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General Renewable Topics => General Discussion => Topic started by: chasfromnorfolk on November 15, 2020, 08:08:38 AM

Title: peat bog slippage, Donegal
Post by: chasfromnorfolk on November 15, 2020, 08:08:38 AM
A fairly amazing thing to capture on camera, might provoke discussion... remove gap in address line

https://twitter .com/rooneymobile/status/1327581502763380736

Cheers, on a stormy Sunday, Chas

Title: Re: peat bog slippage, Donegal
Post by: AndrewE on November 15, 2020, 09:44:54 AM
That is quite something to see.  

I am a bit surprised that there is a gradient to drive it though, I guess peat must be able to form a shallow dome over centuries, the sphagnum growing more in the middle as water fails to drain sideways quickly enough, if you see what I mean.

Before it was "reclaimed," Risley Moss, in the Mersey valley (now the Manchester Ship Canal) appartently suffered bog bursts to the extent that black water and dead fish reached the Irish coast.  However I had the impression that it was a very fluid / liquid peat suspension or slurry which escaped.
[Correction: it is mentioned on the Chat Moss Wikipedia page.  I am certain that I have never been there though, and saw it described on a sign board at Risley.)

Title: Re: peat bog slippage, Donegal
Post by: biff on November 15, 2020, 11:14:49 AM
 An engineer once told me that our Irish boys are quite unique and difficult to deal with regarding road building and bridge construction. Nothing is permanent, the bog I always moving.
 Between one rock and another, there could be half a mile of road transversing an apparent level bog, but of course there are stream with bridges and the streams will flow to the river and on to the sea .
  The summer sun and lack of rain does more damage to this kind of road because the bog shrinks and compacts lower, the large10ft concrete diameter pipes that create these bridges also sink. The council will come along and fill the hollows, do  really nice job but within a few years the whole road regresses to its original10 ft deep hollows.
  The tar acts like an elastic band but the stretch Mark's are only visible were the bog gives way to the rocks.
    So yo have this good half mile of tarred road that crosse 2 bridges strung in between two rocky outcrops. 6 weeks of dry hot weather and the bog shrinks and sinks,  the road that slopes up the rocks at either end faces the full glare of the sun and becomes flexible,  then stretch marks appear on the road across the rocks as the road across the bog sinks.
    From what I have notice, as the road gets stretched,  the regular parallel breaks across the road, are approx 100mm with gaps of approximately  20mm stretching for approximately 20mtrs on the road .
  Contrary to what one would expect, say the road would break and expand on the bog easier but no.
  The road over the bog only gets warm on the surface but the road across the rock gets warm quicker because there is less depth and no insulation against the heat. This keeps happening within 3 mile of our house so I have had great opportunities to note and observe. Well  you could not  miss it. Every 3 to 5 years or so, the large pipes that make the bridges are dug up and raised once again. The local drivers know to keep driving at a good pace because if they go slow the road edge will break and the trucks will veer of into the moss.
  The real trouble starts after th 6 weeks of dry, the bog dries out and then sudden prolonged rainfall gets time to float parts of the bog that had become like hard black wood which could take days to absorb the water properly.
   You can be looking at slippage and not realising what it is. It can move so slow and you can see the opening and mistake it for a turf bank or a rough path.
   Not far from here is a area of 3 mts by 50mtrs. The trees are some 30ft high. Years ago when they were about 20ft high, I would walk among them in the dry weather,.
  After weeks of rain , they would become a bit of a nightmare as you walked  among them they dipped and dived until you grabbed one to steady yourself. The whole area was floating. My son and I were a little panicked back the so we went and got our long iron bar and  went and sounded it out to see what was under neath. The deepest part was about 1ft of soil and 4ft of water or mud.
   Underneath was flat rock that extends all over the site and into the bog beyond. So the mystery was solved and afterwards I learned to regard the bog as a living thing that runs it's own show.  I have no scientific  qualification of kind so It's possible that I could be wrong. There is excellent footage of a bog complete with forest coming down a mountain in Mayo, crossing a main road and destroying one of the best trout rivers in that county. It was all named on a road that wa constructed up the mountain to install and service wind turbines. I have blethered enough.

Title: Re: peat bog slippage, Donegal
Post by: chasfromnorfolk on November 15, 2020, 11:33:29 AM
“Unforseen works below ground level” eh, Biff?

Once, we were cutting down to gravel to get a bearing for house foundations... ended up 11 feet down through the peat with a six inch pump going to help. I remember clearly a series of holes through the peat wall, like arteries, at various depths, all pouring water...


Title: Re: peat bog slippage, Donegal
Post by: AndrewE on November 21, 2020, 09:29:05 AM
Further coverage here: 
"Donegal: Ministers shocked at peat slide devastation" which ends
...And the EU is likely to take a dim view of the incident.

It will want reassurances that all proper checks were done before this development was approved given its potential impact on a protected site.

Ireland has already been hit with 10m euro in fines - and rising - over a similar peat slide at another wind farm under construction in Co Galway in 2003.

Title: Re: peat bog slippage, Donegal
Post by: Mudman on November 21, 2020, 10:44:38 AM
... and good post in the landslide blog here:

and about another Ireland peat slip here

Title: Re: peat bog slippage, Donegal
Post by: Ted on November 21, 2020, 10:46:50 AM
This is the 2003 incident -

Title: Re: peat bog slippage, Donegal
Post by: todthedog on November 21, 2020, 11:59:34 AM
Blimey that is scary. Always concerned that another Aberfan might occur insufficient monitoring due to cutbbacks.

Title: Re: peat bog slippage, Donegal
Post by: biff on November 21, 2020, 01:50:09 PM
The scariest thing of all is a bog on top of a lake,
          This is a very common occurrence.
 Once when I went along with a family to lift their turf,  it was just a simple job of driving along the top of the bink  as the family hurled the turf on to the trailer.
 Their tractor was a much prized McCormack International of very good vintage, The governors were set to rev up and down as it sat ticking over, So it would rev to maybe 1000rpm, then shut down but restart just as it was about to die, over and over again.. out on the road it ran perfect.
   There was one rule for both the bog and the beach, you never switched off the engine . Never.
   After a few loads, we called for tea, and left the tractor drumming over about 50ft away while we had our cold tea and Farral Scones.
   We felt nothing for the first 5 minutes, maybe because we were all laughing and joking, but then the whole bink  began to quiver to the up and down revs, It became more than a little uncomfortable till suddenly the driver jumped up and ran for the tractor, leaving us all sitting and telling us to stay and he would be back within the hour.
    When he came back he was towing his trailer with his old T20 TVO which ticked over like a sowing machine. They were days of soft breezes and still heat hazes,  My old man had a Cropmaster  twins front and back, He used a large slipe on the end of a heavy wire rope which was attached to a winch, He would get up to speed and sail along with the slipe tight to the back of the tractor putting the weight on the rear, but when he felt the Tractor starting to bog, he pulled the lever to play out the cable and would re engage the winch once he was over the soft spot,  The problem was, once he got bogged, It was a major operation getting the tractor out. Petrol was dear back then at half a crown a gallon or 2shillings and 6pence. Approx 12 and a half new pence.
   We had a lot of respect for the bog.