Monday, 3 April 2017

Mapping Mountains – Hill Reclassifications – Yr Uchafion


Moel Bowydd (SH 712 470) - Uchaf addition

There has been a new addition to the ranks of Yr Uchafion instigated from analysis of LIDAR data by Aled Williams and subsequently confirmed via a survey with the Trimble GeoXH 6000.  Yr Uchafion is the draft title for a list of the Welsh 500m P15s that takes in all hills in Wales at or above 500m that have a minimum drop of 15m, the list is a joint compilation with Aled Williams, with the details relating to this list being published on the Mapping Mountains site in November 2015.

This hill is given an uppermost 490m ring contour with no spot height on current Ordnance Survey maps and has bwlch contouring between 480m – 490m, and prior to the analysis of LIDAR data the hill was not classified.

The hill is adjoined to the Arennig group of hills with its Cardinal Hill being Manod Mawr (SH 724 446) and is placed in the Region of North Wales (Region A, Sub-Region A3), and is situated with the town of Blaenau Ffestiniog to the south-west and is positioned above the Afon Bowydd which is to its south and which emanates from Llyn Bowydd which is to the east of the hill.

The hill can be accessed via public footpaths from its west, east and south, with Blaenau Ffestiniog being a good starting point for an ascent; an alternate and longer ascent can start from above Llan Ffestiniog using a track beside the course of the Afon Teigl.  However, the summit of this hill is not on open access land, therefore permission should be sought to visit, but as the summit is relatively close to a public footpath and with open access land to its immediate north, common sense should prevail and if wanting to visit the summit of the hill there is likely to be no objection to doing so.

The name of the hill is Moel Bowydd and its addition to Uchaf status is due to analysis of LIDAR data by Aled Williams.  LIDAR (Light Detection & Ranging) is highly accurate height data that is now freely available for much of England and Wales.

Aled’s analysis of LIDAR data gives the hill the following details:


Moel Bowydd

Summit Height:  500.6m

Summit Grid Reference:  SH 71276 47053

Bwlch Height:  c 485m

Bwlch Grid Reference:  SH 71586 47206

Drop:  c 16m


Although the area of the bwlch is not covered by LIDAR data, 1m contouring shows that the bwlch is lower than 485m, which gives this hill sufficient drop to qualify as an Uchaf.  Therefore, the 500.6m LIDAR data produced for the summit position at SH 71276 47053 and with 1m bwlch contouring showing that the height of the bwlch is below 485m, giving this give a drop of more than 15m, with the details from the Trimble GeoXH 6000 survey being 500.5m (converted to OSGM15) summit at SH 71272 47051 and 482.4m (converted to OSGM15) bwlch at SH 71603 47208, giving this hill 18.1m of drop


The full details for the hill are:

Cardinal Hill:  Manod Mawr

Summit Height:  500.5m (converted to OSGM15, Trimble data)

Name:  Moel Bowydd

OS 1:50,000 map:  115

Summit Grid Reference:  SH 71272 47051
   
Drop:  18.1m (converted to OSGM15, Trimble data)


This now brings the overall total for Yr Uchafion / The Welsh 500m P15s to 631 hills with the overall total for the 500m Sub-Uchaf category remaining at 25.

The additions, reclassifications and deletions to Yr Uchafion / The Welsh 500m P15s reported on Mapping Mountains are ills of wales as follows:



UCHAF ADDITIONS







Moel Bowydd (Trimble data) (SH 71272 47051) added as an Uchaf with 18.1m of drop





500m SUB UCHAF RECLASSIFICATIONS TO UCHAF






UCHAF RECLASSIFICATIONS TO 500m SUB-UCHAF










UCHAF RECLASSIFICATIONS TO 490m SUB-UCHAF






UCHAF DELETIONS





Moel Bowydd (SH 712 470) is now classified as an Uchaf


Myrddyn Phillips and Aled Williams (April 2017)





No comments: