Showing posts with label Craig y Merwydd. Show all posts
Showing posts with label Craig y Merwydd. Show all posts

Monday, 6 August 2018

Mapping Mountains – Trimble Surveys – Cadair Idris


23.05.18  Braich Ddu (SH 645 120), Ffridd Uchaf Cregennan (SH 647 128) and Craig y Merwydd (SH 644 134)

Ffridd Uchaf Cregennan (SH 647 128)

With a continued forecast for blue skies and warmth, I visited hills adjoined to the western part of the Cadair Idris range which are positioned above the small community of Arthog.  I thought three hills should give me my mountain fix, and with a fourth tagged on close to the Arthog Bog I would no doubt be a happy bunny by the end of the day.

I was walking by 8.00am having parked my car at a junction of minor paved roads adjacent to a track, with one leading north toward Arthog, one being the continuation of the road I had driven on and leading to the farm of Bron-lletty-ifan and the adjacent track leading south toward my first hill of the day.

The track leading toward Braich Ddu 

It was stunningly beautiful in the early light with hillsides ablaze in green and all beneath an iridescent blue sky.  In the distance the profile of Pared y Cefn Hir as ever stood out, whilst the great bulk of Tyrau Mawr shot skyward in a shimmering blue tinged silhouette.

Tyrau Mawr

The track led to the bwlch connecting Ffridd Uchaf Cregennan with Braich Ddu, with the critical point being on the gravelled track, and I sat in sunshine happy with life as the Trimble beeped away collecting its individual datum points.

Gathering data at the critical bwlch of Ffridd Uchaf Cregennan

I’d only visited my next hill; Braich Ddu once before in February 2000, I decided a direct ascent would be fun and followed a sheep path upward before crossing to the east side of the fence that steadily climbs this flank of the hill, in time I popped out on to leveller ground and regained my breath before continuing to the high point.

Watchful sheep

The summit ridge of Braich Ddu has now unfortunately been churned up by off-roaders with deep trenches where grass once grew; it’s a shame to treat a hill in such a way.

A sad reflection of the times

The Mawddach estuary stretched below with tidal sandbanks meandering amongst blue waters, with Fegla Fawr and Fegla Fach prominent as wooded landlocked islands.

The summit of Braich Ddu was easily identified and within a few minutes the Trimble was gathering its allotted data, once data were stored and the equipment packed away I continued down the hill’s broad south-westerly ridge to the gravelled track that I had left an hour or so previously, this swung around the northern section of the hill and led me back to the bwlch that I had earlier surveyed.

Gathering data at the summit of Braich Ddu

Approaching Ffridd Uchaf Cregennan

Above the bwlch to the north lay the summit of Ffridd Uchaf Cregennan and a slow plod up the hill led to its attractive summit, and within a few minutes the Trimble was sitting atop my rucksack with its internal antenna aligned with the high point of the hill and a measurement offset noted.

Gathering data at the summit of Ffridd Uchaf Cregennan

The ever present Tyrau Mawr

My route to the next hill was back down the inward track to my car, as I started walking up the continuation of the paved lane toward the next bwlch a quad bike appeared heading up the Arthog road from the north, I waved and walked back down the road and once the quad bike had reached me it stopped.

I spoke with Emlyn Lloyd for quite some time and could easily have carried on doing so as he proved a wonderful person to speak with, full of gently given knowledge and as with so many farmers who I’ve met over many years, only too willing to impart this knowledge.

Emlyn Lloyd

The hill I had just surveyed is a part of Emlyn’s land and is known as Ffridd Uchaf Cregennan, this is the highest ffridd of Emlym's farm; Cregennan, which is situated further along the narrow lane to the north.  He confirmed the name of my next hill; Craig y Merwydd, and gave me a name that other farmers had also given me when I started my place-name research many years ago, for the higher hill which is named as Braich Ddu on the map.

As I waved goodbye to Emlyn I followed his quad bike up the road to the connecting bwlch with Craig y Merwydd, the critical point was immediately below the narrow road in what was once either a stone built house that now lay beside the road in ruin, or an old sheepfold.

Gathering data at the critical bwlch of Craig y Merwydd

The morning was so becalmed in beauty that I was happily taking ten minute data sets instead of the customary five, being more than happy to sit in the sun and let my mind wander to all manner of things and places and listen to those distant and dim beeps as each datum point was stored, sometimes life can be a simple affair and this, I think, is one of the joys of the hills as they have capacity to strip away periphery detail and concentrate one’s mind on the here and now, which for me this morning involved quiet contemplation.

Just one summit remained to survey before I headed down to visit a vegetated landlocked island beside the Arthog Bog, and that summit was Craig y Merwydd. 

Craig y Merwydd is a rocky lump of a hill with two distinct summits and both were Trimbled.  Whilst data were gathered I sat below the high point looking out to sea in a stunningly beautiful land being warmed by sunshine cast out of a forever blue sky, it felt good to be alive.

Gathering data at the summit of Craig y Merwydd

Pared y Cefn Hir

Once data were stored and the Trimble closed down and packed away I made my way off the hill and back to the minor lane to my car and proceeded to drive north toward Arthog and my last hill of the day; Ynys Gyffylog.    



Survey Result:


Braich Ddu

Summit Height:  545.8m (converted to OSGM15)

Summit Grid Reference:  SH 64536 12066

Bwlch Height:  494m (spot height)

Bwlch Grid Reference:  SH 65371 11430 (spot height)

Drop:  52m

Dominance:  9.48%





Ffridd Uchaf Cregennan (significant name change)

Summit Height:  351.9m (converted to OSGM15)

Summit Grid Reference:  SH 64745 12858

Bwlch Height:  325.0m (converted to OSGM15)

Bwlch Grid Reference:  SH 64787 12795

Drop:  26.9m

Dominance:  7.65%





Craig y Merwydd

Summit Height:  295.7m (converted to OSGM15)

Summit Grid Reference:  SH 64413 13459

Bwlch Height:  261.2m (converted to OSGM15)

Bwlch Grid Reference:  SH 64605 13317


Dominance:  11.70%




Thursday, 17 May 2018

Mapping Mountains – Hill Reclassifications – 200m Twmpau


Craig y Merwydd (SH 644 134) – 200m Sub-Twmpau reclassified to 200m Twmpau

There has been confirmation of a reclassification to the 200m Twmpau list due to LIDAR analysis conducted by Myrddyn Phillips and subsequently confirmed via a survey with the Trimble GeoXH 6000, with the criteria for this list being:

200m Twmpau - Welsh hills at and above 200m and below 300m in height with 30m minimum drop, with an accompanying sub list entitled the 200m Sub-Twmpau with the criteria for this sub category being all Welsh hills at and above 200m and below 300m in height with 20m and more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

This hill was listed in the Hills to be surveyed sub list when the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website as it did not meet the criteria then used for the main P30 list; however this list has now been standardised and interpolated heights and drop values also included, resulting in this hill being listed with an estimated c 32m of drop, based on the 296m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 264m based on bwlch contouring between 260m – 270m.  This drop value was later amended to c 33m based on the larger scaled contours on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website.

The name of the hill is Craig y Merwydd (composition given as Craigymerwydd on contemporary maps) and it is adjoined to the Cadair Idris group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), and the hill is positioned overlooking the A 493 road to its north-west and has the small community of Arthog to the north.

Craig y Merwydd (SH 644 134)

Extract from the Ordnance Survey series of Six-Inch maps

As the upper section of the hill is a part of designated open access land an ascent from most directions is feasible, with a minor road to its immediate south giving the easiest option.

The confirmation of the reclassification of Craig y Merwydd to 200m Twmpau status is due to LIDAR analysis conducted by Myrddyn Phillips.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 


The 1m DTM LIDAR analysis gives the hill the following details:


Name:  Craig y Merwydd

Summit Height:  295.5m

Summit Grid Reference:  SH 64413 13459

Bwlch Height:  261.0m

Bwlch Grid Reference:  SH 64606 13315

Drop:  34.5m


LIDAR image of Craig y Merwydd

Therefore, the 295.5m LIDAR analysis for the summit position at SH 64413 13459 and the 261.0m LIDAR analysis for the bwlch position at SH 64606 13315 gives this hill 34.5m of drop, with the details from the Trimble GeoXH 6000 survey being 295.7m (converted to OSGM15) summit at SH 64413 13459 and 261.2m (converted to OSGM15) bwlch at SH 64605 13317, giving this hill 34.6m of drop, which confirms its reclassification to 200m Twmpau status.


The full details for the hill are:

Group:  Cadair Idris

Name:  Craig y Merwydd

OS 1:50,000 map:  124

Summit Height:  295.7m (converted to OSGM15)

Summit Grid Reference:  SH 64413 13459

Bwlch Height:  261.2m (converted to OSGM15)

Bwlch Grid Reference:  SH 64605 13317

Drop:  34.6m (converted to OSGM15)



The Trimble GeoXH 6000 gathering data at the summit of Craig y Merwydd

For details on the survey of Craig y Merwydd

Myrddyn Phillips (May 2018)