Lysander has defended his Ph.D. thesis and finally received the obligatory hat, kissed the beautiful Gaenseliesel, and showed off his climbing skills 😉
His work has strongly contributed to a better understanding of recharge mechanisms in large karst aquifers such as the Western Mountain Aquifer in Israel/Palestine. While long-term water security and management practices often rely on either hydrological indicators and/or simple water balance approaches to estimate water availability in time and space, karst systems with thick vadose zones are trickier to handle. The strong contrast in hydraulic properties and short- and long-term reaction patterns to infiltration require sophisticated modeling tools that work at a process-based level and at the same time can handle the large amounts of data and in this case huge catchment size of about 9000km2. Lysander demonstrated that the parallelized HydroGeoSphere model can simulate the complex infiltration dynamics through a multi-continuum vadose zone and a phreatic domain and showed the importance of the vadose zone as a long-term water storage. Specifically with respect to hydrological surface indicators of drought, the large depth of the vadose zone implies that such detailed investigation methods are required to provide robust estimates of water availability and potential drought occurences.
