Evaluation of Impacts of Climate Change on Water Availability in Umiujaq, Nunavik

Abstract

Water is key in climate change adaptation. The impacts of climate change will primarily manifest themselves through water, with changes in the frequency and intensity of extreme hydroclimatic events such as floods and droughts. Understanding climate change influence is crucial for assessing future water availability and developing sustainable management plans. Vulnerability to these changes differs by region and community, geographic location, nature of climate change impacts, and human factors. The Nunavik region in northern Canada is experiencing some of the most rapid changes in climate in the world, with disproportionately large temperature increases, alterations in precipitation regimes, and thawing of permafrost, among others. This investigation aims to evaluate the impact of climate change on water availability in the Umiujaq community (Nunavik) and propose strategies to reduce the effects of these impacts. In order to achieve these goals, a hydrological model of the basin has been developed and calibrated using the Soil and Water Assessment Tool (SWAT), satellite and local data, and the SWAT Calibration and Uncertainty Programs (SWAT-CUP). Due to a lack of data, a model was first developed for the Grande Riviere de la Baleine watershed (Kuujjuarapik) and then transposed to Umiujaq. The hydrological model was successfully calibrated and validated (NSE = 0.81, RSR = 0.43, PBIAS = 5.2: NSE = 0.68, RSR = 0.56, PBIAS = 0.9). Then, the model was forced with Canadian downscaled climate data (CMIP5) under three emission scenarios (RCP 2.6, RCP4.5, and RCP8.5) to develop a quantitative analysis of the future water cycle's evolution. The results showed a slight increase in precipitation with global warming and a considerable reduction in snow content due to the higher temperatures. A faster and easier snow melting would happen yearly, bringing an earlier streamflow peak in the river. In the worst-case scenario (RCP8.5), the peak streamflow will move from June 17 to May 8 (40 days), which could result in lower water availability during the summer. To address these impacts, two strategies were analyzed: increase the storage capacity of the community and resort to an alternative water source, i.e., groundwater. The first one could be a solution in the short term, while the second one would be more reliable in the long term. However, the community is already facing difficulty in providing a reliable water supply throughout the year, so swift and concerted action from both the community and relevant authorities is of the essence in tackling this issue head-on.