Aberdulais Falls

Power has been drawn from the waterfall since 1584, when it first provided energy used in the manufacture of copper, using ore imported from Cornwall. The copper-works ceased to operate early in the 17th century, and the site was later used for corn-milling and later as a tinplate works. The weir and waterwheel were added during the 19th century. The waterwheel used today is a modern steel structure. It is the largest waterwheel generating electricity in Europe, with a diameter of 8.2 m. It has 72 buckets to catch the falling water and rotates at a rate of five revolutions per minute.

The River Dulais rises on Mynydd y Drum in the western Brecon Beacons. It flows down the Dulais Valley, through the villages of Seven Sisters and Crynant, before reaching its confluence with the River Neath after about 7 mi. Here it flows over a ridge of Pennant sandstone, entering a gorge that was carved by meltwater from a glacier 20,000 years ago. Originally the falls were nearer the sea, but the water has eroded the rock and cut its way back to its present location. The River Dulais is prone to flash floods when heavy rain falls in its catchment area.