Te Whakaheke o Te Wai – understanding New Zealand’s groundwater

Te Whakaheke o Te Wai is a world-leading research programme that is building a better understanding Aotearoa New Zealand's largest freshwater resource.

The name loosely translates to "meandering waters" and reflects the complex and ambiguous nature of groundwater systems. As aquifers and river catchments are hidden underground, we have a limited understanding of how the water flows, and how long that takes.

“Not having the full picture of New Zealand’s groundwater is the main reason that groundwater resources are not being managed sustainably,” explains Dr Catherine Moore, Team Leader of Groundwater Modelling at GNS Science.

“Te Whakaheke o Te Wai will give us the knowledge we need to build a more comprehensive picture of groundwater – one that will support better management of this precious taonga”.

The GNS-led research team is collecting complementary hydrogeological, chemical and isotope data to trace the origins, age and flow pathways of groundwater across the country. Combined with mōhiotanga Māori (Māori understanding), this data is already providing insights into the effects of geology and different seasons on groundwater systems.

A key part of this programme is evolving groundwater modelling capabilities that will better integrate isotope tracers, mātauranga (knowledge), and other data across a range of scales. These new meta-models allow for multiple sources of information and data to be run in parallel, reducing the inherent uncertainty of basic models.

Using this meta-model approach, the team are mapping Aotearoa New Zealand’s 200 known aquifers and abundant river catchments. This will be the world’s first nationally continuous maps of groundwater age, origin and flow paths.

They have already completed detailed mapping of groundwater on the Heretaunga Plains, including an aquifer critical to the Hawke’s Bay community.

“[The programme] is getting into some novel research and practical science that is pushing the limits of what’s been done before, it’s really quite exciting” says Jeff Smith, Science Manager at Hawke’s Bay Regional Council”.

Deeper knowledge of Aotearoa’s groundwater will boost freshwater quality and security of supply – which will benefit drinking water safety, cultural values and sustainability for agriculture, tourism, and regional economies.

The team are working hard to keep communities informed about the health and protection of their water. The research outputs of the programme will be made publicly available, and the team are developing a website and series of outreach videos.

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