Water quality getting worse – report

  • 21/10/2015

By Sarah Robson

Water quality in some of New Zealand's rivers is getting worse, according to a new report card on the state of the environment.

But Environment Minister Nick Smith says farmers can't take all the blame and both town and country need to do better.

The Environment Aotearoa 2015 report – independently put together by Statistics New Zealand and the Ministry for the Environment – paints a mixed picture of where improvements are being made and where they aren't.

One of the areas that doesn't seem to scrape a pass mark is fresh water quality.

The report says the quality of water in rivers, streams and lakes across the country is variable and depends on what the land in the catchment area is used for.

Water quality is "very good" in areas with indigenous vegetation and less intensive use of land, but it's poorer where there are pressures from urban and agricultural land use.

"Rivers in these areas have reduced water clarity and aquatic insect life, and higher levels of nutrients and Escherichia coli (E.coli) bacteria," the report says.

High nutrient levels can result in nuisance slime and algae growth, which can impact on river flows, block irrigation and water supply intakes, and smother riverbed habitats.

It can also affect recreational activities, like swimming.

There has also been a 12 percent increase in the total amount of nitrogen leaching into rivers from soil, but the increase from agriculture has been even greater.

The blame for that has been pinned on increasing dairy cattle numbers and nitrogen fertiliser use.

Dr Smith says the degradation of fresh water quality, which has been going on for a couple of decades, needs to be addressed.

He told reporters the dairy industry is working on what it can do to reduce its impact on water quality.

But he said some of the worst examples of water quality are actually found in urban streams and rivers.

"This issue around fresh water is not one of town versus country, but both town and country are going to have to lift their game."

The report also highlights critical concerns about land erosion and soil compaction, which can also impact water quality.

There have, however, been some improvements.

There's been a drop in airborne particles – which can cause respiratory and cardiovascular problems – and an almost 50 percent decrease in carbon monoxide emissions from transport.

The report, the first of its kind, took two years to produce and used data from councils and government agencies like Niwa and the New Zealand Transport Agency.