Mapping Mountains – Trimble Surveys – Hirddywel and Beacon Hill

16.05.15  Pt. 422.3m (SO 073 822) and Bryn Cwm y Rhiwdre (S 075 837)  

Pt. 422.3m (SO 073 822)

These two hills are a part of the Pegwn Mawr and Beacon Hill range respectively and are separated by the infant Camnant as it flows down from higher hills to the west.  When combined the hills make a good small circuit and their slopes are easily accessible via public footpaths.

I parked where the narrow lane has been widened on both sides next to a thin sliver of fir trees at SO 082 804, and walked a few metres up the road to a gate and then followed a small path as it contoured around the easterly slopes of Bryn Cwm y Rhiwdre before it confidently slipped down the hillside and crossed the Camnant just below the buildings that are named Ty’n-y-waun on the map.

The infant Camnant

Ty’n-y-waun had been a point to aim for as the path I was on contoured its way toward it, and as I walked up the opposing banks above the stream I was greeted by the yellowed faces of mountain pansies (viola lutea) springing up rather delicately from the grass below.

Mountain pansies, delicate and beautiful

A track led from Ty’n-y-waun toward where I wanted to go, I initially opted for a field, but soon ventured across to the track which led toward a thin strip of mature conifers that separated the south-easterly high point of the first hill I wanted to visit and its north westerly slopes.

Bryn Cwm y Rhiwdre with its single wind turbine

Another track led off from the one I was on and cut through the thin strip of conifers, a quick straddle of a fence brought me out onto a field which led up and through another even thinner strip of scrub and trees to the high point of the hill that we currently have listed in Y Pedwarau by the point notation.  This will alter for the 2^nd edition of the booklet as Aled has done a lot of work in documenting the locally known names for the hills hereabouts.

As I placed the Trimble down on the high point and set it to gather data I looked out on the green land surrounding me, all was quiet with hills that are seldom visited, with track ways and small paths leading one to another.

Gathering data at the summit of Pt 422.3m, the soon to be deleted Pedwar

Packing the Trimble away I opted to use a gate that led into a field and down to another gate toward this hill’s critical bwlch, instead of heading directly down to a green track which would have taken me to the bwlch.

The critical bwlch for this hill has a green earthen embankment running parallel with its hill to hill direction, which I discounted as man-made; I placed the Trimble down at the edge of the lower section of the embankment and left it to gather its customary five minutes of data.

Gathering data at the critical bwlch for the now deleted Pedwar

The continuation of the path I was on went between two smart barb wire fences, and as it had sapling trees rooting throughout its length I opted to walk in the adjacent field and aimed for another small grouping of conifers, at which point the path gained a track and veered right toward the western confines of Llyn Dŵr.

Llyn Dŵr nestles amongst reclaimed land and brings a welcome touch of wilderness to this land

This lake nestles against grazing land and brings an element of welcome wilderness to the area.  I walked up to its reed infested western side and looked out toward the two wind turbines that sprout up from the summit area of the hill I had just visited.  All around was quiet with the occasional buzzard overhead and a multitude of specks of white indicating why so much land had been turned over from its moorland state.

The two wind turbines on the northerly part of the summit area on the deleted Pedwar

Leaving the lake I followed the track past a building and quickly nipped down a field to cross the Camnant again, this time my crossing point was directly below the steep western side of Bryn Cwm y Rhiwdre.  I pottered up the slopes to the single wind turbine that adorns the summit area.

The view south-west approaching the summit of Bryn Cwm y Rhiwdre

Thankfully the wind turbine isn’t positioned on the highest point of the hill, and once the Trimble was set up I left it to gather its five minutes of data.  To the north-east the distinctive and eloquently shaped Glog stood out with small patches of yellowed gorse still intact.

A single wind turbine is positioned close to the high point of Bryn Cwm y Rhiwdre

The shapely profile of Glog (SO 091 852)

Leaving the summit a track led from the turbine down to the narrow lane toward my car, but I still wanted to take a data set from this hill’s critical bwlch which is positioned close to where my car was parked.

I took two data sets in all, one from a field to the south of the lane and one from the low point of the road which is just south-west from where the 373m spot height appears on Ordnance Survey maps.

The first data set for the critical bwlch of Bryn Cwm y Rhiwdre was taken from a field

The second data set for the critical bwlch of Bryn Cwm y Rhiwdre was taken from beside the road

After data were gathered I sauntered back to the car and checked on my route to the next hill as I still had one walk and a water level to survey.

Survey Result:

Pt. 422.3m

Summit Height:  422.3m (converted to OSGM15)

Summit Grid Reference:  SO 07382 82231

Bwlch Height:  393.2m (converted to OSGM15)

Bwlch Grid Reference:  SO 07104 82585

Drop:  29.0m (Pedwar reclassified to 400m Sub-Pedwar confirmed)

Dominance:  6.88%

Bryn Cwm y Rhiwdre

Summit Height:  406.9m (converted to OSGM15)

Summit Grid Reference:  SO 07557 83773

Bwlch Height:  374.0m (LIDAR)

Bwlch Grid Reference:  SO 08282 83991 (LIDAR)

Drop:  32.9m (Trimble summit and LIDAR bwlch)

Dominance:  8.08% (Trimble summit and LIDAR bwlch)

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