Application of SWAT Model to Assess Land Use-Land Cover Impact on the Hydrological System of Heshkaro River in Duhok City, Kurdistan Region, Iraq

The watershed analysis and assessment of the factors affecting the surface runoff is an utmost priority for successful catchment area management. Land use and land cover are among the most important factors affecting the hydrological response of the watershed. The Heshkaro River is one of the two main rivers crossing Duhok City. The methodology of this work included the investigation of temporal variations of land use and land cover maps for the Heshkaro River for the last three decades (1986 - 2022). The supervised classification style was applied to generate the land use and land cover maps for the different types of satellite images. The SWAT model was set up to construct the hydrologic model to simulate the stream flow of this river during the specified period. The thematic layers of land use-land cover, soil, DEM, and weather parameters were initialized for the model. The daily discharge of the river was measured in the field during the rainy period of 2022. The model designed was calibrated and verified for the daily field-measured runoff. The results of calibration and validation demonstrate a good match between the observed and simulated daily flows, according to the values of R2 of 0.92, Nash Sutcliff Efficiency of 0.91, and Root Mean Standard Deviation Ratio of 0.04 for calibration and R2 of 0.85, NSE of 0.90, and RSR of 0.01 for validation. The assessment impact of land use and land cover on the Heshkaro River demonstrated a significant effect of LU/LC classes on the hydrological process in the Heshkaro River basin. The outcome of this research will provide the requirements for successful management of the Heshkaro River watershed with a guarantee of the basin's environmental sustainability.