Stroll - Circuit of the Tanygrisiau reservoir

A moderate circular stroll around the Tanygrisiau Reservoir.

Plenty opportunities for dogs to paddle. Great little (dog-friendly) cafe beside the station at Tanygrisiau.

The reservoir is part of the Ffestiniog Power Station complex. This installation was the first major pumped storage system in the UK. Pumped storage is a way of coping with rapid, short-term changes in the demand for electricity in the National Grid. At times of low demand and excess production elsewhere on the grid, water from the lower Tanygrisiau reservoir is pumped back up to the upper Llyn Stwlan reservoir. At times of sudden demand, water is released from Llyn Stwlan, to generate power as required. For this reason, the levels of both the Tanygrisiau and Llyn Stwlan resevoirs can change significantly day-to-day.

The building of the lower reservoir flooded the route of the Ffestiniog Railway which had to build a deviation around the reservoir and power station.


From A496 to Blaenau Ffestiniog, follow brown signs to “Power Station”. You will reach Tanygrisiau Station at the top of the ascent, opposite the dam, and before you reach Lakeside Cafe. 



2 stream crossings on stepping stones (but can be detoured). A small number of stiles and 3 kissing gates. Short section alongside a quiet public highway.

Reservoir water levels can vary, which may affect exact route taken.

Slightly boggy underfoot in places, but easily detoured.