Mapping Mountains – Hill Reclassifications – Y Trechol – The Dominant Hills of Wales

Moel y Gadair (SH 521 391) - Lesser Dominant deletion

This hill has subsequently been reinstated to Lesser Dominant status due to LIDAR analysis indicating this hill is a natural P30, with the raised road passing over the bwlch considered a relatively recent man-made construct; therefore it is excluded from the height of the bwlch. 

There has been a deletion from the listing of Y Trechol – The Dominant Hills of Wales due to a survey with the Trimble GeoXH 6000 and subsequent LIDAR analysis which has resulted in the hill being taken out of the Lesser Welsh Dominant list and subjected to a life of rather pitiful non dominance.

The hill is in positioned in the Moel Hebog group and is situated on the south-western outskirts of the small community of Pentrefelin, which is positioned between the towns of Porthmadog to its east and Cricieth to its south-west.

The Trimble GeoXH 6000 survey that resulted in this hill’s deletion was conducted over two days, with the hill’s summit being surveyed on the 15^th June 2015 in warm and sunny conditions, and the bwlch being surveyed on the 23^rd February 2016 on a beautiful winter’s day, with subsequent LIDAR analysis confirming the status of this hill.

If wanting to visit the hill it can be accessed from a public footpath to its south-west, but as its summit is not on open access land permission to visit its high point should be sought.

The name of the hill is Moel y Gadair and it had been listed with 45.05% dominance and a drop value of c 30m, with the latter figure the minimum required for qualification to the Dominant list.  These figures were based on a summit survey of 66.7m and an interpolated bwlch height of c 37m based on bwlch contouring between 35m – 40m.  During the 15^th June 2015 survey the contours at the bwlch were misinterpreted resulting in the second bwlch survey which was conducted on the 23^rd February 2016 and the subsequent LIDAR analysis resulting in a bwlch height of 36.8m.

Therefore, the deletion of this hill from Lesser Dominant status is due to a 66.7m summit height and a 36.8m bwlch height, with these values giving this hill 29.9m of drop which is insufficient for qualification to the Dominant list.

The full details for the hill are:

Group:  Moel Hebog

Name:  Moel y Gadair

Dominance:  N/A

OS 1:50,000 map:  124

Summit Grid Reference:  SH 52165 39135

Summit Height:  66.7m (converted to OSGM15)

Drop Summit to Bwlch:  29.9m

Drop Bwlch to ODN:  36.8m (LIDAR)  

The final nail in the coffin - the Trimble set-up position at the bwlch of Moel y Gadair (SH 521 391)  which resulted in this hill's deletion from the Lesser Dominant list

For details on the summit survey and the bwlch survey that resulted in this hill being deleted from Lesser Dominant status.

My thanks to Aled Williams for his initial LIDAR analysis

Myrddyn Phillips (February 2016)