Mapping Mountains – Trimble Surveys – Mynydd Hiraethog

22.08.14  Bryn Trillyn (SH 947 590)

Bryn Trillyn (SH 947 590)

Bryn Trillyn is positioned on the western fringe of Mynydd Hiraethog and looks out on desolation of moor.  It is easily accessible from the A543 which is just to its south-east.  The hill forms part of an extensive upland between the Welsh coast to the north, the Afon Conwy to the west, the hills of the Arennig to the south and the Afon Clwyd to the east.

This was my fourth and last walk of the day, and the second with Mark.  We’d just had a magical illuminated hour in the company of Moel Tywysog (SH 984 657) and confirmed its Pedwar status with a Trimble survey, we now wanted to watch the sun disappear behind the higher Eryri peaks and collect data to see if this 496m map heighted hill could become a fully-fledged Dewey.

We parked in a lay-by a few hundred metres south of the Sportsman’s Arms (SH 952 590).  This house is now for sale, it was once reputed to be the highest Inn in Wales, but the beer stopped being served a number of years ago.

We walked back up the road toward the Sportsman’s Arms and headed west over a foot stile on to a track, this leads to the summit of Bryn Trillyn, we diverged from the track and followed a fence line toward the heather moor.  Bearing left at the next fence junction directed us straight for the summit with reclaimed sheep pasture on the southern side of the fence and heather on the northern.  Mark chose the latter and I the former to walk on.  The heather was ablaze with delicate purples, all colour slightly diffused as the sun sank behind a thickening grey sky to the west.

Heading for the summit of Bryn Trillyn

We were now walking on a heather embankment which led straight to the high point of the hill, at one time this may have been a walled construction, but now nature has re-claimed it.  After we reached the summit Mark went off to investigate the ruin of Gwylfa Hiraethog, whilst I set the Trimble up on its improvised tripod on the high point of the hill.  This was on the heather embankment, and was something Mark and I discussed, as it may have once been a wall, but we both thought it could now be considered part of the hill, if indeed it had ever been some form of a wall.

Mark approaching the high point of Bryn Trillyn

As the Trimble attained its 0.1m accuracy and data were collected I looked up and Mark was standing in the centre of the ruin, much higher than my position as the rubble of the old house had been in situ long enough for it to be stabilised and for grass to grow on it, however we both agreed that this was definitely man-made.

The ruined Gwylfa Hiraethog

The subtle grey of the northern Carneddau

Gathering data at the first of three positions

Gwylfa Hiraethog was once a shooting lodge of Hudson Ewbanke Kearley; the first Viscount Devonport, whose main estate was Wittington House in Buckinghamshire.  Its origins date to the early 1890’s when a wooden chalet was erected; this was transported from Norway in prefabricated sections.  The chalet was later incorporated in to a larger stone built lodge, this was later enlarged in 1913 under the guidance of the architect Sir Edwin Cooper, photographs show the lodge as an imposing mansion in the Jacobean style, with a three gabled front with cross wings, long windows and a stone flagged floor.

Gwylfa Hiraethog was once an impressive house which was used as a shooting lodge

The Gwylfa Hiraethog estate was put up for sale by Viscount Devonport in 1925, it was then described as a shooting box with residence comprising 11 principal bedrooms, two secondary bedrooms and servant’s quarters.  Following the sale the lodge became the residence of the estate gamekeepers and was finally abandoned in the 1960’s.  Its subsequent deterioration has been rapid and it now stands as a ruin.

By now the thickening mass of grey cloud to the west was shielding the sun with only a flicker of piercing orange tailing out to the north, as the black outline of hills mirrored the deep blue of the sky.  This only lasted a few minutes as the blaze of sun disappeared from view, supplanted by twilight’s darkening.

The sun piercing the cloud and tailing out to the north

I definitely wanted to discover a new Dewey and insisted that the rubble strewn inner part of the abandoned old shooting lodge could definitely constitute the summit of a hill!  Therefore five minutes of data were collected from inside the house atop the grassed rubble.

Gathering data at the second of three positions

During this Mark investigated the moor and found a point that looked to be the highest outside of the heather embankment, once the Trimble had gathered its five minutes of allotted data from the top of the rubble summit I headed toward Mark.

Mark stands at the point for the third survey with his walking pole at the high point of the embankment on right of photo

In darkening conditions the Trimble was placed on its improvised tripod at the point Mark had found.  By now photography without the aid of using a flash resulted in a blurred image, once data were stored we headed down the grassed track back to the Sportsman’s Arms and the awaiting car.  Three points surveyed and my vote definitely goes toward the rubble summit!

Tryfan in centre background

Gathering data at the last of three positions

Survey Result:

Bryn Trillyn

Summit Height:  496.4m (converted to OSGM15)  

Summit Grid Reference:  SH 94748 59094

Bwlch Height:  446.5m (converted to OSGM15, from subsequent Trimble GeoXH 6000 survey)

Bwlch Grid Reference:  SH 96287 59668 (from subsequent Trimble GeoXH 6000 survey)

Drop:  49.9m

Dominance:  10.05%

 

 

For details on the bwlch survey of Bryn Trillyn

For further details please consult the Trimble survey spreadsheet click {here}