Mapping Mountains – Trimble Surveys – Mynydd Hiraethog

22.08.14  Castell Dinbych (SJ 051 657)

Castell Dinbych (SJ 051 657)

Standing aloof above the small town of Dinbych (Denbigh) is a past stronghold of Edward 1’s campaign to pacify Wales.  This construction is Castell Dinbych (Denbigh Castle) which is now a ruin managed by Cadw; the Welsh heritage agency.  The site on which the remains of the castle are situated is impressive and also imposing as it looks down on the fertile plain of the Vale of Clwyd.

The first recorded stronghold on this site was Welsh and originally belonged to Llywelyn the Great, it was later held by Dafydd ap Gruffydd the brother of Llywelyn ap Gruffudd; the last Welsh Prince.  Once Edward had visited his rebellious neighbours the Welsh construct was torn down and supplanted with a new English fortress, the remains of which are on display looking out over Dyffryn Clwyd and Dinbych.

I’d wanted to visit this castle ever since first listing it in the Sub-List that made up the Welsh 100m P30 list that is published on Geoff Crowder’s website (to see the original list click {here}).  Soon after publication I added drop values to each of the 100m height band lists that appear on Geoff’s website, and based on bwlch contouring between c 100m – c 110m I’d estimated the height of the bwlch as c 113m, and as the hill that the castle sits on has a summit spot height of 143m, these values gave the hill c 30m of drop.  Since adding the drop values the Ordnance Survey have made public a rather helpful map that is published on the Geograph website, this map gives bwlch contouring between c 110m – c 115m, with the valley to valley contours being relatively close together, giving an estimated bwlch height of c 111m, giving a drop of c 32m.  It would also be a bit of fun trying to survey the top of a castle as well as trying to find the critical bwlch as it seemed to be placed in someone’s house on a road named Bryn Stanley.

I parked at the top of Love Lane, adjacent to the entrance to Castle Lane, and walked up the latter to the castle entrance, passing the castle walls and part of the foundation rock that it sits upon.  The entrance is through the remains of the three towered main gateway which is an imposing edifice to greet the visitor, Edward certainly knew how to impress through sublegation as his Welsh fortifications testify.

Once inside there is a modern construct with a ticket counter, entrance is £3.50 for adults.  People were sitting enjoying a coffee and looking out over the castle grounds, there are informative leaflets and books for sale, and a helpful artist’s impression on the wall of what the Castle once looked like.  I approached John Sherlock who is the Lead Custodian at the Castle and explained the purpose for my visit, John was soon offay with all details concerning Trimbles, hill lists and the finer detail of drop.  He kindly showed me the entrance door to the castle grounds and let me in for free, I thanked him and asked if the castle is closed outside of opening times, it seems it is not, therefore it seems entrance is free after 5.00pm as he informed me the castle never closes.

Artist's impression of how Castell Dinbych looked

Once in the grounds I headed toward the high point, which is relatively obvious to find and placed the Trimble on the neatly cropped grass near to high stone walls that make up part of the castle’s northern perimeter. 

As data were logged the sun shone and a few people roamed the lower parts of the castle, thankfully no one came near to the high point until ten minutes of data were collected, and even then the family who were walking their young child around the ruins did not approach the high point until the Trimble was closed off.

Gathering data at the high point of Castell Dinbych

Although bagging hills and doing surveys takes you to places that otherwise one wouldn’t visit, I felt that my brief sojourn to Castell Dinbych did not take in a full cultural experience, but as I had a 5.30pm rendezvous with Mark in Morrisons café I could not linger, and I still had to visit the bwlch.

Before leaving I visited John Sherlock and thanked him and walked back to the car and drove to Morrisons, and then walked back up the road toward Bryn Stanley and the area of this hill’s bwlch.  This I found at the end of the road that forms Bryn Stanley, next to a gravel turning area that gives access to a footpath heading in to a field to the south.

I considered setting the Trimble up on the gravelled area but the thought of having it run over for a second time did not seem prudent, so I had a good look at the area and decided that the critical bwlch was probably in or near to someone’s bungalow.  I picked which living room I thought the critical bwlch was situated in and knocked on the accompanying front door, I soon had permission to set the Trimble up on their garden fence adjacent to the road.

The southern view with the Trimble gathering data on the corner of the fence

The northern view with the Trimble gathering data at the critical bwlch of Castell Dinbych

I placed the Trimble on the draughts board which was used to create a flat surface on top of two adjacent fence post tops and measured the offset down to the road.  This still wasn’t ideal as cars could easily knock the Trimble off its perch if they turned in to the gravelled area and touched the slightly overhanging draughts board.  I kept a close eye on it and only asked one car to move on as it had stopped almost in front of it, with engine running for the occupant to make a mobile phone call.  Once ten minutes of data had been gathered I packed it away and walked back to Morrisons car park and awaited the arrival of Mr Trengove.

   

Survey Result:

Castell Dinbych

Summit Height:  143.2m (converted to OSGM15)  

Summit Grid Reference:  SJ 05168 65796

Bwlch Height:  110.2m (converted to OSGM15)

Bwlch Grid Reference:  SJ 04697 65704

Drop:  33.0m  (100m Sub-Twmpau reclassified to 100m Twmpau)

Dominance:  23.04%

For further details please consult the Trimble survey spreadsheet click {here}