Mapping Mountains – Hill Reclassifications – The Welsh Highlands – Uchafion Cymru

Moel Darren (SH 952 413) – Uchaf reclassified to 500m Sub-Uchaf

There has been a reclassification to the listing of The Welsh Highlands – Uchafion Cymru due to a Trimble GeoXH 6000 survey conducted by Myrddyn Phillips and Aled Williams on the 19^th January 2020.

Moel Darren (SH 952 413)

The criteria for the list that this reclassification applies to are:

The Welsh Highlands – Uchafion Cymru – This is the revised draft title for the Welsh 500m P15s list that takes in all hills in Wales at or above 500m in height with 15m minimum drop.  Accompanying the main list are three sub lists, these are; 500m Sub-Uchaf, 490m Sub-Uchaf and the Double Sub category, with this hill being reclassified to 500m Sub-Uchaf status, the criteria for which are all Welsh hills at or above 500m in height with 14m or more and below 15m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams with the Introduction to the list being published on Mapping Mountains in November 2015 and an update relating to the list appearing on Mapping Mountains on the 19^th June 2019.

The name the hill is listed by is Moel Darren and it is adjoined to the Arenig group of hills, which are situated in the central part of North Wales (Region A, Sub-Region A3), and it is positioned with the A5 road to its north-east, the B4501 road to its west and the A494 road to its south-east, and has the town of Y Bala towards the south south-west and the village of Cerrigydrudion towards the north.

This hill was not included in the original list of Welsh 500m P15s that later became known as Yr Uchafion and latterly as The Welsh Highlands – Uchafion Cymru, however it was listed as a potential qualifying hill as it has a 509m summit spot height on contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps and bwlch contouring between 490m – 500m.

Extract from the Ordnance Survey 1:25,000 Explorer map

This hill was subsequently surveyed using a basic levelling staff on the 1^st May 2004 by Myrddyn Phillips, resulting in a 51½ft / 15.7m drop value, which was sufficient for it to be classified as an Uchaf.

However, as the margin of uncertainty applicable to the basic levelling method of surveying over the distance between bwlch and summit and the terrain of this hill is approximately +/- 1m, the hill was prioritised for an accurate survey.

The Trimble GeoXH 6000 gathering data at the summit of Moel Darren

The Trimble GeoXH 6000 gathering data at the bwlch of Moel Darren

Therefore, the reclassification of Moel Darren to 500m Sub-Uchaf status is due to a survey with the Trimble GeoXH 6000, resulting in a 510.0m summit height and a 495.4m bwlch height, with these values giving this hill 14.6m of drop which is insufficient for it to be retained as an Uchaf.

The full details for the hill are:

Group:  Arenig

Name:  Moel Darren

OS 1:50,000 map:  125

Summit Height:  510.0m (converted to OSGM15)

Summit Grid Reference:  SH 95221 41372

Bwlch Height:  495.4m (converted to OSGM15)

Bwlch Grid Reference:  SH 95185 41686

   

Drop:  14.6m 

For the additions, deletions and reclassifications to The Welsh Highlands – Uchafion Cymru reported on Mapping Mountains please consult the following Change Registers:

The Welsh 500m P15s (Yr Uchafion)

The Welsh 500m P15s (Yr Uchafion) – 500m Subs

The Welsh 500m P15s (Yr Uchafion) – 490m Subs

The Welsh 500m P15s (Yr Uchafion) – Double Subs

Aled Williams and Myrddyn Phillips (June 2020)