Groundwater quality, trend, 1999-2018

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Creative Commons Attribution 4.0 International

You may use this work for commercial purposes.

You must attribute the creator in your own works.

2982
33
Added
07 Apr 2020

This dataset was first added to MfE Data Service on 07 Apr 2020.

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:

  • trends in concentrations for 10-year (2009–18) and 20-year (1999–2018) periods.

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.

Table ID 104571
Data type Table
Row count 1699
Services Web Feature Service (WFS), Catalog Service (CS-W), data.govt.nz Atom Feed

Depth to hydrogeological basement map, 2019

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Creative Commons Attribution 4.0 International

You may use this work for commercial purposes.

You must attribute the creator in your own works.

1710
37
Added
27 Jan 2020

This dataset was first added to MfE Data Service on 27 Jan 2020.

This data set provides an update of New Zealand’s depth to hydrogeological basement map. Depth to hydrogeological basement can be loosely defined as the ‘base of aquifers’; or more strictly as ‘the depth to where primary porosity and permeability of geological material is low enough such that flued volumes and flow rates can be considered negligible’. For more detail on the process and methods, see Westerhoff et al. (2019). New Zealand groundwater atlas: depth to hydrogeological basement. Lower Hutt (NZ): GNS Science. 19 p. Consultancy Report 2019/140.

A national model was used to estimate depth to hydrogeological basement. Hydrogeological basement refers to geological material with primary porosity and permeability that is low enough such that fluid volumes and flow rates can be considered negligible.

Layer ID 104446
Data type Grid
Resolution 250.000m
Services Raster Query API, Catalog Service (CS-W)

Groundwater quality, state, 2014-18

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Creative Commons Attribution 4.0 International

You may use this work for commercial purposes.

You must attribute the creator in your own works.

1241
19
Updated
11 Jun 2021

This dataset was last updated on MfE Data Service on 11 Jun 2021.

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”.

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.

Table ID 104569
Data type Table
Row count 14644
Services Web Feature Service (WFS), Catalog Service (CS-W), data.govt.nz Atom Feed

Estimated groundwater flux, 2019: Recharge

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Creative Commons Attribution 4.0 International

You may use this work for commercial purposes.

You must attribute the creator in your own works.

1147
25
Added
27 Jan 2020

This dataset was first added to MfE Data Service on 27 Jan 2020.

This set of data sets provides an estimation of groundwater flux. There are three components: Groundwater recharge: development of nationwide mean (daily and seasonal) groundwater recharge data sets through the combination of three pre-existing groundwater recharge models; Groundwater–surface water exchange: development of a national indicative groundwater discharge data set using an existing national groundwater flow model, as well as comparison with a pre-existing gaining/losing stream prediction data set; Groundwater flow: development of a national groundwater flow data set using an existing national groundwater flow model. For more detail on the process and methods, see Westerhoff et al. (2019). New Zealand groundwater atlas: Groundwater Fluxes. Lower Hutt (NZ): GNS Science. 60 p. Consultancy Report 2019/126.

Three national models of groundwater recharge in New Zealand were used (NGRM, TopNet, IrriCalc) to create a mean model of groundwater recharge. This dataset summarises the gridded groundwater recharge from this model mean for the period 2000-2015 in mm/day.

_Attachment 1: _A complementary dataset describing the standard deviation of the NZGroundwaterRecharge_mean_20002015 dataset.

Attachment 2: This dataset summarises the gridded autumn groundwater recharge from this model mean for the period 2000-2015 in mm/day. Also complementary dataset of standard deviation.

Attachment 3: This dataset summarises the gridded spring groundwater recharge from this model mean for the period 2000-2015 in mm/day. Also complementary dataset of standard deviation.

Attachment 4: This dataset summarises the gridded summer groundwater recharge from this model mean for the period 2000-2015 in mm/day. Also complementary dataset of standard deviation.

Attachment 5: This dataset summarises the gridded winter groundwater recharge from this model mean for the period 2000-2015 in mm/day. Also complementary dataset of standard deviation.

Layer ID 104447
Data type Grid
Resolution 1010.000m
Services Raster Query API, Catalog Service (CS-W)

Estimated groundwater flux, 2019: Discharge

Licence

Creative Commons Attribution 4.0 International

You may use this work for commercial purposes.

You must attribute the creator in your own works.

1085
25
Added
27 Jan 2020

This dataset was first added to MfE Data Service on 27 Jan 2020.

This set of data sets provides an estimation of groundwater flux. There are three components: Groundwater recharge: development of nationwide mean (daily and seasonal) groundwater recharge data sets through the combination of three pre-existing groundwater recharge models; Groundwater–surface water exchange: development of a national indicative groundwater discharge data set using an existing national groundwater flow model, as well as comparison with a pre-existing gaining/losing stream prediction data set; Groundwater flow: development of a national groundwater flow data set using an existing national groundwater flow model. For more detail on the process and methods, see Westerhoff et al. (2019). New Zealand groundwater atlas: Groundwater Fluxes. Lower Hutt (NZ): GNS Science. 60 p. Consultancy Report 2019/126.

A national groundwater model (NWT) was used to estimate the probability of groundwater discharging to the surface and separated into classes to encompass the uncertainty of the dataset.

Layer ID 104448
Data type Image/Raster
Resolution 250.000m
Services Catalog Service (CS-W)

Nationally consistent Hydrogeological-unit Map, 2019

Licence

Creative Commons Attribution 4.0 International

You may use this work for commercial purposes.

You must attribute the creator in your own works.

1058
52
Added
27 Jan 2020

This dataset was first added to MfE Data Service on 27 Jan 2020.

This set of data sets provides a classification of geological units in terms of their importance for groundwater flow and storage. For more detail on the process and methods, see White et al. (2019). New Zealand groundwater atlas: hydrogeological-unit map of New Zealand. Lower Hutt (NZ): GNS Science. 88 p. Consultancy Report 2019/144.

New Zealand Hydrogeological unit map (HUM) separated into aquifers, aquitards, aquicludes and basement developed in a nationally-consistent manner. This dataset includes only outcropping hydrogeological units. This dataset was also joined to the hydrogeological system dataset (Moreau et al. 2019), to provide a single polygon for each unique combination of HUM and hydrogeological system. Summary statistics of surficially mapped products are provided for each polygon (groundwater use, flow, recharge, discharge to the surface; depth to hydrogeological basement; and number of drinking water wells serving >100 people).

Attachment: New Zealand Hydrogeological unit map (HUM) separated into aquifers, aquitards, aquicludes and basement developed in a nationally-consistent manner. This dataset includes overlapping stacked polygons that represent different aged hydrogeological units.

Layer ID 104445
Data type Vector multipolygon
Feature count 1290
ElevationZ coordinates
Services Vector Query API, Web Feature Service (WFS), Catalog Service (CS-W)

Estimated groundwater flux, 2019: Flow

Licence

Creative Commons Attribution 4.0 International

You may use this work for commercial purposes.

You must attribute the creator in your own works.

426
33
Added
27 Jan 2020

This dataset was first added to MfE Data Service on 27 Jan 2020.

This set of data sets provides an estimation of groundwater flux. There are three components: Groundwater recharge: development of nationwide mean (daily and seasonal) groundwater recharge data sets through the combination of three pre-existing groundwater recharge models; Groundwater–surface water exchange: development of a national indicative groundwater discharge data set using an existing national groundwater flow model, as well as comparison with a pre-existing gaining/losing stream prediction data set; Groundwater flow: development of a national groundwater flow data set using an existing national groundwater flow model. For more detail on the process and methods, see Westerhoff et al. (2019). New Zealand groundwater atlas: Groundwater Fluxes. Lower Hutt (NZ): GNS Science. 60 p. Consultancy Report 2019/126.

A national groundwater model was used to estimate near-surface groundwater flow amplitudes and separated into four classes to encompass the uncertainty of the dataset.

Layer ID 104449
Data type Image/Raster
Resolution 250.000m
Services Catalog Service (CS-W)