Integrated modeling of snow-covered areas and hydrological processes in the Larji Sub-Basin, Himachal Pradesh, India, using SRM and SWAT models

Alpine snow is crucial for the water cycle, as the runoff and environment of arid and semi-arid regions rely entirely on these glaciers. Mountain-fed rivers provide the water for domestic, agricultural irrigation, hydroelectric power, and other uses. Due to climate variability, river catchment flows may shift, causing floods and droughts that will aggravate the economy. The trends analysis of snow-covered areas (SCAs) and glacier melt has always been critical worldwide. This study estimated the SCA using Google Earth Engine (GEE) for the Larji River basin, situated in Himachal Pradesh, from the year 2001 to 2021. The SCA varies from 0.7 to 22% in the basin. The present study highlights the effectiveness of cloud computing for assessing trends in snow cover regions in the basin. Moderate Resolution Imaging Spectroradiometer (MODIS) snow product (MOD10A1 V6 Snow Cover Daily Global 500 m product) is utilized for SCA calculation. The snowmelt estimation using the Snowmelt Runoff Model (winSRM) showed a good agreement with the measured and calculated runoff (R2 > 0.53) for the years 2019–2021. Using R Studio, the study of trends showed a decline in the pre-monsoon season, whereas other seasons show an upward trend, and there is an overall increase in the annual SCA from 2001 to 2021.