Monday 10 February 2014

Mapping Mountains – Trimble Surveys – Hirddywel



09.02.14  Oldchapel Hill (SN 976 807)

Oldchapel Hill (SN 976 807)

Oldchapel Hill rises above the small community of Tylwch (SN 969 800) a few kilometres from the larger town of Llanidloes in the heartland of mid Wales.  Its land is hemmed in to the west by the Dŵr Tenau and to the east by the Nant Feinion, two small water courses that feed in to the Afon Dulas as it flows downstream toward the Afon Hafren (River Severn).  Following the course of the Dulas are the remains of the Builth to Manchester railway line, another vestige of railway closer with the Cambrian Railways station at Tylwch closing in 1962.

I’d only visited the hill once before in January 2003 whilst doing a 13 mile circuit starting with 326m Gorn Hill (SN 968 845) and finishing with the 371m Brynposteg Hill (SN 960 822) and taking in four 300m P30’s and five Pedwar hills.

Today’s walk was suggested by Mark who hoped to visit three HuMPs interspersed with a pub lunch.  This plan was dependent upon the weather whose mood was supposed to be particularly foul until the early afternoon.

Oldchapel Hill only just squeezes in to the category of HuMPs as it’s listed with 100m of drop, based on a 426m summit spot height and an interpolated bwlch height of 326m.  Could Mark be responsible for bagging a HuMP and at the same time deleting it from the list!?!

As we drove towards Llanidloes the quieter grey skies turned an ominous deep and dark grey and the first signs of heavier squally rain started to fall.  After finding a convenient parking place for the ascent of the hill we drove a few hundred metres further down the road to investigate the area of the bwlch.  Mapping suggests the critical bwlch is placed on or very close to the road just eastward of a farm named The Cross.

Thankfully the narrow lane widened enough for us to park and investigate where the critical bwlch lay.  Either side of the road are fields, that today were awash with water, so much so that pinpointing the critical bwlch, a task we thought may prove difficult, was in fact very easy as so much water had fallen over the winter months that each field, either side of the road, had the start of a stream in it originating from the sides of the road.  All we had to do was connect the two water courses and pick the highest road side grass verge.  This proved to be beside a culvert, not surprising as one would expect such a thing to be installed at the low point of a road.

As the boundary hedge was adjacent to the road I set the Trimble up on its pole, which was stuck in to the grass verge and awaited its 10 minutes of data collection.  Mark had sensibly retired to the car as intermittent rain persisted to fall.  The only passing vehicle was a tractor which slowly made its way across the bwlch toward unknown pastures that wherever they lie were going to be very wet.

The Trimble GeoXH 6000 set up on its pole at the critical bwlch of Oldchapel Hill


The area of the critical bwlch with the only vehicle that passed during data collection

Once the equipment was packed away we headed back to our parking place for the ascent of the hill.  This is when the waiting game began, as showers were hurtling across the land.  We’d occasionally sneak out of the car and look south-west in to a great mass of evil looking murk knowing that it was heading our way.  Eventually we had to make a move as that promised pub lunch could not wait much longer.

We followed a narrow lane up until a vehicle track made its way southward across a field heading toward the summit of Oldchapel Hill.  The ground was very wet and upon Mark’s suggestion we both wore wellies, a very wise decision.  As height was gained I looked back as Mark followed and all I could see was grey hills in the background.  The whole sky looked like thunder, a deep grey hue pervading all around.

Mark on the ascent of Oldchapel Hill

Once at the summit Mark set up his hand-held GPS and I placed the Trimble on the highest bit of grass, we took two data sets from the summit with the second on the highest bit of rock that was a part of the elegant rocky rib that makes up the summit.  By this time the thunderous murk had well and truly descended upon us as the rain and wind howled across the hill.  I quickly gathered handfuls of moss, squashed them tightly together and placed them either side of the Trimble to try and secure it in place.  Ten and seven minutes of data respectively was collected.  By the time the equipment had been packed away my fingers were squealing out with chill.

The summit of Oldchapel Hill was a particularly soggy spot yesterday

The descent was a soggy affair but soon we were back at the car with a local farmer stopping to strike up conversation, Mark explained where we had been and even asked about the name of the hill; Oldchapel Hill was confirmed and no Welsh alternative was known.  The man then recommended the carvery in the Red Lion in Llanidloes and within half an hour we were in the warmth of the pub with a full plate of food and outside the rain continued to fall! 



Survey Result:


Oldchapel Hill

Summit Height:  426.2m (converted to OSGM15)

Summit Grid Reference:  SN 97602 80712

Bwlch Height:  325.7m (converted to OSGM15)

Bwlch Grid Reference:  SN 98412 81808

Drop:  100.5m

Dominance:  23.58%




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

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