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Tairāwhiti aquifer mapping project features on Ngati Porou Radio  [25/02/2024]

Skip to 3 min 15 sec for a summary of the aquifer mapping project. 

Tairāwhiti aquifer data collection complete, analysis begins

Helicopter flights using aerial electromagnetic (AEM) technology to survey underground aquifers in Tairāwhiti have now finished.


Aqua Intel Aotearoa Programme Director Jane Frances says GNS scientists will now begin the lengthy process of analysing the data, while discussions continue with hapū and iwi on arrangements for accessing, storing and using the data.

“There’s been a fair bit of interest in the helicopter surveying over areas in the north of Tairāwhiti and Poverty Bay flats. I want to reassure everyone that the only aim of this project is to provide Tairāwhiti people with high-quality science and data to support regional decision-making.

Aerial mapping of Tairāwhiti aquifers to get underway this summer

A scientific project gets underway from the end of January 2024 to understand more about Tairāwhiti’s groundwater, after being postponed earlier this year because of Cyclone Gabrielle.

The project involves surveying underground aquifers - areas of natural underground water storage where water flows into and is stored below the ground between rocks and sediment. The surveying will be undertaken by helicopter, using aerial electromagnetic (AEM) technology to ‘see’ under the ground.

Aerial Groundwater Mapping

The Aerial Groundwater Mapping project was initially planned to be undertaken using a helicopter during February, 2023. The widespread effects of cyclone Gabrielle resulted in the project being delayed. The aerial surveying is now planned to start in January 2024. Mapping will be undertaken in Wharekahika (Hicks Bay), Te Araroa, Waiapu, Tologa Bay, and Poverty Bay Flats.

For urgent enquiries please contact:

- Gisborne District Council: 0800 653 800

- Aqua Intel: 

About the Aerial Groundwater Mapping Project

The Aerial Groundwater Mapping project is a scientific investigation to find out more information on the aquifer systems in Tairāwhiti/Gisborne. Aerial mapping of aquifers by helicopter will be carried out in Wharekahika (Hicks Bay), Te Araroa, Waiapu, Tolaga, and across Poverty Bay flats (in the areas shaded orange on the map below).  

We already know some information about the aquifers (e.g., from groundwater drilling) but we want to fill in information gaps. Knowing more about the aquifers will help us to identify the best ways to balance environmental protection, the increased demand for water, and events such as droughts.

Who is supporting the mahi

The project has formed from collaboration between AIA and Gisborne District Council, in discussion with iwi. The $1.8 million project is largely funded through Aqua Intel Aotearoa, a national programme on regional water availability and storage. AIA is a collaboration between Kānoa (the delivery arm of the Provincial Growth Fund) and GNS Science. 

What we want to learn

We will never know everything about the aquifer, but this study will give us a better understanding of:

  • what the aquifer looks like (e.g. depth, extent, geology)

  • how the aquifer is connected to wetlands, lakes and streams

  • the relationship between shallow (unconfined) and deeper (confined) aquifer systems

  • the boundary between the aquifer and seawater (seawater intrusion risk)

  • how groundwater recharges.

How to find out more


What type of surveying will be done?
We will be using the latest airborne electromagnetic technology (AEM) to understand more about some of our aquifers (underground natural water storage) in Tairāwhiti. 

What is involved in AEM surveying
AEM surveying involves flying over the land with a loop system suspended from beneath a helicopter. Transmitters on the loop send electromagnetic signals underground, and sensors measure the behaviour of the returning signals. Similar to radar, this method allows us to ‘see’ what’s under the ground by looking at and interpreting, the way the signals return. 

When will the helicopter be flying the AEM surveying?
The survey was anticipated to begin in early February, 2023 and continuing through March, for about 6 weeks. Preferred conditions for the surveying include low wind, little cloud, and no heavy rain. 

The survey has been delayed (likely until summer 2023/2024), due to the widespread impacts of cyclone Gabrielle. 
UPDATE: The survey is planned for 2024. 

Is AEM safe?
AEM is a safe and effective measurement tool that is used around the world. You may see the helicopter flying overhead but you will not notice any impact from the electromagnetic signals. Airborne SkyTEM is flown at high speed so there is limited exposure to the magnetic field generated from the equipment. The exposure is safer than watching a LCD or plasma TV or blow-drying your hair. 

What about my animals?
The technology is safe to use above animals. Experience in other farming areas is that stock generally aren’t disturbed much by the technology. In New Zealand the team has observed that horses moved to the other side of the paddock when the system came very near. The timing of the survey is summer for the best flying conditions.

What will I see?
You may see a low-flying helicopter towing a large loop hanging from a cable. It will fly over the areas on the below map. The technology will ‘scan’ to about 300 metres deep underground, where we’ve never seen before. We won’t be flying over towns or built-up areas.

How will the helicopter fly the survey?
The helicopter will fly at 80-120 km/hr in parallel lines, generally 175 - 200 m apart, and at a height of approximately 100 m. The measurement instruments are suspended under the helicopter and will be about 30 – 50 m above the ground. The noise from the helicopter has been described as equivalent to a truck going past on a motorway and lasts for around two to four minutes. The helicopter flies up and down in lines, so once it flies over, it will then return approximately 15 minutes later but be at least 200 m further away.

Will the helicopter take aerial images too?
We will not be gathering data or information on anything above ground. While the helicopter will carry a camera, this is only to guide the crew managing the loop, and no photos or video are retained or shared.

What will the information be used for?
The information gathered by the helicopter and loop will take some time to process and analyse. Once available, it will provide a much better picture of the underground water resource and reduce uncertainty to help guide decisions for environmental protection, development, resource consents, water management, and water availability for the local community. The findings will be available to councils, tangata whenua, and community groups, subject to agreed guidelines.

We want to assure you that these flights are not in any way used for compliance monitoring. We only want to know about water.

Who’s involved?
The project is being undertaken by Aqua Intel Aotearoa (a partnership between GNS Science and Kanoa, funded by the Provincial Growth Fund) and Gisborne District Council. The project has been planned in discussion with Te Runanganui o Ngāti Porou, Tāmanuhiri Tūtū Poroporo Trust, Te Aitanga a Māhaki Trust, and Rongowhakaata Iwi Trust. All four iwi have indicated they support the objective of gathering scientific information to guide decision making. Iwi are involved in finalising data management and governance arrangements for accessing, storing and using the data for future purposes.

The SkyTEM data collection is being carried out by the international company SkyTEM in collaboration with the New Zealand helicopter company Heli A1.

What if I have more questions or concerns?
Please contact us if you have any questions or concerns about helicopter flights over your place. Let us know if you have an event you’d like us to avoid (e.g., wedding, hui. livestock) and we’ll do our best to plan around it.

Gisborne District Council: 0800 653 800

Aqua Intel Aotearoa:

Gisborne District Council:



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