Mapping Mountains – Trimble Surveys – Carnedd Wen

 

25.02.21  Llwynderw Hill (SJ 196 036)

LIDAR image of Llwynderw Hill (SJ 196 036)

I’d visited this hill once before in June 2011 and on that occasion the circular walk from my home taking in its summit formed one of a number of preparation walks for the Fisherfield surveys conducted for The Munro Society.  Then I did not have a Trimble, now I do and the hill was within easy striking distance from my home for a socially distanced lock down walk. 

Prior to this re-visit I had examined the details for the hill via LIDAR and noted an accurate height and position for both its summit and bwlch, with the natural summit being prioritised over the higher field boundary. 

Llwynderw Hill is positioned overlooking the Severn Valley and can be easily accessed from the convenience of the Montgomeryshire Canal.  My walking companions for the day were Linda and Nic and we met beside the wharf next to Morrisons car park. 

Linda, Tommy the dog and Nic on the canal towpath

The ducks were shining their bright coloured feathers in the morning sunshine as we leisurely made our way out of town following the canal towpath.  This was a change from what has become the norm of using the Cefnyspin and Frochas Lanes to access Y Golfa and its adjacent hills.  And however beautiful and welcome that route had become it was good to have a change of scene. 

Beyond Belan Lock the opposite side of the canal was awash in dazzling Snowdrops, they shined back at us all whitened standing upright in the late February sunshine as the first warmth of spring continued to take hold. 

Admiring the Snowdrops

We left the canal towpath after almost three miles and headed west up a steepening narrow lane which although highlighted yellow on contemporary Ordnance Survey 1:25,000 Explorer maps, is not recommended to drive up as one steep section is particularly daunting where the paved section has crumbled leaving a ramp.  Thankfully, today we were walking and not attempting to drive. 

Nearing the high point of the narrow lane we accessed a field next to a gate and continued up toward the high point.  The girls found a sheltered spot to indulge in lunch, whilst I sauntered over to the summit zeroing in on the ten figure grid reference produced from LIDAR analysis for the natural high point.  I soon had the Trimble set-up gathering data and re-joined the girls whilst it quietly beeped away collecting its individual datum points. 

Gathering data at the natural summit of Llwynderw Hill

After five minutes data were gathered and stored, I closed the equipment down and sauntered back to join Linda and Nic sitting in the sunshine for a bite to eat and lots of good conversation. 

Nic engaging in an unusual self examination exercise!

We left the field and joined a public footpath leading to Cefn-hilin farm and then onward down the continuation of the lane to another public footpath which headed across fields, over a brook and then beside forestry.  It was beautiful.  It was also quiet and gave a sense of detachment from the world of Covid and lock down restrictions, with increasing warmth as late morning gave way to early afternoon. 

Our route toward Lower Pwll and the Red Lane

Friendly horse

The footpath led down to Lower Pwll and the Red Lane, which we happily followed past the entrance to Powis Castle and eventually back to our inward route on the canal towpath. 

The greens of late February

The walk took about seven hours and was very enjoyable and relaxed with good company, views, lots of laughs and another summit Trimbled.  It had been another good day on the hill!

 

Survey Result: 

 

Llwynderw Hill (significant name change)

Summit Height:  237.9m (converted to OSGM15, Trimble GeoXH 6000) 

Summit Grid Reference:  SJ 19600 03662 (Trimble GeoXH 6000) (summit relocation confirmed)

Bwlch Height:  159.7m (LIDAR)

Bwlch Grid Reference:  SJ 18827 03989 (LIDAR)

Drop:  78.3m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  32.89% (Trimble GeoXH 6000 summit and LIDAR bwlch) (Lesser Dominant deletion)

 

 

For further details please consult the Trimble Survey Spreadsheet