Freshwater: what’s the deal in Canterbury?

What’s going on with farming and freshwater in Canterbury? Is it as bad as some people claim? Is water quality, in the form of nitrate pollution, getting better or worse? And is enough being done about it?

Steve LowndesLet’s start by acknowledging what we know: we have some big environmental issues in Canterbury. We know freshwater quality has declined, particularly in the past 25 years or so. We know biodiversity has taken a hit and we have cleared land and put native species at risk right across the region. We know we must also adapt to the effects of climate change, which are already starting to be felt. We need to address these environmental issues, while at the same time ensuring we have thriving communities and a sound and sustainable economy.

It’s worth remembering at this point that the quality of the water in our waterways is not just a rural issue. The two most polluted rivers in Canterbury are in Christchurch because of the intense effects of urbanisation.

It’s also easy to put a rose tint on the past, but the way we used to do things wouldn’t be acceptable today. Just think of the now outlawed practices of discharging untreated effluent from sewage works, freezing works and other industry directly into streams and rivers. And it wasn’t that long ago we stopped discharging treated effluent directly into the Ihutai Avon/Heathcote Estuary.

Back to today. Let’s start with nitrate pollution*. Nitrate levels in our waterways have been rising and it is mostly caused by more intensive farming over the past 20 years and more.

Some people have said the solution is to ban or drastically reduce numbers of dairy cows. A hypothetical analogy would be to ban trucks from the road to fix the issue of trucks causing a higher road toll. This would probably solve the immediate problem, but it would cause widespread social and economic issues, some foreseeable and others that might surprise us.

If cows were banned in Canterbury, there would be a reduction in nitrate pollution. But it would also cause very significant social and economic problems, as well as unintended environmental issues as a result of farmers no longer being able to afford to maintain their land. We believe there are more acceptable and sustainable ways to achieve a long-term reduction in nitrate pollution.

In the trucking example instead of banning trucks we could make roads safer by enforcing stricter rules (speed limits, load limits, restrictions on driving hours), by improving the trucks (better brakes, suspension systems, GPS and other technology) as well as ensuring better drivers (safety training, incentives to drive safely, and on-board camera systems).

We’ve taken a similar approach to dealing with nitrate pollution. And by ‘we’ I mean Environment Canterbury but also farmers and the agri-sector as a whole. Our response is comprehensive and includes social, cultural and economic values, as well as the need to protect and improve the environment. As in the trucking analogy, we now have tighter rules and stricter compliance, better technology and improved systems, as well as more training of land managers/farmers. A key additional tool is the work with agri-industry groups to implement on-farm behaviour change.

Our nitrate pollution rules, introduced in 2012 via the Canterbury Land and Water Regional Plan, are among the strictest in the country. Since then even more stringent rules have been introduced in collaboration with the community in areas with rising nitrate levels (Selwyn district, Ashburton Hinds, and the South Coastal Canterbury area).

Land users are now required to measure and manage nitrate leaching via a consent to farm. They are also required to have a Farm Environment Plan and their performance against this plan is graded by independent auditors. We work with those who receive an A or B grade (acceptable) to maintain and improve their performance. We work more closely with those who receive a C or D grade (not-acceptable), which includes scheduling more frequent compliance visits and audits.

There is also some confusion and controversy around the acceptable level of nitrates in fresh water. Some people are calling for a nitrate level of 0.8mg/L in rivers rather than the level of 6.8mg/L set as a national bottom line in the National Policy Statement for Fresh Water. The first number – 0.8 – is not based around any reputable science. We do know that higher nitrate levels affect fish and invertebrates in fresh water, but there is no scientific reason to pick 0.8mg/L for a nitrate limit.

The second number – 6.8 – is the national bottom line for nitrate level set in the National Policy Statement for Fresh Water. It’s important to understand this number is not a limit (or target) for nitrate pollution across Canterbury. In many areas – particularly high-country streams and alpine lakes – nitrate levels are naturally very low (below 1mg/L) and we are working to keep them that way. The only areas where 6.8mg/L is used as a guide is in areas where nitrate levels are already elevated, and we are working to get levels down to the NPS bottom line.

Our responsibility, under law, is to ensure that water quality is maintained or improved. In the case of nitrate pollution this can translate into ensuring nitrate levels are maintained or reduced. We are not allowed to sit back and let nitrate levels rise – even when they are very low and well below the 6.8mg/L guide we must continue to act to protect the environment.

It is interesting to see from the latest analysis that we are seeing improvements in water quality over the past 10 years. This is because of the comprehensive approach we and the farming industry have taken to addressing environmental concerns. This includes stricter and more targeted planning rules, more planting and fencing of streams, better effluent management, improved irrigation practices, millions spent on biodiversity restoration projects, smarter technology and investment in on-farm systems, better on-farm training, improved compliance and monitoring, as well as the programme of industry-agreed Good Management Practices and the introduction of audited Farm Environmental Plans for most farmers in Canterbury. The improvements we’re seeing are heartening for all of this effort but we know we need to keep on with the work to see sustained improvement to a water quality that we can all be satisfied with.

In short, yes there are definitely still issues. But it is not wide-spread doom and gloom by any means. The issues are understood by scientists, the rural community, industry and decision makers, and as a result a range of actions are happening on the ground to good effect. A lot is being done in Canterbury that the region can be proud of as we are, in many ways, leading New Zealand by example.

*Nitrate pollution occurs due to nitrate, predominantly from urine, seeping through the soil and into waterways. It is sometimes referred to as ‘nutrient loss’ or ‘leaching’.