With the dipole method, we survey on a multitude of different natural materials. Usually, we walk on gravel or sand, but sometimes it’s clay or dirt, and I have even had projects on salt. In all cases, adjustments are necessary depending on the electrical conductivity of the materials used, but it’s generally fine given the homogeneity of the cover layer.
On the other hand, it does happen that the work sequencing fails and that waste is already stored on the drainage and protection layer, or the owner measures a flow in a double-lined system once the operation has already started and wishes to find the leak(s) despite the presence of waste, even if it is contaminated waste.
In this case, the dipole method takes on a whole different meaning because it is necessary to equip oneself with respirators, suitable boots, and to allow time to thoroughly clean the equipment. I have even worked at a nuclear site and my work boots needed to be incinerated due to their radiation level, even after cleaning.