Long-term hydrological simulation for the estimation of snowmelt contribution of Alaknanda River Basin, Uttarakhand using SWAT

A large population depends on water resources generated due to runoff from Himalayan River basins. They provide enough water for drink-ing, domestic, industrial, and irrigation. Also, these rivers have a high hydropower potential. A lack of in-depth studies has made it difficult to understand how these rivers respond hydrologically to climate change (CC) and, thus, impact the environment. In this paper, modelling the Alaknanda River Basin (ARB) using the Soil and Water Assessment Tool (SWAT) has been conducted to understand the hydrological response and assess its water balance components. The result shows that the basin's water yield and Evapotranspiration (ET) vary from 58 to 63% and 34 to 39% of precipitation, respectively. The average annual contribution of snowmelt to the total riverine flow will range from 20 to 24% throughout the simulation period. SFTMP, TLAPS, SMTMP, CN2, SMFMX, and GW_DELAY is found to be most sensitive at the significance level of less than 0.05, showing the contribution of the snowmelt is significant in streamflow, while delay in the groundwater will affect the contribution of surface runoff and groundwater in the streamflow. Based on the results, it is highly recommended that the spatial and temporal hydro-meteorological should be investigated in-depth.