The Rangipo region is largely uninhabited. It is used by the New Zealand Army, based at Waiouru in the south, and by the Rangipo prison farm in the north and Rangipo underground HEP station to the east. During the 1960s The Tongariro power scheme redirected the flow of water from many of the streams and rivers that drain the central peaks. The water was channelled into canals, tunnels and storage lakes to provide water for 2 HEP stations at Rangipo and Tokaanu. The water then flowed into Lake Taupō increasing its input by 20%. Most of the Tongariro river flow is not included in the power scheme due to its importance as a breeding area for brown and rainbow trout. The extra water boosted the amount of water available to the 10 other HEP stations on the Waikato River which flows from the north end of the lake and is its only exit.