The Mangaturuturu Rapids is a long series of cascades, where the Mangaturuturu River descends into the Mangaturuturu Valley over an old lava flow.
The Upper Cascades are shorter but steeper. As the river cascades over the volcanic rocks, it coats them with a white substance. This white lining is allophane, which is precipitated from water fed by springs enriched with CO2 that enters the groundwater system from a geothermal source. (This is one of only two locations in New Zealand where this occurs.)
The Lower Cascades are a bit more gentle, and arguably more photogenic than the Upper Cascades.
On a clear day, you can see Mount Ruapehu behind the cascades.
Getting to Mangaturuturu Rapids
The Mangaturuturu River cascades are about 2km from Ohakune Mountain Road, along the Round the Mountain Track. The walking trail closely follows the upper cascades, before crossing the river and descending a very steep rock outcrop. It then descends less steeply along the lower cascades.