Wednesday, 22 October 2014

Mapping Mountains – Trimble Surveys – Carnedd Wen


19.10.14  Y Byrwydd (SJ 145 045)  

Y Byrwydd (SJ 145 045)
Having visited Pen y Berth (SJ 0801 127) Mark and I headed down the B 4382 and onto the A 458 and turned out of Llanfair Caereinion on the B 4389 before finding the narrow lane that took us to the base of Y Byrwydd.

I’d visited this hill once before in October 2011, I was then on a bagging trip taking in six separate walks over a number of P30’s.  Today Mark wanted to visit two HuMPs, the first of which was Pen y Berth and the second being Y Byrwydd.

We parked in a lay-by at SJ 138 046 where there is room for one car, this is near to the track that heads toward Ashton Farm.  As we walked down the narrow lane inspecting the hedgerow for signs of the public footpath which would give us access into the field and the hill’s summit, the sky above was a vivid grey highlighted with sunshine.

Mark found the gap in the hedge giving access to the field and bashed a few brambles out of our way as we clambered over a wooden fence and into the green and pleasant pasture with sheep and cows as company.  There were more brambles at the next fence crossing; beyond this was a gate and the spacious grassed summit.

One brambled hedge negotiated, one more to go, Mark on the ascent of  Y Byrwydd
As the Trimble gathered its five minutes of data I admired the view which was extensive.  Away to the east were the hills around Welshpool with the Breiddin distinctive in their shape, Cefn Digoll and Corndon on the horizon, with Pen y Parc and Y Golfa nearer in view, all Marilyns and all on grand display.  To our north the view was of a heavy greyness obscured by shower clouds, these were also present to the west and although sunshine cast out to our south the showers were massing there as well, it was time to get down and inspect the bwlch.

Gathering data at the summit of Y Byrwydd
The critical bwlch of Y Byrwydd is on the narrow lane as it heads eastward from the summit back toward Llanfair Caereinion, the map contours indicate that the bwlch would be relatively easy to place.  When we arrived by car I parked in a small passing place and wandered down the lane to pick the spot for Trimble placement.  Considering that each side of the lane had hedgerows the Trimble attained its 0.1m accuracy before data can be logged remarkably quickly.  I pressed ‘Log’ and walked back a safe distance hoping that there wouldn’t be any passing vehicles in the next five minutes as the equipment was placed on the grass verge immediately beside the narrow road.

Bit risky placing Trimbles next to roads, you never know what might happen!

The opposite view looking west up the lane with the Trimble gathering data
As the Trimble was gathering data I tried to peer through the thick and high hedge to the south of the narrow lane to see the lay of land in the adjacent field.  Mark was doing the same but he had positioned himself sitting on the side of the roof of the car, the hedge proved thick enough that neither of us could get a good view into the field.  The adjacent field to the north of the lane headed up toward the road indicating that either the lane or the field to its immediate south was where the critical bwlch was placed.

Dedicated to the course, Mark sitting on the roof of the car trying to see into the adjacent field
Once five minutes of data were collected I drove further east and found a gate giving access into the southerly placed field, we wandered around for five minutes assessing the lay of the land as it headed up toward the hedge and the lane on the opposite side, indicating that the critical bwlch for Y Byrwydd is placed on or beside the narrow lane.

Happy in the knowledge that the hill and its bwlch had been surveyed we headed back to Welshpool for soup, toast and scotch pancakes – yummy!



Survey Result:


Y Byrwydd

Summit Height:  372.7m (converted to OSGM15) 

Summit Grid Reference:  SJ 14570 04563

Bwlch Height:  269.5m (converted to OSGM15)

Bwlch Grid Reference:  SJ 11597 05010

Drop:  103.2m (Hump status confirmed)

Dominance:  27.68%











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