Te Whakaheke o Te Wai

This project aims to better support water management based on improved understanding and integration of flow sources, pathways, water travel time, and cultural knowledge and values.

Overview

The research is underpinned by the concept of Te Whakaheke o Te Wai (the pathways of the water), tracing groundwater throughout the main catchments and aquifers of Aotearoa New Zealand.

Te Whakaheke o Te Wai holistically describes the flow sources, pathways and lags of water moving through a catchment. For groundwater – our largest freshwater resource – this remains largely unknown. This paradigm-shifting project will derive the whakaheke of groundwater and baseflows in New Zealand’s 200 major aquifer systems and the rivers that drain them.

Outputs from this research will provide decision-makers with much-needed knowledge for improved water management at national, catchment, and local scales. The programme is currently developing the world’s first nationally continuous maps of groundwater age, origin and flow paths. Outputs will be publicly available and benefit people and institutions involved in water management.

This programme aims to

  • develop a world-first series of maps showing the source and flow patterns of New Zealand’s 200 known aquifers and large river catchments
  • increase our scientific understanding of flow sources, pathways, and lags of groundwater
  • give us valuable information about the age, source and destination of groundwater in our aquifers
Te Whakaheke o Te Wai (2021) – This project focuses on the groundwater systems in Hawke’s Bay’s Heretaunga catchment, and the nature of the water and how it flows through these lands. transcript

The name of this research program is Te Whakaheke o Te Wai or loosely translated the meandering waters, and that is a reflection of our groundwater systems and also our focus that we're working in Hawke's Bay on, on the Hirotanga catchment, and the nature of the water and how it flows through our lands.

The aim of the project is to better understand groundwater flow, the pathways of groundwater flow and the origins of groundwater beneath the surface with the idea that if we can understand it better we can manage it better.

The project is a sort of sum of three parts isotope science mataranga knowledge and modelling and I lead the modelling stream. And what we're doing is to build a framework that allows models to be built very very quickly as soon as there's a concern and you tailor the model to answer the question or the concern that it's meant to be addressing, and they'll answer the question a lot more accurately.

So my role in this project is to ensure that mataranga maori or maori knowledge is incorporated into this project.

It's important that we increasingly and incorporate indigenous knowledge with western science when we're trying to and better understand things particularly in this case around the water and how we can better look after this resource that we have.

For Hawke's Bay and one outcome from this project is that we are definitely going to be able to manage our water resources much more effectively, but as a nation I think having these tools that can be applied nationally will help address the some of the big problems we have with water resource management that are fairly consistent across the country.

Over many years I have been developing techniques to read the isotopic signature of groundwater which can tell us about what where the water is being recharged so the recharge source, but also how long it has been underground which then will give us a better understanding of how to manage groundwater resources.

Apart from just the tools that this project's going to provide, I think it's one of the best things about it is working with a really really super talented bunch of people at GNS science, and getting into some novel research and practical science that is pushing the limits of what's being done before so in that respect it's really quite exciting.

Te Whakaheke o Te Wai (2021)

This project focuses on the groundwater systems in Hawke’s Bay’s Heretaunga catchment, and the nature of the water and how it flows through these lands.

To achieve these objectives we are

  • conducting a national groundwater and surface water age tracer sampling campaign, and stable isotope sampling programme
  • using both western science and mātauranga Māori as part of our research
  • using new modelling approaches to better integrate tracers, mōhiotanga Māori, and other data from national scale through to local drinking water

The Project

Our research

We will measure age tracers, which integrate all flow velocities (of water and contaminants) above any measurement point. We will use complementary hydrogeological, chemical and isotope data to understand origin of recharge and flow pathways, effects of geology, seasonality and stream order. New modelling approaches will integrate the tracer and other data across scales.

The metamodel-data assimilation will yield New Zealand’s first national maps of groundwater age, origin and flow paths, useable for all institutions involved in water management.

Working with hapū, iwi, and national Māori partners, we will incorporate mātauranga-a-iwi/hapū into our models alongside the tracer and other related data. We will research use of these models across institutional boundaries to promote a collective understanding of the whakaheke of water, its relationship to whakapapa and its role in empowering kaitiakitanga.

Applications of the research outputs will include informing: setting of national policies, managing catchment scale contaminant inflows to groundwater-fed rivers, and protecting local potable water supplies (e.g. Havelock North).

Our research involves four complementary areas

Environmental tracer survey: world-leading methods, unprecedented coverage

For over 300 years, rainfall-runoff and groundwater models have been calibrated to measurements of hydraulic head and stream flow. These data provide little insight into groundwater age or transit time as needed for improved water management. Environmental tracers, notably isotopes, give the most direct data informing flow models.

We will measure age tracers, which integrate all flow velocities (of water and contaminants) above any measurement point. We will use complementary hydrogeological, chemical and isotope data to understand origin of recharge and flow pathways, effects of geology, seasonality and stream order.

Merging mātauranga-a-iwi/hapū with western science improves conceptual understanding

Historically, conceptual understanding of groundwater systems has been based on western science. It is increasingly recognised that indigenous knowledge also provides expert insight into freshwater systems.

In New Zealand, mātauranga-a-iwi/hapū, as it pertains to landscape, springs and rivers, derives from cultural perspectives and close association with the environment. This knowledge is preserved by long oral traditions and thus can provide insights that extend into the past beyond the modern instrumental record. Increasingly, this mātauranga is applied in cultural health monitoring of rivers and supporting improved water policy and planning. The challenge is that mātauranga-a-iwi/hapū pertaining specifically to groundwater presently has low visibility, so its influence remains limited.

Working with hapū, iwi, and national Māori partners, we will incorporate mātauranga-a-iwi/hapū into our models alongside the tracer and other related data.

Advanced workflows for rapid, accurate modelling at relevant scales

Only by bringing data and expert knowledge together in a numerical model is it possible to make predictions for locations without data, or to explore ‘what if’ scenarios (e.g. increased abstraction, land use change). Industry-standard groundwater software is now routinely used for these purposes, in NEW ZEALAND  and globally.

The challenge is that current methods for model calibration and uncertainty analysis are not suitable for depicting TWOTW because:

  • they do not readily integrate tracer and other data alongside expert knowledge and mātauranga-a-iwi/hapū
  • they do not effectively represent highly connected flow pathways
  • national, regional and local scales cannot be examined within a single model due to prohibitively slow run times.

 

Better use of data, knowledge and models in the decisions that matter

Historically, many scientific investigations were conducted to advance the state of knowledge in general, without a specific application in mind. It is increasingly recognised that, to improve our water management, these investigations must be tailored from the outset to address specific water management issues we face. The challenge is that different water management organisations have different information needs depending on their various mandates and scales of operation.

  • Project Updates

  • Publications

    Journal publications

    Hemmings, B, Knowling, M.J., and Moore C.R., 2020. Early uncertainty quantification for an improved decision support modelling workflow: A streamflow reliability and water quality example. Frontiers in Earth Science. doi: 10.3389/feart.2020.565613.

    Knowling, M.J.; White, J.T.; Moore, C.R.; Rakowski, P.; Hayley, K. 2020 On the assimilation of environmental tracer observations for model-based decision support. Hydrology and Earth System Sciences, 24(4): 1677-1689; doi: 10.5194/hess-24-1677-2020(external link)

    White, J.T., Hemmings, B., Fienen, M.N., Knowling, M.J., 2021. Towards improved environmental modeling outcomes: Enabling low-cost access to high-dimensional, geostatistical-based decision-support analyses. Environmental Modelling and Software. Volume 139, May 2021, 105022 https://www.sciencedirect.com/science/article/pii/S1364815221000657?dgcid=coauthor(external link) 

    Reports

    Dudley, B., Yang, J., Shankar, U., 2020. Estimated young water fractions at NIWA river water quality network sites. Prepared for GNS Science September 2020. NIWA CLIENT REPORT No: 2020287CH.

    Morgenstern U., Davidson P., Townsend D.B., White P.A., van der Raaij R.W., Stewart M.K., Moreau M., and Daughney C. 2019. From rain through river catchment to aquifer: the flow of water through the Wairau hydrologic system. Lower Hutt (New Zealand ): GNS Science. 83 p. (GNS Science report; 2019/63). doi:10.21420/7125-ST46

    Aranui, A. 2020. Te Whakaheke o te Wai: Mātauranga a Iwi/Hapū Research Report. Victoria University of Wellington.

    Conference Presentations

    Daughney C.J., and Morgenstern U., 2020. Use of symbolic regression to estimate groundwater age distributions from hydrochemistry, Heretaunga Plains. In:  New Zealand  Hydrological Society Conference, from 1 – 4 December 2020, Invercargill Waihōpai, New Zealand : oral abstracts. [Wellington, N.Z.]: New Zealand Hydrological Society.

    Dudley, B.D., Shankar, U., Yang, J., and Montgomery, K. 2019. Development of a surface water isotope layer for New Zealand. In: New Zealand  Hydrological Society Conference 3-6 December 2019, Rotorua, New Zealand  :oral abstracts. [Wellington, N.Z.]: New Zealand Hydrological Society.

    Johnson, P.J.; Morgenstern, U.; Moore, C.R.; Cameron, S.G. 2019 Te Whakaheke o te Wai : improving understanding of groundwater flow pathways in New Zealand. p. 90 In: New Zealand  Hydrological Society Conference 3-6 December 2019, Rotorua, New Zealand : oral abstracts. [Wellington, N.Z.]: New Zealand Hydrological Society.

    Moore, C., 2019 Keynote Speaker, New Zealand HS. Model design for decision support: uncertainty quantification, data assimilation and model complexity entanglement. In: New Zealand  Hydrological Society Conference 3-6 December 2019, Rotorua, New Zealand  : oral abstracts. [Wellington, N.Z.]: New Zealand Hydrological Society.

    Moore, C. and Doherty J. 2020. How upscaling hydraulic properties undermines the reliability of our decision-support predictions. In: New Zealand  Hydrological Society Conference, from 1 – 4 December 2020, Invercargill Waihōpai, New Zealand  : oral abstracts. [Wellington, N.Z.]: New Zealand Hydrological Society.

    Morgenstern, U., Davidson, P., Townsend, D., Stewart, M.K., 2019. Groundwater Storage that feeds the Wairau River and Streams in the Wairau Plain. In: New Zealand  Hydrological Society Conference 3-6 December 2019, Rotorua, New Zealand  : oral abstracts. [Wellington, N.Z.]: New Zealand Hydrological Society.

    Sarris T., Scott, D.M., Close, M.E., and Moore C., 2020. Transition Probability Analysis of Lithology data: Implications for numerical delineation of well capture zones. In: New Zealand  Hydrological Society Conference, from 1 – 4 December 2020, Invercargill Waihōpai, New Zealand  : oral abstracts. [Wellington, N.Z.]: New Zealand Hydrological Society.

    Toews, M.W.; Hemmings, B.J.C. 2019 A surface water network method for generalising streams and rapid groundwater model development. p. 166-167 In: New Zealand  Hydrological Society Conference 3-6 December 2019, Rotorua, New Zealand  : oral abstracts. [Wellington, N.Z.]: New Zealand Hydrological Society.

    Yang, J., Jakeman A., and Rajanayaka, C., 2019. Emulation methods for sensitivity and uncertainty analyses in hydrologic modelling. MODSIM Conference. 2019, Canberra, Australia.

    Outreach and community

    Aranui, A., 2019. 'Mapping Whenua: Te Whakaheke o te Wai: Mātauranga a iwi me ngā hapū' at Victoria University of Wellington for Te Kawa a Māui course MAR203 Mapping Whenua.

    Morgenstern U., 2019. Wairau Aquifer Envirolink project, presented to the Environment Committee at Marlborough Regional Council. 

    Presentation and discussion at Fish hook summit https://www.kahungunu.iwi.nz/fish-hook-programme(external link)

Research programme details

Collaborators: NIWA, ESR, Te Tai Whenua O Heretaunga (Hawke’s Bay, New Zealand), Victoria University of Wellington (VUW, New Zealand), Watermark Numerical Computing (AUS)

Additional collaborators: HBRC, ECan, Monash University, University of Saskatchewan, Luxembourg Institute of Science and Technology, HDC, HBDHB, MfE, Ngāti Kahungunu Iwi Incorporated

Duration

2018–2023

Funding platform

2018 Endeavour Fund – Research Programmes

Status
Programme leaders

Catherine Moore, GNS science
Uwe Morgenstern, GNS Science

Funder

Funder: Ministry of Business, Innovation & Employment (MBIE)

Co-funders: Institute GNS Science; National Institute of Water and Atmospheric Research (NIWA), New Zealand; Institute of Environmental and Scientific Research (ESR), New Zealand; Hawke's Bay Regional Council, New Zealand;
Environment Canterbury Regional Council, New Zealand; Monash University, Australia; University of Saskatchewan, Canada; Luxembourg Institute of Science and Technology; Hastings District Council, New Zealand; Hawke’s Bay District Health Board, New Zealand; Ministry for the Environment, New Zealand; Ngāti Kahungunu Iwi Incorporated, New Zealand

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