From our Chair: Keeping nasties out of stormwater

Imagine taking a bottle of detergent down to your local stream, opening the lid, and pouring the contents straight into the water – into the habitat of fish and other creatures.

Of course, you wouldn’t do this. But did you know that a lot of the everyday things we do can have similar effects. When large portions of communities do these things, it can negatively impact the health of our rivers, streams, and bays.

For instance, when you wash your car on the driveway, the run-off that goes down the stormwater grate usually goes straight to waterways.

While most people don’t give stormwater a second thought in their daily lives, I’m hoping I can convince you to look at the topic in a new light.

Increasing awareness around stormwater

In fact, you may have seen some recent ads encouraging people to be a Stormwater Superhero.  

If you didn’t know that stormwater grates almost always lead directly to waterways (particularly in urban Christchurch), then you’re not alone.

A 2018 Christchurch City Council survey found close to half of the respondents either didn’t know where stormwater flowed to or thought it went to a treatment plant.

Unfortunately, it’s just not feasible to treat it all – which is why it’s so important that we all do our bit to keep things like litter, paint, metals, plastics, chemicals, and animal poo out of our stormwater drains.

Contamination from vehicles 

The amount and number of contaminants that end up in rivers and streams is quite astonishing.

For instance, each year around 31 tonnes of zinc and 4.5 tonnes of copper enter the Heathcote, Avon, Styx, and Halswell rivers.

A stormwater outlet in the Avon River/Ōtakaro awa

A stormwater outlet in the Avon River/Ōtakaro awa

Vehicles are a big contributor. When you pump the brakes, fine particles of copper fall onto the road. When it rains, these shavings get washed into the stormwater system – along with zinc from tyre wear.

The United States is taking the matter of reducing the amount of copper in brake pads seriously, passing laws in California and Washington.

In 2015, the U.S. automotive industry and the U.S Environmental Protection Agency signed a voluntary agreement to roll out similar measures.

I fear other countries, including New Zealand, are dragging their heels on the issue.

Christchurch mayor Lianne Dalziel and I recently wrote to the government, calling for more action. We want further analysis undertaken to better understand the practicalities of implementing such a policy – and we’re asking to meet with officials on the matter.

In the meantime, I encourage you to look at your own backyard – literally – and think about ways you can help keep our waterways clean.

Good practice starts at home

Washing your car on grass or gravel is a good start, as this absorbs the detergent. Keep your vehicle well maintained, including checking for oil leaks.

When doing DIY, rinse your paintbrushes in the laundry sink, not directly into the stormwater drain. Sweep up things like sawdust and soil around your property.

Always pick up after your dog. E. coli from animal poo is a big contributor to stormwater pollution.

For more tips, have a read of our stormwater page.

I believe everyone has an ethical duty to help the environment, and it starts at home. If we all make small changes, the results can be huge.

Let’s not let the health of our waterways go even further down the drain.