Mapping Mountains – Hill Reclassifications – Y Trechol – The Dominant Hills of Wales

Coed Cae Maen (ST 362 998) – Lesser Dominant deletion

There has been a deletion to the listing of 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 Cae Maen (ST 362 998)

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

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.

The name the hill is now listed by is Coed Cae Maen and this was derived from the Tithe map, and it is adjoined to the Cymoedd Gwent group of hills, which are situated in the eastern part of South Wales (Region C, Sub-Region C2), and it is encircled by minor roads with the A472 road further to its north and the A449 road further to its east, and has the town of Brynbuga (Usk) towards its north-east.

When the original 100m height band of Welsh P30 hills published on Geoff Crowder’s v-g.me website were standardised and interpolated heights also included, this hill was listed with an estimated c 34m of drop and 33.66% dominance, based on an estimated c 101m summit height and an estimated bwlch height of c 67m, with these heights based on 10m contour intervals on the Ordnance Survey 1:25,000 Explorer map.

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. 

The summit height produced by LIDAR analysis is 101.0m and is positioned at ST 36203 99841, and the bwlch height is 67.6m and is positioned at ST 35963 99882, with these values giving this hill 33.5m of drop and 33.12% dominance which is insufficient for its continued inclusion as a Lesser Dominant hill.

The full details for the hill are:

Group:  Cymoedd Gwent

Name:  Coed Cae Maen

OS 1:50,000 map:  171

Summit Grid Reference:  ST 36203 99841 (LIDAR)

Summit Height:  101.0m (LIDAR)

Bwlch Grid Reference:  ST 35963 99882 (LIDAR)

Drop Summit to Bwlch:  33.5m (LIDAR)

Drop Bwlch to ODN:  67.6m (LIDAR)

Dominance:  33.12% (LIDAR)

Myrddyn Phillips (August 2019)