Mapping Mountains – Hill Reclassifications – Y Pedwarau

Fuches (SN 866 836) – 400m Sub-Pedwar reinstated to Pedwar

There has been a reclassification to the listing of Y Pedwarau due to a survey with the Trimble GeoXH 6000 which took place on the 03.06.18.  Y Pedwarau is the title for the list of 400m hills of Wales and takes in all Welsh hills at or above 400m and below 500m in height that have a minimum 30m of drop, the list is a joint compilation between Myrddyn Phillips and Aled Williams and it commenced publication on Mapping Mountains on the 30.01.17.

Accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being reclassified from a 400m Sub-Pedwar to a Pedwar.  The criteria for 400m Sub-Pedwar status is all Welsh hills at or above 400m and below 500m in height that have 20m or more and below 30m of drop.

The name of the hill is Fuches and prior to the Trimble GeoXH 6000 survey it was listed with 27.5m of drop, based on LIDAR analysis giving a 446.7m summit and 419.2m bwlch height.  This hill’s adjacent peak of Allt y Derw (SN 873 834) was also analysed using LIDAR resulting in a 449.9m summit height.  As LIDAR gave Allt y Derw as higher the respective bwlch positions and heights of these two hills were swapped resulting in Fuches being reclassified to a 400m Sub-Pedwar.  This hill was then re-analysed via LIDAR by Chris Crocker resulting in a different conclusion, therefore the DSM LIDAR model was re-analysed resulting in the conclusion that Fuches was a marginal Pedwar and the Trimble GeoXH 6000 survey was done to confirm this, resulting in the classification of this hill reversing to pre LIDAR analysis, with the caveat that Allt y Derw is being listed as the higher of the two hills.

The hill is a part of the Pumlumon range with its Cardinal Hill being Pumlumon Fawr (SN 789 869) and is placed in the Region of Mid and West Wales (Region B, Sub-Region B2).  The hill is situated between the stream valleys of the Afon Hafren (River Severn) to the north-east and the Afon Gwy (River Wye) to the south, and has the small community of Llangurig towards the south-east. 

Fuches (SN 866 836)

Although the hill is a part of designated open access land it is also immersed in conifer plantation.  However, the summit of the hill is easily reached via a wide path now used by trail riders that follows the summit ridge in a north-east to south-west direction, and this can be accessed from a forest track to the north-east of the summit.

The survey with the Trimble GeoXH 6000 resulted in a summit height of 449.3m for Fuches and 450.0m for Allt y Derw, confirming Allt y Derw as higher and therefore the connecting bwlch between each hill is the critical bwlch for the lower hill; Fuches, and this was surveyed as being 419.1m in height, with these values giving Fuches 30.2m of drop, which is sufficient for its reinstatement to Pedwar status.

 

The full details for the two hills are:

Cardinal Hill:  Pumlumon Fawr

Name:  Fuches

OS 1:50,000 map:  135, 136

Summit Height:  449.3m (converted to OSGM15)

Summit Grid Reference:  SN 86623 83656

Bwlch Height:  419.1m (converted to OSGM15)

Bwlch Grid Reference:  SN 86997 83837  

  

Drop:  30.2m

Cardinal Hill:  Pumlumon Fawr

Name:  Allt y Derw

OS 1:50,000 map:  135, 136

Summit Height:  450.0m (converted to OSGM15)

Summit Grid Reference:  SN 87314 83429

Bwlch Height:  375.6m (LIDAR)

Bwlch Grid Reference:  SN 86411 83855 (LIDAR)

Drop:  74.4m (Trimble summit and LIDAR bwlch)

 

The Trimble GeoXH 6000 set-up position at the summit of Fuches

For the additions, reclassifications and deletions to Y Pedwarau reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Our thanks to Chris Crocker for suggesting that the data produced by LIDAR be re-evaluated for this hill

For details relating to the survey of Fuches

LIDAR and Trimble GeoXH 6000 analysis for Fuches (SN 866 836)

Myrddyn Phillips and Aled Williams (September 2018)