New Zealand Groundwater Quality

2007 - 2016
Funder: Ministry of Science and Innovation
Contact: Magali Moreau-Fournier

The National Groundwater Monitoring Programme (NGMP) is a long-term research and monitoring programme operated by GNS Science in collaboration with all of NZ regional authorities. It provides:

• A national perspective on groundwater monitoring used to define “baseline” groundwater quality
• Associations of groundwater quality with certain causes such as anthropogenic influence
• Best-practice methods for sampling and monitoring as well as groundwater quality data interpretation.

The NGMP involves ongoing quarterly nation-wide sampling (by regional council staff) and analysis (by GNS Science) of 17 parameters from over 100 groundwater monitoring sites around New Zealand. Analysis for key water quality indicators (e.g. major ions, nutrients, metals, arsenic) is undertaken at the GNS Science Wairakei Analytical Laboratory. Interpretation of the NGMP data allows for characterisation of the quality of New Zealand's groundwater resources at the national scale, and permits differentiation of natural chemical signatures and changes from those caused by human activity.

The NGMP dataset is stored in our groundwater database, that was specifically developed for hosting geochemical and groundwater related data (as part of NGMP) following international database standards. This database was designed to serve as a national data repository and also hosts the low frequency datasets of GEONET (EQC funded). It is accessible to both the public and registered users. The NGMP dataset is a MSI-recognised Nationally Significant Database run by GNS Science, in partnership with the regional councils.

As part of NGMP, two- to three-yearly measurements of tracers, such as tritium, chlorofluorocarbons (CFCs) and sulphur hexafluoride (SF6) and analysis by the GNS Science Water Dating team to determine groundwater age distribution.

Compilation of existing hydrogeological data, with new on-site aquifer tests to evaluate key hydrogeological properties. These data will be used to map the capture zone (i.e. recharge or source area) of the groundwater that reaches each site, using a variety of modelling approaches.

Recent Outputs

Gusyev, M.A.; Tschritter, C.; Moreau-Fournier, M.; Daughney, C.J. 2011 Capture zone delineation for National Groundwater Monitoring Programme sites in the Southland region. Lower Hutt: GNS Science. GNS Science report 2011/31. 54 p. SR2011-31_NGMP_Southland_Region_Final.pdf (3.27 MB)

Daughney, C.J., Morgenstern, U., van der Raaij, R.W., Reeves, R.R. 2009. Discriminant analysis for estimation of groundwater age from hydrochemistry and well construction: application to New Zealand aquifers. Hydrogeology Journal, 18(2): 417-428, 541; doi: 10.1007/s10040-009-0479-2.

Daughney, C. J., Raiber, M., Moreau-Fournier, M., Morgenstern, U., van der Raaij, R. 2011. Use of hierarchical cluster analysis to assess the representativeness of a baseline groundwater quality monitoring network: Comparison of New Zealand’s national and regional groundwater monitoring programs. Hydrogeology Journal, in press; doi 10.1007/s10040-044-0786-2.

Guggenmos, M. R., Daughney, C. J., Jackson, B. M., Morgenstern, U. 2011. Regional-scale identification of groundwater-surface water interaction using hydrochemistry and multivariate statistical methods, Wairarapa Valley, New Zealand. Hydrology and Earth System Science Discussion, 8; http://www.hydrol-earth-syst-sci-discuss.net/8/6443/2011/hessd-8-6443-2011.pdf