Groundwater monitoring infrastructure: Evaluation of the shallow urban and coastal network in Ōtautahi Christchurch

Abstract

Study region: Ōtautahi Christchurch, New Zealand Study focus: Urban shallow groundwater monitoring networks are becoming widespread in New Zealand and globally. A reliable groundwater monitoring infrastructure is important to develop knowledge on water table aquifers in coastal cities like Ōtautahi Christchurch. Previous investigations have shown shallow groundwater vulnerability to salinisation and contamination in urban settings, and shallow groundwater exacerbates flooding from climate change and the impact of rising sea levels. New hydrological insights for the region: Following the 2010–2011 Canterbury earthquake sequence, shallow groundwater data acquisition and the establishment of a geotechnical database in Ōtautahi Christchurch provided unprecedented information on subsurface conditions. The installation of the groundwater monitoring infrastructure opened the field of New Zealand-based urban hydrogeological studies, including continuous measurements of groundwater levels. This study presents the hydrogeological context of Ōtautahi Christchurch, provides an overview of seismic impacts on groundwater, and documents the monitoring network’s development. Methods for assessing the monitoring network included field surveys and digital information review. The overall good condition and robustness of the network mean the dataset held by the city and regional councils should be more widely used to benefit the community. Implications for researchers and network asset managers mean that the maintenance and availability of the data should be prioritised. Records from urban shallow groundwater monitoring networks are becoming an essential source of information to manage urban water resources under climate change and sea-level rise conditions.

Keywords

• Urban groundwater
• Monitoring
• Water table
• Canterbury earthquake sequence
• New Zealand