Tuesday, 11 September 2018

Mapping Mountains – Trimble Surveys – Pegwn Mawr

13.06.18  Llywy (SO 055 704)

Llywy (SO 055 704)

When I visited the hills to the north of the Clywedog Brook on the outskirts of Abaty Cwm-hir in February 2016, I’d looked across the valley to the felled forestry on the summit of Llywy and made a mental note that I should visit this hill as soon as possible, it has only taken me 28 months to do so!

Llywy is just one of many hills in this area that have the misfortune to be swamped in conifer plantation, and as with many summits whose forestry is felled, the high point can be difficult to reach with a literal assault course to negotiate on the way to the summit, however there is compensation in doing this as at least you can see where you are going, as opposed to thick conifers where a hand-held GPS is usually the safest navigation tool to reach the top.

The afternoon was proving slightly muggy, and having already visited two Trichant hills further to the east I wanted a single hill to end the day on, one that was relatively easy and without much distance and ascent, and Llywy fitted this bill.

I approached from the north-east, having left my car in a large lay-by adjacent to a track heading in to the forestry that once swamped this hill.  I soon left the track and zig-zagged up a steep field where sheep nonchalantly grazed in the afternoon warmth.

Across the valley the forested summits of Cwm Cynydd Bank stared back, their regimented conifers dulled green and aerial like, pointing skyward.  As I gained height the houses of Abaty Cwm–hir came in to view, all was quiet, even the slight breeze that increased in strength the higher I got, only wisped across the land, occasionally a slumbering sheep would wake and quickly scatter as I slowly plodded up hill and approached, otherwise few stirred.

The forested tops of Cwm Cynydd Bank

At the top corner of the field an old wooden gate gave access in to the felled forestry beyond which was the high point, according to the map this was only a short distance away, but it still involved a number of diversions from a straight line approach as pitted holes, remains of tree stumps and a number of brambles coursed their usual obstruction.

The gate leading to what is now felled forestry

Saplings had already taken root, and for those wishing to visit this summit, the next couple of years will be the best as these will grow and do their utmost to obstruct.

One of many saplings that have already taken root

The summit area of Llywy is easy to identify, but it is now rutted in the remains of the forestry, however I decided to survey two positions, each vying for the hill’s high point, both close to the only remaining mature trees on the upper part of the hill, these were seemingly left as a large aerial poked beyond their high point, they also conveniently sheltered the Trimble from the strong south-westerly wind that had increased in strength.

Gathering data at the summit of Llywy

I took ten minute data sets from each position, and happily waited whilst the Trimble collected its 600 individual data points during each survey, sitting on a tree stump where my mind relaxed and wandered.

The summit of Llywy

Once data were stored I looked around the summit area and said my good-byes to the hill as I doubt that I’ll ever re-visit, not from want of doing so, more a realisation that other hills will call.  I slowly made my way back through the felled debris to the old wooden gate and headed down to the lane in the valley below and turned left for a short walk back to my car.

Survey Result:


Summit Height:  465.6m (converted to OSGM15)

Summit Grid Reference:  SO 05501 70424

Bwlch Height:  393.3m (LIDAR)

Bwlch Grid Reference:  SO 05187 70319 (LIDAR)

Drop:  72.3m (Trimble summit and LIDAR bwlch)

Dominance:  15.53% (Trimble summit and LIDAR bwlch)

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