Legacy product - no abstract available

Legacy product - no abstract available

Technical report on operational activities, including data, analysis and interpretation, for the Ti Tree demonstration study site conducted for the Palaeovalley Groundwater Project. This work was funded by the National Water Commission and managed by Geoscience Australia.

Legacy product - no abstract available

Legacy product - no abstract available

Legacy product - no abstract available

Legacy product - no abstract available

Legacy product - no abstract available

The Murray River is known to display great complexity in surface-groundwater interactions along its course, with 'gaining' sections of the river identified as sites of regional saline groundwater system discharges to the river and the adjacent floodplain. In the Lindsay - Walpolla reach of the River Murray, an airborne electromagnetics (AEM) survey acquired in a 20 km 'wide swath along the river, has enabled key elements of the hydrogeological system to be mapped. Electrical geophysical methods (such as AEM) are able to map the extent and thickness of lateral bank infiltration ('flush') zones, due to the contrast between fresh water leaking from the river and brackish to saline groundwater in adjacent sediments. This study found flush zones in the study area to be present relatively continuously to depths of 5-10m in zones of varying width (200m to <4 km). Development of flush zones to greater depths (up to 25 m) is restricted. The River is interpreted as a weakly losing reach of the river system (at the time of the AEM survey). The most extensive flush zones in the study area are associated with locks, weirs and irrigation districts. Salt mobilisation associated with the flush zones at weir pools may be an issue in terms of salt load delivery to the River Murray and floodplain. Reaches of the river where the flush zones are absent and /or significantly constricted, and similar zones in tributary creeks in the adjacent floodplain, are at higher risk of saline groundwater inflows.

A summary of the presentations and outcomes of the 5th Technical Advisory Group workshop for the Palaeovalley Groundwater project.