3 Sept 2025: geothermal tomo

Media: Rotorua Daily Post

Topic: Geothermal tomo at Whakarewarewa Village

Enquiry

*NOTE: this is further to a previous enquiry relating to the geothermal tomo at Whakarewarewa Village https://www.rotorualakescouncil.nz/our-council/news/news?item=id:2vdhxcd2k17q9s5qt7gd

I’m preparing a story for the Rotorua Daily Post on the geothermal sinkhole that has closed Wāhiao Drive into Whakarewarewa Village, and would appreciate a response to the questions below:

• What time did the geothermal sinkhole occur on August 24?
• When was Wāhiao Drive last maintained and serviced?
• Does Rotorua Lakes Council carry out regular assessments on Wāhiao Dr? If so, what do these assessments involve, and how often do they occur?
• What is the Council's proactive road maintenance programme for Wāhiao Dr?
• What changes did the council make in how it monitors/maintains this road following the Worksafe case of 2022, and have these made a difference in the approach to this new tomo?
• A Rotorua Lakes Council spokesperson said: “We will monitor the area regularly while exploring possible options for a long-term solution.” What possible long-term options are currently being explored?
• Can you clarify whether the long-term solution being explored is intended just to address this particular sinkhole on Wāhiao Drive, or whether it will also include wider measures to prevent future geothermal holes in the area?
• Since August 24, how often has the site been monitored?
• When does the council expect Wāhiao Dr will reopen?
• Has Council received any complaints or reports regarding the closure? If so, what has been the nature of these and how many have been received?

Response

Responses can be attributed to General Manager Infrastructure and Assets, Stavros Michael:

What time did the geothermal sinkhole occur on August 24?

It’s not possible to determine this – a tomo can develop very quickly or over time and rainfall can accelerate or trigger this natural occurrence. They cannot be accurately predicted or prevented and are a common feature/hazard in geothermal areas.

When was Wāhiao Drive last maintained and serviced?

Council’s roading contractors carried out some minor cobblestone maintenance in the area on 14 August.

It’s important to note the formation of a tomo is not road maintenance-related – it is caused by unpredictable geothermal activity, potentially exacerbated or triggered by rainfall prior to the actual ground collapse.

Does Rotorua Lakes Council carry out regular assessments on Wāhiao Dr? If so, what do these assessments involve, and how often do they occur?

Council’s roading contractors carry out routine visual inspections on Wāhiao Dr every 2 months and take action if/as needed.

The council also collaborates with the village operators/community who notify us of anything unexpected they observe on the road. These reports are promptly responded to, assessed and addressed as required.

What is the Council's proactive road maintenance programme for Wāhiao Dr?

See above

What changes did the council make in how it monitors/maintains this road following the Worksafe case of 2022, and have these made a difference in the approach to this new tomo?

Rotorua Lakes Council maintains a proactive road maintenance programme across its roading network, including in Whakarewarewa Village and residents and tourism operators there also notify council about any changes in geothermal activity or features/hazards they observe.

NOTE FOR REPORTER: Please ensure accurate reporting of what you have called “the WorkSafe case of 2022” – ultimately there was no case. When the matter came up in court early this year WorkSafe offered no evidence and it was dismissed.

A Rotorua Lakes Council spokesperson said: “We will monitor the area regularly while exploring possible options for a long-term solution.” What possible long-term options are currently being explored?

We are still assessing the situation to help us determine the options and it would not be helpful to speculate about what those could be.

Can you clarify whether the long-term solution being explored is intended just to address this particular sinkhole on Wāhiao Drive, or whether it will also include wider measures to prevent future geothermal holes in the area?

Due to the unpredictable nature of geothermal activity it is not possible to predict or prevent these types of natural events from happening.

Council has a proactive and reactive road maintenance programme and this will continue, along with reporting by residents and tourism operators in the village.

Rotorua is situated in an active geothermal area and events like this will happen naturally from time to time.

NOTE FOR REPORTER: if you haven’t already done so, we would strongly encourage you to contact Brad Scott at ESNZ/GNS to assist you in understanding the nature of geothermal activity and events such as tomos. He’s happy to speak with you. His email address is b.scott@gns.cri.nz

Since August 24, how often has the site been monitored?

The site is being inspected daily. No change has been observed.

When does the council expect Wāhiao Dr will reopen?

It’s not possible to determine that at this time.

Alternative access into and out of the village has been established in the meantime and the tourism business is operating.

Has Council received any complaints or reports regarding the closure? If so, what has been the nature of these and how many have been received?

Council continues to work closely with Whakarewarewa Village representatives.

We have received no complaints regarding the closure.