A review of freshwater models used to support the regulation and management of water in New Zealand
Catchments in the top of the South Island, bottom of the North Island. Source data: MfE Data Service (data.mfe.govt.nz) and LINZ Data Service (data.linz.govt.nz). Analysis and visualisation: Toitū Te Whenua Land Information New Zealand.
While New Zealand has plenty of freshwater, we are heavy users of this resource. Our water use is changing the mauri of the streams, rivers and lakes in many parts of the country. Many regions have overallocated freshwater or are close to doing so, and in many catchments environmental bottom lines for contaminants are being exceeded.
Water resource models that help predict freshwater quantity and quality are important tools for decision makers to make robust, evidence-based management decisions on issues like contaminant discharges and water takes.
In this report, A review of freshwater models used to support the regulation and management of water in New Zealand, the Commissioner has investigated how models are being used by councils across New Zealand in freshwater management.
The report found that freshwater modelling in New Zealand is fragmented, under-resourced, under-supported and lacking leadership, with many gaps, overlaps, inefficiencies and inconsistencies in modelling between councils. It also revealed that there is a lack of commitment to, and investment in, mana whenua developed models and associated processes to involve mana whenua in the development and application of freshwater models.
The Commissioner is recommending several actions to improve freshwater modelling in New Zealand:
- the establishment of a national freshwater modelling support centre to provide guidance and practical advice to regional councils, unitary authorities and mana whenua
- further development of national guidance on the use of models in a regulatory context
- the establishment of a rōpū of experts to support the development and implementation of Māori freshwater models
- the evaluation of existing freshwater models against guidance
- the development of a preferred suite of models adaptable to local circumstances.
Correction
After the release of this report, the consultant's reports (Taylor, 2023) were modified by their author to remove one of the Māori freshwater models assessed and the related case study. As a result of these changes, consequential amendments have been made to PCE's water modelling report. The revised reports are published here.
Explore freshwater
Freshwater is essential to human wellbeing, our culture, environment and economy. Yet the state of this precious resource is fragile – both in quality and quantity. Find out more about about the Commissioner's work on freshwater.