Abstract
Abstract Central Asia's water resources are characterized by strong spatial and seasonal imbalances, exacerbated by upstream–downstream dynamics. Climate change, combined with projected population growth and competing water users, will amplify water-related challenges across the region. Despite its vulnerability, Central Asia remains underrepresented in climate impact research. The main objective of this study is to provide an assessment of projected changes in water availability in sixteen river catchments by evaluating annual and seasonal changes in discharge. For this purpose, two mesoscale hydrological models (SWIM and SWAT) were set up, calibrated and validated. The future discharge for each catchment was driven by an ensemble of bias-corrected GCMs from CMIP6 based on two climate scenarios (SSP1-2.6 and SSP5-8.5) until the end of the century. The results show an increase of air temperature in all catchments, scenarios, periods and seasons. At the same time, annual precipitation generally increases, especially in winter and autumn, but summer shows a decreasing trend. Annual discharge projections show an increase in most of the catchments under both SSPs and periods, with an increase in elevation in the northern catchments. The trend increases under SSP5-8.5 until the end of the century. The most prominent finding was observed in the seasonal changes in discharge. There is a clear pattern of reduced summer flows and increased winter and spring flows due to earlier snowmelt, higher evapotranspiration, and changes in seasonal precipitation. The spring flood peak is expected to occur one month earlier in a number of catchments. Moreover, there is a clear trend of increasing flood risk, especially in the northern catchments.