Large-scale hydrological models were used to study the impact of irrigation on groundwater in different regions. By coupling a hydrological model with a groundwater flow model, researchers were able to simulate water table fluctuations and depths accurately. They found that grid resolution affects water table depth bias, while pumping affects time fluctuations. The study showed that groundwater-based irrigation pumping can impact evapotranspiration, groundwater recharge, and water table levels.