Mapping Mountains – Trimble Surveys – Cilfaesty

14.07.21  Trehafren Hill (SO 100 910) 

Trehafren Hill (SO 100 910)

Many years ago I lived in Trehafren; a housing estate in Newtown.  Then I never realised this hill existed, although I’m sure I noticed it as I drove in and out of the estate to go to work each day.  It is a fine small hill, one that in the main consists of grass with the usual stunted trees and brambles dependent upon one’s approach. 

I only realised its existence when I started compiling the Welsh P30 lists that where published on Geof Crowder’s v-g.me website and Mike Grant’s Evergreen website.  When I first came upon it on the map I was surprised; a P30 in the middle of Newtown.  It is hills like this that make the P30s so wonderful to visit; they consist of an abundance of variety from grandiose 3,00oft’s to grassy hills in housing estates. 

Having driven in to the housing estate I stopped my car, wound down the window and enquired with a man whether he was local, and if so whether he knew where a path started to visit the hill.  He had a push chair and baby with him and was suffering in the heat which was rapidly building up compared to the cooler climes of 6.30am when I stood on top of Pen y Gelli (SO 180 909); my first hill of the day. 

He directed me to the second turning on the right where a car park was situated, and asked me to wait for him there until he scouted out the route.  By the time I had got all necessary equipment and locked my car, he had come back around the corner and told me to turn left just beyond a green fence where a small gate then gave access to the hill. 

I was thankful of his help as on my previous visit to this hill in January 2004 I approached from the north through undergrowth, and that was in the winter, today in high summer the path I was directed toward was a great help.  But even this was overgrown in its initial part.  Once past the long grass, brambles and a rogue nettle or two, I followed a path through the long grass to the gravelled section which now forms a part of a BMX circuit on the hill. 

Just through the initial brambles and the narrow path leads toward the summit of the hill

Following the BMX circuit for a while I then joined a path through grass leading to the hill’s high point.  The summit is a marvellous viewpoint with the northern section of the Pegwn Mawr hills away to the west and the ridge with the two summits each known as Top Field (SO 114 890 and SO 110 879) that I had just visited and surveyed away to the south.  I stopped to savour the view for a while before assessing the lay of land.  Having decided the high point the Trimble was soon set up and gathering data. 

Gathering data at the summit of Trehafren Hill

Prior to visiting this hill I had analysed it with LIDAR and produced a height and position for both summit and bwlch.  The summit position produced by LIDAR although useful for my purpose on the hill was not necessarily all-important as even without its aid the high point of the hill was not difficult to pinpoint. 

LIDAR image of Trehafren Hill (SO 100 910)

I found the high point a metre or so from the narrow path that crosses this hill’s summit ridge in a west to east direction.  During data collection I stood to the east of the equipment and waited for allotted data to be gathered and stored. 

The Trimble GeoXH 6000 set-up position at the summit of Trehafren Hill

After closing the equipment down I took a number of photographs with the Trimble on top of my rucksack and breeze blown long grass surrounding it.  It proved a good summit to end the day’s hill bagging and surveying on. 

The Trimble GeoXH 6000 set-up position at the summit of Trehafren Hill

I arrived back at my car at 1.20pm, with in all seven hills visited and surveyed, six being P30s and one a P20 sub.  Six of the seven were new hills for me and all relatively local to where I live.  By the time I arrived home the temperature was soaring and I was glad of that early morning start! 

 

Survey Result: 

 

Trehafren Hill (significant name change)

Summit Height:  152.8m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SO 10020 91073 (Trimble GeoXH 6000)  

Bwlch Height:  115.4m (LIDAR)

Bwlch Grid Reference:  SO 10146 90923 (LIDAR)

Drop:  37.4m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  24.50% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

For details on the 2nd visit to this hill 

For further details please consult the Trimble Survey Spreadsheet