Rivers

Latest news

It may be rubbish to everyone else, but to Amanda Valois each little scrap of plastic on a river bank or in a waterway tells a valuable story.
Christchurch’s Red Zone is to be the focal point of a scientific experiment involving street lights and insects over summer. 
On the bottom of New Zealand’s largest freshwater springs is an underwater garden of vivid green, pinks and inky blues.
As the road behind Hanmer Springs turns to gravel and a dust cloud forms in the rear vision mirror, the southern edge of Molesworth Station unfolds.

Our work

New Zealand’s freshwater and estuarine resources provide significant cultural, economic, social, and environmental benefits. Competition for the use of these resources is intensifying, and many rivers, lakes and estuaries are now degraded. Māori are particularly sensitive to the use and development of freshwater, and hold distinct perspectives concerning their identity, knowledge, and custodial obligations to manage tribal waters.

NIWA is developing numerical models for predicting how the morphology of braided rivers responds to flow regulation and invasive exotic woody vegetation.

Most of the plastic in the ocean originates on land, being carried to the estuaries and coasts by rivers. Managing this plastic on land before it reaches the river could be the key to stemming the tide of marine-bound plastics. The aim of this project is to understand the sources and fate of plastic pollution carried by urban rivers using the Kaiwharawhara Stream as a case study.
The New Zealand Fish Passage Guidelines sets out recommended practice for the design of instream infrastructure to provide for fish passage.

Latest videos

A day out measuring at Molesworth
A day out measuring at Molesworth
Modelling vegetation-impacted morphodynamics in braided rivers
NIWA is developing numerical models for predicting how the morphology of braided rivers responds to flow regulation and invasive exotic woody vegetation.
This project aims to increase our knowledge of aquatic ecosystems and their restoration, and apply this to degraded streams, rivers, lakes and estuaries.

The New Zealand Water Model (NZWaM) – a new water modelling approach

Models have an important role to play in water management in New Zealand.

 To be useful, models need to be both flexible and complex; flexible because they are needed for a wide range of purposes, and complex because they need to simulate complex natural and man-made systems (Figure 1). Ideally, these models will have a modular design, so that sub-models that represent hydrological, climatic, water quality, ecological and other processes can be added. 

Scientists make break-through in saving freshwater mussels

Doctoral student, Michele Melchior, has made an important breakthrough in the effort to save New Zealand's freshwater mussels, or kākahi.

Michele’s PhD study is part of the Cultural Keystone Species research programme, which is funded by the Ministry of Business, Innovation and Employment.

Michele has discovered that the different mussel species have different reproductive strategies and that the population of one species is declining faster than its counterparts. This clue could essentially help prevent the species decline.

Glass eel ear bones could reveal migration patterns

The ear bones of tiny eels might hold clues to their largely secret life.

NIWA freshwater ecologist Dr Eimear Egan hopes that a three-year research project will help reveal the secret life of eels, where they go and why. 

The project might also reveal their migratory habits from New Zealand rivers across vast areas of the ocean, and the effects of climate change in the ocean. 

Most of the plastic in the ocean originates on land, being carried to the estuaries and coasts by rivers. Managing this plastic on land before it reaches the river could be the key to stemming the tide of marine-bound plastics. The aim of this project is to understand the sources and fate of plastic pollution carried by urban rivers using the Kaiwharawhara Stream as a case study.
It may be rubbish to everyone else, but to Amanda Valois each little scrap of plastic on a river bank or in a waterway tells a valuable story.
Christchurch’s Red Zone is to be the focal point of a scientific experiment involving street lights and insects over summer. 
The Fish Passage Assessment Tool has been developed to provide an easy to use, practical tool for recording instream structures and assessing their likely impact on fish movements and river connectivity.

The issue

Currently there are gaps in understanding of user decision making processes and public needs and requirements for river forecasting in New Zealand. This project aims to bridge NIWA river forecasting aspirations and capabilities with both the public and decision makers’ requirements. This project addresses the following question: How do we better align our current and planned river forecasting capabilities and interactions with users and decision makers’ requirements? 

Freshwater Update 79 brings you the latest information from our Freshwater & Estuaries Centre, with articles ranging from NIWA working with NASA; restoring a stream catchment in Kaikōura; looking after urban water; keeping soil and reducing sedimentation; to culling catfish.

‘Swimmability’ of New Zealand rivers

Swimming is a popular activity in Aotearoa-New Zealand. Two attributes of waters that strongly affect aesthetic quality and safety for swimming are visual clarity and faecal contamination. It turns out that these two attributes are fairly well-correlated (inversely) in New Zealand rivers, such that (easily seen) visual clarity provides a rough-but-useful guide to (unseen) microbial quality.

The value of archived biological collections: understanding the lake snow invasion

The diatom (Lindavia intermedia) that causes lake snow—nuisance slime in clean-water lakes that ruins angling and can block water intakes—was apparently introduced to New Zealand shortly before 2002, but was widespread by 2005. To obtain a clearer picture of when this diatom arrived in New Zealand, Otago Regional Council (ORC) commissioned NIWA to search archived diatom data and collections.

Freshwater Update 78 brings you the latest information from our Freshwater & Estuaries Centre, with articles that cross a broad spectrum of freshwater research, from archives to aquifers, periphyton guidance, geo-engineering and swimmability.

On the bottom of New Zealand’s largest freshwater springs is an underwater garden of vivid green, pinks and inky blues.
The New Zealand Fish Passage Guidelines sets out recommended practice for the design of instream infrastructure to provide for fish passage.
Freshwater Update 76 brings you the latest information from our Freshwater & Estuaries Centre, with articles ranging from spring and river water condition to urban waters, didymo and aquatic plant scientists.
As the road behind Hanmer Springs turns to gravel and a dust cloud forms in the rear vision mirror, the southern edge of Molesworth Station unfolds.
A day out measuring at Molesworth
A day out measuring at Molesworth
NIWA is undertaking a five-year nationwide study to find out how different approaches to riparian planting influence water quality improvements and to provide better guidance to the people and groups undertaking stream restoration.
Returning water to our waterways after we’ve used it in our homes, on farms and in industry is a complex and challenging process.

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All staff working on this subject

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Hydro-ecological Modeller
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Freshwater Hydro-Ecologist
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Riparian and Wetland Scientist
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Land and Water Scientist
Assistant Regional Manager - Christchurch
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Freshwater Fisheries Ecologist
Principal Scientist - Aquatic Pollution
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Hydrology Scientist
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Environmental Monitoring Technician
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Freshwater Ecologist
Environmental Monitoring Technician
Hydrodynamics Scientist
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Urban Aquatic Scientist
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Environmental Scientist
Algal Ecologist
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