Mapping Mountains – Trimble Surveys – Elenydd

31.08.14  Truman (SN 777 768), Pen y Garn (SN 798 771) and Bryn (SN 755 764)

The Cefn Croes Wind Farm

This was a walk that Mark had suggested partly as he wanted to visit the 537m hill that is listed in the Deweys as Banc Dolwen (SN 792 787), for many years this hill had the reputation for being the ‘Inaccessible Dewey’ as its upper reaches are covered in conifer plantation and forest tracks gave up their onward progress a few kilometres from the highest point.  Nowadays the tree bashing is a thing of the past as an access track has been bulldozed from the near Cefn Croes Wind Farm in to the forestry where the continuation of the relatively new forest track goes near to the high point.

We parked above Devil’s Bridge by the Jubilee Arch which was erected by Thomas Johnes of Hafod to commemorate the jubilee of King George III in 1810.  For many years the road used to go under this arch, but a heavy goods vehicle hit it a few years ago and when the arch was repaired the local authority also decided to build a new bit of road just on the southern side of it.  It now stands rather silently, its appearance resembling that of a folly.

The arch commemorating the Jubilee of George III

As we were getting our boots on a number of cars appeared and all occupants joined an ever increasing number of people who were milling about in the morning sunshine.  The person who had organised the walk for this group approached us with a slight knowing look and asked if were we Marilyn baggers, once we owned up to our sins he smiled and shook our hands and introduced himself as Rob Davies, Rob contributes to the RHB forum and told us he lived in Devil’s Bridge having been born in Tregaron.  He was leading the group up Pen y Garn, all the people were local to the area and with Rob’s encouragement many were experiencing their first ascent of their local big hill.  We chatted for quite a few minutes and then watched the group disappear up the forest track as we got our gear ready.

A chance encounter; meeting Rob Davies

The forest track that leaves the car park adjacent to the arch heads up to the Cefn Croes Wind Farm and open hillside, this then gives easy access to Pen y Garn, which is one of only three 2,000ft’s amongst the expanse of Elenydd wilderness.  On our way toward Pen y Garn we wanted to visit the summit of Truman, which is a 480m map heighted Pedwar just to the north-west of the track.

We approached Truman from its east on a track that diverged from the main forest track, Mark had read a report that there was a break in the trees from this track, we found some form of break that quickly disappeared and meant further progress was a bit zig zaggy.  However, as the conifers hereabouts were young saplings the going was never difficult and soon we were on the summit area. 

Pedwar bagging on Truman

The Trimble gathered data from two points, one in a slight clearing where Mark built a small neat cairn, the other amongst sapling trees.  The required accuracy was achieved quickly for the first data set, but the second took around 30 minutes as tree coverage obstructed satellite reception.  During this time Mark investigated a path that came up the hill from the north and headed south from the small clearing.  I remained hidden behind small trees pouncing on the Trimble every five minutes or so, willing it down to its 0.1m accuracy before data can be logged.  Mark reported back that the path headed down to our inward main forest track and was our way down, this route would be the easiest to bag this Pedwar, and once five minutes of data had been collected we re-joined the forest track and headed up toward turbine country.

The first point surveyed on Truman was in a small clearing

Almost hidden from view

The second point surveyed on Truman was amongst small sapling conifers

The Cefn Croed Wind Farm is operated by Cambrian Wind Energy Ltd with construction commencing February 2004 with the last turbine installed spring of 2005.  The turbines take in a land full of Deweys and Uchafion, before construction of the wind farm these hills were wild affairs with few paths and although approaching hillsides are swamped in conifer plantation, the hill land had openness to it, today gravelled tracks give ease of access and blades forever skim the sky. 

When the sky is blue with high wisps of late summer cloud these turbines can take on a surreal beauty, almost as abstract art they reach up piercing the blueness with straight metal arms of white.  They can be rather mesmerising as their hum of blade with darkened shadow whipping the ground.

Mark (bottom right of photo) dwarfed by one of the Cefn Croes wind turbines

The turbines approach on to land reaching a height of over 550m and within about 0.4km of the summit of Pen y Garn, the track we used for our ascent gave us access to open hill side and the southern grassy ridge of Pen y Garn.  I followed Mark up as he headed off to find the high point of the hill.

Heading for the summit of Pen y Garn

The summit area of Pen y Garn has a substantial wind shelter and triangulation pillar on it.  The wind shelter incorporates a spiral entrance and is situated next to the trig pillar.  As with many wind shelters it has been made to its present form from the remains of an ancient cairn, this one was once a Bronze Age round cairn, 15m in diameter and 0.4m high.  Close to the shelter and trig is a track that predates the wind farm and gives access to the hill from the south.

About 70 metres to the north of the trig the southerly track reaches a gate and land on the eastern side of the gate looks as high as the ground at the base of the trig.  As Mark examined the land by the trig I gathered two data sets, one either side of a fence beside the gate and then headed toward what is by far the best place for the high point and that is beside what was once the ancient cairn.  A number of large embedded rocks protrude from the ground on the periphery of the modern constructed shelter.  Mark had already pinpointed which one he thought to be the highest, I assessed them independently and narrowed it down to two, one of which matched Mark’s chose.  The Trimble was placed on this rock and gathered its customary five minutes of data.

One of two Trimble positions either side of the fence adjacent to the gate

The Trimble on the highest embedded rock next to the trig and wind shelter with the high ground beside the gate in background on right

Once butties had been scoffed we headed back down our inward route to re-join the forest track as it emerges out of the conifer plantation and followed it around the head of the Nant Rhuddnant.  This track now re-enters the forestry on the northern side of this high stream valley and gives easy access to the once formidable 537m map heighted Dewey.

Once back in forestry the track heads up to a forest ride at SN 793 787, it is this ride that gives access to the high point of the Dewey which is a few metres in to the conifers on the left hand side of the ride when approaching from the east.  We stumbled around claiming any high point and I placed the Trimble under a tree to see how it would cope with negligible satellite coverage.  Its initial accuracy was 13m, which made me smile, five minutes later it had improved to 5.5m, as we wanted to head toward our last hill of the day we had decided that 30 plus minutes of waiting for the accuracy to be achieved was not an option on this hill, so I then pressed ‘Log’ and waited for the Trimble to go AAHHDDAAAAHHHHDDHHHHHH!!!!!!!!

Mark at the high point of the Dewey listed as Banc Dolwen

Back on the forest track was rather a scrumptious affair as there were copious amounts of yummy blackberries, but we had to press on as our last hill of the day was way off over somewhere a good few kilometres away.  The track led down to open fields which gave access to a small bridge spanning the Nant Rhuddnant, this flowed down next to open fields on its north and a wasteland of bramble with a slender path on its south, and it was this path that we were now on.  It was all rather beautiful, no doubt seemingly so after many hours in a forest, but high slender grasses and late summer flowers blossomed as we tried to avoid the many boggy bits.

Beside the Nant Rhuddnant

The path eventually led on to open fields where a grassed track contoured around the northern slopes of our last hill of the day; named as Bryn on the Tithe map.  The hill rises above the farm of Bodcoll and when approaching from the direction we were it is shapely in appearance.  

The last hill of the day; Bryn

It has separate c 340m contour rings on the map at its summit, and as the Trimble gathered data at each high point a number of dogs in the farm yard below were alerted to our presence and started barking.

The penultimate data set at the end of another excellent walk

LIDAR image of Bryn (SN 755 764)

By now the sun of the day had been replaced by thickening cloud from the west and as we headed down the hill we were confronted by the dogs and owner, the former barked and the latter shouted at us.  Mark responded with apologies and I wondered if I should ask him what name he knows the hill by.  As he continued shouting I thought it prudent to head for the car which was on a direct course through a floundering bog, I gave up on this route and re-crossed a fence which only set off Mr Shouter with another barrage of hostilities.  This is the first occasion that I’ve encountered such hostility whilst being ‘lost’ on a hill, an unfortunate ending to an excellent walk.

Survey Result:

Truman

Summit Height:  480.9m (converted to OSGM15)

 

Summit Grid Reference:  SN 77711 76848

Drop:  34m  (Pedwar status confirmed)

Dominance:  7.07%

Pen y Garn

Summit Height:  611.0m (converted to OSGM15) (Hewitt and Nuttall status confirmed)

   

Summit Grid Reference:  SN 79853 77145

Drop:  c 194m

Dominance:  31.75%

Bryn (significant name change)

Summit Height:  340.7m (converted to OSGM15)

  

Summit Grid Reference:  SN 75568 76490

Bwlch Height:  307.6m (LIDAR)

Bwlch Grid Reference:  SN 75735 76460 (LIDAR)

Drop:  33.1m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  9.72% (Trimble GeoXH 6000 summit and LIDAR bwlch)

For further details please consult the Trimble Survey Spreadsheet