Monday 4 December 2017

Mapping Mountains – Trimble Surveys – Fforest Glud


03.10.17  Llandegle Rocks (SO 132 617), Bwlch y Cefn Bank (SO 123 608), Bwlch y Llwyn Bank (SO 118 599), Mynydd yr Heol (SO 107 601), Pawl Hir (SO 101 595), Bwlchau Bank (SO 117 587) and Y Graig (SO 133 590)

Bwlch y Cefn Bank (SO 123 608)

Many years ago I noticed that soon after visiting an area that I hadn’t been to for a while I was soon drawn back to near hills.  This has remained with me during the years I have hill walked.  It seems the atmosphere of places has an intrinsic pull upon the human psyche.  And having visited Castle Bank and adjacent hills only a month ago the delights of Radnorshire with its quiet seemingly undisturbed hills again pulled me toward them.

By 7.25am I was heading up steep grassed and brackened slopes toward the summit of Llandegle Rocks, away to the east the sun illuminated a high cloud now edged in delicate yellows, and quickly it rose casting a burst of white accentuated against a dark sombre land.

The imminent sunrise


A bust of white with the arrival of the sun

The forecast gave a good sunny morning with cloud building up in the afternoon, with dry but slightly windy conditions.  Thankfully I’d left my light autumnal fleece on as when I crested the northern ridge of Llandegle Rocks the early morning westerly wind chilled its way across the hill.

Looking across at Y Graig (SO 133 590) my last hill of the day

It was good to be on this hill again having only visited once before, I’d come prepared with a number of surveying objectives and the first was to take a data set from the high point beside the triangulation pillar atop one of the two tops of this hill, the second objective was to also get a data set from the other top, both are close in height with analysis of LIDAR data by Aled Williams favouring the non-trig pillared top as higher.

Gathering data beside the trig at one of two tops vying for highest summit atop Llandegle Rocks

As the Trimble beeped away gathering the allotted 300 datum points the sun sped morning colour on the hill and cast long shadows across the land.  Away to the south I looked out to the continuation of my walk and hills relatively distant that I hoped to visit and survey.

The Trimble confirmed Aled's analysis of LIDAR data and Llandegle Rocks now has a new summit

Once the two tops were Trimbled I headed south down to the connecting bwlch with Bwlch y Cefn Bank, a hill whose Pedwar status has only recently been taken from it.  Again, Aled’s analysis of LIDAR data led me to the critical bwlch which proved to be in a watery channel in an expanse of closely cropped grass where a herd of cows were frisking their way around the field, thankfully at a safe distance from where the Trimble was set up.

Gathering data at the critical bwlch of Bwlch y Cefn Bank

The summit of Bwlch y Cefn Bank lay ahead, all greened and dotted in white sheep.  Its summit is attractive and consists of rock; soon the Trimble was on the high point gathering another data set.  The wind whisked in from the west and gave the first few hours of the walk a bracing feel, autumn is here and although the sunned heat of summer can be pleasant on occasion I enjoy the time when extra layers of clothing are donned and a chill hits the hills.

Gathering data at the summit of Bwlch y Cefn Bank

This ridge consists of three good hills with Bwlch y Llwyn Bank being the furthest south and the lowest, all are worthwhile to visit.  Its bwlch was close to a fence and once the ten figure grid reference produced by LIDAR led me to it I set the Trimble up and waited for five minutes of data to be collected.

Bwlch y Llwyn Bank (SO 118 599)


Gathering data at the critical bwlch of Bwlch y Llwyn Bank

A narrowing path led from the bwlch up the hill to a large domed summit, I set the Trimble up on my rucksack and stood back as the next data set was taken.  To my north Bwlch y Cefn Bank and Llandegle Rocks were now partly shadowed as cloud layers built up, but their slopes were still predominantly bathed in sunshine, one contrasting the other with the former now a greened grazing land while the latter a dulled mountain green.

Gathering data at the summit of Bwlch y Llwyn Bank


Bwlch y Cefn Bank on left and Llandegle Rocks on the right

The next point to survey was the critical bwlch of Llandegle Rocks and the LIDAR grid reference led me to a slight dip beside a fence next to a puddled green track that headed down toward buildings named Bwlch-llwyn.  This hill was promoted to Subhump status in May 2014 due to the bwlch spot height on Ordnance Survey 1:50,000 Landranger maps which matched a levelled height on the series of Six-Inch maps, Aled had confirmed its addition via LIDAR data, and I now wanted to substantiate these data with a Trimble GeoXH 6000 survey.

Gathering data at the critical bwlch of Llandegle Rocks

My route now took a slight diversion from its natural course to take in two other hills, one currently listed as a Sub-Trichant and the other a potential 400m Sub-Pedwar.  The first is Mynydd yr Heol which was adorned with sheep contentedly grazing.

Mynydd yr Heol (SO 107 601), Wales' newest P30

A grassed track led up the hill whose summit was easy to identify and which is positioned above a small rock feature reminiscent of a quarry.  As data were gathered I looked out to the morning’s hills whose summits were now shadowed and toward the afternoon’s, still distant in distance and time.

Gathering data at the summit of Mynydd yr Heol


Pawl Hir from Mynydd yr Heol

The bwlch of Mynydd yr Heol was amongst a mass of reed grass which proved a squelchy affair; I assessed the lay of land from a number of directions before setting the Trimble up and contentedly waited for it to store its all-important data.

Gathering data at the critical bwlch of Mynydd yr Heol

The next hill; Pawr Hir, is given a 408m northerly spot height on Ordnance Survey maps as well as 407m southerly spot height on the enlarged map hosted on the Geograph website, I wanted to take data from each point.  My time on the summit area of Pawl Hir proved lengthy as I took four sets of data, each from a different position, the first on the easily identified northerly top and three from the southern.  During the wait on the southern top a couple passed and stopped to talk, they were on the good track close to the high point of this hill that heads west toward two lakes which are relatively recent additions to the landscape as they don’t appear on old maps.

Gathering data at the first of four positions surveyed for the summit of Pawl Hir

Once these four summit data were stored I headed down to the hill’s connecting bwlch hoping for an easy survey, it proved not to be as the whole area of the bwlch consisted of standing water that oozed the smell of methane when I tried to venture in to it.  I definitely needed to be wearing wellies to attempt to get in to this, but as the water was standing I judged its height to be level and set the Trimble up on my rucksack as far in to the watery depths that I could safely go.  After stamping down a clump of reed grass to at least give my rucksack a semblance of dry protection from getting a soggy bottom I waited until the Trimble had gathered its allotted five minutes of data.

Gathering data at the first of two positions surveyed for the bwlch of Pawl Hir

Before leaving the bwlch I took another data set further east with the Trimble on top of a fence post, there was less bog here and I wanted to compare the valley to valley data.

Retracing my steps back over the southern summit of Pawl Hir I re-joined the good green track and followed it down to the minor road close to where I’d previously taken the data set from for the bwlch position of Llandegle Rocks.  The minor road headed south-eastward toward the critical bwlch of my next hill.

Approaching the bwlch of Bwlchau Bank with the hill in the background

Ordnance Survey maps give a 317m spot height on this road, I judged the critical point to be north-eastward from the low point of the road which had been built up to avoid the worst of any marshy land.  Whilst collecting data a farm vehicle drew up and I explained to Keith Williams what I was doing and never one to pass an opportunity for place-name enquiries with a local farmer, I asked him the names of the local hills, he told me that the hill behind him (to the south-east and which was my next summit) was known as Bwlchau Bank and that the hill off in the distance that has a wind turbine and a small mast on top was known as The Graig.

Gathering data at the critical bwlch of Bwlchau Bank

After Keith drove off I packed the Trimble away having collected over ten minutes of bwlch data and followed the road to a gate which gave access to a wood and field leading to the summit of Bwlchau Bank.  The summit has a fence over it and a 348m map spot height at or close to the fence, the hill’s high point is a grassed bank which consists of an old stone wall with the fence perched on top of it, I set the Trimble up at what I judged to be the base of the grassed wall where I deemed the high point of the natural hill to be placed.

Gathering data at the summit of Bwlchau Bank

Once data were stored I headed north-eastward through a mass of nettles and steeply down grassed slopes to the corner of a wood, I walked through the wood for a short distance before exiting in to a field which led down to a right of way following a small stream valley next to Keith’s farm of Hendy.  I wanted to avoid the Graig farm as Keith had informed me that they are reluctant to give permission to visit their hill, and this was the last summit I wanted to survey.

The route up was initially on the track which is a right of way, I then followed another track to a field and contoured over grassed and quiet slopes to another field and a gate which gave access to the track that heads up the hill from the farm.  I was always aware that a vehicle may come zooming up the track so I made as quick progress as I could and followed a track to a large barn and the upper field to the top of the hill.

All was quiet on the summit of Y Graig whilst the Trimble beeped away gathering its 18th and last data set of the day, the wind still whisked in but I was happy that I’d completed all I wanted to do, saying that there was still the critical bwlch of Y Graig remaining to survey, this was in or beside the edge of a conifer plantation whose perimeter looked as if it was decidedly boggy, an alternate route down looked much easier and I chose the latter and headed down the hill toward Pye Corner; a house at the end of a minor paved road.

Gathering data at the summit of Y Graig

I soon passed the expanse of Llanwefr Pool, a forgotten place amongst many such places in the Radnorshire hills.  Its perimeter was festooned in greened reed and no doubt an extremely boggy place to venture.

Llanwefr Pool with Llandegle Rocks in the background

By the time I reached Pye Corner I felt weary, the trudge up the narrow paved road only added to my dilapidated state, I now had about a mile to walk on the A 44 road to my awaiting car, after a steady ten minutes or so of slow progress my smiling face and thumb did the trick and a car stopped, picked me up and whizzed me off the remainder of distance to my car.    


  
Survey Result:



Llandegle Rocks

Summit Height:  436.3m (converted to OSGM15)

Summit Grid Reference:  SO 13202 61752 (summit relocation confirmed)

Bwlch Height:  345.5m (converted to OSGM15)

Bwlch Grid Reference:  SO 11361 59616


Dominance:  20.82%





Bwlch y Cefn Bank


Summit Grid Reference:  SO 12369 60880

Bwlch Height:  347.2m (converted to OSGM15)

Bwlch Grid Reference:  SO 12752 60893

Drop:  52.7m

Dominance:  13.19%





Bwlch y Llwyn Bank

Summit Height:  396.7m (converted to OSGM15)

Summit Grid Reference:  SO 11895 59978

Bwlch Height:  352.7m (converted to OSGM15)

Bwlch Grid Reference:  SO 12111 60509

Drop:  44.0m

Dominance:  11.09%





Mynydd yr Heol

Summit Height:  386.8m (converted to OSGM15) (significant height revision)

Summit Grid Reference:  SO 10793 60177

Bwlch Height:  355.6m (converted to OSGM15)

Bwlch Grid Reference:  SO 10701 59917


Dominance:  8.07%





Pawl Hir

Summit Height:  405.8m (converted to OSGM15) (significant height revision)

Summit Grid Reference:  SO 10108 59510 (summit relocation confirmed)

Bwlch Height:  388.9m (converted to OSGM15)

Bwlch Grid Reference:  SO 10082 59269

Drop:  16.9m (non 400m Sub-Pedwar status confirmed)

Dominance:  4.17%






Summit Height:  348.3m (converted to OSGM15)

Summit Grid Reference:  SO 11770 58788

Bwlch Height:  316.6m (converted to OSGM15)

Bwlch Grid Reference:  SO 11399 59331


Dominance:  9.09%






Summit Height:  371.5m (converted to OSGM15)

Summit Grid Reference:  SO 13372 59020

Drop:  c 60m

Dominance:  16.15%




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