“…In Belgium, research projects with a focus on river-aquifer interactions have been intensively carried out in the Aa river, a typical Flemish lowland river, using a combination of multiple methods, such as heat tracer, river bed hydraulic conductivity measurements and numerical modelling approaches (Anibas et al, 2009(Anibas et al, , 2011(Anibas et al, , 2015(Anibas et al, , 2017Ghysels et al, 2018Ghysels et al, , 2021Schneidewind et al, 2016). However, these applications are limited to relatively small spatial scale studies, e.g.…”