Saturday, 21 August 2021

Mapping Mountains – Trimble Surveys – Carnedd Wen

 

02.07.21  Broniarth Hill (SJ 168 128) 

Broniarth Hill (SJ 168 128)

By the time I arrived at my designated parking spot the deep blued grey cloud of early morning was now lightened with small breaks heralding the onset of warmer conditions to come.  I had already visited Moel y Sant (SJ 152 107) and with another four hills planned, all of which only entailed short walks and surveys of their summits, I was looking forward to a continued morning’s bagging and surveying local hills before afternoon and evening commitments took me homeward. 

I’m not a fan of forested hills, occasionally they can make for an adventure or two, but in the main my enthusiasm is not heightened.  This is shown when I look through my maps as each hill is circled and the ones visited given a small line through the circle, not surprisingly many of the unvisited hills are those whose summit is forested and this was so with Broniarth Hill.  However, logs on the Hill Bagging website indicated an easy ascent with good views from the summit, something the map does not suggest. 

Prior to visiting this hill I had spent time analysing it and the other four hills on the morning’s bagging agenda via LIDAR; this is a resource that is proving indispensable for producing accurate numerical data, and the combination of surveying with the Trimble adds that important on-site element. 

LIDAR image of Broniarth Hill (SJ 168 128)

I opted for an ascent from the east following a part of Glyndŵrs Way and had parked my car and was walking toward the hill by 8.10am.  The cooling air from my earlier ascent of Moel y Sant had quickly been replaced by warming and humid conditions.  The route was indeed easy and gave a pleasantly quiet approach to the hill. 

Summer brings succulent growth and life to the hills and this was all too evident on my approach, with long grasses swaying in the slight breeze, mature trees laden with their greened leafs, a myriad of insects darting this way and that and colourful butterflies flitting between patches of sunlight.  It was a joy to be out on the hill and the route ahead led on a path across a field beside a wood, down to a connecting bwlch, where to the left the watered depths of Llyn Du stretched westward out of sight. 

Llyn Du

Ahead of the slight dip a narrow path led directly up steepening ground.  I had wondered if my route was further to the right but had fortunately decided to continue losing a little ground to see whether it continued from the dip, it did, and I was soon plodding my way up with Red Admirals spiralling around the path adding splashes of colour when they landed with their blacks and reds giving contrast to the greened surrounds. 

The path ahead leading up steepening ground

The path continued uphill with trees on each side and gave for a lovely walk to the summit.  Eventually it led to an open area and a wide forest track.  Ahead was a rounded knoll which was the remaining summit of the hill.  Either side of the knoll were wide forest tracks, the construction of which looked as if it had obliterated the natural summit.  Close by was a bench, which on hills of similar height usually is a welcome addition.  Seeing it I knew where I’d be when the Trimble was gathering summit data! 

The path through the wood

Standing on the summit there was indeed a good view and soon the Trimble’s internal antenna was aligned with the high point and placed on top of my rucksack, with the measurement offset between it and the ground below noted, and soon it was beeping away collecting its individual datum points.  The beeping is quiet, but it is a sound that I’ve become accustomed to and one that I find rather reassuring.  I suppose it tells me that an expensive bit of kit is still working! 

Gathering data at the summit of Broniarth Hill

During data collection I couldn’t resist sitting on the bench and enjoyed my few minutes rest whilst scribbling all necessary information in my surveying notebook.  Once all detail was noted I stood near to the bench and looked north-east down the tree lined northerly slopes of Broniarth Hill to the meanderings of the Afon Efyrnwy as it gently flowed eastward.  Rising above on its opposite banks stood Moel y Main, a fine hill with a goof profile, as indeed are many of the hills in this vicinity. 

The view north-east from beside the bench at the summit of Broniarth Hill

Soon the five minutes allotted data collection was up and I scampered back to the Trimble to close it down, take a few photographs, admire the view to the south, pack the equipment away, get my rucksack back on and head down the forest track to the narrow path leading down the hill. 

Patches of sunlight on Llyn Du

By the time I emerged out of the trees on to the open field giving the view of Llyn Du the cloud was breaking with patches of blue heralding increasing warmth.  My third hill of the day was only a short drive away and after negotiating the narrow lanes I was soon at the starting point leading up Dol Gron (SJ 171 137). 

 

Survey Result: 

 

Broniarth Hill

Summit Height:  265.0m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SJ 16861 12824 (Trimble GeoXH 6000) 

Bwlch Height:  218.2m (LIDAR)

Bwlch Grid Reference:  SJ 17303 12961 (LIDAR)

Drop:  46.8m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance: 17.66% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

For further details please consult the Trimble Survey Spreadsheet

 

 

 

 

 

 

 

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