Hawke’s Bay 3D Aquifer Mapping (3DAMP)

Hawke’s Bay is the first council in the country to use the latest airborne dual-moment time-domain electromagnetic survey technology (SkyTEM) to scan their aquifers to depths of ~500 m.

Overview

GNS Science and Hawke’s Bay Regional Council partnered on the largest-scale groundwater mapping project ever done in New Zealand. The Hawke’s Bay 3D Aquifer Mapping Project (3DAMP) is a three-year initiative (2019–2022) jointly funded by the Provincial Growth Fund, Hawke’s Bay Regional Council and GNS’ Groundwater Strategic Science Investment Fund (SSIF) research programme.

The 3DAMP project aims to deliver a significant advancement in the detailed understanding of the region’s underground freshwater resources and enable more effective management of these resources. It will also advance our ability to map aquifers from local to national scale and provide decision-making tools that could be used by councils all over New Zealand.

The project applies SkyTEM technology to improve mapping and modelling of groundwater resources specifically within the Heretaunga Plains, Ruataniwha Plains and Poukawa and Otane basins. 3DAMP involves collaboration between HBRC, GNS and the Aarhus University HydroGeophysics Group.

The SkyTEM system was developed by the Aarhus University HydroGeophysics Group in Denmark. It is a geophysical technique that uses electromagnetic waves to investigate the shallow (up to 500 m) resistivity structure of the earth.

Close to 8,000 line km of data were collected in Jan/Feb 2020 by SkyTEM Australia Pty Ltd. using a helicopter equipped with a SkyTEM system.

Using the collected data, the development of resistivity models and hydrogeological models is currently underway.

The programme aims to

  • enable Hawke's Bay Regional Council to better manage its water resources in line with community values and aspirations
  • enable the Hawke’s Bay’s economy to further transition to high-value less animal-intensive, lower nutrient-producing activities
  • Provide decision-making tools that can be rolled out to other councils around New Zealand

To achieve these objectives

  • data was collected across the Ruataniwha Plains, Heretaunga Plains and the Poukawa and Otane Basins
  • pre-existing supporting data will be compiled and assessed, and some additional data collected through a drilling programme
  • the data will be processed and resistivity models developed
  • the resistivity models will be analysed alongside the supporting datasets, and hydrogeological models developed
  • the Hawke's Bay Regional Council’s numerical groundwater models in the Heretaunga Plains will be updated with these data
  • the developed models will be made publicly accessible through online tools

Hawke's Bay 3D Aquifer Mapping project overview and update (HBRC, 2021)

GNS Science hydro-geophysicist Zara Rawlinson talks about the 3D Aquifer project at the 2020 New Zealand Hydrological Society, NZ Rivers Group and New Zealand Freshwater Sciences Society joint conference in Invercargill.

The project

Why use airborne electromagnetic data?

Traditional methods of gathering data from drilling or ground-based surveys are slow, costly, provide poor spatial data coverage, and generally don’t go deep enough.

Aerial mapping, on the other hand, can cover large areas of ground quickly and cost-effectively, giving high levels of detail on the subsurface. Developed by Aarhus University in Denmark, it provides a 3D view of the subsurface to about 500m (depending on the noise and geology). In comparison, most available information from boreholes within the Heretaunga Plains is within the upper 50m.  

Aerial mapping is sensitive to rock type, porosity, permeability, clay content, moisture content, and properties of the water. These all help in understanding and mapping aquifers.

Example map

Adding more to the picture

Data was collected in January and February 2020. A drilling programme is currently underway to collect additional data to support hydrogeological interpretations.

GNS is currently working on the processing and inversion of the electromagnetic dataset and hydrogeological interpretations of these data.

The final stage of the project will involve using the new information for numerical groundwater modelling in the Heretaunga Plains.

GNS is also currently working with HBRC to develop an online interface to provide easy access to the 3D models being developed.

Zara Rawlinson Hydro-geophysicist

Zara is a Hydro-geophysicist at GNS Science’s Wairakei Research Centre with a particular interest in the use of geophysics for subsurface imaging and property determination, as well as developing 3D subsurface geological and numerical models for groundwater applications. Zara’s background includes research focussed on mathematical inversion techniques, seismic signal processing and software/programme development. Recent work has focused on electromagnetic applications within groundwater research, particularly utilising the airborne SkyTEM system, including the planning, communicating, processing, and geophysical and hydrogeological modelling aspects of these projects.

View Bio Contact Me
Research project details

Collaborators: Hawkes Bay Regional Council, Aarhus University HydroGeophysics Group (Denmark)

Duration

2019–2022

Funding platform

MBIE-funded Provincial Growth FundGNS Science’s (GNS)
MBIE-funded Groundwater Strategic Science Investment Fund (SSIF) research

Status

Current

Programme leader

Zara Rawlinson, GNS Science

Funder

New Zealand Ministry of Business, Innovation & Employment (MBIE), Hawke’s Bay Regional Council

Find more content related to:

GNS Science topics