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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    Sediment and forestry

    How may forestry activities increase sediments in waterways?
    Freshwater quality

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    Chemical contamination

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

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    Cropping activities

    The land used to produce crops is usually flat to gently rolling so it can be tilled, sowed, and harvested.

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    What do we measure?

    Research Project
    A range of physical and chemical variables are measured in the NRWQN.
    Freshwater quality

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    Dissolved oxygen

    Dissolved oxygen (DO) is a relative measure of the amount of oxygen (O2) dissolved in water.
    Freshwater quality

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    Impacts of wood processing

    Impacts of timber processing activities on water quality and mahinga kai.

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    Riparian vegetation and agriculture

    How may agricultural activities impact riparian vegetation around a waterway?

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    Mahinga kai - what species interests you?

    In Kaitiaki Tools the term mahinga kai generally refers to indigenous freshwater species that have traditionally been used as food, tools, or other resources.
    Freshwater quality

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    Chemical contamination and aquaculture

    What are the potential sources of chemical contamination from aquaculture activities?
    Aquaculture

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    Chemical contamination and mining

    What are the potential sources of chemical contamination from mining activities?

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    Further reading

    References, further reading, and links to useful websites.
    Freshwater quality

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    Loss of riparian vegetation

    Plants and trees along the water margins and banks are called riparian vegetation.