Sunday, 16 August 2015

Mapping Mountains – Significant Height Revisions – 100m Twmpau

Bryn y Beili (SJ 235 643)

There has been a Significant Height Revision initiated by a survey with the Trimble GeoXH 6000 to the listing of the 100m Twmpau (thirty welsh metre prominences and upward), with these details being retrospective as the survey that resulted in this height revision was conducted on 8th April 2014.  With the criteria for 100m Twmpau status being all Welsh hills at or above 100m and below 200m in height that have a minimum 30m of drop.

The name of the hill is Bryn y Beili (Bailey Hill in English) and it is situated in the Bryniau Clwyd range of hills and is positioned in the town centre of Yr Wyddgrug (Mold), which is situated in north-east Wales.  The survey was conducted in the company of Mark Trengove over two days, three weeks apart, and it was Mark who proposed that this hill was a candidate for becoming a new P30, his inclination proved correct.  With the first survey concentrating on the bwlch and which resulted in an unfortunate incident when the Trimble wrestled with a car and was run over, whilst the second survey concentrated on the summit of the hill.

The hill can be accessed from the top of the High Street in Yr Wyddgrug (Mold), although the hill is prominent within the town it is almost hidden from view as it rises behind the former Pendref Chapel and is surrounded by a high wall, trees and shrubs.

The summit height of Bryn y Beili has been increased from its current Ordnance Survey map height, as prior to the survey with the Trimble GeoXH 6000 the hill was not listed as it only had an uppermost ring contour of 130m on Ordnance Survey 1:25,000 Explorer maps, with a 135m spot height appearing on lower ground in the centre of a bowling rink on the Ordnance Survey enlarged mapping hosted on the Geograph website.  The hill's new summit height is 143.0m (converted to OSGM15) which is 8.0m higher than the 135m spot height.

The full details for the hill are:

Cardinal Hill:  Moel y Gamelin

Summit Height (New Height):  143.0m (converted to OSGM15)

Name:  Bryn y Beili

OS 1:50,000 map:  117

Summit Grid Reference:  SJ 23544 64367
Drop:  31.5m (converted to OSGM15)

Bryn y Beili, a new P30 and a hill whose height has been significantly revised

Myrddyn Phillips (August 2015)

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