Month-old landslip on A816

[wrinkly]

I was unaware of this until I saw this Guardian item just now.

https://www.theguardian.com/uk-news/202 ... h-landslip

Teacher now travelling by boat to educate children at two different school sites on either side of impasse
Donna Ferguson
Thu 2 Nov 2023 23.42 GMT
Last modified on Fri 3 Nov 2023 00.00 GMT

Businesses in a remote peninsula of Scotland are fighting to survive and children are unable to attend their local school nearly a month after record-breaking rainfall caused a severe landslip, which cut off a vital road link to the wider peninsula.

The Craignish peninsula in Argyll was battered by heavy rain in early October, causing a landslip on the A816 near Ardfern which left 6,000 tonnes of debris covering the road and rendered it impassable.

Weeks later, it is estimated that more than 4,000 tonnes of the debris still remains on the road, blocking the peninsula’s access to its nearest town, Lochgilphead.

Local people still face weeks of disruption as a result of the landslip, with some primary school pupils who live outside the peninsula unable to get to their school. Their teacher is having to travel by boat to spend time with them at another school site.

Road access to the rest of Scotland is available from the north, with drivers having to take a long, 90-minute route round to reach Lochgilphead.

Businesses in the area say they are facing a “fight for survival” with many still feeling the effects of the Covid-19 pandemic and the cost-of-living crisis.

A group led by a charity, the Craignish Community Company, is vowing to do all it can to help businesses get through the disruption.

[KeithW]

More details with photos here, its going to take a while especially as its still raining.
https://www.argyllshireadvertiser.co.uk ... ed-2/#null

I suspect that this will be months not weeks to get it stabilised and cleaned up.

[Glen]

The A816 had also been closed further north at Kimelford, where the bridge in the village had been damaged by floodwater beyond repair.
It was fortunate there was a stock of suitable precast culvert sections in a yard in Inverness, for such eventualities in Highland, which Argyll and Bute were able to make use of to get a permanent reinstatement in place promptly.

https://www.argyll-bute.gov.uk/news/202 ... 1-november

[TomJ]

Diversion route due to be in place for mid-December. Work is continuing to clear the debris, but the hillside is still considered unsafe however.

[rileyrob]

It's not that local to here, but local enough that we're hearing that the council are putting in a temporary road with a view to making it a permanent realignment in the new year. In the short term it sounds like it will be a forest road type construction operating under convoy system, and built to take service buses and smaller lorries, but not fully laden artics (mostly timber lorries). They hope to have it open a couple of weeks before Christmas, which is good going when you consider the terrain they are dealing with - for instance this is where it will apparently start.
Although the old road is proving to be surprisingly intact under all of the debris, the instability of the slope above is a serious concern, and the original hope of clearing the road by the end of November is gone. We've heard that more material is trickling down after they clear below and until the vegetation starts to bind it together again they are doubtful of being able to open the road safely.

Local hauliers are asking for the opportunity to be taken to completely rebuild the road, bypassing Kintraw Bridge and the difficult bends climbing up the hill. I doubt that Argyll have the money for this, but under the circumstance it may just be possible.

[jnty]

There appears to be a track there already. Is it actually an old alignment of the road?

Sabre maps suggests that half of it is: https://www.sabre-roads.org.uk/maps/ind ... p&layer=33

with NLS maps clearing up the picture a bit: https://maps.nls.uk/geo/explore/#zoom=1 ... rs=175&b=1

[rileyrob]

Argyll & Bute Council are hoping to open the emergency diversion route tomorrow: https://www.argyll-bute.gov.uk/my-counc ... 6-landslip

[wallmeerkat]

How will working under convoy work? I assume it's probably no different to temporary traffic lights reducing a road to one lane, but does "convoy" assume that there will be a works vehicle at the head of traffic? Will this be 24 hour?

[Helvellyn]

How will working under convoy work? I assume it's probably no different to temporary traffic lights reducing a road to one lane, but does "convoy" assume that there will be a works vehicle at the head of traffic? Will this be 24 hour?

That made me wonder so I Googled "convoy vs lights" and the first result was a SABRE thread on convoys:
viewtopic.php?t=39662

The main thrust I got from it is that convoys allow works to occupy more space, since the speed of traffic through the works can be much better controlled.

[jnty]

I get the impression convoy working is also favoured for very long sections where people might otherwise assume the lights were broken (and failure to comply would be very disruptive.)

Convoy working on Highland roads is sometimes also timetabled; ie. essentially an intermittent closure. This allows ad-hoc works to take place which would otherwise foul the carriageway. If there is further landslip risk, the convoy driver can monitor this, stay at an appropriate speed, and immediately stop traffic if one is discovered or suspected to be imminent.

I understand that some key trunk road 'closures' for resurfacing etc. maintain the ability to allow eg. emergency vehicles to get through under convoy. You can imagine that this closure might pretty much work that way overnight, with the road essentially closed but the occasional vehicle allowed through as they appear.

[wallmeerkat]

How will working under convoy work? I assume it's probably no different to temporary traffic lights reducing a road to one lane, but does "convoy" assume that there will be a works vehicle at the head of traffic? Will this be 24 hour?

That made me wonder so I Googled "convoy vs lights" and the first result was a SABRE thread on convoys:
viewtopic.php?t=39662

The main thrust I got from it is that convoys allow works to occupy more space, since the speed of traffic through the works can be much better controlled.

Thanks for linking that thread, one post had a video that showed it in action - viewtopic.php?p=1018651#p1018651

Couple of interesting questions - are the traffic lights on manual control? If you're approaching the end of the convoy and the light is green, can you join? Is it 24 hour? If so, does the lead vehicle driver get a break? Does the lead vehicle get refuelled?

I've never really encountered such, NI roads service are fond of just closing a road for months on end 9.30am-4.30pm (eg Moneyreagh Road).

[rileyrob]

There's now an amber warning for a months worth of rain to fall on Sunday. It covers Northern Argyll, which may or may not cover this bit of the road, but it seems likely that there will be a lot of rain in the area anyway. Lets hope the temporary road is able to operate without another blockage on the route.

[rileyrob]

Finally got some dry weather to go and take a look today. The temporary road is single track, with a passing place midway (next to and opposite large gravel hardcore areas for contractors to park in). In the hour-ish I was there this morning, only 11 vehicles went through the convoy system, which requires a truck to be parked at either end with a person in it on a radio and then a van shuttling back and forth. I was aware of three occasions that the van was at the wrong end. They didn't turn the signals to green either, they just seemed to presume that the sight of the convoy van moving off (and maybe a wave from the parked truck) was enough. Surely the convoy can't be run 24/7 when traffic volumes might be down to a couple of vehicles an hour!
I know from local hauliers etc that the council has requested that artics / vehicles over 26T do not use the temporary road, but there was no signage, so this request presumably isn't backed up by a weight limit or anything (yet).

The old road has been cleared but had a stream flowing down it, and there is still a lot of debris residue around the base of the landslide.

I think that there is a way to create a completely new alignment without damaging the archaeology, except that Kintraw Bridge would probably be lost. A new bridge on a gradient and long skew would allow a road to run up the side of the burn and into the forest. There would probably need to be an embankment and cutting to get the gradient right, but I think it could be done, and might be cheaper than the long term management of the slope. It would also remove the narrow twisty bends of the current alignment. A lot of money has been spent on the A816 in the last few years as a Strategic Timber Route, so if the prospect of removing the (lovely) listed bridge can be overcome, or if the old bridge could be bypassed and left, then half a mile of new road might get built.

[rileyrob]

Photos uploaded here: Gallery:A816/Kintraw Landslide
The Landslide / work site is not fenced off, nor are there any warning signs surrounding it but I'm not sure how far right to roam applies in the area.

[Summers-lad]

Very interesting photos. Do you think the temporary diversion could be converted to (part of) a permanent one - with widening obviously - or would it need to take a different line again?

[rileyrob]

I don't have any direct contact with Argyll & Bute council, so I can't give a definitive answer, but based on the conversations that I have heard / my boss has been involved in, I think that the preferred option is for a susbstantial length of new road to bypass a number of issues in the area.
Firstly the tight bends climbing up from Kintraw Bridge
Secondly the Landslide area itself and
Thirdly the narrow viaduct section higher up.

The two older issues have long been problematic for hauliers, and many of the other tight bends on the route have been improved to some extent as part of the Strategic Timber Transport schemes, which has seen long sections of the A816 widened, and subtly realigned in recent years. For instance These bends have been opened up in the last 2 years, and while the road is not now straight, a large part of the hillside has been cut back as can be seen on the satellite view (and in my photos which I need to upload). I think therefore that between the STT funding and the Central Government funding that A&B has received already to deal with the landslide issue, there will be a lot of work progressing to find a completely new alignment, as alluded to in my post above.

The road currently climbs from more or less sea level to 115m in about a mile, which means that a shorter routing is likely to increase the gradient to around 1 in 10. I think that the bends and the landslide area could be bypassed, probably at the expense of Kintraw Bridge, with the new line coming into the temporary bypass roughly where I took my photos at the edge of the forest. The viaduct section will be harder to bypass, as it passes through the steep and narrow Bealach Mor, but the carriageway is narrow, and the viaduct itself is probably approaching 100 years old, so it may become necessary to replace it soon anyway. Doing this online without a lengthy road closure might be possible (as at Pulpit Rock on the A82) or it may not.
The only alternative that is obvious on the map is the steep climb alongside the burn up towards Lochan na Goirt and then curving back through the forest. This looks to be a steeper climb that the current road, however, and would probably have a ruling gradient steeper than 1 in 10 unless a snaking ascent could be worked in, crossing the burn more than once.
If funding was available for three miles of new road, perhaps continuing along the coast and then following the Eas Mor through the forest to Carnasserie Castle could be achievable.
This is an archaeologically rich area, however, and any local realignment at Kintraw will pass close to a group of Cairns and a Standing Stone above the existing tight bends, two hill forts, and probably numerous other sites not identified on the maps

[Glen]

Some photos of the area and temporary diversion road.