Airborne Geophysical Data for Building a Groundwater Sustainability Plan

Airborne electromagnetic surveys (AEM) are capable of delivering high-quality subsurface data for building comprehensive hydrogeologic frameworks and the application of this method to map groundwater resources globally has increased in recent years. Water-resource managers have traditionally used borehole logs, surface geophysics and wells to gain an understanding of groundwater and its flow paths. This point source data may be scarce or difficult to obtain and requires interpolation between each data source that can introduce uncertainty in the resulting constructed model. Consider as well that a 6 inch borehole represents less than 1/millionth of one acre.

Advanced processing of airborne geophysical data with inversion and interpretation techniques can provide water resource managers with confidence in the results that can then be used to develop Groundwater Sustainability Plans. The geophysical data collected does not replace, but complements existing borehole data, thereby reinforcing the geological interpretation, which in turn leads to greater certainty of identified economical and productive drill targets. Once an area has been mapped with AEM the data can be interpreted for other targets as well, including location and extent of salt water encroachment, groundwater recharge areas, surface and groundwater connections, contaminant plumes and inputs for geotechnical and environmental engineering studies.

The paper will present data from AEM surveys carried out in California, Nebraska and Canada.