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

Drum Boeth (SH 717 464) - Uchaf addition

There has been an addition to the listing of Yr Uchafion, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Aled Williams, with a subsequent Trimble Ge0XH 6000 survey conducted by Myrddyn Phillips and Aled Williams confirming its status.

Drum Boeth (SH 717 464)

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

Yr Uchafion (Latterly named The Welsh Highlands - Uchafion Cymru) - This is the draft title for a list of the Welsh 500m P15s that takes in all Welsh hills at or above 500m in height that have a minimum 15m of drop.  Accompanying the main list are three sub lists; the 500m Sub-Uchaf, 490m Sub-Uchaf and the Double Sub-Uchaf category.  The criteria for 500m Sub-Uchaf status is all Welsh hills at or above 500m in height that have 14m or more and below 15m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams, with the details relating to this list published on the Mapping Mountains site in November 2015.

The Welsh Highlands - Uchafion Cymru by Aled Williams and Myrddyn Phillips

The name the hill is listed by is Drum Boeth, and it is adjoined to the Arenig Fach group of hills, which are situated in the central part of North Wales (Region A, Sub-Region A2), and it is positioned with the A470 road to its south-west, and has the town of Blaenau Ffestiniog towards the west south-west. 

This hill is given an uppermost 520m ring contour with no spot height on the contemporary Ordnance Survey 1:25,000 Explorer map, with bwlch contouring between 490m – 500m and prior to LIDAR analysis it was not classified.

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

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

LIDAR analysis resulted in the addition of this hill to Uchaf status.  The hill has subsequently been surveyed using the Trimble GeoXH 6000, and it is this result that is being prioritised for listing purposes.

Gathering data at the summit of Drum Boeth

The Trimble atop my rucksack gathering data at the bwlch of Drum Boeth

Therefore, the addition of this hill to Uchaf status is due to LIDAR analysis, with a subsequent Trimble GeoXH 6000 survey confirming its status, resulting in a 506.8m summit height and a 490.4m bwlch height, with these values giving this hill 16.4m of drop, which is sufficient for Uchaf status.  

The full details for the hill are:

Group:  Arenig Fach

Name:  Drum Boeth

OS 1:50,000 map:  115

Summit Height:  506.8m (converted to OSGM15)

Summit Grid Reference:  SH 71724 46417

   

Bwlch Height:  490.4m (converted to OSGM15)

Bwlch Grid Reference:  SH 71823 46452

Drop:  16.4m

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

 

Welsh Highland P15s

 

Welsh Highland Subs

Myrddyn Phillips and Aled Williams (April 2017)