Reversing a drain on New Zealand’s wildlife

17 May 2018 by The Million Metres team Auckland Council Northland

If New Zealand wants to clean-up its waterways and beaches, we can’t carry on relating to waterways as if they were drains.



In urban areas like Auckland, big storms cause wastewater to overflow into stormwater drains. Everything that flows down a stormwater drain flows into waterways untreated. Some urban rivers effectively turn into toilets.

In rural areas like Canterbury, most of the lowland streams have been straightened out. They are managed by farmers as ‘drains’. That usually involves putting a digger in the stream to clear out waterweeds to ensure the drains don’t become clogged. It causes increases in sediment and habitat loss for freshwater fish. 

In urban areas, the solution will involve a combination of changes, including infrastructure upgrades to the stormwater and wastewater system. People will also need to be educated about harmful chemicals that shouldn’t go down drains.

In rural areas, organisations like Fish and Game, Environment Canterbury, as well as landowners are trying a different approach. For example, one project has begun that will reshape Silverstream, a tributary of the Selwyn River in Canterbury. It will no longer be a drain, but will once again become a thriving, living stream.

The Selwyn once supported some of the best trout fishing in the world. In 1962, it supported a run of 14,000 brown trout. Today, the estimate is around 500. Climate change, water takes and land intensification have contributed to this, including a loss of habitat in the spawning streams, such as Silverstream.

By reshaping and replanting the banks of Silverstream, the stability of the banks will improve. It will reduce the amount of soil washing into the water from erosion. Boulders, wood, and gravel will be added to recreate the natural pools that fish love. This will help increase the spawning of native fish and brown trout in the stream.

The project is located on Nathan and Jamie Fridd's dairy farm. They have owned the farm for three years. It was important to them that they restore Silverstream to a more natural state to help the fishery. Nathan is a keen angler himself.

The Fridd’s are fundraising to plant 2,040 native plants and trees along the stream. They are being supported by the Water & Wildlife Habitat Trust.

If you would like to support the project, click here.