Wednesday 16 October 2019

Mapping Mountains – Trimble Surveys – Fforest Fawr


27.07.19  Carreg Cadno (SN 874 161), Pt. 529.6m (SN 878 160), Pt. 524.3m (SN 881 163) and Twyn y Ffald (SN 852 160)  

Carreg Cadno (SN 874 161)

With Mark having driven to Welshpool, I continued to Caersŵs where Aled was parked and ready for the continuation south to the southern part of Fforest Fawr, where a number of limestone hills awaited for the three of us, and also the higher hills to the north for Aled and Mark.

We set off walking in warm late morning sunshine from the large parking area at Penwyllt.  I’d visited this area once before in July 2002 when along with Lisa we combined the higher Fan Gyhirych and Fan Fraith with the lower Carreg Cadno and finished the day with a welcome pub meal in Llyswen.

A public footpath strode confidently toward the limestone summits that looked out upon this seldom visited area of Fforest Fawr.  The path continued over a disused tramline, with the northerly section of this later being used as part of my descent route.  Soon afterward the path joined a fence and continued upward with only the last few minutes across summer grasses and limestone rock leading us away from the path and toward the summit of Carreg Cadno.

Heading for the hills

This hill is crowned by a large rock which requires a quick scramble to get to its top, and once there I set the equipment up with the Trimble’s internal antenna aligned with the high point and lay below it as it beeped away gathering its datum points.  Once the allotted data were gathered and stored I switched it off, took a few photos and joined Mark and Aled who were sitting in the pleasing sunshine having a bite to eat.

Mark at the summit of Carreg Cadno

As I wanted to survey the summit and connecting bwlch of four hills, Aled had suggested that he and Mark could leave me to my surveying activities whilst they continued northward toward Fan Gyhirych, with Penwaundwr (SN 907 228) being our rendezvous spot in three to four hours’ time.  Therefore as Aled headed east toward the next limestone summit I followed and watched him gain height toward its top, whilst I headed in to thick grassland to the hill’s connecting bwlch.  As data were gathered Mark passed heading toward Aled, and as the equipment was closed down having gathered the allotted data we waved at one another and that would be the last I saw of them for a number of hours.

Pt. 529.6m (SN 878 160)

The compact area taking in Carreg Cadno also takes in two lower limestone summits, all had been LIDARed by Aled and I now wanted to repeat the process with the Trimble.  The land consists of thick grassland, patches of heather with rubbled limestone, at a contrast to the higher hills immediately to the north.

Gathering data at the bwlch of Pt. 529.6m

I was soon on top of the second summit and had the Trimble set-up and gathering data within a few minutes.  During this a dark mass of threatening cloud had built up to the north and as data were gathered this became darker and loomed over the higher hills ready to unload what looked like a deluge.

Gathering data at the summit of Pt. 529.6m

The next point to survey was the connecting bwlch to a 524m map heighted summit that has an old cairn on top.  The bwlch was a few metres north from a green track that passes over the hills, and whilst the Trimble squatted in the thick grassland atop my rucksack I spotted a couple heading my way on the green track.  They reached me just as the Trimble had gathered its allotted five minutes of data, they stopped and we chatted for a few minutes before I scampered off to switch the equipment off and take a number of photos as the dark mass of cloud bore down on the hills.

Pt. 524.3m (SN 881 163)

Gathering data at the bwlch of Pt. 524.3m

As the Trimble gathered data from the third summit the first raindrops scattered in the breeze.  This felt refreshing after the warmth of the ascent and with a warm breeze skimming across the land and with the grassland swaying in tune it felt good to be out. However, the rain soon increased in strength and once the allotted data were gathered and stored and the equipment switched off and packed away, I put my Goretex on and headed north toward a gravelled track which in time would lead me down to the disused tramway and railway.  But before that I had one more survey to conduct which lay further north.

Gathering data at the summit of Pt. 524.3m

The connecting bwlch of Carreg Cadno sits in thick grassland with a few small puddled bogs squat-like waiting for any unsuspecting walkers who may for whatever reason pass this way, I doubt this often happens as there is no reason why such a place would be visited unless wanting to survey it, which I did.

Gathering data at the bwlch of Carreg Cadno

During the bwlch survey the rain lessened and once back on the track and height regained I stopped to take my Goretex off and enjoyed the rest of the walk unencumbered in the afternoon warmth.  The gravel track led down to a series of grassed switchbacks which give access down to the remains of what is now a disused railway line.  A few minutes to the south lay the connecting bwlch for the final hill of the day; Twyn y Ffald, which is now listed as a Sub-Trichant due to LIDAR analysis conducted by Aled.

Twyn y Ffald (SN 852 160)

The connecting bwlch was positioned close to a barb wired fence amongst wild flowers and swaying grasses.  Whilst data were gathered I stood contemplative in the afternoon warmth and looked out past the survey equipment to the rising bulk of Fan Gyrhirych, which loomed darkly silhouetted in the distance.

Gathering data at the bwlch of Twyn y Ffald

All that remained was to visit and survey the summit of Twyn y Ffald and the continuation of the path beside the old disused railway line brought me to its broad and grassed ridge which bi-passed the depths of the near quarry. 

The summit was a delight, with wind-blown wild flowers madly swaying against the two small fangs of rock which constitutes its high point.  Once my rucksack was wedged between the two rocks and the Trimble balanced on top of it and its internal antenna fixed on top of the highest bit of rock, I waited for the allotted data to be stored and luxuriated myself with the view and watched the movement of grass and flowers as the breeze blew.

Gathering data at the summit of Twyn y Ffald

All that remained was the descent to the quarry floor and a walk back to my car and the drive north to pick Aled and Mark up, who when I arrived, were sitting beside the road in the late afternoon sunshine having been waiting for about ten minutes; not bad timing!



Survey Result:



Carreg Cadno 
 
Summit Height:  538.4m (converted to OSGM15)

Summit Grid Reference:  SN 87423 16132

Bwlch Height:  502.9m (converted to OSGM15)

Bwlch Grid Reference:  SN 88466 17006

Drop:  35.5m

Dominance:  6.60%




Pt. 529.6m 
 
Summit Height:  529.6m (converted to OSGM15)

Summit Grid Reference:  SN 87887 16087

Bwlch Height:  510.4m (converted to OSGM15)

Bwlch Grid Reference:  SN 87705 16096

Drop:  19.1m

Dominance:  3.61%




Pt. 524.3m
  
Summit Height:  524.3m (converted to OSGM15)

Summit Grid Reference:  SN 88113 16370

Bwlch Height:  509.2m (converted to OSGM15)

Bwlch Grid Reference:  SN 87908 16298


Dominance:  2.87%




Twyn y Ffald 
 
Summit Height:  369.2m (converted to OSGM15)

Summit Grid Reference:  SN 85226 16033

Bwlch Height:  342.5m (converted to OSGM15)

Bwlch Grid Reference:  SN 85540 16185

Drop:  26.7m (Sub-Trichant addition)

Dominance:  7.23%








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