Snowmelt Runoff Simulation During Early 21st Century Using Hydrological Modelling in the Snow-Fed Terrain of Gilgit River Basin (Pakistan)

Abstract

The indispensable water supply of major reservoirs in Pakistan, essentially depends on meltwater runoff, mainly generating from the Upper Indus Basin (UIB). The present study includes snowmelt runoff simulation within Gilgit River, basin a sub basin of UIB. Snowmelt runoff model (SRM) incorporated with MODIS remote sensing snow cover products, was selected to simulate the daily discharges and to calculate the contribution of snowmelt impact on the discharge within Gilgit River basin, during the early 21st century (first decade). Our results revealed a Nash–Sutcliffe efficiency (NSE) as R2 (0.81) and average volume difference as DV (−0.51) in observed and simulated flow. Almost 9.2% of the total basin area is covered by glacier and permanent ice cover which contributes to the river runoff during summer. We also noted that the observed efficiency of the model becomes uncertain during high flow months such as June, July and August, such ambiguity during summer was attributed to glacier-melt runoff, which generates in August by the melting of glaciers.