Monday, 8 August 2016

Mapping Mountains – Trimble Surveys – Pumlumon


18.07.16  Y Drum (SN 828 845), Esgair y Maesnant (SN 832 862), Tor Du (SN 842 856), Y Foel (SN 838 842) and Tir Gwyn (SN 848 841)

Y Foel (SN 838 842)

I’d wanted to re-visit these hills for a number of years and accurately survey the summits and bylchau of Esgair y Maesnant and Tor Du, the latter was only classified as a Dewey after a rudimentary survey that I had conducted in July 2000, whilst the former is currently listed as having 29m of drop.

Each hill and their adjacent neighbours can be combined in a good circuit from the south following the infant Afon Gwy (River Wye) as it meanders up to its source amongst the high Pumlumon.

The access to this valley and the hills above follows a number of vehicle tracks set in place partly for the local farmer, but mainly for rallying.  As I left my car and walked over the road to the farm yard of what is commonly known as Sweet Lambs I met four or five farmers happily lazing in the early morning sun vapouring on their E-cigarettes, this I thought rather unusual, where once a cigarette’s smoke would linger amongst the early morning scent of summer, it had been replaced by an electronic cigarette, somehow the whole scene looked a little out of place.  I stopped and chatted for ten minutes or so and asked about the names of the local hills, many were confirmed as what the map gives with one or two locally known names also given.  As I thanked them for their time I turned to head up the track as they all made a move to their various vehicles.  Passing a pick-up truck one of the men; Huw Meyrick, started talking about the hills and their names and I stopped and the conversation continued, five minutes later I was sitting in his pick-up truck with two sheep dogs in the back as Huw drove up the track and dropped me off high on the hill at the bwlch that connects Y Drum with Esgair y Maesnant.  This had probably saved me 90 minutes of walking and as the forecast for the day predicted hot weather with temperatures in the mid 20’s I was thankful for the lift.  We stood outside the pick-up for a while and Huw pointed out each hill and gave its name, encounters like this are to be welcomed and are proving more common on my hill walks.

Huw Meyrick and accompanying dogs

As Huw drove up the continuation of the track I shouldered my rucksack and walked up the opposing track to the summit of Y Drum, a 462m map heighted Pedwar.  By now it was pleasantly warm with only a slight breath of breeze, the land looked inviting and green with early morning low cloud over the high Pumlumon ridge being quickly burnt off. 

After gathering five minutes of data from the summit of Y Drum I retraced my steps back down the track to the connecting bwlch and set the Trimble up on the track where the valley to valley traverse met the hill to hill traverse, five minutes later the equipment was packed away and I continued on the track contouring around the south-western slopes of Bryn Daith; a minor 498m map heighted lump. 

Gathering data at the summit of Y Drum

Gathering data at the critical bwlch of Y Drum

Y Drum (SN 828 845) in centre of photograph

The next point to survey was the critical bwlch of Esgair y Maesnant, which is listed as a marginal 500m Sub-Twmpau.  The area of the bwlch looks out toward the south-eastern slopes of Pumlumon Arwystli and across to the north to the first conifers of the Hafren Forest.  It isn’t an easy bwlch to judge where the critical point lies as the ground undulates and comprises tussock grass and heather.  I took data from three points all on the hill to hill traverse, and took two data sets from the point I visually judged to be that of the critical bwlch.

Gathering data from one of four data sets taken on the area of the bwlch of Esgair y Maesnant with part of the Hafren Forest in the background

All this takes time and as I left the bwlch to walk up to the summit of Esgair y Maesnant the sun beat down as it would do for the remainder of the day.  I sometimes wonder how on earth I surveyed some of the hills with my old wooden staff as many are on unremitting ground where tussocks predominate, and Esgair y Maesnant is such a hill.  When I surveyed this hill I never ventured down to its connecting bwlch with Tor Du and just took a reading with a spirit level aligned with the high point of Esgair y Maesnant, this gave me an approximate 5ft difference in height with Tor Du being the higher.  Having the Trimble gives me the opportunity to re-visit such hills and give each an accurate height and drop.

I took three data sets from the summit area of Esgair y Maesnant, two close to where its 504m summit spot height appears on Ordnance Survey maps, and the third from the high point of its easterly 500m ring contour which is given a 502m spot height on the Ordnance Survey enlarged map on the Geograph website.  After this I walked down into long grassed mayhem.

Gathering data from the summit of Esgair y Maesnant

The continuation of my planned route now took me towards the bwlch that I didn’t visit when I surveyed these hills with my old rudimentary staff.  The underfoot conditions proved problematic as the grasslands were vast and luxuriant, beautiful in their own right with greens piecing the view, but they proved a leg sapping nightmare to walk through!

Long green luxuriant tussock grass, beautiful to look at but a major obstacle to walk through

The bwlch proved relatively easy to find where its critical point lay, which was a surprise considering the assortment of roughness hereabouts.  I took two data sets from the same point and having packed the equipment away I stumbled through the thick tussock grass down to the joys of one of the tracks that meander around these hills.  As I reached the track I walked a few metres uphill and had to stop and regain my breath, the afternoon was proving decidedly warm and I was suffering.

Gathering data at the critical bwlch of Tor Du

The track soon split with each branch encircling the summit of Tor Du; I headed on the left hand branch and slowly plodded up to the summit.  It really was overly warm to be out on the hills, some people enjoy the real warmth of summer and luxuriate in its charms on the hill, I’ve found that it makes me wilt and have learnt to accustom my pace to its incessant debilitation.  I took another two data sets from the same summit position atop Tor Du and in the process tried to recover and stop sweating.

Gathering data from the summit of Tor Du

Y Foel from the summit of Tor Du

Tracks now led all the way to the summit of my next hill of the day; Y Foel.  On the way I took a diversion to survey its bwlch which was positioned to the east of the track and adjacent to a small conifer plantation.  Its critical point was at or very near to the boundary fence separating the trees in a conifer plantation from the grassland of the hillsides.  A fence post above where I judged the critical bwlch to lie proved a convenient place to position the Trimble, and although the post was only narrow the Trimble just had enough room to balance on top, I quickly measured a 1.14m offset between the equipment’s internal antenna and the ground at the base of the fence post and once the 0.1m accuracy level was attained, I pressed ‘Log’ and scampered away for the next five minutes of data collection.

Gathering data at the critical bwlch of Y Foel

After this bwlch survey I slowly plodded back to the track and on my way up it toward the summit of Y Foel I realised that the sun was taking its toll as my arms and legs were burnt and my body was flagging, I dread to think how I would have felt if I hadn’t got the lift earlier in the day.  The summit of Y Foel once had a large mast on it which is now recumbent and rusting; I took another two data sets, both to the north of where its base has now been upended.

An ingenious way for a farm vehicle to bi-pass a gate and for livestock to remain in their enclosure

Tor Du from the track to Y Foel

Gathering data from the summit area of Y Foel

I only had one hill left to survey; Tir Gwyn, and although the continuation of the track headed down to near its bwlch I decided rather stupidly to head straight for it and got bogged down and floundered in huge tussocks, to the point that I gave up and aimed for the track which was now on my right, when I arrived on it I plodded down to a near gate and rested.

I’d only visited Tir Gwyn once before and had a memory that a vehicle track on the moor led to its summit, but it was the bwlch I now wanted to visit and thankfully a vehicle track led through the grass and heather towards where its critical point lay.  I took another three data sets from the area of this hill’s bwlch and whilst the Trimble gathered its individual five minute data sets I sat in the heather and recovered.  Although close to the track, which itself is relatively close to the valley and the A 44 as it marches westward from Llangurig toward Aberystwyth, the surrounds of the bwlch were beautiful and wild, few people must visit as there doesn’t seem a reason why one would, but its quietness and luxuriant undergrowth portrayed peacefulness.

Gathering data at the critical bwlch of Tir Gwyn

Once back on the vehicle track I followed it to high on the hill and diverted as it run out and I then headed straight toward the summit, this was the last of 20 data sets taken during the day, and once five minutes of data were collected I headed back down to the track and pottered down toward the valley below.  This proved a hot grind as the day was now very warm without any form of breeze, and even walking down hill I had to take rests as my body had succumbed to the heat.  Once back at the car I sat and rested in the sunshine and luxuriated in the joy and comfort of movement that had ceased.

Gathering data from the summit of Tir Gwyn, the 20th and last data set of the day

  
Survey Result:


Y Drum

Summit Height:  460.9m (converted to OSGM15)

Summit Grid Reference:  SN 82821 84594

Bwlch Height:  416.7m (converted to OSGM15)

Bwlch Grid Reference:  SN 82934 84978

Drop:  44.2m

Dominance:  9.59% 

 

Esgair y Maesnant

Summit Height:  503.6m (converted to OSGM15) (500m Sub-Twmpau status confirmed)

Summit Grid Reference:  SN 83220 86275

Bwlch Height:  476.2m (converted to OSGM15)

Bwlch Grid Reference:  SN 82792 86427

Drop:  27.3m (500m Sub-Twmpau status confirmed)

Dominance:  5.42%


  

Summit Height:  505.6m (converted to OSGM15)

Summit Grid Reference:  SN 84268 85679

Bwlch Height:  472.4m (converted to OSGM15)

Bwlch Grid Reference:  SN 83846 85958

Drop:  33.2m (Dewey and 500m Twmpau status confirmed)

Dominance:  6.56%



Y Foel

Summit Height:  545.8m (converted to OSGM15)

Summit Grid Reference:  SN 83826 84206

Bwlch Height:  468.2m (converted to OSGM15)

Bwlch Grid Reference:  SN 83788 85410

Drop:  77.5m

Dominance:  14.21%












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