Modelling climate impacts on hydrologic and nutrient transport processes in the Lake Winnipeg watershed

Abstract

The quality of water in Lake Winnipeg has deteriorated due to excess nutrient loading from nonpoint sources in the watershed. According to an analysis by Jones and Armstrong (2001), total nitrogen and total phosphorus loads to Lake Winnipeg has increased by 13 % and 10 % respectively, over the last three decades. While nutrient transport from non-point sources to the lakes is driven by complex hydrologic and biochemical processes, the large-scale variability in the hydro-meteorologic regime play a key role in nutrient delivery to the lakes. Climate change is expected to influence the hydro-meteorologic regime in the Prairies region, which will also affect the nutrient transport processes. Previous studies on nutrients loading indicate that Red and Assiniboine basins are the major source of nitrogen and phosphorus loading into Lake Winnipeg (Bourne et al., 2002). Therefore, the present study focuses on climate impacts on hydrologic and nutrient transport processes in the two representative sub-watersheds of the Red and Assiniboine basins.