ClimateChange Assessment Guide.pdf - University of Waterloo

More documents

Recommendations

Info

E-12Guide for Assessment of Hydrological Effects of Climate Change in Ontario The hydrology of Subwatershed 19 is complex. In addition to natural hydrologic processes and sources of water inthe system there are several human influences with significant consequences. These include groundwater pumpingfor municipal potable water supply, wastewater discharges into the Credit River, storage in Island Lake with controlledoutflow and the many local incremental effects of agricultural development, aggregate extraction and urbanization.Tier Two Stress Assessment studies have determined that there is a risk of water supply shortages in the future,following further urban growth in the subwatershed (AquaResource, 2008).Because of the hydrologic complexity and the acute need for effective water management in the area, a linkedmodelling approach has been selected for the Subwatershed 19 Tier Three Local Area Risk Assessment study. Thisapproach has been selected for its inherent rigour and comprehensiveness. The approach will take advantage of thestrengths of two discrete models, a streamflow model and a groundwater model, to assess water resources. Thisapproach will also be employed in the climate change impact assessment.The streamflow generation model is used to generate continuous long-term time series of streamflow at sitesthroughout the subwatershed. The model partitions precipitation and snowmelt into runoff and groundwater recharge,while accounting for losses due to evapotranspiration (ET). Surface runoff and groundwater discharge are routedthrough the tributaries and Island Lake to the mouth of the subwatershed. The model is spatially and temporallydetailed so that it accounts for the varied landforms and physiography in the area and can capture the dynamicresponses in the system accompanying ever changing weather conditions and human activities. While streamflowmodels typically include a groundwater component to generate baseflow in streams, this component is typicallysimplistic and not capable of reflecting the temporal and spatial complexity of the groundwater system.The groundwater model, with a good three dimensional representation of the groundwater system (including pumpingwells), generates water levels and outflow to streams on a long-term steady state and transient basis. This modelrelies upon the spatially and temporally detailed recharge estimates provided by the streamflow model. In turn, thegroundwater model provides estimates of major groundwater transfers across subwatershed boundaries to thestreamflow model. Knowledge of these subsurface transfers is critical to configuring the streamflow model so that itcan account for all of the sources and sinks of water in the study area. This process needs to be iterative in thepreliminary stages of model calibration so that reasonable estimates of recharge and groundwater movement can betransferred between models.CVC has experience with both types of simulation models and the capacity to support the model development.Therefore this approach is realistic considering the available resources and technical capacity and providessufficiently detailed simulation results to adequately reflect the sophisticated nature of the study area. CVC conducted a formal model selection process for the Water Quality Strategy (WQS) (CVC, 2008). The modellingobjectives of the WQS were similar to the Subwatershed 19 study, at a different spatial scale. That selection processconsidered CVC needs into the future and sought to identify technologies that could become part of the core toolboxassociated with watershed assessment. The tool selected, the Hydrological Simulation Program – FORTRAN (HSP-F) (Bicknell et al., 2001), is relevant to the Subwatershed 19 study, has the capabilities to achieve the modellingobjectives and technical requirements and has been successfully applied across the whole Credit River Watershed forhydrologic and water quality assessments. Furthermore, particularly relevant to climate change impact assessments,
Appendix E E-13Subwatershed 19 Case StudyHSP-F utilizes sub-models for winter processes (i.e., snow accumulation and melting) and year roundevapotranspiration that are each sensitive to several climate parameters and thus, are sensitive to climate change. The computer code MODFLOW was selected to develop the numerical groundwater flow model for the Tier ThreeLocal Area Risk Assessment. MODFLOW is a three-dimensional, saturated, finite difference groundwater modellingcode that was first developed by the United States Geological Survey (USGS). Additional information on MODFLOWcan be found in McDonald and Harbaugh (1988) and Harbaugh and McDonald (1996). This code has been usedextensively for water budgeting and various other uses worldwide. The groundwater flow model was developed withthe aid of Visual MODFLOW, a graphical user interface developed by Waterloo Hydrogeologic Inc. (WHI, 2005).The model area of a MODFLOW model is divided horizontally and vertically into a discrete set of square orrectangular blocks or cells, with each cell representing a discrete horizontal and vertical unit of porous media. Eachmodel cell has specified hydraulic properties (hydraulic conductivities, storage parameters, etc.) that are assigned andremain constant throughout the model simulation. The initial selection of model properties are based on theconceptual understanding of the geology and hydrogeology of the study area (refer to Section 2.3 and 2.4) andrefined through the model calibration process.MODFLOW directly simulates the hydraulic head (i.e., groundwater level) within each cell. Groundwater flowvelocities and rates can be calculated from these heads using the hydraulic properties. The hydraulic head and flowthrough each cell within the model can be calculated in either steady state, which is used to simulate equilibriumconditions, or in transient mode, which is used to simulate the systems response to changing stresses that may occurover a given period(s) of time.
Page 3:
Guide for Assessment of HydrologicE
Page 7 and 8:
Executive SummaryExecutive Summaryi
Page 9 and 10:
Executive Summaryv2007c). The magni
Page 11 and 12:
Executive Summaryviiwatering needs
Page 13 and 14:
Executive SummaryixSummary GCM cont
Page 15 and 16:
Executive SummaryxiStep-by-step Gui
Page 17 and 18:
Table of ContentsTable of Contentsx
Page 19 and 20:
Table of Contentsxv6.5.7 Compare Al
Page 21:
Executive SummaryxviiTable 6.6 Scen
Page 24 and 25:
Guide for Assessment of Hydrologic
Page 26 and 27:
Page 28 and 29:
Page 30 and 31:
Page 32 and 33:
Page 34 and 35:
Page 36 and 37:
Page 38 and 39:
Page 40 and 41:
555
Page 42 and 43:
Page 44 and 45:
Page 46 and 47:
Page 49 and 50:
Estimating Future Local Climates4.
Page 51 and 52:
Estimating Future Local Climates29c
Page 53 and 54:
Estimating Future Local Climates31
Page 55 and 56:
Estimating Future Local Climates33
Page 57 and 58:
Hydrological Impacts5. Hydrologic I
Page 59 and 60:
Hydrological Impacts375.1.2 Toronto
Page 61 and 62:
Hydrological Impacts39frequency of
Page 63 and 64:
Hydrological Impacts41for clouds to
Page 65 and 66:
Hydrological Impacts43mid-winter me
Page 67 and 68:
Hydrological Impacts45reduce the st
Page 69 and 70:
Climate Change Assessment6. Climate
Page 71 and 72:
Climate Change Assessment49• Plan
Page 73 and 74:
Climate Change Assessment51This app
Page 75 and 76:
Climate Change Assessment53inflow/o
Page 77 and 78:
Climate Change Assessment55As the c
Page 79 and 80:
Climate Change Assessment57Guidance
Page 81 and 82:
Climate Change Assessment59Further,
Page 83 and 84:
Page 85 and 86:
Climate Change Assessment63Table 6.
Page 87 and 88:
Page 89 and 90:
Climate Change Assessment67The mean
Page 91 and 92:
Page 93 and 94:
Climate Change Assessment71Figure 6
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Climate Change Assessment776.4.4 De
Page 101 and 102:
Climate Change Assessment79change f
Page 103 and 104:
Climate Change Assessment81referenc
Page 105 and 106:
Climate Change Assessment83• Sele
Page 107 and 108:
Climate Change Assessment854. STMND
Page 109 and 110:
Page 111 and 112:
Climate Change Assessment89When com
Page 113 and 114:
Climate Change Assessment91charts i
Page 115 and 116:
Climate Change Assessment93With cli
Page 117:
Climate Change Assessment956.7.2 Fu
Page 120 and 121:
Page 122 and 123:
Page 124 and 125:
Page 126 and 127:
Page 128 and 129:
Page 130 and 131:
Page 132 and 133:
Page 134 and 135:
Page 137 and 138: Appendix A A-1Watershed and Receivi
Page 139: Appendix A A-3Watershed and Receivi
Page 143 and 144: Appendix B B-1GCM Modelling GroupsT
Page 145: Appendix CGCM-Based Change FieldAss
Page 148 and 149: C-2Guide for Assessment of Hydrolog
Page 156 and 157: C-10Guide for Assessment of Hydrolo
Page 169: Appendix DRCM and GCM Data Conversi
Page 172 and 173: D-2Guide for Assessment of Hydrolog
Page 175 and 176: Appendix E E-1Subwatershed 19 Case
Page 185: Appendix E E-11Subwatershed 19 Case
Page 231: Appendix E E-57Subwatershed 19 Case
show all

ClimateChange Assessment Guide.pdf - University of Waterloo

Create successful ePaper yourself

Delete template?

Save as template?