We have been working, with a coalition of environmental groups, to prevent the construction of hydroelectric dam on the Afon Cynfal in the Eryri National Park, primarily because of the threat we feel it poses to wildlife.
The coalition was dismayed that, on 15 July 2026, the Eryri National Park Authority issued a notice to grant planning permission for the scheme.
In response, we are supporting an application by Cymdeithas Eryri (Snowdonia Society) for a Judicial Review that would consider whether the law has been correctly followed with regard to this planning decision. We are also supporting an appeal to raise funds to cover the associated legal costs, estimated to be over £60,000.
This scheme would, at times, divert up to 70% of the water away from the iconic Rhaeadr y Cwm Waterfall, located in the Cwm Cynfal Site of Special Scientific Interest (SSSI), which forms part of the wider Migneint–Arenig–Dduallt Special Area of Conservation (SAC) and Special Protection Area (SPA): an internationally important area for blanket bog and upland heath. The change in hydrology that would result from the scheme could seriously threaten the rare mosses and liverworts that are a precious feature of the site. A similar scheme in Afon Cwm Llechen, just 21 miles away, saw four of five species undergo a decline of up to 43% over a ten-year period.
Graeme Cotterill, Director of Cymdeithas Eryri, said:
“Taking this step is unprecedented for Cymdeithas Eryri. In our 60-year history, we have engaged with countless Eryri National Park Authority planning decisions – but this is the first time we’ve legally challenged one. Whilst our close working relationship with the Authority in recent years benefits everybody and we intend it to continue, it is important that we challenge decisions that we and our supporters feel are not made in the Park’s best interest.”