Future water security under climate change: a perspective of the Grand River Watershed

Climate change poses a threat to the water security of the Grand River Watershed (GRW) by altering the precipitation patterns and other weather variables, which affect streamflow and freshwater availability extremely in 2022. Therefore, in this study, a Soil and Water Assessment Tool (SWAT) model for the GRW, Ontario, Canada, was used to assess the blue and green water scarcity for future periods for future sustainable management of freshwater resources in the region. The ensemble results predicted a warmer and wetter future for the GRW. The ensemble model result, when considering both emission scenarios and future periods, showed that blue water (BW) is projected to increase by 23-40% while green water storage (GWS) is projected to experience an overall decrease (2-8%). The results suggested that BW may become more scarce compared to green water in the future. The scarcity of BW is primarily due to the projected increase in population growth and water demand in the watershed. Green water scarcity in some regions indicated that changes in irrigation might be needed in the future in some parts of the watershed. The results indicate that the water resources of the GRW may become scarce and careful planning is essential for future water management.