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Nelson region

River Quality

Nelson City Council operates a network of 28 river ecology monitoring sites including many on small streams within the urban area. Sites are monitored four times a year for a range of tests with biological monitoring undertaken once a year in early summer.

The water quality classification is derived from a combination of water quality parameters and biological indicators. The ‘long term’ classification, from information collected between 2000-2007, is compared against the annual result for each site to track changes in water quality over time.

In addition, Nelson City Council monitors a network of small streams for flow and water temperature, mainly for assessing water resources outlined in the Nelson Regional Management Plan (Freshwater Plan).

Council staff have initiated a number of studies and assist communities, schools and groups to improve and maintain our waterways. For further information about Council environmental monitoring please visit Nelson City Council's website.

Nelson Rivers and streams are affected mainly by sediment resulting from land disturbance, microbial contamination associated with livestock and feral animals, and from urban stormwater in the city area.

Overall water quality is highest in the forest catchments that dominate most of the Nelson land area. It is less satisfactory in intensively farmed valley bottoms and poorest in urban streams receiving road, commercial and industrial stormwater runoff.

Catchments 10 Scientific Indicators
Scientific data for this region

This dashboard shows information on the data collected by the regional councils for water quality indicators, analysed as state and trend.

The state for the region is represented by the median concentration for the parameter across all sites within the region and then compares that value to the quartiles for all monitored sites in New Zealand.

Click on the parameters state icons to compare this region with others nationally.

  • State

    State shows how the median of samples from this site compares to other sites

  • Trend

    Trend shows how the quality of water is changing over time. Depending on the sampling history duration, five and ten year timescales are available:

Can I trust this data?

The Cawthron Institute has worked alongside regional councils to verify the processes and methods used for data collection, laboratory analysis of samples collected and the statistical analysis and interpretation of the results presented.

If all Cawthron ticks are green, then you can trust this data. However, if one or more ticks are orange, then conclusions should be treated with some caution.

For more details on each tick, see our 'Can I Trust This Data?' Factsheet.

Can I trust the data?
Data Collection

All samples were collected using approved field protocols and have been analysed in accredited laboratories. Therefore the data shown here has been collected and analysed following best practice.

State

This site is not sampled during high flows so the data shown only represents base flow conditions. Proposed national guidelines recommend sampling during both low and high flows to get a full picture of water quality at the site.

Trend - Adjustment for flow

This data is not flow adjusted. National guidelines suggest that flow-sensitive variables are flow 'adjusted' before trend analysis. Therefore, any trends shown here may be affected by variations in flow across sampling occasions.

Bacteria

E. coli
State
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Trend
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Clarity

Clarity

Black disc
State
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Trend
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Clarity

Turbidity
State
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Trend
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Nitrogen

Nitrogen

Total Nitrogen
State
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Trend
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Nitrogen

Total Oxidised Nitrogen
State
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Trend
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Nitrogen

Ammoniacal Nitrogen
State
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Trend
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Phosphorus

Phosphorus

Dissolved Reactive Phosphorus
State
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Trend
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Phosphorus

Total Phosphorus
State
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Trend
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Download Data

.ZIP file of indicator readings for all sites in New Zealand
Download
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