All walks › Tywi Valley and Carmarthen
Tywi Valley and CarmarthenLlyn Brianne
Remote reservoir in the Cambrian mountains with the tallest dam in Britain, reached by a long single-track road and surrounded by forestry and empty hills.
- Distance
- 5.0 mi / 8 km
- Time
- 2 hr 50
- Ascent
- 280 m
- Difficulty
- Demanding
- Shape
- There and back
Where it is
The circle shows the general area, not the exact start. Use the directions link below to get to the car park itself. Contours and paths shown are OpenTopoMap, drawn from OpenStreetMap data.
The route
Tracks run along the shore from the dam into the forestry. Walk out as far as time allows and return; there is no practical full circuit.
Worth knowing
- The dam is a rockfill embankment, the tallest in Britain, and the spillway is dramatic when the reservoir is full.
- The road in from Rhandirmwyn is long, narrow and slow. Allow far more time than the distance suggests.
- No facilities anywhere near. Bring everything.
What you’ll see
The dam and spillway, forested shores, and the empty Cambrians in every direction.
Background
Completed in 1972 to regulate the Tywi for water supply, flooding the upper valley and several farms.