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)