Mapping Mountains – Trimble Surveys – Y Berwyn

19.06.17  Gurn Moelfre (SJ 184 293) only bwlch surveyed, Hen Graig (SJ 176 309), Blaen Trinant (SJ 172 319), Cefn Hir Fynydd (SJ 154 311) and Pt. 432.2m (SJ 163 301)

Blaen Trinant (SJ 172 319)

With the temperature forecast to edge toward 30° I set off early and navigated the narrow country lanes north-east of Llanrhaeadr-ym-Mochnant toward Pantglas Ucha; a farm whose tracks into the hills gave options for parking.  This, and the area around Llanfyllin has drawn me back on numerous occasions of late, the hills hereabouts are mainly green pasture, but are generally steep in nature and shapely in profile, with the whole area quietly nestled in beautiful landscape.

My first objective was to survey the critical bwlch of Gurn Moelfre; one of the most distinct hills in the neighbourhood.  LIDAR data gives this hill’s bwlch on the narrow lane to the north-west of its summit.  Leaving my car I walked down the lane toward the bwlch as Comins and Moel y Gwelltyn; two hills I’d visited less than two weeks ago, looked down from across the valley, both hills have a striking profile and they looked welcoming in their greened summerness with a foreground of sheep whose morning slumbers had been disturbed as I’d passed.

Gurn Moelfre (SJ 184 293)

The shapely profile of Comins on the left and Moel y Gwelltyn on the right

All was quiet at the bwlch as I set the Trimble up, a long wait then developed, one of the longest I’ve had to endure as it took 40 minutes for the required 0.1m accuracy level to be attained before data should be logged.  I found this slightly wearisome as I wanted to gain height before the heat of the day hit.  I checked the equipment every five minutes hoping that the magic 0.1m would be finally showing, during this long wait two cars passed, each I flagged down and waved around my rucksack, the drivers must have wondered what on earth I was doing as it was barely past 8.00am.  I spent much of the time in thought, letting my mind wander to weird and wonderful places, occasionally I would look and concentrate on the mature trees either side of where the Trimble was positioned, they were marvellous things, huge and dominant with luxuriant green leaves edged in the morning’s sun, a dragon fly flew past and I watched it zigging and zagging to and fro, up and down the lane and into the hedgerow and near trees.  The Trimble reached 0.11m accuracy and I thought it would only be another two minutes before the 0.1m mark was attained, unfortunately the accuracy level bounced back up and I almost gave up the whole process, but thankfully I persevered as a few minutes later the magical 0.1m showed itself and I quickly pressed ‘Log’ and hoped that no other cars would appear in the next five minutes, thankfully none did and once five minutes of data were stored I proceeded on a track leading toward Hen Graig; my first hill of the day.

Gathering data at the critical bwlch of Gurn Moelfre

Dappled light

Even at this relatively early hour the sun beat down, I’m prone to flake out when it’s too hot and I’m on the hill, and have experienced times when I’ve wobbled and felt ill due to excess heat, so had come well prepared with four litres of water.  However, as I slowly made progress up the track bending itself around the western slopes of Hen Graig the heat smothered me, and with hardly a breath of breeze it felt like continental Europe was visiting the Welsh uplands for the day.

Pt. 432.2m (SJ 163 301) from the ascent of Hen Graig

Leaving the main track until later I followed a fence line and green track over the connecting bwlch which I planned on surveying on my way down and slowly plodded to the small rocky knoll at the summit of Hen Graig, I’d visited this summit once before in July 2003 and had then connected it up with the other hills I planned on visiting today, but had approached them from a different direction.

Gathering data at the summit of Hen Graig

Leaving the summit I retraced my route back through copious amounts of thistles to the connecting bwlch and used LIDAR data to zero in to the critical point.  As the Trimble gathered its allotted five minutes of data I sat on the earthen bank attached to a fence and rested.

Gathering data at the critical bwlch of Hen Graig

The track I had used on my ascent continued from the area of the bwlch toward the summit of Blaen Trinant, a hill I had previously surveyed using my old wooden staff.  Away in the distance a screeching sound of a tractor floated across the land, I eventually spotted it busying itself on a steep slope.  All around the lushness of summer enveloped the land with green growth seemingly having no bounds, sheep tried in vain to keep in shade prostrate on rutted tracks until disturbed by my approach.  Bulbous cloud sprang up, a greyed white with a hazed blueness to the sky washing out much of the colour, the land slept, still and sombre, quiet in a heat haze.

Leaving the track I headed toward the summit of Blaen Trinant which consists of grazed grass beside the debris of a few breeze blocks.  A constant companion during the early hours was the profile of Gurn Moelfre, it peered down upon proceedings with an almost disdainful look, with its height and shapely outline giving it dominance upon its immediate land.

Gathering data at the summit of Blaen Trinant

Although I’d paced myself and due to the surveying, rested frequently, the heat was piercing and sweat glistened from every pore as I walked down to another rutted track where the critical bwlch of Blaen Trichant is positioned.  I soon had the Trimble set up and gathering data.

Gathering data at the critical bwlch of Blaen Trinant

By now I was starting to wilt and although I had thought of also visiting Garnedd Wen I decided to evaluate the time and how I felt after reaching the high road where the bwlch of my next hill; Cefn Hir Fynydd is placed.  The track I was on forms a part of the Upper Ceiriog Way, and this section led across the upper northern side of Cefn Hir Fynydd, this hill is elongated and its summit was ahead of me shimmering into view, by now I rested at each fence junction where a gate gave further access on the track.  I left the track to step over a dilapidated and rusting gate to gain access to the long grassed summit ridge, this I followed using the grid reference produced by Aled through his analysis of LIDAR data to take me to the high point, this proved to be at the far end of the ridge, by the time I arrived at the high point I needed a rest.

The grass proved so long I flattened it at the summit to give the Trimble a better chance of satellite reception, and once activated I stood back and waited until the customary five minutes of data were gathered.  Just below me a gate gave access back onto the track which led down to the high road where the critical bwlch of Cefn Hir Fynydd is placed, again the grid reference produced by Aled’s analysis of LIDAR data took me to the point where data should be logged, thankfully the convenience of a fence post meant that I could set the Trimble up at this grid reference giving it elevation above its immediate surrounds and also safeguarding it from cars that may come this way.  As data were collected I considered my onward route, I had planned on visiting Garnedd Wen, a hill I had not visited before, and surveying its bwlch summit and the critical bwlch of Mynydd Mawr which is placed further up the narrow road from where I now was.  However, I knew the heat was taking its toll and I was beginning to flag, I looked up toward the land leading to Garnedd Wen and deciding that this hill could wait for another day I packed the Trimble away and followed the narrow road down south-eastward toward Pant-y-maen farm, by the time I arrived it felt as if the whole land was baked in heat as a stillness pervaded all.

Gathering data at the summit of Cefn Hir Fynydd

Gathering data at the critical bwlch of Cefn Hir Fynydd

Garnedd Wen, too hot and too far for me today

I knocked at the door hoping to make place-name enquiries as the last hill of my walk stood steeply above the farm and is unnamed on Ordnance Survey maps, no one was in.  I called out as I walked through the farm yard wondering if someone was working in an outbuilding, again, no response.  Before heading toward the green track leading from the farm yard to the bwlch of this hill I stopped at a water trough where the gentle sound of cascading water flickered in the sunlight, I spent time cupping handfuls of cooling water and splashing it over my face, within a few minutes of leaving the farm and wandering up the green track, my face was dry.

A well needed refreshing break

The bwlch of the last hill proved a blaze of green and having assessed the lay of land I took two data sets, both near one another before packing the Trimble away and slowly gaining height to another track that led up the steepening slopes of this last hill.  I stopped frequently to regain breath and wipe sweat from my brow.

Gathering data at the critical bwlch of Pt. 432.2m

The high point was in a grazing field and as the Trimble gathered data I stood back and savoured the view and the imminent prospect of getting back to my car to change into dry clothes and get my walking boots off. 

Gathering data at the summit of Pt. 432.2m

Heading down the field I spotted a vehicle track through the grass that led to a gate which gave access on to the track where my car was parked, it was only a short route down and one that I took slowly, arriving at the car was a pleasure and getting my boots off more so. 

Survey Result:

Gurn Moelfre

Summit Height:  523m (spot height)

Summit Grid Reference:  SJ 18445 29388 (hand-held GPS via DoBIH)

Bwlch Height:  289.5m (converted to OSGM15)

Bwlch Grid Reference:  SJ 17806 29915

Drop:  234m

Dominance:  44.65%

Hen Graig

Summit Height:  433.0m (converted to OSGM15) 

 

Summit Grid Reference:  SJ 17668 30905

Bwlch Height:  392.9m (converted to OSGM15)

Bwlch Grid Reference:  SJ 17457 31308

Drop:  40.1m

Dominance:  9.27%

Blaen Trinant

Summit Height:  442.2m (converted to OSGM15)  

Summit Grid Reference:  SJ 17253 31962

Bwlch Height:  416.8m (converted to OSGM15)

Bwlch Grid Reference:  SJ 16857 31848

Drop:  25.5m (400m Sub-Pedwar status confirmed)

Dominance:  5.76%

Cefn Hir Fynydd

Summit Height:  464.6m (converted to OSGM15) 

 

Summit Grid Reference:  SJ 15499 31174

Bwlch Height:  411.7m (converted to OSGM15)

Bwlch Grid Reference:  SJ 14575 30922

Drop:  52.9m

Dominance:  11.38%

Pt. 432.2m

Summit Height:  432.2m (converted to OSGM15) 

 

Summit Grid Reference:  SJ 16375 30157

Bwlch Height:  357.9m (converted to OSGM15)

Bwlch Grid Reference:  SJ 16231 30803

Drop:  74.4m

Dominance:  17.20%

For further details please consult the Trimble Survey Spreadsheet