Assessment of Variability in Glacier and Snow Melt Runoff for Alaknanda River Basin Using Spatially Distributed Snow and Glacier Melt Runoff Model (SDSGRM)

Evaluating snowmelt, glacier melt, and rainfall-induced runoff is required to understand hydrological dynamics in glaciated basins. However, challenges arise due to their remote nature and scarce data availability. The Spatially Distributed Snow and Glacier Melt Runoff Model (SDSGRM) was applied in the Alaknanda River Basin to estimate streamflow, incorporating daily variables such as temperature, precipitation, snow cover, and wind speed. Model calibration (2006-2010) and validation (2012-2014) utilized multiple melt depth estimation techniques. During calibration, Modelling Efficiency (ME) values ranged between 0.51 and 0.77, with R² surpassing 0.6, while the Coefficient of Residual Mass (CRM) varied from -0.01 to 0.2. Validation exhibited comparable results, with ME and R² remaining above 0.5 and 0.6, respectively, and CRM fluctuating between -0.08 and 0.18. The energy balance method generally outperformed the others. Average runoff contributions were 93.19% from Rainfall Water Yield (RWY), 6.58% from Snow Water Yield (SWY), and 0.17% from Glacier Water Yield (GWY). Given its acceptable performance, SDSGRM proves to be an effective tool for analyzing the runoff contributions in glaciated, data-scarce basins and assessing climate change's influence.