Streamflow estimation using ArcSWAT model and SUFI-2 calibration algorithm: Example of Panjshir watershed, Afghanistan

In this study, which was carried out on data obtained from Panjshir Sub-basin in Afghanistan, a multi-station and multi-resolution hydrological simulation system was developed using ArcSWAT model in order to estimate surface runoff with high accuracy. The developed model was optimized with station-based calibration and validation cycles via SUFI-2 algorithm in this complex basin with snowmelt-based flow regime and mountainous topography. Within the scope of the research, precipitation, temperature and flow rate data for the years 2009–2017 were collected; detailed modeling was performed at 770 HRU level using Digital Elevation Model (DEM), land cover (LULC) and soil class data. The findings showed that the model exhibited satisfactory performance (R²>0.60, NSE>0.50) in both monthly and daily time steps at four flow stations; and surface runoff occurred at approximately one third of the annual mean precipitation. In addition, snow-dynamic processes were successfully modeled with elevation-based parameters such as PLAPS and TLAPS. The results obtained showed that the ArcSWAT model can produce reliable physically based estimates even in data-limited basins such as Panjshir, and these outputs provided applicable inputs for regional water management, flood control and climate change adaptation strategies. Keywords: ArcSWAT, Hydrological Modeling, Panjshir Basin, SUFI-2 Algorithm, Flow Estimation.