Mapping Mountains – Trimble Surveys – Esgair Wen

25.06.18  Bryn y Crofftau (SN 748 634), Carn Fflur (SN 746 623), Pt. 512.8m (SN 747 620), Pt. 516.9m (SN 754 620), Pt. 526.8m (SN 745 611), Grug Crofftau (SN 750 612) and Llethr Brith (SN 756 614)

Bryn y Crofftau (SN 748 634)

The Yr Uchafion list of Welsh P15 hills over 500m in height opens up a number of places amongst the hills, where their P30 counterparts aren’t necessarily well represented and the land to the south-east of Pontrhydfendigaid is one such place.

I’d only visited the hills in this area once before and on that day found a number of forest rides  and tracks not marked on the 1:25,000 Explorer map, with the forest rides giving relatively easy access to a number of 500m P15 summits, albeit with the underfoot conditions being rather tough.  Since that day the Ordnance Survey Interactive Coverage Map hosted on the Geograph website is now available online and this map shows many spot heights applicable to these hills that do not appear on any other publicly available map, resulting in summit relocations and new Uchaf hills.  It was this area that Aled suggested we should visit and he had plotted a route between seven hills and supplied aerial maps and grid references and I then added a number of other grid references if we had the opportunity to extend the walk.  

We met in the outskirts of Machynlleth and took one car to Ystrad-fflur (Strata Florida) where we set off walking at just before 8.30am, even at this hour the heat pervaded the land and with a forecast for 30º temperatures in the country we knew it was going to be a very hot few hours on the hill.

Following a track in to the lower grasslands of the Elenydd the land resembled southern France or parts of Spain, with blue skies above and all-pervading heat cascading down with dry and dusted pathways.

Heading to the hills

Finding our route to the forest track

Our first planned hill was Bryn y Crofftau which is listed as a Pedwar, to get to it we needed to find the forest track that I had used as my descent route when last on these hills.  Our inward route led to beautiful mixed woodland and eventually down on a minor track to the main forest track which forever gained height and brought us to a clearing to our north-east, which gave access to Bryn y Crofftau.

The gap in the trees leading to the summit of Bryn y Crofftau

Leaving the forest track a narrow path led down to a boggy area and continued through thick rough summer grass toward the summit, even at this stage I began to wilt through the heat, it was debilitating and even more so with the realisation of what land we were planning on visiting and the underfoot conditions we would encounter, however Aled had brought the remains of last night’s Chinese take-away and two spare ribs shared between us seemed to rejuvenate me whilst the Trimble gathered its allotted summit data.

Heading toward the summit of Bryn y Crofftau

Gathering data at the summit of Bryn y Crofftau

Retracing our route back to the forest track it then led us up to large swathes of land that had been felled of conifers and which thankfully had not been replanted.  Our next hill was Carn Fflur and its ancient large cairn; now clear of forestry this vantage point gives excellent extended views.  The ancient cairn measures 25 metres in diameter and two data sets were taken, one from its rim and the other from its hollowed centre, during data collection the heat beat down.

Carn Fflur (SN 746 623)

Gathering data at the summit of Carn Fflur

The connecting bwlch between this and our next hill was again clear of forestry and the customary data set was taken before we made our way to the summit of a 513m map heighted hill that is listed as an Uchaf and only just misses out on Pellennig status.

Pt. 512.8m (SN 747 620) from the slopes of Carn Fflur

Gathering data at the critical bwlch of Pt. 512.8m

As data were gathered from its high point I was wilting under the intensity of heat which was proving merciless, and worried on how much more my body could take as I’ve experienced a number of unpleasant incidents either on the hill in Britain or whilst trekking abroad where severe heat has caused my body to succumb in a complete and unwelcome way.

Gathering data at the summit of Pt. 512.8m (SN 747 620)

Our next hill was immersed in forestry and we wanted to survey its summit and connecting bwlch, this hill is only given a single ring contour on contemporary Ordnance Survey maps but has 15m of drop on the Interactive Coverage Map hosted on the Geograph website, and it was one of the hills I had not visited during my previous bagging raid.

Pt. 516.9m (SN 754 620) proved a hot and difficult hill to reach its summit

Leaving the summit of the 513m map heighted hill we re-joined the forest track for a short distance before entering a land of high soft tussocks and bog that led beside the conifers to a forest ride that led up and intersected with another ride, I was now almost on my last legs and needed to stop frequently, hunched over gasping for breath in the incessant heat, I did not feel good at all.

The forest ride leading to the summit of Pt. 516.9m (SN 754 620)

We eventually reached the high point of the wide forest ride and I set the Trimble up to gather data and joined Aled in the shade, getting here was like stumbling in to a trap, and one where I did not know if I had sufficient energy levels to get myself out of.  Thankfully we were on the summit of this hill for about 30 minutes which gave me time to recover.

Gathering data on the summit area of Pt. 516.9m (SN 754 620)

During the walk we had been plagued by copious amounts of horse flies, flies and masses of midges that were buzzing us in swarms and whilst sitting next to Aled in the shade as the Trimble beeped away gathering its latest data set I looked at my scratched and torn legs as flies feasted on my blood, there were so many of them that it hardly served purpose to flap them away, as more only descended, I then felt a stinging sensation at the back of my left leg that increased in intensity to the point that I started flapping about; I had been sitting in a nest of red ants and they had defended their territory injecting their toxic alkaloid venom, they had my notice and I stood up quickly and left them to their nest as my leg turned red and itched in a most unusual and uncomfortable way.

Once data were stored and the Trimble packed away Aled wanted us to survey the hill’s connecting bwlch, which led us down to a land were few could have ever ventured in to, it was prehistoric in nature with trees covered in shining mosses highlighted in the flashes of sunlight that penetrated the canopy, the floor of this land consisted of bulbous mosses and pine needles which had probably laid undisturbed ever since the forestry was last planted, it was wondrous to be in such a place.  We used the Trimble as a hand-held device to zero in to where the spot height appears on the map and then judged where the best and most convenient spot to gather data was positioned.  During data gathering I rested and slowly regained strength and a willingness to continue living.

Immersed in the conifer plantation

A land of mosses where few could have visited since the forestry was last replanted

Aled navigated us out of the conifers and back on to the forest ride that we had used to gain the hill’s high point, we then regained height back to the forest track that was now beginning to take on the mantle of a long lost friend.

Back on the forest track looking toward the hill we had just visited

Four hills had now been surveyed and we had another three that we hoped to Trimble, this meant pushing further south in to the ever wilder landscape that constitutes the high Elenydd.  We now had two bylchau to survey before our fifth summit, the next point being the critical bwlch adjoined to our third hill; Pt. 513m.  Aled had looked at the 5m contours on OS Maps and the lowest point on the hill to hill traverse at this next bwlch is not at the end of the forest track where the 497m spot height appears on contemporary Ordnance Survey maps.  To get to the critical bwlch we followed a narrow path on the crest of a small ridge that proved delightful to walk after an hour or so immersed in thick conifer plantation.

One of the best parts of the walk heading toward the critical bwlch of Pt. 512.8m

I hoped at this stage that I would be able to complete the walk as I had major doubts only an hour or so earlier, and realised that the rest at the summit and bwlch of the last hill, with both being in shade had helped tremendously.

Pt. 526.8m (SN 745 611) now confirmed as a new Uchaf and Pellennig hill (and subsequently deleted due to LIDAR bwlch analysis)

We chose the set-up position for the Trimble at the bwlch and sat in shade whilst it collected data, Aled now found that the clump of soft undergrowth he was sitting in was infested in another ants nest, they were all over the land as were an incessant plague of flies that followed us for hours buzzing our heads and feeding on my scratched and bloodied legs.

Gathering data at the critical bwlch of Pt. 512.8m

The next bwlch was one of the more important to survey as it is adjoined to Grug Crofftau which is listed with 28m of drop and therefore is a candidate for P30 Twmpau and Dewey status.  When Aled led us in to the bog infested bwlch using the Trimble to zero in on where LIDAR places its critical point to lie, I followed willingly with part of my strength regained.

As I sat in shade beside a dried bog listening to the quiet beeps of the Trimble as it gathered individual data points, I rested, my body felt as if it had been hammered by the heat but I would not have been anywhere else at that very moment in time, as there was a fulfilling element to this walk and the land it took us in to.  During data collection Aled headed off to visit Garn Gron to the west which rose above us with grassed sides that had thankfully never been forested.

Gathering data at the critical bwlch of Grug Crofftau

I closed the Trimble down and excited the confines of the bog and forest laden bwlch at the same moment that Aled headed down from the hill, we were now out of the vast forest on its southern periphery and used the boundary fence to make progress toward our next hill which is currently unclassified but is a candidate for both Uchaf and Pellennig status.

Out of the forestry to its south

The boundary fence led toward a large bog which was thankfully relatively dry and once over it we continued back in to felled forestry and up the southern slopes of the next hill which is given a map height of 527m.

I slowly made progress up its southern slopes, following Aled, there was now a realisation that we were going to complete the walk and hopefully all remaining surveys.  Thankfully the hill’s summit is now free of forestry and as the Trimble gathered its summit data I sat with Aled and ate an apple, the only thing we were now worried about was running out of water, we had both brought extra bottles but their contents were being slowly sipped and there was still a long way to go.

Heading toward the summit of Pt. 526.8m (SN 745 611)

Gathering data at the summit of Pt. 526.8m (SN 745 611)

The next point to survey was the connecting bwlch to this 527m map heighted summit and interpolation placed it amongst or close to a small patch of remaining Scots pine forest, again the Trimble took us to this position and the allotted data gathered.

Exciting the trees a path of sorts through thick soft tussocks amongst patches of bog led us stumbling toward a fire break which would take us to the summit of Grug Crofftau.

Leaving the Scots pine wood

The forest ride leading toward the summit of Grug Crofftau

The high point of Grug Crofftau is close to a wide forest ride and about five rows of trees in to the forest, miraculously the Trimble attained its 0.1m accuracy level before data should be logged relatively quickly considering its position and gathered the all-important summit data without any form of objection.  We were now nearing the end of our surveying objectives but still had a long way to walk before reaching the awaiting car at Ystrad-fflur (Strata Florida).

Gathering data at the summit of Grug Crofftau

We excited the upper part of Grug Crofftau using another forest ride to take us down to the next bwlch which was positioned close to the waters of Llyn Crugnant, which is a wildly situated lake positioned in the grasslands of the Elenydd.  As the Trimble gathered data from the bwlch we both sat on tree stumps trying to recover from what was proving to be quite an ordeal of sun drenched and wild walking.

Llyn Crugnant

Only one survey remained and that was the summit of Llethr Brith, and thankfully a path led from the northern end of the bwlch that had just been surveyed to a forest ride that took us toward its high point which yet again was implanted firmly amongst the conifers.  It took a long time before the Trimble was activated and as we waited for ten minutes of data to be gathered swarms of midges and flies descended on us.

Gathering data at the summit of Llethr Brith

The summit of LLethr Brith was the last of 14 surveys taken during the day; I had visited seven summits and Aled eight, with Garn Gron being the extra one.  The land we had visited was uncompromising to say the least and the conditions severe with intense heat, and yet we had completed all that we had set off to do.  All that remained was the walk out, first down the continuation of the forest ride which brought us back to the forest track, I celebrated and knelt on the ground and kissed the gravel.

Reaching the forest track was like encountering an old friend.  Photo: Aled Williams

However, it was still a long walk out down the forest track where it intersected another which brought us down toward Hafod-newydd.  Walking down the green track toward this house the sun slowly ebbed behind hill ridges to our west as conifers rose skyward and took on a blackened hue accentuated by subline and gentle greens of fern and moss at their base.  Day was turning to night as dusk brought gentleness to this land.

The forest at dusk

Sunset

By the time we reached Hafod-newydd I was desperate to rest and started to wilt at an alarming rate, beyond the track continued downward, now out of the forestry toward a stream and a bridge that would if we had of continued, bring us to the narrow road taking us back to my car, but by this stage I was again almost done in, and when I saw a car on the track that was in the process of doing what looked like a seven point turn I gathered my last remaining strength and started shouting ‘hello’ and running toward the vehicle.  The driver kindly stopped his seven point turn and we tried to communicate, unfortunately he was almost deaf and only picked up certain words, thankfully those of 13 hours on the hill, exhausted, need water and please can we have a lift, seemed to do the trick and within a few minutes Aled was sitting in the back of the car with Henry the dog and I was sitting in the front with Denis, our saviour and driver.

Denis; our driver and saviour and his dog Henry

Denis had saved us another 40 minute walk back on the track and road, this I suspect would have been too much for me and I do not know how on earth I could have done it.  He dropped us off close to my car and we shook hands, what an absolutely lovely person he proved to be. 

I arrived home about midnight and was soon in bed feeling completely exhausted but also extremely happy at what we had accomplished during the day.  

Postscript:

Since the survey of these hills full LIDAR coverage is now available.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height and positional data that is now freely available for England and Wales.  Consequently the numerical details for these hills have been analysed using this technique, resulting in the LIDAR height and position for some of these hills being prioritised over that produced by the Trimble GeoXH 6000.

      

Survey Result:

Bryn y Crofftau

Summit Height:  447.3m (converted to OSGM15)

Summit Grid Reference:  SN 74807 63477

Bwlch Height:  411.5m (LIDAR)

Bwlch Grid Reference:  SN 74705 63091 (LIDAR)

Drop:  35.8m (Trimble summit and LIDAR bwlch)

Dominance:  8.01% (Trimble summit and LIDAR bwlch)

Carn Fflur

Summit Height:  501.3m (converted to OSGM15)

Summit Grid Reference:  SN 74626 62354

Bwlch Height:  480.6m (converted to OSGM15)

Bwlch Grid Reference:  SN 74694 62297

Drop:  20.7m (500m Sub-Twmpau status confirmed)

Dominance:  4.14%

Pt. 512.8m

Summit Height:  512.8m (converted to OSGM15)

Summit Grid Reference:  SN 74759 62033

Bwlch Height:  493.9m (converted to OSGM15)

Bwlch Grid Reference:  SN 74659 61518

Drop:  18.9m (Uchaf status confirmed)

Dominance:  3.69%

Pt. 516.9m

Summit Height:  516.9m (LIDAR)

Summit Grid Reference:  SN 75493 62086 (LIDAR)

Bwlch Height:  501.0m (LIDAR)

Bwlch Grid Reference:  SN 75576 61971 (LIDAR)

Drop:  15.8m (LIDAR) (Welsh Highland P15 reclassified to Welsh Highland Sub) (Welsh Highland Sub reclassified to Welsh Highland P15) 

Dominance:  3.06% (LIDAR)

Pt. 526.8m

Summit Height:  526.8m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 74595 61119 (Trimble GeoXH 6000)

Bwlch Height:  512.0m (LIDAR)

Bwlch Grid Reference:  SN 74980 61422 (LIDAR)

Drop:  14.8m (Trimble GeoXH 6000 summit and LIDAR bwlch) (Welsh Highland P15 addition) (Welsh Highland P15 reclassified to Welsh Highland Sub) (Pellennig addition) (Pellennig deletion) 

Dominance:  2.82% (Trimble GeoXH 6000 summit and LIDAR bwlch)

Remoteness:  2.700km (Pellennig addition)

Grug Crofftau (significant name change)

Summit Height:  533.3m (converted to OSGM15)

Summit Grid Reference:  SN 75031 61257

Bwlch Height:  504.3m (converted to OSGM15)

Bwlch Grid Reference:  SN 74415 61043

Drop:  29.0m

Dominance:  5.43%

Llethr Brith

Summit Height:  527.6m (converted to OSGM15)

Summit Grid Reference:  SN 75675 61410

Bwlch Height:  508.9m (converted to OSGM15)

Bwlch Grid Reference:  SN 75366 61428

Drop:  18.7m

Dominance:  3.55%

For further details please consult the Trimble Survey Spreadsheet