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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Research

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    DSS for setting turbidity limits at base flows

    DSS for setting turbidity limits at base flows

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    DSS for setting turbidity limits at peak flows

    DSS for setting turbidity limits at peak flows

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    Predicting long-term contaminant accumulation in the central Waitemata and southeastern Manukau Harbours

    Research Project
    This project was undertaken for Auckland Regional Council to identify significant sources of contaminants in the central Waitemata and southeastern Manukau Harbours.
    Coasts
    Ocean modelling
    Pollution

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    Stocktake of diffuse pollution attenuation tools for New Zealand pastoral farming systems

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    Estimating deposited fine sediment

    Quorer: a simple method for estimating deposited fine sediment

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    Setting maximum turbidity levels for riverine fish (DSS)

    NIWA research has established turbidity limits to protect fish in New Zealand rivers.

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    Models to help manage erosion

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    Freshwater management tools

    Some of the useful methods, guidelines and modelling tools we've developed to assist with management of freshwaters.

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    Freshwater species and habitat management

    Find out how we can help you with freshwater species and habitat management.

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    Flow assessment and management

    We offer a range of flow assessment and management services.

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    Wastewater treatment

    We can help with wastewater treatment and ecotoxicology.

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    Water quality monitoring and advice

    More information about our water quality monitoring and advice services.