The Front Page: The filthy truth about New Zealand’s longest river

At Tuakau tiny particles of dirt fill the water. Photo / RNZ

Swimmers are gambling with their health when they dip into some parts of the Waikato River.

RNZ data journalist Farah Hancock tells the Front Page podcast that those who swim near the Tuakau Bridge face a significant risk of suffering health effects due to infection from faecal matter.

She says that between 20 to 30 per cent of the time, more than 50 of every 1000 people who participate in the sport are likely to fall ill.

The good news is that there is a plan to clean the river and ensure that it is again safe for swimming and fishing.

The catch is that the current generation of Kiwis is unlikely to see this plan reach its conclusion.

Waikato Regional Council has confirmed a plan to restore the entire length of the river, but it’s expected to take until 2096 – more than 70 years from today.

“In some ways, that figure is a line in the sand,” says Hancock.

“If we don’t have a date to work with, then it will just keep getting pushed up. That plan also acknowledges that if we are going to clean the river, we’re going to have to change the way we’re using the land around the river. That is going to take time. That’s not something that can happen overnight.”

Hancock says the river is currently contaminated with four contaminants, which are cause for concern.

“There’s nitrogen and phosphorus, and in excess that can cause excessive plant growth – which can lead to toxic algae blooms.

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Another contaminant is sediment, which are little bits of dirt that flow into the river from the surrounding land. Sediment isn’t good for fish. It can stop them from seeing and being able to find food or get to places. It can also get into their gills and act a bit like sandpaper … And the final one is e.coli, which is basically poo and can come from animals or humans.”

Hancock says that much of the damage being caused comes down to how the land around the river is being used.

“I like to split the causes into those that are visible and invisible,” says Hancock.

“I think when most people think about pollution in rivers, they think of the pipes jutting out from sewage or wastewater plants, jetting water into the river. That’s called point source. Along the river there are sewage plants, there’s a dairy factory, meat works, and a pulp and paper mill. They do put contamination into the river.”

She adds, however, that the other sources of contamination aren’t as obvious to the average observer.

“The invisible contamination involves nutrients and phosphorus leaching from the land around the river. There’s a lot of intensive dairying to the bottom of the river – and what happens is cows on the land can pee or fertiliser can be put on the land and that can leach through the ground, slowly draining into the river.”

In doing her research, Hancock said that the thing that surprised her most was that the majority of the contamination was coming from land use rather than any industries putting waste into the river.

“For nitrogen, it was 61 per cent coming from land use, versus 6 per cent coming from wastewater from industries.”

Hancock says the reason for the long timeline is three-fold: Firstly, it will be a long process to change the way land is used in these areas; secondly, there’s a lag that occurs between nitrogen seeping into the soil and then leaching into the water; and thirdly we don’t have the technology to fix this problem quickly.

This all means that small incremental changes in land use will have to happen over time in order to repair the environment in the coming decades.

Hancock says that some members of the farming community are already on board with moving toward systems that will help to improve the water quality.

“I don’t think any farmer would say they don’t want the river to be safe to swim in or take food from,” says Hancock.

“Rick Burke, the chairperson for Farmers for Positive Change, is very much in favour of what’s in the plan. And one thing he said to me was that all farmers must take responsibility for what leaves their farms. He says a farm is a business and you need to take responsibility for the nitrogen that leaches from it. And I think that’s going to be key to helping clean the river.”

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The Front Page is a daily news podcast from the New Zealand Herald, available to listen to every weekday from 5am. • You can follow the podcast at nzherald.co.nz, iHeartRadio, Apple Podcasts, Spotify, or wherever you get your podcasts.

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The Front Page is a daily news podcast from the New Zealand Herald, available to listen to every weekday from 5am.

• You can follow the podcast at nzherald.co.nz, iHeartRadio, Apple Podcasts, Spotify, or wherever you get your podcasts.