A83 Rest And Be Thankful blocked again

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Mark Hewitt
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Re: A83 Rest And Be Thankful blocked again

Post by Mark Hewitt » Sat Jan 22, 2022 21:36

swissferry wrote:"Preliminary ground investigations are expected to get underway next month, as part of the design work to identify a preferred route option for the long term solution for the A83 at the rest and Be Thankful."

"In recognition of the urgency to find a solution Transport Scotland is also progressing work to develop a medium term resilient route through Glen Croe while the long term solution is developed. We will bring forward proposals for this by late 2022. This work includes consideration of utilising the existing forestry track."

https://www.transport.gov.scot/news/18- ... tion-work/
Is the forestry track the military road?
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Re: A83 Rest And Be Thankful blocked again

Post by Burns » Sat Jan 22, 2022 21:37

Switzerland would have put a concrete shelter over the A83 decades ago.

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Re: A83 Rest And Be Thankful blocked again

Post by swissferry » Sat Jan 22, 2022 21:56

Mark Hewitt wrote:
Sat Jan 22, 2022 21:36
swissferry wrote:"Preliminary ground investigations are expected to get underway next month, as part of the design work to identify a preferred route option for the long term solution for the A83 at the rest and Be Thankful."

"In recognition of the urgency to find a solution Transport Scotland is also progressing work to develop a medium term resilient route through Glen Croe while the long term solution is developed. We will bring forward proposals for this by late 2022. This work includes consideration of utilising the existing forestry track."

https://www.transport.gov.scot/news/18- ... tion-work/
Is the forestry track the military road?
I'm assuming its referring to the forestry track on the other side of the Croe Water from the Old Military Road, which is why I thought it was interesting.

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Re: A83 Rest And Be Thankful blocked again

Post by Mark Hewitt » Sun Jan 23, 2022 07:26

swissferry wrote:
Sat Jan 22, 2022 21:56
Mark Hewitt wrote:
Sat Jan 22, 2022 21:36
swissferry wrote:"Preliminary ground investigations are expected to get underway next month, as part of the design work to identify a preferred route option for the long term solution for the A83 at the rest and Be Thankful."

"In recognition of the urgency to find a solution Transport Scotland is also progressing work to develop a medium term resilient route through Glen Croe while the long term solution is developed. We will bring forward proposals for this by late 2022. This work includes consideration of utilising the existing forestry track."

https://www.transport.gov.scot/news/18- ... tion-work/
Is the forestry track the military road?
I'm assuming its referring to the forestry track on the other side of the Croe Water from the Old Military Road, which is why I thought it was interesting.
Ah yes I see it on the map. That would he interesting! Bascially abandon the road as it exists now.

I wonder if a full new S2 through forest is going to work out better/cheaper than a rock shelter?
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Re: A83 Rest And Be Thankful blocked again

Post by SteelCamel » Fri Jan 28, 2022 21:45

Mark Hewitt wrote:
Sun Jan 23, 2022 07:26
swissferry wrote:
Sat Jan 22, 2022 21:56
Mark Hewitt wrote:
Sat Jan 22, 2022 21:36

Is the forestry track the military road?
I'm assuming its referring to the forestry track on the other side of the Croe Water from the Old Military Road, which is why I thought it was interesting.
Ah yes I see it on the map. That would he interesting! Bascially abandon the road as it exists now.

I wonder if a full new S2 through forest is going to work out better/cheaper than a rock shelter?
I presume the "short term option" they're looking at is surfacing the track to use as a backup road, in the same way that the old military road is. The landslips can block the old military road too, but the track is on the opposite slope so should avoid this issue - at the very least, it's highly unlikely all three would be blocked at once. I'd guess it would be similar to the old miltary road - an S1 without passing places, used with a convoy system. Though of course if the old military road is available, it opens the possibility of running both backup routes one-way to make a kind of D1, and so avoiding the need to run in convoy.

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Re: A83 Rest And Be Thankful blocked again

Post by Mark Hewitt » Sat Jan 29, 2022 08:36

SteelCamel wrote:
Mark Hewitt wrote:
Sun Jan 23, 2022 07:26
swissferry wrote:
Sat Jan 22, 2022 21:56
I'm assuming its referring to the forestry track on the other side of the Croe Water from the Old Military Road, which is why I thought it was interesting.
Ah yes I see it on the map. That would he interesting! Bascially abandon the road as it exists now.

I wonder if a full new S2 through forest is going to work out better/cheaper than a rock shelter?
I presume the "short term option" they're looking at is surfacing the track to use as a backup road, in the same way that the old military road is. The landslips can block the old military road too, but the track is on the opposite slope so should avoid this issue - at the very least, it's highly unlikely all three would be blocked at once. I'd guess it would be similar to the old miltary road - an S1 without passing places, used with a convoy system. Though of course if the old military road is available, it opens the possibility of running both backup routes one-way to make a kind of D1, and so avoiding the need to run in convoy.
Is the forest road also liable to land slip? As if not it would seem to be that building full S2 through the forest and make that the A83.
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Re: A83 Rest And Be Thankful blocked again

Post by KeithW » Sat Jan 29, 2022 09:38

Mark Hewitt wrote:
Sat Jan 29, 2022 08:36
Is the forest road also liable to land slip? As if not it would seem to be that building full S2 through the forest and make that the A83.
The Forestry Commission may have other ideas, in 2020 they installed gates at each end as unauthorised traffic was causing them problems.
https://lochgoilhead.info/glen-croe-for ... ouncement/

As I recall the Scottish Government had identified a new permanent route last year and the Forest Road was intended as an interim measure while the new road was being built.
https://www.highwaysmagazine.co.uk/Math ... r-A83/8931

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Re: A83 Rest And Be Thankful blocked again

Post by SteelCamel » Sat Jan 29, 2022 18:10

Mark Hewitt wrote:
Sat Jan 29, 2022 08:36
Is the forest road also liable to land slip? As if not it would seem to be that building full S2 through the forest and make that the A83.
Yes, probably. It's on a shallower slope, and has trees, so may have less landslips, but probably still some. As I see it the point of the temporary option is that you're unlikely to have slips on both sides of the glen at the same time.

And as in the link KeithW has posted, re-routing the A83 through the forest is one option under consideration for the permanent route, though not the only one.

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Re: A83 Rest And Be Thankful blocked again

Post by swissferry » Sun Jan 30, 2022 18:57

I've seen the aftermath of numerous landslips around that area, including one above though not reaching the forest tracks on the other side of the Croe Water. While trees reduce the risk of landslips I have been surprised how far into forested areas they do penetrate. I've seen several in Gleann Leaccann Sheileach (5km to the east of the Rest) which have started above the forest and reached beyond the forest track. From what I've seen I reckon the landslips are closer to a fluid than solid so still flow easily through forest with bigger slips taking the trees with them.

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Re: A83 Rest And Be Thankful blocked again

Post by Mark Hewitt » Sun Jan 30, 2022 19:06

swissferry wrote:I've seen the aftermath of numerous landslips around that area, including one above though not reaching the forest tracks on the other side of the Croe Water. While trees reduce the risk of landslips I have been surprised how far into forested areas they do penetrate. I've seen several in Gleann Leaccann Sheileach (5km to the east of the Rest) which have started above the forest and reached beyond the forest track. From what I've seen I reckon the landslips are closer to a fluid than solid so still flow easily through forest with bigger slips taking the trees with them.
Cheers. It seems a rock shelter would be the most effective then or a tunnel.
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Re: A83 Rest And Be Thankful blocked again

Post by Enceladus » Sun Jan 30, 2022 19:57

Would climate change be partially responsible for all these landslips at Rest And Be Thankful?

The A83 is a critical and vital link between Kintyre and its environs to the central belt of Scotland so addressing this persistent problem with a long-term solution is very important.

Would there be the possibility of a completely new route for the A83 well away from this location?
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Re: A83 Rest And Be Thankful blocked again

Post by owen b » Mon Jan 31, 2022 19:07

Enceladus wrote:
Sun Jan 30, 2022 19:57
Would climate change be partially responsible for all these landslips at Rest And Be Thankful?
This article suggests it is : https://blogs.agu.org/landslideblog/202 ... -thankful/
"the problem is the material that sits on top of the bedrock. At Rest and Be Thankful this is a comparatively thick layer of colluvium – deposits left from earlier phases of slope instability – and varying amounts of topsoil and peat. These materials are susceptible to failure in heavy rainfall. Unfortunately, as the intensity of rainfall increases due to climate change, and the United Kingdom is getting longer spells of rainy conditions as well, repeated failure is occurring."
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Re: A83 Rest And Be Thankful blocked again

Post by swissferry » Thu Mar 03, 2022 22:55

I'm not expecting one of the tunnel options to be chosen but good to know there have been discussions with the Norwegian Government to learn from their experiences in assessing and building tunnels.

https://www.transport.gov.scot/news/a83 ... sign-work/

A good clear summary:
https://storymaps.arcgis.com/stories/5c ... 7910c68da4

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Re: A83 Rest And Be Thankful blocked again

Post by KeithW » Fri Mar 04, 2022 09:26

Enceladus wrote:
Sun Jan 30, 2022 19:57
Would climate change be partially responsible for all these landslips at Rest And Be Thankful?

The A83 is a critical and vital link between Kintyre and its environs to the central belt of Scotland so addressing this persistent problem with a long-term solution is very important.

Would there be the possibility of a completely new route for the A83 well away from this location?
Possibly but the reality is that landslides on the A83 have been happening ever since it opened in 1941. Its hardly surprising to find high rain fall in western Scotland after all and building a major road across an unstable slope is apt to produce problems.

A study by Jacobs in 2013 put the risk of landslips in the high to very high category. The recommended option of rerouting the road through Glen Croe was not taken and the cheaper option of improving drainage was implemented. It only cost £2 million and didnt work.
https://www.transport.gov.scot/publicat ... -bute-a83/''

From the British Geological Survey.
https://www.geolsoc.org.uk/Geoscientist/Archive/June-2013/2012-Landslide-year wrote: REST AND BE THANKFUL


On 1 August 2012 following a period of heavy rain, a debris flow landslide occurred along the A83 Rest and Be Thankful pass in Argyll and Bute. It was reported that 50 to 100 tonnes of material blocked the road, which was subsequently closed in both directions.

While this may not be a large landslide in a national context, its impacts were disproportionately large. The Rest and Be Thankful Pass lies near the bottom of a slope prone to debris flows that have closed this road frequently in recent years. Its closure means a 55-mile detour for all residents, commuters and businesses in the area, costing the local economy £50,000 a day. The cost of engineering a permanent solution to the problem could be as much as £520 million.

The debris flows occur on steeply sloping ground underlain by the Neoproterozoic Beinn Bheula Schist Formation, comprising very strong metamorphosed psammites and semipelites composed largely of quartz, feldspar and mica, commonly intensely foliated and spectacularly folded. Bedrock plays relatively little part in landslide activity on these slopes, however, and the recent debris flows have largely been associated with slope deposits - including peat, topsoil and underlying colluvium. Colluvium deposits on this slope represent earlier phases of slope instability and comprise sandy to gravelly silts and clays, with varying amounts of cobbles and boulders. It is also likely that conditions were exacerbated by the additional input of water from bedrock pathways, where jointing or fracturing occurs, due to groundwater flux from the heavy rain leading up to the event.
This is a bad place to build a road is my short description.

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Re: A83 Rest And Be Thankful blocked again

Post by jackal » Sat Mar 05, 2022 14:47

KeithW wrote:
Fri Mar 04, 2022 09:26
Enceladus wrote:
Sun Jan 30, 2022 19:57
Would climate change be partially responsible for all these landslips at Rest And Be Thankful?

The A83 is a critical and vital link between Kintyre and its environs to the central belt of Scotland so addressing this persistent problem with a long-term solution is very important.

Would there be the possibility of a completely new route for the A83 well away from this location?
Possibly but the reality is that landslides on the A83 have been happening ever since it opened in 1941. Its hardly surprising to find high rain fall in western Scotland after all and building a major road across an unstable slope is apt to produce problems.
...
This is a bad place to build a road is my short description.
Indeed. While I expect there is an increase in rainfall in Scotland due to climate change it has been minor so far, and is swamped by the 'noise' of yearly variation:

https://www.statista.com/statistics/367 ... -rainfall/

Also, more anecdotally, last year certainly didn't seem like a 'good' year for the Rest And Be Thankful though we had one of the lowest rainfalls in recent decades. The ground conditions are so bad now that they're pretty much a problem regardless.

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Re: A83 Rest And Be Thankful blocked again

Post by KeithW » Sat Mar 05, 2022 18:07

Mark Hewitt wrote:
Sun Jan 30, 2022 19:06
swissferry wrote:I've seen the aftermath of numerous landslips around that area, including one above though not reaching the forest tracks on the other side of the Croe Water. While trees reduce the risk of landslips I have been surprised how far into forested areas they do penetrate. I've seen several in Gleann Leaccann Sheileach (5km to the east of the Rest) which have started above the forest and reached beyond the forest track. From what I've seen I reckon the landslips are closer to a fluid than solid so still flow easily through forest with bigger slips taking the trees with them.
Cheers. It seems a rock shelter would be the most effective then or a tunnel.
a rock shelter doesnt help if the land its built on slides out from under it. At a minimum you would have to drive piles down to bedrock.

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Re: A83 Rest And Be Thankful blocked again

Post by XC70 » Sat Mar 05, 2022 18:30

KeithW wrote:
Sat Mar 05, 2022 18:07
Mark Hewitt wrote:
Sun Jan 30, 2022 19:06
swissferry wrote:I've seen the aftermath of numerous landslips around that area, including one above though not reaching the forest tracks on the other side of the Croe Water. While trees reduce the risk of landslips I have been surprised how far into forested areas they do penetrate. I've seen several in Gleann Leaccann Sheileach (5km to the east of the Rest) which have started above the forest and reached beyond the forest track. From what I've seen I reckon the landslips are closer to a fluid than solid so still flow easily through forest with bigger slips taking the trees with them.
Cheers. It seems a rock shelter would be the most effective then or a tunnel.
a rock shelter doesnt help if the land its built on slides out from under it. At a minimum you would have to drive piles down to bedrock.
If you built a rock shelter nature could then turn it into a cut and cover tunnel.....

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