ClimateChange Assessment Guide.pdf - University of Waterloo

Appendix E E-21Subwatershed 19 Case Study2.5Mm32.01.51.00.5SimulatedObserved0.0JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberFigure 3-6: Simulated and observed monthly total streamflow for Subwatershed 19, 2001 to 2004.Figure 3-7 shows the daily simulated and observed streamflow rates at the Melville gauge site for 2002 as anexample. The daily flows are displayed on a logarithmic scale so that flow rates can be compared in relative termsthroughout the full range of flows. Simulated streamflow tends to reflect observed rates and trends in a reasonablemanner. Significant differences exist for individual events, especially during winter, but maximum and minimum flowstend to be in reasonable agreement.10SimulatedObservedm3/s1112234456678899101111120.1Figure 3-7: Simulated and observed daily flow rates at the Melville gauge, 2002.Figure 3-8 shows the flow frequency distributions for the simulated and observed time series of flows, for thecalibration period. The correspondence between simulated and observed flow frequencies confirms the model’s abilityto simulate subwatershed scale hydrologic response. Simulated results reflect observed storm or melt eventresponse and extended low or baseflow periods. The overall mean flows compare closely. Good agreement in theseterms indicates that the model calibration reflects the long-term averages as well as the occurrence of minimum andmaximum flow regimes within the time series. Validation period correspondence in this regard is also good.