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.

Rachel Crawford and Paul Franklin inspecting a fish passage on the Waikato River.

Freshwater and Estuaries Update

A seasonal review and outlook for New Zealand's water resources, and an update on NIWA's freshwater research

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  • Link to source page

    Lake Brunner water quality

    Research Project
    A project funded by West Coast Regional Council has increased our knowledge of the role of phosphorus in determining water quality in Lake Brunner.

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    In search of the giant kokopu

    Fisheries

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    Lake assessment tool earns high honour for NIWA scientist

    News article
    21 October 2011
    John Clayton, a principal scientist in the fields of aquatic biodiversity and biosecurity based at NIWA's Hamilton office, has won a 2011 Kudos award for his leading role in the development of LakeSPI  (Lake Submerged Plant Indicators).
    Lakes

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    Trout habitat mapping protocol

    Fisheries

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    Restoring riparian and instream cover

    Freshwater quality

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    Restoring flow

    Freshwater quality

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    Habitat loss

    Freshwater quality

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    Poor recruitment

    A problem with recruitment is usually indicated by the absence, or very low density, of fish where they would normally be present.
    Fisheries
    Freshwater quality

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    Restoring physical stream habitat

    Fish species thrive in a variety of different habitats.
    Freshwater quality

  • Link to source page

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    Guide to restoring freshwater native fish in streams

    Fisheries
    Freshwater quality

  • Link to source page

    Lake Rotorua sediment-capping trial

    Research Project
    Many New Zealand lakes are suffering from nutrient enrichment, causing potentially toxic blooms of blue-green algae. NIWA is testing a range of methods to manage phosphorus release from lake sediments – including sediment-capping agents.

  • Link to source page

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    CLUES – Catchment Land Use for Environmental Sustainability model

    The Catchment Land Use for Environmental Sustainability (CLUES) model is being transferred from the ArcMap GIS environment to ArcGIS Pro and we are looking for volunteers to help test the new model interface with a limited Beta release of the model.