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.

  • NELSON MAIL: Blue Lake a New Zealand treasure

    Media release
    Water in the Blue Lake is the clearest freshwater ever reported.
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    Lake sediments reveal frequency of Hawke’s Bay quakes

    News article
    An international team of scientists has analysed 7000 years’ worth of lake-bottom mud from central Hawke’s Bay to work out how often the region might expect earthquakes.
  • Summer Series #5: A helping hand

    News article
    Te Waihora is a special lake in need of some intensive care. Together, scientists, iwi, locals and environmentalists are pooling their knowledge and resources to make it better.
  • NIWA ecologists catch on to a bug's life

    News article
    Kneeling in the mud under the cover of trees, covered in anoraks, sandflies and dedication, three scientists are looking out for the little guy.
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    Climate change freshwater impacts assessments

    New Zealand’s climate is changing – and so are our freshwaters.
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    Scientists make rare find in Auckland streams

    News article
    NIWA and Auckland Council freshwater scientists using fish pheromone samplers have made a rare discovery in two Auckland streams.
  • CHES - smarter use of New Zealand’s river waters

    CHES (Cumulative Hydrological Effects Simulator) software tool predicts how water flows in a catchment will change with multiple water uses (e.g. direct abstractions or storage reservoirs) and what the consequences will be to in-stream ecosystems and reliability of water-take.
  • Binding Phosphorus

  • Constructed Wetlands

  • Riparian Zones

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    C-CALM: modelling annual contaminant loads to inform stormwater planning and management

    NIWA’s Catchment Contaminants Loads Model (C-CALM) is a spatial decision support system for planning applications. It estimates annual contaminant loads at the neighbourhood to stormwater management unit (sub-catchment) scale, from diffuse sources, for Total Suspended Solids (TSS) and particulate and dissolved zinc and copper. The estimated load is then adjusted for water treatment.
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    Summer Series Week 4: When aliens attack

    News article
    Your favourite lake may look picturesque, calm and inviting but beware what lurks beneath – aliens are on the attack.