New Zealand Hydrogeological Unit Map
Map
This hydrogeological unit map GIS dataset provides a set of overlapping stacked polygons that represent hydrogeological units (i.e., aquifers, aquitards, aquicludes and basement) developed in a nationally-consistent manner.
Overview
Hydrogeological units are defined as a combination of unit, geological age and lithology and the following hydrogeological type, mapped at the national scale: aquifers, aquitards, aquicludes and basement, and represent the 3D structure of New Zealand’s aquifers. This dataset provides a consistent framework to connect the considerable information on groundwater systems held by regional regulatory authorities. The mapping approach includes consultation with regional experts and water managers to ensure the produced maps are fit-for purpose.
This dataset was initially prepared for the Ministry for the Environment (White et al. 2019) and is further developed by GNS as part of the Groundwater Strategic Science Investment Funds programme. To enable collaborative refinement of this national dataset, time-stamped interim datasets are made available, alongside a release note documenting unit modifications. Further releases are anticipated as mapping progresses in other hydrogeological systems.
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About the GIS dataset
The New Zealand Hydrogeological-Unit map (HUM) dataset consists of the following complementary files:
- A GIS dataset covering either the north island (‘NZ_hydrogeological_unit_stacked_north_island_20231115.shp’) or the south island (‘NZ_hydrogeological_unit_stacked_south_island_20231115.shp’;
- ‘HUM_data_dictionary_20231115.csv’ which summarises attributes, values and descriptions from the GIS dataset;
- ‘HUM_unit_list.csv’ which lists HUM unit names;
- ‘HUM_facies_list_20231115.csv’ which lists facies names;
- ‘HUM_facies_model_list_20231115.csv’ which lists current facies model and their definition criteria.
- ‘release_note_20231115.docx’ which contain metadata information about the GIS dataset
Each polygon is attributed the following attributes (attribute names in the dataset in brackets):- unique identification number (HUM_ID),
- unique name (HUM_name),
- hydrogeological unit type (HUM_type),
- geological era (HUM_era),
- geological age descriptor (HUM_age),
- lithological type (HUM_lith),
- lithological descriptor (HUM_rock),
- polygon-specific depositional facies name (facies),
- where applicable, hydrogeological system-specific reference to the representative volcanic facies model (volc_model),
- where applicable, hydrogeological system-specific reference to the representative sedimentary facies model (sed_model),
- polygon-specific outcrop indicator (outcrop),
- polygon-specific vertical sequence order, from younger to older unit (order),
- unique polygon id (poly_ID).
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Download the dataset
The NZ Hydrogeological Unit Map dataset is available in separate downloads for the North Island and the South Island.
Disclaimer and license applies
- Download NZ Hydrological Units for the North Island 20231115 version (ZIP, 69 MB)
- Download NZ Hydrological Units for the South Island 20231115 version (ZIP, 59 MB)
If you wish to access the superseded version, it is available here(external link) (Ministry for the Environment data portal).The 2019 report describing the development of this dataset is accessible here(external link) (Ministry for the Environment publication webpage).
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Terms of use
This dataset is provided under Creative Commons C BY 4.0.0(external link)
Where the dataset is used in a figure, GNS Science requests attribution in the following manner: © GNS Science 2023.
Where reference to the dataset is to be included in a reference list please cite White et al., 2019 (Revised 2023).
Cite as: White, P.A.; Moreau, M.; Mourot, F.; Rawlinson, Z.J. 2019 (Revised 2023). New Zealand groundwater atlas:hydrogeological-unit map of New Zealand. Lower Hutt (NZ): GNS Science. [86] p. Consultancy Report 2019/144.