6 - Eyri ( Snowdon National Park ) - Misc
Tanygrisiau Reservoir / Llyn Ystradau
A view from the spoil tip, above the upper Tanygrisiau car park, over the Tanygrisiau Reservoir / Llyn Ystradau.
The Ffestiniog Hydro Electic Power Station is on the right with a 550m long concrete gravity dam to the left.
Water from Llyn Stwlan drives 4 turbines to generate electricity , in off peak periods the turbines act as pumps to force water back up to Llyn Stwlan.
The water level rises and falls by 20m. in Llyn Stwlan and 5.5 m. in Tanygrisiau Reservoir during the daily operation of the station.
Ref: NW 4678
Date: 28/07/2025
Location: SH 6834 4549
