The Rotomā-Tikorangi geothermal system is nested within the north-eastern corner the Haroharo-Ōkataina volcanic caldera. The system has a small surface expression manifested by few thermal surface features including steaming ground, small fumaroles and warm springs.
Although the surface features are not well developed they are wide spread. There is steaming ground and small fumaroles at Tikorangi (80–97°C) and two areas of warm springs 3-4km further to the north (Waitangi) and northeast.
(Otei) springs flow into lakes Rotoehu and Rotomā respectively. Warm springs at Mangakotukutuku located about 7km south of Tikorangi are also considered part of this system.
The Waitangi Spring discharges diluted mixed chloride-bicarbonate waters at 49°C.
Use and development
Local Māori mined sulphur in this area up until the 1950’s. Five shallow exploration holes were drilled in 1969 for sulphur prospecting; one hole erupted during exploration and measured steam pressure indicated temperatures of 134°C are present.
A few domestic shallow wells are present. The deeper subsurface has been explored by a single exploratory well (RM1) drilled in 1985. It was drilled near Tikorangi to a depth of 1500m.
At Waitangi on the shore of Lake Rotoehu a pool and bath complex has been created to use the warm waters. No routine monitoring of the surface features, outflows or heat are made except for chemical sampling of a spring by the GeoNet project at Waitangi.