Employing Airborne Electromagnetics for Spatial and Temporal Hydrogeophysical Monitoring: A View from Opposite Ends of the Globe
Andrea Viezzoli, Timothy Munday and anders Vest Christiansen
Event name: 24rd EEGS Symposium on the Application of Geophysics to Engineering and Environmental Problems
Session: Advances in Hydrogeophysical Monitoring
Publication date: 10 April 2011
Info: Extended abstract, PDF ( 2.12Mb )
Although the notion of hydrogeophysical monitoring of natural landscapes using multi-temporal airborne EM data sets, has been around for some time, translating this into practice has been limited by several factors, including the availability of fully characterised systems and by accurate Interpretation procedures. there is also the issue of what we term “a will” – specifically a willingness to employ hydrogeophysical methods because they are trusted to yield quantitative Information on, for example, groundwater quality. This paper examines two contrasting cultures, namely an Australian and Danish one, and considers how hydrogeophysical monitoring is being developed and deployed there. in Denmark, over a period of nearly 5 years, large portions of the country have been surveyed with AEM. Derived datasets complement a large suite of ground- based TEM measurements (> 40000 soundings), dating back to the early 1990’s. Both data sets, after Interpretation, have been used to produce a seamless output covering acquisition with different instruments and configurations, often many years apart. This was made possible through the use of a national TEM test site, against which all instrumentation, had to be calibrated prior to use. This systematic approach provides the framework for hydrogeophysical monitoring, ensuring that the long term, quantitative measurement of change is a reality. By virtue of this national approach to groundwater management Denmark is uniquely placed to employ hydrogeophysical methods in spatio-temporal Investigations. in contrast, other countries such as Australia, who have a more fragmented, regional approach to groundwater management, with jurisdiction commonly the responsibility of individual States, have seen hydrogeophysical monitoring options confined to small areas and targeted, high value, assets. An example of this is the floodplains of the Murray River, where existing knowledge regarding floodplain behaviour during and after floods is limited and hydrogeophysical methods are seen as offering the promise of elucidating process.