Evaluation and Comparison of GIUH Model Hydrograph Simulation Results in Different Seasonal Precipitation

Floods are occurring as an environmental hazard in many parts of the world, especially in countries that have been ineffective in crisis management and resource conservation. This natural hazard has become one of the most damaging natural disasters since the reckless activities of human beings in exploiting the natural environment have increased. One of the ways to deal with this danger is to predict the occurrence of floods. The models that are used to predict the occurrence of floods may not have the same accuracy in predicting precipitation events in different seasons of the year. Due to the importance of this issue, in this study, the results of the the Geomorphological Instantaneous Unit Hydrograph (GIUH) model in predicting floods in winter and spring in Minab catchment (Brentin) were compared. The data include the maximum hourly flow and their corresponding precipitation for three spring and three winter events. First, the required parameters of GIUH model including branching ratio, length ratio and area ratio for the basin were estimated using GIS softwar. Then, the events of winter and spring seasons, the peak discharge values, and the time of the peak discharge were compared. The results of this comparison showed that GIUH model predicts peak discharge and peak flood time occurring in winter (with average values of 20.09 and 45.64%, respectively). It is less distant from the observed data, and has a higher accuracy than spring events (with average values of 57.3 and 119.7, respectively).