Mapping Mountains – Summit Relocations – Y Trichant – The 300m Hills of Wales

 

Foel Fawr (SH 679 057) 

There has been a Summit Relocation to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their location, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Foel Fawr (SH 679 057)

The criteria for the list that this summit relocation applies to are: 

Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant, with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13^th May 2017, and the Introduction to the Mapping Mountains publication of the list appearing on the 1^st January 2022. 

Y Trichant - The 300m Hills of Wales by Myrddyn Phillips

The name the hill is listed by is Foel Fawr, and it is adjoined to the Tarren y Gesail group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), and it is positioned with the B4405 road to its north-west and a minor road to its north-east, and has the town of Machynlleth towards the south-east. 

When the original 300m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was listed with a 348m summit height, based on the spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and which is positioned at SH 67959 05849. 

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 summit image of Foel Fawr (SH 679 057)

The summit height produced by LIDAR analysis is 343.9m and is positioned at SH 67982 05743, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are: 

The term Summit Relocations applies to when the high point is positioned in a different field, to a different feature such as a conifer plantation, within a different map contour, a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is considered a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist. 

Therefore, the summit height produced by LIDAR analysis is 343.9m and this is positioned at SH 67982 05743, this position is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, and is approximately 110 metres southward from where the previously listed summit is positioned. 

 

The full details for the hill are:

Group:  Tarren y Gesail 

Name:  Foel Fawr 

OS 1:50,000 map:  124

Summit Height:  343.9m (LIDAR)                                                           

Summit Grid Reference (New Position):  SH 67982 05743 (LIDAR) 

Bwlch Height:  286.5m (LIDAR) 

Bwlch Grid Reference:  SH 67651 05532 (LIDAR) 

Drop:  57.4m (LIDAR) 

 

Myrddyn Phillips (March 2022)