Mapping Mountains – Trimble Surveys – Cefn yr Ystrad

 

06.06.23  Mynydd Rhymni (SO 125 089) 

Mynydd Rhymni (SO 125 089)

Having visited Twyn yr Hyddod (SO 145 060) I drove the short distance down its mountain road to its connecting bwlch, which is positioned close to an attractive pond where a number of cars were parked and mountain ponies lazed in the early afternoon.  Beyond the pond Mark navigated us through the upper reaches of Tredegar toward another conveniently placed parking spot.  This was at the top of a housing estate, as I pulled up two people were carrying the debris of what looked like a week-long alcohol party from a shed.  I thought I’d better check if it was all right to park.  The next five minutes or so was rather entertaining as I listened to the lilt of south Walian accents as the larger of the two men remonstrated on all manner of things, all done in a friendly banterish sort of way, and all done with almost every second word a swear word.  I felt happy to have met a part of the valley culture which I have to admit I quite enjoy, although it is not one that I nowadays can instantly relate to.

Once permission to park was granted, which the friendly swearing man was more than happy to give and who seemed rather surprised to even be asked, we set off through a gate on a good earthen, bone dry track, leading past beautiful hawthorn bushes, all of which were toppling over in bloom. 

The start of the ascent to the summit of Mynydd Rhymni

We left the earthen track after a few minutes and headed up the hill over its grassed sides, skirting most of the reed infested ground which signalled wet stuff in usual times, but with no rain in south Wales for almost four weeks the ground was particularly dry, however this didn’t stop Mark from finding a good wet bog for us to walk through on our descent, which seems to be a penchant for him to do these days!

I followed Mark as he used his hand-held GPS to direct us up to the cairn atop the high point of the hill.  It was a pleasing ascent, with the sun now breaking through the high cloud cover adding welcome warmth to proceedings and which was in contrast to the first hill we both visited which proved a teense chilly with a brisk north-easterly breeze blowing. 

Nearing the summit

However, even though the sun had made an appearance the breeze still blew, and as the Trimble gathered allotted data at the summit of Mynydd Rhymni, Mark hunkered down in the lee of the breeze whilst I luxuriated in the almost perfect weather conditions for me on the hill; slight warmth with a slight breeze. 

Gathering data at the summit of Mynydd Rhymni

Once the Trimble had gathered and stored data I packed it away and suggested a route following a good path that would wind its way around the upper northerly broad ridge before sweeping down to the east and south, this I thought would bypass any reed infested ground and bog.  Mark pointed out that the initial route was going in the opposite direction to where we wanted to be.  Therefore I happily followed him down on a direct route back to the awaiting car that eventually tool us straight in to a reed infested bog.  I was happy enough in the bog as I was wearing my four season walking boots; however Mark was going light weight with just trainers as footwear.  It took us a while to extricate ourselves out of the marshy ground.

Once back on terra-firmer it was only a short walk down on to another earthen track which soon joined our inward route beside the access gate between the open hill and the housing estate.  On the way a number of Welsh Black cattle were munching in the afternoon sun, many lazily lying on the ground. 

Lazing in the sun

Back at the car we were soon ready to head off down the hill to skirt through Tredeger and up to the next mountain road, this one almost took us straight to the summit of Cefn y Brithdir (SO 120 043); or next hill of the day. 

 

Survey Result:

 

Mynydd Rhymni                       

Summit Height:  457.4m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SO 12593 08981 (Trimble GeoXH 6000)

Bwlch Height:  379.3m (LIDAR)

Bwlch Grid Reference:  SO 14083 07666 (LIDAR)

Drop:  78.1m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  17.08% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

For further details please consult the Trimble Survey Spreadsheet