River water quality modelled, state, 2013–2017

16 April 2020: Subsequent to publication in April 2019 we discovered two small errors with this dataset. These included:

• Errors in the coordinates of some sites and their associated metadata (such as landcover and elevation).
• Errors in our calculation of dominant landcover.

In addition, flow data from TopNet has also been updated.

These changes have a minor impact on overall results. These changes have have been corrected, and are republished here, as part of the Our freshwater 2020 release.

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IMPORTANT INFORMATION

1) The main (cleaned) dataset is structured by each row having a nzsegment and np_id combination. A large dataset (~ 1 GB) has resulted, due to the inclusion of the ANZG/NOF columns and the 10 different np_id values. There are ~ 6 million rows to this dataset, however a 32-bit version of Microsoft Excel will only display/download ~ 1 million rows. A DBMS, statistical or GIS application is needed to view the entire dataset.

2) A smaller raw dataset (see attachments) is provided which structures each row relating to a river segment and drops the ANZG/NOF columns.

3) The attached metadata/date quality report provides further information on the NOF, ANZG and the "McDowell meet/doesnt meet" attachment.

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This dataset contains ten parameters of water quality based on measurements made at monitored river sites:

• Nitrate-nitrogen
• Ammoniacal nitrogen
• Ammoniacal nitrogen (adjusted)
• Total nitrogen
• Total phosphorus
• Dissolved reactive phosphorus
• Water clarity
• Turbidity
• Escherichia coli
• Macroinvertebrate community index These parameters are used to measure:
• Modelled median values for all of New Zealand’s river length for the period 2013 to 2017
• For selected indicators, how the modelled values compare to the National Objectives Framework (NOF) (MfE, 2017) bands related to ecosystem health and human health for recreation, and to expected concentrations in natural conditions, as shown by the default guideline values in the Australian and New Zealand guidelines for fresh and marine water quality (ANZG, 2018)

More information on this dataset and how it relates to our environmental reporting indicators and topics can be found in the attached data quality pdf.

Summary report available at www.mfe.govt.nz/publications/fresh-water/spatial-m...