Monday, 11 August 2014

Hill Lists – Cymru / Wales – 200m Twmpau updates – Beacon Hill



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 eighteenth Group is Beacon Hill.


Beacon Hill 

North of the River Lugg and the border with England at SO 310 650 to bwlch at SO 178 717, continuing north of the Cwm Minwood and the River Aran to SO 114 653, continuing east of the Afon Ieithon (River Ithon) to SO 087 827 and the Camnant to bwlch at SO 070 842, following stream to SO 081 859 and the Cwm-y-rhiwdre Brook to Lake Mochdre and the Mochdre Brook to SO 085 906, continuing south of the Afon Hafren (River Severn) to SJ 208 005 and the Camlad to the border with England at SO 229 993, continuing west of the border with England to SO 259 947, continuing south of the Lack Brook and the Camlad to the border with England at SO 300 922.  Bordering with Corndon, the border with England, Cefn Digoll and Carnedd Wen to the north, Pegwn Mawr to the west, Fforest Glud to the south and the border with England to the east.



Sub-Twmpau - 200m updates

Ffridd Faldwyn    248m    SO 217 969

A hill that is situated just to the north-west of Trefaldwyn (Montgomery), the bwlch contouring is between c 220m – c 225m and has been estimated as c 222m, giving this hill a drop of c 26m.


Geufron Woods    277m    SO 178 934

As the summit looks as if it is just in the wood known as Geufron Woods this name has been used, otherwise the Pt. notation would have been employed.  The 277m summit spot height comes from the Ordnance Survey enlarged Geograph map, whilst there is also a 254m spot height from this same map at SO 18305 93275 on the area of the bwlch, this has been judged as being too high.  The Ordnance Survey 1:50,000 map has a 251m height close to the bwlch, but there doesn’t seem to be a spot giving its position, therefore as the bwlch contouring is between c 250m – c 255m and estimated as c 252m, this hill is listed with c 25m of drop.


Pt. 258m    258m    SO 147 894

This hill is the old Motte and Bailey on the outskirts of Ceri (Kerry), it has a summit spot height of 258m and a bwlch spot height of 238m, the latter coming from the Ordnance Survey enlarged Geogrph map.  These values give this hill 20m of drop.



Next update due on the 18th August 2014

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