**Author details**

**Figure 10.** scatter plot of observed versus simulated flow for validation phase.

This research allowed for the model to be examined for the Neka catchment in Iran for a pe‐ riod of 14 years. The daily rainfall and evaporation input data was tested. A fine comparison with the calculated hydrograph was obtained. The precision of this reproduction is around 0.87, 0.974 and 0.747 according to the Nash-Sutcliffe criteria, square correlations, and modi‐ fied correlation coefficient respectively. The aggregated measure (AM) was found to be 0.85 that the model performance is excellent for the validation phase. This shows that the model is suitable for using rainfall data, antecedent moisture and evapotranspiration etc and gener‐ ating runoff in a spatially rational based on the topography, land use and soil type and cre‐ ating a nominally higher precision simulation catchment for the high flows. The graphical comparison amongst observed and estimated daily flows for the 14 years of model simula‐ tion proves that the season flood hydrographs have been properly reproduced by the dis‐ tributed hydrological WETSPA model and this is achieved via reaching conclusions from using parameters based on the topography and other features of basin such as soil and land use. The consistency of the model estimation depends on how well the model"s construction is created along with how well it is parameterized. Model calibration is also essential to fix the model"s workings (8). Manual and mechanical calibrations are the two kinds of parame‐ ter estimations which are used. Mechanical calibration uses a search algorithm to check the perfect parameters and allows for numerous benefits using a physical approach. WETSPA model parameterization and the spatial format of the model parameters are estimated by employing the accessible field information to define the most essential differences. This ap‐ proach ensures that the model uses that data that has been represented in the catchment. In this research, the WETSPA model was first manually calibrated through a trial and error

**4. Conclusion and recommendation**

188 Research on Soil Erosion Soil Erosion

Ali Haghizadeh\*

Address all correspondence to: haghizadeh.a@lu.ac.ir

Department of Range & Watershed Management Engineering, Faculty of Agriculture Engi‐ neering, Lorestan University,khorramabad, Iran
