Hill Lists – Cymru / Wales – 200m Twmpau updates – Penlle’ rcastell

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 Twenty Seventh Group is Penlle’ rcastell.

Penlle’ rcastell

 

North and then east from SS 620 907 following the Clyne River to bwlch at SS 595 939 and the Gors Fawr Brook to SS 592 967, continuing north of the Afon Llan to the sea at SS 560 979, continuing east of the Afon Llwchwr (River Loughor) to SN 622 105, continuing south of the Afon Aman to SN 686 133, continuing west of the Garnant to bwlch at SN 698 094 and the Upper Clydach River to SN 723 036, continuing west of the Afon Tawe to the sea at SS 666 917.  Bordering with the Gŵyr and Mynydd Sylen to the west, Y Mynydd Du to the north, Bryniau Cymoedd to the east and the sea to the south.     

Sub-Twmpau - 200m updates

Pt. 299m    299m    SN 696 058

This hill is a new entry in to the Welsh 200m P30 Sub-List, however its entry is contentious as Ordnance Survey mapping suggests this hill exists due to spoil heaps from old mining.  To include a hill in a list because its existence is due to man’s recent incursion is difficult, but as current Ordnance Survey maps give this hill continuous contour lines it suggests that the hill is permanent in nature and as it exists it would be difficult to not include it.  Subjectivity would also have to be taken in to account as to be considered permanent in nature the hill would ideally need to be landscaped and not comprise just spoil waste.  The Ordnance Survey enlarged Geograph map gives this hill a 299m summit spot height, and bwlch contouring is between c 270m – c 280m and the bwlch has been estimated as being c 275m high, these values give the hill c 24m of drop.

Next update due on the 20^th October 2014