Gijsbert Cirkel studied Soil Physics and Land Management at Wageningen University. In 2014, he obtained his PhD for research on the spatial and temporal dynamics of hydrology and hydrochemistry in seep-dependent ecosystems. Since 2003, he has worked as a hydrologist on a wide range of hydrological and hydro-chemical topics. His expertise is mainly in researching hydrological and geochemical links between ground and surface water and the vadose zone and translating this to drinking water collection and nature quality. Furthermore, he works as an ecohydrological/ hydrochemical adviser at OBN research in hydrology, biogeochemistry and experimental measures for the recovery of fens in stream valleys. He has extensive experience in soil physics modelling with SWAP and Hydrus 1D/2D and setting up experimental vadose zone research, including research on transport of colloids such as viruses and bacteria through the vadose zone. Finally, he is often employed as an adviser to help with well-clogging problems in groundwater water abstraction and drainage and he is involved in the development of innovative drinking water abstraction concepts. As a guest lecturer at Utrecht University, he has lectured on groundwater protection and groundwater abstraction for the Drinking Water and Sanitation master course during 2016-2018.