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MAPPING ZONES OF SALINE GROUNDWATER DISCHARGE USING NANOTEM: RIVER MURRAY, SOUTH AUSTRALIA
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 19th EEGS Symposium on the Application of Geophysics to Engineering and Environmental Problems, Apr 2006, cp-181-00004
Abstract
Salinisation of the River Murray in South Australia has been a constant threat to this vital water resource. River salinity, a consequence of discharging saline groundwater, is being limited through the implementation of salt interception schemes, where numerous water bores were installed along the river bank to lower groundwater levels and reduce discharge. The efficient removal of this water relies on our ability to locate areas of salt accession to the river. This study shows the use of in-river NanoTEM to map the resistivity of the river sediments. Following a ground validation exercise, which included the collection of saturated sediment cores and subsequent laboratory analyses, it was concluded that variations in the observed resistivity response were associated with changes in salinity. Together with hydrological information, conductive areas surveyed along the river were interpreted as zones of salt accession whereas the resistive areas were zones where fresh river water recharged the underlying sediments.