Ali Talebi; Shahrbanoo Abbasi Jondani
Abstract
WEPP model needs a great deal of input data. Identifying the model’s sensitive parameters andtheir prioritization increases the accuracy and efficiency of the model. On the other hand, WEPPmodel can simulate processes affecting on runoff, erosion and sediment throughout the year. Thus,model sensitivity ...
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WEPP model needs a great deal of input data. Identifying the model’s sensitive parameters andtheir prioritization increases the accuracy and efficiency of the model. On the other hand, WEPPmodel can simulate processes affecting on runoff, erosion and sediment throughout the year. Thus,model sensitivity must vary based on the storm occurrence time and parameters value in differentsections of the year. To prove this assumption, two spring and autumn storm events related to 2008were selected and sensitivity analysis of the WEPP model was done in three plots with differentconditions in Sanganeh watershed. For sensitivity analysis, the OAT method was used andsensitivity degree of parameters was calculated. Obtained results show that the rate of sand is themost sensitive parameter of WEPP model. This parameter was followed by other parameters likeclay percent, effective hydraulic conductivity, height and intensity of rainfall, day degree ofgrowing, growing season and percent of growing season when leaf area index decreases. Mostvariations are observed in prioritization of sensitive parameter in the plant/ management file. Inmost cases, sensitivity degree of these parameters in autumn event comparing to the spring eventhas significantly reduced in all plots. In general, obtained results show that the rate of sensitivity ofthe WEPP model to different parameters varies during the time. Hence, for using this complexmodel in regions with data limitation, the user must be aware to this issue that regarding storm time,which parameter is more sensitive in the pilot area and need to be carefully measured in the field.
