Mapping Mountains – Trimble Surveys – Elenydd

22.10.20  Castell Faen Grach (SN 726 775) 

Castell Faen Grach (SN 726 775)

With lock down restrictions in Wales coming in to force at 6.00pm on the 23^rd October, and with the weather set fine for the day and improving during the afternoon, I wanted to visit the hills for one last time before the 17 day lock down was implemented. 

The hills I chose to visit are positioned to the west and south-west of Pontarfynach (Devil’s Bridge), and it is this area that drew me back again having visited adjacent hills on two recent occasions. 

Prior to visiting I’d spent time analysing LIDAR and came prepared with a series of ten figure grid references to each summit and bwlch.  By doing so this can improve the accuracy of Trimble placement and only then requires an assessment of the land based on the LIDAR co-ordinates before setting the Trimble up. 

LIDAR image of Castell Faen Grach (SO 726 775)

I’d planned a route taking in seven hills over six walks with six of these being P30s and one being a sub.  The route would take me west of Pontarfynach before doubling back and then heading south.  Online photographs showed many of the hills to have good profiles; with reports of my first hill of the day describing it as an absolute gem and a gorgeous hill, so my expectation was high and I was not disappointed. 

Castell Faen Grach rises like a miniature Cnicht in a typical pyramidal shape and today its rusted slopes of bracken were interspersed amongst stunted trees, the greened and yellowed bushes of gorse and an array of architectured rock.  The online descriptions were certainly correct! 

The summit cone of Castell Faen Grach

I approached the hill from the south and followed a bridleway heading toward the farm of Ty’n-y-castell and from there to a small disused quarry.  Although the day’s forecast was generally fine, there was an outside chance of a shower with the afternoon brightening up.  And although any breeze blown drops of rain would not fall until later, when I set off for this first hill of the day the sky was overcast with the summits of the higher hills to the east submerged under clag. 

Leaving the bridleway I followed steepening slopes up toward the summit cone.  The easterly slopes of this hill are now given over to sheep grazing with an attractive wooded area just below, and as I gained height a number of sheep looked my way, nonchalantly munching on their morning grass. 

The area of this hill’s summit is impressive with a series of steep mounds interspersed amongst small crags and rock.  Its high point is easily found and has a small cairn on it. 

After setting the Trimble up to gather its allotted data I stood below it on one of the steep slopes and looked out to my next hill which was directly west and only 2km away, between me and it was greened pasture and a myriad of small white dotted sheep. 

Gathering data at the summit of Casttell Faen Grach

Once data were gathered and stored I closed the equipment down, packed it away and before heading down I looked out toward Pen y Felin Wynt (SN 725 759) and Banc (SN 721 762), the latter easily pinpointed due to the high mast close to its summit.  These would be my fifth and sixth hills of the day and although relatively close to Castell Faen Grach it would still take many hours before I stood on their summits.  Leaving the summit cone I retraced my inward route back to the car and then headed further west to the second hill of the day; Fron Ddu (SN 703 775). 

 

Survey Result: 

 

Castell Faen Grach (significant name change)  

Summit Height:  315.2m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 72693 77587 (Trimble GeoXH 6000) 

Bwlch Height:  276.6m (LIDAR)

Bwlch Grid Reference:  SN 72614 77645 (LIDAR)

Drop:  38.5m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  12.22% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

For further details please consult the Trimble Survey Spreadsheet