Dwr Cymru is offering customers living in the vicinity of Llyn Celyn an opportunity to learn more about plans to upgrade the reservoir and dam.

To ensure all its dams continue to operate safely, the not-for-profit utility company has them regularly inspected by independent dam engineers.

Llyn Celyn was the subject of its 10 yearly independent inspection in 2019 using the latest and current guidance for reservoirs and dams in the UK.

While the report, published in 2020, identified no issues with the safety of the dam, it did make recommendations on some changes that would be required. These recommendations are statutory and are enforced by Natural Resources Wales. Welsh Water must also respond to them within a defined timescale.

Stephen Shakespeare, Dwr Cymru’s dam safety manager for North Wales said: “We take our responsibility for maintaining and operating our reservoirs and dams seriously at Welsh Water and the routine inspections we undertake help us achieve this.

“It is important to point out that the recent inspection of the dam at Llyn Celyn did not report any safety issues but as expected it made some recommendations to meet the latest guidance”.

One of the recommendations is to introduce measures to deal with any overspill that might occur at the reservoir during an exceptionally wet period that does not rely on manual intervention. At present, control is supported by a series of valves and pipework situated in the tower and the dam structure and is managed by staff on site. The dam already has one spillway, although the water at Llyn Celyn hasn’t risen to this level since the 1970s.

Stephen added: “We have considered numerous options to deal with an overspill for extreme water levels and will, in the coming months, submit a planning application to Snowdonia National Park Authority. The proposal is to build a new additional spillway to deal with exceptionally high water levels that could potentially happen in future.”

The proposed plans will see an upgrade to the reservoir and will ensure resilience for future generations.

To give the local community more information about the plans, Welsh Water has created an online exhibition (llyncelyn.com/) where people can visit a virtual room to view the proposed plans and find out more about the project.

The room will be open until 15 November.

If anyone cannot access the room, the team will also be visiting Frongoch Camp layby with the Welsh Water community van next Wednesday, 10 November.

The van will be there from 1pm-4pm and people will be able to put questions about the project to the team.

Ground investigations have already been carried out at the site, and formal discussions on the proposed spillway have started with Snowdonia National Park Authority. Depending on their responses it is anticipated that a full planning application will be submitted next summer in order that the work can be completed by the middle of 2025.