Integrated analysis of solute and microbial transport in surface water-groundwater systems and during river restoration via state-of-the-art tracer, modelling and inversion methods

In this PhD project, the aim is the investigation of the transport behavior of different solutes and microbes in groundwater and surface water on a wellfield scale, with the goal to improve the quantification of river-aquifer interactions with tracers and the delineation of groundwater wellhead protection zones. To this end, recent methodological developments of three separate domains will be combined: Online microbial and solute tracer monitoring (i.e., analytics), integrated hydrological flow and transport simulations (i.e., numerical flow modelling), and fully-automated model calibration (i.e., mathematical inversion). Through the combination of these recent developments, it will finally become possible to delineate protection zones for drinking water supply wells that robustly reflect the pathways and travel times of both microbial pathogens and contaminants. The current protection zone delineation approaches for drinking water wells are exclusively based on solutes and never on microbial tracers, although it is well understood that microbes travel faster than solutes and protection zones should primarily protect against microbial contamination. An important part of the project will focus on the implementation of a modified colloid filtration theory approach for microbial transport simulations in the integrated surface-subsurface hydrological model HydroGeoSphere. The project is conducted in close collaboration with Université Laval (Prof. R. Therrien), Université de Neuchâtel (Prof. P. Brunner & Prof. D. Hunkeler) and Eawag (Prof. R. Kipfer).