Drum Boeth (SH 720 462) - 500m Sub-Uchaf reclassified to Uchaf
There has been a reclassification to the listing of Yr Uchafion instigated from analysis of
LIDAR data by Aled Williams and subsequently confirmed via a survey with the Trimble GeoXH 6000. Yr Uchafion is the draft title for a
list of the Welsh 500m P15s that takes in all hills in Wales at or above 500m
that have a minimum drop of 15m, the list is a joint compilation with Aled
Williams, with the details relating to this list being published on the Mapping Mountains site in November 2015.
The listing of Yr
Uchafion includes three sub lists; the 500m
Sub-Uchaf, 490m Sub-Uchaf and the
Double Sub-Uchaf category. The reclassification of this hill is from 500m Sub-Uchaf to Uchaf, with the
criteria for 500m Sub-Uchaf status
being all Welsh hills at or above 500m in height that have 14m or more and
below 15m of drop.
This hill is given an uppermost 520m ring contour
with no spot height on current Ordnance Survey maps and has bwlch contouring
between 500m – 510m, and prior to the analysis of LIDAR data the hill was
listed as a 500m Sub-Uchaf based on a
basic levelling survey conducted by Myrddyn Phillips on the 27th
October 2005, which resulted in a drop value of 48ft 6˝ (14.8m) which was
insufficient for it to qualify for Uchaf
status.
The hill is adjoined to the Arennig group of hills with its Cardinal Hill being Manod Mawr (SH 724 446) and is placed in
the Region of North Wales (Region A, Sub-Region A3). The hill is situated with the town of Blaenau Ffestiniog to the west
south-west and is positioned between the small mountain lakes of Llyn y Drum Boeth to the north-west and Llyn Du Bach to the south.
The hill can be accessed via a track that follows
the course of the Afon Teigl from
above Llan Ffestiniog or via public
footpaths from Blaenau Ffestioniog,
however current mapping shows that the summit of the hill is not on open access
land, although being close to it, and on a previous visit the land between each
is open and unfenced and therefore hard to distinguish where the open access
land ends, in situations like this common sense should prevail and if wanting
to visit the summit there is likely to be no objection to doing so.
The name of the hill is Drum Boeth and its reclassification from 500m Sub-Uchaf to Uchaf is
due to analysis of LIDAR data by Aled Williams.
LIDAR
(Light Detection & Ranging) is highly accurate height data that is now
freely available for much of England and Wales.
Aled’s analysis of LIDAR data gives the hill the
following details:
Drum Boeth
Summit Height: 523.4m
Summit Grid Reference:
SH 72020 46289
Bwlch Height: 508.3m
Bwlch Grid Reference:
SH 72161 46335
Drop: 15.1m
Therefore, the 523.4m LIDAR data produced for the
summit position at SH 72020 46289 and
the 508.3m LIDAR data produced for the bwlch position at SH
72161 46335 gives this hill 15.1m of drop, which is sufficient for its
reclassification to Uchaf status, with the details from the Trimble GeoXH 6000 survey being 523.4m (converted to OSGM15) summit at SH 72020 46289 and 508.1m (converted to OSGM15) bwlch at SH 72159 46335, giving this hill 15.2m of drop.
The full details for the hill are:
Cardinal Hill: Manod
Mawr
Summit Height: 523.4m
(LIDAR data and Trimble data [converted to OSGM15])
Name: Drum Boeth
OS 1:50,000 map: 115
Summit Grid Reference:
SH 72020 46289
Drop: 15.2m (LIDAR and Trimble summit data and Trimble bwlch data [converted to OSGM15])
This now brings the overall total for Yr Uchafion / The Welsh 500m P15s to 629 hills with the overall
total for the 500m Sub-Uchaf category
now being 25.
The additions, reclassifications and deletions to Yr Uchafion / The Welsh 500m P15s
reported on Mapping Mountains are as follows:
UCHAF ADDITIONS
500m SUB UCHAF RECLASSIFICATIONS TO UCHAF
Drum Boeth (LIDAR data) (SH 720 462) 500m Sub-Uchaf
reclassified to Uchaf with 15.2m of drop
UCHAF RECLASSIFICATIONS TO 500m SUB-UCHAF
UCHAF RECLASSIFICATIONS TO 490m SUB-UCHAF
UCHAF DELETIONS
 |
| The Trimble GeoXH 6000 gathering data at the summit of Drum Boeth (SH 720 462) |
Myrddyn Phillips and Aled Williams (April 2017)
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