World Freshwater Data - Page 3

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 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

This dataset includes:

• Median values for the period 2013 to 2017
• for selected indicators, how these 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/water-qua....

This dataset measures groundwater quality in New Zealand’s aquifers based on measurements made at monitored sites. Many factors influence the quality of our groundwater. Nitrogen, which occurs naturally in groundwater, can increase in concentrations due to agricultural and urban land use, and infrastructure such as waste treatment plants. High concentrations of nitrate-nitrogen in groundwater can affect human health and the quality of surrounding rivers and lakes that receive inflows from groundwater. Ammoniacal nitrogen can cause an undesirable smell that may make groundwater unsuitable for drinking water. Natural processes in groundwater can convert nitrate-nitrogen into ammoniacal nitrogen or other forms under some chemical conditions. Surplus phosphorus drains (leaches) into groundwater as dissolved reactive phosphorus. Too much nitrate-nitrogen, ammoniacal nitrogen, and phosphorus can lead to excessive plant and algae growth where groundwater flows into surface water. E. coli in groundwater is measured in colony forming units (cfu) and can indicate the presence of pathogens (disease-causing organisms) from animal or human faeces. The pathogens can cause illness for anyone who ingests them.

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.

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 “ref_meet” 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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This dataset measures groundwater quality in New Zealand’s aquifers based on measurements made at monitored sites. Many factors influence the quality of our groundwater. Nitrogen, which occurs naturally in groundwater, can increase in concentrations due to agricultural and urban land use, and infrastructure such as waste treatment plants. High concentrations of nitrate-nitrogen in groundwater can affect human health and the quality of surrounding rivers and lakes that receive inflows from groundwater. Ammoniacal nitrogen can cause an undesirable smell that may make groundwater unsuitable for drinking water. Natural processes in groundwater can convert nitrate-nitrogen into ammoniacal nitrogen or other forms under some chemical conditions. Surplus phosphorus drains (leaches) into groundwater as dissolved reactive phosphorus. Too much nitrate-nitrogen, ammoniacal nitrogen, and phosphorus can lead to excessive plant and algae growth where groundwater flows into surface water. E. coli in groundwater is measured in colony forming units (cfu) and can indicate the presence of pathogens (disease-causing organisms) from animal or human faeces. The pathogens can cause illness for anyone who ingests them.

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.

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.

Cultural Health Index scores for a waterway is a combination measure of historical cultural use and access, mahinga kai assessment, and water quality assessment from a cultural perspective of a site on a waterway.

The Cultural Health Index scores compile this information into a classification system to provide an overall grading of the state of a site and how the state of a site on a waterway affects the mauri, the ability for tangata whenua to feed the hapu and iwi and the overall water quality for the site. These are all important indicators of the cultural health of a waterway, and are also a consideration for other cultural and recreational activities like karakia, cleansing, swimming and wading.

Water is an important source of energy that contributes to New Zealand’s energy supply and the economy. As the main source of renewable energy in New Zealand, the use of water supports the production of the electricity industry. Tracking the value of this water as a natural resource – along with land form, slope, and elevation, which all help to generate hydroelectricity – shows the economic benefits derived from water use for current and future generations. Changes in flow regimes and climate can affect these values.

We report on the value of water resources used to generate hydroelectricity. This value includes both the returns received from current use (resource rent), and expected benefits from future use (the asset value).

Flow is the volume of water passing a point over a certain time, and provides information about the availability of water for people and the environment. Overall, this affects how much water is available for irrigation, drinking water, hydroelectricity generation, and recreational activities. River flows also influence a waterway’s physical form, habitat, and ecological processes like migration, spawning, and food supply for aquatic life.

The file provides the estimated impact of upstream consents on the modelled median flow of a particular reach in the digital river network. This is calculated by upstream total consented takes by median flow.

Regional councils issue resource consents for the taking of fresh water for various purposes, including irrigation, drinking, hydroelectricity, and industry. Water can be taken from surface water or groundwater.

The file provides the primary source and primary use of the water take for each consented take.