earth embankments to hold back the water. In 1889, shortly after completion, the lake was stocked with 400,000 Loch Leven trout. Between 1881 and 1892 the aqueducts carrying water to Liverpool were constructed. Construction of the dam flooded the village of Llanwddyn. The residents of the village were not consulted about the proposal for a dam and opposed the plan. Their relocation involved the demolition of a church, two chapels, three inns, ten farmhouses, and 37 houses. A new settlement to house them was built lower down the valley by Liverpool Corporation. Description The Vyrnwy dam is high from the bottom of the valley, and thick at the base; it is long and has a road bridge running along the top. It is decorated with 31 arches each spanning and two small towers each with four corner turrets rising above the road surface. The dam was the first to be constructed with drainage tunnels designed to prevent a build up of pressure beneath the base. It is listed as a Grade I historic building by Cadw. The dam was the first to carry water over its crest instead of in a channel at the side. At the bottom of the dam is a body of water known as a stilling basin necessary to absorb the energy when the water flows over the crest and into the valley, and to stop the water eroding the foundations of the dam. A power house located under the west tower contains an electrical generator driven by water leaving the reservoir. Before mains electricity arrived in the 1960s this was the area's only source of power. About from the dam is the reservoir's straining tower. Standing only from the shore, its purpose is to filter or strain out material in the water with a fine metal mesh, before the water flows along the aqueduct to Liverpool. Its architecture represents Gothic revival, built at the same time as the dam. The tower as a whole is tall, of which is above top water level, and is topped with a pointed copper-clad roof, coloured light green. The west and east towers release compensation water into the River Vyrnwy through huge valves; the river would dry up unless a minimum flow was maintained. Depending on the levels downstream, the reservoir can release from of compensation water daily. The flow is measured by Natural Resources Wales at a weir