Will we accept firm water quality limits in our
agriculture, Dugald MacTavish asks.
Farmers say water quality limits could threaten farm
viability. Photo ODT files.
Our New Zealand farmers have been enormously resourceful
and highly successful at evolving the clever and productive
farming systems that form a cornerstone of our economy.
This has not been without its costs, however, and
state-of-the-environment reporting has cast a harsh spotlight
on its effects on our waterways; most notably in
sub-catchments with intensive dairying.
A Niwa study of about 300 lowland waterways in New Zealand
showed that 96% in pastoral catchments, and 100% in urban
catchments, failed the pathogen standard for contact
More than 80% of the sites in pasture catchments exceeded
guideline levels for phosphorous and nitrogen. More than 60%
of our native freshwater fish are now listed as threatened
In response to this, the National Policy on Freshwater
Management requires all regional councils to set firm limits
on the take and discharge of contaminants to stem
deterioration of water quality in our rivers.
Otago Regional Council commissioners hearing submissions on
the ORC's recent proposal to set water quality limits for
discharge to land and water have faced an avalanche of
farmers and their experts arguing these represent a genuine
threat to farm viability.
Similarly, farming interests in the Manawatu are appealing
the Environment Court's decision in favour of a plan to set
water quality limits to improve the Manawatu River.
In response, the Government has shown the old attitude that
environmental consideration is OK just so long as it doesn't
get in the way of the economy, is still alive and well.
Commenting after the Environment Court decision, Primary
Industries Minister David Carter indicated it would be
unacceptable for regional councils to set nutrient load
limits that constrained farm profitability, and that the RMA
might need review to ensure more thorough economic-impact
assessment of such proposals.
Yet other evidence at that same hearing cited specific
examples of farmers' successfully reducing their nutrient
footprint by a third or more with relatively straightforward
management changes, sometimes even improving profitability.
So is it wise simply to legislate farming around this one in
the same way we have for greenhouse-gas emissions?
In 2009, a group of international scientists identified nine
"planetary boundaries" or biophysical thresholds beyond which
the cumulative impact on the planet exceeds its carrying
capacity and becomes unsustainable. These included global
freshwater use, the phosphorus cycle flow and the nitrogen
They concluded the last two have already exceeded safe
boundaries, reactive nitrogen hugely, and that nitrogen flow
into the earth system must be reduced by 75% at a global
Even with best practice, containing nitrogen leaching under
intensive outdoor farming is very difficult, and in
combination with phosphorus is the primary cause of
eutrophication and algal growth and, in some cases, toxicity
in our freshwater systems.
Together, they may also cause similar undesired non-linear
change in terrestrial and marine systems, indirectly
aggravating climate change.
The same scientists found a risk of global phosphorus
scarcity in coming decades. So more efficient use and
retention of phosphorus within agricultural ecosystems would
reduce both pollution and farm vulnerability to shortage.
It is clear that in New Zealand we have reached a land-use
Best science is telling us that, for the safety of our local
and global environments (and, indeed, for the integrity of
our pure marketing brand), we need to operate our land use
and other systems within ecosystem limits.
Adhering to those limits will inevitably have economic
implications for some businesses and communities.
But if compliance is not possible, wouldn't that indicate the
high nutrient and water (not to mention high energy,
emissions, capital and often debt-laden) industrialised farm
model in which the Government holds such hope has proven a
potential liability in an increasingly resource-constrained
I'm sure all water users would feel better knowing they were
returning free, publicly owned water fit for others to enjoy.
So while there may be some pain, surely the sooner we accept
critical limits, the sooner we can again start to develop
world-leading but more sustainable and robust farming
systems. Indeed, if the planetary implications of failing to
do so are real, do we have any choice?
- Dugald MacTavish is a water resources
consultant based at Moeraki.