Hydrological Modeling and Calibration with Swat in the Arıt Stream Basin, Türkiye

Authors : Hamed Mardanshahi, Ercan Gemici

Pages : 308-323

Doi:10.55930/jonas.1770442

View : 44 | Download : 43

Publication Date : 2025-12-31

Article Type : Research Paper

Abstract :This study develops, calibrates, and validates a SWAT2012 hydrological model for the Arıt Stream sub-basin in Bartın Province, Türkiye, to provide a reproducible baseline for analyzing streamflow regime and basin water balance under current and changing climate conditions. The model was set up in QGIS using the QSWAT interface, supported by a 25 m DEM, CORINE 2018 land use/land cover data, and FAO-based soil information. Daily precipitation and maximum–minimum temperature records for 2010–2023 were used as meteorological forcing, and potential evapotranspiration was computed using the Penman–Monteith method. Simulations were performed at a daily time step for 2010–2023, with 2010–2011 reserved as a warm-up period and model evaluation carried out at a monthly scale. Monthly outlet discharge (FLOW_OUT) at the Darıören gauging station (DSİ D13A049) was compared with observations, and calibration/validation were conducted in SWAT-CUP using the SUFI 2 algorithm. To account for the small difference between the modeled drainage area (≈130 km²) and the reported gauge drainage area (137 km²), observed discharges were scaled by the area ratio 130/137 (=0.95). Model performance yielded NSE=0.79, R²=0.84, KGE=0.71, RSR=0.46 and PBIAS=−16.9% for the calibration period (2012–2018), and NSE=0.78, R²=0.83, KGE=0.70, RSR=0.47 and PBIAS=−20.9% for the validation period (2019–2023). The negative PBIAS values indicate a tendency to overestimate mean discharge; however, the model reproduces the observed seasonal pattern and provides a consistent basis for future scenario analyses and water resources assessments in the Bartın region.
Keywords : Arıt Çayı, Bartın, kalibrasyon, hidrolojik modelleme, NSE, PBIAS

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