In September 1964 Cabinet authorised an immediate start on the Tongariro hydro-electric scheme at an estimated cost of £46 million. The first stage of development involves the diversion of water from some of the tributaries of the Wanganui River into Lake Taupo in order to increase the potential energy of the existing power stations on the Waikato River. In the second stage a power station will utilise the 680 ft head of water available between Lake Rotoaira and Lake Taupo. In the third stage the headwaters of the Moawhango River will be diverted into the Tongariro River and thence into Lake Rotoaira. Power stations, to be known as the Rangipo and Kaimanawa, will be built on the Tongariro River above a point where it can be diverted into Lake Rotoaira. The completed scheme will provide about 2,300 million units of electricity.