Modeling of rainfall and flow in the Tigris Basin with alternative methods

In this study, a drainage network was created using the flow observation station data of Dankıran Stream, Batman Stream and Başnik Stream, located within the borders of the Tigris Basin in the Southeastern Anatolia Region, and the precipitation data received from the General Directorate of Meteorology. The Tigris basin was divided into sub-basins and the rainfall-flow relationship of the Tigris Basin was examined with the HEC-HMS hydrological model. In this study, Intial and Loss Method was chosen. The Start and Loss Method meets the water volume needed by the soil layer at the beginning of the simulation process. Later, SCS Unit Hydrograph was used as the Transform Method in the sub-basin transformation. In the next stage; For sub-basin precipitation, the Specified Hyetograph option has been activated in the HEC-HMS hydrological model. The SCS Curve Number Method was used to calculate total runoff from total rainfall and infiltration loss over time and generate the runoff hydrograph. The transformation method was calculated based on parameters such as collection and delay times and precipitation data. As a result of the simulation, the performance of the model was evaluated using statistical indices - coefficient of determination (R2), Nash-Sutcliffe efficiency (NSE), percentage deviation (PBIAS) and root mean square error ( RMSE) was evaluated using the standard deviation ratio (RSR). The findings obtained as a result of this study constitute an exemplary application in the field of applied hydrology and an opinion for the Tigris Basin.