|Sites of Special Scientific Interest||12|
|Maintained by||Elan Valley Trust and Dŵr Cymru|
You can see the dams and reservoirs in any sequence; however, this guide will recommend them in the following order:
The following map details all car parks, dam locations, and additional points of interest including our favourite picnic spot.
How long does it take to see the dams and reservoir?
You will require a car or coach to see all the dams and reservoirs in one day. If you are planning to walk the valley, accommodation is recommended, there are plenty of options in and near the valley.
It will take you roughly five hours to see every dam, have a picnic, and pop into the visitors centre. Bear in mind, there is plenty of driving between each dam so it’s best to arrive at the valley early in the morning.
If you are planning to visit during the winter, you’ll need to arrive at sunrise to make the most of limited daylight.
If you plan to arrive as a group, expect more time required to see the dams and reservoirs.
When is the visitor centre open?
The centre is open every day between 9 am – 5 pm; however, this may be affected by coronavirus restrictions or the seasons. Always check you can travel before you leave.
Is the Elan Valley suitable for a picnic?
There are plenty of spots to picnic. Our favourite would be next to the Pont Ar Elan bridge at the top of the Craig Goch reservoir. There are picnic benches overlooking the Elan river and the view of the valley can only be described as sublime.
It’s probably best to avoid picnicking near the dams because the falling water sprays into the air when they are flowing.
How do I get to the Elan Valley?
If you are arriving by public transport, head for Rhayader. The town no longer has a railway station; however, you can catch a train to Llandrindod Wells and then take a 30 min bus journey to Rhayader. There are bus services from Rhayader to Elan Village, which is where the visitors centre is located. Check out Traveline Cymru for travel info. You can always catch a taxi from Rhayader or Llandrindod Wells as an alternative option.
If you are visiting by car or coach, head straight for the visitors centre where you will be required to pay a parking charge.
How much is parking and how is payment accepted?
A parking charge of £3.00 covers your car for the whole day at every car park in the estate.
Visitors by car can pay by cash or card at the visitor centre or via the machines by credit/debit card. Parking may also be booked and paid for on a mobile device using the NexusPay-GroupNexus app (downloadable via QR codes on site)
Season tickets for car parking are also available, costing £35 for twelve months, please ask at the information desk.
Where are the toilets?
- Visitors centre
- Craig Goch car park
- Claerwen car park
- Penbont House near the Pen-y-Garreg car park
The dams and reservoirs
Ready to explore? Let’s begin!
Caban Coch dam and reservoir
The Caban Coch (Welsh for ‘Red Cabin’) is the lowest out of all the dams. It was constructed to hold back water, which is used to balance the River Wye via the Elan River, which is a tributary. Therefore, the water in the Caban Coch reservoir is not used for the supply to Birmingham .
27 million gallons of water joins the River Wye daily. Before the water reaches the river, it passes through two powerhouses, one on each bank of the Elan River. They contain hydro-electric turbines, which provides power for the Elan waterworks .
You can easily park in the adjacent car park on the northern bank of the dam. Here you’ll see the landscape scars left over from the Craig Gigfran quarry, which was one of two that supplied local stone for construction.
There’s a viewing platform next to the car park that offers a superb view of the water flowing over the dam (unless you are visiting during the dry season). You’ll see a pathway leading down to an arched bridge below that connects the two powerhouses. This is a great spot to enjoy the falling water and snap some awesome photos. Be mindful to wear a waterproof because of the spray from the dam.
|Resident engineer||George Yourdi|
|Dam height||122 ft (37.2 m)|
|Dam length||566 ft (172.5 m)|
|Dam base thickness||122.5 ft (37.3 m)|
|Dam listed status||Grade II*|
|Total electricity capacity||1,070 kW|
|Total reservoir capacity||7,815,000,000 gallons (35,530 megalitres)|
|Top water area||500 acres (2 km2)|
Caban Coch is a masonry dam with heavily rock-faced blocks. There are spillways with walls, which broaden as they drop and curve to become parallel with the river. When the dam is not flowing, you can see two rows of protruding blocks that were used to support scaffolding during construction. At the bottom of the dam, there are two circular outlets with a keyblock set in surrounds with piers to each end and a pyramidal pediment with tumbled blocks. Each end of the dam contains a platform with gigantic capstones worked to resemble natural rock .
Garreg-Ddu dam and reservoir
This Garreg-Ddu reservoir (Welsh for ‘White Rock’) is where water enters the Elan Valley Aqueduct via the Foel Tower, which directs it to filter beds before journeying on to Birmingham. The chief engineer James Mansergh realised water would be a problem in the summer months . If the level dropped too low, water would not be able to enter the tower and so the Garreg-Ddu Dam was constructed to maintain a minimum water level of 40 feet below the top level.
As a result, the dam is submerged when the water rises above. This is the reason why such a tall viaduct was constructed on top of the dam. The entire structure can be seen when the reservoir is low as shown in this photo.
In times of low water during the summer, the reservoir can be topped up from the Pen-y-Garreg and Craig Goch reservoirs upstream. There is also a tunnel next to the Dol-y-Mynach dam that directs water from the Claerwen Valley into the Garreg-Ddu .
The car park is located on the south-western bank of the dam. Follow the south-east road and you’ll find a path leading up to the Nantgwyllt Church, which was built to replace an original that was flooded by the reservoir. The view from the church is stunning and a great place to photo the dam and Foel Tower in the distance. You may wish to visit the church if it’s open. It features the bell and lanterns from the original church before it was demolished to make way for the reservoir.
Walk across the dam for more beautiful views of the valley. You can then head across to see the Foel Tower, be mindful of vehicles when walking the roads.
|Resident engineer||Herbert Jefcoate Atkinson|
|Total height||123 ft (37.5 m)|
|Dam length||417 ft (127.1 m)|
|Dam listed status||Grade II*|
|Total reservoir capacity||1,320,000,000 gallons (6,000 megalitres)|
Please note the dimensions above were taken from an unofficial source as we have yet to find verified information.
Garreg-Ddu consists of a rock-faced brown stone viaduct resting on a submerged dam. There are five narrow arches to the north-east and seven broader elliptical arches in the centre. The parapet consists of large rock-hewn capstones to each end .
Pen-y-Garreg dam and reservoir
This dam is named after the nearby Pen-y-Garreg farm (Welsh for ‘Above the Stone’), which lost some of its lands to the reservoir after initial flooding . The dam is unique in that its valve tower is located in the centre.
The car park is a ten-minute walk from the dam next to an arched bridge near Penbont House. Walk along the river to the base of the dam where you will get a magnificent view of the dam outlet close-up and hear the roaring thunder of water as it gushes down. There are steps to the left, which will take you up to the viewing platform south of the dam.
|Resident engineer||Eustace Tickell|
|Dam height||123 ft (37.5 m)|
|Dam length||528 ft (160.9 m)|
|Dam base thickness||115 ft (35.1 m)|
|Dam listed status||Grade II*|
|Total electricity capacity||810 kW|
|Total reservoir capacity||1,332,000,000 gallons (6,055 megalitres)|
|Top water area||124 acres (0.5 km2)|
The dam wall and spillway of Pen-y-Garreg is very similar to Caban Coch. There are some differences, for example, at the bottom of the dam, there is only one circular outlet with a key block set in an aedicule-like surround with piers to each end and a pediment. There are also platforms at each end of the dam with steps leading down to the river. At the centre of the dam is an octagonal valve tower with a copper dome containing waterspouts around its circumference. The dome is adorned with a lantern and fish weathervane. The interior is said to contain original operating machinery .
Craig Goch dam and reservoir
Craig Goch (Welsh for ‘Red Rock’) is the highest reservoir in the Elan Valley. The curved dam is arguably the most beautiful and it featured in the Welsh police detective drama Hinterland.
Park up on the east side of the dam then walk across to enjoy the detail of its valve tower, the ornate arched viaduct, and the stunning views of the Elan Valley in all its glory. Be mindful of vehicles when crossing the dam and use the refuges where possible.
You can also walk past the gate and follow the road down to the river at the bottom for a close-up view of the dam. There are toilets next to the car park.
|Resident engineer||George Yourdi|
|Dam height||120 ft (36.6 m)|
|Dam length||513 ft (156.4 m)|
|Dam base thickness||104 ft (31.7 m)|
|Dam listed status||Grade II*|
|Total electricity capacity||480 kW|
|Total reservoir capacity||2,028,000,000 gallons (9,219 megalitres)|
|Top water area||217 acres (0.9 km2)|
Craig Goch is a curved masonry dam with heavily rock-faced blocks. The spillways are similar to those on the Caban Coch and Pen-y-Garreg dams. The Craig Goch supports a viaduct on 13 arches that carry the roadway. The viaduct features contrasting rock-faced and smoother stone with piers supporting segmental arches containing keystones and a parapet with coping and heavy rock-faced capstones. There is a band course at road level and polygonal refuges three arches from each end. The dam also has an attached polygonal valve tower very much like the Pen-y-Garreg .
Dol-y-Mynach dam and reservoir
The Doly-y-Mynach is the first of three dams that were proposed by the chief engineer James Mansergh as the second phase of his Elan Valley development plan. He proposed the damming of the Claerwen Valley to expand the supply of water to meet the predicted growth of consumers.
The dam’s foundations had to be constructed before it was prone to be submerged by the flooding of the Caban Coch reservoir. The Doly-y-Mynach was due to be completed following the completion of the Elan Valley reservoir; however, it never came to pass. Today, the dam remains as it was left in 1904 and it is referred to as the ‘unfinished dam’.
Unlike the other dams, the Doly-y-Mynach does not have dedicated car parking. It is the least accessible out of all the dams and requires a 10-minute trek through woodland to reach. There are two spots to park near the access gate, refer to our map at the top for more info.
Once you enter the gate, follow the path down to the reservoir bank, you’ll end up walking past the Doly-y-Mynach tower, which controls the flow of water into a tunnel that feeds into the Garreg-Ddu reservoir to the north. The Doly-y-Mynach cannot be crossed by foot and is unique because it offers visitors a view of its core in between the outer faces of masonry .
|Resident engineer||George Yourdi|
|Intended dam height||101 ft (30.8 m)|
|Intended dam length||938 ft (285.9 m)|
|Intended total reservoir capacity||1,640,000,000 gallons (7,455 megalitres)|
|Intended top water area||148 acres (0.6 km2)|
|Actual top water area||26 acres (0.1 km2)|
Claerwen dam and reservoir
The Claerwen Reservoir is located in the Claerwen Valley, west of the Elan Valley. Although it is technically in a separate location, the reservoir and its dam are commonly referred to as part of the Elan Valley and they are the largest and most modern structures in the estate.
The Claerwen dam was the eventual solution to the second phase of development proposed by the Elan Valley chief engineer James Mansergh. He originally proposed a series of three dams be constructed along the Claerwen Valley following the completion of the initial three dams in the Elan Valley . The unfinished Dol-y-Mynach dam is the only legacy of this proposed second phase.
The second phase never materialised, and the Claerwen River ran unobstructed until fresh concerns over the supply of water were raised following a severe drought in 1937. By 1939, proposals had been submitted to replace the original three dams with one larger dam, an option made possible due to advances in civil engineering and technology. Construction was halted due to production constraints as a result of World War Two, and the dam was finally opened in 1952 by Queen Elizabeth II as one of her first official appearances as the new British monarch .
The dam was famously climbed by Richard Hammond in a classic Land Rover on Top Gear.
Park up in the car park at the foot of the dam. Here you can take in the sights of the Claerwen Valley and walk along the river. Afterwards, drive or walk up to the top of the dam. If driving, you’ll need to head back down the road you came from and turn left at the first junction, which will take you to a small car park next to the top of the dam.
The view from the top is stunning, especially when the dam in flowing. Walk across the dam to the central viewing platform where you can witness the sheer scale of this structure and the reservoir. Continue walking to the western viewing platform, where you will experience the best views of the valley.
|Engineer||Sir William Halcrow & Partners|
|Dam height||184 ft (56.9 m)|
|Dam length||1,166 ft (355.4 m)|
|Dam listed status||Grade II|
|Total electricity capacity||1,680 kW|
|Total reservoir capacity||10,625,000,000 gallons (48,302 megalitres)|
|Top water area||650 acres (2.6 km2)|
Claerwen is a concrete dam with a masonry face so it blends in with the historical look of the other dams. Claerwen supports a viaduct that carries the roadway on 13 elliptical arches with stone parapets. The central arch is broader to support the viewing platform, which features a balustrade.
The end piers of the platform run down the full height of the dam framing a stepped spillway. At foot of this, there are two buttresses with doorways that are linked by bridges over a pool. There are stepped spillways with parapet walls at each end of the dam. The spillways broaden as they drop and their walls turn to frame the channel at the foot of the dam, which is spanned by a stone bridge of two segmental arches with iron railings .
Foel Valve Tower
This tower controls the flow of water into the Foel Tunnel, which leads to the nearby treatment works before entering the Elan Aqueduct on its journey to Birmingham. The tower is a Grade II* listed structure and contains a 300 kilowatt hydroelectric turbine.
This round valve tower was constructed using brown rock-faced stone. The upper stage has a copper dome with a weathervane, seven round-arched windows, and a doorway onto a bridge connecting the tower to land.
The bridge has an elliptical arch and parapet, which continues round the broader lower stage of the tower. The lower part of the tower, which is submerged when the reservoir is full contains two tiers of barred round-headed intake windows. The interior is said to contain original operating machinery .
- David Lewis Brown – The Elan Valley Clearance
- Rita Morton – The Building of the Elan Valley Dams
- Elan Valley Trust Website – The 6 Dams
- CADW – 16202 – Caban Coch Dam
- CADW – 16200 – Carreg Ddu Viaduct and Submerged Dam
- CADW – 16199 – Penygarreg Dam & Valve Tower
- CADW – 16198 – Craig Coch Dam & Valve Tower
- Coflein – Dol-y-Mynach Reservoir, Elan Valley Water Scheme
- CADW – 16222 – Claerwen Dam, including attached footbridges
- CADW – 16201 – Foel Valve Tower