Mapping Mountains – Hill Reclassifications – 100m Twmpau

White Park (SN 158 091) – 100m Sub-Twmpau reclassified to 100m Twmpau

There has been confirmation of a reclassification to the 100m Twmpau due to LIDAR analysis conducted by Myrddyn Phillips, with the criteria for this list being:

100m Twmpau - Welsh hills at or above 100m and below 200m in height with 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 100m and below 200m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

When the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website this hill appeared in the accompanying Hills to be surveyed sub list as it did not meet the criteria then used for the main P30 list; however this sub list has now been standardised and interpolated heights also included in the main P30 and the accompanying sub list.

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

When this list was standardised and interpolated heights also included this hill was listed with an estimated c 29m of drop, based on the 137m height given to a triangulation pillar on the summit area and an estimated bwlch height of c 108m based on interpolation of 5m bwlch contouring between 105m – 110m on the Ordnance Survey 1:25,000 Explorer map.  The drop value was re-assessed prior to LIDAR analysis and a tentative estimate of c 30m then given.

The name of the bounded land where the summit of this hill is situated is White Park, and this was derived from the Tithe map.  The hill is adjoined to the Brandy Hill group of hills, which are situated in the south-western part of Mid and West Wales (Region B, Sub-Region B4), and is positioned between the coast to its south and the A 47 road to its north, and has the small community of Ludchurch to its north-west.

If wanting to visit the hill permission to do so should be sought as it is not a part of designated open access land and has no rights of way on it, although a permissive path does cross the hill to the south of its summit.

The confirmation of the addition of White Park to 100m Twmpau status is due to LIDAR analysis conducted by Myrddyn Phillips.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

LIDAR image of the bwlch of White Park

LIDAR image of the summit of White Park

The 2m DTM LIDAR analysis gives the hill the following details:

Name:  White Park

Summit Height:  138.1m

Summit Grid Reference:  SN 15867 09111

Bwlch Height:  107.1m

Bwlch Grid Reference:  SN 15723 09669

Drop:  31.0m

Therefore, the 138.1m LIDAR analysis for the summit position at SN 15867 09111 and the 107.1m LIDAR analysis for the bwlch position at SN 15723 09669 gives this hill 31.0m of drop, which confirms its addition to 100m Twmpau status.

LIDAR image of White Park

The full details for the hill are:

Group:  Brandy Hill

Name:  White Park

OS 1:50,000 map:  158

Summit Height:  138.1m (LIDAR)

Summit Grid Reference:  SN 15867 09111 (LIDAR)

Bwlch Height:  107.1m (LIDAR)

Bwlch Grid Reference:  SN 15723 09669 (LIDAR)

Drop:  31.0m (LIDAR)

Myrddyn Phillips (September 2018)