Freshwater and Estuaries research projects

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Read more about our freshwater and estuaries research. 

Flow requirements for galaxiid fish spawning

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.

Understanding fish passage in New Zealand

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

Recovering plants for reintroduction to Lake Ōmāpere

NIWA recently hosted visitors from Northland to view cultivated plants from Lake Ōmāpere that are now ‘extinct in the wild’, and discussed plans for their reintroduction to the lake in the future. 

Waitaki weed surveillance plan

NIWA and Meridian are developing a management strategy on LINZ crown owned lakes for pest aquatic plants – weeds, the alga Didymosphenia geminata (Didymo) and filamentous green algae (both native and introduced) - in the Waitaki Catchment.

Biofilms in groundwater systems

Biofilms – communities of microorganisms growing together – are common in groundwater systems, but we don't know much about them. Our scientists devised a series of studies to start to understand what environmental changes they can cope with and still play their role in a healthy groundwater ecosystem.

Modelling channel dynamics in braided rivers

NIWA are contributing to and testing the open source Delft3D model so that it can be used to simulate the response of braided rivers and their ecosystems to the changes in river flow associated with water use schemes, such as dams.

Freshwater monitoring and reporting

NIWA's research on freshwater monitoring and reporting is one of three research areas within the 'Values, Monitoring and Outcomes' (VMO) programme led by Landcare Research.

Mapping our freshwater biodiversity

The ability to properly manage our freshwater resources requires a solid understanding of the flora and fauna which live in and interact with them.

Small waves in estuaries

We know that waves cleanse estuaries of silts and clays, keeping intertidal flats sandy and healthy. But how big do waves have to be to be effective in this way? New research shows that very small waves can be just as effective as big waves.

Tidal creeks – connections between freshwater and saltwater

An experiment in Henderson Creek, Auckland, has demonstrated how tidal creeks variously import, export and deposit sediment, depending on the wind and freshwater runoff, and modulated by the tide.

Sediments and mangroves

Mangrove forests, which are important parts of estuarine ecosystems in a number of ways, are sensitive to changing sea level.

Staying ahead of water weed invasions

Aquatic systems are under threat due to the introduction of invasive exotic species such as water weeds. Modelling work by NIWA has provided new information on which water bodies may be at greatest risk.

Fish risk assessment

NIWA has developed a rapid, desktop model which assesses the potential impact of introducing new fish species to New Zealand. The model is customised to New Zealand's unique environment and endemic fish.

Globalisation of aquatic plant pests

New Zealand's geographic isolation and relatively recent colonization provide the opportunity for a unique genetic analysis of plant movement patterns to be explored.

Sedimentation in New Zealand estuaries

Estuaries in New Zealand are experiencing sedimentation at higher rates than before humans arrived here: this represents a loss both for land and estuary productivity. We need to better understand what has been happening so that we can predict the future and fight these losses.

Aquatic weed risk assessment model (AWRAM)

A significant threat to the biosecurity of New Zealand's freshwater habitats comes from plants that have been intentionally introduced.

Tracking river plumes

River plumes form one of the primary connectors between river-estuary systems and the coastal ocean.

Controlling water weeds with grass carp

A Ministry for Primary Industries-funded study has shown that grass carp, in enclosures, can be used as an effective means of controlling invasive plant species in our waterways.

Waikato River Independent Scoping Study (WRISS)

Many of New Zealand's aquatic ecosystems, and their services, are in a degraded and often worsening state. NIWA is involved in research and consultation' aimed at improving the health of our freshwater systems.

Lake Brunner water quality

A project funded by West Coast Regional Council has increased our knowledge of the role of phosphorus in determining water quality in Lake Brunner.

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