Craig Eigiau (SH 713
654) – 700m Sub-Twmpau addition
There has been an addition to the Twmpau (thirty welsh metre prominences and upward) list due to a survey with the Trimble GeoXH 6000, and a subsequent survey by Alan Dawson with the Leica RX1250, with this
hill being included in the 700m Sub-Twmpau. Accompanying all the 100m height band of
hills within the Twmpau are sub lists
with the one attached to this list being entitled the 700m Sub-Twmpau.
The criteria for 700m Twmpau
status is all Welsh hills at or above 700m and below 800m in height with 30m
minimum drop, the criteria for 700m
Sub-Twmpau status is all Welsh hills at or above 700m and below 800m in
height with 20m or more and below 30m of drop.
Details to this height band of the Twmpau
were published on the Mapping Mountains site on 15th April 2015.
Prior to the survey with the Trimble GeoXH 6000 the summit of this hill
had been analysed with LIDAR data by Aled Williams, resulting in a 733.9m height,
and it had remained listed as an Uchaf with
an estimated c 19m of drop based on the 735m summit spot height that appears on
the Ordnance Survey 1:50,000 Landranger map and the 1:25,000 Explorer map, with
an estimated bwlch height of c 716m based on bwlch contouring between 710m –
720m.
The name of the hill is Craig
Eigiau and it is situated in the Carneddau
group of hills and is placed in the Region of North Wales (Region A,
Sub-Region A1) with its Cardinal Hill being Carnedd
Llywelyn (SH 683 643). The hill is
positioned between two reservoirs; Melynllyn
to its west and Llyn Eigiau to its
east, with the small community of Tal-y-bont
to the north-east of the hill, and it can be visited via its northern ridge
which can be gained from a track leaving the high car park close to Llyn Eigiau, however it is more rewarding
to combine this hill in a longer walk with a number of its higher neighbours.
The survey with the
Trimble produced a summit height of 734.7m (converted to OSGM15) at SH 71314 65425 and a bwlch height
of 713.9m (converted to OSGM15) at SH 71185 65473, with these values giving this hill 20.8m of
drop, with the details from the Leica RX1250 survey conducted by Alan Dawson being 735.0m (converted to OSGM15) summit height at SH 71315 65425 and 714.1m (converted to OSGM15) bwlch height at SH 71191 65460, with these values giving this hill 20.9m of drop, which is sufficient for its addition to 700m Sub-Twmpau status. This now revises the total in
the 700m Twmpau which will be updated
accordingly.
The full details for the hill are:
Cardinal Hill: Carnedd
Llywelyn
Summit Height: 735.0m (converted to OSGM15, Leica RX1250)
Name: Craig Eigiau
OS 1:50,000 map: 115
Summit Grid Reference:
SH 71315 65425
Drop: 20.9m (converted
to OSGM15, Leica RX1250)
The overall total for the
700m Twmpau remains at 32 hills
with two reclassifications to 700m Sub-Twmpau status since publication of
this list on the Mapping Mountains site on 15th April 2015.
The overall total for the
700m Sub-Twmpau is now 7 hills with two reclassifications from 700m Twmpau status and one addition since
publication of the list on the Mapping Mountains site on 15th April
2015.
The list of 700m Twmpau
is available from Mapping Mountains (April 2015) with all subsequent
changes detailed in the 700m Twmpau – Hill Reclassifications on the Mapping
Mountains site.
The Trimble GeoXH 6000 gathering data at the summit of Craig Eigiau |
Myrddyn Phillips (July 2017)
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