Friday, 18 March 2016

Mapping Mountains – Hill Reclassifications – Y Pedwarau


Drysgol (SN 946 744) - Pedwar reclassified to 400m Sub-Pedwar

There has been another reclassification of a Pedwar to a 400m Sub-Pedwar by surveying with the Trimble GeoXH 6000.  The hill was listed as a Pedwar as it has a 484m spot height at the summit on Ordnance Survey maps and bwlch contouring between 450m – 460m, with the area of the bwlch having been surveyed using a basic levelling method based on the lay of land in relation to the position of a fence junction where a 457m spot height appears on Ordnance Survey 1:25,000 Explorer maps.  This basic survey gave the hill a drop of 102ft (31.1m) and although relying on the accuracy of spot heights which have a margin of uncertainty of +/- 3m, it was also judged sufficient to include the hill as a Pedwar as interpolation of bwlch contouring also gave the hill a drop of c 31m based on an estimated c 453m bwlch height.

The hill is situated in the southern part of the Pegwn Mawr range of hills with its Cardinal Hill being Garreg Lwyd, and is positioned on the eastern side of the A 470 as it makes its way from Llangurig southward to Rhaeadr Gwy (Rhayader).  The hill was surveyed on a grey and drizzly day in the company of Fergal Hingerty who had suggested meeting up to bag Pedwarau to add to his ever increasing total.

The name of the hill is Drysgol and it can be accessed from a track to its west that leaves the A 470 or from a track to its north-east that leaves a minor lane in the Nant Tawelan valley, another approach to the hill can be made from its south-east following the course of the Marcheini Fawr stream.

This now brings the overall total for the Y Pedwarau to 447 hills with five additions, and five reclassifications to 400m Sub-Pedwar status since publication of the list by Europeaklist in May 2013.  The hill will be taken out of the main list and added to the 400m Sub-Pedwar list in forthcoming publications.  The list of Pedwar hills is available from the Haroldstreet website.


The full details for the hill are:

Cardinal Hill:  Garreg Lwyd

Summit Height:  483.6m (converted to OSGM15)

Name:  Drysgol

OS 1:50,000 map:  136, 147

Summit Grid Reference:  SN 94630 74415

Drop:  29.2m (converted to OSGM15)


The list of additions and reclassifications from the Pedwar list since the 1st edition of Y Pedwarau was published by Europeaklist are as follows:



PEDWAR ADDITIONS








PEDWAR RECLASSIFICATIONS








Drysgol (SN 946 744) now reclassified to a 400m Sub-Pedwar

For details on the survey that reclassified this hill from Pedwar to 400m Sub-Pedwar status please click {here}

Myrddyn Phillips and Aled Williams (March 2016)




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