ClimateChange Assessment Guide.pdf - University of Waterloo

Appendix E E-23Subwatershed 19 Case StudyAll municipal pumping wells that lie within the modelled area were simulated using specified flux boundary conditions.The simulated pumping rates varied depending on the model simulation (e.g., long-term steady state, transientpumping test simulation, model verification).Numerical groundwater flow models are typically calibrated by systematically adjusting the model input parametersand boundary conditions to determine the optimum match (within an acceptable margin of error) between the modelpredictedresults and field observations. The model’s ability to represent observed conditions is assessedqualitatively to assess trends in water levels and distribution of groundwater discharge, and quantitatively to achieveacceptable statistical measures of calibration. The model calibration process in this study included calibration tosteady state conditions (Figure 3-9), a transient calibration to a 44 day pumping test, and it was subsequently verifiedusing average monthly reported municipal pumping rates and recharge data from 1990-2006 (Figure 3-10). Thecalibration process is iterative and calibrating to two different datasets helped refine the understanding and decreasethe uncertainty with the model input parameters.Figure 3-9: Subwatershed 19 MODFLOW calibration to groundwater elevations.