The scientists improved a big hydrology model by adding a 2D groundwater flow part. They looked at how different aquifer properties and grid sizes affect the model's predictions of evapotranspiration, runoff, and groundwater recharge. They found that the depth of the water table is crucial for these predictions, and changing the grid size can change the results by up to 12.3%. For low groundwater flow systems, grid size doesn't matter much. This new model can help us understand how pumping groundwater for irrigation affects the water cycle.