at least for Toddbrook, if not for all CaRT reservoirs to give greater headroom without loss of service (more headroom means less capacity)

The previous on-site reservoir keeper had no need to deal with that type of vegetation, as it was dealt with before it got to that stage - safely and easily. Furthermore, long-term residents of WB  have been clear that seeing overtopping and use of the spillway was 'very rare' prior to 2012. Before forecast periods of heavy rain, the keeper  would use the sluices to divert the Todd Brook and other inflow, and lower the water level by use of what one person described as 'the gates at the bottom.'  Thus sufficient headroom was maintained -  enough, when necessary,  to cover for periods of heavy rain during the keepers absence and days off.

 

Since 2012,  several WB residents have contacted the CRT wrt their concerns about the changes they have observed on and around the dam. Their concerns have been dismissed and they have been told they were 'wrong'. 

 

Maybe they were, indeed, wrong, Maybe the breach would have happened even sooner, and more catastrophically, if the keeper had continued diligently keeping the spillway clear of weeds, maintaining appropriate  'headroom' below the spillway, and diverting the inflow according to water levels, expected demand and the weather forecast. Maybe not.

 

I don't know, do you? 

 

 

[Richard10002]

40 minutes ago, andy3196 said:

So far I have only been able to find one, from 2005 at https://www.geograph.org.uk/photo/77850 .

 

There is also a few seconds of video at https://www.youtube.com/watch?v=wXLVRGxsWgc&feature=youtu.be at 55 seconds in, from June 2012.

Fairly clear that there was no shortage of growth in 2005, so the reservoir keeper clearly had little to do with the weeding or organising of it, (in 2005).

 

In the second, in 2012, where the overtopping can be seen, the angle of sidewall seems to guarantee a point of pressure where the water running straight down the slope, hits the wall. I wonder if this point coincides with the bottom of the area where the concrete has lifted.

 

 

[ditchcrawler]

10 hours ago, frangar said:

Why not have someone on site...like thames lockies & canal lengthsmen. Their salary would be cheaper than what’s just happened. Sadly the bigger picture is never looked at until it’s too late. 

What would he do, blow a hooter if it was going to fail

[frangar]

1 minute ago, ditchcrawler said:

What would he do, blow a hooter if it was going to fail

Make sure it didn’t fail?? Seemed to have worked well over the years. 

[Wanderer Vagabond]

1 minute ago, frangar said:

Make sure it didn’t fail?? Seemed to have worked well over the years. 

You might have missed the noticeable change in the weather over recent years, I can still remember the  days when it used to just rain, not come down in increasingly regular monsoon downpours. I suspect a lot of water control methods are going to need looking at.

[frangar]

2 minutes ago, Wanderer Vagabond said:

You might have missed the noticeable change in the weather over recent years, I can still remember the  days when it used to just rain, not come down in increasingly regular monsoon downpours. I suspect a lot of water control methods are going to need looking at.

I still think someone on site would be better than any remote monitoring...not just for dams but for all major infrastructure...a sensor doesn’t always save cash in the long run 

[Richard10002]

44 minutes ago, frangar said:

I still think someone on site would be better than any remote monitoring...not just for dams but for all major infrastructure...a sensor doesn’t always save cash in the long run 

Despite my comment on the 2005 pic above, I agree.

 

I used to work on ocean going ships where, during my time, the engine rooms became more and more automated. The engineers would all go to bed, one would be the duty engineer and, if an alarm went off, they were into the control room from being fast asleep pretty sharpish. If the issue was beyond them, they would call someone with more experience.... 2nd engineer, or Chief.

 

It shouldn't be too difficult to have an alarm system which monitors both the depth and the rate of increase in depth and, if either, or both, exceed the limit, an alarm goes of, and the keeper takes a look and does what is necessary. In most cases i can imagine that the solution to avoid overtopping, (or whatever the issue was), would be to open some valves and maybe make some calls down the line. In the extreme, it might be to evacuate the town. The latter is less likely/unlikely if someone is on site.

 

I wonder how long before the overtopping started was somebody on site opening valves. Or did things only begin after the overtopping started, or even after the damage was noticed. 

[andy3196]

https://www.sciencemediacentre.org/expert-reaction-to-news-that-the-whaley-bridge-dam-has-been-damaged/  may be of interest.

[ditchcrawler]

1 hour ago, frangar said:

Make sure it didn’t fail?? Seemed to have worked well over the years. 

But how would he do that,

[Richard10002]

3 minutes ago, ditchcrawler said:

But how would he do that,

Spot the water rising fast, and do something that keeps the level below the spillway?

[Murflynn]

9 hours ago, andy3196 said:

https://www.sciencemediacentre.org/expert-reaction-to-news-that-the-whaley-bridge-dam-has-been-damaged/  may be of interest.

very much so.  thanks for the link.  

[Mike Todd]

11 hours ago, ditchcrawler said:

What would he do, blow a hooter if it was going to fail

We clearly have no idea whether an on site reservoir keeper would have made any difference until we know the actual failure mode, which at this time has not been spoken about by CaRT's engineers. All we know is the result which is not helpful in planning future action.

[Mike Todd]

11 hours ago, frangar said:

I still think someone on site would be better than any remote monitoring...not just for dams but for all major infrastructure...a sensor doesn’t always save cash in the long run 

On another thread there have been comments about how alert bridge watch keepers are on the G&S. Clearly in any role that is mainly about sitting and waiting for a rare event then there are dangers that, just at the moment of need, the person is somewhere else, literally or otherwise. 

 

In any case, we have to factor in a cost issue. CaRT, like any engineering organisation, has a limited budget, even if it is said that reservoir safety is a priority item. For any given risk level, there will be alternative approaches and it is essential that in an on-going way, efforts are made to adopt the most cost effective one. Of course, there are capital as well as revenue aspects to the consideration.

 

The principal advantage of a human on the ground is if they have the ability to think through the unexpected. Remote sensors are probably, at present, the most cost effective way of monitoring for a 'rare' event but all that does depend on making the right assumptions about the possible failure modes. Sensors will not look for things that the designer does not specify! Equally, there are plenty of engineering cases of humans making a situation worse if they do not fully understand the implications of what they are doing.

 

I'm betting on the investigation (should it be reported publicly) concluding:

 

1. More than one thing 'went wrong' or parameters exceeded known limits

2. The initial actions on site were not sufficient to handle the degree of excess

3. The failure mode was not in the design spec

 

oh, and

 

4. None of the 'it was always better in the past' suggestions of how it could have been avoided actually mattered.

1 hour ago, Murflynn said:

very much so.  thanks for the link.  

Indeed - especially a they generally also suggest a similar failure mode to that which I put forward a few pages back!

[Murflynn]

3 hours ago, Mike Todd said:

 

Indeed - especially a they generally also suggest a similar failure mode to that which I put forward a few pages back!

well done that man   

 

 

......................   or you could go a few pages further back   ...........................  

[BruceinSanity]

7 hours ago, Mike Todd said:

More than one thing 'went wrong' or parameters exceeded known limits

I’ve seen it quoted in a book on the psychology of fatal errors that the typical AAIB report identifies 40 contributing factors to the plane falling out of the sky.

[Murflynn]

whenever I was involved in undertaking accident investigations, in a couple of cases involving multiple fatalities, there was a similar result, however the fundamental root cause boiled down to management failure, which was common to every incident.

[AndrewIC]

21 hours ago, Richard10002 said:

Spot the water rising fast, and do something that keeps the level below the spillway?

If the water comes in much faster than it can get out, as it would when a months rain falls in half a day (or whatever the numbers were, something of that order) with little notice, and the drain valves are relatively small (2 x 15in pipes according to the site about their refurbishment), then there’s probably not a lot you can but watch from a safe distance. The alternative is to keep the reservoir much emptier.

[Murflynn]

21 minutes ago, AndrewIC said:

If the water comes in much faster than it can get out, as it would when a months rain falls in half a day (or whatever the numbers were, something of that order) with little notice, and the drain valves are relatively small (2 x 15in pipes according to the site about their refurbishment), then there’s probably not a lot you can but watch from a safe distance. The alternative is to keep the reservoir much emptier.

no totally 'watertight' (no pun intended) solution can be found unless you define the maximum event you are planning for.............  this is defined statistically as a 10 year, 100 year, or perhaps 1000 year event (i.e. the statistical timespan between a repetition of such an event) .................. trouble is that with climate change all the statistical forecasts are no longer valid.   ........................ Catch 22 applies.

Edited August 8, 2019 by Murflynn

[MtB]

4 hours ago, AndrewIC said:

If the water comes in much faster than it can get out, as it would when a months rain falls in half a day (or whatever the numbers were, something of that order)

 

I don't buy this recent fashion for defining daily rainfall in 'months'-worth'.

 

Plenty of months pass with no rainfall at all so a month's rain in half a day can still be no rain whatsoever.

 

 

[Murflynn]

6 hours ago, Mike the Boilerman said:

 

I don't buy this recent fashion for defining daily rainfall in 'months'-worth'.

 

Plenty of months pass with no rainfall at all so a month's rain in half a day can still be no rain whatsoever.

 

 

exactly - but it keeps the meedya in bizness, innit?

 

perhaps the meedya would find more fertile ground in the Gulf countries, where typically it might drizzle for an hour or so 2 days a year and then the next year the roads in a major city like Abu Dhabi are a foot deep in water from a local storm.  They could say '5 years' rain in an hour'.

[cuthound]

11 hours ago, Murflynn said:

no totally 'watertight' (no pun intended) solution can be found unless you define the maximum event you are planning for.............  this is defined statistically as a 10 year, 100 year, or perhaps 1000 year event (i.e. the statistical timespan between a repetition of such an event) .................. trouble is that with climate change all the statistical forecasts are no longer valid.   ........................ Catch 22 applies.

 

Indeed. In the mid 70's BT designed their cooling units to keep the proposed digital telephone exchanges at 45°C with an outside temperature of 35°C, then statistically a once in a 100 year event.

 

By the 90's they were having to provide occasional additional cooling as the 35°C summer day had become a once in 10 year event.

 

Today almost every summer has a day that reaches 35°C.

[Machpoint005]

On 07/08/2019 at 22:48, andy3196 said:

https://www.sciencemediacentre.org/expert-reaction-to-news-that-the-whaley-bridge-dam-has-been-damaged/  may be of interest.

Excellent post and reference, thank you.

Many on here will still find it more fun to speculate from a zero knowledge base, though.

[Murflynn]

2 minutes ago, Machpoint005 said:

Excellent post and reference, thank you.

Many on here will still find it more fun to speculate from a zero knowledge base, though.

          

[Nightwatch]

I have written to BW and latterly CRT asking if their contractor is responsible for cutting to the edge of the bank. There's evidence of this not happening and weeds and other stuff that I don't know the titles of, grow into, eventually, small bushes and small trees the the contractor is certainly not responsible to cut and clear, even though if they had done their job to the specification in the first instance there wouldn't be small bushes and small trees to remove. These bushes and trees damage the bank and associated fittings.

Edited August 9, 2019 by Nightwatch