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Southland SkyTEM animation

The Aerial Groundwater Mapping project was undertaken using a helicopter during November and December, 2022. Mapping occurred in the northern Southland region, covering parts of the upper Oreti and Mataura River catchments. The next phase of the project is data interpretation. 

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 northern Southland. Aquifer mapping will be carried out in the northern Southland area covering parts of the upper Oreti and Mataura River catchments.  

We already know some information about the aquifer (e.g., from groundwater drilling) but we want to fill in information gaps. Knowing more about the aquifer 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 Environment Southland, 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. Co-funding organisations include Environment Southland and Great South. 

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

  • how groundwater recharges.

How to find out more


What type of surveying will be done?
From the beginning of November, (we used) the latest airborne electromagnetic technology (AEM) to understand more about one of our critical groundwater resources.

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 occurred in November - December, 2022. Preferred conditions for the surveying include low wind, little cloud, and no heavy rain. 

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 early summer for the best flying conditions but is also seeking to avoid the main lambing and calving seasons in Southland.

What will I see?
During an AEM survey, you may see a low-flying helicopter towing a large loop hanging from a cable. It will fly over the area on the below map and ‘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 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. It 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.

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 (eg a stock sale, wedding, hui) and we’ll do our best to plan around it.



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