Mapping Mountains – Trimble Surveys – Drygarn Fawr

23.05.15  Allt y Clych (SN 978 570), Lan Ganol (SN 973 571), Lan Fach (SN 971 574), Llethr Melyn (SN 959 579), Craigol (SN 979 587), Banc Craigol (SN 983 582) and Cefn Tŷ Mawr (SN 986 576)    

Banc Craigol (SN 983 582)

When visiting five hills amongst the Elenydd two days ago that were centred on Wenallt (SN 933 571) I looked to my east and thought the ridges extending upto and away from Llethr Melyn and Banc Craigol worth investigating.  And so, with the weather set fine for the day I parked beside the B 4358 at SN 983 566 where there is sufficient space for two cars to be left.

From this parking spot a narrow lane heads into the Hirnant valley with hill ridges either side, it would be this valley that formed the centre of my planned horseshoe walk.  As I walked toward Allt y Clych the green slopes of Banc Craigol and the wooded summit of Cefn Tŷ-mawr rose across the intervening valley, both looked good hills and would be the last two I visited later in the afternoon.

The wooded summit of Cefn Tŷ Mawr

I left the lane after a few hundred metres and gained access onto the higher slopes of Allt y Clych through two gates leading across the hill’s lower fields.  Once on the higher part of the hill the views opened up and the ground steepened until I arrived at its attractive summit.  Two spots vie for the highest point, one grassy and one with a small outcrop of rock, I gathered data from both and waited lazily in the morning’s sunshine until the Trimble was packed away.

Gathering data at the summit of Allt y Clych

Between the P30s of Allt y Clych and Llethr Melyn are a number of small bumps, including Lan Ganol and Lan Fach, I surveyed both of these hills including any alternate summit and their respective bylchau, this took quite some time and by the time I reached the path leading upto Craig Chwefri and its trig point I had taken nine data sets.

Looking back to Allt y Clych - I'd taken nine data sets along this ridge

The path leading toward the trig point petered out into hillsides of moor grass and bilberry, away to my west was the forested top of Gornoeth which I had visited two days previously, it felt a little odd being back in this area so soon after visiting a number of its hills, but there are still more to investigate and these southerly approaches to some of the lower hills of the Elenydd are proving pleasantly tranquil.

The summit of Craig Chwefri is part of the slightly higher hill of Llethr Melyn which according to Ordnance Survey data has three summits of the same 433m map height.  As I reached the trig and placed the Trimble to gather data on the highest ground a few metres away from it, I looked out to these three tops of Llethr Melyn and thought the furthest easterly one to look slightly higher, however the human eye is deceptive when judging the lay of land and only a survey would be able to separate them by height.

Gathering data at the highest ground close to the trig point on Craig Chwefri

By now patches of cloud had built in the sky which added light and shade to the landscape, this in time would bring succulent summer greys to the eastern land that was enriched with direct sunlight, this is always a treat and gives a vivid appeal to photography, but this was for later in the day, now I wanted to survey the three tops of Llethr Melyn and shortly after leaving the trig point on top of Craig Chwefri I arrived at the first rocky top.

I checked the ten figure grid reference from the Ordnance Survey enlarged Geograph map and found it directing me to the lower of two rocky outcrops about thirty metres apart, I took data from both and then proceeded to the other two map heighted 433m summits, both of these are on moorland.

Gathering data on the rock that the Trimble data gives as the highest point of Llethr Melyn

Gathering data at the far easterly option for the summit of Llethr Melyn with its connecting bwlch in shadow beyond

Happy that four data sets and an additional one from beside the trig on Craig Chwefri was sufficient I packed the Trimble away and walked along the hill’s easterly ridge, before delving down northward toward the hill’s connecting bwlch with higher ground.

Craigol from the bwlch of Llethr Melyn

After collecting data from two places on the hill to hill traverse on this bwlch I considered that the second part of the walk was nearing its conclusion, the first having been the ridge from Allt y Clych to just beyond Lan Fach, the third and last section would take me over the three P30s of Craigol, Banc Craigol and Cefn Tŷ-mawr.

Gathering data at the bwlch of Llethr Melyn

I lost a little height and contoured through what could have been decidedly boggy ground on a small path that led toward green fields which constituted the highest part of this valley’s cultivation.  Once beyond the fields I joined a track that led to the old farm house of Lluestnewydd where Maj and Stewart Jackson-Carter were busy inspecting their large stone barn’s roof.  I waved as I approached and soon we were in conversation, shortly afterward Maj said some magical words ‘would you like a cup of tea’.  Mmmmmmmmmm heaven on earth does exist!

As Maj went inside to get the tea brewing, Stewart opened the gate and we sat beside their ornamental pool and chatted, when Maj appeared with a tray of mugs full of tea I had to smile and then found it hard to stop.

Heaven on earth - Maj brings the mugs of tea

It was lovely meeting Maj and Stewart, we talked for quite some time about the local hills, their house and its history, the Trimble and surveying, the route I had taken to get here and my onward route back to my car, their meetings with other walkers who occasionally come this way, fox hunting, place-names and probably a multitude of other topics.

With Stewart and mugs of tea at Lluestnewydd

Throughout the conversation I supped on my mug of tea and relaxed and happily smiled away, the tea was an absolute luxury and one that was totally unexpected.  After about twenty minutes I thanked them and we said our goodbyes and I wandered off to continue my route, this time in a southerly direction toward the next three hills.

Cheers - many thanks to Maj and Stewart for my refreshing pit stop.  Allt y Clych is in the background on the right and the summit of Banc Craigol on the far left of photo

The track from Lluesnewydd led toward another farm named Craigol with the right of way swinging leftward to miss the farm yard, this now led me down toward the next bwlch I wanted to survey, this is to the north of the rocky summit of Craigol which sprung up with its upper slopes now showing the signs of felled forestry, but thankfully no re-planting had taken place.

Once I had wandered around in the field where the bwlch lay for a number of minutes and picked the spot for the Trimble to gather its data, I stood and regained by breath for the next ascent up to the unusually rocky summit of Craigol.

Gathering data at the bwlch of Banc Craigol with Craigol on the left and Llethr Melyn in the background on the right

On my way up to the summit I bi-passed a group of cows with their calves that were wandering down the track and stopping for a contented graze, once across a fence I was in the remains of the felled forestry.   The high point of Craigol has a small ridge leading to a steep outcrop of what I thought to be mudstone, all layered on top of itself and looking unusually out of place amongst hills of moor and grassy field.

Llethr Melyn from the summit of Craigol

Gathering data at the summit of Craigol

The next survey was at the bwlch between the summits of Craigol and Banc Craigol, it was also the survey that I was most concerned about as it looked as if it was situated in a filed adjacent to a farm house.  As I arrived at the farm I knocked on the front door with good intention of introducing myself, explaining my unusual surveying hobby, trying to explain what prominence is and the necessity for them to give me permission to survey their field, and who knows I may have ended up with another cup of tea in the process.

Lines of hill and pasture

Unfortunately no one answered so I sneaked around the farm yard, quietly went through a gate and followed a track to where the critical bwlch lay, all in full view of the house.  Once I had picked the spot for Trimble placement I stood beside another gate and hoped that no one would ask what I was doing.  It didn’t help that the bwlch lay just below a grassed bank which interfered with satellite reception, so it took quite some time for the 0.1m accuracy to be attained before data can be logged.  Once complete I quietly retraced my steps and continued up the right of way to the easterly slopes of my next hill.

Gathering data at the bwlch of Craigol with the Trimble beside the fence on the right of photo

Banc Craigol is an appealingly shaped hill with an elongated summit ridge that extends from its grassy top in a south-westerly direction to a slender ridge crest before plunging down through slopes of bracken to the Hirnant below.  As I arrived at its summit the day’s exertions were taking their toll and I gratefully rested as the Trimble gathered its data, only two surveys now remained.

At the summit of Banc Craigol with Llethr Melyn in the background on the left

The afternoon was now enhanced with deep grey cloud out to the east which illuminated the richness of colour with the late afternoon sun in the west, and as I re-joined the right of way down to the next connecting bwlch I stopped and admired a single well shaped tree in a brightly coloured green field as deep colour behind faded into shadow.

Summer colour on a single tree

Once the last bwlch survey was complete I plodded up toward the summit of my last hill of the day, this summit is part of Coed Tŷ Mawr and has the name of Cefn Tŷ Mawr, with the farm that the hill and wood take their name from to the south of the summit, the north-easterly flank and upper part of this hill has an oak wood on it, today the wood was filled with Bluebells and once across a fence I delicately walked up to the large boulder at its high point.

Looking down on the bwlch (on far right) and wooded summit of Cefn Tŷ Mawr

After I had stood on top of the boulder I placed the Trimble with its internal antenna aligned to the highest part of it and then started a long wait.  I suspected this would happen as tree coverage is not ideal for satellite reception.  However, I found a comfortable rock to sit on which was covered in moss and only four paces away from the sides of the boulder, so I could briskly march up to the boulder and step up to check on the Trimble’s downward progress to the 0.1m accuracy level.

The boulder at the summit of Cefn Tŷ Mawr

The initial part of my long wait was welcome as I sat and ate a bean burger that I had cooked the previous day, munched on a couple of sandwiches and immersed myself in the life of the wood as bird song radiated out.  After a while I found that I was studying the colours of the near trees and examining the ground to my north-east which looked horrendously brambled, I had already torn my leg on one of these brambles and caused copious amounts of blood to trickle out of the wound, trying to wipe this with a clump of grass only smothered it all over my leg which now looked as if I had been stabbed!

The view from my mossy rock

Straight lines of green with the balanced colour of Bluebells

After thirty minutes I wondered how much longer I would have to wait and life in a wood began to tax my patience.  After 45 minutes I had lapsed into a contented otherworldly experience as an occasional flash of sunshine penetrated the wood and gave dabbled light to the undergrowth.

I'd been in the wood so long that I started to enjoy the pattern the trees made with the sky

Only the occasional sunburst penetrated the cloud as I waited patiently in the wood

After 55 minutes I wondered if I should at least activate the Trimble and gather data until it screeched, which is the sign that data collection should cease.  I jumped up from my slumber and pressed ‘Log’ and turned the equipment off after it had gathered 133 points which is more that the recommended minimum.

By the time I had taken photos of the Trimble positioned on the boulder I had been in the wood for over an hour, it felt as if I had become a Hobbit.  Re-entering clear skies and sunshine was a welcome relief.

The Trimble on top of the boulder at the summit of Cefn Tŷ Mawr

I walked back down the field toward where the last bwlch survey had taken place and joined a track and then path down through another wood, this led out onto the narrow lane at the base of my first hill of the day; Allt y Clych, which shot up in tapered form.

The shapely profile of Allt y Clych

House sign made out of nails

The walk back on the lane to my car was delightful as the early evening light gave a richness of colour with far away hills being highlighted against a deep mass of succulent grey cloud.

Succulent summer colour

These light conditions only seem to happen in the summer months and give a rare intensity to summer colour which is usually dulled and washed out.  I stood and happily took photos as sheep grazed in their fields and the freshness of early summer growth gave an emerald colour to the trees.

Greens and grays of summer

Richness of Grey enhanced by evening summer light

Before leaving this scene I looked back up toward the wooded slopes of Cefn Tŷ Mawr with the green ridged top of Banc Craigol above, both are excellent hills as indeed is the circuit I had now completed.

Banc Craigol in centre of photo with the wooded summit of Cefn Tŷ Mawr on the right

In all I took 22 data sets and the walk had taken me 9 hr 35 min, which was quite a long time, but I had been invited for afternoon tea on the way and spent an hour sitting in a wood, happy times.    

      

Survey Result:

Allt y Clych

Summit Height:  380.7m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 97829 57012 (Trimble GeoXH 6000)

Bwlch Height:  341.1m (LIDAR)

Bwlch Grid Reference:  SN 97349 57351 (LIDAR)

Drop:  39.6m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  10.41% (Trimble GeoXH 6000 summit and LIDAR bwlch)

Lan Ganol

Summit Height:  375.3m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 97371 57189 (Trimble GeoXH 6000)

Bwlch Height:  351.8m (LIDAR)

Bwlch Grid Reference:  SN 97732 57107 (LIDAR)

Drop:  23.5m (Trimble GeoXH 6000 summit and LIDAR bwlch) (Sub-Trichant addition)

Dominance:  5.25% (Trimble GeoXH 6000 summit and LIDAR bwlch) 

Lan Fach

Summit Height:  365.9m (converted to OSGM15)

Summit Grid Reference:  SN 97161 57461

Bwlch Height:  347.9m (converted to OSGM15)

Bwlch Grid Reference:  SN 97081 57539

Drop:  18.0m

Dominance:  4.92%

Llethr Melyn

Summit Height:  433.0m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 95967 57997 (Trimble GeoXH 6000) (summit relocation confirmed)

Bwlch Height:  394.1m (LIDAR)

Bwlch Grid Reference:  SN 96507 58769 (LIDAR)

Drop:  38.9m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  8.99% (Trimble GeoXH 6000 summit and LIDAR bwlch)

Craigol (significant name change)

Summit Height:  361.0m (converted to OSGM15)

Summit Grid Reference:  SN 97939 58725

Bwlch Height:  327.1m (converted to OSGM15)

Bwlch Grid Reference:  SN 98101 58517

Drop:  33.9m

Dominance:  9.39%

Banc Craigol

Summit Height:  381.0m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 98392 58269 (Trimble GeoXH 6000)

Bwlch Height:  324.1m (LIDAR)

Bwlch Grid Reference:  SN 98037 58938 (LIDAR)

Drop:  56.9m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  14.93% (Trimble GeoXH 6000 summit and LIDAR bwlch)

Cefn Tŷ Mawr

Summit Height:  324.2m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 98691 57665 (Trimble GeoXH 6000)

Bwlch Height:  292.0m (LIDAR)

Bwlch Grid Reference:  SN 98452 57819 (LIDAR)

Drop:  32.2m (Trimble GeoXH 6000 summit and LIDAR bwlch) (Sub-Trichant reclassified to Trichant)

Dominance:  9.94% (Trimble GeoXH 6000 summit and LIDAR bwlch)

For further details please consult the Trimble Survey Spreadsheet