Mapping Mountains – Trimble Surveys – Cymoedd Morgannwg

23.07.16  Pt. 523m (SS 928 951)    

Pt. 523m (SS 928 951)

This hill is positioned beside the A 4107 as it makes its way from the junction with the A 4061 above Hirwaun, westward toward the confines of Abergwynfi and Cwm Afan.  Because of this it is no more than a few minutes stroll to its grassed top.  It is rather forgotten, as many hills are that have higher and more prominent neighbours, but according to a basic levelling survey conducted in August 2005 it is close to meeting the requirements for Uchaf qualification, these are the Welsh hills at or over 500m in height that have a minimum of 15m of drop, and is a list that Aled and I plan on publishing in the future.

Toward the end of the time that I was wandering the Welsh hills surveying for drop with my rudimentary staff I was also making place-name enquiries, and this hill has a locally known name, however the point (Pt. 523m) notation is currently being used for this hill as its locally known name will be given when the list known tentatively as Yr Uchafion is published.

The bwlch connecting this hill to its higher neighbour is positioned north-westward of its summit and the A 4107 runs across it in roughly a hill to hill direction.  The road is elevated above its surrounding land with prominent ditches below and earthen embankments on either side.  When I first surveyed this hill I noted the roads elevation and the ditches below it and measured from the low point of the road to the summit of the hill.  Eleven years later and I now wanted to take a series of readings from the area of the bwlch.

The elevated road passing over the area of the bwlch

I parked just off the road where a motorcycle track veers up to the hill and proceeded to walk the short distance down the road and on to the natural ground to its south.  Immediately I dropped down in to the ditch and then walked up the other side on to what can be viewed as a part of the remaining natural ground of the hill.  I took one data set from where I judged the low point of this ground on the hill to hill traverse to be situated and then headed back to the road.

The Trimble set-up position on the south side of the road

Above the road on either side of it is also an embankment, I stood on top on this on its southern side and assessed the road for its low point as I wanted to take a data set from this point to compare its elevation to the remaining natural ground on its northern and southern sides.  The assessment of the roads low point was made easier by the placement of two manhole covers directly opposite one another, these are good indicators where water run off goes and are usually placed at the low point of a road.

The next data set was taken at what I judged to be the low point of the hill to hill traverse on the ground to the north of the road, it is this position that I think to be the point where the natural critical bwlch still exists as cotton grass and a small bog laden grassy channel crept upward to the luxuriant greened summer grasslands of the bwlch.  Once another five minute data set had been gathered I packed the equipment away and headed up to the hill’s summit.

The Trimble set-up position on the north side of the road

The summit area has two tops with the further westerly one the higher, I placed the Trimble on top of my rucksack to give it elevation above the long grass, measured a 0.42m offset between the equipment’s internal antenna and the ground at the base of the rucksack and set it to collect data.  All that remained was to take a data set from the low point of the road.

Gathering data at the summit of Pt. 523m

As I headed down the hill to where my car was parked a westerly cloud bank edged ever eastward, this heralded rain which was predicted in this part of the country by late afternoon.  I moved my car down the road and positioned it next to the manhole cover signifying where I judged the low point of the road to be situated and positioned the Trimble on top of the car’s roof, measured a 1.44m offset and set the equipment to gather the last of the day’s five minute data sets.

The afternoon's blue sky and beautiful high cloud was about to be replaced by a westerly cloud front

The last data set of the day atop my car at the low point of the road

Once five minutes of data were gathered I packed the Trimble away, drove to a lay-by, changed and sorted my gear and headed down to the M4 for my onward journey to St David’s and tomorrow’s island adventure organised by Adrian Rayner.

Mapping Mountains – Trimble Surveys – Y Cymoedd

23.07.16  Mynydd Ton (SS 949 940 [SS 947 939, position Trimbled])    

Mynydd Ton (SS 949 940)

I’d visited Mynydd Ton once before in February 2003 when I followed the track leaving the A 4061 toward a forest break that gave relatively easy access toward where the 535m map heighted trig pillar was situated.  On that day I found ground about a minute away from the trig to be slightly higher, happy with my efforts I retraced my inward route back to my car.  Since my visit a number of Ordnance Survey maps have become available online, including the series of old Six-Inch maps and I believe it was Mick Moore who found a 1,769ft (539m) height on one of these maps that is adjoined to an ancient cairn which is approximately 175 metres south-west from where the trig pillar is positioned.  Therefore I wanted to re-visit the hill and the relatively newly discovered map high point.

As I left my car in a large lay-by near to the high point of the A 4061 the sun was out and young children were happily waiting next to an ice cream van as sheep also queued for any odd piece of food thrown their way.

The view north-east from the lay-by

A track leaves this road and heads up toward the forested summit area of Mynydd Ton, as I walked toward it two trail bikes were going through the gate and sped off across the hill’s northern flank, ahead was a car chugging its way up the track.  As I gained height there were other cars parked high on the track with a number of people flying model aircraft, I said my ‘hello’s’ and continued on the track to where it enters the forestry, I then turned right (southward) and followed a path beside the large conifer plantation to where a wide forest break gives access toward the map high point of the hill. 

Seemingly abandoned in the forest break was a four by four vehicle with its front windscreen partly smashed and its front end also badly damaged, I took a few photographs of it and continued down the forest break wanting to see if I could find the trig pillar that I’d previously visited, deciding that I’d had enough tree bashing for the day from my recent visit to Mynydd Ystradffernol, I back-tracked and headed in to another small forest break where the ancient cairn is situated and where the 1,769ft (539m) Six-Inch map heighted summit is positioned.

The abandoned four by four in the forest break

The cairn has been re-modelled and sits atop an ancient mound, past exploration found a central cist although this seems no longer in evidence.  I positioned the Trimble atop my rucksack deciding that the ground immediately beside the base of the cairn was slightly higher than the solid ground in the centre of it, and left it slowly ebbing down to its 0.1m accuracy level before data should be logged.  During this process I stood beside the trees and waited patiently, looking out past the re-modelled cairn and ancient mound to bright sunshine and the opposing conifers as they stared back at me.  I checked the equipment’s downward progress and once the accuracy level was attained I pressed ‘Log’ and retreated to the periphery of the trees and waited for five minutes of data to be collected.

Gathering data beside the ancient cairn on Mynydd Ton

The Trimble set-up position beside the ancient cairn on Mynydd Ton

As I packed the Trimble away I looked back at the mound and cairn and wondered if I would ever re-visit.  I then headed down the hill and visited the connecting bwlch which was just above where I had parked my car.  I’d examined this area via a Google car the previous evening and knew that a stone wall positioned on the south-eastward side of the road would give the Trimble elevation above its immediate surrounds.

Once at the top of the road which constitutes the area of the bwlch I judged the ground at the base of the wall to be the point of the critical bwlch and measured a 1.23m offset between the Trimble’s internal antenna and the ground at its base and set it to gather another five minute data set.  When it had collected its all-important data I walked the few metres down the road to my car and drove a kilometre westward toward my last hill of the day.

Gathering data at the critical bwlch of Mynydd Ton

  

Survey Result:

Mynydd Ton

Summit Height:  534.2m (converted to OSGM15) (significant height revision and summit relocated to its previously listed position; 534.4m at SS 94931 94059)  534.4m (converted to OSGM15, from subsequent Trimble survey)

Summit Grid Reference:  SS 94791 93954 (based on Trimble survey with the summit now relocated to SS 94931 94059)  SS 94931 94059 (from subsequent Trimble survey)

Bwlch Height:  443.1m (converted to OSGM15)

Bwlch Grid Reference:  SS 93953 94456

Drop:  91.1m (based on Trimble survey, 91.3m based on summit relocation and Subhump status confirmed)  91.3m (from subsequent Trimble survey)

Dominance:  17.08%



For details on the second summit survey of Mynydd Ton

For further details please consult the Trimble survey spreadsheet.

Mapping Mountains – Trimble Surveys – Cymoedd

23.07.16  Mynydd Ystradffernol (SN 937 009, not surveyed)    

Mynydd Ystradffernol (SN 936 009) with Fan Fawr and part of the Bannau Brycheiniog in the background

Mynydd Ystradffernol stands between the Rhondda Fach and Rhondda Fawr valleys and to its west its adjacent hill is Craig y Llyn; this being the highest hill in the south Wales valleys.  Since my last visit Mynydd Ystradffernol has undergone a transformation as the Pen y Cymoedd Wind Energy Project by Vattenfall has installed many wind turbines resulting in great swathes of conifered forestry being cut back.  This at least gives easier access to the area of the summit and also offers alternative routes to the top.

I set off on one of the forestry tracks that head toward the hill from the A 4061 as it crests its high point between Hirwaun to the north and Treherbert to the south.  I’d come prepared with a series of ten figure grid references for many forest track junctions and forest breaks which were situated  between my setting off point and the forest break that seemed to give easiest and quickest access to the high point of the hill.

It seemed unusual to see turbines poking up above the trees, I hadn’t been on this hill for a number of years and some hills significantly change over time, and this is one that is doing so as the wind energy project is not yet finished.

Reaching my cut off point I checked the grid reference for the forest break I wanted to take and headed up over horrendous tussocks in warmer and muggier conditions.  My going slowed as the tussocks proved unwelcome and it looked as if large parts of the forest break had once been covered in conifers resulting in small narrow ditches being hidden amongst the long grass.  However, bit by bit I gained height and decided to follow the very wide break around to my right where it seemed to penetrate the upper slopes of the hill the greatest, this was a mistake as it took me away from the summit in to the trees, I didn’t realise this at the time as all I was looking for was easiest passage to the summit.  It got to a point that I thought it more difficult to backtrack than go forward, so I carried on.  By now I was in the trees contouring around the upper part of the hill trying to get out on to open ground next to a wind turbine whose blades were on show sticking out above the trees.

I bashed through the last bit of conifers and popped out to sunshine and a few metres later was standing beside one of the newly installed wind turbines with the summit of the hill behind me to the west.  I was now much farther away from the summit when compared to where I’d been when on part of the forest break!

Not perturbed I decided that the wind turbines must be joined by tracks and as there was another one off in the distance close to where the summit was I headed in its direction.  However, I couldn’t find a connecting track but did find a forest break that took me in the right direction, only for two fallen trees to bar my progress; I bashed through them as best I could and emerged on the other side. 

Onward route through the trees

The forest break I was now on was close to the high point and I decided that I should at least gather data from two points adjacent to the trees on ground that rose in to them.  This took an inordinate amount of time as it took an age for the Trimble to ebb down to its 0.1m accuracy level before data should be logged.  Once two data sets were gathered I ventured in to the trees and wandered around visiting any high point I could find.

Gathering the first data set beside the trees on Mynydd Ystradffernol

Gathering the second data set beside the trees on Mynydd Ystradffernol

Once out of the trees I stumbled down to the nearest wind turbine and followed its adjacent track north-westward across the upper ridge of the hill toward two vehicles parked next to one of the turbines whose body was upright but whose blades were prostrate, awaiting the day of their instalment, they looked huge.

One of the blades for the wind turbines

Looking south south-east toward the summit of Mynydd Ystradffernol

As I approached this area another vehicle drove up the connecting track from the east, I flagged it down to check on the best track to use to get back on to the A 4061, within a few minutes I was sitting in the vehicle as it sped down the track, this gave me a rest from the forest and the trees and the thought of further conifer bashing.

I was fortunate to get a lift down the remainder of the forestry track

When we reached the A 4061 I thanked the driver and walked down the remainder of the road toward my awaiting car, next stop Mynydd Ton.

 

 

Hill's Details:

Mynydd Ystradffernol

Summit Height:  517.8m (converted to OSGM15, from subsequent Trimble survey)

Summit Grid Reference:  SN 93790 00902 (from subsequent Trimble survey)

Bwlch Height:  484.9m (converted to OSGM15, from subsequent Trimble survey) 

Bwlch Grid Reference:  SN 92961 02194 (from subsequent Trimble survey)

Drop:  32.9m (from subsequent Trimble survey)

Dominance:  6.35% (from subsequent Trimble survey)

For details on the summit and bwlch survey of this hill

For further details please consult the Trimble survey spreadsheet