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  Community » Waikato Progress Indicators - Tupuranga Waikato » Report cards » River water quality

River water quality

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RIVER WATER QUALITYimage

no significant change    NO SIGNIFICANT CHANGE

 

The average proportion of unsatisfactory river water samples for ecological water quality for the period 2011-2015 at over 100 monitoring sites throughout the Waikato region was largely unchanged from 2003-2007.

This indicator is the percentage of unsatisfactory river water samples for ecological water quality in the Waikato region’s rivers and streams, as an average across all sites measured.

Why is this indicator important?

Monitoring a representative cross-section of rivers and streams across the Waikato region helps councils to assess the suitability of their water quality for native water plants and animals to live in (ecological water quality). Water quality not only affects the surrounding habitat; it can also impact elsewhere, because what happens in one area of the catchment can directly affect what happens in another. For example, soil erosion issues in the Waipa catchment can contribute to sedimentation in the Waikato River and flooding in the Lower Waikato. Contamination at one site in a river can flow to other sites further down the catchment.

Monitoring these sites helps councils to identify and manage issues so they can protect or improve water quality in these areas. Land use and what people do are two key areas influencing water quality. Sharing this information with people in the region can encourage them to consider the impact of their activities on water quality. They may also become motivated to work together with councils and other people in their community to keep the Waikato region’s water quality and its environment protected now and in the future.

Percent of unsatisfactory river water samples for ecological quality

PeriodPercent unsatisfactory
2003-2007 29
2004-2008 29
2008-2012 29
2009-2013 29
2010-2014 28
2011-2015 28

 

Water quality trends in the Waikato River between 1995 and 2015 (based on methods from Waikato Regional Council's Technical Report 2013/20(external link).)

Chart showing trends in river water quality  

What is this indicator telling us? 

  • River water quality for ecological health is generally good across the region. However in areas where land use is more intensive, water quality for ecological health is poorer (for example, Hauraki and the lowland tributaries of the Waikato River). This is mainly because of the greater intensity of land use in the lowland parts of the Waikato region.
  • Over the past 25 years, water quality at the 10 Waikato River sites has been mostly stable, with some notable improving trends (total phosphorus, chlorophyll a, arsenic) as well as worsening trends (nitrate, biochemical oxygen demand). There have been a relatively small number of improvements in water quality, particularly the improvement in concentrations of total phosphorus at 8 of the 10 sites. Levels of total nitrogen increased at several sites along the Waikato river, probably as a result of land use changes over recent decades. The overall rate of increase over the past 25 years was about one per cent per year. Pressures from wastewaters have generally decreased over recent years, but agricultural land use has continued to intensify.

Check out related information on our website and other organisations’ websites listed on our Waikato Progress Indicators’ Useful Links page.

Click here to view report cards

 


DATA SOURCE AND SUPPORTING INFORMATION

The Waikato Regional Council monitors more than 100 specific sampling water quality sites across the region. Council’s monitoring describes the average 'pass rate' for seven water quality measures: dissolved oxygen, pH; turbidity, ammonia, temperature, nitrogen and phosphorus. Water quality trends(external link) in the Waikato River between 2004 and 2015 use methods detailed in Waikato Regional Council Technical Report 2013/20(external link)

Water quality data are reported online by Waikato Regional Council annually on the basis of five-year rolling average figures showing percentage of samples meeting guidelines for excellent, satisfactory or unsatisfactory river water quality across various groupings of monitoring sites (e.g. Lower Waikato River). For a variety of reasons it is not prudent to use annual comparisons of five-yearly rolling data (as in the previous MARCO method). Instead it was agreed to use the five-year rolling average percentage of unsatisfactory samples (all sites) compared with a 2003-2007 baseline period.

Update details: Latest five-year rolling average (2011-2015) compared to baseline (2003-2007).

Customised data request requirements: Contact is Waikato Regional Council for the latest five-year rolling average percentage of unsatisfactory river water samples for ecological water quality in Waikato region rivers and streams (all sites average).

DATA AVAILABILITY – OTHER THAN WAIKATO REGION:

Territorial Authority (TA) disaggregation: No

Other regions: No

New Zealand: No

Other countries/ Organisation for Economic Co-operation and Development (OECD):  No

 

 

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