Water is an essential resource for human life and a critical component of economic development. However, access to clean and reliable water sources is often limited in many developing countries, having serious health, environmental, and economic consequences. The climate change crisis accelerates the problem with the weather becoming more extreme, resulting in more often and severe droughts and floods. In most parts of the world, groundwater can be used as a source of drinking water, but care needs to be taken to make sure the usage is sustainable, and this requires knowledge of the aquifer size and how well it is protected and recharged. Unsustainable groundwater usage leads to groundwater depletion and land subsidence, which is a serious issue.
The development of mapping technologies in the last decade has been enormous and near surface geophysics now has more to offer and should have a much more prominent role than is currently seen.
To locate and map groundwater resources, geophysical methods have been widely used on different scales, from small scale well-siting to larger country-scale mapping of hydrogeology. Among the geophysical methods used, transient electromagnetic (TEM) surveys have proven to be cost-effective, fast, and reliable. In TEM measurements, strong currents are pulsed in a transmit coil to generate eddy currents in the ground. The strength and temporal variations of these eddy currents are then measured as a voltage in a receive coil, revealing the electrical properties of the subsurface that enables the mapping of hydrogeological units.
In this talk I will give you an insight into the fantastic world of technology and solutions we have right at hand to imaging the subsurface. My focus is on groundwater problems, but the same technologies are also perfectly suited for mining exploration and geotechnical engineering. I will talk a bit about transient electromagnetics and how we engineer these instruments using state-of-the-art technology. They can be used in very simple lightweight instruments, semi-airborne drone carried solution, towed systems or fully blown helicopter systems. This is followed by an introduction to data processing where AI has a lot to offer to automate the entire geophysical data processing scheme. Finally, but now least, I will give inspiration to how these methods can make a huge difference in locating water resources in poor parts of Africa, can be used for monitoring variations in a groundwater table or can map large statewide regional aquifer systems.