Monday 17 November 2014

Hill Lists – Cymru / Wales – 200m Twmpau updates – Bryniau Cymoedd



The first list to the Welsh 200m P30 hills was published on Geoff Crowder’s website v-g.me in 2000; this list preceded the list of TuMPs by nine years, the list proved a very useful resource for the TuMP compilation for this category of hill.

The Welsh 200m P30 list documents all hills in Wales that are at or above 200m in height and are below 300m in height, to qualify for the main list each hill requires a minimum of 30m of prominence.


The hills listed below are updates to the Welsh 200m P30 list originally published on Geoff Crowder's website.  To see the original list click {here}


The original published list had a Sub-List which was entitled ‘Hills to Survey’.  This list consisted of all hills in Wales in the stipulated height band that have a minimum of 20m of prominence, but do not meet the minimum 30m of prominence to enter the main list, according to Ordnance Survey map spot heights and contours.  Nowadays the standard Sub-List takes in all hills that have a minimum of 20m of prominence.  However, the Hills to Survey Sub-List discounted hills whose map spot heights gave a drop value of less than 30m, but more than 20m.  By doing so, the only hills that were Sub-Listed were those that map values dictated stood a chance of entering the main list, for example; if a hill had a summit spot height of 250m and a bwlch spot height of 221m, it was not listed in the Hills to Survey Sub-List as with 29m of drop I thought it did not stand a chance of main list qualification. 

When compiling the Sub-List I was measuring many hills for P30 status using a basic levelling technique, please click {here} for more information concerning this.  I now know that Ordnance Survey spot heights have a standard margin of uncertainty of + / - 3m associated with their accuracy.  Therefore many hills that were not listed in the original Sub-List may have sufficient drop to enter the main list.  Because of this the Sub-List has been altered to include all hills that have a minimum of 20m of drop but are not known to attain the minimum 30m of drop to enter the main list.

The hills listed below are those major amendments to the original Welsh 200m P30 list as it appears on Geoff’s website.  There are many hills that have been promoted from the Hills to Survey Sub-List to the main list, whilst there are many additions to the Sub-List now that it has been standardised to include all 20m minimum but below 30m drop hills.

When the 200m P30 list was first published it was the first to this category of hills and in some way it and its other 100m height band lists paved the way for Clem’s data that later appeared on the RHB file database and then for the TuMPs listing by Mark Jackson.

As well as the first P30 list to this height band the list is now the first to include a comprehensive Sub-List.

TuMP baggers beware; as the main list also includes P30’s not listed by Mark Jackson, so if you want to visit all P30’s you’ll have to include some non TuMPs to do so.

The list will be updated on a weekly basis and will be done so through each Group category, starting from the north and working south.  The Thirty Second and last Group is Bryniau Cymoedd.



Bryniau Cymoedd

North from the sea at ST 194 721 following the Afon Elรกi (Ely River) to ST 030 812, the Nant Melyn towards bwlch at ST 007 830, the Ewenni Fach to SS 954 799, the Afon Ewenni (Ewenny River) to SS 878 767 and the Afon Ogwr (Ogmore River) to the sea at SS 855 757, continuing east from the sea at SS 666 917 following the Afon Tawe to SN 723 036, the Upper Clydach River to bwlch at SN 698 094 and the Garnant to SN 686 133, continuing south of the Afon Aman (River Amman) to bwlch at SN 739 135, the Afon Twrch to SN 771 083, the Afon Tawe to SN 834 127, the Nant Llech to bwlch at SN 844 107, the Afon Pyrddin to SN 898 091, the Afon Nedd (River Neath) to SN 902 074 and the Afon Mellte to SN 910 079, continuing south of the Sychryd and Camnant to bwlch at SN 942 062 and the Afon Cynon to SN 988 046, and the Nant y Gwyddel to bwlch at SO 005 073 and following stream to SO 030 076, the Taf Fawr to SO 046 062, the Nant Moriais to bwlch at SO 082 086, and bwlch at SO 119 101, and bwlch at SO 147 115, and bwlch at SO 174 115, and bwlch at SO 192 115, and the River Clydach to SO 242 154, and the Afon Wysg (River Usk) to the sea at ST 323 813.  Bordering with Y Mynydd Du, Fforest Fawr, Bannau Brycheiniog and Y Mynyddoedd Duon to the north, Coed Gwent to the east, the sea and Bro Morgannwg to the south and Penlle’rcastell to the west. 
             


Twmpau - 200m updates

Pt. 245m    245m    SN 721 059

This hill was originally listed under the name of Cefn Llan, which had been taken from buildings to the west of the summit, as the blog author does not know an appropriate name for the hill it is reverting to the Pt. notation.  The summit height is taken from a 245m trig pillar, and the bwlch height is taken from a 214m spot height that appears on the Ordnance Survey enlarged Geograph map.  These values give this hill 31m of drop and therefore the hill is promoted from the Sub-List.



Sub-Twmpau - 200m updates

Pt. 209m    209m    SN 714 013

The Pt notation is being used for the name of this hill as it seems two names that appear near to this hill’s summit on the map; Graig Ola and Craig-y-perchyll may be applicable to buildings and not the hill.  This is a another hill that benefits from the Ordnance Survey enlarged Geograph map, as the bwlch has a 184m spot height on it on this map, and with a summit spot height of 209m, this hill enters the Sub-List with 25m of drop.



Mynydd Portref    277m    SS 993 856

This hill has a summit spot height of 277m and bwlch contouring between c 250m – c 255m, with the height of the bwlch estimated as c 252m, giving this hill c 25m of drop.



Pt. c 241m    c 241m    ST 166 968

The summit of this hill is situated in the town of Coed-duon (Blackwood) and its height has been estimated as c 241m from an uppermost contour of c 240m.  The area of its bwlch has a 216m spot height on it that appears on the Ordnance Survey enlarged Geograph map, these values give this hill c 25m of drop.



Craig y Merchant    213m    ST 252 910

With a summit spot height of 213m and a bwlch spot height of 191m, this hill enters the Sub-List with a drop of 22m.  The bwlch spot height comes from the Ordnance Survey 1:50,000 map, although the actual spot is hard to distinguish where it is placed.



Coedyprior Common    297m    SO 293 103

The name of Coedyprior Common appears on the Ordnance Survey enlarged Geograph map and has been chosen as this hill’s designated name, whilst the Ordnance Survey 1:25,000 and 1:50,000 scale maps have the name of the hill as Coed-y-Prior Field.  The hill enters the Sub-List as it has 21m of drop based on a summit spot height of 297m and a bwlch spot height of 276m.



Parc Penallta    235m    ST 136 953

Parc Penallta has a large landscaped figure of a pit pony at its summit, a must visit Sub-Hill!  The summit has a 235m spot height that appears on the Ordnance Survey enlarged Geograph map, and the bwlch height has been estimated as c 214m high based on bwlch contouring between c 210m – c 220m, these values give this hill c 21m of drop.



Pt. 223m    223m    SN 800 079

This hill’s name is listed under the Pt notation as the blog author does not know an appropriate name for it.  The area of the bwlch has three different spot heights on it; 208m at SN 803 084, 203m at SN 802 082 and 202m at SN 803 086, the latter two appearing on the Ordnance Survey enlarged Geograph map.  The 202m spot height has been taken as the height of the bwlch, which gives this hill 21m of drop.



Twynau Gwynion    229m    ST 152 834

The Ordnance Survey enlarged Geograph map gives a 208m spot height on the area of this hill’s bwlch at ST 15422 84045, whilst the 1:25,000 map has a 209m spot height placed at ST 15445 84070, as the latter is more centralised on the valley to valley traverse this hill is included in the Sub-List with 20m of drop.



Coed Mawr    214m    ST 246 887

With a summit spot height of 214m and a bwlch spot height placed at ST 237 891 of 194m, this hill enters the Sub-List with 20m of drop.



Pt. 275m    275m    ST 192 978

Another hill that follows the Pt notation as the blog author does not know a suitable name for it.  The summit area has a 274m trig pillar on it with Ordnance Survey 1:25,000 and 1:50,000 scale maps giving a separate spot height of 275m near to the trig, the bwlch contouring is between c 250m – c 260m and the height of the bwlch has been estimated as c 255m, giving this hill c 20m of drop.



This now completes the updates to the 200m Twmpau List

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