Saturday, 7 January 2017

Mapping Mountains – Hill Reclassifications – Yr Uchafion

Cwar yr Ystrad (SO 082 140) - Uchaf addition

There has been a new addition to the listing of Yr Uchafion due to analysis of LIDAR data by Aled Williams with a subsequent Trimble GeoXH 6000 surveyYr 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.  Details relating to this list were published on the Mapping Mountains site in November 2015.

The hill is situated in the Cymoedd Gwent group of hills and is placed in the Region of South Wales (C-2).  The hill is a part of the Cwar yr Ystrad quarry and this is where it takes its name from and its qualification as an Uchaf is partly due to quarrying that has taken place over past years, the hill is situated between the Pentwyn and Pontsticill Reservoirs to its west and the Talybont Reservoir to its north north-east, with the town of Merthyr Tudful to its south south-west and the small community of Trefil to its east south-east.

Contemporary Ordnance Survey 1:50,000 and 1:25,000 mapping does not give this hill any ring contours, as is the norm for areas of land that have been quarried.  The hill is now listed as an Uchaf through the quarrying activities of past years that has resulted in producing a new bwlch for the hill.

The hill can be accessed from public footpaths that approach it from a number of directions, whilst one of the most convenient routes is via the paved road north of Trefil that gives access onto the track that makes its way up to the quarry, but if wishing to ascend from this direction it should be noted that there is a barrier across the road beyond Trefil that is locked at 5.00pm and unlocked at 6.30am with online write ups stating this barrier is locked at weekends.

The name of the hill is Cwar yr Ystrad and it should be noted that this is the second new Uchaf hill to be announced recently that is listed under the same name, with the first new Uchaf hill listed as Cwar yr Ystrad being positioned at SO 08445 14278, and its inclusion as an Uchaf is due to the analysis of LIDAR data by Aled.  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:

Cwar yr Ystrad

Summit Height:  572.8m

Summit Grid Reference:  SO 08216 14087

Bwlch Height:  555.3m

Bwlch Grid Reference:  SO 07952 13652

Drop:  17.5m

The subsequent Trimble GeoXH 6000 survey produced a summit height of 572.7m and a bwlch height of 555.2m, with these values giving this hill 17.5m of drop, which is sufficient for this hill to be classified as an Uchaf.

This now revises the total in Yr Uchafion which will be updated accordingly.

The full details for the hill are:

Cardinal Hill:  Pen y Fan

Summit Height:  572.7m (converted to OSGM15)

Name:  Cwar yr Ystrad

OS 1:50,000 map:  160

Summit Grid Reference:  SO 08211 14086 
Drop:  17.5m

The summit of Cwar yr Ystrad (SO 082 140)

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


Cwar yr Ystrad (LIDAR data) (SO 082 140) added as an Uchaf with 17.5m of drop.



Myrddyn Phillips and Aled Williams (January 2017)

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