Application of Semi Distributed SWAT Model for Simulation of Runoff in Hablehrud Basin

Immense floods are caused by runoff from high intensity precipitation in semi-Arid regions. Nowadays, different methods are used to predict flood volumes for crisis management. SWAT is a comprehensive semi-distributed continuous model for soil and water assessment. This model has the capability to simulate hydrologic procedures in different time scales including daily, monthly and annual using physical data in the basins along with meteorological data. Also, it has capability to link to GIS too. In this research, runoff was simulated in monthly time scale in Hablehrud basin. Hablehrud is located in Semnan province with 3200 Km2 area. For simulation of runoff, primarily basic necessary data were gathered and field controls were done, then, theses data were used in the model. Calibration and sensitivity analysis was performed. Simulation were carried out for a 30 year duration period (1981-2011). Calibration was done using SWAT-cup extension. A 7 year period was used for calibration and 4 year for verification (1998-2011). Nash Sutcliff coefficient of efficiency was used for assessing the model. Sensitivity analysis were performed and sensitive parameters were determining among 32 parameters. This analysis was done in SWAT-cup which is an extension for SAWT, also t-stat and p-value were determined. NSE were 0.74 and 0.63 for calibration phase and verification phase, respectively.  We can conclude sensitive parameters are: SFTMP, SMTMP, GW-DELAY and ESCO in Hablehrud basin.