Mapping Mountains – Hill Reclassifications – Y Trichant

Cwm Faerdy Bank (SO 078 695) – Sub-Trichant reclassified to Trichant

There has been confirmation of a reclassification to the list of Y Trichant, with this initiated from LIDAR analysis and then confirmed by a Trimble GeoXH 6000 survey conducted by Myrddyn Phillips, with the lattet taking place on the 10^th July 2018.

Cwm Faerdy Bank (SO 078 695)

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

Y Trichant – 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 its renaming appearing on Mapping Mountains on the 13^th May 2017.

When the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website this hill appeared in the accompanying Hills to be surveyed sub list as it did not meet the criteria then used for the main P30 list; however this sub list has now been standardised and interpolated heights also included in the main P30 and the accompanying sub list.

When this list was standardised and interpolated heights also included this hill was listed with an estimated c 30m of drop, based on the 302m spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 372m based on interpolation of bwlch contouring between 270m – 280m.  These details were re-examined when the Ordnance Survey Interactive Coverage Map hosted on the Geograph website became available online and the drop value was then amended to c 31m.

The name of the hill is Cwm Faerdy Bank, and this was derived from local enquiry, and it is adjoined to the Pegwn Mawr range of hills which are situated in the north-eastern part of Mid and West Wales (Region B, Sub-Region B1), and it is positioned with the Clywedog Brook to its west and the Afon Ieithon (River Ithon) to its east, and has the small community of Abaty Cwm-hir (Abbeycwmhir) towards the north-west. 

If wanting to visit the summit of the hill permission to do so should be sought as it is not a part of designated open access land, for those wishing to do so a public footpath approaches the hill from the north and east with the continuation of a track from where these footpaths meet leading toward the summit of the hill.

The confirmation of the reclassification of Cwm Faerdy Bank to Y Trichant status is due to LIDAR analysis conducted by Myrddyn Phillips.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.  

LIDAR image of Cwm Faerdy Bank

The LIDAR analysis gives the hill the following details:

Name:  Cwm Faerdy Bank

Summit Height:  302.2m

Summit Grid Reference:  SO 07843 69513

Bwlch Height:  269.8m

Bwlch Grid Reference:  SO 08305 69665

Drop:  32.3m

Therefore, the 302.2m LIDAR analysis for the summit position at SO 07843 69513 and the 269.8m LIDAR analysis for the bwlch position at SO 08305 69665 gives this hill 32.3m of drop, with the details from the Trimble GeoXH 6000 survey being 302.3m (converted to OSGM15) summit at SO 07842 69512 and 269.9m (converted to OSGM15) bwlch at SO 08304 69664, giving this hill 32.4m of drop which confirms its Trichant status.

The Trimble GeoXH 6000 gathering data at the summit of Cwm Faerdy Bank

The full details for the hill are:

Group:  Pegwn Mawr

Name:  Cwm Faerdy Bank

OS 1:50,000 map:  136, 147

Summit Height:  302.3m (converted to OSGM15)

Summit Grid Reference:  SO 07842 69512

Bwlch Height:  269.9m (converted to OSGM15)

Bwlch Grid Reference:  SO 08304 69664

Drop:  32.4m (converted to OSGM15)

For details on the survey of Cwm Faerdy Bank

Myrddyn Phillips (December 2018)