In the present study, for hydrological modeling of Komah basin with an area of 1680 Km2, three digital elevation models with 10, 30 and 90 meters as inputs of the SWAT model in a constant condition were tested. The main objective of this research is to investigate the effect of digital height elevation model on output of SWAT model in simulation of runoff flow and physiographic characteristics of basin. The model were calibrated with data of runoff hydrometric stations of 2010 to 2014 and validated with data of 2014 to 2016. For this purpose, the coefficient of determination and Nash–Sutcliffe were used to eva‎luate the model's efficiency. The results of the Roodabad station were acceptable, so that for the digital elevation model 10, 30 and 90 meters in the validation period, the coefficient of determination was 0.44, 0.41 and 0.37 respectively, and the coefficient of Nash–Sutcliffe was 0.41, 0.32 and 0.31 and in the calibration period, the coefficient of determination was 0.33, 0.31 and 0.35, respectively, and the Nash–Sutcliffe coefficient was equal to 0.41, 0.20, and 0.20. However, the results of the model test are not satisfactory in different situations, but the comparison of the results shows the sensitivity of the model in terms of different DEM accuracy. The physiographic results of the DEMs did not differ much from each other, although the 10-meter-high digraph model had a much higher accuracy. One of the reasons for the model's weakness in simulating the flow in some months of the year is the weak simulation of snow melting, the incompatibility of model assumptions in the flow of the frozen and saturated layers, the low number of flow data and the lack of data needed to simulate groundwater.

9/22/2018 12:00:00 AM

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وحيد عاشوري