Mapping Mountains – Hill Reclassifications – The Welsh P15s

 

Tywyn Niwbwrch (SH 419 625) – Welsh P15 addition

There has been an addition to the list of The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Tywyn Niwbwrch (SH 419 625)

The criteria for the list that this addition applies to are: 

The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10^th May 2019. 

The Welsh P15s by Myrddyn Phillips

The name the hill is listed by is Tywyn Niwbwrch and it is adjoined to the Ynys Môn group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with the coast to its south-west and the A4080 road to its north-east, and has the village of Niwbwrch (Newborough) towards the north. 

When the listing that became known as The Welsh P15s was being compiled, this hill was not included in either the main P15 list or the accompanying P14 sub list, as it possessed no contours of significance on either the Ordnance Survey 1:50,000 Landranger or the 1:25,000 Explorer map. 

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

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

Therefore, the addition of this hill to Welsh P15 status is due to LIDAR analysis, resulting in a 26.9m summit height and an 8.4m bwlch height, with these values giving this hill 18.4m of drop, which is sufficient for it to be included in the main list of The Welsh P15s. 

 

The full details for the hill are: 

Group:  Ynys Môn 

Name:  Tywyn Niwbwrch 

OS 1:50,000 map:  114, 115

Summit Height:  26.9m (LIDAR)                                                           

Summit Grid Reference:  SH 41937 62552 (LIDAR) 

Bwlch Height:  8.4m (LIDAR) 

Bwlch Grid Reference:  SH 41804 62760 (LIDAR) 

Drop:  18.4m (LIDAR) 

 

Myrddyn Phillips (October 2021)