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Visualising Groundwater Flow Using Time-Lapse Electrical Resistivity Tomography
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 25th European Meeting of Environmental and Engineering Geophysics, Sep 2019, Volume 2019, p.1 - 5
Abstract
We performed Electrical Resistivity Tomography (ERT) measurements around a groundwater extraction well in a field of drinking water extraction wells. Oxygen enriched water is injected in a well during short periods as a purification step to remove iron from the groundwater. The goal of the pilot is testing the performance of ERT as a monitoring tool. Cross-hole ERT measurements were performed in a time-lapse mode to link changes in resistivity to groundwater flow expressed by variations in temperature and possibly oxygen content from the treatment. We show one example of the change in resistivity over a period of 16 hours. The changes in resistivity are small, in the order of 0.5 %, but proven to be above the noise level. When the time-lapse results are visualized in a movie (instead of just one snapshot), the patterns of change are consistent and can be linked to groundwater flow. We conclude that the ERT methods is suitable to be used as a monitoring method for groundwater flow. An additional future dataset will consist of temperature measurements using fibre optics Active Distributed Temperature Sensing. The next step will be to use the information from both methods to optimize well operation.