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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    Chemical contamination and urbanisation

    What are the sources of chemical contamination resulting from urbanisation?

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    Riparian vegetation and horticulture

    How may horticultural activities impact riparian vegetation around a waterway?

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    Water resources and horticulture

    How do horticultural activities potentially influence water flows?

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    Chemical contamination and horticulture

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

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    Nutrients and horticulture

    What are the potential sources of nutrients from horticultural activities?
    Freshwater quality

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    Sediment and horticulture

    How may horticultural activities increase sediments in waterways?
    Freshwater quality

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    Instream barriers and forestry

    How do instream barriers as a result of forestry activities potentially influence water resources?

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    Riparian vegetation and forestry

    How may forestry activities impact riparian vegetation around a waterway?

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    Chemical contamination and forestry

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

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    Nutrients and agriculture

    What are the potential sources of nutrients from agricultural activities?
    Freshwater quality

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    Discharges

    Discharging into a waterway is likely to impact water quality.

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    Dissolved oxygen criteria for fish

    Research Project
    NIWA has produced revised safe levels of dissolved oxygen for fish, which will help inform future environmental planning and resource consents and help to keep New Zealand rivers full of healthy fish.