On 1 July 2025, NIWA merged with GNS Science to become Earth Sciences New Zealand.

Freshwater

We provide public information on river, lake, and groundwater conditions across New Zealand including freshwater quantity and quality.

  • Nature knows best?

    Feature story
    Returning water to our waterways after we’ve used it in our homes, on farms and in industry is a complex and challenging process.
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    Electric Fishing Machine - NIWA EFM300

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    Tuna - elvers and recruitment

    Once in freshwater, glass eels develop into darker pigmented juvenile eels known as elvers.
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    Horticultural activities

    Land is tilled, sowed, and harvested for horticultural crops to grow.
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    Riparian management classification

    Management of stream riparian areas - including vegetation and stock access - influences the health of streams and downstream water bodies.
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    Infectious substances

    Waterways can easily become contaminated by pathogens when effluent is discharged nearby.
  • Chemical contamination and agriculture

    What are the potential sources of chemical contamination from agricultural activities?
  • Urbanisation

    Aotearoa’s main urban areas cover approximately 2% of total available land.
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    Summer Series 8: The forces behind beach ‘foam’

    News article
  • NZ Freshwater Fish Database Help

    Learn how to use the New Zealand Freshwater Fish Database (NZFFD)
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    Proud of your plants? 1 June 2017

    News article
    NIWA is doing a nationwide study to discover what makes the best riparian projects. Help us give you the knowledge to make the best riparian management decisions possible by taking our 5 minute survey.
  • Mangroves: to clear or not to clear?

    Media release
    NIWA scientists have written a guide for managing mangroves, prompted by a desire for people to learn more about mangrove ecosystems, and what happens when they are removed.