Saturday, 27 February 2016

Mapping Mountains – Trimble Surveys – Pegwn Mawr


18.02.16  Tyfaenor Park (SO 070 715), Cwm Cringlyn Bank (SO 072 725), 

Cwm Cynydd Bank (SO 061 726), Cwm Cynydd Bank (SO 053 724, not 

Trimbled) and Little Park (SO 051 717, not Trimbled)  

Cwm Cynydd Bank (SO 061 726)

The delights of forested tops are an acquired taste, these delights I am still unsure of, as on occasion when immersed in a conifer plantation I am prone to wonder why I am doing what I am doing, this is particularly prevalent when brambles are present, and these when combined with wind felled trees add a little gruesomeness to proceedings.  The latter part of today’s walk combined all of the above and proved to be a fine example of hell on a hill.

I set off from Abaty Cwm-hir (Abbey Cwmhir) having parked in front of the resplendent looking St Mary’s Church, immediately behind the church the framed and rounded forested hill of Little Park rose to the blue sky above.  I hoped that this hill would be my last of the day, but this was dependent upon a number of forest tracks being accessible.

Little Park with St Mary's Church in the foreground

Heading east on a minor paved road and then a narrow lane toward Llwyn-onn, the morning’s mist ebbed its last as sun’s warmth diligently worked on the frost laden land.  I left the narrow lane and followed a track toward Brynmoel and chatted with a couple walking their dogs before taking to the fields beyond.

A track led down from the fields back to the minor road before I branched up a lane to the old farm house of Tŷ-faenor (Dyfaenor), which no doubt gives its name toward the first hill on my route; Tyfaenor Park.  As I walked up the steep track beyond the farm, snowdrops sparkled out of their rooted den.  These beautiful plants are one of the first signs that warmth and the heralding of seasonal change is upon us, but today winter’s chill was still in the air, and as I made my way up through a series of foot stiles and gates toward the summit of Tyfaenor Park a slight breeze blew the sun’s warmth leaving gloved hands to operate the Trimble.

The late winter Snowdrop

The summit of Tyfaenor Park is easily identifiable and soon the Trimble was beeping away collecting its allotted 300 points which is equivalent to five minutes of data.  During this time I took a series of photographs, looking across the Clywedog Brook to the elongated shape of Llywy, a 466m map heighted Pedwar, and one which I have yet to visit.  To my west the forested summit of Great Park seemed relatively easily attainable from its reclaimed green and high pastured adjacent land.  The view to my north-west showed the ravages of conifer plantation as the summit of Cwm Cynydd Bank was completely swamped by trees.  Lastly, the continuation of land to my immediate north led to the next summit on my walk; Cwm Cringlyn Bank, thankfully free of conifers and framed by a number of sheep happily grazing in the morning’s sunshine.

Llywy (SO 054 704)

Great Park (SO 059 717)

Gathering data at the summit of Tyfaenor Park

Cwm Cringlyn Bank (SO 072 725)

Once the Trimble was packed away I quickly walked down to the connecting bwlch, assessed the lay of land, chose the spot for the critical bwlch and positioned the Trimble on top of my rucksack to give it elevation above its immediate surrounds.  As it gathered data I watched a number of sheep heading down the northern slopes of Tyfaenor Park as the sun illuminated their white fleeces from behind.

Gathering data at the critical bwlch of Tyfaenor Park

By the time I’d walked up to the summit of Cwm Cringlyn Bank the blue sky to the west had been overtaken by a mass of grey murk that slowly crept its way across some of the higher summits.  After the Trimble had done its stuff I quickly packed it away and scampered off following a path north-west toward my forest adventure.  By the time I entered the forest the first drops of snow were falling, adding an ethereal atmosphere to my suddenly darkened habitat.  I considered attempting to gather data just inside the forest at the bwlch of Cwm Cringlyn Bank but quickly abandoned the idea and set off following a muddied path to a near forest track.

Gathering data at the summit of Cwm Cringlyn Bank as the snow showers mass

By the time I reached the forest track the noise of vehicles became evident; I marched on and hoped that I wouldn’t encounter any forest workers.  Close to where the path leaves one of the forest tracks and heads confidently toward the summit of my next hill; Cwm Cynydd Bank, I started to come across a number of cars and trucks parked on the forest track.  The entrance to my summit path was cordoned off with tape signifying that workings had, or were taking place somewhere in the vicinity of the summit, I quietly walked around the tape and up the muddied path as a large forest truck stacked full of felled trees rumbled its way across the track I had just left.  Seemingly my presence had remained undiscovered and I continued walking up the path as the noise of the forest workings progressively became distant.

The path leading toward the summit of Cwm Cynydd Bank (SO 061 726)

This part of the hill had recently been worked as a number of stacked tree trunks lay across the hillside and the path was a muddy affair with vehicle tracks evident.  The path conveniently headed straight up the eastern broad ridge of Cwm Cynydd Bank and just bi-passes the hill’s high point, which is a few metres north of the path and within mature plantation.  The only spot height appearing for this hill on any current publicly available Ordnance Survey map is 450m which appears on the 1:50,000 Landranger map, so I hoped to gather at least some data to compare the Trimble height with that of this spot height.

My patient wait at the summit of Cwn Cynydd Bank was a long affair, I had set the Trimble up on my rucksack which itself was sitting atop a tree stump, with the overall measurement offset between the position of the internal antenna within the Trimble and the base of the tree stump measured as 0.73m.  I waited, and waited, and slowly became colder and colder, I paced to and fro trying to retain some body heat and took to standing in a patch of sunlight as it broke through the canopy of trees and bathed warmth in to the forestry.  Eventually I pressed ‘Log’ and gathered a few minutes of data.

Gathering data at the summit of Cwm Cynydd Bank (SO 061 726)

It had taken a long time to come away with my prized possession of summit data and I did not want to repeat this lengthy wait again, so when I walked down to the connecting bwlch with the adjacent 444m map heighted hill at SO 052 725 I decided to set the Trimble up at this bwlch and waited five minutes or so, but when the accuracy level was still too high to log data, I closed it off, packed it away and continued following the forest track and then path to what I thought to be the summit.  The summit of this hill was subsequently analysed with LIDAR data by Aled Williams producing a height of 451.4m at SO 05342 72437 (please refer to the following Hill Reclassifications post for full details).  I then had an option to double back and follow the main forest track toward the bwlch connecting with my last hill of the day; Little Park, or continue down on a path toward the area of the self-same bwlch.  I chose the latter and popped back out in to sunshine where tracks and paths meet to the north of the 401m map heighted summit of Y Glog.

The next part of the walk was where the real fun started, as I walked up the track to my east and left it where the connecting bwlch to Little Park lay to my south.  This bwlch is now positioned in mature forestry which proved easy to walk through, but ahead were signs of wind-blown trees, fallen at a variety of angles and all prostrate with their slender tops facing eastward.  I tried to keep to their western side and bi-passed their uprooted ends thinking that the eastern side of the ridge would be similar to an assault course.  As the upper part of the hill rose in front I decided that I would have to go for it, a big mistake, as tackling the uprooted and fallen trees became a nightmare of tangled undergrowth which quickly got out of hand with the unwelcome addition of a copious amount of brambles, my progress became sloth like as I tried to head straight up only to find that this was impossible, therefore I tried following the length of each fallen tree and forlornly attempted to then zig zag between them, the whole upper part of the hill was a stack of bramble, wet rotted tree branches, moss, fallen conifers and mayhem.  However, bit by bit I made progress and neared a high point which was within a few metres of where the spot height for this hill appears on the ground, but even getting to it was a task as I circumnavigated it to try and find a way in, brambles extended at all angles and became a major problem, I eventually barged my way through and stood on the top,  unfortunately Trimbling it proved an impossibility and I wish I’d taken a photo, but I didn’t, as I wanted to push farther in to the assault course and see if any other high ground existed to my south, I tried this for a few minutes and found that my perseverance was ebbing, before I stopped I looked to my south and peered through a canopy of fallen trees and brambles and could see nothing higher, and so decided that I must now try and get back to the safety of the forest track.  My backward route was much easier as I decided to loose height to my west and get below the wind-blown trees and then bi-pass their delights on the western side of the hill.  Before leaving the brambles I took a couple of photos looking back toward the summit, neither do the upper part of this hill justice, as its whole upper section seems to be made out of fallen trees and brambles.  I wish others going this way good luck, and if approaching from the forest track to this hill’s north I would highly recommend keeping relatively low on the western side of the summit and then when aligned with it, heading straight up toward it, and not attempting an ascent direct from its connecting bwlch, this is full of silliness and stupidity, and yet after the event I was glad that I had done it as some form of unusual pleasure had been gained!

The joys of Little Park

Looking back toward the summit of Little Park

It took me 45 minutes to get from the relative safety and comfort of the forest track to the hell of the summit and back again.  Once on the forest track I dusted myself down, prized out a large hanging bramble which had attached itself to my hair, and continued down toward where a path headed off downhill on the eastern side of Y Glog.

As I followed this path down the forested top of Little Park rose in a sun drenched and rather beautiful way, looking a teense innocent and attractive, but also standing bold as brass, unwavering in its simplicity, as nowadays it is a hill made out of trees, with its high point being a summit made out of fallen trees.

The upper southern section of Little Park

The south-eastern aspect of Little Park

In time the path led down to where my car was parked, as I arrived a man appeared walking up the road with a rucksack on, we chatted for a number of minutes and showed one another our routes on a printed off segment of a map he had.  He’d had a battle with a bog and we both smiled when I told him I’d had a battle with some trees.

I left the village of Abaty Cwm-hir (Abbey Cwmhir) and drove north to Bwlch y Sarnau and then east to where the critical bwlch for Cwm Cynydd Bank (summit at SO 061 726) is positioned.  As the Trimble gathered its last data set of the day positioned on top of my rucksack beside a minor road, I watched sheep inquisitively watching me from an adjacent field.  Once five minutes of data were gathered I packed the Trimble away and headed toward the car and home happy in the knowledge that another four P30s had been bagged, with three of them being Pedwarau to add to my ever increasing total. 

Gathering data at the critical bwlch of Cwm Cynydd Bank (summit at SO 061 726) 

  
Survey Result:



Summit Height:  383.1m (converted to OSGM15)

Summit Grid Reference:  SO 07078 71589

Bwlch Height:  350.4m (converted to OSGM15)

Bwlch Grid Reference:  SO 06990 71894

Drop:  32.7m (Trichant status confirmed)

Dominance:  8.54%



Cwm Cringlyn Bank

Summit Height:  423.2m (converted to OSGM15)

Summit Grid Reference:  SO 07215 72545

Drop:  55m

Dominance:  13.00%



Cwm Cynydd Bank (significant name change)

Summit Height:  454.9 (converted to OSGM15) (significant height revision)

Summit Grid Reference:  SO 06116 72668

Bwlch Height:  370.9m (converted to OSGM15)

Bwlch Grid Reference:  SO 04667 74183

Drop:  83.9m

Dominance:  18.45%



Cwm Cynydd Bank

Summit Height:  451.4m (LIDAR data)

Summit Grid Reference:  SO 05342 72437

Bwlch Height:  416.4m (LIDAR data)

Bwlch Grid Reference:  SO 05788 72576

Drop:  35.0m (LIDAR data) (400m Sub-Pedwar reclassified to Pedwar)

Dominance:  7.75%



For further details please consult the Trimble survey spreadsheet click {here}



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