This beautiful dam was actually only created in the 1970s and is Wales’ second-biggest reservoir by water volume, and South Wales’ biggest. It supplies water to Swansea, parts of Cardiff and the South Wales Valleys.
It’s named after a stream called Nant y Bryniau which means “Stream in the Hills”. Apparently a map maker misspelt the word Bryniau and so the name was Llyn Brianne. Had it been spelt correctly, Llyn Bryniau would probably have been a more fitting name - “Lake of the Hills”.
There is a rumour that a village was flooded to create the dam, however, it was only one farm - Fanog, which was lost but it had already been abandoned years before. When the water is low, the old buildings can be seen.
There are reminders of the mining history everywhere, in fact, Rhandir-mwyn (land of minerals) which is just down the road, was once a prominent industrial hub for mining lead ore and the Nantmwyn mine was the largest in South Wales.
Anyway, I digress, the dam is definitely worth a visit, there are lots of walks around the area and on a quiet day you will no doubt be surprised by the tranquillity and solitude of the place.