Comparison Evaluation of Nash and Hybrid models Parameters Estimation Methods in Order to Model Rainfall-Runoff Process (Case Study: Alandchay Watershed)

Document Type : Research Paper



Rainfall-runoff hydrological models have been recognized as indispensable essential tools for water resources management throughout the world. In this respect, Nash and Hybrid models have been developed as rainfall-runoff models in recent years. Within the present research, the different methods were evaluated to estimate the mentioned models, parameters in Alandchay watershed in West Azarbayjan and with the models being compared with each other. To follow the purpose, Hybrid model parameter within the base of empirical method and Nash model parameters (using eight different methods) were estimated. To evaluate the capability of the two mentioned models, such statistical indices as RMSE, R2 and MAE were employed. The least error bearing indices and the high values of determination coefficient indicated the potential of the two models for modeling the flood hydrographs. A comparison of the statistical indices, values and calculated errors showed that Nash model benefited from a better performance than the Hybrid model. The mean error of peak discharge for Nash and Hybrid models were obtained 5.99 and 12.07 m3/s and while the mean error of flood hydrograph peak time for the mentioned models were recorded as 0 and 3 hours, respectively.


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