Saturday, 13 January 2018

Mapping Mountains – Hill Reclassifications – Y Trechol – The Dominant Hills of Wales

Castell (SN 585 790) – Lesser Dominant addition

There has been an addition to the listing of Y Trechol – The Dominant Hills of Wales, resulting in this hill being added to the Lesser Dominant list due to its drop value being amended.

With the criteria for inclusion to the Dominant list being those Welsh P30 hills whose prominence equal or exceed half that of their absolute height, whilst the criteria for the Lesser Dominant list are those additional Welsh P30s whose prominence is 33% or more and below 50% of their absolute height.

During 2006 and 2007 the sub category of hills accompanying the Welsh P30 lists published on Geoff Crowder’s website were standardised and interpolated drop values also added, this hill was then listed with an estimated c 29m of drop based on its 73m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 44m, therefore as the drop value was under 30m it was insufficient for this hill to qualify for either the Dominant or Lesser Dominant list.  The drop value was subsequently altered to 31m due to a 41m bwlch spot height appearing on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website.

The name of the hill is Castell and it is adjoined to the Elenydd group of hills which are situated in the Region of Mid and West Wales (Region B, Sub-Region B2).  The hill is positioned above the Afon Ystwyth which encircles it on its eastern side, and has the town of Aberystwyth to its north.

As the hill is not a part of designated open access land permission to visit should be sought, for those wishing to do so the nearest public footpath leaves a minor lane to the hill’s south-east and contours around the northern base of the hill.

The qualification of Castell to Lesser Dominant status is dependent upon Ordnance Survey spot heights, with a summit spot height of 73m and a bwlch spot height of 42m given on the Interactive Coverage map hosted on the Geograph website, with these values giving this hill 31m of drop and 42.47% Dominance, which is sufficient for this hill to be listed as a Lesser Dominant hill.

The full details for the hill are:

Group:  Elenydd

Name:  Castell

Dominance:  42.47%

OS 1:50,000 map:  135

Summit Grid Reference:  SN 58519 79005

Summit Height:  73m

Drop Summit to Bwlch:  31m

Drop Bwlch to ODN:  42m  

Myrddyn Phillips (January 2018)

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