Wednesday, 11 May 2016

Mapping Mountains – Hill Reclassifications – 300m Twmpau

Moel y Gôd (SJ 072 168) - 300m Twmpau addition 

There has been a new addition to the 300m Twmpau (thirty welsh metre prominences and upward) hill list with its confirmation as a P30 instigated by a survey with the Trimble.   The hill is situated between Llanwddyn to its west, Dolanog to its south, Llanfyllin to its east and Pen-y-bont-fawr to its north, and is positioned in the central part of the Y Berwyn.

The hill is named Moel y Gôd and the first time it ever appeared in a hill list was in 2003 when the original Welsh P30 hills under 500m in height were published on Geoff Crowder’s website.  It was then listed in the Sub-List which was named ‘Hills to Survey’.  The reason for this was that Moel y Gôd was only given a 308m summit spot height on current maps, and meant that its qualification to the main P30 list was dependent upon bwlch contour interpolation.  As the use of interpolation did not form part of this list the hill was listed in the ‘Hills to Survey’ Sub-List.   When this list was first published on Geoff’s website it did not include a drop value for each hill, although the qualification for the main list and the Sub-List was based on drop, these values were added to the list at a later date.

When these drop values were added I also decided to include hills in the Main P30 Twmpau list through interpolation of map contours, although some of these details were passed onto Geoff, the great majority were not.  When these figures were added to the list I gave Moel y Gôd c 35m of drop and promoted it into the ranks of P30 hills.  This drop value was estimated from its 308m summit spot height and an estimated bwlch height of c 273m based on the 1:25,000 map bwlch contouring between 270m – 280m.  Even though the hill had been promoted in my list the details were never made public, so it was now time to have it Trimbled and to confirm its status via the Mapping Mountains site.

The hill can be accessed from where a public footpath contours round its northern flank; however the summit is not situated on open access land so permission to visit should be sought.  There is sufficient parking for one or two vehicles near the intersection between the B 4393 and the B 4395 which is only a short distance from the gate giving access on to the footpath.

The survey with the Trimble GeoXH 6000 resulted in a 307.6m (converted to OSGM15) summit height and a 270.6m (converted to OSGM15) bwlch height; these values give this hill 37.0m of drop and confirm its status as a P30 Twmpau.

The full details for the hill are:

Cardinal Hill:  Rhialgwm

Summit Height:  307.6m (converted to OSGM15)

Name:  Moel y Gôd

OS 1:50,000 map:  125

Summit Grid Reference:  SJ 07248 16808

Drop:  37.0m (converted to OSGM15)

Moel y Gôd (SJ 07248 16808) now confirmed as a 300m Twmpau

For details on the survey that confirmed this hill as a 300m Twmpau status please click {here}

Myrddyn Phillips (May 2016)

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