One expert says a new report on New Zealand's declining freshwater quality is a "sobering snapshot" of how the country's "economic and physical well-being" is being harmed without additional Government action.
The report, jointly authored by the Environment Ministry and Stats NZ, collates and outlines the latest data and research about the country's water bodies.
Otago University environmental health researcher Tim Chambers said it was a "sobering snapshot" of the state of New Zealand's freshwater ecosystems.
He said the report "clearly showed" that further action is "required to protect our freshwater for our physical and economic well-being".
"An estimated 45% of our river length is not suitable for swimming due to bacterial contamination. In 2017, 1200 people got sick after reporting contact with recreational water."
Chambers said bacterial contamination at tested sites was either getting worse or not getting better.
"The national groundwater monitoring programme shows that 68% and 19% would fail the drinking water standards for bacterial and nitrate contamination, respectively.
"For bacterial contamination, 82% of all sites are either getting worse (50%) or showing no improvement (32%).
"For nitrate, 51% are either getting worse (35%) or not improving (16%) from a 2009 baseline."
Environment Minister David Parker said that making "substantial improvements to water quality is an intergenerational challenge that requires a determined and sustained effort."
"To have nearly half of New Zealand's rivers classified as 'unswimmable' is an indictment on our country. It is something that I and most New Zealanders are not prepared to accept," he said.
"Because of the time lags in the data, today's report essentially shows the starting position for our 2020 freshwater reforms.
"The Government said the reforms will take a generation to reverse the damage done to our waterways in the past decades, but we expect to see material change within five years."
The ministry's Natasha Lewis said ecosystems and water quality was improving in some places but worsening in others.
"Many lakes, rivers and other water bodies are under pressure, mostly due to the way we’re using land and water, and from the changing climate," she said in a media release.
"While the report doesn't specifically look at recent events such as Cyclone Gabrielle that have severely affected communities and caught the country's attention, it does help make sense of what's happening more broadly."
The report notes that Aotearoa has experienced one of the world's highest rates of agricultural land intensification over recent decades.
According to the report, modelling shows the efforts by farmers to reduce fertiliser use and keep stock out of waterways helped to reduce the amount of phosphorus and sediment reaching rivers between 1995 and 2015.
However, because the number of farms grew, it's estimated the total amount of nitrogen reaching rivers still increased in that time.
"Dairy cow numbers have increased nationally from 3.4 million in 1990 to 6.3 million in 2019, with Canterbury and Southland seeing ten-fold and sixteen-fold increases during this same period, respectively," Chambers said.
"Irrigated land has doubled during a similar period, with around 75% of this increase attributable to dairy intensification."
Some of the other key findings identified by the report included:
- 36% of lake monitoring sites improved, while 45% worsened between 2011 and 2020, based on a nutrient and algae-level measure of ecosystem health.
- It’s estimated 45% of New Zealand’s total river length is not suitable for activities like swimming, according to campylobacter infection risk models from 2016 to 2020.
- About two-thirds of freshwater native bird species were either threatened with extinction or at risk of becoming threatened in 2021.
The Otago University researcher said the report highlighted research gaps, including national monitoring and reporting, research into the health impacts of key contaminants and mātauranga Māori.
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