Freshwater Data

"River flow refers to the quantity of water passing a point in the river over a certain amount of time. Different rivers have different flow patterns, such as sharp peak flows following rain with low flows in between, or high spring flows from snow melt. These flow characteristics affect how much water is available for irrigation, drinking water, hydro–electric power generation, and recreational activities such as fishing and boating. River flows are also very important for maintaining the health and form of a waterway.

This dataset relates to the "Geographic pattern of natural river flows" measure on the Environmental Indicators, Te taiao Aotearoa website. "

For more information, refer to the March 2015 report: 'Hydrological indices for national environmental reporting' data.mfe.govt.nz/document/11463-hydrological-indic....

"Wetlands support unique biodiversity and provide important services. They clean water of nutrients and sediment, help dampen floods, provide habitat, and act as carbon sinks. They are also valued for their spiritual and cultural significance and as important sources of food and materials, such as flax. Draining them for agricultural and urban development has reduced their extent. Understanding this reduction provides insight into the loss of biodiversity and natural function.
This dataset relates to the ""Wetland extent"" measure on the Environmental Indicators, Te taiao Aotearoa website. "

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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This dataset measures how water quality in New Zealand’s rivers is changing over time. It contains nine parameters of water quality based on measurements made at monitored river sites in years 1990-2017:

• Nitrate-nitrogen
• Ammoniacal nitrogen
• Total nitrogen
• Total phosphorus
• Dissolved reactive phosphorus
• Water clarity
• Turbidity
• Escherichia coli
• Macroinvertebrate community index

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/water-qua....

"Wetlands support unique biodiversity and provide important services. They clean water of nutrients and sediment, help dampen floods, provide habitat, and act as carbon sinks. They are also valued for their spiritual and cultural significance and as important sources of food and materials, such as flax. Draining them for agricultural and urban development has reduced their extent. Understanding this reduction provides insight into the loss of biodiversity and natural function.
This dataset relates to the ""Wetland extent"" measure on the Environmental Indicators, Te taiao Aotearoa website. "

Wetlands support high levels of biodiversity. They provide habitat for native invertebrates, plants, fish, and bird species (eg fernbird, kōkopu, and eels), many of which live only in wetlands. Wetlands act as ‘kidneys’ and giant sponges – they clean the water of excess nutrients and sediment, control flood water and pollutants, and act as carbon sinks (removing carbon dioxide from the atmosphere). Wetlands have strong cultural and spiritual importance for Māori. They are a food source (eg eel, whitebait) and provide material for weaving (eg raupō, harakeke (flax)). Draining wetlands for agricultural and urban development over the past 150 years has led to significant wetland loss and deterioration.

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

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.

"A unit of rock or sediment is called an aquifer when it can yield a usable quantity of water.
Aquifers may occur at different depths in the same location. The map shows the areas of New Zealand’s land surface above one or more aquifers. The aquifer boundaries were described by White (2001), and some boundaries were updated by Moreau and Bekele (2015), using information provided by regional councils and from Lovett and Cameron (2015). The map has 153 polygons (aquifer outlines), some of which have more than one aquifer.
Methods for defining aquifer boundaries generally rely on knowing the locations and characteristics of productive wells, and using geological maps to identify water–bearing materials. In many cases, these boundaries are also influenced by management attributes such as regional or property boundaries, and surface water catchments (Lovett & Cameron, 2015).
This dataset relates to the ""Location and area of New Zealand’s aquifers"" measure on the Environmental Indicators, Te taiao Aotearoa website.
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Adapted by Ministry for the Environment and Statistics New Zealand to provide for environmental reporting transparency. Dataset used to develop the "Lake water quality" indicator (available at www.stats.govt.nz/indicators/lake-water-quality).

We report on eight biological, chemical, and physical lake water quality attributes based on measurements made at monitored lake sites: trophic level index (TLI), chlorophyll-a, E. coli, total phosphorus, total nitrogen, ammoniacal nitrogen, nitrate-nitrogen, and clarity.

For all attributes we report on the median values for monitored sites during the period 2016–20. For selected attributes we also report:

• how these values compare to the National Objectives Framework (NOF) bands related to ecosystem health (trophic level), toxicity, and E. coli (MfE, 2020)
• a comparison of NOF and trophic level index (TLI) bands at monitored sites with the proportion of human modified landcover in the upstream catchment area

High concentrations of the measured biological and chemical attributes or low clarity indicates poor habitats for some species of animals and plants, risks for human recreation, potential toxic effects on aquatic life, and poor overall lake health.

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 environment.govt.nz/publications/environment-aotea....

11 June 2021: A revised version of this dataset has been published to correct the terminology used to compare nitrate-nitrogen values to the 3 g/m3 guideline value. The field name has been changed from “reference_condition” to “n_n_guideline”, and values in this field will now be either “Does not exceed” or “Exceeds”, instead of “Meets” or “Does not meet”.

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20 July 2020: We corrected the data about drinking water standards for E. coli and nitrate-nitrogen in the key findings for groundwater quality.

For the five-year period 2014‒2018:

• 68 percent of 364 sites failed to meet the E.coli drinking water standards (changed from 98 percent of 145 sites failed to meet the E. coli drinking water standards)
• 19 percent of 433 sites didn’t meet nitrate-nitrogen standards (changed from 28 percent of 403 sites failed to meet the nitrate-nitrogen drinking water standards).

This indicator measures groundwater quality in New Zealand’s aquifers and how it is changing over time, based on measurements made at monitored sites. We report on nitrate-nitrogen, ammoniacal nitrogen, dissolved reactive phosphorus, chloride, conductivity and Escherichia coli (E. coli) including:

• median values for the period 2014–18
• nitrate-nitrogen median values compared to a guideline value of 3 grams per cubic metre (g/m3). This value is defined as a concentration that indicates groundwater has been influenced by industrialised agriculture and is highly likely to have been impacted by human activity (per Morgenstern & Daughney, 2012 and Daughney & Reeves, 2005).
• the proportion of samples from each site that have concentrations of nitrate-nitrogen or E. coli in excess of the Maximum Acceptable Values for protection of human health (Ministry of Health, 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.

River water quality water is valued for many reasons including ecological function and habitat, recreational value, its role in supporting people and industry, and its cultural significance. Nutrients such as nitrogen and phosphorus are essential for plant growth, however too much in rivers can lead to ‘nuisance’ growths of river algae and aquatic plants, degrading habitat. High concentrations in the form of ammoniacal nitrogen and nitrate-nitrogen can be toxic to fish and other aquatic animals. Water clarity is a measure of underwater visibility, and affects habitat of aquatic life such as fish and birds, and can also impact on aesthetic values and recreational use of rivers and streams. Escherichia coli (E.coli) can indicate the presence of pathogens (disease-causing organisms) from animal or human faeces, which can cause illness.

File contains raw data collected at regional council and NIWA monitored sites over the period 1975-2013. Fields are described as follows. Refer to Larned et al. 2015 for further details:
* nemarid ---- Unique NIWA ID
* lawaid ---- Unique LAWA ID
* rcid ---- Collection agency
* srcid ---- Region site is located in
* sflag ---- River (r) or Estuary (e)
* river ---- River name
* location ---- Name of site, assigned by collection agency
* nzmge ---- easting
* nzmgn ---- northing
* nzreach ---- REC1 segment identifier
* sdate ---- Sample date (yyyy-mm-dd)
* Q ---- Flow recorded when sample was taken (if available), cumecs
* npid ---- NIWA parameter ID (as used in Larned et al. 2015)
* lpid ---- LAWA parameter ID
* fdval ---- Parameter value (units are mg/m3, except CLAR (m) and ECOLI (n/100 mL))

For more information please see:
Larned, S, Snelder, T, Unwin, M, McBride, G, Verburg, P, McMillan, H (2015).Analysis of Water Quality in New Zealand lakes and Rivers: data sources, data sets, assumptions, limitations, methods and results. NIWA Client Report no. CHC2015-033. Available at data.mfe.govt.nz/x/Mo8VUY from the Ministry for the Environment dataservice.

This dataset relates to the "River water quality" measures on the Environmental Indicators, Te taiao Aotearoa website.

Adapted by Ministry for the Environment and Statistics New Zealand to provide for environmental reporting transparency. Dataset used to develop the "Lake water quality" indicator (available at www.stats.govt.nz/indicators/lake-water-quality).

We report on eight biological, chemical, and physical lake water quality attributes based on spatially modelled data: trophic level index (TLI), chlorophyll-a, E. coli, total phosphorus, total nitrogen, ammoniacal nitrogen, nitrate-nitrogen, and clarity.

We also report median values and TLI and NOF bands for selected attributes using spatially modelled data with predictions for 3,813 lakes in New Zealand that are larger than 1 hectare.

High concentrations of the measured biological and chemical attributes or low clarity indicates poor habitats for some species of animals and plants, risks for human recreation, potential toxic effects on aquatic life, and poor overall lake health.

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 environment.govt.nz/publications/environment-aotea....