09.08.20 Y Garn (SJ 080 272), Y Clogydd (SJ 065 283), Moel
Crynddyn (SJ 059 278), Craig Rhiwarth (SJ 058
271) and Craig Rhiwarth (SJ 054 271)
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| Y Clogydd (SJ 065 283) |
Today’s walk was first
suggested by Aled a year or so ago and takes in hills above Llangynog, with a
number of surveying objectives including putting an accurate height to Y Garn;
a hill surveyed for summit position by John Barnard, Eric Hardman and myself a
number of years ago, and comparing the result of my basic levelling survey for
Moel Crynddyn against that produced by the Trimble GeoXH 6000.
The forecast was for
warming conditions as the day progressed, and we met in the car park in the
centre of the small community of Llangynog at 7.30am. Leaving one car here for our descent we then
headed through Penybontfawr and connected with minor roads and lanes above Cefn
Coch to the end of the paved section of road at over 370m.
From here a fence line led
uphill all the way to the summit of our first hill of the day; Y Garn. Leaving the car we were soon in murk which
covered all the higher hills east of Y Bala.
A cooling breeze gently swept across the land as we slowly ascended
chatting on the way and taking frequent rests.
Thankfully the forecast heat did not appear until later in the walk and
I found the whole ascent to the summit of Y Garn to be a pleasure.
The high point of our
first hill is a grassed area beside the ridge fence westward from the
triangulation pillar that looks down to the eastern lands when visibility is
good. Today it was still clagged in
cooling mist with dew soaked grasses wetting our boots.
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| Gathering data at the summit of Y Garn |
This was a hill I’d
wanted to survey with the Trimble for a number of years and it was good to be
here with Aled. The equipment was soon
set-up beeping away collecting its individual data points, by the time we’d
continued our chat the Trimble had gathered and stored eleven minutes of
data. Switching it off, we continued in
to the murk on a compass bearing heading north-westward to the connecting
bwlch.
The bwlch proved
expansive with copious amounts of tussock grass, with a few vehicle tracks on
the moor crossing this way and that and the customary boggy ground
pre-dominating. I’d noted two potential
positions, one where the 524m map spot height appears and another where
interpolation places the critical bwlch.
Both were Trimbled.
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| Gathering data at the bwlch of Y Garn |
I hadn’t been on these
hills in a number of years and although the higher tops and their connecting
ridge didn’t give us any extensive view, it was a pleasure being here wandering
through rough Berwyn territory with wafts of mist, breeze blown across the
land.
The next point to survey
was the summit of Y Clogydd which is one of the bumps leading from Post Gwyn to
Y Garn. Aled led us to the summit and
after it was surveyed, then down to its connecting bwlch. One data set from the summit and two from the
area of its bwlch were taken.
As the second bwlch data
set was being gathered the mist slowly rose giving the outline of a small
conifer plantation to our north-west, and peering skyward we kept thinking that
blue sky was only just above. The clear
blueness of summer never materialised, but loosing height from the bwlch and
finding the track leading toward the bwlch connecting with Moel Crynddyn, we
were now under the mist and watching as the summit of Craig Rhiwarth slowly
appeared in front of us, with the summit of Y Garn soon to be on view.
I’d surveyed Moel
Crynddyn for drop in October 2007; this was toward the end of using my old
basic levelling staff. The drop was
measured to be 15.0m, and both Aled and I doubted whether this hill would
survive in our Welsh Highlands – Uchafion
Cymru list after the Trimble data is processed.
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| Moel Crynddyn (SJ 059 278) |
Whatever the result for
Moel Crynddyn, it will not detract from the hill itself, as it is finely placed
overlooking a great sweeping drop down in to Cwm Glan-hafon. Having decided on the point to survey for its
bwlch the Trimble was set up in reed grass gathering its data.
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| Gathering data at the bwlch of Moel Crynddyn |
A vehicle track on the
grassed slopes of Moel Crynddyn led from the bwlch toward its summit, which is
positioned over the steep drop down to the cwm below. As the Trimble gathered its summit data we
sat looking down in to the upper reaches of the cwm as the light browned
outline of a Kestrel glided across the sky.
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| Gathering data at the summit of Moel Crynddyn |
Leaving the summit we
headed down as the muggy conditions started to take their toll. The next bwlch which connects to the higher
of the Craig Rhiwarth summits had been LIDARed by Aled and is placed in
forestry. This would not be Trimbled,
and we continued on a path beside a fence up toward the hill’s eastern top
which is positioned on a small outcrop of rock.
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| Y Garn (SJ 080 272) |
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| Heading toward the two Craig Rhiwarth tops |
I now needed to rest and
was thankful to sit down as the Trimble gathered its ninth data set of the
day. Its connecting bwlch had also been
LIDARed by Aled, so we bi-passed this on our way to the last summit of the day;
the higher of the two Craig Rhiwarth tops.
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| Gathering data at the lower of the two Craig Rhiwarth tops |
The upper part of this
hill contains the remains of an ancient Iron Age hillfort. The structure is enclosed by a wall which is
now no more than a line of tumbled rock.
According to Coflein a series of original entrances still exist and we
passed through one on our descent.
Within the walled enclosure are about 170 circular structures measuring
4 – 12 metres in diameter with a number of rectangular buildings also
present. The whole site is impressive.
 |
| Gathering data at the higher of the two Craig Rhiwarth tops |
The high point of the
hill is positioned a few metres from a proudly constructed cairn and soon the
Trimble was gathering its allotted data.
It was good to be here, high above the valley, on the summit of the last
hill of the day. Views were not
expansive as the grey murk still predominated, but outlined hills and their connecting
ridges were on show, giving a fulfilling end to the high part of the day’s
walk.
 |
| Heading down from Craig Rhiwarth |
From the summit it was a
steep descent firstly back to the hill’s bwlch passing through one of the
ancient entrances to the Iron Age hillfort, and then down following paths
through fern in to the cwm below, before a path leading through an old oak
plantation brought us on to a paved lane leading back to Llangynog.
 |
| Through the fern to the cwm below |
The walk had taken over
nine hours and five summits had been surveyed and in all ten data sets taken. The distance wasn’t great, with mist and murk
and high humidity as well as some rough underfoot conditions, but we had
achieved everything we wanted.
Survey Result:
Y Garn
Summit Height: 607.8m (converted to OSGM15)
Summit Grid Reference: SJ 08060 27282
Bwlch Height: 524.7m (converted to OSGM15)
Bwlch Grid Reference: SJ 07175 27787
Drop: 83.1m
Dominance: 13.68%
Y Clogydd
Summit Height: 595.6m (converted to OSGM15)
Summit Grid Reference: SJ 06565 28373
Bwlch Height: 583.5m (converted to OSGM15)
Bwlch Grid Reference: SJ 06425 28472
Drop: 12.2m
Dominance: 2.04%
Moel Crynddyn
Summit Height: 504.7m (converted to OSGM15)
Summit Grid Reference: SJ 05942 27845
Bwlch Height: 489.7m (converted to OSGM15)
Bwlch Grid Reference: SJ 05857 27931
Drop: 15.0m (Uchaf status retained)
Dominance: 2.97%
Craig Rhiwarth
Summit Height: 527.7m (converted to OSGM15)
Summit Grid Reference: SJ 05849 27105
Bwlch Height: 513.9m (LIDAR)
Bwlch Grid Reference: SJ 05623 27165 (LIDAR)
Drop: 13.8m (Trimble GeoXH 6000 summit and LIDAR
bwlch)
Dominance: 2.62% (Trimble GeoXH 6000 summit and LIDAR
bwlch)
Craig Rhiwarth
Summit Height: 530.9m (converted to OSGM15)
Summit Grid Reference: SJ 05484 27113
Bwlch Height: 462.6m (LIDAR)
Bwlch Grid Reference: SJ 05568 27592 (LIDAR)
Drop: 68.3m (Trimble GeoXH 6000 summit and LIDAR
bwlch)
Dominance: 12.87% (Trimble GeoXH 6000 summit and LIDAR
bwlch)
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