ClimateChange Assessment Guide.pdf - University of Waterloo

E-10Guide for Assessment of Hydrological Effects of Climate Change in Ontario The following temporal aspects are proposed for this assessment:• The hydrologic results of this study are most relevant in terms of daily, monthly, seasonal and annualstreamflows as well as monthly, seasonal and annual water balance terms (i.e., evapotranspiration, runoffand recharge). This temporal resolution can be achieved in the streamflow modelling using hourly time steps.This time step is also the most frequent reporting interval for available meteorological time series. Thegroundwater flow model utilizes time steps that range from 3 days up to 8 days. The groundwater flow modelinvolves many more computations than the streamflow model and as a result, a longer time step is required tocomplete a long-term simulation. In addition, groundwater processes are much slower than surface waterprocesses and can therefore be well represented using this longer timestep.• Calibration and validation periods for streamflow modelling include the period 2000 to 2006. The year 2000 isnot included in the summary of results as this is treated as a model spin-up year. A longer period ofcalibration and validation would encompass periods of transience in subwatershed land use, water pumpingand wastewater release and therefore the period is limited in this respect.• The simulation time period for all climate scenarios is 30 years. The existing condition includes the period1960 to 1990, with 1960 discarded as a model spin-up year. The period 1961 to 1990 corresponds to astandard normalization period used by Environment Canada to summarize climate. This time period is knownto have experienced minimal climate change, compared with the period following, i.e., 1991 to the present.• Future climates will be selected from the 2050s period. This is defined by summarizing climate for thenormalization period 2041 to 2070. This period is selected since significant climate change is expected tooccur in the years leading to this period. Table 1-1 lists the type of information required for modelling and the relevant locations and temporal factors.Table 1-1: Information requirements summary for Subwatershed 19.