Gradient method

The heat transport by seepage currents is very effective and the temperature distribution in the subsurface is clearly influenced by the inflowing water within a short time. If the temperature difference between water and ground temperature is large enough, seepage currents can usually be clearly detected and localised by fibre-optic measurements due to their high information density. The temperature distribution in reservoirs and the subsurface reacts in a phase-shifted manner to seasonal changes in the ambient temperature, which means that the required temperature difference usually exists. This method, known as the gradient method, has proven itself in many applications all over the world to detect seepage infiltrations.