An alternative start for the Mellte that requires a short walkin to reach. A difficult run with a number of waterfalls. Watch out for a number of gorge sections that often end in something nasty/impossible. In general river right is best for scouting/portaging. You join the Mellte about halfway down, and continue down to the normal Mellte takeout at Dinas Rock carpark.
Park at a layby on the A4059 north of Penderyn (just north of a cattle grid next to a rpivate road that heads towards a farmhouse near the river). From here walkin to the river along a footpath, don't use the private road. There is an alternative footpath in from Penderyn itself, but you miss out on the top bit of the run. The takeout is at a large carpark by a small stone bridge that you'll reach if you keep driving through the Pontneddfechan towards the river (east).
Rainchasers is best experienced as an app.