Environmental campaigners in Eryri (Snowdonia) are warning that one of the National Park’s most iconic waterfalls, Rhaeadr y Cwm above Llan Ffestiniog is under threat from a hydro power scheme that would see, at times, nearly 70% of the water diverted out of the waterfall into a plastic pipe. The concern is that this will significantly affect the appearance and thunderous sound of the waterfall, as well as fundamentally changing the environmental conditions. The gorge is part of a Site of Special Scientific Interest (SSSI), designated because of the vulnerable species that can be found there, including rare damp-loving plants. It can be accessed on foot by an ancient trackway, as part of the Snowdonia Slate Trail and first impressions don’t disappoint.

After the Welsh Senedd declared a Nature Emergency in 2021, the Welsh Government strengthened Planning Policy in Wales² to make clear that there must be no development in Sites of Special Scientific Interest (SSSIs) except in ‘wholly exceptional circumstances’. It also spelt out that this would only be acceptable where there is an agreed position in the development plan indicating this. However, the National Park has interpreted this to mean that, if the development is for renewable energy, then that makes it ‘wholly exceptional’ and it can therefore go ahead. This could set a damaging precedent for SSSIs across Wales.

The plan has run into huge opposition both locally and more widely across the country. At least 1,136 people have formally objected to the plan. That is a huge number of people to object to a single planning application³.

A coalition of five environmental groups is working together to oppose this plan: North Wales Wildlife Trust, Save our Rivers, Cymdeithas Eryri Snowdonia Society, Buglife, Noth Wales Rivers Trust, Plantlife and the British Mountaineering Council. Together, these groups are writing to the Welsh Government, calling for plan to be ‘called in’, so it can be determined by Welsh Ministers in line with policy.

Jane Barbrook, Vice Chair of Cymdeithas Eryri says: “There seems to be a shortfall here. You can protect an ancient tree or an historic house, but you don’t seem to be able to protect a waterfall, in terms of its visible attributes and its sound.”

Rory Francis from Cymdeithas Eryri Snowdonia Society adds: “The huge irony here is that an iconic waterfall and one of Wales’ prime wildlife sites is being threatened for a really rather trivial amount of renewable energy. The capacity of the scheme is just 600kW. That means you would need no less than 12 schemes like this to generate as much power as a single modern onshore wind turbine, like those proposed at Y Bryn, between Maesteg and Port Talbot, each of which would be 7.2MW. Yes, we need to move to net zero, but in doing so, we should follow planning guidelines and protect our most precious wildlife sites and landscapes.”

1. The Officer’s Report to the Planning and Access Committee is available online here: https://eryri.gov.wales/wp-content/uploads/2026/01/Planning-and-Access-Committee-21.01.26-website.pdf
2. Planning Policy Wales is available online here: https://www.gov.wales/sites/default/files/publications/2024-07/planning-policy-wales-edition-12.pdf The relevant paragraphs are 6.4.26 and 6.4.27
3. The Officer’s report actually gives the figure of 453, however, the coalition against the plan is aware that 1,135 people formally objected through their campaign website. They have passed these names and addresses and the full text of the actual letters they sent to the National Park Authority, which has agreed to count these as objections and to update the Committee on Wednesday. We do not know the cause of this failure. It may involve an inbox filling up or a spam filter. The coalition was able to pass this list of names and addresses to the National Park Authority, under GDPR rules, as all the individuals concerned had already consented to these going to the that body.