Modelling climate impacts on hydrologic processes in the Lake Winnipeg watershed

This paper presents results of spatial and temporal analyses of hydro-climatic regimes and simulation of climate-induced hydrologic changes in the Lake Winnipeg watershed. The hydrologic and agricultural chemical yield model, Soil & Water Assessment Tool (SWAT), was employed for the simulation of hydrologic scenarios in the Upper Assiniboine catchment of the Lake Winnipeg watershed, Canada. Analyses of future climate projections from three regional climate models (RCMs) corresponding to the SRES's A2 emission scenario, indicate that the total annual precipitation will increase by 5.5-7.5% in 2041-2070 compared to 1971-2000, while temperature will increase by 2.0-2.9°C during the same period. Hydrologic scenarios simulated with the SWAT model project consistent changes in future snowmelt driven runoff, with an earlier onset of spring snowmelt and discharge peaks. Some of the results also show increases in discharge peaks. These changes can be expected to have implications on water availability and nutrient transport regime in the Lake Winnipeg watershed.