Freshwater quality

Waterways can easily become contaminated by pathogens when effluent is discharged nearby.

The condition of many NZ lakes is under threat from land-use changes and the invasion of alien aquatic plants.

Banded kōkopu juveniles are very good climbers and will try to escape from buckets by clinging to and wriggling up the sides.

When soils erode, sediments are washed into waterways.

Submerged plants have a number of advantages that favour their use as indicators of lake ecological condition.

The largest member of the Galaxiidae family.

Find out more about emergent aquatic plants.

NIWA discusses, in depth, this year's most asked question—what is happening to our fresh waterways?

Inanga are the predominant species in the modern whitebait fishery.

Temperature affects the number and type of animals and plants that live in a waterway.

Returning water to our waterways after we’ve used it in our homes, on farms and in industry is a complex and challenging process.

The kākahi or freshwater mussel was a valuable mahinga kai resource for many Māori.