Ground water flow models are usually calibrated with respect to water level measurements collected at intervals of several months or even years. Measurements of these kinds are not sensitive to sudden or short stress conditions, such as impact from stormwater drainage flow or flash flood. Therefore, calibration of flow models for sites exposed to such sudden natural boundaries could produce errors, if water level measurements used for calibration have large time intervals. In this study, water levels at short intervals (15 minutes) were measured for six months at a site near a stormwater drainage canal. Rigorous calibration using the trial and error technique was conducted to obtain the model parameters for the site, which are not commonly obtained from the laboratory or field study (e.g., specific yield, storage coefficient, conductance of model boundaries, effective porosity, and ratio of vertical to horizontal hydraulic conductivity). Transient flow conditions were used to calibrate the model. The uncertainty associated with the model calibrated for the water level data measured at 15 minute intervals would be greatly reduced, as the model was calibrated for short-term stress conditions. Finally, particle tracking output from the calibrated model for the short-interval data were compared to the same from another model calibrated for water level measurements at longer intervals.