Llyn Alaw

Llyn Alaw is a shallow man-made reservoir on the Isle of Anglesey in North Wales. It was built in 1966 to supply drinking water to the northern half of the island at a rate of 35 million litres a day. The reservoir covers 3.6 square kilometres and is 4.3 kilometres long, making it the largest body of water on Anglesey. It was created by flooding the former marshland of Cors y Bol, which meant no homes or farms had to be lost. The lake reaches a maximum depth of 5.2 metres and is only a few metres deep in most places. The lake is a Site of Special Scientific Interest because of the large numbers of wildfowl that visit, especially in winter. Overwintering birds include Eurasian Teal, northern shoveler, whooper swan, mallard, wigeon, common goldeneye, common pochard, tufted duck and ruddy duck. Pink-footed geese also appear occasionally. The surrounding area is flat with marshy ground to the north, and the shore is bordered by vegetation, bushes and scrub. In summer, when water levels drop, mud flats appear along the edges. Visitors find a car park, three picnic sites and several miles of footpaths around the lake. The paths do not form a full circuit but lead to nature conservation facilities and way-marked walks. The lake has an active fishery with wild brown trout and stocked rainbow trout, making it one of Wales’s most productive lakes. Low islets dot the water, and the flat landscape offers wide views across the reservoir and its marshy surroundings.