Saturday, 2 November 2024

Mapping Mountains – Trimble Surveys – Esgeiriau Gwynion

 

26.08.24  Mynydd St Ioan (SH 979 202), Mynydd St Ioan (SH 973 202) and Pt. 503.5m (SH 959 199) 

Mynydd St Ioan (SH 979 202)

The land above Llyn Efyrnwy can be an unremitting place to visit, with miles of pathless moor where heather predominates.  The hills within this land are not distinctive, with many no more than rounded bumps on a seemingly never ending ridge.  I’d visited many of these hills over the years, and always come away with a feeling of it being a wild area where few people outside of local farmers and an occasional hill bagger venture.  Although many are indistinctive; the hills are usually tranquil affairs, with no more than scattered sheep and birds of prey as company.

Today I was out with Aled, who wanted to visit and survey part of Mynydd St Ioan, whose main summit forms the last major hill on the broad ridge that takes in the land on the southern side of the reservoir.  All of the lower slopes, both north and south of this lake are forested and it was a forest track that would take us up on to the open moor.

We met at a large parking area adjoined to a picnic site close to the house of Llechwedd Du.  Before starting our walk we took both cars further west and left one at the end of the track that descends from Hafod Fudr.  This would be waiting for us after our descent.  We then drove back in the other car to the picnic area and started our walk.

It was good to be out with Aled, who I hadn’t seen for a number of months.  Walking on the paved road toward the main access lane to Llechwedd Du gave a semblance of easy walking before the uphill started.  The lane leading to the house had two tangled clumps of ivy cascading down from tree branches overhead.  It was more reminiscent of what may be encountered in a rain forest rather than the quiet surrounds of this part of Wales. 

Looking down and across Llyn Efyrnwy

Beyond the house we were soon on rutted forest tracks that led up toward an easier gravelled track that in time brought us to the gate giving access on to the moor.  Overhead the sky was grey and ominously so with specks of wind-blown drizzle falling.  This was only slight, but in time on the hgher tops would bring a chilled feeling to hands and eventually turn to rain. 

The rutted and very muddy forest track

The underfoot conditions were never difficult, but were mainly pathless, with only a semblance of a sheep path found.  We headed toward a prominent boncyn via the first of the days bogs.  These proved a slushy affair with lots of standing water interspersed amongst the greenery of such places. 

Heading toward the hills

Contouring the higher slopes of the boncyn brought us directly beneath our first hill of the day.  This is the one Aled wanted to survey as LIDAR gives it just over 500m in height with just over 10m of drop, both are qualifications for P10 sub status that accompanies the main Welsh Highlands – Uchafion Cymru list.

The ten figure grid reference produced from Aled’s LIDAR analysis brought us to its high point, and within a few minutes I had reacquainted myself with the workings of the Trimble and it was sitting atop my rucksack gathering allotted data. 

Gathering data at the summit of Mynydd St Ioan (SH 979 202)

I found the view from here amazing.  It consisted of ridge upon ridge of moorland hills and all today bathed in grayness.  Such views are heart warming and especially so when having been away from the hills for awhile.  What amazed me more than anything else was the openness.  It was uplifting to be here, both physically and mentally.  Such places are to be savoured.

After the Trimble was closed down we headed further west to its connecting bwlch with the main summit of Mynydd St Ioan.  Finding a relatively dry area to place my rucksack with the Trimble on top of it proved a difficult procedure as the ground was laden in bog. 

Gathering data at the bwlch of Mynydd St Ioan (summit at SH 979 202)

I now had a chose; continue on the ridge with Aled or descend our inward route back to my awaiting car at the picnic area.  The main summit of Mynydd St Ioan looked tantalisingly near, and the route beyond didn’t look to bothersome on the map and the planned route down also looked good, so on we went.  This meant that Aled would curtail his route which he had planned to include Mynydd Coch and another hill beyond before descending toward Hafod Fudr.  This would have been a wild walk to do and especially so in the weather conditions we were now encountering, as when we crested the upper part of the next hill we had views farther west toward what would be the higher Aran, but all were bathed in a grey murked mass signalling rain heading our way.  Thankfully our part of the ridge was never under cloud and the greyness and rain added an unusual quality to the walk as it emphasised the bleak, but beautiful nature of these hills and the land they are situated in.

We didn’t survey the main summit of Mynydd St Ioan, as LIDAR would suffice.  I had visited this hill before in November 2006 ascending from the south via the farms of Maes-y-carneddau and Cefn-coch.  On that day I also included Pen y Ffridd Cownwy.  The weather then was similar to today; grey and bleak, but without the drizzle and rain.

Descending to another bog enshrouded bwlch we pressed on up the slopes of another small bump that LIDAR gives as just failing to meet P10 sub status.  This would be our final surveying objective and again the ten figure grid reference produced from Aled’s LIDAR analysis brought us to its high point.  The Trimble was soon set up gathering data. 

Gathering data at the summit of Pt. 503.5m (SH 959 199)

Leaving the summit the first vestiges of the promised finer weather emerged from above as glimpses of brightness amongst the swirl of grey cloud could just be seen.  We were soon at the bwlch.  Here I noted the LIDAR position before using the Trimble as a hand-held device to zero in on its critical point.  During this bog trot, Aled headed up to the next bump on the ridge.  By the time he’d visited its summit and headed back down the Trimble had done its stuff and allotted data were gathered and stored. 

Gathering data at the bwlch of Pt. 503.5m (summit at SH 959 199) 

Leaving the area of the bwlch

Heading down toward Hafod Fudr

All that remained was the descent to the awaiting car below.  We followed a green runnel beside a bog enclosed steam as it slowly left the upper bwlch on its downward journey to flow in to the Hirddu Fach.  The slopes soon steepened before we joined a green track leading down to a bridge and then the slight up hill leading to sheep pens adjoined to the remains of the old house of Hafod Fudr. 

The old house of Hafod Fudr

Hafod Fudr

This old dwelling is placed at the meeting of the Hirddu Fach and Hirddu Fawr and must have been a remote place when inhabited.  Just beyond I rested next to a large Ash tree, sitting down to take my one skin jacket off as the conditions were now verging on being barmy.  Looking down to the stream all I could hear was the rustle of breeze as it skimmed across the land and the rather welcoming echoes of falling water as the stream tumbled its way down toward the reservoir.  It felt good to be out in such a place. 

Clumps of wet moss gave a tranquil scene on the descent

The track soon led us back to Aled’s car, passing on the way a large canopy of succulent moss with droplets of water cascading from it.  We stood and looked at this for a minute or so, I’d seldom seen such a thing.  The car proved a welcoming sight after hours on the moor. 

 

Survey Result: 

 

Mynydd St Ioan

Summit Height:  499.6m (converted to OSGM15)

Summit Grid Reference:  SH 97938 20254

Bwlch Height:  489.1m (converted to OSGM15)

Bwlch Grid Reference:  SH 97773 20223

Drop:  10.5m

Dominance:  2.10%

 

 

Mynydd St Ioan (significant name change)

Summit Height:  512.9m (LIDAR)

Summit Grid Reference:  SH 97379 20286 (LIDAR)

Bwlch Height:  489.1m (LIDAR)

Bwlch Grid Reference:  SH 96246 19964 (LIDAR)

Drop:  23.8m (LIDAR)

Dominance:  4.64% (LIDAR)

 

 

Pt. 503.5m

Summit Height:  503.5m (converted to OSGM15)

Summit Grid Reference:  SH 95985 19925

Bwlch Height:  494.4m (converted to OSGM15)

Bwlch Grid Reference:  SH 95867 19927

Drop:  9.1m

Dominance:  1.80%

 

 

For further details please consult the Trimble Survey Spreadsheet

 

 

 

 

 

 

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