NZ waterways: Not 100pct pure

NZ waterways: Not 100pct pure

We've heard a lot about the quality of our waterways; the decline of our rivers, lakes and aquifers has been picked up around the world and it is seriously denting our clean green image.

But a lot of people don't appreciate the connection between what is happening to our freshwater, and how that can affect our coastlines.

To be fair, it is quite a mental jump to think how dairy farm run-off could affect your dip in the ocean.

Our pristine beaches are not as clean as people realise and it is often unappreciated how sensitive saltwater can be.

Professor Russell Death from Massey University says it is like obesity.

"If you give estuaries too much sediments and nutrients and they can't deal with it – that is what is happening to a lot of our estuaries."

But how do these things get there?

Farming, construction and forestry all release sediment and nutrients into our environment and the more sediment you get, the more mangroves you get.

"Mangroves around New Zealand are increasing as a result of sediment," Prof Death says. "That's good because they provide a habitat for young fish, but at the same time we don't just want mangroves."

Last year the Government announced 14 percent of beaches monitored around New Zealand were classified high risk of causing illness or infection, and it's often what you cannot see that is causing the problem.

Prof Death says in places where there is industrial and urban development you will have heavy metals like copper, zinc and even arsenic going out into the waterways.

Another example is our motorways, used by hundreds of thousands of vehicles every day. Without proper collection systems, pollutants can wash straight off the roads into the waters.

But the huge problem is dairy farms.

The dairy herd has increased dramatically, up to six-and-a-half million. Each cow is producing the same amount of waste as 14 humans.

If you multiply that, you are left with the equivalent of 90 million people not using toilets, and whose excrements are flowing into our water.

Dairy farms aren't the only problem and there are solutions.

But the systems need to change to protect our waters, reputation and ultimately, our way of life.