Mapping Mountains – Summit Relocations – Y Pedwarau – The 400m Hills of Wales

Garth Fawr (SO 082 059)

There has been a Summit Relocation to a hill that is listed in the Y Pedwarau – The 400m Hills of Wales, with the summit height and its position derived from Ordnance Survey Open Data hosted as an interactive map on the WalkLakes website.

Garth Fawr (SO 082 059).  Photo: Rob Woodall

The criteria for the list that this summit relocation applies to are:

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, the list is co-authored by Myrddyn Phillips and Aled Williams and is published on Mapping Mountains in Google Doc format.

The name the hill is listed by is Garth Fawr and it is a relatively recent man-made construction and is the result of waste spoil from the Ffos-y-fran opencast mine that is now considered solid and stable.  Therefore, it does not possess any separate ring contours for the area of its summit on either the Ordnance Survey 1:50,000 Landranger or the 1:25,000 Explorer map.

Extract from the Ordnance Survey 1:25,000 Explorer map

Garth Fawr is adjoined to the Cymoedd Gwent group of hills, which are situated in the eastern part of South Wales (Region C, Sub-Region C2), and it is positioned with the A4060 road to its west and the A469 road to its east, and has the town of Merthyr Tudful towards the north-west.

When this hill was included in the list of Y Pedwarau- The 400m Hills of Wales published on Mapping Mountains, the summit position was given as the following ten figure grid reference of SO 08597 05972, based on interpolation of one of three uppermost 410m ring contours that used to appear on the OS Maps website.

Another resource now available online is the WalkLakes website which hosts an interactive map originated from the Ordnance Survey Open Data programme.  This map has many spot heights not on other publicly available maps and shows a 410m spot height on the summit area of this hill.

Extract from the WalkLakes website

The position of the 410m spot height comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to any listed hill whose summit meets the following criteria; where there are a number of potential summit positions within close proximity and the highest point is not where previously given, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist, or when the summit of the hill is in a different field compared to where previously given, or when it is positioned to a different feature such as in a conifer plantation, or when the high point of the hill is placed within a different map contour compared to its previous listed position, or when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct.

Therefore, the new summit height for this hill is 410m and is positioned at SO 08260 05940 and appears as a spot height on the interactive map hosted on the WalkLakes website which is produced from the Ordnance Survey Open Data programme, this position is not given a spot height on contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps and is approximately 350 metres westward from where the previously listed summit is positioned.

ills of Wales, and are reproduced below@

The full details for the hill are:

Group:  Cymoedd Gwent

Name:  Garth Fawr

OS 1:50,000 map:  160

Summit Height:  410m (spot height)

Summit Grid Reference (new position):  SO 08260 05940 (spot height) 

 

Bwlch Height:  c 375m (interpolation)

Bwlch Grid Reference:  SO 08676 06119 (interpolation)

Drop:  c 35m (spot height summit and interpolated bwlch)

Aled Williams and Myrddyn Phillips (April 2020)

Mapping Mountains – Hill Reclassifications – Y Pedwarau

Garth Fawr (SO 082 059) – Pedwar addition

There has been an addition to the listing of Y Pedwarau due to detail on OS Maps, which is the recent replacement for OS Get-a-map.  The Y Pedwarau is the title for the list of 400m hills of Wales and takes in all Welsh hills at and above 400m and below 500m in height that have a minimum 30m of drop, the list is a joint compilation between Myrddyn Phillips and Aled Williams and it commenced publication on Mapping Mountains on the 30.01.17.

The name of the hill is Garth Fawr and prior to analysis of contours on the OS Maps website this hill was not listed as it is a relatively recent man-made construction and is the result of waste spoil from the Ffos-y-fran opencast mine that is now considered solid and stable, therefore it does not possess any separate ring contours for the area of its summit on either the Ordnance Survey 1:50,000 Landranger or the 1:25,000 Explorer map.

Garth Fawr is situated in the Y Cymoedd – dwyreiniol range of hills and is placed in the Region of South Wales (Region C, Sub-Region C2).  The hill is positioned between the towns of Merthyr Tudful (Merthyr Tydfil) to its north-west and Rhymni (Rhymney) to its north-east and has the A 465 Heads of the Valleys Road to its north and the A 4060 road to its west.

As the summit of this hill is not a part of designated open access land permission to visit should be sought, for those wishing to do so a minor road to the south would give access to the hill.

Garth Fawr had little natural prominence and is a southerly spur of Twyn y Waun, but due to mining activity its height has increased with the 5m contour intervals on OS Maps giving it three separate uppermost 410m ring contours and a bwlch height of c 376m based on contouring between 375m – 380m, whilst LIDAR analysis conducted by Aled Williams gives the summit height as 388.0m at SO 08521 05968 and the height of the bwlch as 374.8m at SO 08618 06004.  It is apparent that the mine spoil was deposited after the measurement of LIDAR data was taken.  Therefore, as the hill is considered solid and stable these values are sufficient for it to be listed as a Pedwar with c 35m of drop.

The full details for the hill are:

Cardinal Hill:  Twyn y Waun

 

Summit Height:  410m

Name:  Garth Fawr

OS 1:50,000 map:  160

Summit Grid Reference:  SO 082 059

Drop:  c 35m

For the additions, deletions and reclassifications to the Y Pedwarau reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Garth Fawr (SO 082 059) is now classified as a Pedwar.  Photo: Rob Woodall

Myrddyn Phillips and Aled Williams (January 2018)

Y Pedwarau – Two new Pedwar hills and re-classification of an existing Pedwar to Dual Summit status

The Pedwar listing has been updated with the addition of two new Pedwar hills and the re-classification of an existing Pedwar to Dual Summit status, all of these hills are in close proximity of one another and situated to the east of Merthyr Tudful in south Wales.

Dual Summit:  Twyn y Waun    476.0m (artificial) at SO 08209 07041 / 450.6m (natural) at SO 08442 07378

Firstly, a note on the term ‘Dual Summit’.

A hill classified as a Dual Summit is defined as one which has an extant natural summit coupled with that of a higher artificial summit, which can be described as being stable in character.  In the main, these recent man-made constructions are the result of quarrying activities producing spoil tips and to put a spin on the term ‘Dual Summit’, the natural and artificial summits of such hills could be thought of as duelling with each other for the merit of summit status, which well describes the polarising affect that such instances can have on the hill bagger, with some baggers preferring to ignore the artificial summit in favour of the natural high point and vice versa.  For those bagging Dual Summit hills, a visit to either the natural high point or the elevated man-made high point is sufficient to claim an ascent of the hill.

These recent man-made constructions are treated differently to ancient man-made constructions such as hill forts and tumuli, as if the latter are deemed stable and of an earthen character their age dictates that they can be viewed as being permanent in nature and are now effectively a part of the hill.  The concept of a ‘dual summit’ is a new one, having been devised by the authors of the Y Pedwarau listing in response to the circumstances of the following Pedwar hill.

Twyn y Waun is now considered a Dual Summit hill with its remaining natural high point positioned at SO 08442 07378 and listed with a height of 450.6m derived from a Trimble GeoXH 6000 survey, whilst the man-made construction which dominates this hill has its summit positioned at SO 08209 07041 and has a height of 476.0m.  The remains of the natural summit of this hill still exists and consists of undistinguished grazing pasture, it is now overshadowed by a man-made construction consisting of waste spoil from the Ffos-y-fran opencast mine.  The man-made construction is considered stable and can be easily climbed and consists of grassed side slopes and in the main solid waste spoil on the summit area which is interspersed with patches of grass. 

The 450.6m natural summit of Twyn y Waun is now overshadowed by its 476.0m artificial Dual Summit

The elevated man-made construction is situated on the edge of the natural summit area of Twyn y Waun and is known by mine employees as the North Tip and Overburden 1 (OB1), as it is an overburden mound from the mine extraction.  This Dual Summit hill has a prominence of 96.0m (artificial) / 70.7m (natural) and therefore if the elevated man-made construction is taken, it is a prospective new Subhump.

The 476.0m artificial Dual Summit of Twyn y Waun

As detailed above, the artificial summit of Twyn y Waun was surveyed by Myrddyn Phillips using the Trimble GeoXH 6000, with the survey having been instigated by a recent Facebook and Tump Forum post by Rob Woodall. 

New Pedwar:  Twyn y Waun    460.5m artificial summit at SO 08549 06591

This hill is a new artificial Pedwar and consists of waste spoil from the Ffos-y-fran opencast mine.  The man-made hill is considered stable and can be easily climbed and consists of grassed side slopes and in the main a grassed summit area.  This hill was created on the southern slope of Twyn y Waun and is known by mine employees as the South Tip and Overburden 2 (OB2), as it is an overburden mound from the mine extraction.  It has an artificial prominence of 41.0m.

The 460.5m artificial summit of one of the two new Pedwar hills

The survey of this hill had been on our surveying radar for some time, having been detailed in a 2015 document entitled ‘Artificial Pedwar Hills’ by Aled Williams, and was finally prompted by a recent visit communicated to Myrddyn Phillips by Rob Woodall. 

New Pedwar:  Garth Fawr    410m artificial summit at SO 082 059

This artificial hill is positioned to the south of the Ffos-y-fran mine and to the knowledge of the authors, it currently has no recorded summit visit from anyone in the hill bagging community, therefore its inclusion as a Pedwar is reliant upon detail from OS Maps (the recent replacement for OS Get-a-map) and independent visual inspection, albeit from a distance, by Rob Woodall and Myrddyn Phillips. 

The 410m artificial summit of Garth Fawr; the second of the two new Pedwar hills.  Photo:  Rob Woodall

Garth Fawr had been on our surveying radar for some time, having been detailed in a 2015 document entitled ‘Artificial Pedwar Hills’ by Aled Williams.  In early 2017, Aled Williams analysed LIDAR data for this area and recorded a summit height of 388.0m at SO 08521 05968 and a bwlch height of 374.8m at SO 08618 06004, giving a drop of 13.2m.  In late 2017, Myrddyn Phillips was contacted by Rob Woodall who reported that an unrecorded artificial hill existed on the spur known as Garth Fawr.

Garth Fawr had little natural prominence and was a southerly spur of Twyn y Waun, but due to mining activity its height has increased with OS Maps giving it three separate uppermost ring contours of 410m and a bwlch height of c 376m based on contouring between 375m – 380m, whilst LIDAR analysis conducted by Aled Williams gives the height of the bwlch as 374.8m at SO 08618 06004.  It is apparent that the mine spoil was deposited post measurement of the LIDAR data.  The northern slopes of the hill are grassed and the summit area consists of waste spoil, which is undoubtedly of a stable character.  This man-made hill is known by mine employees as Overburden 3 (OB3), as it is an overburden mound from the mine extraction.  It has an artificial prominence of c 35m.

As the mining activity in the area is ongoing, these summits could undergo a levelling process in the future.  If this does occur, the Y Pedwarau - The 400m Hills of Wales listing will be updated accordingly.

Myrddyn Phillips and Aled Williams (December 2017)