Freshwater and Estuaries research projects

Read more about our freshwater and estuaries research. 

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.

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

Three plants of an endemic submerged quillwort (Isoëtes) were recovered from Lake Ōmāpere by NIWA in 1998, prior to the lake weed (Egeria densa) dying off and the lake switching into an algal dominated turbid state. No further isoëtes plants have been observed in the lake since that time.
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.
Last updated: 
4 October 2016
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.

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.

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.
The ability to properly manage our freshwater resources requires a solid understanding of the flora and fauna which live in and interact with them.
Last updated: 
26 February 2014
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.
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.
Mangrove forests, which are important parts of estuarine ecosystems in a number of ways, are sensitive to changing sea level.
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.
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.
New Zealand's geographic isolation and relatively recent colonization provide the opportunity for a unique genetic analysis of plant movement patterns to be explored.
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.
A significant threat to the biosecurity of New Zealand's freshwater habitats comes from plants that have been intentionally introduced.
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.
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.
A project funded by West Coast Regional Council has increased our knowledge of the role of phosphorus in determining water quality in Lake Brunner.
Last updated: 
14 March 2017

How will water resources in the water-limited parts of New Zealand, such as Canterbury and Hawkes Bay, look in the future?