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Plans submitted for major works programme at Llyn Celyn

02 Nov 2022 3 minute read
Llyn Celyn. Photo Dŵr Cymru

Dŵr Cymru has submitted plans to Snowdonia National Park Authority for a major works programme  to be carried out at Llyn Celyn reservoir near Bala.

The application includes plans for a new spillway to help deal with potentially high levels of water and  also includes proposals for improvements and extra visitor facilities at the reservoir’s main car park.

Llyn Celyn reservoir was opened in 1965 following the controversial flooding of the village of Capel Celyn to create the dam to supply water to Liverpool and parts of the Wirral peninsula.

Liverpool Corporation gained approval for its plans from Westminster in 1957 and against the wishes of most Welsh Members of Parliament and without the consent of Welsh authorities.

Today Llyn Celyn is owned by Dŵr Cymru and managed on behalf of Natural Resources Wales (NRW). The release of the water from Llyn Celyn is regulated by NRW and the Dee Operating Agreement.


Andrew Bowen, Head of Dam Safety at Welsh Water said; “Welsh Water takes its responsibility for dam safety very seriously.

“As with all large reservoirs, Llyn Celyn is subject to a number of regular inspections.

“The 10 yearly inspection by an independent engineer carried out in 2019 stated that Llyn Celyn is in good condition but made some recommendations for upgrading the site. These recommendations are mandatory and must be implemented within 5 years.”

One of the recommendations was to find a solution to deal with extremely high water levels to minimise manual intervention.

There is currently one spillway at Llyn Celyn located within the reservoir, and this will remain.

Welsh Water now plan to build an additional spillway near the crest of the dam close to the main car park.

The plan to build an additional spillway has been shared with the local community over the past 12 months in public events and via an online exhibition and a pre-application consultation was also carried out over the Summer.

Llyn Celyn Plans

Andrew Bowen, Head of Dam Safety at Welsh Water added; “As Llyn Celyn lies within Snowdonia National Park, the visual impact of the new spillway has been a priority for us.

“The new spillway has been carefully designed to blend in with its natural surroundings and work with the land adjacent to the dam.

“As part of this work, we are also keen to carry out improvements for those who visit the dam. New picnic tables, bike racks and information boards explaining the history of the reservoir have been included as part of the planning application.”

The water that flows from Llyn Celyn is used for a variety of purposes and by various stakeholders including a hydro powerhouse on site to create electricity for the National Grid, supply water to Canolfan Tryweryn, support local fishing, manage water levels in the River Dee and to supply water to Welsh Water, United Utilities, Hafren Dyfrdwy, Severn Trent and the Canal and Rivers Trust.

Following the submission of the application events have been organised for the local community to see the detailed plans.

There will be two events in November at Frongoch and Bala where the public can see the plans and discuss them with the project team. They can also see details on

The proposed work follows a 12-month restoration project on Capel Celyn Memorial Chapel by Welsh Water which was completed last year to help preserve the Grade 2* listed building.

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1 year ago

Cofiwch Dryweryn. Never Forget.

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