TE HIKU WATER STUDY
Helicopter flying over the Northland coast during the Te Hiku aerial aquifer survey.
Credit: Christian H. Sodemann, Senior Field Manager, SkyTEM
Te Hiku Water Study animation
The Te Hiku Water Study in Northland is a scientific investigation to find out more information on the Aupōuri aquifer. This project is backed by the Te Hiku iwi, community and councils, because 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.
About the Te Hiku Water Study
The Te Hiku Water Study is a scientific investigation to find out more information on the Aupouri aquifer.
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.
The project has come from the Te Hiku community, and their strong desire to understand their water resources better. Following a PGF feasibility study and in response to increased water demand and recent droughts, the local community want improved data on the aquifer. This idea became part of an Aqua Intel Aotearoa project on water studies in Northland.
As of September 2023, work is underway to process the raw data so it can be used for hydro-geological interpretation. The next phase of work will see the scientists interpret the processed data by using existing and new bore logs and known geological features for the area. Outputs from interpretation will be 3D hydrogeological maps and a much-improved geological model for the peninsula. These outputs will be used by Council in more accurate and reliable groundwater models to investigate different water use and environmental scenarios before changes to water allocations policies are considered.
Who is supporting the mahi
The $3.3 million research 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 Northland Regional Council, Far North District Council, Ngai Takoto, and Te Aupouri. Aqua Intel Aotearoa is doing the mahi, and a local project team oversees the study.
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 boundary between groundwater and seawater (risk areas for salt-water intrusion)
how groundwater recharges.
Ground-based surveying was carried out in July - August 2021 and aerial surveying was completed in spring/summer 2022. The data was received from SkyTEM in early 2023. and processing has resumed. The project team aim to have outcomes of available by early-mid 2024.
How to find out more
The project team held a series of meetings and hui in Northland during 2021. A copy of the presentation from the 21 July 2021 (Kaitaia) and 22 July 2021 (Pukenui) meetings is available here. Two factsheets are also abailable (see below).
For further information:
FREQUENTLY ASKED QUESTIONS
Why do you need to map the aquifer?
It is important to get more information about the aquifer because of what Te Hiku has experienced over the past few years. The need to protect environmental flows, an increased demand for water, and recent droughts mean we need to get more information. We can then make more informed decisions about balancing water use with environmental protection.
What is the Aupōuri aquifer?
The Aupōuri aquifer is an area of natural underground water storage where water flows into the aquifer between rocks, sediment and shell beds. Water can be drawn from the aquifer, and it also flows out into surface water (e.g., streams, lakes).
This project aims to find out more details about what the aquifer looks like (e.g. depth, extent, geology); how and where the aquifer is connected to wetlands, lakes and streams; identify the boundary between groundwater and seawater (e.g., risk areas for salt-water intrusion) and find out more about how groundwater recharges.
Where is the Aupōuri aquifer located?
The Aupōuri aquifer lies approximately between Parengarenga Harbour, Rangaunu Harbour, and Ahipara Bay. The full extent of the aquifer is one of the questions for the survey to answer.
Why do we need to know more about the aquifer?
Knowing more about the Aupōuri aquifer will help identify the best ways to manage the aquifer, including balancing environmental protection, the increased demand for water, and events such as droughts.
Aerial Electromagnetic Surveying
What type of surveying will be done?
We aim to use aerial electromagnetic (AEM) surveying to map the Aupouri aquifer, because it is the most up-to-date, effective tool available.
In late July and early August 2021, scientists surveyed key locations on private land (with the permission of landowners) using ground-based electromagnetic surveying. This testing was required to provide an indication of whether aerial surveying will provide the data we need.
Note: The aerial surveying was undertaken in autumn 2022.
What is involved in AEM surveying ?Aerial electromagnetic (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 by flying the AEM surveying?
Note: the surveying was completed in 2022.
The exact timing of the aerial surveying is yet to be confirmed. It is expected to be in autumn 2022 (April - May) while the weather is still highly favourable. Low wind, little cloud, and no heavy rain are the preferred conditions for aerial surveying.
How safe is the AEM method?
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.
Te Hiku Water Study
Where did the project originate?
The project idea came from the Te Hiku community and is now part of water studies in the Northland Region being conducted by Aqua Intel Aotearoa (AIA), a collaboration between Kānoa (the delivery arm of the Provincial Growth Fund) and GNS Science.
Who is responsible for the project?
The project is being overseen by the Te Hiku Water Study Project Team, which includes representatives of iwi, landowners and local and regional councils. The Department of Conservation is collaborating with the study.
Who is on the project team?
The project team oversees the study, while the technical work will be undertaken by GNS Science staff and contractors. The representatives from each project partner are:
Ngai Takoto: Wallace Rivers, Craig Wells
Ngati Kuri: Walter Wells
Te Aupōuri: Penetaui Kleskovic
Te Rarawa: Cale Silich
Landowners: Wendy Thomas, Ian Broadhurst
Ratepayers Association: Eric Wagener
AIA: Jane Frances, Ben Pasco
GNS Science: Chris Worts
Northland Regional Council: Susie Osbaldiston, Jason Donaghy
Far North District Council: Shane Storey, Kennith Lewis
Who is funding the project?
The $3.3 million project is mainly funded through AIA. Co-funding is provided from Northland Regional Council, Far North District Council, Ngai Takoto, and Te Aupōuri
AIA is contracting an Australian-based AEM surveying company called SkyTEM to undertake the survey. SkyTEM Australia have undertaken similar work in Hawke’s Bay and Waikato regions.
What will the information be used for?
We need this information to get an initial idea of where the most productive water sources are. This will guide decisions on environmental protection, economic growth and development, resource consents, water management, and water availability for the local community.
Who can access the research information?
The results will be available to councils, tangata whenua, affected landowners, and other stakeholder groups.
What other work is AIA undertaking in Northland?
In addition to the aerial surveying, work is underway monitoring surface water flow in rivers and streams across Northland. Specialists are looking at the potential to harvest and store high surface water flows for use in times of water shortage. In addition, planning is underway to find out more about the Pouto peninsula groundwater, through groundwater drilling.
What if I have more questions about the Te Hiku Water Study?