Geyser’s revival of international significance

Geyser’s revival of international significance

For immediate release
12 October 2013

Revival of Papakura Geyser in Rotorua’s Whakarewarewa geothermal valley may be a world first, Bay of Plenty Regional Council Chief Executive Mary-Anne Macleod says.

The Regional Council manages the Rotorua Geothermal Field through the Rotorua Geothermal Plan, which constrains use of the resource to protect geothermal features.

“These geothermal features have great local, national and international significance and we acknowledge and recognise the geothermal field as a taonga for tangata whenua,” Ms Macleod says. “The revival of Papakura is great news not only for Rotorua, but for all those who have been involved over the years in monitoring and protecting these precious assets.”

Bay of Plenty Regional Council Senior Planner Bridget Robson says the Rotorua Geothermal Plan has tightly managed the resource and it appears this action has something to do with the geyser’s recovery.

“This could be the first time in the world a management response to a geothermal decline has had this type of result. Usually when geysers have stopped erupting they have tended to stay that way. What’s happening here suggests there is a big lag period between changing use patterns and the geothermal system responding. This will be of interest internationally,” Ms Robson says.

Papakura was one of Whakarewarewa’s most consistently active geysers and has been dormant since March 1979 but is now “bubbling away” with temperatures reaching boiling point and a series of small eruptions spraying steam and water up to a metre high.

“She is showing signs of being a geyser again – this is very exciting.”

The Rotorua Geothermal Plan came into effect in 1999, maintaining a 1.5km exclusion zone around Pohutu Geyser at Whakarewarewa, a zone established in 1986 to halt the progressive decline in surface geothermal activity. It saw the closure of hundreds of bores in the city.

Following the closures there were signs of recovery of geysers, springs and other geothermal features. Groundwater levels bounced back fairly quickly, Kuirau Park came back to life, Pohutu Geyser became more active again – but the recovery of other surface features was slower and Papakura, among other features, remained dormant.

Regional Council became responsible for managing the geothermal field in 1991 and developed the Rotorua Geothermal Plan to protect the field and bring about recovery. It sets out policies and rules for the use of geothermal energy, puts a cap on the amount of geothermal fluid and heat that can be used, promotes low-effect use and includes ongoing monitoring.

Bay of Plenty Regional Council will continue to work with the community, local council, tangata whenua and the business sector to meet needs, advance opportunities and preserve and enhance geothermal resources.

Papakura showed no signs of recovery until recently when routine monthly monitoring by scientists from GNS, which carries out this work for the regional council, showed increased levels of chloride geothermal fluid, indicating increased fluid flows from deep underground.

Ms Robson says the regional council will continue to work with GNS to better understand the Rotorua geothermal system and the impact of use of the resource.

The Rotorua geothermal field’s surface features and unique ecosystems make it of high scientific and conservation value internationally.

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For further media information please contact Ingrid Tiriana, Senior Communications Advisor, on 0800 884 881 Ext 8150 or (021)190 8868.

Background

Bore numbers in Rotorua increased significantly through the 1950s and 1960s and in the 1970s

there was significant decline in surface geothermal activity, especially at Whakarewarewa.

This was believed to be the result of a reduction in the geothermal aquifer water level, due to extensive withdrawal of geothermal fluid from bores and no reinjection.

In 1980 the Minister of Energy and Rotorua District Council set guidelines for drilling and use of geothermal energy in Rotorua. A monitoring programme began in 1982 and a taskforce was formed in 1983 to assess the extent of geothermal fluid draw-off and investigate ways to reduce it.

In 1986, prompted by increasing concern about the effects of geothermal energy use on the geysers at Whakarewarewa, the government ordered the closure of all bores (106) within 1.5km radius of Pohutu Geyser and the closure of all government department bores in Rotorua city. Bore closures began in 1986 but most occurred during 1987.

The government also introduced a royalty scheme for those extracting geothermal fluid across the field and promoted reinjection of geothermal fluid back into the field.

The number of bores dropped from 376 to 141, resulting in a 30% drop in total mass withdrawal. A 50% increase in deep bore reinjection reduced net withdrawal by 86% by about 1991.

Following the bore closures geothermal groundwater levels increased, Kuirau Park came back to life, Pohutu Geyser became more active again – but the recovery of other surface features was slower and Papakura, among others, remained dormant.

Whakarewarewa has the largest collection of surface geothermal features in Rotorua with at least 65 recognisable geyser vents although only about a handful will have been active at any one time.

In Rotorua there are about 1550 geothermal features, ranging from steaming ground to the spectacular geysers.

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