Mapping Mountains – Summit Relocations – 100m Twmpau

Pentre Clawdd Gorse (SJ 311 442)  

There has been a Summit Relocation to a hill is now listed in the 100m Twmpau (thirty welsh metre prominences and upward) due to a survey with the Trimble GeoXH 6000 conducted by Myrddyn Phillips and which took place on the 23^rd February 2016.

The name of the hill is Pentre Clawdd Gorse and it is positioned in the eastern part of the Moel y Gamelin range of hills, and situated to the east of the A 483 and north-east of the town of Rhiwabon (Ruabon).  Access to the hill is relatively easy as its summit is positioned on Wat’s Dyke, this ancient earthwork stretches from the Dee estuary in the north to Shropshire in the south, and public footpaths follow its course over this hill’s broad north – south summit ridge.

Pentre Clawdd Gorse is adjoined to the summit of Wynnstay Park (SJ 31001 42958) which is approximately one kilometre due south from it, with the latter having a 141m spot height given it on Ordnance Survey 1:25,000 Explorer maps.  The summit of Wynnstay Park was surveyed on the 20^th October 2015 with the Trimble GeoXH 6000 and subsequently analysed via LIDAR, resulting in a 141.2m summit height.

LIDAR image of Pentre Clawdd Gorse (SJ 311 442)

As the summit of Pentre Clawdd Gorse was surveyed as 0.8m higher than Wynnstay Park, and as the latter was listed in the Hills to be surveyed sub list that accompanied the original Welsh 100m P30 listings on Geoff Crowder’s v-g.me website, and as the height of the bwlch between these two hills in only 128.2m, the summit of the qualifying hill has been relocated to that of Pentre Clawdd Gorse.

Therefore, the position of the relocated summit is at SJ 31131 44252 and is situated on the highest point of this part of the ancient earthwork known as Wat’s Dyke.  Either side of this earthwork are fields, one given over to grazing and the other which is arable.  This part of Wat’s Dyke has a narrow line of mature trees growing on it which adds perspective and interest to the landscape, although their proximity hampered satellite reception.  This position is not given a spot height on contemporary Ordnance Survey maps and has an uppermost contour ring of 140m, and is approximately 1.4 kilometres northward of the summit of Wynnstay Park.

 

The full details for the hill are:

Group:  Moel y Gamelin

Name:  Pentre Clawdd Gorse

OS 1:50,000 map:  117

Summit Height:  142.0m (converted to OSGM15)

Summit Grid Reference (New Position):  SJ 31131 44252 

  

Bwlch Height:  109.8m (LIDAR)

Bwlch Grid Reference:  SJ 30789 44141 (LIDAR)

Drop:  32.2m (Trimble summit and LIDAR bwlch)

The Trimble GeoXH 6000 gathering data at the summit of Pentre Clawdd Gorse, with the summit of Wynnstay Park on the left and in the background of this photograph

For details on the survey that relocated the summit of this hill please click {here}

Myrddyn Phillips (February 2016)

Mapping Mountains – Hill Reclassifications – 100m Twmpau

Pentre Clawdd Gorse (SJ 311 442) - 100m Twmpau addition  

There has been an addition of a hill to the list of 100m Twmpau (thirty welsh metre prominences and upward) instigated by a summit survey with the Trimble GeoXH 6000 and subsequent LIDAR bwlch analysis.   The hill is situated to the east of the A483 road and to the north-east of Rhiwabon (Ruabon) in the eastern part of the Moel y Gamelin range of hills.

LIDAR image of Pentre Clawdd Gorse (SJ 311 442)

The Trimble GeoXH 6000 survey that initiated this hill’s addition to the 100m Twmpau list was conducted in the afternoon of the 23^th February 2016 on a beautiful winter’s day in good, dry and sunny conditions.

The name the hill is listed by is Pentre Clawdd Gorse and access to it is relatively easy as its summit is positioned on Wat’s Dyke, this ancient earthwork stretches from the Dee estuary in the north to Shropshire in the south, and public footpaths follow its course over this hill.

Pentre Clawdd Gorse is adjoined to the summit of Wynnstay Park (SJ 31001 42958) which is approximately one kilometre due south from it, with the latter having a 141m spot height given it on Ordnance Survey 1:25,000 Explorer maps.  The summit of Wynnstay Park was surveyed on the 20^th October 2015 with the Trimble GeoXH 6000 and subsequently analysed via LIDAR, resulting in a 141.2m summit height.

The survey with the Trimble GeoXH 6000 resulted in a summit height of 142.0m, giving Pentre Clawdd Gorse as 0.8m higher than Wynnstay Park.  The area of the bwlch was analysed via LIDAR resulting in a 109.8m height, with these values giving this hill 32.2m of drop, which is sufficient for this hill to be classified as a 100m Twmpau. 

The full details for the hill are:

Group:  Moel y Gamelin

Name:  Pentre Clawdd Gorse

OS 1:50,000 map:  117

Summit Height:  142.0m (converted to OSGM15)

Summit Grid Reference:  SJ 31131 44252 

  

Bwlch Height:  109.8m (LIDAR)

Bwlch Grid Reference:  SJ 30789 44141 (LIDAR)

Drop:  32.2m (Trimble summit and LIDAR bwlch)

The summit of Pentre Clawdd Gorse (SJ 311 442) the new addition to the 100m Twmpau list

For details on the survey that resulted in this hill being added to the 100m Twmpau list please click {here} for summit and {here} for the bwlch survey.

Myrddyn Phillips (February 2016)

Mapping Mountains – Trimble Surveys – Moel y Gamelin

23.02.16  Pentre Clawdd Gorse (SJ 311 442)  

Pentre Clawdd Gorse (SJ 311 442) is the wooded summit on the left of this photograph

The summit of Pentre Clawdd Gorse is linked with that of Wynnstay Park (SJ 310 429) which is an approximate kilometre due south, and the latter was Trimbled on the 20^th October 2015.  During that survey I thought that Wynnstay Park was the highest summit in the area that connected to the bwlch at SJ 307 441.  It was only later when examining a number of maps that I noticed that Pentre Clawdd Gorse had two small 140m ring contours at its summit, and as Wynnstay Park was Trimbled as being 141.2m high and its drop to a natural bwlch at SJ 307 437 being surveyed as 29.5m, it meant that Pentre Clawdd Gorse could be the higher summit, and if it was surveyed as being 0.5m higher than Wynnstay Park it would also become Wales’ newest P30.

Wynnstay Park (SJ 309 429) from close to the summit of Pentre Clawdd Gorse

Parking next to the Broth Lodge I walked back across the A 539 toward a foot stile giving access to a footpath and field on the north side of the road.  I’d used this same footpath when surveying the natural bwlch in October of last year, then I’d followed the field ridge fence and connected with another footpath which brought me down to the area of the bwlch, today I remained in the field and followed its ridge northward beside the remains of a section of Wat’s Dyke.

The view over the hedge on the roadside with Wat's Dyke following the left hand ridge from the wooded summit of Pentre Clawdd Gorse

Wat’s Dyke is an earthwork approximately 64 km (40 miles) in length and which straggles the countryside between Maesbury in Shropshire in the south and Basingwerk Abbey near to the River Dee estuary in the north.  For much of this distance it runs parallel with its more famous cousin; Offa’s Dyke.

I hoped that the high point of the first of the two 140m ring contours was not obstructed by undergrowth and trees, as this may prove problematic for satellite reception.  As I gained height I left the field and walked on the Dyke, still following the footpath as it continued through the tree lined canopy.  The first high point proved relatively easy to identify and although it was positioned under a number of trees it had a fairly good view of the sky.  I set the Trimble up on my rucksack and waited in the field below, from this vantage point the Dyke rose by at least 2m from its base and as the 140m ring contour took in the base of the earthwork I thought its height would be sufficient for the hill to gain P30 status.

The Trimble is placed on top of my rucksack and on the high point of Pentre Clawdd Gorse which is a part of the ancient earthwork of Wat's Dyke and which is at least 3m higher than the field at its base

After ten minutes or so the accuracy level attained 0.1m and I pressed Log, and scampered down the bank to wait in the field below.  To my west the continuous hum of traffic on the A483 road steadily meandered its way through the otherwise tranquil countryside.  After pressing the ‘Done’ button on the Trimble I took a number of photographs of it perched on my rucksack at the high point of this section of Wat’s Dyke.

Gathering data from the summit of Pentre Clawdd Gorse

My next and last objective of the day was the second 140m ring contour; this is placed at the top of a turnip field which conveniently has a footpath crossing it close to its summit.  As the Trimble gathered its data I stood admiring the colour cast down on the surrounding land as the afternoon light lit all around.  Just before closing the Trimble down I noticed another high point buried behind a holly tree, this seemed unusually shaped, but when I walked to it, it was solid underfoot, this meant one last Trimble survey was necessary for me to walk away happy in the knowledge that all summit contenders had been surveyed.

Gathering data in a field full of turnips and which constitutes where the second 140m ring contour is placed, with the summit of Pentre Clawdd Gorse in the background on the left of this photograph

This last survey took an age as the Trimbe was obstructed by a canopy of mature trees, I waited patiently for about 15 – 20 minutes until the 0.1m accuracy level appeared before data should be logged, once this magical mark appeared on the screen, I quickly pressed Log and stood behind the trees and waited for five minutes of data to be collected.

The last data set of the day proved to be where an old quarry is marked on old maps

Balanced on top of a solid mound of earth the Trimble gathers its last data set of the day

Looking toward where the second 140m ring contour appears on the ground with the remains of the old quarry hidden in the trees

On my way back I chatted with a man who was out walking his two dogs, I’d noticed him from afar and on my way down the field he had stood motionless, just looking east, taking in the view and the light, when I approached we said our hello’s and both commented what a beautiful afternoon it was.  And indeed it was, a glow was cascading down upon the landscape, a rather magical late afternoon winter’s glow that percolated one’s need to be out in such surroundings and brought a contented happiness to one’s being.     

Survey Result:

Pentre Clawdd Gorse

Summit Height:  142.0m (converted to OSGM15, Trimble GeoXH 6000 and confirmed as higher than Wynnstay Park [SJ 31001 42958])

Summit Grid Reference:  SJ 31131 44252 (Trimble GeoXH 6000) (summit relocation confirmed)

Bwlch Height:  109.8m (LIDAR)

Bwlch Grid Reference:  SJ 30789 44141 (LIDAR)

Drop:  32.2m (Trimble GeoXH 6000 summit and LIDAR bwlch) (100m Twmpau addition)

Dominance:  22.67% (Trimble GeoXH 6000 summit and LIDAR bwlch)  

Postscript:  It had been a good day on the hill, with four places visited and an impressive reclassification hit rate achieved as evidenced below:

Parc y Borth (SH 558 375) – reclassified from a Dominant to a Lesser Dominant.

Moel y Gadair (SH 521 391) – reclassified from a 30–99m Twmpau to a 30-99m Sub-Twmpau, and also deleted from the Lesser Dominant list.

Pt. 258m (SH 811 542) – Re-instated as a 200m Twmpau from a 200m Sub-Twmpau.

Pentre Clawdd Gorse (SJ 311 442) – new 100m Twmpau.

For the post detailing the bwlch survey of Pentre Clawdd Gorse please click {here}

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

Mapping Mountains – Trimble Surveys – Moel y Gamelin

20.10.15  Wynnstay Park (SJ 310 429) and Pentre Clawdd Gorse (SJ 311 442), only bwlch surveyed   

The grounds of Wynnstay Park

The Wynnstay Estate was the family seat of the Wynns, a family whose land owning prowess included much of the southern part of north Wales.  The main house on this old estate has now been converted to flats and private houses.  The high point of Wynnstay Park is a potential P30 with a summit spot height of 141m and a bwlch spot height that is not centred on the valley to valley traverse of 113m, with another summit ; Pentre Clawdd Gorse (SJ 311 442) being potentially higher.

I parked beside the entrance to the estate grounds at SJ 311 433 next to Broth Lodge, leaves crisped under my feet and an occasional car passed me as I quickly marched to the top of the paved road leading to the old estate house.  The 141m map spot height appears on the north-eastern side of an intersection, visually the land to the south-west of this intersection looked higher.

As I continued toward where I thought the highest ground to be situated I watched a photographer frame a shot of autumnal trees above their fallen leaves, I stopped and we chatted, I looked through the viewfinder of his camera and the composition looked stunning, my photo taken from the same position looks drab in comparison.  I explained what I hoped to do and asked him where he thought the highest ground to be positioned, he looked around and pointed toward the place where I had independently also judged the summit of Wynnstay Park to be situated.

I placed the Trimble on top of my rucksack and the long waiting game began.  After about ten minutes the Trimble’s accuracy level was struggling to make 0.35m, so I switched it off and created a new file and set it up facing in a different direction but still aligned over the high point.  I then stood back and waited………. and waited……….. and waited.

During this time I took a number of photos of trees and a ‘Caution Squirrels Crossing’ sign.  It took an age for the Trimble to achieve its required 0.1m accuracy level before data should be logged, but once it had I quickly pressed ‘Log’ and waited for the five minutes of data collection to be complete.

This sign amused me during my long wait for the Trimble to achieve its 0.1m accuracy level before data should be logged

The Trimble set-up position at Wynnstay Park

By now the sun was low on the horizon and once the Trimble was packed away I scampered off down the road, past my car and on to a footpath that led over a field toward the first of two bwlch surveys I wanted to complete.  This first potential bwlch position was in a grassed field with an enclosed footpath next to it and allotments in front of it.  As the Trimble gathered data I chatted with a couple of people who were out walking their dogs, one kindly pointed me in the right direction for easiest access toward the footpath near to where I wanted to gather the second potential bwlch data set.

Gathering data at the first of two set up positions for the bwlch

This second position was in another grassed field with a graveled track adjacent to it and separated from it by a large hedge.  As the Trimble gathered its 14^th and last data set of the day I stood uphill of it and peered down on the field and looked at the land as it continued its downward progress from where the Trimble was quietly beeping away.

Gathering data at the second of two set up positions for the bwlch

Once the Trimble was packed away I followed the footpath from the graveled track uphill to the field and my inward route back to my car.  It had been another good day visiting hills made out of mine spoil and ones luxuriating themselves in country parks.

The paved road leading toward the summit of Wynnstay Park 

Survey Result:

Wynnstay Park

Summit Height:  141.2m (LIDAR, and confirmed as lower than Pentre Clawdd Gorse [SJ 31131 44252])

Summit Grid Reference:  SJ 31001 42958 (LIDAR) (summit relocation)

Bwlch Height:  128.2m (LIDAR)

Bwlch Grid Reference:  SJ 31418 43293 (LIDAR)

Drop:  13.0m (LIDAR)

Dominance:  9.22% (LIDAR)

Pentre Clawdd Gorse

Summit Height:  142.0m (converted to OSGM15, from subsequent Trimble GeoXH 6000 survey and confirmed as higher than Wynnstay Park [SJ 31001 42958])

Summit Grid Reference:  SJ 31131 44252 (from subsequent Trimble GeoXH 6000 survey) (summit relocation confirmed)

Bwlch Height:  109.8m (LIDAR)

Bwlch Grid Reference:  SJ 30789 44141 (LIDAR)

Drop:  32.2m (Trimble GeoXH 6000 summit and LIDAR bwlch) (100m Twmpau addition)

Dominance:  22.67% (Trimble GeoXH 6000 summit and LIDAR bwlch)

  

For the post detailing the summit survey of Pentre Clawdd Gorse

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