Mapping Mountains – Significant Name Changes – 200m Twmpau and Y Trechol – The Dominant Hills of Wales

Coed y Bwnydd (SO 366 069)

There has been a Significant Name Change to a hill that is listed in the 200m Twmpau and the Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height and their locations, the drop, dominance and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Coed y Bwnydd (SO 366 069)

The criteria for the two listings that this name change applies to are:

200m Twmpau - Welsh hills at or above 200m and below 300m in height with 30m minimum drop, with an accompanying sub list entitled the 200m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 200m and below 300m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

200m Twmpau by Myrddyn Phillips

Y Trechol – The Dominant Hills of Wales – Welsh P30 hills whose prominence equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height.  The list is authored by Myrddyn Phillips with the Introduction to the start of the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and which is now available in its entirety on Mapping Mountains in Google Doc format.

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

The hill is adjoined to the Mynyddoedd Duon group of hills which are situated in the eastern part of South Wales (Region C, Sub-Region C3), and it is positioned with the Afon Wysg (River Usk) and the B4598 road to its west, the A40 road to its north and the A449 road to its east, and has the village of Raglan towards the east north-east and the town of Brynbuga (Usk) towards the south south-east.

When the original 100m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website this hill was listed under the name of Clytha Hill, which is a prominent name that appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map close to what was thought to be the summit of this hill.

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

LIDAR analysis has relocated the summit position of this hill from a 196m point that was given as two spot heights that are positioned close to where the name of Clytha Hill appears on contemporary Ordnance Survey maps to a higher 201.4m summit positioned at SO 36613 06919.  This higher summit is situated in woodland that is named on the map as Coed y Bwnydd.  This name appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and its position in relation to the summit of this hill is substantiated via the Ordnance Survey series of Six-Inch maps.

LIDAR summit image of Coed y Bwnydd (SO 366 069)

Extract from the Ordnance Survey series of Six-Inch maps

Therefore, the name this hill is now listed by in the 200m Twmpau and Y Trechol – The Dominant Hills of Wales is Coed y Bwnydd, and this name was derived from contemporary Ordnance Survey maps and its position in relation to the summit of this hill substantiated via the Ordnance Survey series of Six-Inch maps.  

The full details for the hill are:

Group:  Mynyddoedd Duon

Name:  Coed y Bwnydd

Previously Listed Name:  Clytha Hill 

  

OS 1:50,000 map:  161

Summit Height:  201.4m (LIDAR)

Summit Grid Reference:  SO 36613 06919 (LIDAR)

Bwlch Height:  59.4m (LIDAR)

Bwlch Grid Reference:  SO 39308 08901 (LIDAR)

Drop:  142.0m (LIDAR)

Dominance:  70.50% (LIDAR)

Myrddyn Phillips (February 2020)