The Llyn Brenig Reservoir
penny beckett
At FOLAR’s 2020 annual symposium on the ‘Landscape of State Financed Industry’, Hal Moggridge spoke on the ‘Landscape of Reservoirs’, and mentioned Llyn Brenig reservoir in his talk. Penny Beckett sent FOLAR this blog report.
Last week, I went with friends to visit the northern part of Llyn Brenig, a large reservoir sited in a 15,000 ha area are known as Mynydd Hiraethog (Denbigh Moors), to the east of the Conwy Valley in North Wales.
View looking south with one of the circular stone cairns in the foreground
I was so full of the delights of joining friends in person again (rather than virtually) and to walk together in the Welsh countryside, on a warm and sunny day, that I quite failed to remember that the landscape planning and design of Llyn Brenig was described in some detail in Hal Moggridge’s book ‘Slow Growth On the Art of Landscape Architecture’ published in 2018. (1) I kicked myself that I hadn’t read Hal’s account before I made my visit to Llyn Brenig, as we might then have made more effort to see the landscape implementation at the southern end of this long reservoir. It is at this southern end where ‘a vast new landform has been introduced by the dam (50m high) retaining the reservoir.… with a crest 1.2km (0.75 miles) long’. As it was, the focus on our visit was the northern end of Llyn Brenig where we were content to explore the shoreline in a leisurely way, walk along the archaeological trail and eat a picnic on the crest of a hill looking out over the peaceful reservoir and the heather moorland beyond.
While looking online for further references to Llyn Brenig, I came across a short description written by John Gittins, who acted for the client during the contract period, about working with Colvin & Moggridge: ‘Most of my time was spent was spent with Hal Moggridge but from time to time Brenda [Colvin] came up to the site to observe and advise. To see her striding across the bleak Denbighshire moors in the driving rain was evidence of a strong individual who was still as committed to landscape at nearly 80 as she had ever been.’ It was agreed from the outset that local people should be involved in the planning of Llyn Brenig and Gittins goes on to explain that ‘Brenda Colvin and Hal Moggridge embraced the idea. The outcome reflected their vision and experience. It included the excavation of the Iron Age site, careful conservation of valuable flora, promotion of sustainable recreation activities around and on the reservoir and the participation of local people in its planning and management.’ (2)
View looking towards part of the Gors Maen Llwyd, a North Wales Wildlife Trust reserve which surrounds the northern end of Llyn Brenig
We were particularly lucky with the weather on the day we visited Llyn Brenig. As well as the account of when Brenda Colvin came to the site quoted above, Hal Moggridge refers in ‘Slow Growth’ to a visit in ‘dense fog’ and, on another occasion, to a ‘snowy December day’. The weather in these uplands can be fierce and in the detailed design of the reservoir, the northern shore edge needed protection from the waves that are driven up the reservoir by the strong winds that funnel through the valley. Certainly, when we visited there is evidence of erosion of both the northern shore edge and of the island built to act as a buffer against the force of the winds.
A windfarm has been constructed on the eastern edge of the northern end of Llyn Brenig. It sits on former forestry commission land but the scale of the landscape is such that the individual wind turbines (in my opinion, at least) do not detract from the overall scene. Indeed, they enhance it. The removal of conifers and the restoration of the heath has got to be a big improvement, both visually and ecologically. There is a pleasing sense of continuity to see 21st century structures taking their places alongside the Bronze age cairns that were conserved during the reservoir’s planning process.
Looking east at the windfarm on former forestry commission land now the responsibility of Natural Resources Wales. The boundary edge is clearly visible
At the time of our visit, Llyn Brenig was drawn down somewhat and the peaty soil profile on the edge near to the northern car park has eroded badly. There is also evidence of some invasive species at the shallow water’s edge which require ongoing management but otherwise the scheme as designed by Colvin & Moggridge and on the evidence of what we saw looking from the northern end of the reservoir is faring very well. It has become an integral part of the moorland landscape of Mynydd Hiraethog.
Erosion has exposed the peaty soil profile here
I look forward to visiting the landscape at the southern end of the reservoir soon and perhaps reporting on how that looks now almost 50 years on from its design and implementation.
Penny Beckett
August 2020
(1) ‘Slow Growth on the Art of Landscape Architecture’, Hal Moggridge, Unicorn Publishing Group, 2018.
(2) ‘Postcript to ‘How to be a landscape architect’, John W Gittins, extract from Landscape Research Group Extra 60 Nov 2011.
A video of Hal Moggride’s talk on ‘Landscape of Reservoirs’ and other speakers at FOLAR’s ‘Landscape of State Finance Industry’ will be available shortly at https://www.folar.uk/events
Brenda Colvin (1897-1981) became the first female President of the Institute of Landscape Architects (now Landscape Institute) in 1951, the year of the Festival of Britain. The Brenda Colvin archive, part of the Landscape Institute archive, is held at the MERL, Reading.
Fact File: Llyn Brenig
Llyn Brenig is known as an upland, reserve reservoir, located on Mynydd Hiraethog (the Denbigh Moors), which lie between Ruthin (to the east) and the eastern boundary of the Snowdonia National Park. The water body is sizeable: 3.8km long and about 1.8km wide. There is a visitor centre on the western shore, accessible from the A5 at Cerrigydrudion via the B5401.
Llyn Brenig is one of four reservoirs feeding into the River Dee, which takes water on to Chester and beyond. But when Llyn Brenig was constructed (the last of the four) it took three years for the reservoir to fill. This is because Llyn Brenig is only fed by inflowing streams from its surrounding catchment area. The reservoir was only ever intended to top up supply and maintain the flow into the River Dee if the other reservoirs, for whatever reasons, haven’t enough stored water to do so. Thus the title ‘reserve’ reservoir.
The reservoir was commissioned in 1970 by the Dee & Clwyd River Authority (now part of the not-for-profit Dŵr Cymru or Welsh Water Authority) and completed in 1976.
Landscape architects: Colvin & Moggridge, led by Hal Moggridge.
Grid Reference: SH983 573