The Victorian engraving on the right shows the entrance to the Hirnant tunnel. This carries the water from Lake Vyrnwy to the 70 mile long aqueduct to Liverpool. The workman standing inside gives a good idea of the size of the tunnel.

There is a very impressive pointed tower which rises out of the waters of Lake Vyrnwy some distance from the dam. It looks like part of a fairytale castle, and it is linked to the shore by an arched bridge.
This is the 'straining tower', which is where the water leaves the lake at the start of a journey along an aqueduct and pipeline to Liverpool, around 70 miles away. It is called a straining tower because the water first passes through a fine metal mesh to filter or strain out material in the water. The tower stands in over 15m (50ft) deep water and is over 48m (160ft) high, so much of the structure is hidden underwater. You can see the base of the tower in the picture below right.