Monday 23 June 2014

Hill Lists – Cymru / Wales – 200m twmpau updates – Carnedd Wen



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 eleventh Group is Carnedd Wen.



Carnedd Wen 
North and west of the Afon Hafren (River Severn) and the border with England at SJ 328 158 to SO 027 916, continuing north of the Afon Carno to bwlch at SN 930 998, and north of the Afon Laen to SH 896 025, continuing east of the Afon Rhiwsaeson and the Nant Carfan to bwlch at SH 891 083, and continuing east of the Afon Tafalog to SH 890 121, continuing south of the Afon Dugoed to Bwlch y Fedwen at SH 934 138 and the Afon Banwy to SJ 143 114, continuing south of the Afon Efyrnwy (River Vyrnwy) to the border with England at SJ 268 205.  Bordering with Y Berwyn to the north, Mynydd y Cemaes to the west, Pumlumon, Pegwn Mawr and Beacon Hill to the south and Cefn Digoll, Breiddin and the English border to the east.    



Twmpau - 200m updates

Bwlch Clump    262m    SJ 170 108

This is a new twin top with an already existing Welsh 200 P30 hill.  The name of Bwlch Clump is taken from the Ordnance Survey enlarged Geograph map, as indeed is the 262m summit height.  The existing P30 that this is twinned with is Pt. 262m (originally listed by the part invented name of Pen y Bryn Wood) which is positioned at SJ 173 109.


Stingwern Wood    c 258m    SJ 145 000

This is a summit relocation from Pt. 251m (originally listed by the part invented name of Pen Cefnblewog) which is positioned at SO 154 996.  The original listing prioritised the 251m spot height position on the OS 1:25,000 Explorer map in preference to a c 250m contour ring, even if the contour ring at SJ 145 000 was large in comparison to where the spot height contour ring appears at SO 154 996.  The new summit position has an uppermost c 255m contour ring on the OS enlarged Geograph map, to complicate matters there is another separate c 255m contour ring at SO 147 994 at Upper House Wood, the former is prioritised as the c 255m contour ring is larger.  No absolute height has been found on any Ordnance Survey map for the new summit location.


Boncyn y Beddau    253m    SO 107 981

This is a promotion from the Sub-List and a new p30 that doesn’t appear in Mark Jackson’s list of the TuMPs.  The hill was originally listed as Bryn y Brain, a part invented name from the wood to the south of the summit.  The critical area for this hill’s inclusion to the P30 ranks is its bwlch.  The contouring on most current Ordnance Survey maps is between c 220m – c 230m.  However, the enlarged Geograph map has 5m contour intervals and narrows the margin of interpolation down to c 220m – c 225m.  This latter map has the hill to hill contours very close together and centred on a road near to a junction with a track at SO 10782 98745, implying a c 224m bwlch, with c 29m of drop.  This is beside a house named as Bryn View on old maps.  The opposing valley to valley contours are relatively far apart, with a 222m spot height appearing at SO 10965 98831 on the enlarged Geograph map.  This spot height is near to a pool that does not appear on any other OS map, this pool is situated where an old clay pit is positioned on old maps.  The 5m interval Geograph hill to hill contours seem to dismiss this 222m spot height as being positioned too low for the critical bwlch.  But all other OS maps (including the Seventh Series, New Popular and Historical 1:25,000) indicate the critical bwlch to be centred near to where the 222m spot height appears on the current enlarged Geograph map.  Driving around these lanes in a Google Car also substantiates the position of the 222m spot height as a more favourable critical bwlch position when compared to the road immediately beside the house named as Bryn View on old maps.  Google Cars are not the be all and end all for critical bwlch positions, but they are good fun!  Hedges and tree growth in this area are quite high but a view can be found that follows the valley to valley traverse from beside Bryn View past another house toward the old clay pit.  This view suggests that the ground is still rising from the 5m contour interval centred position on the road at SO 10782 98745 to the position where the 222m spot height appears on the map.  Therefore, the 222m spot height is being taken as the position for the critical bwlch, giving this hill 31m of drop.


Pt. 249m    249m    SO 137 950

This is a promotion from the Sub-List.  This hill was originally listed by the name of Bryn-rorin, as this is the name of a farm to the north-east of the summit the Pt. notation is being used.  The old 241m height of the hill was taken from the Ordnance Survey 1:50,000 Landranger map with the spot height appearing at SO 13866 95066.  With the advent of the enlarged map on the Geograph website many more spot heights are now available, including a 249m spot height at SO 13701 95036 for this hill.  The bwlch is positioned in one of two spots; 213m at SO 139 957 or c 213m at SO 144 957, giving this hill a drop of 36m / c 36m.


Pt. 238m    238m    SO 111 962 / SO 103 962

This is another promotion from the Sub-List.  This hill was originally listed as a twin summit with c 230m tops, one listed as Bryncoch and the other listed as Bryneithin.  As each name applies to a near farm the hill is now listed under the Pt. notation.  Although the names have been dispensed with the twin top status remains, as each summit is given a 238m spot height on the Ordnance Survey enlarged Geograph map.  The bwlch contouring is between c 205m – c 210c and is estimated as c 208m and centred at SO 102 964.  The 207m spot height near to this centralised position is considered too low and not at the critical bwlch.  The 238m summit and c 208m bwlch value give this hill c 30m of drop.



Sub-Twmpau - 200m updates

Pt. 289m    289m    SJ 080 032

A new hill for the Sub-List as it has a 289m summit spot height and a 261m bwlch spot height at SJ 076 032, which is on a minor road adjacent to the farm of Llawnt Isaf.  These values give this hill 28m of drop.


Pt. 299m    299m    SJ 173 073

Another new hill for the Sub-List and another hill that follows the Pt. notation as no suitable name is known for the hill by the blog author.  The hill is positioned on the Welshpool Golf Course, close to where I live.  Its immediate parent hill is the Marilyn of Y Golfa (SJ 182 070).  With a summit spot height of 299m and a bwlch spot height of 272m at SJ 174 071, this hill has 27m of drop.   


Pt. 269m    269m    SJ 061 016

A hill that is positioned just to the north of a farm named Llwyncopa.  It has a 243m bwlch spot height at SJ 065 016 and a 269m spot height at the summit.  The latter appearing on the Ordnance Survey enlarged Geograph map.  These values give this hill 26m of drop.


Pt. 268m    268m    SH 996 069

As no appropriate name is known by the blog author for this hill, it follows the Pt. notation (yet another one – there’s a lot of research required to find appropriate names for these Welsh 200m Sub-P30 hills).  The Ordnance Survey enlarged Geograph map has a 268m spot height on the area of the summit, the bwlch contouring is between c 240m – c 250m, with the height of the critical bwlch being estimated as c 242m, giving this hill c 26m of drop.


Pt. 278m    278m    SJ 114 004

This hill that is neatly positioned between the farms of Cefngwernfa to its south-west and Bryncaemaeshir to its east.  The summit has a 278m spot height and as the Ordnance Survey enlarged map on the Geograph website has contours at 5m intervals, it narrows the bwlch height to between c 250m – c 255m, with the height estimated as c 253m.  These values give the hill c 25m of drop.


Pt. 247m    247m    SJ 186 126

This hill has a 247m spot height on the Ordnance Survey 1:50,000 and 1:25,000 map that is adjacent to a triangulation pillar that has a 245m map height.  The trig is named Cae-Bardd (Caebardd is a farm north-eastward of the summit) and is given a flush bracket height of 245.668m in the OS Trig Database.  The base of the trig will be approximately 30cm lower than the flush bracket height – 245.37m.  This height is still 1.6m lower than the 247m spot height; therefore there should be ground significantly higher on this hill when compared to the trig position.  I’ve looked on the excellent TrigpointUK.com website and there are 13 photos showing the trig, many are quite close, but those that show ground away from the trig do not show any that is higher.  However, one photo does show a bench, so for those visiting this hill you can relax and admire the view whilst contemplating where the higher ground is.  The bwlch contouring is between c 220m – c 230m and has been estimated as c 222m, giving this hill c 25m of drop to the spot height of 247m.


Pen y Garreg    219m    SO 161 960

This hill (map composition of Pen-y-gareg) has a 219m summit spot height on the Ordnance Survey enlarged Geograph map and bwlch contours between c 190m – c 195m, with an estimated bwlch height of c 194m, giving this hill c 25m of drop.


Pt. c 256m    c 256m    SO 092 962

Both the summit and bwlch height have been estimated from contour interpolation, with the Ordnance Survey enlarged Geograph map having 5m contour intervals.  The summit has an uppermost c 255m contour ring with the height estimated as c 256m, whilst the bwlch contouring is between c 230m – c 235m with an estimated bwlch height of c 232m, giving this hill c 24m of drop.


Pt. 217m    217m    SO 164 995

Another hill that benefits from the Ordnance Survey enlarged Geograph map having contour intervals at 5m.  The summit has a 217m spot height and the bwlch contours are between c 190m – c 195m with an estimated bwlch height of c 193m at SO 159 996, giving this hill c 24m of drop.


Pt. 259m    259m    SJ 104 024

With a bwlch spot height of 236m at SJ 104 028 on the Ordnance Survey enlarged Geograph map, this hill has a drop of 23m. 


Pt. 289m    289m    SJ 106 031

The hill is listed under the Pt. notation, although there is a farm named Maesprydd which is adjacent to the 289m spot height.  The area of the bwlch has a 267m spot height on the Ordnance Survey enlarged Geograph map, but it’s position is judged to be too high  on the hill to hill traverse.  Therefore the height of the bwlch is estimated to be c 266m from contouring between c 265m – c 270m, giving this hill c 23m of drop.


Pt. 247m, Moel y Garth    247m    SJ 203 097

The Ordnance Survey enlarged Geograph map has a 247m summit spot height for this hill and with an estimated bwlch height of c 224m (bwlch contouring between c 220m – c 225m) it gives this hill c 23m of drop.


Pt. 247m    247m    SJ 069 007

Another hill’s estimated drop that benefits from the Ordnance Survey enlarged Geograph map having contour intervals at 5m.  The bwlch contouring is between c 220m – c 225c and has been estimated as c 224m at SJ 067 009, giving this hill c 23m of drop.


Pt. 299m    299m    SJ 071 043

The 299m summit spot height appears next to what may be a cow shed attached to a farm named Bryngwewir.  This name may also apply to the hill, but until further enquiry can be made the name follows the Pt. notation.  The bwlch contouring is between c 275m – c 280m, with the bwlch height being estimated as c 277m, giving this hill c 22m of drop.


Pt. c 296m    c 296m    SJ 108 050

A hill whose summit and bwlch height have been estimated from contour interpolation, but as the Ordnance Survey enlarged Geograph map has contour intervals at 5m it makes the task a little easier.  The summit has an uppermost c 295m contour ring and has been estimated as c 296m, whilst the bwlch contouring is between c 270m – c 275m and has been estimated as c 274m at SJ 109 049, giving this hill c 22m of drop.


Pt. c 275m    c 275m    SO 079 960

The Ordnance Survey enlarged Geograph map has a small uppermost c 275m contour ring at the summit (estimated as c 275m high) and a bwlch spot height of 253m at SO 079 958 which gives this hill c 22m of drop.


Pt. 259m    259m    SO 087 963

The bwlch has a 238m spot height at SO 083 961 on the Ordnance Survey enlarged Geograph map, this could easily be positioned at the critical bwlch, but the valley to valley contours are closer to one another and centred on a bwlch position at SO 085 961.  Therefore the height of the bwlch has been estimated as c 237m at SO 085 961, giving this hill a drop of c 22m.


Pt. c 206m    c 206m    SJ 167 061

The summit has been estimated as c 206m from an uppermost c 205m continuous ring contour and the height of the bwlch has been estimated as c 184m, from bwlch contouring between c 180m – c 185m, giving this hill c 22m of drop.  This is another hill that follows the Pt. notation as no appropriate name is known for it by the blog author.


Pt. 268m     268m    SJ 166 120

The summit has a 268m spot height on it that appears on the 1:25,000 and Geograph map, whilst the bwlch has a 247m spot height that comes from the Ordnance Survey enlarged Geograph map, giving this hill 21m of drop.


Pt. 279m     279m    SJ 013 079

There are two possibilities for the position of this hill’s critical bwlch.  The first is at SJ 010 082, and the second is at SJ 011 084, both have contouring between c 255m – c 260m, and both have been estimated as c 258m.  With a summit height of 279m, this gives the hill c 21m of drop.


Pt. c 245m     c 245m    SJ 084 023

Contour interpolation is helped by the Ordnance Survey enlarged Geograph map having 5m contour intervals.  The summit has a small c 245m uppermost contour (estimated height of c 245m, it is quite small!) and the bwlch contouring is between c 220m – c 225m, with an estimated height of c 224m at SJ 083 026.  These values give this hill c 21m of drop.


Pt. 243m     243m    SO 159 963

Another hill that follows the Pt. notation as the blog author does not know an appropriate name for the hill.  Bwlch contouring is between c 220m – c 225m, with an estimated height of c 222m, giving this hill c 21m of drop.


Pt. 238m     238m    SO 099 969

The Ordnance Survey enlarged Geograph map has a 238m summit spot height for this hill, it also gives a 236m height to a mound south-eastward of the summit.  The bwlch contouring is between c 215m – c 220m and has been estimated as c 217m, giving this hill a drop of c 21m.


Pt. 207m     207m    SJ 041 097

The bwlch contouring for this hill is between c 185m – c 190m and has been estimated as c 186m, giving this hill c 21m of drop.



Pt. 229m     229m    SJ 193 097

The summit and bwlch are both spot heighted on the Ordnance Survey enlarged Geograph map with 229m and 209m (SJ 184 096) respectively, these values give this hill 20m of drop.  The enlarged Geograph map also spot heights another summit contender as 227m at SJ 191 095.


Pt. 214m     214m    SO 120 974

The area of the bwlch has a 194m spot height on it on the Ordnance Survey enlarged Geograph map at SO 122 975.  This value gives the hill 20m of drop.


Pt. 282m     282m    SH 997 098

This hill’s bwlch contouring is between c 260m – c 270m and has been estimated as c 262m, giving the hill c 20m of drop.  This is another example where the Pt. notation is used for the name of the hill as no appropriate name is known by the blog author.


Pt. c 252m     c 252m    SO 110 935

Although both summit and bwlch height have been estimated from contour interpolation, the hill benefits from having contour intervals at 5m on the Ordnance Survey enlarged Geograph map.  These are c 250m for the summit (estimated as c 252m) and c 230m – c 235m for the bwlch (estimated as c 232m).  These values give this hill c 20m of drop.


Pt. 249m     249m    SJ 012 092

The summit has a 249m spot height on the Ordnance Survey enlarged Geograph map, the bwlch contouring is between c 225m – c 230m and is estimated as c 229m, giving this hill c 20m of drop.


Pt. c 216m     c 216m    SO 120 987

The summit height has been estimated as c 216m from an uppermost contour of c 215m, whilst the bwlch has a 196m spot height on it on the Ordnance Survey enlarged Geograph map, giving this hill c 20m of drop.


Pt. 204m     204m    SJ 140 092

The summit height for this hill is unusual as the Ordnance Survey enlarged Geograph map has contour intervals at 5m, and has an uppermost contour of c 205m that has a 204m spot height in it, whilst the ground between the c 200m – c 205m contours has a 205m spot height in it.  I’ve opted for caution and decided to list the hill with a summit height of 204m.  By doing so it means this hill has a twin 204m top at SJ 142 089.  The bwlch contouring is between c 180m – c 185m and is estimated as c 184m.  There is a 182m spot height at SJ 142 096 on the area of the bwlch on the enlarged Geograph map; this is considered too low and not positioned at the critical bwlch.  The hill is listed with c 20m of drop.


Next update due on the 30th June 2014

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