Mapping Mountains – Hill Reclassifications – 200m Twmpau

Erw Penlan (SO 045 495) – 200m Sub-Twmpau addition

There has been a confirmation of an addition to the 200m Twmpau (thirty welsh metre prominences and upward) ranks of hills due to a survey with the Trimble GeoXH 6000, with the survey that confirmed this addition being conducted on the 13^th June 2017.

The criteria for 200m Twmpau status is all 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, and it is the inclusion of this hill in the 200m Sub-Twmpau that has been confirmed. 

The hill did not appear in the original Welsh P30 lists on Geoff Crowder’s v-g.me website as it did not meet the criteria then adopted for the Hills to be surveyed sub list.  The hill was later classified and listed in the sub category after this was standardised and interpolated drop values added, and was included when the updates to the 200m Welsh P30s were published for the Mynydd Epynt group of hills on Mapping Mountains on the 25^th August 2014.  The listing this hill is now a part of is named Twmpau (thirty welsh metre prominences and upward) and its height, drop and status was confirmed by a survey with the Trimble GeoXH 6000.   

Prior to the survey with the Trimble GeoXH 6000 the hill was listed by the name of Coetgae Fawr with an estimated c 21m of drop, based on the 213m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 192m based on interpolation of bwlch contouring between 190m – 200m.

The name that this hill is being listed by is Erw Penlan (see Significant Name Changes) and it is adjoined to the Mynydd Epynt range, which is situated in the south-eastern part of Mid and West Wales (Region B, Sub-Region B2) with its Cardinal Hill being Clepyn Melyn (SN 961 464), and it is positioned above the A 483 road which is to the hill’s north and east, with the town of Llanfair-ym-Muallt (Builth Wells) positioned to its north.

As the hill does not form a part of designated open access land permission to visit should be sought, for those wishing to do so a public footpath connects between minor country lanes to the north and south of the hill’s summit and proceeds around the upper western part of the hill.

The full details for the hill are:

Cardinal Hill:  Clepyn Melyn

Summit Height:  212.1m (converted to OSGM15)

Name:  Erw Penlan

OS 1:50,000 map:  147

Summit Grid Reference:  SO 04597 49535  

Drop:  20.9m (converted to OSGM15)

Erw Penlan (SO 045 495) now confirmed as a 200m Sub-Twmpau addition

For details on the survey that confirmed the addition of this hill to 200m Sub-Twmpau status

Myrddyn Phillips (August 2017)