Waterways in 80 per cent of New Zealand’s monitored catchments are showing improvement, or stability in water quality, which is at odds with the usual rhetoric, says Dr Paul Le Miere.

Paul, who is Federated Farmers North Island regional policy manager, says statistically validated measurements of water quality from 2004 to 2013 shows promising trends. And in many cases those results are due to farmers making changes in managements, including effluent and the fencing off waterways.

“Everything is not going backwards as you might assume from the rhetoric.”

Paul says the 10-year trend study shows insect life in 87 per cent of monitored waterways is improving or not changing. E-coli in 86 per cent of waterways is improving. The work of farmers’ in effluent management and urban communities with sewerage systems are making significant difference, says Paul.

“Phosphorus is a massive good news story with significance improvement in total phosphorus levels in 94 per cent of waterways, which equates to 10 times more improving than declining – and that’s thanks to the work of dairy and drystock farmers around sediment control, phosphorus use and riparian plantings.

“Nitrogen improvement, at 64 per cent, is not as high in terms of improving; but it’s not going to hell in a hand basket.”

Paul says there is a lag time with nitrogen leaching into ground water and that varies from catchment to catchment.

Hot spots

Federated Farmers is not denying there are problems with water quality, but Paul says most are in “hot spots”, some including sites of former meat works, fertiliser plants or sewerage systems – and these need to be targeted.

“We need to work on those hot spots rather than say everything is going to rack and ruin. We need to understand what is working in catchments, what is making a difference and not assume all are going backwards.”

Federated Farmers supports the National Policy Statement on fresh water and what it is setting out to achieve but has concerns about the scientific knowledge around many of the processes and how some regions are approaching the requirements.

The NPS and other water processes need to focus on the objectives and keep in mind what they are trying to achieve. And the most cost-effective ways of getting there and under appropriate time periods, giving regard to legacy issues must also be considered, says Paul.

“Current understanding of water science is poor including how things happen and from all sources, including urban and hydro power generation. Much is very theoretical and we need to understand better in order to make decent decisions we can live with.”

Science skinny

Enforcing nitrate caps will achieve nothing apart from restricting farmers. “The science is skinny and theoretical. We don’t know the attenuation of nitrogen or when it falls out of the root zone. We don’t know what happens in different soils – our knowledge around that is superficial.”

Overseer, the management tool used to measure leaching, is also inconsistent, says Paul. “Between different versions the difference in N leaching is significant, as much as 100kg of nitrate on some farms which is a fundamental problem.”

Paul says Federated Farmers is also concerned about increasing talk, including by politicians, of resource rentals which could see water users taxed.

It could also mean water use rights are traded to the highest value land use, the theory being this would generate economic growth. Paul believes this would be inefficient and would just monetarise contaminates with some farmers getting windfalls and some not.

Dr Paul Le Miere was among the speakers at the 70th Annual Provincial Conference and AGM for Bay of Plenty Federated Farmers.