Avon River/Ōtākaro catchment

We, through the Christchurch West Melton Zone Committee, have been working with residents, businesses, and other interested parties within the catchment since 2014 to improve the waterway's health.

Key actions taken:

• Increased in catchment water quality monitoring to understand ‘hot spots’ of contaminants
• Increased community awareness of stormwater protection, the stream and its challenges
• Partnering with the University of Canterbury who modelled contaminant loads from different surfaces e.g. roads, roofing and carparks to guide most effective treatment
• Workshop with community and interested parties to create a vision and solutions for the catchment
• Development of Addington Brook Catchment Management Plan

To find out more, read this Water NZ report.

The Addington Brook catchment sits within the Christchurch West Melton zone of the Canterbury Water Management Strategy (CWMS). The vision for the zone is for its urban waterways to be healthy and for its communities to have a potable supply of untreated groundwater into the future.

Christchurch City Council is currently working on a two-stage enhancement project: stage one is complete, and stage two is expected to finish in mid-2025.

The enhancement project focuses on removing items in the brook that currently impede water flow during storm events, planting native trees along the berm to increase biodiversity, and eventually connect with a stormwater filtration system which improve water quality in Addington Brook.

Christchurch City Council (CCC) is responsible for the stormwater network in Ōtautahi and they currently hold several stormwater discharge consents with us. Water quality monitoring is undertaken for both consent compliance and state of the environment reporting, and the results are published on an annual basis. CCC has been monitoring the water quality in Addington Brook monthly since 2007.

Each water quality test gives us a snapshot of the water quality at a particular point at a particular time. Because streams are constantly flowing, their water quality can be in constant flux.

When samples are taken over a prolonged period, using a consistent approach, our water quality scientists can build up a picture of what the overall water quality in a stream is like. Analysis of the data reveals trends and patterns that give an indication of how good or bad the water quality is, where contaminants might be coming from, and how likely the water is to be able to sustain life.

Stormwater is water that runs off our roofs, driveways, footpaths, roads, and gardens. On its journey to the drain, it picks up a heap of contaminants (pollution).

Many people don’t realise that in urban areas of Waitaha/Canterbury, stormwater usually flows untreated into our rivers and streams and out to sea.

Common pollutants include substances like litter, animal poo, sawdust, spills, soil, and chemicals from things like washing cars on our driveways and rinsing paintbrushes down the stormwater drain.

Ultimately, these nasty contaminants end up washing into our rivers and waterways, like Addington Brook, where they harm or kill fish, insects, and plant life - ruining habitats.