Wairakei is the name of a geothermal area a few kilometres north of Taupo, in the centre of the North Island of New Zealand, on the Waikato River.
With several natural geysers, hot pools and boiling mud pools, it is also the home of a major geothermal electric power generating station. The station was the second large-scale geothermal facility worldwide, and was built in 1958. A second plan was built at another site in the field in 1996, and a binary plant was constructed in 2005 to use lower-temperature steam that had already gone through the main plant.
The use of steam from the field has had a number of visible effects on the local environment. Visible geothermal activity has increased (due to changes in the water table / water pressure allowing more steam to be created underground, upsurging at places like Craters of the Moon), while there has also been some land subsidence and reduction in steam volumes from the field after some decades of use. Some power stations in the field are now capped in their extraction capacities and a substantial part of the water / steam is being reinjected after use.
Source: Wikipedia - from the New Zealand Geothermal Association website