CGRG Bibliography of Canadian Geomorphology
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Author : Bonsal, R.B.
Date : 2002.
Title : Climate impacts on water resources of the Western Cordillera.
Publication : Climate Change and Water Resources in the South Saskatchewan River Basin. Proceedings of the Workshop. Edited by: S.N. Kulshreshtha; R. Herrington; and D. Sauchyn. Department of Agricultural Economics, University of Saskatchewan, Saskatoon, Saskatchewan, April 2002.
Issue :
Page(s) : 109-110.
Abstract
Climate change is projected to have significant impacts on the future water resources of Canada. A particularly critical region involves the leeward slopes of the western cordillera where changes to the amount of snow and ice resources could have adverse effects not only for the cordillera region itself, but also for the downstream locations that rely heavily upon these resources. For example, the Peace-Athabasca Delta (PAD) relies heavily upon upstream water resources for the beneficial flooding of riparian ecosystems. In certain years, however, large snowpack conditions can result in flood hazards to several communities. In the context of this workshop, activities in the South Saskatchewan River basin including for example, irrigation, agriculture, municipal water supply and quality, and recreation also rely on the amount and timing of water supplies from headwaters of the cordillera. To determine impact and adaptation strategies for these downstream regions, reliable estimates of future changes and variability in the cordillera™s water supplies are required. At this time, however, there is limited knowledge regarding the impacts of future changes to temperature and precipitation on the magnitude and timing of water resources from the leeward slope region of the western cordillera. This study addresses these knowledge gaps.The simulated current (1961-90) monthly temperature and precipitation output from seven different GCMs (recommended by the IPCC for scenario impact studies) will be compared to various observed climate data sets (gridded data, observed station data, previously developed snow and ice data set) over the leeward slopes of the western cordillera. Based on the assessment, it will be determined which GCM or ensemble of GCMs best represents the current climate over the region. A series of predicted (e.g. 2x CO2) changes from the selected GCM(s) will then be applied to observed climate over the study area to produce multiple scenarios of future temperature and precipitation values at the daily scale. Note that most previous impact scenarios have relied only on monthly data but this is not a suitable time step for assessing intra-seasonal changes in snow runoff regimes. A methodology to apply daily GCM output to observed climate has already been developed at NWRI. These future daily temperature and precipitation scenarios will subsequently be used in a snowpack model (e.g. SNOWTHERM) to determine a range of possible future snowpack conditions over the study area (i.e. amount, density structure, timing of spring melt). These factors are critical for spring runoff and thus, hydrological conditions downstream. At this point, a thorough review of usable alpine region hydrologic runoff models (that incorporate daily temperature and precipitation data) will be conducted and the best model or models chosen. Key nodes representing different hydro-climatic regimes will then be selected (e.g. headwaters of the Liard, Peace, and South Saskatchewan rivers) and the chosen hydrologic model(s) used to construct scenarios of future runoff regimes over the various regions. A review of climate change impact case studies over the study area, as well as, similar regions around the world will be carried out and with the results from this investigation, the most likely scenarios of future runoff characteristics (amount, timing of spring freshet) will be determined. As this work continues, the results will be discussed with various stakeholders to determine implications for future economic and environmental activities including hydro-electric power generation, agricultural demand, extreme events, and trans-boundary (provincial and international) water agreements. In addition to reports on each sub-objective, a final summary report describing all findings and recommendations will be produced. This study will directly address the vulnerability of the primary source of flow from the western cordillera to climate change. Snowmelt from this alpine area is the dominant source of water feeding the hydroelectric and agricultural systems operating in the prairie portions of Alberta and Saskatchewan. Consultations with stakeholders regarding the nature of the projected hydrologic changes assessments will also be made: a) to identify the sensitivity of the current organizational (including trans-boundary water agreements) and physical structures to such change, b) to quantify critical thresholds in seasonal availability of water, and c) to determine potential adaptation strategies or barriers in the water-use systems.
Bibliography of Canadian Geomorphology