Freshwater quality

How healthy is your stream? SHMAK - the New Zealand Stream Health Monitoring and Assessment Kit - has been designed to help you find out.

One of the most common species of freshwater fish in Aotearoa is the common bully or toitoi.

How do nutrients from wastewater treatment enter waterways?

Dissolved oxygen (DO) is a relative measure of the amount of oxygen (O2) dissolved in water.

Tuna or freshwater eels are a very significant, widely-valued, heavily-exploited, culturally iconic mahinga kai resource.

NIWA provides national capabilities in Water Quality Monitoring

A high proportion of New Zealand’s native freshwater fish fauna need to migrate to and from the sea.

Nutrients in waterways are essential for the growth of algae and aquatic plants but too much can destroy an ecosystem.

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