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A Walk Around the Grwyne Fawr Reservoir

A 4-hour circular walking route around the Grwyne Fawr Reservoir in the Brecon Beacons.

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A walk around the Grwyne Fawr Reservoir

Despite living here for over 14 years I had never been up close to the Grwyne Fawr reservoir, I had only ever seen it from a distance from the tops of the Black Mountains. I was spurred into action when my friend Danny appeared on a rainy Wednesday from Bristol to go for a walk. Time to go and have a look at the dam I thought.

Getting to Grwyne Fawr Reservoir

The Grwyne Fawr Reservoir is a huge piece of engineering completed in 1928 with the purpose of supplying clean water to the South Wales valleys. There was quite a large temporary village established for the workforce when work started in 1912 and remains of buildings still surround the site. At one stage over a thousand people lived up here and some labourers made the eight-mile trip to Talgarth daily on foot.

The route is a simple one. Drive up to the car park at SO 252 285 – a lovely 12-mile drive from Gliffaes Country House Hotel.

grwyne fawr reservoir

Route around the reservoir

Walk along the rough landrover track up to the top of the dam wall, a distance of about two miles which parallels the tarmac road to the base of the dam. The past few days have been very wet, meaning a good deal of water was cascading over the top of the dam and made an impressive sight. Take time to explore at the top of the dam – you can walk across the top to have a look down over the edge. (This is the site where Princes William & Harry were caught making an ‘unauthorised’ abseil in 1998 while under the charge of their nanny, Tiggy Legge-Bourke!)

Follow the path past the reservoir and up the valley NNE all the time following the line of the stream that feeds the reservoir. At the head of the reservoir is a small mountain bothy maintained by the Mountain Bothy Association, not easily seen from the path. The path can be wet and is almost a small stream in itself during wet weather. After crossing the stream you come out on top of the ridge in the area of the path junction at SO 204 327.

Head SSE on the opposite side of the valley to which you came up on top of the ridge towards the peak Waun Fach (the highest point in the Black Mountains). Be warned it is VERY boggy around Waun Fach and is best avoided by staying off the ridge and following your nose about 500 hundred meters below the ridge (along the 750m contour). The countryside up here is bleak and wet and all we saw was a pair of grouse.

Directions back to the car park

When you reach the northern edge of the Mynydd Du forest follow the spur west downhill back towards the road and the stream. Once at the bottom of the hill where the corner of the wood meets the stream (SO 247 291) cross the small stream to your right and follow the Grwynwe Fawr river through the woods for a short distance until you come to a footbridge enabling you to cross the river to get back on to the metalled road and back to your car.

This route took us just over 4 hours but we went pretty slowly and spent around 40 minutes at the dam wall.

If you want to do this walk whilst staying at Gliffaes, we will be happy to mark up your map for you and send you on your way with a packed lunch.

Book your Brecon Beacons escape

Gliffaes Country House Hotel is nestled in the heart of the Brecon Beacons National Park. We’ve created a useful guide of local attractions and activities here, containing information on walks, things to do, local shopping and places to visit, which you can use to help map out your visit to the Brecon Beacons.

If you’re looking for a place to enjoy a fresh, locally-sourced lunch, dinner or afternoon tea, or somewhere comfortable to stay the night, our friendly country house hotel is the perfect base for your Brecon Beacons break.

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