River condition

The data in this indicator is no longer being updated.

Stats NZ is developing well-being indicators, Indicators Aotearoa New Zealand - Ngā Tūtohu Aotearoa, to track New Zealand’s progress. As the well-being indicators have similar aims to the NZ Progress Indicators and NZ Social Indicators, we are reviewing the future of these existing indicators.

Please contact us at info@stats.govt.nz if you have any questions.

 

Neutral change

The condition of our rivers is mixed, with some parameters improving or stable while others are deteriorating

  • Image, river quality
    • Phosphorous concentrations improved at 40 percent of river monitoring sites while bacteria concentrations showed no evidence of a trend at most monitored sites.
    • Nitrate concentrations and macroinvertebrate condition (aquatic insect life) deteriorated at more sites than improved. High concentrations of nitrate can cause excessive aquatic plant growth and are toxic to fish. The composition of macroinvertebrate communities reflects changes in water quality, river habitat, and catchment condition.

     

    1. Trends were calculated using data collected from 1999 to 2012. An improving or deteriorating trend is one that is statistically significant and ecologically meaningful. Improving means the trend is towards a more natural state, while a deteriorating trend is towards a more modified state.
    Note
     This graph is interactive. Hover over the data points to see the exact values. Click legend text to hide or show variables.

    View source data

    The source data for this indicator is available from Environmental indicator for fresh water: River condition on the Ministry for the Environment website.

    Definition and measure

    Freshwater is one of New Zealand’s most valuable natural assets and is important for our social, cultural, and economic well-being. The river condition indicator describes the trend of New Zealand’s rivers and streams in terms of their biophysical environmental condition. It does not include other sources of freshwater.

    This indicator measures three aspects of river condition: 

    • nutrient concentrations (dissolved reactive phosphorous, nitrate)
    • bacteria (E.coli)
    • the presence of aquatic insects (macroinvertebrate community index).

    High nutrient concentrations can have a detrimental impact on river ecology and recreational values. Bacteria are an indicator of pathogens associated with the faecal contamination of water bodies. The presence of aquatic insects shows the diversity and resilience of freshwater ecosystems.

    Regional councils and the National Institute of Water and Atmospheric Research collect data at over 300 sites across the country. Using data for a 10-year period ensures that any detected trend is more likely a result of a genuine pattern, rather than from short-term events like heavy rainfall. Trend analysis groups the sites into those that are improving, deteriorating or show no evidence of a trend.

    Technical changes since 2010

    The river condition indicator replaces the nitrogen in rivers indicator used in Key findings on New Zealand's progress using a sustainable development approach: 2010.

    Previous publications

    Key findings on New Zealand's progress using a sustainable development approach: 2010
    Measuring New Zealand's progress using a sustainable development approach: 2008
    Key findings on New Zealand's progress using a sustainable development approach: 2008

    Page updated December 2014

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