Sunday, 1 November 2015

Mapping Mountains – Trimble Surveys – Moel y Gamelin


13.10.15  Caergwrle (SJ 306 571)  

Artists's impression of Caergwrle (SJ 306 571)

Caergwrle is steeped in history as it was the last castle built by the Welsh before the subjugation handed out to the country by its near neighbours across the border.  Construction of the castle began in 1277 but by 1282 it had been slighted by Dafydd ap Gruffudd as he retreated from the castle under the impending invasion by Edward 1.

The castle stands on top of a hill overlooking the fertile plains of Cheshire to its east and the small town that has taken its name from the castle; Caergwrle, at its base to the west.  It is listed as a grade 1 structure and its ruins are cared for by the Caergwrle Community Council.

There is a car park in the town that is free of charge that is just to the north of the castle which was full when I visited, however parking close to the car park can be found on adjacent streets.  I wanted to try and survey this hill’s critical bwlch and continued past the castle entrance to the top of the A 541, to my left (east) was undergrowth leading up to the castle ruins and to my right (west) were houses and bungalows.

The last bungalow in the town is situated where the road started to dip away downhill, beyond this bungalow is a field with a central wet area indicating the position of the land on the valley to valley traverse.  As I walked up the road the land to my right also climbed steadily, and although it consisted of bungalows their front drives and gardens steadily gained height up toward where the critical bwlch for this hill is situated.

This critical bwlch could be positioned on the drive of any one of the last three bungalows, I chose the central one, and as the ground hereabouts had been terra formed with gardens, drives and house construction I did not think that in the grand scheme of critical bylchau that it mattered much which one I chose.

However, the land was definitely going down on the hill to hill traverse toward the front door of the central of the last three bungalows, this door was positioned on the side of the building, therefore I needed to place the Trimbe in an enclosed space on the drive of this bungalow.  I knocked on the door and Pamela Jones answered, I smiled and we chatted, I explained my unusual hobby and told her about the Trimble and my need to survey her drive.  Pamela proved a delight to talk to and kindly gave me permission to set the Trimble up and gather data just outside her front door.

I had a potter around the back of Pamela’s bungalow and assessed her back garden, but decided that the critical bwlch was positioned a couple of metres from her front door in the centre of her drive.  Within a few minutes the Trimble was sitting on top of my rucksack and I’d measured a 0.44m offset and off it went beeping away gathering its allotted 300 datum points.

Gathering data on Pamela's drive

Pamela Jones - a lovely person to meet

Gathering data at the critical bwlch of Caergwrle

Once it had been packed away I knocked on the door and thanked Pamela for letting me survey her drive, she happily posed for a number of photographs and kindly said that I could put one on my blog.  Pamela proved a lovely woman to meet and I’m ever so grateful that she let a complete stranger in to her life for the ten or fifteen minutes that it took for the survey.

With bwlch data gathered I walked back down the road toward the town’s War Memorial, next to which a path led up toward the remains of the castle.  Across the A 541 Mynydd yr Hôb rose with its easterly slopes covered in deciduous trees, by the time I’d reached the remains of the castle the sun cast out warmth and my body was overheating due to wearing a fleece coat. 

I circled the castle’s remains and looked for the highest natural ground I could find, this proved to be a flattish rock outcrop above a large drop that overlooked ground to the west, at the base of this drop is where a 16th century millstone quarry was once situated, the workings of which cut deep in to the hillside coursing one wall and two towers of the castle to collapse.

Part of the castle's remains

As the Trimble ebbed down to its required 0.1m accuracy before data should be logged I sat on one of the castle walls and soaked up the sun and the atmospheric surrounds, only occasionally scampering off to check on the Trimble’s downward progress.  As the 0.1m figure glared back at me I quickly pressed ‘Log’ and retired back to my stone seat in the sun.

Gathering data at the summit of Caergwrle

After five minutes of data were collected I switched the equipment off, packed it away and contentedly wandered down the path and back to my car.  My last planned walk of the day was due south on the outskirts of Rhostyllen, which forms one of the south-west suburbs of Wrexham.  Above this Wrexham suburb is a mound of coal waste that looks down on the countryside and I’d wanted to visit this hill for a number of years and even more so now having a Trimble.  The hill is known locally as Hafod Bank and it consists of the remains of coal spoil from the Hafod Mine.  Would it reach P30 status?  I was betting that it would.    


Survey Result:



Summit Height:  137.8m (converted to OSGM15)

Summit Grid Reference:  SJ 30670 57148

Bwlch Height:  96.0m (converted to OSGM15)

Bwlch Grid Reference:  SJ 30592 57084

Drop:  41.9m

Dominance:  30.39%



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

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