This aggregated uncertainty includes factors such as measurement errors, errors in assessing the elevation of the well, scaling errors due to the 1 km model grid size, and errors due to geological heterogeneity not described by the model.[39] Figure 4 shows a comparison of observed and simulated discharges for the period 1996???2004 and 1996???1999 for discharge stations 31.13 and 25.14 located in