Shallow transient electromagnetic method application for groundwater exploration: case study from Greece

Summary The transient electromagnetic method (TEM) survey was carried out within one of the private house area to allocate the fresh water reservoirs in Greece. There are two challenges that make the problem complex. The first is noisy settings for geophysical survey: populated area with power lines, pipes, houses etc. The second challenge is uncertainties with water-bearing reservoirs. According to geological settings and water-bearing reservoirs location, geophysical survey had to maintain penetration depth up to 250-300 m. For this task DC (direct current) methods are not applicable whereas induction electromagnetic sounding like Transient electromagnetic method (TEM) in the near field zone can show superior results. Therefore TEM survey was carried out. To ensure the high quality of TEM data the special algorithms of electromagnetic noise attenuation were applied. From TEM results it was found, that at a depth of about 180–280 m in the southeastern part of the study area, one can expect the presence of fresh water, and the resistance values are 80 Ω·m.