The Rotorua geothermal field, New Zealand; Its physical setting, hydrology, and response to exploitation
- DSIR Geology and Geophysics, P.O. Box 30368, Lower Hutt (NZ)
This paper discusses the Rotorua geothermal field which contains New Zealand's only area of geyser activity that has not been significantly affected by power developments. Geophysical and geochemical investigations of the field indicate that it has an area of 18-28 km{sup 2} at about 500 m depth, and a natural heat flux of 430 {plus minus} 30 MW. About a third of its area and over half its heat and mass flux occur beneath the southern end of Lake Rotorua. Aquifer pressure beneath much of Rotorua City is controlled by the lake level, and is uniform due to high permeability in the rhyolitic host rocks. Pressure in the high temperature zone in the south east of the field is about 1.5 bar higher than the rhyolite, and is controlled by the elevation of the main discharges in the geyser area. Although significant natural changes in the geyser activity at Rotorua have occurred historically, the progressive decline of spring and geyser outflows observed since about 1970 was caused by increasing withdrawal from wells tapping geothermal fluids at up to 300 m depth beneath Rotorua City.
- OSTI ID:
- 7255896
- Journal Information:
- Geothermics (International Journal of Geothermal Research and its Applications); (United States), Vol. 21:1/2; ISSN 0375-6505
- Country of Publication:
- United States
- Language:
- English
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