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.

  • Ecotoxicology services

    Service
    NIWA offers a range of standard toxicity tests for both freshwater and marine environments.
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    Water clarity

    Water clarity or turbidity is the cloudiness or haziness in a fluid caused by individual small particles (suspended solids).
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    Tuna - spawning grounds

    All species of freshwater tuna spawn at sea, although the spawning grounds of only four species are known with certainty worldwide.
  • Chemical contamination

    Chemical contaminants are chemicals toxic to plants and animals in waterways.
  • Pulp and paper

    Wood chips and plant material make pulp that is used to produce paper products.
  • Dry stock

    Dry stock farming consists predominantly of pasture grazing beef cattle, sheep, and deer for meat, wool, and velvet production.
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    New Zealand rushes (Juncus): factsheets and key

    New Zealand rushes (Juncus): species-level factsheets.
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    Mining activities

    A range of different mining techniques have been developed to obtain these valuable resources
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    Mitigation and best practice options

    Some simple steps to minimise the effects of mining activities on water quality and mahinga kai.
  • Chemical contamination and wood processing

    What are the sources of chemical contamination from wood processing?
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    Impacts of water dams

    What are the impacts of water dams on water quality and mahinga kai?
  • Development of sustainable water supply and treatment systems for a coastal Fijian village

    Research Project
    This collaborative NZaid project worked with coastal Fijian villagers at Votua on the Coral Coast of Viti Levu to develop pragmatic water supply and waste treatment solutions to protect public health and reduce contamination of coastal waters.