Dynamic coevolution of baseflow and multiscale groundwater flow system during prolonged droughts

•Multiscale groundwater flow systems (GWFS) interactively affect baseflow generation.•The roles of groundwater flow paths in baseflow generation are scale-dependent.•The evolution of baseflow discharge sensitivity is related to the evolution of GWFS.•The evolution of baseflow residence time is related to the evolution of GWFS.•Upstream water table disconnection affects watershed-scale baseflow generation.