The largest river rising on Ruapehu, the Whangaehu river is counted among the top ten North Island rivers for rafting and kayaking. The most popular run is the section from Tokiahuru Stream to Collier’s Bridge. With above average flows the rapids are Grade 3–4 with tight, big boulder chutes and drops.
Tracing its way from the Crater Lake of Mt Ruapehu the sacred Whangaehu River flows 135km southward to the driftwood strewn shores of the South Taranaki Bight. The river is sacred to Maori in the region.
The Whangaehu River provides excellent fishing and some of its tributaries contain a dense population of small rainbow trout in their upper reaches.