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.

  • Running off the road

    Feature story
    At a rough count, 700 million litres of rain runs off the nation’s roads every year. That’s enough water to fill almost 300 Olympic-sized pools.
  • Beautiful Browns

    News article
    Do you know where in New Zealand to find Neptune’s necklace or rimurapa? Or how to tell apart Carpophyllum from Cystophora?
  • Mercury biomagnification in three geothermally-influenced lakes differing in chemistry and algal biomass

    Research Project
    This research project aimed to understand the causes behind differences in mercury in trout and other organisms in the Bay of Plenty/Te Arawa lakes—in particular what features of each lake explain why mercury in trout is higher in some lakes than in other lakes.
  • Flow requirements for galaxiid fish spawning

    Research Project
    Many of our iconic native fish species, such as whitebait and eels, rely on river flows to cue key life-cycle stages, including migration and reproduction. As pressures on water resources increase, the risk of disrupting these flow cues, and therefore impacting fish populations, becomes greater.
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    Case study example: Bankwood (Kukutaruhe) Stream, Hamilton

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    Baffle design

    Baffle design to facilitate fish passage through culverts
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    Ramp design

    Ramp design to facilitate fish passage
  • Understanding fish passage in New Zealand

    Research Project
    NIWA scientists have been investigating the different capabilities of our native freshwater fish species in order to help design effective solutions for overcoming barriers to migration
  • Tau kōura sample collection and processing protocol

    Tau kōura is a traditional Māori fishing method commonly used to harvest kōura or freshwater crayfish in areas where they are abundant.
  • Report on Waikato and Waipa rivers sets benchmark

    Media release
    A whole of catchment Report Card for the Waikato and Waipa rivers has been released by the Waikato River Authority giving the catchment an anticipated low rating for its wellbeing.
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    NIWA completes first bathymetric mapping of Lake Tekapo

    Media release
    NIWA researchers have spent part of the last month keeping a close eye on the bottom of Lake Tekapo to find out what it looks like and what is going on below the lake bed.
  • New Zealand's best job?

    NIWA environmental monitoring technicians Evan Baddock and Eric Stevens venture deep into Fiordland, NZ to monitor river and lake levels in the area.