The scenic Tawhai Falls are located 2.5km from the junction of SH47 and SH48 on the road to Whakapapa ski field (SH48). Look for the signpost on the left as you head up to the Chateau. Change and walk in along the tourist track for approx 10 minutes.
The line is pretty obvious. The falls used to be run commercially in inflatables (may still be?).
The rest of the river looks quite nice and rocky but class is unknown apart from 2 serious features where the Whakapapanui joins SH47.