Variations in hydrological variables using distributed hydrological model in permafrost environment

The Yangtze River Source Region (YaRSR) is located in the third polar region, most threatened zone by global warming after Arctic. Permafrost covers eighty percent of total area YaRSR, while rest seasonally frozen ground. Due to a significant rise air temperature, degradation permafrost could occur. coverage river basin greatly controls its hydrology. This study focuses on hydrological modeling this environment using Soil and Water Assessment Tool (SWAT). SWAT model was calibrated (1985–2000) validated (2001–2015) daily time step. results were also compared monthly scale. An impermeable layer introduced within represent conditions. streamflow strongly dependent seasonal variation precipitation rising limb hydrograph shows melting snow, contribution soil water, thawing during spring-summer season. well restricted deep percolation water. During spring season, mainly consists surface runoff because soils. ground lead an increase groundwater flow streamflow. Ultimately, depletes as temperature gets close freezing point. describes application better analyze understand hydrology permafrost/frozen with limited data availability.