Impacts of changing climate and snow cover on the flow regime of Jhelum River, Western Himalayas

This study examines the change in climate variables and snow cover dynamics and their impact on the hydrological regime of the Jhelum River basin in Western Himalayas. This study utilized daily streamflow records from Mangla dam, spanning a time period of 19 years (1995-2013), along with precipitation and temperature data over 52 years (1961-2013) from 12 different climate stations in the catchment. Additionally, moderate-resolution imaging spectroradiometer (MODIS) remote sensing product MOD10A2 was utilized to analyze the change in snow cover dynamics during 2000-2013. The Pearson and Kendall rank correlation tests were used to scrutinize snow cover trends and correlation between temperature, precipitation, snow cover area (SCA) and streamflows records. Basin-wide trend analysis showed a slightly increasing tendency in temperature (tau = 0.098) and precipitation (tau = 0.094), during the years 1961-2013. The changes in streamflow indicated a positive (r > 0.12) relationship with respect to temperature but variable trends (r = -0.45-0.41) with respect to precipitation during both the winter and monsoon seasons. This indicates that temperature has a significant impact on the hydrological regime of the basin. MODIS data-based investigations suggested an expansion in SCA during 2000-2013. The changes in SCA of highaltitude zones (> 2000 m a.s.l.) depicted a stronger positive correlation with climate variables and streamflow compared with those obtained for low-altitude regions (< 2000 m a.s.l.). Overall, these results signify that highaltitude areas contribute to the streamflow largely in the form of snow-and glacier-melt during the early summer season. The streamflow is then further augmented by monsoon rainfall in the low-elevation regions during late summer.