The Tongariro Power Scheme is a 360 MW hydroelectricity scheme in the central North Island of New Zealand. The scheme diverts water from tributaries of the Rangitikei, Whangaehu, Whanganui, and Tongariro rivers. These rivers drain a 2,600-square-kilometre (1,000 sq mi) area including Ruapehu, Ngauruhoe, Tongariro and the western Kaimanawa Ranges. The water diverted from these rivers is sent through canals and tunnels to generate electricity at three hydro power stations, Rangipo (120 MW), Tokaanu (240 MW) and Mangaio (2 MW). The water is then discharged into Lake Taupō where it adds to the water storage in the lake and enables additional electricity generation in the succession of power stations down the Waikato River.

The Whangaehu River is a large river in central North Island of New Zealand. Its headwaters are the crater lake of Mount Ruapehu on the central plateau, and it flows into the Tasman Sea eight kilometres southeast of Whanganui. Due to the high acidity of the water coming from the crater lake, water is not diverted from the headwaters for the Tongariro Power Scheme. Instead, it bypasses the Waihianoa Aqueduct via a ford.