Top scientist: Fixing freshwater issues an 'enormous challenge'
A report by New Zealand's top scientist has urged politicians to address freshwater issues, which he says are clearly linked to intensive farming and urbanisation.
Professor Sir Peter Gluckman, chief science advisor to the prime minister, has released a report analysing the health of New Zealand's freshwater based on existing science and data.
It found clear evidence the freshwater estate was under pressure in terms of both water quality and quantity. There was a link between farming and declining water quality in pastoral areas, and contamination of urban waterways by expanding cities.
Fixing the problems would require bold decision making and possibly a rethink of our economic strategy, with a quick fix being "scientifically impossible".
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"The science is clear – New Zealand's fresh waters are under stress because of what we do in and around them," the report said.
"Major changes will be needed in some sectors of the economy, and in planning and consent activity. These changes will be neither instantaneous nor cost-free."
Work on the report began nearly a year ago and its release was accelerated after the Government's recent freshwater announcement.
It followed an OECD report last month that said New Zealand was showing its environmental limits and starting to make environmental trade-offs.
The OECD said a more sustainable economic strategy was needed if New Zealand was to remain competitive.
Prime Minister Bill English largely dismissed the OECD report's recommendations and said the issues were already being addressed.
Political opponents and environmental lobby groups disagreed.
The state of freshwater had been compromised by human activity over many decades, Gluckman's report said.
There were a long list of contributing factors, but the major drivers of concern were rural land use practices, power generation, and urban development.
It said the greatest threat overall was diffuse pollution – a type of pollution that cannot be traced to a single, direct source – in both rural and urban areas.
"Diffuse source pollution is widespread, and national and international experience shows that it can be difficult to manage."
In cities, the greatest source of diffuse pollution was stormwater runoff, which had high concentrations of heavy metals such as zinc.
In Auckland and Christchurch, wetlands and swamps had been drained and streams polluted. Christchurch's Avon and Heathcote rivers were prime examples, polluted with heavy metals and rarely meeting contact recreation standards.
Recent dairy intensification had led to obvious water quality impacts, the report said, and made a "disproportionately large contribution" to the diffuse nitrate pollution in waterways.
The presence of E.coli in rivers, typically associated with swimmability, was also most commonly seen in pastoral areas.
"Although urban diffuse sources are important at the local scale, by far the most important source of faecal contamination nationally is input from pastoral farmland," the report said.
"Strong positive correlations have been reported linking E.coli concentrations in rivers to the proportion of upstream catchment used for intensive agriculture.
"The link between pastoral intensification and declining water quality is clear and has been acknowledged by recent Government reforms of water legislation that seek to limit contaminant discharges to fresh water."
The "very rapid intensification" of farming in recent years presented "enormous challenges", the report said.
While recent data showed phosphorous and ammonia concentrations were improving in both pastoral and urban areas, nitrate levels were becoming worse.
New ways of using the land for economic gain needed to be found to meet New Zealanders' vision for freshwater, the report concluded.
It would lead to a "core policy dilemma" – can land continue to be intensified to meet economic goals while managing environmental effects, or would the drive for agricultural intensification need to be reviewed?
"This is a major and complex set of decisions for New Zealand which merits deep discussion beyond traditional political rhetoric.
"New ways of utilising our land for economic gain that also have lower environmental footprints need to be found and adopted if we are to meet the vision New Zealanders have for their fresh waters."
The report was produced with input from staff at Niwa, the Ministry for the Environment, the Department of Conservation and numerous academics. It was externally peer reviewed.
The Ministry for the Environment and Statistics NZ are releasing a report on the state of freshwater later this month.