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Managing our estuaries

11 August 2020

NelsonNZ, Flickr

The Commissioner is calling for an approach to managing estuaries that treats estuaries and the waterways that feed into them as a single entity from the mountains to the sea, ki uta ki tai.

Estuaries receive and accumulate large amounts of whatever is emptied into them. Yet they fall between the cracks of our siloed management.

This report uses five estuaries as case studies to illustrate some of the environmental challenges they face, and how they are managed.

It finds that estuary management is not about managing the body of water itself but rather about managing the activities that affect it.

As many of the pressures that impact on estuaries arrive via the freshwater systems that feed them, the Commissioner recommends that every estuary be included in one or more freshwater management units within the National Policy Statement for Freshwater Management 2020.

This would ensure that the relatively comprehensive and robust management regime that applies to freshwater management units covers all estuaries.

The Commissioner also recommends establishing a robust monitoring system to help local government and communities make informed decisions. Ideally, this would be standardised, independently assessed and include metrics based on mātauranga Māori.

This should apply to all the pressures that cumulatively impact on estuaries, as well as to estuaries themselves.

More information on estuaries


To view the generic estuary model, please first download Netica software from www.norsys.com/download.html.


Our estuaries are special places but many are suffering from the things we do in and around them.

Watch the animation, Estuaries: Waste traps or taonga?


  • Resources

    Managing our estuaries (PDF 4.4 MB)
    Download Request content
    FAQs – Managing our estuaries (PDF 82 KB)
    Media release – Managing our estuaries (PDF 76KB)
  • Consultant reports

    Generic estuary model with cumulative pressures (NETA 277KB)
    Exploring the impact of multiple stressors on estuarine ecosystems using a Bayesian network model (PDF 4.6MB)
    Notes on 'Exploring the impact of multiple stressors on estuarine ecosystems using a Bayesian network model' (PDF 230KB)
  • Related resources

    Managing water quality (PDF 1.06 MB)
    Update report – Water quality in New Zealand: Land use and nutrient pollution (PDF 950 KB)
    Update report – Water quality in New Zealand: Understanding the science (PDF 301 KB)