In groundwater hydrology, the characterization of the distribution of groundwater flow within the critical zone received considerable attention in the last decades. Our ability to quantify groundwater flow greatly controls our ability to characterize aquifers, predict contaminant transport, assess recharge and discharge, and understand biogeochemical reactions and processes occurring in the subsurface.
In this context, thermal response tests have been widely developed in the past years to estimate groundwater fluxes. Active-DTS measurements rely on distributed temperature sensing (DTS) technology, which provides temperature measurements at high spatial and temporal resolution along a Fiber-Optic (FO) cable. For Active-DTS measurements, the FO cable is electrically heated, and the temperature elevation measured during heating directly depends on the water flux and the thermal properties of the surrounding materials. Therefore, Active- DTS experiments are very useful to provide in-situ and distributed estimates of thermal conductivity of the subsurface and of groundwater flux.
In this presentation, we will explore how the method has been successfully applied in various contexts to estimate groundwater flow in different compartments of the critical zone. We will discuss the relevance of this method in understanding groundwater-surface water interactions, estimating flows within aquifers, and assessing the effectiveness of managed aquifer recharge techniques.