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Groundwater protection zone delineation of Matamata supply wells

TR 2014/63
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Report: TR 2014/63

Author: MW Toews, MF Moreau (GNS Science)

About this report

Matamata–Piako District Council currently use two groundwater wells for public drinking water supply to Matamata. The existing resource consent allows for a combined take of 120 m³/hr of groundwater from these wells. Waikato Regional Council commissioned GNS Science to delineate capture zones for the wells, and that delineation is the purpose of this report.

A capture zone consists of the up-gradient and down-gradient areas that will drain into a pumping well. The mapped capture zone is often defined on the basis of groundwater time of travel (TOT). This is the time that it takes for groundwater to move from the land surface, through the unsaturated zone, to groundwater and subsequently to the pumping well. The zone is then referred to as a protection zone (PZ).

Mapping of well-head capture zones for municipal supply wells is common practice worldwide to help protect the quality of municipal groundwater supplies.  

Read or download the report

Groundwater protection zone delineation of Matamata supply wells [PDF, 3.9 MB]

Contents
  Executive summary
1 Introduction
2 Regional settings
2.1 Geology
2.2 Hydrology
2.3 Hydrogeology
2.4 Groundwater chemistry
3 Capture zone delineation
3.1 Analytic element method
3.1.1 GFLOW model
3.1.2 Model calibration
3.1.3 Sensitivity analysis
3.1.4 Protection zone mapping
4 Discussion
5 Acknowledgements
6 References