CR prepress abstract   -  DOI: https://doi.org/10.3354/cr01726

ABSTRACT: The information about climate change impacts on river discharge of two tributary basins of the Irtysh River, the Oba and Ulbi, is important for effective management of water resources of the Shulba reservoir in Kazakhstan. The main aim of the study was to investigate potential changes in water resources availability in the study basins. To assess the projected changes, the process-based eco-hydrological model SWIM was used under two Representative Concentration Pathway (RCP) climate scenarios obtained from the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP). Our results show an increase of mean annual temperature by 6.1 °C, an increase of average annual precipitation by 7.5%-14%, an increase of annual average discharge for the Oba (6-8%) and smaller discharge changes (below 5%) for the Ulbi at the end of the century under RCP8.5 - a scenario of comparatively high greenhouse gas emissions compared to the reference period (1981-2010). Seasonal variations are marked by a movement of the peak of discharge occurring up to a month earlier, a decrease in the duration of snow accumulation, and a lowering of discharge during the summer months. The peak discharge period is prolonged in time, and a slight increase in river discharge could be expected from October to December. Possible future changes in climate may have serious impacts on water resources, agriculture and economic development of the case study basins. The results of this study can be extrapolated to other neighboring basins in Kazakhstan with similar climatic and geophysical characteristics.