Freshwater

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.

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.

Many New Zealand lakes are suffering from nutrient enrichment, causing potentially toxic blooms of blue-green algae. NIWA is testing a range of methods to manage phosphorus release from lake sediments – including sediment-capping agents.

Gathering, eating and sharing wild kai (food) has always been a very important part of Māori culture and wellbeing - this research project aimed to characterise the risks associated with consuming kai collected from rivers, lakes and coastlines.

This project involves the development of a computer-based framework for freshwater models. The framework will be tested to proof-of-concept stage.

NIWA has produced revised safe levels of dissolved oxygen for fish, which will help inform future environmental planning and resource consents and help to keep New Zealand rivers full of healthy fish.

Streams play a key role in the ecosystems of New Zealand’s unique landscape. They feed and link together freshwater sources, maintain good water quality and support habitats that sustain our biodiversity.

The giant kōkopu is a native whitebait species considered rare and vulnerable. NIWA is working with Mahurangi Technical Institute and environmental consultancy Boffa Miskell to test the feasibility of reintroducing giant kōkopu to Nukumea Stream, north of Auckland.

This project was undertaken for Auckland Regional Council to identify significant sources of contaminants in the central Waitemata and southeastern Manukau Harbours.