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

Pt. 581.7m (SJ 086 373) – 500m Sub-Uchaf deletion 

There has been a deletion to the listing of The Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill derived from a Trimble GeoXH 6000 survey conducted by Myrddyn Phillips and Aled Williams. 

Pt. 581.7m (SJ 086 373)

The criteria for the list that this deletion 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 deleted as a 500m Sub-Uchaf.  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 Welsh Highlands - Uchafion Cymru by Myrddyn Phillips and Aled Williams

As the authors do not know an appropriate name for the hill either from historic research or from local enquiry it is being listed by the point (Pt. 581.7m) notation, and it is adjoined to the Y Berwyn group of hills, which are situated in the south-eastern part of North Wales (Region A, Sub-Region A4), and it is positioned with the A5 road to its north, the B4401 road to its west and the B4391 road to its south-west, and has the village of Cynwyd towards the north-west. 

This hill was not included as a P14 Sub in the original list of Welsh 500m P15s that later became known as Yr Uchafion and latterly as The Welsh Highlands – Uchafion Cymru, as with a 582m summit spot height and bwlch contouring between 570m – 580m that appear on the Ordnance Survey 1:25,000 Explorer map, this contouring implied that the hill did not have sufficient drop to be considered for P14 500m Sub-Uchaf status. 

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

Since the original compilation of this list there are now a number of interactive maps originated from Ordnance Survey data that are available online.  One of these is the mapping on the OS Maps website.  This is the replacement for OS Get-a-map and used to have contours at 5m intervals which proved consistently more accurate compared to the 5m contours that sometimes appear on the Ordnance Survey 1:25,000 Explorer map and used to appear on the online Vector Map Local.  This mapping had an uppermost 580m ring contour and bwlch contouring between 565m – 570m, with interpolation giving an estimated bwlch height of c 568m, therefore with an estimated c 14m of drop it was added as a 500m Sub-Uchaf.  Due to this addition the hill was prioritised for a Trimble GeoXH 6000 survey and this has now taken place resulting in its deletion from sub status. 

The Trimble GeoXH 6000 gathering data at the summit of Pt. 581.7m

The Trimble GeoXH 6000 gathering data at the bwlch of Pt. 581.7m

Therefore, the deletion of this hill from 500m Sub-Uchaf status is due to a Trimble GeoXH 6000 survey, resulting in a 581.7m summit height and a 568.7m bwlch height, with these values giving this hill 13.0m of drop, which is insufficient for it to be classified as a 500m Sub-Uchaf. 

 

The full details for the hill are: 

Group:  Y Berwyn

Name:  Pt. 581.7m

OS 1:50,000 map:  125

Summit Height:  581.7m (converted to OSGM15)

Summit Grid Reference:  SJ 08664 37360

Bwlch Height:  568.7m (converted to OSGM15)

Bwlch Grid Reference:  SJ 08659 37320   

Drop:  13.0m 

 

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

 

Myrddyn Phillips and Aled Williams (June 2020)