Mapping Mountains – Summit Relocations – 200m Twmpau and Y Trechol - The Dominant Hills of Wales

Pen y Berth (SJ 081 127)  

There has been a Summit Relocation to the 200m Twmpau (thirty welsh metre prominences and upward) list and also the Y Trichant - The Dominant Hills of Wales list due to a survey with the Trimble GeoXH 6000, and these details are retrospective as the survey that resulted in this summit relocation was conducted on 19^th October 2014.

The survey was conducted in the hills just to the east of the small community of Dolanog, with the hill positioned above the B4382 which is to its south, and above the Afon Efyrnwy which is to its north.

The hill was surveyed in the company of Mark Trengove on a day when the westerly showers were being pushed east; thankfully all missed us as we visited two hills over two separate walks.

The hill is named Pen y Berth, and its prioritised summit position was listed at SJ 080 127 as this is where its 282m summit spot height appears on the Ordnance Survey enlarged mapping hosted on the Geograph website.  This map also shows a twin 282m map heighted summit at SJ 083 127.

The position of the spot height at SJ 080 127 is immersed in a conifer plantation, whilst the position of the spot height at SJ 083 127 is on open ground with small deciduous trees growing near to it.  The latter position was surveyed with the Trimble GeoXH 6000 as was a position on the periphery of the conifer plantation that was visually higher than the remaining ground within the forestry.

The result of each survey appears below:

282m spot height at SJ 083 127 came to 283.7m (converted to OSGM15) at SJ 08322 12748

new summit position came to 287.5m (converted to OSGM15) at SJ 08126 12730

282m spot height at SJ 080 127 was not surveyed as its position was deemed lower compared to the new summit position

The position of the relocated summit is at SJ 08126 12730 and is the top of featureless ground under Larch trees, this is not given a spot height on current Ordnance Survey maps but the Trimble result gave it as 5.5m higher and approximately 80 metres eastward from where the westerly 282m map spot height is positioned on the ground.

The full details for the hill are:

Cardinal Hill:  Carreg y Big

Summit Height:  287.5m (converted to OSGM15)

Name:  Pen y Berth

OS 1:50,000 map:  125

Summit Grid Reference (New Position):  SJ 08126 12730 

 

Drop:  134.2m (converted to OSGM15)

Dominance:  46.68%

The Trimble GeoXH 6000 set up at the new summit position of Pen y Berth, with the old position of the prioritised summit approximately 80 metres behind the Trimble and further into the conifer plantation

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

Myrddyn Phillips (October 2014)