Salinisation

Dryland Salinisation, the build up of salts within the soil thatcan lead to severe vegetation loss, is spreading throughout large area of the globe. Airborne Electromagnetic (AEM) geophysics can play a fundamental role in the management of salinization affected areas, allowing rapid mapping their extent and monitoring over time the effect of remediation plan eventually put in place. Results of the AEM survey can also be used to produce water salinity maps and other by-products in cooperation with the client.

The image represents the near surface average resistivity map from the Bookpurnong area, in South Australia, derived inverting SkyTEM data. This area, like many others in the Darling-Murray catchment zone, is severely affected by salinisation. Click map to enlarge.

Click here to find the Exploration Geophysics article published this year about this case study.

Shallow depth salinisation requires specific AEM survey design and data inversion strategies, such as the constrained inversion technique. This methodology, which is readily applied in the Aarhus Workbench, spreads information between neighboring soudings, allowing a better resolution of model parameters that would be locally poorly resolved.

 Salinisation of coastal aquifers is another frequent problem in large portions of the world, where natural and human driven processes drive the penetration of seawater into groundwater. At the same time, inland aquifers contaminated by industrial activities may lead to offshore pollution. Airborne EM is a powerful tool for mapping sea water intrusion, and for understanding surface groundwater interactions in coastal areas. See for example these expanded abstracts from AEM 2008 in Helsinky (HEM survey over part of Banda Aceh coast), and from ASEG 2009 in Adelaide (SkyTEM data from Denmark and Fugro's Resolve HEM system's data from Australia).   

Check out the promising application of AEM over lagoons from this study over the Venice lagoon.