ClimateChange Assessment Guide.pdf - University of Waterloo

E-20Guide for Assessment of Hydrological Effects of Climate Change in Ontariocalibration and validation periods. Examples of comparisons of simulated and observed streamflows and volumes areprovided below; however the full set of comparisons and a more complete analysis are provided in the Subwatershed19 report (EBNFLO Environmental, 2009).Table 3-1: Calibration and validation period comparisons.Comparison CriteriaObservedCalibration PeriodSimulatedCalibration PeriodObservedValidation PeriodSimulatedValidation PeriodMaximum Streamflow Rate, m 3 /s 4.85 3.67 6.76 3.78Minimum Streamflow Rate, m 3 /s 0.138 0.199 0.247 0.276Median Streamflow Rate, m 3 /s 0.402 0.411 0.510 0.500Annual Average Flow Volume, dam 3 15,815 16,323 20,718 20,372Average Winter* Flow Volume, dam 3 4,134 4,112 6,176 6,638Average Spring* Flow Volume, dam 3 5,264 5,410 5,115 5,652Average Summer* Flow Volume, dam 3 2,999 3,010 3,291 3,106Average Fall* Flow Volume, dam 3 3,418 3,791 4,859 5,075*Winter: Jan.-Mar., Spring: Apr.-Jun., Summer: Jul.-Sep., Fall: Oct.-Dec.Figure 3-5 displays the simulated and observed annual total outflow volumes from Subwatershed 19 for the combinedcalibration and validation periods. Three of the years agree very closely while the remaining four years displaydiscrepancies of 10% (2003) to 14% (2005). The discrepancy in total flow volume over the entire period is less,0.20%, as the errors are offsetting in the longer term.302520SimObsMm3/y1510502001 2002 2003 2004 2005 2006 2007Figure 3-5: Annual total simulated and observed outflow from Subwatershed 19, 2001-2007.Monthly total streamflow volumes are compared in Figure 3-6. In general, these compare favourably. The monthswith the largest relative discrepancies are in January, February and November. Snow accumulation and meltprocesses complicate simulation in the winter months, accounting for much of the difference noted. In addition,evapotranspiration in winter months is generally not well understood and may account for some error in overall winterwater balance. The validation period displayed similar results with the largest discrepancies in the winter months, butgood overall agreement.