Freshwater quality

The tools available for restoring kōura to lakes and streams depend on what is causing kōura to decline.

First, determine if kōura should be present in your stream.

Identifying the factors causing kōura numbers to decline will allow you to determine which restoration tools you need to employ.

Habitat degradation and the introduction of exotic plant and fish species have adversely affected kōura populations throughout New Zealand. However, there are a number of measures that we can use to restore kōura populations in lakes, rivers and streams.

New research has revealed that citizen science monitoring of water is a win-win for scientists and volunteers—one gains access to new data, and the other the skills and confidence to become involved in discussions over what is happening to their streams.

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.

A NIWA study has shown that environmental factors influence the level of mercury in fish and other organisms in lakes in New Zealand's North Island geothermal area

NIWA’s Catchment Contaminants Loads Model (C-CALM) is a spatial decision support system for planning applications. It estimates annual contaminant loads at the neighbourhood to stormwater management unit (sub-catchment) scale, from diffuse sources, for Total Suspended Solids (TSS) and particulate and dissolved zinc and copper. The estimated load is then adjusted for water treatment.

These are some recent publications related to the causes and effects of water quality degradation programme.

Understanding and predicting the sources of contaminants, developing technologies to clean up the sources, and understanding the consequences of water quality degradation for aquatic ecosystems and human use of 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.