NAME OF RIVER: Lower Prysor

WHERE IS IT?: The minor road between Gelliydan and Maentwrog


Access – Car park at 52.934043, -3.987094, use the public foot paths to find Rhaeadr Du.

Egress – Lay by at 52.937564, -4.003797 next to the hydro power station.


TIME NEEDED: 30 minutes going blind to three hours scouting it all to a whole night if you get caught out when it’s rising.


WATER LEVEL INDICATORS: Substantial amounts of rain, it rises and drops extremely quickly. There is a marker rock at the get on in the middle of the river, it has shrubs growing out of it. If that is covered then it’s a good starter level. Half a foot more then it’s a brilliant level. Anything over that and then it becomes a much more serious run.

GRADING: Grade 4+ drops in a deep difficult to escape gorge.

MAJOR HAZARDS/ FALLS: Trees, several strainers, large drops, pot holes. Levels rise extremely quickly under certain conditions.

GENERAL DESCRIPTION: This is simply an outstanding river and gorge. All the waterfalls and rapids are clean, smooth and straight forward. Follow the foot path down to the river and plunge pool of Rhaeadr Du. This water-slide type waterfall has seen more than a fair share of descents now. Hop in and paddle the tame section for a few hundred meters, watch out for trees, this is where the river wide strainers are.

Directly after these strainers is the first major drop at around 30 foot not including the short entry rapid. This can be scouted on river left (and trickily portaged). This drops into a cauldron type walled in gorge, in high water it turns into a whirl pool. Follow a slide out of the cauldron. From there to the end of the river is a wonderful supply of drops to the end of the gorge. All of them scout-able from the bank, some of them are must runs but are fairly straight forward. Get out on the left before the arched foot bridge.

OTHER NOTES: This is a fantastic gorge walking river in the summer low levels.  There is a section directly below the Trawsfynydd dam, the reservoir needs to be over flowing for this to run, it’s a serious section that is full of trees. There is one nice rapid half way between Rhaeadr Du and the dam that is worth doing.

Rhaeadr Ddu. Photo - Chris Jackson

On the lip of the 30ft cauldron waterfall. You can just see the slide leading out of the cauldron.