Plaques marking the three stages of construction of the Vyrnwy Reservoir. Lake Vyrnwy (Llyn Efyrnwy) is a reservoir constructed in the 1880s for Liverpool Corporation Waterworks to supply Liverpool with fresh water. It flooded the head of the Vyrnwy valley and submerged the village of Llanwddyn. The Lake Vyrnwy Nature Reserve and Estate that surrounds the lake is jointly managed by the Royal Society for the Protection of Birds (RSPB) and Hafren Dyfrdwy. When the reservoir is full, it is 26 metres (84 ft) deep, contains 59.7 gigalitres, and covers an area of 4.54 square kilometres (1,121 acres), the lake has a perimeter of 19 kilometres (12 mi) with a road that goes all the way around it. Its length is 7.64 kilometres (4.75 mi).
