Llyn Brenig

Llyn Brenig is a reservoir located in Wales, in the heart of the Denbigh Moors, at a height of 1200 feet, on the border between the counties of Conwy and Denbighshire. It is used to manage the flow in the River Dee as part of the River Dee regulation system which is designed to protect the water supply for North West England and north-east Wales, particularly Liverpool and its surrounding area. Construction and operationConstruction began in 1973 and was completed in 1976. It has a capacity of 60 million m³ and was first filled in 1979. With a surface area of around 920acre, it is the fourth largest lake in Wales, behind Llyn Tegid (Bala Lake), Llyn Trawsfynydd and Lake Vyrnwy. The lake has a perimeter of some 9mi. The catchment of the reservoir is very significantly over-reservoired. This means that the reservoir cannot fill from its own catchment within one annual hydrological cycle. When the reservoir level is drawn down, it can take several years for it to completely re-fill again. Llyn Brenig is therefore only used during drought conditions when the capacity of Llyn Celyn and Llyn Tegid are no longer predicted to be capable of maintaining the flow in the River Dee.

Llyn Brenig is a reservoir located in Wales, in the heart of the Denbigh Moors, at a height of 1200 feet, on the border between the counties of Conwy and Denbighshire. It is used to manage the flow in the River Dee as part of the River Dee regulation system which is designed to protect the water supply for North West England and north-east Wales, particularly Liverpool and its surrounding area. Construction and operationConstruction began in 1973 and was completed in 1976. It has a capacity of 60 million m³ and was first filled in 1979. With a surface area of around 920acre, it is the fourth largest lake in Wales, behind Llyn Tegid (Bala Lake), Llyn Trawsfynydd and Lake Vyrnwy. The lake has a perimeter of some 9mi. The catchment of the reservoir is very significantly over-reservoired. This means that the reservoir cannot fill from its own catchment within one annual hydrological cycle. When the reservoir level is drawn down, it can take several years for it to completely re-fill again. Llyn Brenig is therefore only used during drought conditions when the capacity of Llyn Celyn and Llyn Tegid are no longer predicted to be capable of maintaining the flow in the River Dee.