This hydrogeological system GIS dataset provide a nationally-consistent basis for hydrogeological mapping in New Zealand. Hydrogeological systems are defined here as geographical areas with broadly-consistent hydrogeological properties, and similar resource pressures and management issues. The ‘NZ_hydrogeologicalsystem_polygon.shp’ provides seven hydrogeological attributes as follows: unique name (HS_name), unique identification (HS_id), system type (HS_type), coastal information (HS_coast), aquifer overview (HS_overview), geology and age group (HS_geo_gr) and geology and age descriptor (HS_geo_age). Nine system types are identified (see figure below). The ‘NZ_hydrogeologicalsystem_boundary.shp’ attribute table identifies, the source and methods of boundary delineation. Attribute names, descriptions and values for both datasets are detailed in Moreau et al. 2019. DOI: https://doi.org/10.21420/HTZ8-Z141 Cite as: GNS Science. (2018). New Zealand Hydrogeological Systems [Data set]. GNS Science. https://doi.org/10.21420/HTZ8-Z141

This dataset contains age tracer concentrations as measured in NZ groundwater samples through time. Tracers include Tritium, SF6, CFCs, Halon-1301. These tracer concentrations enable estimation of groundwater residence time, using mixing models to convolute input to output concentrations through hydrologic systems (e.g. aquifer, river catchment). Data are continuously added, to cover more areas, and because time series data improve the robustness of age interpretation DOI: https://doi.org/10.21420/JEBK-5288 Cite as: GNS Science. (2021). Groundwater age tracer data set [Data set]. GNS Science. https://doi.org/10.21420/JEBK-5288

The Aquifer Potential Map is a preliminary map (version 1.0). This work was carried out as part of the GNS Science Groundwater Resources of New Zealand research programme, and future plans within this research programme include the refinement and update of this map. In its current form, the map is considered suitable for refining surficial aquifer boundaries on the regional scale where these boundaries have not been updated since 2001. Future updates of the dataset will reduce the uncertainty and extend the applicability of the data set. The New Zealand 1:250,000 geological map (QMAP) lithological and chrono-stratigraphic information (i.e., main rock type; geological age; and secondary rock type) were used to carry out a nationwide assessment of surficial hydrogeological units and their properties. A number of subsequent map products were produced. The work is described in Tschritter et al. 2017. One of these, the Aquifer Potential map, shows a good match with the most recent New Zealand national aquifer boundary dataset of Moreau and Bekele (2015). Additionally, the Aquifer Potential map provides a quick and simple way to communicate basic large-scale hydrogeological information. DOI: https://doi.org/10.21420/4KJH-5Z44 Cite data as: GNS Science. (2017). New Zealand Aquifer Potential Map Version 1.0 [Data set]. GNS Science. https://doi.org/10.21420/4KJH-5Z44 Cite report as: Tschritter, C.; Westerhoff, R.S.; Rawlinson, Z.J.; White, P.A. 2017 Aquifer classification and mapping at the national scale - phase 1 : identification of hydrogeological units. Lower Hutt, N.Z.: GNS Science. GNS Science report 2016/51. 52 p.; doi: 10.21420/G2101S [Link to electronic copy]

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. DOI: https://doi.org/10.21420/FQXD-VY44 Cite data as: GNS Science. (2019). Depth to hydrogeological basement [Data set]. GNS Science, Ministry for the Environment. https://doi.org/10.21420/FQXD-VY44 Cite report describing the data as: Westerhoff et al. (2019). New Zealand groundwater atlas: depth to hydrogeological basement. Lower Hutt (NZ): GNS Science. 19 p. Consultancy Report 2019/140.

• A collection of numerical model builds, scripts used in the building of the models, model outputs, and a database of measurements/observations/locations of groundwater levels, flows and chemistry data in New Zealand. These models, data and scripts can be deployed to help answer land and water management decisions across NZ. • Processed measurements of groundwater flows, levels, chemistry • Model files • Codes for processing model files for building models, history matching and uncertainty quantification. • Data and models are built for aquifer systems throughout New Zealand. Temporal extent: 1990- present DOI: https://doi.org/10.21420/2E7J-ZA37 Cite model as: GNS Science. (1990). Groundwater flow and transport models. GNS Science. https://doi.org/10.21420/2E7J-ZA37

• A collection of numerical model builds, scripts used in the building of the models, model outputs, and a database of measurements/observations/locations of groundwater levels, flows and chemistry data in New Zealand. These models, data and scripts can be deployed to help answer land and water management decisions across NZ. • Processed measurements of groundwater flows, levels, chemistry • Model files • Codes for processing model files for building models, history matching and uncertainty quantification. • Data and models are built for aquifer systems throughout New Zealand. Temporal extent: 1990- present DOI: https://doi.org/10.21420/7A4X-FZ56 Cite model as: GNS Science. (2012). Upper Motueka FEFLOW model. GNS Science. https://doi.org/10.21420/7A4X-FZ56