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Abstract. In the context of changing climate and increasing waterdemand, large-scale hydrological models are helpful for understanding andprojecting future water resources across scales. Groundwater is a criticalfreshwater resource and strongly controls river flow throughout the year. Itis also essential for ecosystems and contributes to evapotranspiration,resulting in climate feedback. However, groundwater systems worldwide arequite diverse, including thick multilayer aquifers and thin heterogeneousaquifers. Recently, efforts have been made to improve the representation ofgroundwater systems in large-scale hydrological models. The evaluation ofthe accuracy of these model outputs is challenging because (1) they areapplied at much coarser resolutions than hillslope scale, (2) they simplifygeological structures generally known at local scale, and (3) they do notadequately include local water management practices (mainly groundwaterpumping). Here, we apply a large-scale hydrological model (CWatM), coupledwith the groundwater flow model MODFLOW, in two different climatic,geological, and socioeconomic regions: the Seewinkel area (Austria) and theBhima basin (India). The coupled model enables simulation of the impact ofthe water table on groundwater–soil and groundwater–river exchanges,groundwater recharge through leaking canals, and groundwater pumping. Thisregional-scale analysis enables assessment of the model's ability tosimulate water tables at fine spatial resolutions (1 km for CWatM, 100–250 m for MODFLOW) and when groundwater pumping is well estimated. Evaluatinglarge-scale models remains challenging, but the results show that thereproduction of (1) average water table fluctuations and (2) water tabledepths without bias can be a benchmark objective of such models. We foundthat grid resolution is the main factor that affects water table depth biasbecause it smooths river incision, while pumping affects time fluctuations.Finally, we use the model to assess the impact of groundwater-basedirrigation pumping on evapotranspiration, groundwater recharge, and watertable observations from boreholes.