شبیه‌‌سازی هیدروگراف جریان در حوضه آبریز جنگ، با مدل هیدروگراف واحد لحظه‌ای گامای معکوس و بررسی روش‌های تخمین پارامترها آن

Several formulas have been proposed for the calculation of the Instantaneous Unit Hydrograph (IUH). The concept of series reservoirs is one of the methods to calculate and predict the flow Hydrograph in the catchment. Inverse gamma model is one of probability distributions, which depends on two parameters: n and k. And several formulas have existed for the estimation of the Inverse gamma’s instantaneous unit hydrograph. The accuracy of estimating the parameters n and k in Inverse gamma model directly affect simulation results. This study for the evaluating parameters of the Inverse gamma model used different methods such as moment, optimization and Rosso. The results showed that using optimization method in estimating parameters n, k had the most compatibility with the observed hydrographs. In all these methods, output runoff volume has been calculated with the error less than 11%. The optimization, Rosso and moment methods were successful in computing the time peak and the peak discharge. But in 5 rainfall event, the moment method, in computing the peak discharge has more than 50% of the difference with the observed value. Thus regionalization of Inverse gamma’s model parameters (n and k), by the mentioned methods, is advised for development and application of this hydrological model, in similar catchments.Several formulas have been proposed for the calculation of the Instantaneous Unit Hydrograph (IUH). The concept of series reservoirs is one of the methods to calculate and predict the flow Hydrograph in the catchment. Inverse gamma model is one of probability distributions, which depends on two parameters: n and k. And several formulas have existed for the estimation of the Inverse gamma’s instantaneous unit hydrograph. The accuracy of estimating the parameters n and k in Inverse gamma model directly affect simulation results. This study for the evaluating parameters of the Inverse gamma model used different methods such as moment, optimization and Rosso. The results showed that using optimization method in estimating parameters n, k had the most compatibility with the observed hydrographs. In all these methods, output runoff volume has been calculated with the error less than 11%. The optimization, Rosso and moment methods were successful in computing the time peak and the peak discharge. But in 5 rainfall event, the moment method, in computing the peak discharge has more than 50% of the difference with the observed value. Thus regionalization of Inverse gamma’s model parameters (n and k), by the mentioned methods, is advised for development and application of this hydrological model, in similar catchmentsSeveral formulas have been proposed for the calculation of the Instantaneous Unit Hydrograph (IUH). The concept of series reservoirs is one of the methods to calculate and predict the flow Hydrograph in the catchment. Inverse gamma model is one of probability distributions, which depends on two parameters: n and k. And several formulas have existed for the estimation of the Inverse gamma’s instantaneous unit hydrograph. The accuracy of estimating the parameters n and k in Inverse gamma model directly affect simulation results. This study for the evaluating parameters of the Inverse gamma model used different methods such as moment, optimization and Rosso. The results showed that using optimization method in estimating parameters n, k had the most compatibility with the observed hydrographs. In all these methods, output runoff volume has been calculated with the error less than 11%. The optimization, Rosso and moment methods were successful in computing the time peak and the peak discharge. But in 5 rainfall event, the moment method, in computing the peak discharge has more than 50% of the difference with the observed value. Thus regionalization of Inverse gamma’s model parameters (n and k), by the mentioned methods, is advised for development and application of this hydrological model, in similar catchments..Several formulas have been proposed for the calculation of the Instantaneous Unit Hydrograph (IUH). The concept of series reservoirs is one of the methods to calculate and predict the flow Hydrograph in the catchment. Inverse gamma model is one of probability distributions, which depends on two parameters: n and k. And several formulas have existed for the estimation of the Inverse gamma’s instantaneous unit hydrograph. The accuracy of estimating the parameters n and k in Inverse gamma model directly affect simulation results. This study for the evaluating parameters of the Inverse gamma model used different methods such as moment, optimization and Rosso. The results showed that using optimization method in estimating parameters n, k had the most compatibility with the observed hydrographs. In all these methods, output runoff volume has been calculated with the error less than 11%. The optimization, Rosso and moment methods were successful in computing the time peak and the peak discharge. But in 5 rainfall event, the moment method, in computing the peak discharge has more than 50% of the difference with the observed value. Thus regionalization of Inverse gamma’s model parameters (n and k), by the mentioned methods, is advised for development and application of this hydrological model, in similar catchments.