environment

NZ’s freshwater at risk, report shows

A new report from the Ministry for the Environment shows the scale of the threat to New Zealand's freshwater resources, Marc Daalder reports

The latest triennial report on the state of New Zealand's freshwater resources paints a dire picture of an environment under threat of destruction.

Freshwater environments in all non-natural areas, including urban, forestry and farming environments, are heavily polluted, the report found.

The Ministry for the Environment (MfE) and Statistics NZ report, Our Freshwater 2020, examines new data through the lens of four "priority issues": the threat to wildlife and ecosystems, the pollution of freshwater, the effects of changing water flows on rivers and lakes and the impact of climate change.

Many changes to freshwater environments, the report found, "are slow to reverse, and some are irreversible. Loss of species and ecosystems could have significant impacts on our identity, wellbeing, cultural values, and economy."

Together, the four issues depict an environment in sore need of attention and resourcing, Forest & Bird freshwater advocate Tom Kay said.

"New Zealand's freshwater has reached breaking point. Political and policy leaders have a once-in-a-lifetime opportunity to make the changes we need to save our people and our natural world. We need clean water and flowing rivers, and right now our fresh water needs us to protect it," he said.

The report comes a month after Newsroom reported that polluted waterways in the Hauraki Plains had led to the deaths of thousands of native eels, ducks and other wildlife.

Species and ecosystems at risk

The headline statistic on native species is gloomy: 76 percent of native freshwater fish are now threatened by or at risk of extinction. Since the last report in 2017, one species has officially been labelled extinct, although it was last sighted in the 1940s.

Several of the threatened species are taonga, including longfin eel (tuna), four species of whitebait (shortjaw kōkopu, giant kōkopu, kōaro, and īnanga) and lamprey.

A quarter of freshwater invertebrates are similarly threatened by or at risk of extinction, as well as a third of freshwater plants and two thirds of native birds that rely on freshwater environments for feeding or breeding.

The habitats themselves are also suffering. Since humans first settled Aotearoa, 90 percent of the country's wetlands have been drained. In the 15 years to 2016, more than 200 wetlands totalling 1247 hectares were lost nationwide. Between 1990 and 2012, 157 hectares were lost in Southland alone.

About 18 percent of rivers assessed over the past two decades had a low "index of biotic integrity" - in other words, lower than expected numbers of freshwater fish. These scores indicate a degraded native fish community and were mostly found in Southland, Otago and the central North Island.

This chart from the MfE report shows the results of assessments of freshwater fish life at nearly 6,000 sites across New Zealand by NIWA. A score of under 20 indicates a degraded environment for fish.

Another measure of biodiversity and ecosystem health, the macroinvertebrate community index (MCI), found that more than 75 percent of New Zealand's total river length had good or excellent scores. However, in nearly 40 percent of these cases, the trend was worsening, while it was only improving in about a quarter. The remainder, 37 percent, had an indeterminate trend.

Rivers are not alone in struggling. In a small sample of lakes where data on submerged plant life was available, 36 percent were in poor condition or had no plants, 32 percent were in moderate condition and 34 percent were in excellent condition. The vast majority - 88 percent - had invasive plant species.

Nearly half of the 3,800 lakes larger than 1 hectare had poor or very poor water quality, as indicated by high nutrient levels, murky water and a propensity for algae blooms. Just 15 percent had good or very good water quality while the remaining 38 percent were of average quality.

The report found that human alteration of the landscape, in-stream structures like dams, fishing, loss of habitat and the presence of invasive species have all contributed to the threat to native wildlife and habitats.

Water pollution remains a problem

The low water quality in many lakes is indicative of the report's second priority issue: pollution of freshwater environments.

The vast majority of rivers in urban, farming and forestry areas are polluted, according to the report.

In urban areas, 99 percent of the total river length exceeds one or more of the guidelines for nutrient or turbidity (cloudiness) levels. Nearly half of the river length exceeded expected E. coli levels.

In pastoral areas, the situation is slightly less dire. Although nutrient or turbidity levels were exceeded in 95 percent of the total river length in these areas and E. coli levels exceeded in 24 percent, the degree to which these guidelines were breached was lower. The median levels for turbidity, for example, where 57 percent higher in urban areas than pastoral ones and E. coli levels in urban areas were double those in farm rivers.

Nonetheless, the impact of agriculture may be greater because of the sector's use of larger areas of land. While just 1 percent of the country's total river length was counted as urban, more than half is pastoral. Moreover, the study states, "studies at national, regional, and catchment scales show that the concentrations of nitrogen, phosphorus, sediment, and E. coli in rivers all increase as the area of farmland upstream increases".

Forestry areas, which cover just six percent of New Zealand's river length, exceed nutrient guidelines in 95 percent of cases and turbidity guidelines in 27 percent of cases.

Rivers in native forest catchments, meanwhile, have fared better. Less than 60 percent of river length in native forest areas exceeded nutrient guidelines, less than 10 percent exceeded turbidity guidelines and less than 5 percent exceeded E. coli expected levels.

The prevalence of such pollutants in waterways also threatens human health. "In 2017, there were 427 notifiable illness cases of campylobacteriosis, 250 of giardiasis, 219 of cryptosporidiosis, 135 of salmonellosis, and 88 of E. coli infection for cases where people reported contact with recreational water," the report stated.

Rivers aren't the only ones struggling with pollution, however. In addition to the water quality issues noted above, nitrogen concentrations in 28 percent of lakes with upstream catchments in farming areas exceed the recommended levels. Such lakes make up 47 percent of the 3800 lakes of one or more hectares in the country.

This figure rises to 44 percent for lakes with upstream catchments in urban areas - which make up about 2 percent of the country's lakes. For lakes with upstream catchments in forests, 8 and 19 percent have nitrogen concentrations exceeding recommended levels, for native and exotic forests, respectively.

According to the study, "77, 70, and 67 percent of lakes with upstream catchments in the urban, pastoral, and exotic forest land-cover classes respectively are in poor or very poor ecological health, due to frequent algal blooms and murky water caused by high nutrient concentrations". This figure drops to just 19 percent for lakes with upstream catchments in native forests.

The report found that wastewater and stormwater discharge into rivers, the clearing and converting of land, felling and replanting of forests, change from sheep to cattle farming, intensification of farming and the use of pesticides are all to blame for the degradation of freshwater environments.

Redirection of water flows examined

Besides an increase in water pollution, farming intensification has also been blamed for the third priority issue in the paper: the redirection of water flows.

Irrigated land has doubled over the past 15 years and irrigation makes up the second-most consented allocation of freshwater. When looked at in terms of the maximum allowable rate of water use, 45 percent of consented allocation goes to hydroelectricity and 37 percent to irrigation. By volume of consumption, however, irrigation takes the lead at 58 percent, because hydroelectricity plants don't consume the water they use.

"Irrigation schemes change the natural flow of a river. Thousands of kilometres of water races have been built
to supply water for irrigation, stock watering, mining, and other purposes," the report states. Hydroelectric plants can also divert the course of rivers or reduce their flow.

Other water redirection is also cause for concern. About 10 percent of the country's landmass has been artificially drained, largely to make room for agricultural expansion.

The report lays blame for these issues at the feet of increased demand for irrigation and residential and industrial water use and lower rainfall nationally. Water bottling has not played a major role in this, the report states, noting that just 162.9 million litres of water were bottled last year, or 0.0012 percent of the water consented to be taken for consumption. The vast majority of this was for the domestic market.

The impact of climate change

The final priority issue was the impact of climate change on freshwater. Although data on this issue is still sparse, there is a handful available that the report highlights.

Rainfall numbers don't seem to have been significantly affected by climate change so far. Of 30 areas, four (Auckland, New Plymouth, Rotorua and Taupō) have seen decreased rainfall between 1960 and 2016, while Napier and Timaru have seen an increase.

Several floods, including in Golden Bay in 2011 and Northland in 2014, have been identified has being affected by climate change.

Since over the past century, the average temperature in New Zealand has risen by 1 degree.

At a quarter of monitored sites, soil has become drier in ways consistent with a warming climate.

Between 1977 and 2016, glaciers have lost nearly a quarter of their ice - about 13 cubic kilometres. From the peak in 1997, glaciers lost 15.5 cubic kilometres of ice, or enough to fill Wellington Harbour 12 times over.

Sea level rise, although minor, has picked up pace in recent years. The average rate of rise over the past 58 years was double that in the prior 60 years, and seas have risen by 1.81 millimetres each year since records began.

Computer modelling can help make up for some of the gaps in the data. According to projections, river levels are likely to rise on the west coast of the South Island and on the eastern side of the Southern Alps, but may ebb elsewhere, particularly the Waikato and Northland.

Snowfall could also decrease by between three and 44 percent by 2040. Decreases in alpine snowfall could weaken streams and rivers that are used to power hydroelectric stations, the report states.

"Extreme rainfall, drought, and sea- level rise may have cumulative effects that intensify the pressures of our activities on freshwater."

On this final priority issue, there is only one cause: the rise in greenhouse gas emissions globally. New Zealand is not immune from this phenomenon. Between 1990 and 2017, net emissions jumped by 57 percent.

Reactions to report

Environment Minister David Parker, who is pioneering a freshwater policy that straddles the middle ground between the desires of environmental activists for a crackdown on polluting activity and the wishes of farmers to keep on dairying with no restrictions, welcomed the new report.

"New Zealanders want to swim, fish, gather mahinga kai and enjoy freshwater as our parents and grandparents did. We also need clean water to drink and irrigation to support a sustainable economy," he said.

"But our water is suffering as a result of human activities, including the effects of climate change."

Climate Change Minister James Shaw also highlighted the report's conclusions on climate change's impact on the environment.

"Freshwater is crucial to all of us – not just for drinking, but for farming, industry and energy too. The freshwater report shows clearly the pressures we are putting on this precious resource as a direct result of climate change. Action on climate change is not only something that will help our economy and improve our communities, but it will improve the quality of our freshwater too," he said.

Meanwhile, Conservation Minister Eugenie Sage said the report showed the need for increased biodiversity efforts.

"The freshwater report outlines well the pressures on native fish such as īnanga/whitebait and the importance of reducing sediment and nitrogen pollution and barriers to fish migration to ensure healthy fish populations," she said.

"I’m proud of the work done last year to strengthen legal protection for native freshwater fish and DoC’s efforts now on specific measures to look after whitebait in streams and rivers around Aotearoa. The Biodiversity Strategy is currently being finalised after public consultation. It will commit New Zealand to a clear vision and specific measures to better protect our unique freshwater habitats and plants and wildlife."

Not everyone is happy with the work done so far, however.

Federated Farmers focused on how pollution is present in urban and forestry environments, in addition to farming areas. However, they ignored the fact that pastoral areas contain more than seven times as much river length than urban and forestry areas combined.

"Those catchment-specific issues bring people together and farmers in all of our regions are mixing in with environmentalists and wider community groups to make improvements that tackle local problem areas and priorities. Blanket rules are expensive and often ineffective," Federated Farmers environment spokesperson Chris Allen said in a statement.

The organisation also highlighted the need for better water storage in drier areas and as dry years become more common.

Forest and Bird, meanwhile, said the report displayed the need for urgent action.

The group "is urging local and central Government to heed the warnings in this report. The path we are on threatens our native species and our own wellbeing," Kay said.

"New Zealanders love nature and want to protect it. Right now, we have an opportunity to transition away from environmentally destructive farming, forestry, and urban development practices. The right legal reforms, economic incentives, and regulatory systems can protect and restore our fresh water."

"This report makes clear that New Zealand urgently needs a major transition away from old models of business, because they are harming us, and they are harming the environment."

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